In addition to its localization within sarcoid granulomas, heightened C. acnes-specific Th1 immune responses, characterized by increased interferon (IFN)-γ and interleukin (IL)-2 production, are observed in the peripheral blood and bronchoalveolar lavage (BAL) cells of patients with sarcoidosis, supporting its potential role as a causative antigen (13–18). Here, IFNG is linked to sarcoidosis.