Leukaemia Flashcards
What is leukaemia?
Cancer of haematopoietic cells associated with increased WBC number in bone marrow or blood
4 types of leukaemia
- acute lymphoblastic leukaemia
- acute myeloid leukaemia
- chronic myeloid leukaemia
- chronic lymphocytic leukaemia
How does a haematopoietic stem cell become B and T lymphocytes?
- haematopoietic stem cell
- may become a lymphoid progenitor in the bone marrow
- either becomes a B or T lymphocyte which spill out into peripheral blood
- B lymphocytes will become activated in nearest lymph undergoing germinal centre reaction for specific antigen
- specific B lymphocyte will become a plasma cell
- T cells do cytotoxic cell killing
How does a haematopoietic stem cell become other blood cells?
- HSC becomes a myeloid progenitor cell which will grow and diff. in bone marrow
- these can become mature neutrophils, eosinophils, basophils, monocytes, platelets and red cells leaving marrow and into blood
How do the different types of haematological malignancies arise?
- lymphoid progenitor mutation = ALL (stuck at this stage making lots of these progenitor cells/blasts)
- myeloid progenitor mutation = AML (stuck at this stage again)
- mutation when mature B lymphocyte = CLL
- mutation when lymphocyte in lymph node undergoing germinal centre reaction = lymphoma
- mutation of plasma cells = myeloma
- mutation of matured myeloid progenitors = myeloproliferative disorders
Diagnostic tools for haematological malignancies?
- blood film
- bone marrow biopsy
- flow cytometry
- chromosome abnormalities (G banding and FISH)
- gene point mutations via sequencing
What is flow cytometry?
- immunophenotyping
- looking at antigens on surface of cell
- sometimes cannot see the difference in types of blood cells from microscope morphology so need to see these markers to differentiate
- distinguish cancerous from normal tissue as well as different types of haematological malignancies
- through using antibodies to bind to specific antigens you are searching for
How does G banding work?
- culture cells and stop at metaphase
- colour them and lay them out
- detect chromosomal abnormalities which are present in some haematological malignancies
How does FISH work?
- cells do not need to be in metaphase
- fluorescent probes detect specific DNA sequences/chromosomal translocations/gains/losses of regions in the genome
How is sequencing different from FISH?
- looking at specific DNA sequence changes not larger chromosomal changes
AML and ALL characteristics
- diagnosis
- treatment
- accumulation of undifferentiated blasts in bone marrow
- overwhelm normal blood cells spilling over into peripheral blood
- > 20% blasts in bone marrow or blood to diagnose it
- aggressive/fast growing/ fatal if untreated
- need intensive, high dose, myelosuppressive chemotherapy
- exclude other causes = infections and other malignancies
AML presentation
- low Hb anaemia = tiredness, SOB
- WCC low/neutropenia = fever, pneumonia, fungal infection
- leucostasis = high white cell count so blood is viscous clogging flow in vessels due to overspill = stroke/confusion/SOB/headache
- gum and skin infiltration
- bone pain
- low platelets/thrombocytopenia = bleeding and bruising in GI and cerebral areas
Who is AML common in?
- increasingly frequent in older people
Diagnosis of AML
FBC = low Hb. WCC high or low, low platelets
- renal function (failure?)
- raised urate and LDH
- clotting (APML)
- blood film
- bone marrow biopsy
- immunophenotyping
- cytogenetics
- mutations
Bone marrow biopsy sign of AML
Auer rods
- elongated structures from grouping of granules
AML treatment
- blood transfusion for anaemia
- pit transfusion for thrombocytopenia
- neutropenia = prophylactic antibiotics and neutropenic sepsis treatment immediately with broad spectrum ABs
- look out for tumour lysis=allopurinal/rasburicase fluids
- emergency venesection or leucopharesis for leucostasis
- intensive chemo
- allogeneic stem cell transplant