Blood and body defences Flashcards
What is a myeloproliferative neoplasms?
Abnormal overproduction of the myeloproliferative cells
What are the signs of polycythaemia?
Itching, flushed skin, splenogamaly, dizziness, headache
What is primary polycythaemia and the cause?
Primary polycythaemia is generally a congenital/genetic condition.
What are the types of primary polycythaemias?
It can be caused by a congenital defect where the cells which respond to EPO have a defect in the gene coding for the EPO receptor. Polycythaemia vera is a congenital condition where there is a JAK2V617F mutation.
What is secondary polycythaemia?
Acquired polycythaemia as a result of other conditions.
What are the types of secondary polycythaemias?
Hypoxia induced- related to COPD, CHF or kidney transplant
Carcinoma of the liver (which is the site of EPO production) and liver (which is the site of HIF-alpha production that drives EPO levels)
Neonatal- transfusion with maternal blood
What is relative polycythaemia?
Reduction of plasma volume caused by vomiting or diarrhoea leads to greater volume of RBCs
What is thrombocythaemia?
Excess platelets caused by mutation in the AK2V617F. Generally asymptomatic but extreme symptoms are haemorrhage, thrombosis and progression into myelofibrosis or leukemia.
What is idiopathic myelofibrosis?
Abnormal platelets, bone marrow fibrosis, splenogamaly caused by JAK2V617F mutation
What is the similary between thrombocythemia and idiopathic myelofibrosis?
Both caused by the JAK2V617F mutation.
What is myelofibrosis?
Scar tissue forming in the bone marrow which impairs the myeloid progenitor proliferation.
What is JAK2?
A non-receptor protein kinase found on the EPO receptor which acts as a signal transductor for the transcription of the JAK-2 protein to control RBC proliferation.
What is V617F?
An autoinhibitory domain encoded in JAK-2 that regulates downstream signalling following EPO/TPO binding to initiate RBC/platelet proliferation.
What increases risk of developing Polycythaemia with V617F Jak 2 mutation?
Sex and V617F mutation homozygous inheritance
What increases risk of developing Thrombocythaemia with V617F Jak 2 mutation?
Depleted iron stores, EPO levels and genetic modifiers
What is hypersensitvity?
Overexcessive immune response to an antigen or allergen.
What is type 1 hypersensitivity?
IgE antibody driven- binds to soluble antigen and via its Fc receptor to activate mast cells and cause degranulation.
What is type 2 hypersensitvity?
IgG/ IgM antibody binds to a cell-associated antigen or cell surface antigen and via its Fc receptor activates the complement system or Natural killer cells to induce destruction. This drives drug allergy