Haem 6 - Abnormal white cell count Flashcards
Define haematopoiesis
Production of BC in the bone marrow
Describe normal haemopoiesis
Polyclonal healthy/reactive
- Normal marrow
- Reactive marrow (during infection)
Describe malignant haemopoiesis
Abnormal/clonal
- Leukaemia (lymphoid, myeloid), myelodysplasia, myeloproliferative
Draw the diagram for normal haematopoiesis
See diagram
Myeloid stem cells - maturation only occurs in the bone marrow.
Describe the differentiation & maturation of a neutrophil?
See diagram
Bone marrow
1) Myeloblast
2) Promyelocyte
3) Myelocyte
4) Metamyelocyte
Pheripheral blood
5) Neutophil
What cytokines control the cell numbers for erythroid, lymphoid and myeloid cells
Erythroid - Erythropoietin
Lymphoid - IL-2
Myeloid - G-CSF, M-CSF
What do cytokines do in terms of haematopoiesis?
Influences differentiation and proliferation.
If it is DNA directed differentiation and proliferation = DNA damage –> cancer (leukaemia/lymphoma/myeloma)
What two classes of WBC fall under leucocytes?
lymphocytes and phagocytes
What do lymphoblasts differentiate to?
T lymphocytes
B lymphocytes
NK cells
What do phagocytes differentiate to?
Granulocytes - Neutrophils, Eosinophils, basophils
Monocytes
What is the basis of abnormal WBC?
Its the balance between cell production and cell survival
See diagram
What would cause an increase in WBC production?
Reactive
- Infection
- Inflammation
Malignant
- Leukaemia (haematopoeitic cancer)
- myeloproliferative
What would cause a decrease in WBC production?
Impaired BM function
- B12 or Folate deficiency
- BM failure
1) Aplastic anaemia
2) Post chemotherapy
3) Metastatic cancer
4) Haematological cancer
What would cause an increase in WBC survival?
Failure of apoptosis (e.g acquired cancer causing mutations in some lymphomas)
What would cause a decrease in WBC survival?
Immune breakdown
Describe what happens during haemopoietic cancers?
Haemopoietic cancers (leukaemia) produce immature and mature cells which go into the peripheral blood. In normal WBC proliferation and differentiation immature cells proliferate and differentiate from stem cells in the bone marrow. Then the mature cells are released into the peripheral blood that respond to infection.
What are two causes of Eosinophilia?
Reactive (parasitic infection)
Primary (malignant - myeloproliferative disorder)
What is normal haematopoiesis stimulated by?
1) Inflammation
2) Infection
3) Increased cytokine production
- Distant tumour
- Haemopoietic or non haemopoietic
What can cause abnormal haematopoiesis?
(autonomic cell growth)
1) Cancers of haematopoietic cells
2) Leukaemia
- Myeloid or lymphoid
- Chronic or acute
3) Myeloproliferative disorders
Describe Malignant haemoatopoiesis?
See diagram
How do you investigate a raised WCC?
History and examination
Haemoglobin and platelet count
Automated differential
Examine blood film
Abnormality White cells only, or all 3 lineages (red cells/platelets/white cells) ?
White cells 1 cell type only, or all lineages? (e.g. neuts/eos/monocytes/lymphocytes)
Mature cells only or mature and immature cells?
If there are elevated levels of immature WBC what can that suggest?
Blastocytes + low Hb + low platelets –> Acute leukamia
If there are elevated levels of mature + immature WBC what can that suggest?
Neutrophils + Myelocytes + basophils –> Chronic myeloid leukaemia
If there are elevated levels of mature cells what can that suggest?
All lineages or only one (neuts, eos, baso) –> reactive/infection
Lymphocytes –> reactive (viral) or primary (chronic lymphocytic leukaemia)