Immunology 4b - Immune modulation 2 Flashcards
MOA of corticosteroids
Inhibit phospholipase A2 thus reduce inflammation, effect on phagocytes, effect on lymphocytes
Normal function of phospholipase A2?
This enzyme is involved in the conversion of phospholipids to arachidonic acid which is then converted to leukotrienes and prostaglandins by COX which are pro-inflammatory
Effect of steroids on phagocytes
Decrease traffic of phagocytes in to inflamed tissue, reduce expression of adhesion on the endothelium + block signals that tell immune cells to move from blood in to tissue
Which WCC marker is transiently affected by taking steroids?
Transient rise in neutrophil count
Effect of steroids on lymphocytes
Lymphopenia by sequesteration of lymphocytes in lymphoid tisuse CD4 >CD8 >B cells
Blocks cytokine gene expression
Decreased antibody production
Promotes apoptosis
SEs of corticosteroids (metabolic and others)
Metabolic: cushingoid features
Others: cataracts, glaucoma, peptic ulceration, pancreatitis
Immunosuppression
Examples of anti-proliferative agents
Mycophenolate mofetil, azathioprine, cyclophosphamide
Which antiproliferative agent affects B>T?
Cyclophosphamide
MOA of antiproliferative agents
Inhibit DNA synthesis thus inhibit lymphocyte proliferation.
MOA cyclophosphamide
Alkylating agent (alkylates guanine base of DNA)
Indications for cyclophosphamide
COnnective tissue disease
Vasculitis e.g. SLE, Wegner’s
GvHD
SE of cyclophosphamide
BM suppression
Haemorrhagic cystitis (toxic metabolite secreted in urine)
Malignancy - bladder cancer, non-melanoma skin cancer, haematological
Azathioprine MOA
Purine analogue so blocks purine de no vo synthesis
T>B
Indications of azathioprine
Transplantation
Autoinflammatory disease e.g. IBD
Autoimmune disease
SE of azathioprine
Accumulation if have TPMT deficiency
Hepatotoxicity
Infection
Mycophenolate MOA
Anti-metabolite, blocks de novo guanine synthesis
Indications of mycophenolate
Transplantation (gold standard)
Autoimmune disease and vasculitis
SE of mycophenolate
Infection - HSV reactivation and progressive multifocal leukoencephalopathy (JC virus)