As a consequence of these effects, TL1A and its receptor are frequently involved in the pathogenesis of many autoimmune and inflammatory diseases, including rheumatoid arthritis [13, 14], psoriasis [15], and inflammatory bowel diseases [16, 17], most of them characterized by a Th1/Th17 microenvironment as sarcoidosis [17–19]. The gene discussed is TNFSF15; the disease is sarcoidosis.