MBTPS1 and systemic sclerosis: Due to the crucial role of S1P-signaling in homeostasis of the immune system and the endothelium, specific S1PR-modulators are already used in autoimmune disease such as multiple sclerosis and inflammatory bowel disease and constitute a promising therapeutic option for rheumatoid arthritis, systemic lupus erythematosus or systemic sclerosis (SSc) (24–26).