Laboratory Diagnosis of Neoplastic and Nonneoplastic Leukocytic Disorders

These flashcards cover key concepts related to the laboratory diagnosis of neoplastic and nonneoplastic leukocytic disorders, focusing on hematopoiesis, leukocyte disorders like neutrophilia and neutropenia, and specific leukemias.

What is hematopoiesis and where does it occur postnatally in humans?

Hematopoiesis is the production of blood cells, which occurs primarily in the bone marrow postnatally.

What types of progenitor cells arise from multipotent progenitors in hematopoiesis?

Common myeloid progenitors and common lymphoid progenitors.

Which factors regulate the proliferation and differentiation of hematopoietic precursor cells?

Hematopoietic growth factors and interleukins (e.g., IL-3, IL-5, IL-6, IL-9, IL-11).

What is neutrophilia?

An absolute concentration of neutrophils in the blood above normal for age.

What is the normal range of neutrophil count for adults?

Approximately 1.8-7.0 x 10^3/μL.

Name two causes of neutrophilia.

Acute infection and physiological stresses like exercise or pregnancy.

What is neutropenia?

A reduction in the absolute neutrophil count (ANC) below 1.5-2 x 10^9/L for white adults.

What are some mechanisms that lead to neutropenia?

Decreased production in marrow, increased removal from blood, altered distribution, or a combination of these mechanisms.

What alterations can occur morphologically in neutrophils?

Toxic granulation, cytoplasmic vacuoles, Döhle bodies, and various anomalies like Pelger-Huet.

What do eosinophils primarily respond to?

Immunologic stimuli and they participate in allergic reactions and destroy helminths.

What is monocytosis?

An increase in monocytes above the upper reference value, especially when greater than 1.0 x 10^9/L.

What is the primary function of macrophages derived from monocytes?

Defense against microorganisms, processing antigens, and antibody-dependent cellular cytotoxicity.

What is basophilia?

An increase in the absolute basophil count above 0.2 x 10^9/L.

Describe the training process for B cells during development.

B cell differentiation occurs in two stages; the first is antigen-independent generation of diversity through Ig gene rearrangement, the second is regulated by antigen and other factors.

What is the clinical significance of lymphocytosis?

Lymphocytosis is an increase in lymphocyte count in the blood, often seen in viral infections.

What are common causes of lymphocytopenia?

Immunologic deficiency disorders, increased adrenocortical hormones, and chemotherapeutic agents.

What characterizes Chronic Myelogenous Leukemia (CML)?

CML features an increase in leukocyte count, a spectrum of granulocytic cells, and often the Philadelphia chromosome abnormality.

How is Acute Myeloid Leukemia (AML) diagnosed?

Requires the presence of 20% blasts in the marrow or blood.

What laboratory tests are significant in diagnosing Acute Lymphoblastic Leukemia (ALL)?

Presence of blasts with characteristic immunophenotype using flow cytometry.

What distinguishes chronic lymphocytic leukemia from other leukemias?

Clonal proliferation of small B lymphocytes with typical appearances and often no anemia or thrombocytopenia.