Non-Neoplastic Hematopathology and Infections E-Book

Hernani Cualing

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1502

Veröffentlichungsjahr: 2012

Beschreibung

Most books on hematopathology are neoplastic in scope and offer little non-neoplastic content. In Non-Neoplastic Hematopathology and Infections, the authors fully describe the hematologic manifestations in tissue and blood of infectious agents, including many rare and exotic diseases found in both Western and Eastern hemispheres, in order to assist pathologists and medical laboratory professionals all over the world in better diagnosing and treating such infections. Thoroughly illustrated with photographs, tables and text, this book features a wide range of non-neoplastic hematologic disorders, as well as reactive patterns of non-infectious and infectious agents. Comprehensive and state-of-the-art diagnostic materials are described, as are the epidemiology, pathobiology, clinical and pathologic manifestations in blood and lymphatic organs--as well as the approaches to treatment. In addition, Non-Neoplastic Hematopathology and Infections: * Contains detailed information on the pathology and patterns of blood, lymph node, and a number of bone marrow and splenic infections and infectious agent manifestations * Thoroughly updates the classic pathology of reactive lymphadenopathies and extends this pattern-based approach to tropical and emergent infections * Promotes the multidisciplinary integration of hematopathologists and microbiologists in the analysis and diagnostic work-up of tissue and blood * Complements current major treatises on such tropical diseases as Manson's, Ashworth's, and Doerr's and updates the classic tomes of William St. Clair Symmers and current texts on neoplastic hematopathology Non-Neoplastic Hematopathology and Infections is an important book for any medical professional interested in non-neoplastic hematology, infections and tissue hematopathology, infectious diseases and tropical medicine, and tropical hematopathology.

Leseprobe

Table of Contents

Title Page

Copyright

Dedication Page

Contributors

Foreword

Preface

Acknowledgments

Introduction

Role of the Hematopathologist

Organization of the Text

Aims and Scope

Part I: Non-Neoplastic Hematology

Chapter 1: Non-Neoplastic Disorders of White Blood Cells

Overview of WBC Production and Function

Quantitative Disorders of WBCS

Qualitative Disorders of WBCS

References

Chapter 2: Non-Neoplastic Disorders of Platelets

Platelet Production Structure and Function

Quantitative Disorders of Platelets

Qualitative Disorders of Platelets

References

Chapter 3: Approach to Disorders of Red Blood Cells

Introduction

The Anemias

The Approach to Anemia

The Polycythemias

References

Chapter 4: Microcytic, Normocytic, and Macrocytic Anemias

Microcytic Anemias

Normocytic Anemias

Macrocytic Anemias

References

Chapter 5: Disorders of Hemoglobin

Overview

Quantitative Disorders of Hemoglobin

Qualitative Disorders of Hemoglobin

Mixed–Quantitative Qualitative Disorders of Hemoglobin

Double Heterozygous States

Approach to Diagnosis of Hemoglobin Disorders

References

Part II: Infectious Aspects of Hematology

Chapter 6: Apicomplexal Parasites of Peripheral Blood, Bone Marrow, and Spleen: The Genera Plasmodium, Babesia, and Toxoplasma

Plasmodium

Babesia

Toxoplasma

References

Chapter 7: Blood and Tissue Flagellates of the Class Kinetoplastidea: The Genera Leishmania and Trypanosoma

Leishmaniasis

Chagas' Disease

African Trypanosomiasis

References

Chapter 8: Proteobacteria and Rickettsial Agents: Human Granulocytic Anaplasmosis and Human Monocytic Ehrlichiosis

Microbiology and Epidemiology of HGA and HME

Clinical Syndromes

Differential Diagnosis

Diagnostic Approach

Prevention and Treatment

References

Chapter 9: Clinically Significant Fungal Yeasts

Introduction

Histoplasma capsulatum var. capsulatum (H. capsulatum)

Blastomyces dermatitidis

Coccidioides immitis

Cryptococcus neoformans

Candida albicans and other Candida Species

Malassezia furfur

References

Chapter 10: Hematologic Aspects of Tropical Infections

Anemia in Tropical Infections

Vascular Purpuras

References

Part III: Non-Neoplastic Lymph Node Pathology and Infections

Chapter 11: Classification of Reactive Lymphadenopathy

Introduction

References

Chapter 12: Lymph Node Biology, Markers and Disease

Peripheral Lymphoid Tissue

Pathophysiology

Cortex

Paracortex

Sinus Histiocytes

Epithelioid Histiocytes and Granulomas

Nodal Framework

References

Chapter 13: Lymphadenopathy with Predominant Follicular Patterns

Germinal Center Hyperplasia

Regressive Transformation of Germinal Center (Atrophic) Pattern

Progressive Transformation of Germinal Center Pattern

Marginal Zone Hyperplasia and Mantle Cell Hyperplasia

Reactive Follicular Pattern, Mixed with Other Patterns, Specific Entities

Mixed Pattern with Follicular Hyperplasia, Microgranulomas, Monocytoid Hyperplasia

Follicular Hyperplasia with Capsular Fibrosis and Plasmacytosis-Syphilis

References

Chapter 14: Reactive Lymphadenopathy with Paracortical Pattern, Noninfectious Etiology

Paracortical Hyperplasia

Dermatopathic Lymphadenopathy

Reactive Immunoblastic Proliferation

Postvaccinal Lymphadenitis

Drug-Induced Lymphadenopathy

Anticonvulsant (Phenytoin)-Related Lymphoproliferative Disorder

Methotrexate-Related Lymphoproliferative Disorder

References

Chapter 15: Reactive Lymphadenopathy with Diffuse Paracortical Pattern—Infectious Etiology

Introduction

Infectious Mononucleosis Lymphadenitis

Cytomegalovirus Lymphadenitis

Herpes Simplex Virus Lymphadenitis

Varicella Zoster Lymphadenitis

References

Chapter 16: Reactive Lymphadenopathy with Sinus Pattern

Sinuses and Vascular Supply

Sinus Histiocytosis, Nonspecific

Signet Ring Histiocytosis

Sinus Histiocytosis with Massive Lymphadenopathy (or Rosai–Dorfman Disease)

Pigmented Sinus Histiocytic Pattern Secondary to Iron Overload from Hemochromatosis, Transfusion, or Hemolysis

Histiocytic Reaction to Foreign Matter

Sinus Pattern from Extramedullary Hematopoiesis

Immature “Sinus Histiocytosis” or Monocytoid B-Cell Hyperplasia

Reactive Hemophagocytic Syndromes

Vascular Transformation of Sinuses (VTS)

Whipple's Disease (WD) Lymphadenopathy

References

Chapter 17: Mixed Lymph Node Patterns: Stromal and Histiocytic Reactions, NonInfectious

Proteinaceous Lymphadenopathy Including Immunoglobulin Deposition Lymphadenopathy

Lymph Node Fibrosis or Fibrotic Changes, Nonspecific

Inflammatory Pseudotumor of Lymph Nodes

Fatty Replacement or Fatty Changes, Nonspecific

Tumor Reactive Granulomatas

References

Chapter 18: Mixed Lymph Node Patterns: Including Granulomatous Lymphadenopathy, Noninfectious

Mixed Pattern with Follicular Hyperplasia and Eosinophilia

Mixed Nonnecrotizing “Dry” Granulomas

Mixed Pattern with Hemorrhage and Infarction

Mixed Necrotizing Pattern with No or Minimal Granulomas

Necrotizing Nonsuppurative Granulomatas

Necrotizing Suppurative Granulomatas

Granulomatous Change within Germinal Centers

Mixed Pattern with Plasmacytosis

References

Chapter 19: Mixed Patterns in Lymph Node, Suppurative Necrotizing Granulomatous Infectious Lymphadenopathy

Cat-Scratch Disease

Tularemia

Lymphogranuloma Venereum

Chancroid, H. Ducreyi

Yersinia Enterocolitica/Pseudotuberculosis Lymphadenitis

Brucellosis

Melioidosis

Typhoid Lymphadenitis (Salmonella Typhi)

References

Chapter 20: Mixed Patterns: Emergent/Tropical Infections with Characterized Lymphadenopathy

Mixed Pattern with Granulomatas and Diagnostic Microorganisms

Lymphadenopathy Secondary to Localized Filariasis

Schistosomiasis

Leishmaniasis

Mixed Pattern with Granulomas and Foamy Macrophages

Mixed Pattern with Deposition of Interstitial Substance

Mixed Pattern with Caseation Necrosis

Mixed Pattern Atypical Mycobacterial Infections in Aids

Mixed Pattern with Angiomatoid Change

Mixed Pattern with Spent Granulomas and Extracellular Organisms

African Histoplamosis Secondary to H. Capsulatum Var Duboisii

References

Chapter 21: Cytopathology of Non-neoplastic and Infectious Lymphadenopathy

Technical Components

Approach to Cytomorphologic Evaluation of Lymph Nodes

FNA Reporting Terminology

Intraoperative Touch Preparation

Reactive Lymphoid Hyperplasia

Inflammatory and Infectious Causes of Lymphadenopathy

Other Causes of Lymphadenopathy

Lymphadenopathy in the Pediatric Patient

Use of Ancillary Studies

Molecular Studies

References

Chapter 22: Mixed Patterns In Lymph Node: Tropical Infectious Lymphadenopathy and Hematopathology, Not Otherwise Characterized

Introduction

Hemorrhagic Lymphadenopathy

Sinus Pattern

Diffuse Pattern with Depletion and Atypical Immunoblastic Reaction

Unusual Granulomas Q Fever

References

Part IV: Non-Neoplastic Findings in Bone Marrow Transplantation

Chapter 23: Non-neoplastic Hematopathology of Bone Marrow Transplant and Infections

Introduction

Fundamental Principles of Hematopoietic Cell Transplantation (HCT)

Characteristics of Pretransplant Bone Marrow

Hematopoietic Regeneration

Chimerism

Post-Transplantation Marrow

Complications of Hematopoietic Regeneration

Conclusion

References

Index

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Library of Congress Cataloging-in-Publication Data:

ISBN: 9780470646007

I dedicate this book to my beloved family: Rawia, Kareem, Phillip, and Andrew; to my teachers

and students; and to my native and adopted country, the Philippines and USA.

Hernani D. Cualing, MD

To my hematology gurus Dr A Bagg, Dr M Kadin, Dr T Singh and my students for the inspiration

and to my husband Pankaj, my daughters Kaveri & Kimya for their unyielding

support through the perspiration.

Parul Bhargava, MD

To Mayra, my wife, and Beatriz, my daughter, who constitute the pillars

of inspiration and strength in my life!

Ramon L. Sandin, MD

Contributors

Stephen D. Allen, MD

James Warren Smith Professor of Clinical Microbiology

Professor, Department of Pathology and Laboratory Medicine

Indiana University School of Medicine

Indiana University Health

Indianapolis, IN

Ernesto Ayala, MD

Assistant Professor

Bone Marrow Transplant Division, Department of Oncologic Science

Moffitt Cancer Center and Research Institute

Tampa, FL

Parul Bhargava, MD

Medical Director, Hematology Laboratory at Beth Israel Deaconess Medical Center

Assistant Professor

Beth Israel Deaconess Medical Center—Needham Campus

Member of Harvard Medical Faculty Physicians (HMFP)

Boston, MA

Jeremy W. Bowers, MD

Hematopathology Fellow

Department of Hematopathology and Laboratory Medicine

Moffitt Cancer Center and Research Institute

Department of Pathology and Cell Biology

University of South Florida, College of Medicine

Tampa, FL

Sheldon Campbell, MD, PhD, FCAP

Department of Laboratory Medicine

Yale University School of Medicine

Pathology and Laboratory Medicine

VA Connecticut, West Haven, CT

Hernani D. Cualing, MD

Joint Associate Professor, Department of Pathology and Cell Biology

University of South Florida, College of Medicine

Medical Director, IHCFLOW, Inc.

Consultant Hematopathologist, Specialty: Hematopathology, Cutaneous Lymphomas, and Imaging Science

Post-Director of Hematopathology Fellowship-Moffitt Cancer Center and Research Institute

Shohreh Iravani Dickinson, MD

Assistant Professor, Moffitt Cancer Center and Research Institute, Department of Pathology and Cell Biology, University of South Florida, COM

Anatomic Pathologist and Hematopathologist

Jason C. Ford, MD, FRCP(C)

Head, Division of Hematopathology, Children's and Women's Health Centre of BC

Associate Professor, Faculty of Medicine

University of British Columbia

BC, Canada

Lynne Garcia, MS, MT, FAAM

Clinical Microbiologist

Director, LSG & Associates, Santa Monica, CA

Gary Hellermann, PhD

Assistant Professor

Division of Allergy and Immunology

Department of Internal Medicine

University of South Florida College of Medicine

Tampa, FL

Vandita Johari, MD

Department of Pathology

Division of Clinical Pathology

Director, Hematology Laboratory and Flow Cytometry

Assistant Professor of Pathology

Tufts University School of Medicine

Lija Joseph, MD

Staff Hematopathologist

Lowell General Hospital

Adjunct Associate Professor

Boston University School of Medicine

Boston, MA

Loveleen C. Kang, MD

Associate Professor

Department of Pathology

University of South Florida

College of Medicine

Staff Pathologist

James A. Haley VAMC

Tampa, FL

Walid E. Khalbuss, MD, PhD, FIAC

Associate Professor

Director of Cytopathology-UPMC Shadyside Hospital

Department of Pathology

University of Pittsburgh Medical Center (UPMC)

UPMC-Shadyside, Pittsburgh, PA, USA

Rebecca Levy, MD

Department of Pathology

Baystate Medical Center

Springfield, MA, USA

Jun Mo, MD

Associate Professor

Pediatric Hematopathology

Division of Pathology

Cincinnati Children's Hospital Medical Center

Cincinnati, OH, USA

Sara E. Monaco, MD

Assistant Professor

Director of Fine Needle Aspiration Biopsy Service-UPMC Children's Hospital of Pittsburgh

Department of Pathology

University of Pittsburgh Medical Center (UPMC)

UPMC-Shadyside, Pittsburgh, PA, USA

Taiga Nishihori, MD

Assistant Member

Department of Blood and Marrow Transplantation

Moffitt Cancer Center, Tampa, FL

Tal Oren, MD, PhD

Department of Pathology

Stamford Hospital

Suffern, NY, USA

Liron Pantanowitz, MD

Associate Professor

Director of Fine Needle Aspiration Clinic-UPMC Shadyside Hospital

Department of Pathology

University of Pittsburgh Medical Center (UPMC)

UPMC-Shadyside, Pittsburgh, PA, USA

Deniz Peker, MD

Clinical Fellow, Hematopathology Fellowship Program

Moffitt Cancer Center and Research Institute

Department of Pathology and Cell Biology

University of South Florida College of Medicine

Ramon L. Sandin, MD, MS, FCAP, ABP–MM

Clinical Pathologist

Medical Director, Clinical Microbiology and Virology

Senior Member and Professor Department of Hematopathology and Laboratory Medicine, and Blood and Marrow Transplant Program

Moffitt Cancer Center

Betram Schnitzer, MD

Professor Department of Pathology

University of Michigan Ann Arbor

Ann Arbor, MI

James W. Smith, MD

Nordschow Professor Emeritus of Tropical Medicine

Van Nuys Medical Science

Former Chair Dept. of Pathology & Laboratory Medicine

Indiana Univ. School of Medicine

Indianapolis, Indiana

Raul E. Villanueva, MD

Clinical Pathologist

Puget Sound Institute of Pathology

Seattle, WA

Dr. Reza Setoodeh, MD

Department of Pathology and Cell Biology

University of South Florida College of Medicine

Ling Zhang, MD

Assistant Professor

Hematopathologist

Department of Hematopathology and Laboratory Medicine

Moffitt Cancer Center and Research Institute

Department of Pathology and Cell Biology, USF

Xiaohui Zhang, MD, PhD

Resident-Fellow, Hematopathology Fellowship

Moffitt Cancer Center and Department of Pathology and Cell Biology

University of South Florida College of Medicine

Foreword

Many years ago, when I began my residency in pathology, there seemed to be few, if any, textbooks dealing exclusively with the topic of hematopathology. The general pathology texts then available usually contained only short, cursory chapters on lymph node and bone marrow findings in such diseases as lymphomas and leukemias. However, only multiple rudimentary classifications of these two neoplastic disease entities were described. Ever since the AFIP fascicle on Classification of Lymphomas by Dr. Henry Rappaport appeared in 1966, however, numerous books on the subject of hematopathology have been published.

With the exception of the now out-of-date multiple-volume set by William St. Clair Symmers, there are, to my knowledge, no other textbooks combining the fields of hematopathology and Western or tropical infectious diseases. Now, in this book, Dr. Cualing and his fellow contributors have successfully combined these two areas of expertise.

The current volume is especially timely in this era of globalization when people from all over the world travel into our midst, bringing with them diseases that we are unfamiliar with. In other instances, pathologists from other countries send slides for consultation from patients who have a variety of disorders. Thus, more than ever, there is a pressing need for the development of a closer interaction between hematopathology and microbiology in the investigation of infectious and benign reactive diseases particularly those involving lymph nodes, blood, and bone marrow. This book has as its mission the integration of these two disciplines leading to further collaboration and understanding between hematopathologists and microbiologists.

Bertram Schnitzer, MD

Preface

This book explores new material at the nexus of hemic-lymphatic manifestations of Western and tropical infectious diseases. It attempts to expand on the classic descriptions of the reactive and inflammatory manifestations of infectious diseases in blood and other related organs. Because many agents seek entry and circulate in blood and lymphatic system, the book begins with the basics of hematology and follows with blood-borne infections. It adds in a survey of patterns of reactions in blood and lymph nodes and ends with hematopathology of bone marrow transplantation. Many of the agents of infections diseases, in addition to human to human transmission, are zoonotic, use a number of vectors, and hence epidemiologic and geographic aspects are included. Upon entry, a number of these agents commandeer blood elements including lymphocytes and macrophages as mobile shuttles. Both blood and lymphatic disorders are therefore elaborated since direct effect by these agents cause red cell, platelets, leucocytes, and tissue immunologic disorders. All these disorders are illustrated with pictures, tables, descriptive and text; illustrated as well are the range of non-neoplastic hematologic disorders, and reactive patterns of noninfectious and infectious agents, and the blood and lymphatic manifestations of familiar infections and the more common infections in the tropics. The epidemiology, pathobiology, and clinical and pathologic manifestations in blood and lymphatic organs as well as the approach to diagnosis, treatment, and prognosis are described. For uniformity of terminology, the book includes WHO-endorsed diagnostic codes based on the International Classification of Disease (ICD-10). Since many infectious agents are also of tropical origin, and since the vast majority of these agents infect a large segment of the world, including transient travelers and immigrants, this book incorporates diseases found in both Western and Eastern Hemispheres. Additionally the microscopic criteria as well as the molecular and laboratory tests provided in this code should prove useful information even for laboratories practicing in resource limited settings besides those with access to modern diagnostic modalities.

We divided the book into four parts. Part I provides an overview of non-neoplastic hematology, Part II addresses blood-borne infections, Part III covers patterns seen in noninfectious and infectious lymphadenopathies, including those commonly seen in tropical countries as well as cytomorphologic findings of reactive adenopathies, and Part IV deals with hematopathologic issues of bone marrow transplantation associated with common and rare infections. We begin the book with a section on the basics of hematology and diagnosis based on peripheral blood findings, then go on to infections related to hematopathology, followed by tissue and pattern-based diagnosis, and finally cover the basics of bone marrow transplantation. In tissue, we proffer an approach using low-power recognition of the histology patterns and proceed from there. The basics of hematology written by practicing experts in the field is completely and succintly covered in Part I, detailing issues on leucocytes, platelets, and red cells disorders including thalassemias. Part II covers blood-borne infections written by well-known practicing microbiologists and includes apicomplexas, flagellates, protobacterias, and fungal infections. In Part III, practicing hematopathologists discuss the issue of reactive lymphadenopathy and present a table detailing the entities under the classic four patterns: follicular, diffuse, sinus, and mixed patterns. The premise for this approach is that knowledge of the salient morphologic findings, the constellation of clinical presentation, the geographic or epidemiological background of the patient, and the key laboratory and the morphologic manifestations will help in arriving at a correct diagnosis. In other words, we begin at the beginning: approach a disease from what we all see under the microscope.

The difficulty in diagnosing reactive lymphadenopathy rivals, if not exceeds, that of the lymphomas. The case of recognizing a reactive lymph node belies its complexity, and contributes to the generally nonchalant attention it receives compared to its malignant cousin. Just as in the case of lymphomas, there is an approach that makes sense of these numerous complexities as well as a framework to formulate diagnoses. Historically the many ways to classify lymphadenopathies has been hindered by the artifice of easy understanding and simple diagnosis. Partly to blame is the notion that “it is just benign, who cares what kind” until the lymphoma is mistaken for a benign diagnosis, or a treatable infection, or one that is highly contagious is missed. Often the lack of clinical history compounds the limited microscopic window that a pathologist initially sees. Hence we use the approach of hematopathologists: we widen the microscopic window to observe what are the pitfalls, the clinical milieu, and the subtle histologic features that differentiate rival entities.

Non-neoplastic hematopathology is a difficult diagnosis not only because of the reactive lymph node's mimicry of lymphomas but also because the field has received less studious attention than its neoplastic counterpart. Inherently, reactive lymph nodes are also difficult to diagnose because lymph nodes, upon stimulation, display a dynamic variability that depends on the patient's age, immune status, phase or duration of reaction, and whether the etiology is infectious or noninfectious. About 30 to 40% of reactive lymph nodes have specific histologic features leading to a definite diagnosis: features in histology suggest a pattern that requires ancillary serology, phenotypic, or serologic tests that may lead to a specific diagnosis. The rest of lymph nodes seen in pathology practice may show a nonspecific histology, but its pattern needs to be stated to initiate a pattern-based differential diagnosis. Even for a nonspecific reactive hyperplasia, such as a mixed follicular and paracortical reaction, diagnosis is important because of the implicit concern for a lymphoma is considered and not favored. A specific reactive lymphadenopathy diagnosis, when suggested by a constellation of clues, needs to be given so that confirmatory tests can be performed. A diagnosis of infection would impel a therapy to commence, surveillance made for endemic and communicable disease, and malignancy ruled out.

We also take a lesson from a Family Circus cartoon by Bil Keane: kids looking over an adult reading a book say “Grown-up books are harder to read … they make you think up your own pictures!!!” by incorporating many color pictures. We try to fill in with more guideposts a map of non-neoplastic hematopathology that is already dotted with classic landmarks. We are indebted to hematopathology pioneers who described reactive lymphadenopathy and its classic patterns. Bertram Schnitzer (1992) and Lawrence Weiss (2008). As we extend their work into the realm of the infectious diseases, we are indeed navigating a wondrous terra incognita as the fictional sailors of Lewis Carroll: We hope the readers will be as excited to fill in the blanks.

He had brought a large map representing the sea,

Without the least vestige of land:

And the crew were much pleased when they found it to be

A map they could all understand.

“Other maps are such shapes, with their islands and capes!

But we've got our brave Captain to thank”

(So the crew would protest) “that he's brought us the best—

A perfect and absolute blank!”

L. Carroll, Fit the Second, the Hunting of the Snark

Hernani D. Cualing

Parul Bhargava

Ramon L. Sandin

Acknowledgments

We, at the onset, would like to express our gratitude to the staff of Wiley-Blackwell Publishers, and especially to our ever gracious medical editor, Thom Moore. We also thank Ian Collins, Editorial Assistant, Dean Gonzalez, Illustration Manager, and Danielle Lacourciere, Senior Production Editor, Maude Akagi and James Hastings of Wiley, as well as Gowri Vasanthkumar of Laserwords, India for their labor and patience in converting our texts to a book as flawless as possible. Since we may not be able to thank all the staff who made this book possible, we ask leave for not including everyone. I would also like to thank my former mentors who started me on the path to hematopathology: Dr. Jen Lin of New York and Drs. Dick Neiman and Atillio Orazi, formerly of Indianapolis, where I had my hematopathology fellowship. Since that time, I collected microscopic slides intending to use them and during my stint as faculty of University of Cincinnati, under Dr. Roger Smith and Dr. Fenoglio-Preiser, for teaching: my first cases of lymph node dirofilariasis and leishmaniasis of bone marrow came from that fellowship and were augmented with pearls to many slide boxes of reactive lymphadenopathies over the years. For the book, additionally would like to thank the following persons and are indebted for their contributions of images, comments, and suggestions.

We are indebted to Dr. Betram Schnitzer for his support and for his endorsement of the book. Much of our tropical infectious digital images were provided by Dr. Wun-Ju Shieh, of the Infectious Diseases Pathology Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention at Atlanta, and we could not thank him and his colleagues enough. Dr. Elmer Koneman, a foremost microbiologist, provided us with rare images of infections in tissues, and we also appreciate his comments on materials to include at the front of the book. We thank Dr. Rito Zerpa Larrauri of Servicio de Microbiología, Instituto Nacional de Salud del Niño, Lima, Peru for blood and tissue images of leprosy, bartonellosis, and mycobacteria. We would also like to thank Karen Goraleski, Executive Director of the American Society of Tropical Medicine and Hygiene for allowing us to use digital images of tropical diseases from Dr. Herman Zaiman collections. We are encouraged by the vision and thrust of the ASTMH and support their mission to educate and publish on tropical medicine of widespread emergent or neglected tropical infections. We thank Dr. Fabio Fachetti of the Department of Pathology Spedali Civili-University of Brescia, Italy, for the image of CD123 and for personal communication on plasmacytoid monocytes and lymphadenopathies. We additionally are indebted to Dr. James Smith of Indiana University Medical Center, to Dr. Rodney C. Arcenas of Holywood, Florida, for reviewing most of the manuscript, to Dr. Ronald Jaffe of Pittsburgh Children's Hospital, to Kathy White of Boston Medical Center, and to Dr. J. Ford of Children's Hospital, Vancouver, Canada. We thank Rodney C. Arcenas PhD, Ardeshir Hakam MD of Mofffitt Cancer Center, Antonio Hernandez MD of Quest Dx/Ameripath Center for Advanced Diagnostics, and Dr. Steve Shaw of NIH/NCI for providing scholarly materials discussing the paracortical cords. We also thank Dr. Steve Swerdlow, chief hematopathologist at the University of Pittsburg, for sharing digital images of CML lymphadenitis. We thank Dr. Gary Hellerman for facilitation of email communications at the beginning of the project and for editing parts of the manuscript and also Gary Bentley for helping with line art figures as well as to Dr. Peter Banks for his images on Herpes simplex Lymphadenitis. We are indebted to Ms. Malou Domingo of Manila, the Philippines, for research in tropical pathology and to Dr. Sharon Villanueva of Kyushu University Fukuoka, Japan, for articles on leptospirosis and to Philip Yassin-Cualing, for research and editing work.

Hernani D. Cualing

Lutz, Florida

Introduction

Role of the Hematopathologist

The hematopathologist has a vital role in the laboratory. The hematopathologist functions as both a consultant and diagnostician in anatomic and laboratory medicine evaluations of a clinical pathology nature. In the evaluation of specimen that come to the clinical laboratory medicine, including tissue, blood, and fluids, the hematopathologists act as both a teacher and consultant to residents, clinician practitioners, medical students, and other community practitioners. Often it is the hematopathologist who is charged with arriving at a hematopathology related diagnosis.

In anatomic pathology a thorough hematopathology assessment includes evaluations of lymph node, skin, spleen, thymus, and extranodal flare-ups suggesting lymphoma or leukemia. A classic description of both noninfectious and infectious pattern of lymphadenopathy is included as groundwork for formulating a diagnosis. “Wet” hematology consists of evaluations of peripheral blood smears, body fluids, and the bone marrow, and knowledge of non-neoplastic disorders is a crucial step in further evaluating infectious disorders that target the blood and blood vessels. Hematologic manifestations of infectious agents as well as blood-borne diseases are a critical consideration in the formulation of a diagnosis. This book addresses the need to have the work of the hematopathologist closely integrated with that of the microbiologists and infectious disease practitioners, in evaluating infections from tissue and blood specimens.

When tissue is procured for diagnosis, the clinician, the anatomic pathologist, the cytopathologist, the microbiologist, and the hematopathologist should act as a team to ensure correct handling and processing of the specimen. Along with the need for ancillary tests like flow cytometry, clonality, or molecular cytogenetic studies, specimen portions for culture or direct smears should be processed when they are still fresh and uncontaminated in order to optimize handling and lead to a correct diagnosis. More and more evident is that hematopathologic diseases are related to immune and infectious etiology. In pediatric hospitals, disease patterns suggest congenital and immune reactions. In centers where chemotherapy and organ transplantations are performed, patients are at high risk of contracting infections and hematologic manifestations of infections.

The global economy and the global information superhighway have made people of distant lands neighbors. Hence more and more of the specimens that the hematopathologists see come from across the seas. The differential diagnosis widens to include exotic infectious diseases beyond the typical diseases found in the Western Hemisphere.

This book addresses the confluence of hematopathology and infectious diseases. To the clinicians as well as to medical personnel seeing patients from abroad, the role of hematopathologists extend beyond regional or locally based diagnosis. Today's perplexing disorders include lymphadenopathy, splenomegaly, hemorrhagic fever, unexplained cytopenias, petechiae, and skin rashes associated with common and rare infections. Knowledge of the salient morphologic findings, the constellation of clinical presentation, the geographic or epidemiological background of the patient, and the key laboratory and the morphologic manifestations can help in arriving at a correct diagnosis.

Organization of the Text

The text is divided into four parts. Part I provides an overview of non-neoplastic hematology, Part II addresses blood-borne infections, Part III covers patterns seen in noninfectious and infectious lymphadenopathies, including those commonly seen in tropical countries as well as cytomorphologic findings of reactive adenopathies, and Part IV deals with hematopathologic issues of bone marrow transplantation. In almost all chapters, we included ICD-10 codes (International Classification of Diseases) to advance use of common terminologies.

Aims and Scope

Our objective is to present new material on hemic-lymphatic diseases, with a view toward their infectious manifestations. The studies in this book expand on the classic descriptions of reactive and inflammatory expressions of infectious diseases in blood and lymph nodes. The many infectious diseases that enter and circulate in blood and the lymphatic system produce patterns of reactions. We attempt to elucidate these patterns, and additionally epidemiologic and geographic factors where the agents of disease are zoonotic and can use a number of vectors. Upon entry some more pernicious agents commandeer lymphocytes and macrophages as mobile shuttles and cause blood and lymphatic disorders. Their direct effects on red cells, platelets, leucocytes, immunologic disorders are elaborated with pictures and tables, and likewise are treated herein the reactive patterns of agents of common infectious and noninfectious diseases. The various diseases' epidemiology, pathobiology, and clinical and pathologic expressions in blood and lymphatic organs are described as well as approaches to diagnoses, treatments, and prognoses. Because many infectious agents are from tropical regions that infect many peoples worldwide, via transient travelers and immigrants, we also cover diseases found at these latitudes of the Eastern and Western Hemispheres.

Part I

NON-NEOPLASTIC HEMATOLOGY

Chapter 1

Non-Neoplastic Disorders of White Blood Cells

Rebecca A. Levy, Vandita P. Johari, and Liron Pantanowitz

Overview of WBC Production and Function

Frequently the first test that suggests an imbalance or disturbance in hematopoiesis is the complete blood count (CBC). The CBC is a simple blood test that is ordered frequently. It may pick up incidental abnormalities or may yield a diagnosis of suspected abnormalities. The CBC is a count of multiple blood components and qualities, and can include a differential of the white blood cells (WBCs). The CBC can suggest infection, inflammatory processes, and malignant processes. Typically a peripheral blood smear and rarely a buffy coat (concentrated white blood cells) are analyzed to help determine a diagnosis (Efrati, 1960). A differential WBC assigns leukocytes to their specific categories as a percentage or absolute count. Manual differential counts tend to be accurate but imprecise, whereas automated counts are fairly precise but sometimes inaccurate (Bain, 2002). It may occasionally be necessary to evaluate both the bone marrow and blood smear to evaluate the quality and quantity of the blood lineages. WBC disorders are classified into quantitative and qualitative conditions, reflecting changes in their number and function, respectively (Stiene-Martin, 1998). This chapter discusses both nonneoplastic quantitative and qualitative disorders of WBCs.

Leukocytes

Hematopoeisis

Hematopoiesis occurs in different parts of the body, depending on the age of the embryo, child, or adult. Initially blood cell formation of the embryo occurs within the yolk sac, in blood cell aggregates called blood islands. As development progresses, the hematopoiesis location changes, and the spleen and liver become the primary sites. As bone marrow develops, it usurps the task of blood cell formation and becomes the site for trilineage hematopoiesis. The bone marrow contains pluripotent stem cells, which can develop into any of the blood cells, including granulocytes, monocytes, and lymphocytes, in response to specific stimulating factors (Andrews, 1994). Several white blood cells (leukocytes) are depicted in Figure 1.1. Maturation, activation, and some proliferation of lymphoid cells occur in secondary lymphoid organs, including the spleen, liver, and lymph nodes. Extramedullary hematopoiesis can take place in the liver, thymus, and spleen and may lead to organomegaly. There is a common myeloid progenitor cell called the CFU-GEMM (Colony-Forming Unit-Granulocyte–Erythroid-Macrophage-Megakaryocyte) that leads to the development of granulocytic, monocytic, eosinophilic, basophilic, erythrocytic, and megakaryocytic precursors.

Figure 1.1Schematic drawings of different white blood cells shown in relation to an erythrocyte. The band neutrophil (10–18 μm) is characterized by a deeply indented nucleus and secondary granules. The segmented neutrophil (10–15 μm) has 2 to 5 nuclear lobes (4 depicted) connected by thin filaments and contains several cytoplasmic secondary (specific) granules. The basophil (10–15 μm) contains a segmented nucleus and many coarse, dense granules of varying size (that may obscure the nucleus). The eosinophil (10–15 μm) has a bilobed nucleus and cytoplasm filled with coarse, uniform granules. The monocyte (12–20 μm) has an indented nucleus and abundant gray cytoplasm with sparse granules. The presence of nucleoli indicates that this is an immature monocyte (promonocyte). The mature lymphocyte (7–15 μm) has a high nuclear:cytoplasmic ratio (4:1), slightly notched nucleus with dense clumpy chromatin and no nucleolus, and only moderate agranular cytoplasm.

Leukocytosis

Leukocytosis is defined as a total WBC count that is greater than two standard deviations above the mean, or a value > 11, 000/μL in adults. While leukocytosis is mainly due to a neutrophilia, it may reflect an increase in any of the other leukocytes. Patients with hyperleukocytosis, which is defined as a white cell count (WCC) > 100, 000/μL, may manifest with hyperviscosity (or so-called symptomatic hyperleukocytosis). The development of symptoms of hyperviscosity syndrome are often correlated with the underlying cause (e.g., hyperproteinemia, erythocytosis, hyperleukocytosis, and thrombocytosis) and is a medical emergency mainly seen with leukemia in blast crisis. The severity of hyperleukocytosis is related to the underlying disorder; hyperviscosity is typically evident in AML with a WCC of > 100, 100/μL, in ALL with a WCC of > 250, 000/μL, and in CLL with a WCC of 500, 000/μL (Adams, 2009; Rampling, 2003). Spurious leukocytosis can occur because of platelet clumping, increased nucleated erythrocytes, or in cryoglobulinemia (Savage, 1984; Patel, 1987).

Leukemoid Reaction

Leukemoid reaction is used to describe leukocytosis above 50, 000/μL. This is usually characterized by a significant increase in early neutrophil precursors including band forms (Figure 1.2). Infants with Down syndrome may have transient leukemoid reactions (Brodeur, 1980).

Figure 1.2Leukemoid reaction observed in a peripheral blood smear. Notice the significant increase in early neutrophil precursors and band forms in addition to segmented neutrophils.

Granulocytes

Granulocytes have a single progenitor cell, the myeloblast, that can differentiate into neutrophils, eosinophils, and basophils (Lawrence, 1998). The differentiation process is based on the presence of certain stimulating factors. Neutrophils are the first responders to infection or inflammation, and they respond to cytokines such as interleukin-8 (IL-8), interferon gamma (IFN-gamma), and C5a (Witko-Sarsat, 2000). These chemicals direct the neutrophils migration to areas of need.

Maturation Process

Neutrophils undergo a maturation process as they shift from myeloblasts, to promyelocytes, to myelocytes, to bands; eventually they finish the maturation process as neutrophils which is depicted in Figure 1.3. Only bands and mature neutrophils are normally present in the peripheral blood smear. Other immature cells are very rarely detected in small numbers in the blood of healthy individuals (Oertel, 1998). Band neutrophils constitute about 10 to 15% of the nucleated cells in the bone marrow and around 5 to 10% of the nucleated cells in the peripheral blood (Glassy, 1998). The nucleus of a band is indented to greater than 50% of the diameter of the nucleus (i.e., horseshoe shaped). Eosinophils have the same maturation process; however, the cells are distinctively eosinophilic, with coarse eosinophilic cytoplasmic granules. In this case the myeloblast becomes an eosinophilic myelocyte that matures into an eosinophilic metamyelocyte, then an eosinophilic band, and ultimately an eosinophil. Basophils have a shorter transition from a myeloblast to a basophilic myelocyte and eventually a basophil.

Figure 1.3Neutrophil maturation process. Neutrophils undergo a maturation process as they shift from myeloblasts, to promyelocytes, to myelocytes, to bands, and eventually to neutrophils.

Left Shift

An increase ( > 20%) in the number of band cells (so-called bandemia) in relation to normal neutrophils is known as a left shift (Figure 1.4) (Nguyen, 2000). With a left shift the band count is usually > 700/μL. When a left shift occurs, more immature granulocytes (blasts, promyelocytes, metamyelocytes, myelocytes) are typically released in the peripheral blood. Unless a patient is receiving G-CSF therapy, circulating blasts are not normally seen in reactive conditions. In reactive neutrophilia the left shift contains mainly bands. A left shift may be physiological (e.g., pregnancy) or in response to infection, inflammation, shock, hypoxia, or other marrow stimulation. Newborn infants may normally show leukocytosis and a leftward shift (Christensen, 1979). Although the diagnostic value of a left shift as an indicator for infection is limited (Seebach, 1997; Gombos, 1998), when the WBC is low, bands may be the only clue of an infection. Occasionally band cell counts are requested to detect infection (e.g., in the neonate) (Bain, 2002). The presence of a left shift and circulating nucleated red blood cells is referred to as a leukoerthyroblastic reaction (or leukoerythroblastosis). There is often also associated erythrocyte anisopoikilocytosis (e.g., teardrop cells or dacrocytes) with anemia and megakaryocyte fragments in a leukoerythrobalstic pattern, indicative of a space-occupying lesion within the marrow (i.e., myelophthisic process).

Figure 1.4Blood smear from a patient with infection showing a bandemia and a left shift. These band neutrophils all have nuclei that are indented to greater than half the distance from the farthest nuclear margin. Their cytoplasm also contains many toxic granules.

Monocytes

Monocytes stem from monoblasts and undergo a maturation process as they progress from monoblasts to promonocytes. Monocytes reside in the peripheral blood. They may differentiate further and become macrophages (sometimes referred to as histiocytes) in the tissue.

Lymphocytes

Lymphocytes differentiate from a precursor cell known as a common lymphoid progenitor cell. They can become a precursor T cell/natural killer (NK) cell or a precursor B cell. These cells then become committed to their designation as they develop into Pro-T cells, Pro-NK cells, and Pro-B cells. Further maturation is required as the cells proceed in their development and exhibit morphologically recognizable precursors as Pre-T cells and Pre-B cells. The cells undergo their maturation in distinct locations: B lymphocytes in the bone marrow and T lymphocytes in the thymus. Following this detailed maturation process (Figures 1.5 and 1.6), lymphocytes enter the blood circulation and reside in secondary lymphoid organs, including the spleen and lymph nodes.

Figure 1.5Differentiation of B cells. Precursor B cells may develop into naïve B cells, or may undergo apoptosis. Antigen stimulation of a naïve B cell starts a cascade of events including clonal expansion, somatic hypermutation and class switching of centroblasts. Centroblasts then develop into centrocytes within the follicle center and with the follicle dentritic cell (FDC) or undergo apoptosis. The perifollicular area contains either plasma cells or memory B cells.

Figure 1.6Differentiation of T cells. Progenitor T cells may develop into NK cells in the periphery, or they may enter the thymus where they develop into supcapsular cortical thymocytes and continue on to common thymocytes or apoptotic cells. Common thymocytes are CD4 + and CD8 + , which then develop into medullary thymocytes and naïve T cells, either as CD4 + or CD8 + . The naïve T cells are stimulated by antigens and transform into effector and memory T cells. T helper cells (TFH) develop from CD4 + naïve T cells within the follicle with the follicle dendritic cell (FDC).

Quantitative Disorders of WBCS

Disorders of Neutrophils

Normal Neutrophil Physiology

In normal adults the bone marrow is the usual site of differentiation, proliferation, and terminal maturation of hematopoietic stem cells into neutrophil progenitors. Maturation of myeloblasts into segmented neutrophils usually occurs in five phases: blast, promyelocyte, myelocyte, metamyelocyte, and mature neutrophil. Division occurs only during the first three stages (i.e., neutrophil blast, promyelocyte, and myelocyte). After the myelocyte stage, the cells are no longer capable of mitosis and enter a large marrow storage pool. After 5 days the cells are released into the blood, where they circulate for a few hours before entering tissues (Nathan, 2006). The physiology of neutrophil function is covered in greater detail in the qualitative disorders of neutrophils section. A neutrophil is also referred to as a polymorphonuclear neutrophil (PMN). The qualitative and quantitative changes of neutrophils noted in response to infection include neutrophilia, left shift, toxic granulation, Döhle bodies, and vacuolization (see below).

Normal Neutrophil Morphology

The nucleus of the circulating neutrophil is segmented, usually with two to four interconnected lobes. The purpose of nuclear segmentation is unknown. In rare situations (mainly with hematological malignancy, but also following G-CSF therapy) neutrophils may have unusual nuclear shapes such as ring/donut or botryoid nuclei or show detached nuclear fragments (Hernandez, 1980; Bain, 2002). Some mature neutrophils in women have a drumstick- or club-shaped nuclear appendage attached to the nuclear lobe by a single fine chromatin strand containing the inactivated X chromosome (Barr body). Females typically have six or more drumsticks per 500 PMNs (Davidson, 1954). In males with Klinefelter syndrome (XXY), drumsticks occur but are fewer in number (Bain, 2002).

The myeloblast is an immature cell with a large oval nucleus, sizable nucleoli, and few or no granules. The promyelocyte stage contains primary (azurophilic or nonspecific) large peroxidase-positive granules that stain metachromatically (reddish-purple) with a polychromatic stain such as the Wright stain. During the myelocyte stage of maturation, secondary (specific) granules are formed that are peroxidase negative. After the myelocyte stage, the primary granules lose their intense staining properties and are no longer evident by light microscopy (DeSantis, 1997). Mature segmented neutrophils contain primary (peroxidase-positive) granules and specific (peroxidase-negative) granules in a 1:2 ratio. The granules cannot be distinguished individually but are responsible for the pink background color of the neutrophil cytoplasm seen during and after the myelocyte stage. Primary granules contain lysozyme, myeloperoxidase, acid phosphatase, elastase, defensins, and cathepsin G. Secondary granules contain lysozyme, collagenase, lactoferin, B12-binding protein, NADPH oxidase, and cytochrome b. A third type (tertiary) granule identified by electron microscopy has been documented.

When evaluating the granularity of neutrophils, it is important to be aware of possible artifacts such as may arise from prolonged storage and suboptimal staining. Toxic granulation (increased granulation) refers to activated neutrophils that contain large purple or dark blue primary granules (Figure 1.7 and Figure 1.8). With toxic granulation the cytoplasmic granules enlarge and stain darker than normal granules (Schofield, 1983). Neutrophils with toxic granules may resemble eosinophils (which have larger granules), basophils, monocytes, or the inclusions of Alder–Reilly anomaly (see later). Activated neutrophils may in addition contain multiple round, empty cytoplasmic vacuoles and Döhle bodies. Blood stored for prolonged periods can artifactually cause vacuoles. Cytoplasmic vacuolation can also be caused by autophagocytosis (e.g., following chloroquine or sulfonamide therapy). Döhle bodies are blue-gray inclusions seen in the cytoplasm that represent areas of rough endoplasmic reticulum. They may be single or multiple and of varying size. Döhle-like bodies can also be found in patients with May–Hegglin anomaly, burns, myelodysplasia, and in pregnancy (see later). In May–Hegglin anomaly these bodies correspond to amorphous cytoplasmic areas devoid of organelles. Increased granulation is also a characteristic of G-CSF therapy (Schmitz, 1994). Compared to toxic granulation, however, hypergranulation induced by G-CSF therapy has a higher density of granules, which stain more red and often obscure the nucleus (Nguyen, 2000). Other changes that may be encountered in patients receiving growth factor therapy include a neutrophilia with a prominent left shift, Döhle bodies, nuclear segmentation abnormalities (hyposegmentation, hypersegmentation, ring nuclei), leukoerythroblastosis, and rarely a monocytosis, transient lymphocytosis, and eosinophilia. Alder–Reilly anomaly (see later), when present in granulocytes, can also mimic toxic granulation. Alder–Reilly bodies, however, tend to be larger than normal granules. Finally, nuclear projections and cytoplasmic pseudopodia may be observed as rare alterations in toxic neutrophils.

Figure 1.7Schematic diagram of a toxic segmented neutrophil. The key features are prominent cytoplasmic granules, clear vacuoles, and Döhle bodies located peripherally adjacent to the cell membrane.

Figure 1.8Neutrophils with toxic granulation seen in a patient with known infection.

Table 1.1 lists several of the alterations and abnormalities that may be seen in neutrophils. Apoptotic neutrophils may be seen in association with infection, diabetes (Figure 1.9), glucocorticoid administration, and neoplastic diseases (Sudo, 2007; Shidham 2000), but may also occur if blood is left at room temperature for a long time. These are important to recognize as they may mimic nucleated RBCs on low-power examination. Neutrophils may also contain a variety of phagocytosed material such as bacteria, fungi, cryoglobulin, and malarial pigment. (Figure 1.10).

Figure 1.9Neutrophil apoptosis in the peripheral blood of a patient with diabetes mellitus. Apoptotic cells have round, dense pyknotic nuclei.

Figure 1.10Peripheral blood smear from a patient with Ehrlichiosis (human granulocytic anaplasmosis due to infection with the HGA agent E. phagocytophila). The neutrophils contain characteristic intraleukocytic morulae. These may resemble Döhle bodies. Such intracytoplasmic inclusions may be seen in the cytoplasm of neutrophils in many (20–80%) patients with human granulocytic ehrlichiosis and in mononuclear cells in a minority (1–20%) of patients with human monocytic ehrlichiosis.

Table 1.1 Alterations of Neutrophil Morphology

AbnormalityConditionNeutrophil nucleiLeft shiftPregnancy, infection, shock, hypoxiaHypersegmentationMegaloblastic conditions, iron deficiency, uremia, infection, hereditary neutrophil hypersegementation, myelokathexisHyposegmentaionPelger–Huet anomaly, lactoferin deficiency, MDS, AMLBotryoid (grape-like) nucleusHeatstroke, hyperthermia, burnsNeutrophil cytoplasmHypogranulationLactoferin deficiency, MDSHypergranulationToxic granulation, pregnancy, infection, inflammation, G-CSF therapy, aplastic anemia, hypereosinophilic syndrome, Alder–Reilly anomaly, chronic neutrophilic leukemia, MDSAbnormal granulesChediak-Higashi syndrome, Alder–Reilly anomaly, MDS, AMLVacuolationInfection, G-CSF therapy, acute alcohol poisoning, Jordan's anomaly, carinitine deficiency, kwashiorkor, myelokathexisDöhle bodies/inclusionsInfection, inflammation, burns, pregnancy, G-CSF therapy, May–Hegglin anomaly, Fechtner syndrome, kwashiorkor, MDS, AML

Normal Neutrophil Cytochemistry

The most reliable method for identifying azurophilic granules on blood films is staining the cells for peroxidase with a myeloperoxidase stain. Production of this enzyme by leukemic cells has been the hallmark for distinguishing lymphoblastic from myeloid leukemia. Chloroacetate esterases appear early in maturation and can be used to detect the origin of immature cells.

Reference Range

The normal range for neutrophils is 2.5–7.5 × 109/L. However, the normal range can vary. People of African and Middle Eastern descent may have lower counts, which are still normal. At birth, the mean neutrophil count rises rapidly to a peak at 12 hours of age, but then drops by 72 hours of age. Thereafter the neutrophil count slowly decreases so that the lymphocyte becomes the predominant cell at two to three weeks of age (DeSantis, 1997). Several perinatal factors may significantly alter neutrophil dynamics including bacterial disease, maternal hypertension, maternal fever prior to delivery, hemolytic disease, and periventricular hemorrhage (Manroe, 1979). A diurnal variation of neutrophil counts has been observed in adults, but not infants. Both neutrophilia and neutropenia are defined using the absolute neutrophil count (ANC). The ANC is equal to the product of the WBC count and the percentage of polymorphonuclear cells (PMNs) and band forms noted on the differential analysis:

The ANC is reported to be as sensitive but more specific than the WBC count as an indicator of occult bacteremia (Gombos, 1998).

Neutrophilia

Definition

Neutrophilia is the presence of more than 20.0 × 103/mm3 neutrophils in the circulating blood. In infants with neutrophilia the ANC is > 10.0 × 103/mm3, in children it is > 8.0 × 103/mm3, and in adults it is > 7.0 × 103/mm3. The term granulocytosis has sometimes been used interchangeably with neutrophilia. In strict terms, granulocytes include neutrophils, eosinophils, and basophils. Total granulocyte count (TGC) is the product of the WBC count and the percentage of PMNs, bands, metamyelocytes, myelocytes, and promyelocytes.

ICD-10 Code D72.8

Pathophysiology

Neutrophilia can be due to a reactive or neoplastic process (Table 1.2). Significant causes of neutrophilia in the neonate can be due to maternal factors (smoking, fever, prolonged oxytocin, and dexamethasone administration) and/or fetal factors (stressful delivery, hypoxia, crying, physiotherapy, pain, hypoglycemia, seizures, infection, hemolysis, intraventricular hemorrhage, meconium aspiration, and hyaline membrane disease).

Table 1.2 Major Causes of Neutrophilia

Acute NeutrophiliaPhysical or emotional stressCold, heat, convulsions, pain, labor, panic, depression, infarction, exercise, postoperative period, following seizures, frequent blood transfusion, acute hemorrhageInfectionsLocalized and system bacterial, rickettsial and spirochetal infectionsInflammation or tissue necrosisBurns, electric shock, trauma, vasculitis, antigen-antibody reaction, complement activationDrugs, hormones, and toxinsSmoking, glucocorticoids, epinephrine, venoms, colony-stimulating factorsChronic neutrophiliaInfectionsPersistence of infections that cause acute neutrophiliaInflammationAcute inflammation involving any organ or systemic such as colitis, nephritis, gout, Sweet's syndromeTumorsCarcinoma, lymphoma, brain tumors, melanoma, multiple myeloma, paraneoplastic reactionDrugsContinued exposure to drugs that cause acute neutrophilia, lithium, rarely drug reactionMetabolic and endocrine disordersEclampsia, thyroid storm, Cushing's disease, gout, diabetic ketoacidosisBenign hematologic disordersSickle cell disease, hemorrhage, recovery from agranulocytosis, aspleniaHematologic neoplasmsMyeloproliferative neoplasmsHereditary and congenitalDown syndrome

Clinical Approach

Reactive causes of neutrophilia are usually part of an inflammatory or infectious course, or can be drug induced. Pharmaceuticals that are commonly associated with neutrophilia are glucocorticoids, growth factors, and psychiatric medications. The reactive causes can have an associated left shift, meaning that the granulocytes in question have more immature forms circulating in the peripheral blood. However, the presence of immature granulocytes can also suggest a neoplastic process. Therefore a substantial history is required to help differentiate the possible source of neutrophilia. Morphologic features that characterize a reactive neutrophilia with or without a left shift are toxic granulation, cytoplasmic vacuolation, and Dohle bodies. The absence of these changes and associated basophilia raises the possibility of neoplasia, particularly myeloproliferative neoplasms. A leukocyte alkaline phosphatase (LAP) score can be used that is high in infection (as well as polycythemia vera) but low in CML and PNH. The LAP score, however, may be normal in polycythemia vera and (juvenile) CML.

Differential Diagnosis

Chronic neutrophilic leukemia, essential thrombocythemia and polycythemia vera are usually associated with an absolute neutrophilia without a left shift. Primary myelofibrosis and chronic myeloid leukemia are usually associated with an absolute neutrophilia and left shift. Performing molecular genetic studies on blood for the bcr/abl and JAK2V617F mutation can help differentiate between myeloid neoplasms and a reactive cause of mature neutrophilia. The differentiation from an acute myeloid leukemia depends on both the cell proliferation and maturity of the cell population. If blasts constitute greater than 20% of the differential or abnormal promyelocytes are identified, further workup for acute leukemia should be pursued.

Neutropenia

Definition

Neutropenia is defined as an ANC below 2.5 × 103/mm3 in infants an ANC below 1.5 × 103/mm3 in adults. However, it is important to be aware that neutrophil counts can be naturally lower in some ethnic groups such as Africans, African Americans, and Yemenite Jews (Tefferi, 2005). An ANC below 0.5 × 103/mm3 is considered to represent severe neutropenia.

ICD-10 Code D70

Pathophysiology

Neutropenia can be caused by decreased production, increased destruction, hereditary disorders, medications, or infections (Table 1.3). The susceptibility to infection in neutropenic patients is related to the ANC. Neutropenia can be classified as follows:

Acquired neutropenia:: Postinfection, drug-induced (e.g., penicillin, chloramphenicol, ibuprofen, phenytoin, propylthiouracil, procainamide, chlorpropamide, phenothiazine), autoimmune (e.g., Felty syndrome, lupus erythematosus), isoimmune (e.g., alloimmune neonatal neutropenia), chronic splenomegaly, benign familial neutropenia, benign neutropenia of childhood, chronic idiopathic neutropenia, and nutritional deficiency.Intrinsic defects:: Cyclic neutropenia, Kostmann syndrome (severe infantile agranulocytosis), myelokathexis (neutropenia with tetraploid or cloverleaf nuclei), Schwachman–Diamond–Oski syndrome, Chédiak–Higashi syndrome, reticular dysgenesis, and dyskeratosis congenita.

Neutropenia is often seen accompanying qualitative neutrophil disorders. Neutropenia is also common in several primary immunodeficiency diseases such as CD40L deficiency, WHIM syndrome (warts, hypogammaglobulinemia, immunodeficiency and myelokathexis), X-linked hyper-IgM, X-linked agammaglobulinemia and Chediak-Higashi syndrome (Rezaei, 2009). Congenital neutropenia includes nonsyndromic variants (caused by mutations in ELA2, HAX1, GFI1, or WAS) and syndromic variants (due to mutations in genes controlling glucose metabolism, e.g., SLC37A4 and G6PC3, or lysosomal function, e.g., LYST, RAB27A, ROBLD3/p14, AP3B1, VPS13B) (Klein, 2009). Defects in genes encoding ribosomal proteins (SBDS, RMRP) and mitochondrial proteins (AK2, TAZ) are also associated with some congenital neutropenia syndromes.

Table 1.3 Major Causes of Neutropenia

AcquiredInfectionAny overwhelming infectionAutoimmune diseaseFelty syndrome, systemic lupus erythematosusComplement activationHemodialysis, filtration leukapheresis acute respiratory distress syndromeDrug-induced neutropeniaClozapine, thionamides, sulfasalazine, Chemotherapeutic agentsToxinsAlcohol, benzeneNon-neoplastic hematologic disordersAplastic anemia, marrow replacement, megaloblastic anemiaHematologic neoplasmsMyelodysplastic syndrome, primary idiopathic myelofibrosis, acute leukemia, T-large granular lymphocytic leukemia, lymphomas with bone marrow involvementCongenitalConstitutionalShwachman–Diamond–Oski syndrome, cyclic neutropenia, Chediak–Higashi syndrome, Kostman syndrome, Fanconi anemia, dyskeratosis

Clinical Approach

In some cases there may be telltale signs that will help you make a diagnosis. For example, vitamin B12 or folate deficiency results in atypical neutrophils that are hypersegmented, whereas aplastic anemia displays a decrease in bone marrow hematopoiesis. However, the underlying diagnosis resulting in neutropenia will typically require a complete history with additional lab testing. Cyclic neutropenia has a very characteristic history of recurrent episodes of fever and neutropenia in a young child. Neutrophils can also have dysfunctional problems, as are discussed later. A bone marrow evaluation can help determine the cellularity of the bone marrow, presence of malignant cells, chromosomal abnormalities suggesting malignant clones, and myeloid nuclear abnormalities. Also, because certain acquired neutropenias may be associated with the presence of antineutrophil antibodies (directed against neutrophil-specific antigens, e.g., NA1, NA2, NB1, ND1, and NE1 and non–neutrophil-specific HLA antigens), their detection (e.g., by immunofluorescence or agglutination assay) may be helpful. Overall, neutropenia is a worrisome occurrence because patients become susceptible to infections when they do not have adequate numbers of neutrophils to respond to an inflammatory and/or infectious assault.

Disorders of Lymphocytes

Normal Lymphocyte Physiology

Lymphocytes differentiate from lymphoblasts into two major types of lymphocytes:

T lymphocytes (T cells): These cells identify foreign substances in your body and begin an immune response;B lymphocytes (B cells): These cells produce antibodies to foreign substances.

Lymphocytes differentiate further after exposure to an antigen. Upon exposure, lymphocytes become effector or memory lymphocytes (Cianci, 2010). The effector B cells release antibodies and effector T cells release cytotoxic granules or send a signal for helper cells (Malaspina, 2007). The memory cells remain in the peripheral blood and retain the ability to respond to the same antigen in the future.

Normal Lymphocyte Morphology

One cannot reliably distinguish functional and immunological lymphocyte subsets by morphology alone. While normal circulating lymphocytes vary in size and shape, they can arbitrarily be divided into small (“mature”) and large (“granular”) lymphocytes (Nguyen, 2000). Mimics of reactive lymphocytes include lymphoma cells, lymphoblasts, monocytes, plasma cells, and nucleated red blood cells.

Mature (Small) Lymphocytes

Mature lymphocytes are approximately the same size as red blood cells (i.e., 7 microns in diameter). They have a prominent nucleus with regular nuclear contours and dense chromatin, and only have a small rim of cytoplasm. Nuclear clefts in small lymphocytes may normally be seen in children. Benign binucleated lymphocytes have been documented in some individuals (Troussard, 1997) and also in association with radiation (Bain, 2002). Rare childhood storage disorders can manifest with prominent cytoplasmic vacuoles in lymphocytes. Inclusions within lymphocytes can be seen in Chédiak–Higashi syndrome, Alder–Reilly anomaly, and Tay–Sachs disease (Bain, 2002). Lymphocyte vacuolation can occur in I-cell disease, the mucopolysaccharidoses, Jordan's anomaly, Niemann–Pick disease, Wolman's disease, Pompe's disease, Tay–Sachs disease, Batten–Speilmeyer–Vogt disease, type II sialidosis, and galactosemia (Bain, 2002).

Reactive Lymphocytes

The term reactive is used to describe transformed benign lymphocytes, and should not be used interchangeably with atypical which should be used to describe malignant-appearing cells (Marty, 1997). Several reactive lymphocyte forms have been described (e.g., Downey classification) (Glassy, 1998). Reactive lymphocytes tend to be larger (9–30 μm) than mature (8–12 μm) lymphocytes. They may also have more abundant basophilic, slightly foamy, or vacuolated cytoplasm. Reactive cells often have an indented surface, which appears scalloped at the edges (Figure 1.11). The nucleus ranges in shape from round to reniform in appearance. Unlike resting small lymphocytes, reactive lymphocytes may have nucleoli. Their nuclear chromatin is typically finer than normal small lymphocytes. Plasmacytoid reactive lymphocytes (sometimes called “plymphs” or Turk cells) resemble plasma cells (Figure 1.12). Plymphs often have a large eccentric nucleus with prominent chromatin clumping, and occasionally a perinuclear hoff may be seen. Reactive lymphocytes that have a plasma cell-like appearance are usually seen as part of a heterogeneous mix of reactive lymphoid cells. They likely represent intermediate B lymphocytes differentiating into plasma cells. Reactive lymphocytes enlarge due to antigen stimulation. More recent studies suggest that reactive lymphocytes are activated T lymphocytes produced in response to infected B lymphocytes (Thomas, 2008). They act as normal lymphocytes in sites of local inflammation, playing a role in the primary cellular immune or helper T-cell response (Simon, 1997).

Figure 1.11Reactive lymphocyte in a patient with infectious mononucleosis (monospot test positive). The large reactive lymphocyte shown corresponds to a so-called Downey type II cell. These cells have an abundant pale gray-blue amoeboid cytoplasm that partially surrounds adjacent erythrocytes. The curled edges against the RBCs and radiating cytoplasm are slightly darker staining.

Figure 1.12Plasmacytoid appearing reactive lymphocyte with coarse chromatin and an eccentric nucleus.

Large Granular Lymphocytes (LGLs)

LGLs are large (T-cell phenotype) lymphocytes with azurophilic granules that contain proteins involved in cell lysis, such as perforin and granzyme B. LGLs normally comprise 10 to 20% of the total lymphocyte population (Nguyen, 2000). Monocytes by comparison contain smaller granules and have a ground-glass cytoplasm.

Natural Killer (NK) Cells

NK cells are a third type of lymphocyte; they are similar to cytotoxic T cells and LGLs, which cause cell lysis of tumor cells and virus-infected cells by releasing granzyme B. NK cells were named as such because they do not require antigen priming to destroy abnormal self-cells. Therefore the cytoxic affect occurs naturally (Morice, 2007). These cells have a large granular lymphocyte appearance; however, NK cells do not display T-cell receptors or pan-T markers (CD3).

Normal Lymphocyte Immunophenotype

In general, T lymphocytes are CD3 positive and individually display CD4 or CD8 staining. Few lymphocytes display both CD4 and CD8 positivity. T-cell LGLs exhibit CD8 and variable CD11b, CD56, and CD 57 positivity. Granzyme B can also be used for T-cell LGL identification (Table 1.4). B lymphocytes display CD20 and CD79a, and are also positive for CD19 on flow cytometry. Plasma cells do not express many surface antigens and are negative for the B cell markers CD19 and CD20 (Table 1.5). They are identified by CD38 and CD138 staining. Natural killer cells display CD16 (FcγRIII), CD56, CD57, CD2, and granzyme B.

Table 1.4 T-Cell Phenotype During Stages of Maturation

Table 1.5 B-Cell Phenotype During Stages of Maturation

Lymphocytosis

Definition

Lymphocytosis is defined as the presence of more than 4 × 103/mm3 lymphocytes in the circulating blood in adults, more than 7 × 103/mm3 in children, and more than 9 × 103/mm3 in infants.

ICD-10 Code D72.8

Pathophysiology

Lymphocytosis can be divided into reactive and neoplastic etiologies. Table 1.6 lists some common causes of lymphocytosis. Reactive lymphocytosis is most commonly associated with acute viral illnesses such as infectious mononucleosis due to Epstein Barr virus (EBV) (Nkrumah, 1973; Marty, 1997; Peterson, 1993). Lymphocytosis can also occur with other infections like whooping cough (Kubic, 1990). Reactive lymphocytosis secondary to stress (e.g., myocardial infarction, sickle cell crisis, and trauma) may be more transient (Groom, 1990; Karandikar, 2002).

Table 1.6 Major Causes of Lymphocytosis

Reactive causes of lymphocytosisAcute viral infectionsInfectious mononucleosis (Epstein Barr virus), cytomegalovirus, HIV, hepatitis, adenovirus, chickenpox, herpes simplex and zoster, influenza, mumps, measlesAcute bacterial infectionsPertussis (whooping cough), brucellosis, tuberculosis, typhoid fever, paratyphoid feverProtozoan infectionsToxoplasmosis, Chaga's diseaseChronic bacterial infectionsTuberculosis, brucellosis, syphilisAutoimmune diseaseRheumatoid arthritis, idiopathic thrombocytopenic purpura, systemic lupus erythematosus, autoimmune hemolytic anemiaDrug and toxic reactionsDilantin, dapsone, lead, organic arsenicsEndocrine causesStress, Addison's disease, glucocorticoid deficiency, thyrotoxicosisMiscellaneousDuring recovery from acute infections (especially in children), allergic reactions, malnutrition, ricketsNeoplastic causes of lymphocytosisAcute lymphoblastic leukemiaNon-Hodgkin lymphomaT-cell large granular lymphocytic leukemia (T-LGL)

Clinical Approach

Lymphocytosis is particularly common in children with infection. In viral-induced lymphocytosis there is typically a mixed population of reactive cells, including small lymphocytes, plasmacytoid cells, and few larger lymphocytes. The minimal morphologic criteria for the diagnosis of infectious mononucleosis are (1) 50% or more mononuclear cells (lymphocytes and monocytes) in a blood smear, (2) at least 10 reactive lymphocytes per 100 leukocytes, and (3) marked lymphocyte heterogeneity (Peterson, 2006). Increased numbers of apoptotic lymphocytes are often seen with viral infections. In the elderly population, lymphocytosis is more concerning to be secondary to a neoplastic or lymphoproliferative disorder such as leukemia or lymphoma. Large granular lymphocytes will occur in increased number in large granular lymphocytic leukemia (T-LGL), which can mimic a reactive process and is thus frequently underdiagnosed. T-LGL is known to be associated with several autoimmune and hematologic conditions including myelodysplastic syndromes. Therefore it is important to keep T-LGL in the differential diagnosis of a reactive lymphocytosis. Lymphocytosis after splenectomy is usually mild, and will be accompanied by the presence of Howell–Jolly bodies (Juneja, 1995). Morphological criteria alone may be insufficient to distinguish reactive from malignant lymphocytes. In such cases immunophenotyping (e.g., flow cytometry) and molecular studies (e.g., PCR for IgH gene rearrangement) may be needed.

Lymphocytopenia

Definition

Lymphocytopenia is defined as the presence of less than 1.0 × 103/mm3 lymphocytes in the circulating blood in adults. Children have higher normal levels of lymphocytes, and lymphocytopenia is defined as less than 2.0 × 103/mm3.

ICD-10 Code D72.8

Pathophysiology

Lymphocytopenia can be secondary to congenital immunodeficiency disorders or a reactive process to underlying disease (Table 1.7).

Table 1.7 Major Causes of Lymphopenia

Reactive causes of lymphocytopeniaInfectious diseasesHIV, influenza, hepatitis, tuberculosis, babesiosis, pneumonia, sepsisAutoimmune disordersRheumatoid arthritis, myasthenia gravis, systemic lupus erythematosusNutritional disordersZinc deficiency, protein malnutritionSystemic diseasesRenal insufficiency, sarcoidosis, carcinoma, Hodgkin lymphomaIatrogenic causesRadiation therapy, burnsMedications