Which of the following is important cytokine for granuloma formation
[A] TGF-Beta
[B] TNF-alpha
[C] IFN-Gamma
[D] IL-17
Answer = [C] IFN-Gamma > TNF-Alpha (Ref: Robbins & Cotran Pathologic Basis of Disease 9th Edition)
Immune granulomas are caused by persistent induction of type IV hypersensitivity reactions. Here, macrophages activate T cells to produce cytokines, such as IL-2, which activates other T cells, perpetuating the response, and IFN- Gamma, which activates the macrophages.
So IFN gamma is primary cytokine which drive macrophase towards type IV hypersensitivity abd granuloma formation.
Epithelioid cells (activated macrophages) and mononuclear cells consisting of CD4 helper T cells (Th1 type). Giant cells are formed by fusion of epithelioid cells which are in turn derivd from activated macrophases.
TNF-a is also important in the formation and maintenance of TB and systemic fungal granulomas. TNF-a and interferon-y recruit cells for granuloma formation