Abnormal White Cell Count Flashcards
(44 cards)
What is pancytopenia?
all cell lineages reduced
In normal haemopoiesis, are the cells clonal or polyclonal?
polyclonal - different types but there is one original
What are characteristics of malignant haemopoiesis?
abnormal and clonal population
Describe the differentiation pathway for T cell and B cell formation?
HSC -> Pre T/B -> B/T cell
What regulates haematopoeisis?
many cytokines and growth factors
What are the two types of progenitors the HSC can develop into?
Common myeloid/lymphoid progenitor
What can a CMP develop into?
CMP -> myeloblast, mast cell, erythrocyte, megakarcoyte (-> platelet)
What can a myeloblast become?
myeloblast -> basophil, neutrophil, eosinophil, monocyte (-> macrophage)
What is a myeloblast?
very large cell with a high nucleus:cytoplasmic ratio β not many granules
During myeloid maturation there are many stages, name some of them
myeloblast, promyelocyte, myelocyte, metamyelocyte -> neutrophil for example
What are myeloid cells?
Everything that develops from a common myeloid progentior so everything but lymphocytes (includes natural killer cells)
What is a promyelocyte?
They are very large cells, with heavy granulation in the cytoplasm
What is a myelocyte?
Cells in which the nucleus becomes eccentric and the cytoplasm becomes smaller
In the peripheral blood in a healthy person should differentiating cells be seen?
When may they be seen?
no
- In septic patients β the bone marrow starts to release very immature cells
- In patients receiving chemotherapy β white cell count falls
- In chronic myeloid leukaemia -> presence of cells at all stages of myeloid differentiation in the blood
What is seen in septic patients in terms of blood cells?
- We find a leukoerythroblastic picture
- This described the presence of myeloid precursors with nucleated red cells
- This shows that the bone marrow is trying to compensate for the peripheral destruction of cells
In patients having chemotherapy, why are immature myeloid cells seen in the blood?
- White cell count falls
- Hence we give these patients the growth factor G-CSF β stimulates bone marrow to release more white cells
What is seen in chronic myeloid leukaemia?
- Presence of cells at all stages of myeloid differentiation in the blood
Which factors mediate the developemt of erythroid, lymphoid and myeloid cells?
Erythroid cells -> erythropoietin produced in the kidneys
Lymphoid cells -> IL2, along with other cytokines
Myeloid cells -> G-CSF and M-CSF growth factors
Which immature cells should not be seen in peripheral blood and only in bone marrow?
lymphoblasts, myeloblasts, promyelocytes, myelocytes and metamyelocytes
What can cause abnormal white blood cell production?
- REACTIVE (you get increased production during infection and inflammation)
- MALIGNANT (increased WBC count in leukaemia and can be myeloproliferative)
- IMPAIRED BM FUNCTION (reduced WBC count when bone marrow function is impaired)
- BM FAILURE (reduced WBC in aplastic anaemia, chemotherapy, metastatic/haematological cancer)
- B12 OR FOLATE DEFICIENCY (reduced WBC count
What are myeloproliferate neoplasms?
A group of rare disorders of the bone marrow that cause an increase in the number of blood cells. Used for both malignant and non cancerous tumours.
What can cause abnormal white cell survival?
- FAILURE OF APOPTOSIS (increased survival in cancer causing mutations in some lymphomas)
- IMMUNE BREAKDOWN (decreased survival in autoimmune breakdown of WBCs by antibodies)
What are the two main factors that lead to an abnormal white cell count?
abnormal white cell production and abnormal white cell sruvival
What are the two causes of eosinophilia?
- REACTIVE CAUSES OF EOSINOPHILIA where haemopoiesis is normal:
- Inflammation
- Infection (parasites)
- Increased cytokine production (due to a distant tumour) - PRIMARY (MALIGNANT) CAUSES OF EOSINOPHILIA where haemopoiesis is abnormal:
- Cancers of haematopoietic cells
- Leukaemia
- Myeloproliferative disorders