In granulomatous inflammation, the epithelioid cells are derived from which cell type, and the key cytokine maintaining the granuloma is:

• A Neutrophils; IL-8
• B Dendritic cells; IL-4
• C Plasma cells; IL-17
• D Activated macrophages (histiocytes); IFN-gamma (from Th1 cells and NK cells) ✓

Explanation

Epithelioid cells are activated macrophages that have undergone morphological transformation — they acquire abundant pink cytoplasm and elongated nuclei due to stimulation by IFN-gamma produced by Th1 CD4+ lymphocytes. IFN-gamma is the master cytokine driving macrophage activation and granuloma formation; IL-12 from macrophages drives Th1 differentiation in a feed-forward loop. IL-4 drives M2 macrophage activation, not granuloma formation.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.