Sunday, 19 October 2014

Cytokines

Cytokines are hormone like molecules that play a role in BOTH innate and adaptive immune responses(Recent Exam Question)
The action of cytokines may be;
1)autocrine-when target cell is the same cell that secretes the cytokine
2)paracrine-when target cell is nearby
3)endocrine-when cytokine is secreted into the circulation and acts at a distal source
The MAIN action is Paracrine
Cytokines have three major structural families;
1)Hematopoetin family-TNF,IL-1,PDGF
2)Transforming Growth Factor family
3)Chemokine family
IL-8 is the ONLY Chemokine that early on was named an Interleukin
Harrison states apart from TH1 and TH2 cells,there is a third type of T helper cell,called TH17 cell,that contributes to host defence against extracellular bacteria and fungi,particularly at mucosal sites(possible AIIMS mcq)
IL-1 is produced by macrophages(AIIMS previous question)
Most potent eosinophil activating cytokine known is IL-5(Robbins)
IL-6 is overproduced in Castleman's disease and is also an autocrine growth factor in Multiple Myeloma(previous question)
IL-11 is used to reduce chemotherapy induced thrombocytopenia in patients with cancer.
IL-12 may be useful as adjuvant in vaccines
The main cytokine involved in Erythema Nodosum Leprosum(ENL)reaction is TNF(AIIMS previous question)
Remember TNF-beta is implicated in the pathogenesis of Multiple Sclerosis,but TGF-beta is a therapeutic agent used in Multiple sclerosis...Interferon beta is also used as an immunomodulator in Multiple sclerosis
Therapeutic uses of IFN-alpha are;
1)AIDS related Kaposi Sarcoma
2)Malignant Melanoma
3)Chronic Hepatitis B and C infections
Therapeutic use of IFN-gamma-chronic granulomatous disease
IL-18 s a marker of acute Kidney injury

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