Studies have shown that JAK-STAT signalling is constitutively activated in sarcoidosis [10, 24–26], In sarcoidosis, dysregulated signalling of cytokines, such as IFN-γ and IL-6, which help to develop granuloma formation, occurs via the JAK-STAT pathway (Fig. 3) [10]. This evidence concerns the gene IFNG and sarcoidosis.