It is generally accepted that sarcoidosis initially arises from the interaction between macrophages, Type 1 CD4+ T Helper (TH1) cells and antigens of unknown origin that drive the production of inflammatory cytokines such as Tumor Necrosis Factor (TNF)-α, Interleukin (IL)-12, IL-2 and Interferon (IFN)-γ which ultimately results in granuloma formation. The gene discussed is IL2; the disease is sarcoidosis.