Leukemias Overview and Classification

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Questions and Answers

What is the primary cause of Lysosomal Storage Disorders?

Infection of lysosomes

Autoimmune responses targeting lysosomal enzymes

Inherited enzyme deficiencies (correct)

Environmental factors affecting enzyme activity

Which of the following macromolecules accumulates in Mucopolysaccharidoses due to enzyme deficiency?

Fatty acids

Proteins

Nucleic acids

Mucopolysaccharides (correct)

What distinctive feature is associated with Gaucher cells?

Absence of cytoplasmic granules

High levels of lysosomal enzyme activity

Irregular nuclear shape

Presence of lipid-filled foamy cytoplasm (correct)

Which enzyme is deficient in Gaucher Disease?

b-glucocerebrosidase Signup and view all the answers

What type of cells are characterized as foam cells in Niemann-Pick Disease?

Macrophages with lipid-filled lysosomes Signup and view all the answers

WHIM Syndrome is primarily associated with which of the following conditions?

Catalase-positive infections Signup and view all the answers

What is the primary genetic mutation linked to WHIM Syndrome?

CXCR4 gene Signup and view all the answers

In Pelger-Huët Anomaly, what characteristic morphology do the leukocyte nuclei often display?

Bilateral spectacle-like forms Signup and view all the answers

Which of the following best describes the cell type primarily affected in pseudo-Pelger-Huët Anomaly?

Neutrophils primarily Signup and view all the answers

Hypersegmented neutrophils are typically associated with which type of anemia?

Megaloblastic anemia Signup and view all the answers

Which of the following disorders is characterized by large, darkly staining metachromatic cytoplasmic granules in granulocytes?

Alder-Reilly Anomaly Signup and view all the answers

Hypogammaglobulinemia is a characteristic finding in which syndrome?

WHIM Syndrome Signup and view all the answers

What percentage of leukocytes is typically affected in true Pelger-Huët Anomaly?

<blockquote> 68% </blockquote> Signup and view all the answers

What genetic mutation is primarily associated with Wiskott-Aldrich Syndrome?

Mutation in the WAS gene Signup and view all the answers

Which syndrome is specifically characterized by a microdeletion in chromosome band 22q11.2?

DiGeorge Syndrome Signup and view all the answers

What is the primary consequence of Bruton Tyrosine Kinase Deficiency?

Absent T cells and low immunoglobulin isotypes Signup and view all the answers

What is the genetic basis of Chédiak-Higashi Syndrome?

Mutation in the CHS1 LYST gene Signup and view all the answers

Which type of deficiency is characterized by the inability of neutrophils to migrate properly?

Leukocyte Adhesion Disorders Signup and view all the answers

Which syndrome is associated with congenital neutropenias and a risk of leukemic transformation?

Congenital Defects of Phagocytes Signup and view all the answers

What primary defect characterizes Shwachman-Diamond Syndrome?

Leukocyte motility defect Signup and view all the answers

What is the effect of Chronic Granulomatous Disease on neutrophils?

Decreased ability to undergo respiratory burst Signup and view all the answers

What characteristic distinguishes FAB L2 from other ALL subtypes?

Large lymphoblast with an irregular cleft nucleus Signup and view all the answers

In which type of leukemia is the Philadelphia chromosome notably absent?

Chronic Lymphocytic Leukemia (CLL) Signup and view all the answers

What is the most common form of ALL in children?

FAB L1 Signup and view all the answers

What specific markers are associated with Hairy Cell Leukemia?

CD19, CD20, CD22 Signup and view all the answers

Which chromosomal abnormality is associated with FAB L3?

T(8,14) Signup and view all the answers

What age group is primarily affected by Chronic Myeloid Leukemia (CML)?

Middle-aged adults Signup and view all the answers

What type of malignancy is Mycosis Fungoides classified as?

Cutaneous T-cell lymphoma Signup and view all the answers

Which of the following statements about CLL is true?

It is a disease of mainly B-cells, with some T-cell involvement. Signup and view all the answers

What is the primary genetic defect in X-linked Severe Combined Immune Deficiency (SCID)?

Mutations in the IL2RG gene Signup and view all the answers

Which disorder is characterized by a marked decrease in circulating T cells and poorly functioning B cells?

Severe Combined Immune Deficiency Signup and view all the answers

What defines Chediak-Higashi syndrome regarding leukocyte function?

Abnormal lysosomal trafficking in leukocytes Signup and view all the answers

What is a significant peripheral blood finding in chronic lymphocytic leukemia?

Lymphocytosis Signup and view all the answers

Which clinical manifestation is associated with Adenosine Deaminase (ADA) deficiency?

Skeletal abnormalities Signup and view all the answers

Which of the following best describes the characteristic morphology of Macrophages in Niemann-Pick disease?

Foamy cytoplasm due to lipid accumulation Signup and view all the answers

What is a key feature of acute myeloid leukemia that differentiates it from acute lymphoblastic leukemia?

Myeloblasts in peripheral blood Signup and view all the answers

Which type of leukemia is particularly noted for presenting with hairy cells in the peripheral blood?

Hairy cell leukemia Signup and view all the answers

Study Notes

Acute Lymphoblastic Leukemia (ALL)

A genetically heterogeneous clonal disorder of myeloid lineage.
Increases in the number of immature cells due to hematopoietic insufficiency with or without leukocytosis.
Most common in children, less common in adults.

Acute Myeloid Leukemia (AML)

A clonal disorder of myeloid lineage.
Increased number of immature myeloid cells.
Most common in adults.

FAB Classification (Subgroup ALLs)

L1: Small lymphoblast with regular nucleus, most common in children.
L2: Large lymphoblast with irregular nucleus, most common in adults.
L3: Leukemic phase of Burkitt's Lymphoma with large, homogenous, and vacuolated lymphoblast with round or oval nucleus.

ALL Classification (WHO - World Health Organization)

B-cell lineage: Precursor B lymphoblastic leukemia/lymphoblastic lymphoma (B-ALL)
T-cell lineage: Precursor T lymphoblastic leukemia/lymphoblastic lymphoma (T-ALL)

Chronic Lymphocytic Leukemia (CLL)

Most often occurs in older adults, primarily affects B-cells (some T-cells).
Absence of Philadelphia chromosome.
Characterized by smudge cells and JAK2 V617K gene positivity.

Chronic Myelogenous Leukemia (CML)

T(9,22) BCR/ABL gene mutation (Philadelphia chromosome).
Decreased LAP score and JAK2 V617F gene negativity.
Most common in middle-aged adults.

Hairy Cell Leukemia

TRAP positive B-cell malignancy.
CD markers: CD19, CD20, CD22.
Most specific markers: CD123, ANNEXIN A1.

Mycosis Fungoides

Most common cutaneous lymphoma.
T-cell malignancy.
Presence of Sezary cells.

Severe Combined Immune Deficiency (SCID)

Group of genetic immunodeficiencies affecting both cellular and humoral immunity.
Marked decrease in circulating T-cells, poorly functioning B-cells, hypogammaglobulinemia, and profound clinical manifestations.

Gamma Chain Deficiency

X-linked SCID (most common form of SCID).
Caused by mutations in the IL2RG gene.
IL2RG codes for the common gamma chain in leukocyte receptors that bind with interleukins 2, 4, 7, 9, 15, and 21
Circulating T and natural killer (NK) lymphocytes are nearly absent.
B cells are adequate in number but are dysfunctional.

ADA Deficiency

Autosomal recessive adenosine deaminase deficiency.
Key component of the metabolic breakdown of adenosine triphosphate and RNA.
Profound decreases in T, B, and NK cells.
Skeletal abnormalities, neurologic deficits, and skin rashes.

Wiskott-Aldrich Syndrome

Rare X-linked disease caused by mutations in the WAS gene.
WASp is important in cytoskeletal remodeling and nuclear transcription in hematopoietic cells.
T cells are decreased, B cells, T cells and NK cells, neutrophils and monocytes are dysfunctional.

22q11 Syndromes

A microdeletion in chromosome band 22q11.2, most likely involving TBX1.
Includes DiGeorge syndrome, autosomal dominant Opitz GBBB, Sedlackova syndrome, Caylor cardiofacial syndrome, Shprintzen syndrome, and conotruncal anomaly face syndrome.
Variable degrees of immunodeficiency due to the absence or decreased size of the thymus and low numbers of T lymphocytes.

Bruton Tyrosine Kinase Deficiency

Classifies as an antibody deficiency.
Reductions in all serum immunoglobulin isotypes and profoundly decreased or absent B cells.

Chédiak-Higashi Syndrome

A rare autosomal recessive disease of immune dysregulation.
Mutation in the CHS1 LYST gene on chromosome 1q42.1-2, which encodes for a protein that regulates the morphology and function of lysosome-related organelles.
Many types of cells in the body are affected and exhibit abnormally large lysosomes, which contain fused dysfunctional granules.

Congenital Neutropenias (CNs)

Rare group of genetic diseases characterized by low neutrophil count, increased risk of infection, organ dysfunction, and a high rate of leukemic transformation.

Leukocyte Adhesion Disorders (Defects of Motility)

Rare autosomal recessive inherited conditions resulting in the inability of neutrophils and monocytes to move from circulation to the site of extravasation.
LAD I - B2 Integrin
LAD II - Selectin synthesis
LAD III - Kindlin 3

Shwachman-Diamond Syndrome (SDS)

Defect in leukocyte motility.
Rare autosomal recessive disease caused by mutations in the SBDS gene.

Defects of Respiratory Burst

Chronic granulomatous disease (CGD) is a rare condition caused by the decreased ability of neutrophils to undergo a respiratory burst after phagocytosis of foreign organisms.
Patients experience life-threatening catalase-positive bacterial and fungal infections.

WHIM Syndrome (warts, hypogammaglobulinemia, infections, and myelokathexis syndrome)

Classifies as a defect in intrinsic and innate immunity.
Mutations in the CXCR4 gene
Regulates movement of white blood cells between the bone marrow and peripheral blood.
Neutropenia, lymphopenia, monocytopenia, and hypogammaglobulinemia are present.

Pelger-Huët Anomaly (PHA)

Also known as true or congenital PHA.
Decreased nuclear segmentation and distinctive coarse chromatin clumping pattern.
Affects all leukocytes.
Mutation in the lamin beta-receptor gene.

Pseudo- or Acquired Pelger-Huët Anomaly

Neutrophils with similar morphology to PHA can be seen in patients with MDS, acute myeloid leukemia, and myeloproliferative neoplasm.
Acquired or pseudo-PHA neutrophils are also associated with severe bacterial infections, HIV, tuberculosis, and mycoplasma pneumonia.

Neutrophil Hypersegmentation

Hypersegmented neutrophils have more than five lobes and are most often associated with megaloblastic anemia, in which hypersegmented neutrophils are usually larger than normal.

Alder-Reilly Anomaly

A rare inherited disorder characterized by granulocytes (monocytes and lymphocytes less often) with large, darkly staining metachromatic cytoplasmic granules.
Initially reported in patients with gargoylism.

May-Hegglin Anomaly

A rare, autosomal dominant disorder characterized by variable thrombocytopenia, giant platelets, and large Döhle body-like inclusions in neutrophils, eosinophils, basophils, and monocytes.
Mutation in the MYH9 gene on chromosome 22q12-13.3.

Lysosomal Storage Disorders

Group of more than 50 inherited enzyme deficiencies resulting from mutations in genes that code for the production of lysosomal enzymes.
Classified according to the under degraded macromolecule that accumulates in the cell.

Mucopolysaccharidoses

Family of inherited disorders of mucopolysaccharide or glycoaminoglycan (GAG) degradation.
Deficient activity of an enzyme necessary for the degradation of dermatan sulfate, heparan sulfate, keratan sulfate, and/or chondroitin sulfate.

Gaucher Disease

Most common of the lysosomal lipid storage diseases.
Caused by a defect or deficiency in the catabolic enzyme b-glucocerebrosidase.
Bone marrow replacement by Gaucher cells contribute to anemia and thrombocytopenia.
Gaucher cells are distinctive macrophages, single or in clusters, exhibiting abundant fibrillar blue-gray cytoplasm with a striated or wrinkled appearance.

Niemann-Pick Disease

Characterized by an accumulation of fat in cellular lysosomes of vital organs.
Foam cells and sea-blue histiocytes can be seen in the bone marrow.
Foam cells are macrophages with cytoplasm packed with lipid-filled lysosomes that appear as small vacuoles (foam) after staining.
Sea blue histiocytes are macrophages with lipofuscin-, glycophospholipid-, and sphingomyelin contained in -cytoplasmic granules, 1 to 3 m in diameter, that appear blue with Wright stain.

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Description

This quiz explores various types of leukemia, including Acute Lymphoblastic Leukemia (ALL) and Acute Myeloid Leukemia (AML). It covers their classifications, characteristics, and age prevalence. Test your understanding of the different forms and subtypes of leukemia.