A 45-year-old with sarcoidosis has non-caseating granulomas. The core of the granuloma contains epithelioid macrophages and Langhans giant cells. Which cytokine produced by CD4+ Th1 cells is most critical for maintaining granuloma integrity by preventing macrophage dispersal?

• A IL-4
• B IFN-γ ✓
• C IL-13
• D IL-10

Explanation

Granuloma formation requires IL-12 (from macrophages) to stimulate Th1 CD4+ cell differentiation, which then produces IFN-γ. IFN-γ is the key cytokine that activates macrophages into epithelioid cells and maintains granuloma structure. TNF-α (produced by activated macrophages) is also critical for granuloma maintenance — anti-TNF therapy (infliximab, adalimumab) can cause reactivation of latent TB by disrupting granuloma integrity. IL-4/IL-13 drive Th2 responses (parasitic immunity, allergy); IL-10 is anti-inflammatory and would suppress 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.