Two days after major surgery, a patient develops fever and malaise. Serum CRP is markedly elevated and the erythrocyte sedimentation rate is raised. Which cytokine, released primarily by activated macrophages, drives hepatic synthesis of CRP and fibrinogen in this acute phase response?
- A IL-6 ✓
- B TNF
- C IL-1
- D IL-12
Correct answer: A. IL-6
Explanation
IL-6 is the principal driver of the hepatic acute phase response, inducing synthesis of CRP, serum amyloid C, and fibrinogen. TNF and IL-1 mediate fever, endothelial activation, and systemic symptoms, but they are not the main stimulus for hepatocyte production of these proteins. IL-12 promotes Th1 differentiation and IFN-gamma production and plays no central role in hepatic acute phase protein induction. Elevated fibrinogen also accounts mechanistically for the raised ESR.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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