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White blood cells.
Normal and malignant.
Question | Answer |
---|---|
Simplify FBC testing. | Instruments are essentially particle counters with additional test to determine type of cells. |
What are scatterplots? | A graphical representation of electronic data generated by the laser/cell interaction. |
What does each coloured area (and dotted area) on a scattergram represent? | A reportable parameter (the dotted regions indicate flagging areas). |
What are automated WBC differential and blood films useful for? | Evidence of and response to infection. Allergic response. Leukemia. Marrow infiltration. |
What can flow cytometry show? | Lymphoid and myeloid populations and degree of cell maturity. |
What is cytogenetics? | Metaphase analysis and flourescent in-situ hybridisation. |
Why would gene sequencing be used? | To look for specific mutations. |
Why would a bone marrow examination be used? | To assess the number and type of normal and abnormal cells. |
What happens to bone marrow with age? | At birth marrow is widely distributed, retreating to axial skeleton by adulthood. |
What happens to embryonic stem cells? | Embryological stem cells form "blood islands" in the yolk sac. Cells migrate to liver then spleen then marrow in foetus. |
What is the stroma of bone marrow composed of? | Fibroblast-like reticular cells, collagenous fibres and extracellular matrix. |
What is the commonest of the WBCs? | Neutrophils (50-70% of the total). |
What is the lifespan of neutrophils? | 8-10 hours. |
What is chemotaxis? | When neutrophils migrate in response to e.g. bacterial wall antigens. |
How do neutrophils contrast with lymphocytes? | They do not recognise specific antigens. |
How do neutrophils deal with bacteria? | Bacteria are ingested and killed by enzymes in granules e.g. lysozyme, peroxidase. |
When to neutrophil numbers change? | Rise as acute response to bacterial infection, inflammation and malignancy. |
What are the three types of Granulocytes? | Basophils, Eosinophils and Neutrophils. |
How much of the total blood WBC do eosinophils make up? | 1-6%. |
What colours does eosin stain the granules? | Orange/pink. |
What is the lifespan of eosinophils? | 4-5 hours (longer in tissues). |
What promotes the growth of eosinophils? | Interleukin-5. |
What is contained in the eosinophil granules? | Major basic protein and reactive O2 species. |
What do eosinophils respond to? | Helminth infection. Chemokines attract them to specific tissues. |
Where are eosinophils commonly found? | Commonly seen in atopy e.g. eczema, asthma and hayfever. |
What is a basophil an example of? | A granulocyte. |
What proportion of the total blood WBCs do basophils make up? | <1%. |
What do dark basophilic granules contain? | Histamine, leukotrienes, proteases and heparin. |
What are the roles of basophils? | Phagocytosis and in hypersensitivity (allergic) reaction. |
What is the cell surface receptor on a basophil for? | Cell surface receptor for IgE-binding produces degranulation following chemotaxis. |
What is anaphylaxis? | A type 1 allergic reaction. |
What proportion of blood WBCs do lymphocytes make up? | 20-40%. |
How can we subdivide lymphocytes? | They differentiate early from other marrow derived cells. Divide into T (thymus) and B (bone marrow or bursa). |
What increases the lifespan of a lymphocyte? | Much longer life span in blood/marrow and lymph node. |
What can T and B cell malignancies cause? | Leukemia. |
What proportion of circulating blood cells do monocytes/macrophages make up? | 5-10%. |
What do macrophage granules contain? | Hydrolases and myeloperoxidase. |
How long do macrophages circulate for? | 8-12 hours but much longer in tissues. |
What are the roles of monocytes? | Ingest material and present peptides to T cells. To kill mycobacteria and fungi and intracellular organisms e.g. listeria. |
What are the differences between chronic and acute myeloid leukemia? | Pace of disease, presentation, molecular mechanism, method of treatment and outcome. |
What age groups does chronic myeloid leukemia occur? | Occurs in all age groups. |
What are the symptoms of chronic myeloid leukemia? | Anaemia, large spleen and bone pain. |
What proportion of chronic myeloid leukemia cases have an identical cytogenetic and molecular mutation? | 95%. |
What are signs of chronic myeloid leukemia? | Anaemia, high WBC and platelet count. |
What is Imatinib? | Cytotoxic drug that works by inhibiting tyrosine kinase (enzymes that are present in some cancer cells). |
What increases the chances of acute myeloid leukemia? | More common with increasing age. |
When do symptoms of acute myeloid leukemia present? | Presents with symptoms of marrow failure. |
What are some signs of acute myeloid leukemia? | Anaemia, Bleeding (purpura and bruises) and infections (sepsis and pneumonia). |
What is a purpura? | A skin rash resulting from bleeding into the skin from small blood vessels (capillaries). |
Why may chemotherapy not be the best treatment for acute myeloid leukemia? | Diverse cytogenetic changes so no single target for chemotherapy. |
When can chemotherapy be used to treat acute myeloid leukemia? | To produce marrow aplasia. Marrow then regenerates from residual stem cells. |
Define aplasia. | Total or partial failure of development of an organ or tissue. |
How can a transplant be used to treat acute myeloid leukemia? | Peripheral blood or marrow derived stem cells as transplant for selected patients- toxic but effective. |
What are the problems of using chemotherapy to treat acute myeloid leukemia? | Infections (neutropenia), bleeding (thrombocytopenia), psychological (long periods in hospital and uncertainty) and venous access (peripheral/central lines). |