In chronic granulomatous inflammation, the multinucleated giant cells form by fusion of macrophages under cytokine stimulation. The cytokine most critical for macrophage activation and granuloma maintenance is:

• A IL-4 (interleukin-4)
• B IL-10 (interleukin-10)
• C IFN-γ (interferon-gamma) ✓
• D TGF-β (transforming growth factor-beta)

Explanation

IFN-γ produced by Th1 CD4+ T cells and NK cells is the principal activator of macrophages in granulomatous inflammation, converting them to 'activated' or 'epithelioid' macrophages with enhanced microbicidal capacity and cytokine production. TNF-α synergizes with IFN-γ to maintain granuloma integrity. IL-4 (from Th2 cells) can also induce giant cell formation but promotes alternative activation (M2). IL-10 is anti-inflammatory; TGF-β promotes fibrosis and Treg differentiation.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.