Haematologia

Hematopathology Lecture Outline

• Purpose: Aid students in note-taking during lectures.

• Exam Relevance: Not all information presented is necessary for the exam; some are for complexity or interest.

Preparations and Exam Topics

Primary Exam Topics

1. Burkitt’s lymphoma

2. Lymphomatous polyposis

3. Multiple myeloma

4. CML - splenomegalia

Additional Topics

1. Toxoplasma lymphadenitis

2. Follicular lymphoma

3. CLL/SLL in lymph node

4. Diffuse large B-cell lymphoma

5. Hodgkin’s lymphoma

6. CML, CP, smear

Further Examination Areas

• Reactive lymph node changes

• Indolent B-cell lymphomas: FL, CLL, MCL, MZL

• High-grade B cell lymphomas: BL, DLBCL

• Plasma cell neoplasms

• Hodgkin’s lymphoma

• T/NK cell lymphomas

• Non-neoplastic bone marrow diseases

• AML and MDS

• Myeloproliferative neoplasms

Hematopoiesis

• Production Rates:

  • Leukocytes: 60 × 10^9 /day

  • RBCs: 210 × 10^9 /day

  • Thrombocytes: 140 × 10^6 /day

Normal Blood Ranges

• Neutrophil: 1.8 – 5.4 × 10^9

• Eosinophil: 0.0 – 0.5 × 10^9

• Basophil: 0.0 – 0.08 × 10^9

• Monocyte: 0.3 – 0.8 × 10^9

• Lymphocyte: 1.3 – 3.6 × 10^9

• RBC: 4.5 – 6 × 10^12

• Thrombocyte: 140 – 440 × 10^9

Hematopoiesis Lineage

Lineage Progression Overview

• CMP: Common Myeloid Progenitor

• MEP: Megakaryocyte-Erythroid Progenitor

• GMP: Granulocyte-Macrophage Progenitor

• Lymphoid Cell Populations: B-cell, T-cell, NK-cell, Dendritic Cell

• Stem Cell Types: ST-HSC (Short-term HSC), LT-HSC (Long-term HSC)

Hematopoietic Pathways

• Active LT-HSC: Hematopoiesis, Monocyte/Macrophage, Mast Cell, Basophil, Eosinophil, Neutrophil, Erythrocyte, Thrombocyte, B-cell, T-cell, NK-cell

Lymphoid Characters and Development

B-Lymphoid Lineage

• Stages: pro-B, pre-B, immature B-cell, to mature naive B-cell, activated B-cell.

• Genetic Rearrangements:

  • Terminal deoxynucleotidyl transferase (TdT), V-D-J recombination.

  • Immunoglobulin types: IgM + IgD.

T-Lymphoid Lineage

• Stages: pro-T, pre-T, CD4+/CD8+, Treg cells, Th1, Th2, Cytoxic T-cells.

• Genetic Rearrangements: TCR gene rearrangement.

Lymphocyte Differentiation and Maturation

• TCR/BCR Rearrangement

• Positive and Negative Selection of T-cells

• Activation Signals: Costimulation vs. Anergy

Lymphocyte Populations and Function

B-cell Subtypes

• B1 B-cells: Innate function, spontaneous IgM production.

• Marginal Zone B-cells: T-cell independent activation, low affinity antibodies.

• Follicular B-cells: T-cell dependent mechanisms, high affinity antibodies.

T-cell Subtypes

• CD4+ (helping) and CD8+ (cytotoxic) T-cells,

• NKT-cells: Role in innate immunity, cytolytic functions.

Lymphatic Tissue Abnormalities

General Terms

• Lymphadenopathy: Enlargement of lymph nodes.

• Lymphadenomegaly: Enlargement of nodes due to various causes.

• Lymphadenitis: Inflammation of lymph nodes.

Clinical Characteristics for Diagnosis

• Localized vs. Generalized

• Painful vs. Painless

• Soft vs. Firm/Hard

• Rapid Growth vs. Stable

Differential Diagnosis

• Reactive Changes/Infection

• Hematologic Malignancies

• Metastatic Disease

Reactive Lymph Node Abnormalities

Types of Changes

1. Non-specific: follicular hyperplasia, paracortical hyperplasia, sinus histiocytosis.

2. Specific: Toxoplasma lymphadenitis, Infectious Mononucleosis.

Clinical Implications

• Indicate possible infection, autoimmune conditions, or hematologic malignancies.