Granuloma formation requires which macrophage-derived cytokine that drives CD4+ T-helper cell differentiation into IFN-γ–producing Th1 cells to sustain macrophage activation?
- A IL-12 ✓
- B IL-4
- C IL-10
- D IL-13
Correct answer: A. IL-12
Explanation
IL-12 produced by macrophages and dendritic cells is the key cytokine driving naive CD4+ T-cell differentiation into Th1 cells. Th1 cells secrete IFN-γ, which activates macrophages to become epithelioid cells and fuse into giant cells — the cellular hallmarks of granulomatous inflammation. IL-4 and IL-13 drive Th2 differentiation; IL-10 is broadly anti-inflammatory. Defects in the IL-12/IFN-γ axis predispose to disseminated mycobacterial infections.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.