Granulomatous inflammation is characterized primarily by accumulation of macrophages
and activated T-lymphocytes, with increased production of key inflammatory mediators, TNF, IFN-γ, IL-2, IL-8, IL-10, IL-12, IL-18, IL-23 and TGF-β, indicative of a Th1-mediated immune response.
The differing incidence across the world may be at least partially attributable to the lack of screening programs in certain regions of the world and
the overshadowing presence of other Granulomatous diseases, such as tuberculosis, that
may interfere with the diagnosis of sarcoidosis where they are prevalent.