IL17A and autoimmune disease: This, together with our experience that circulating IL-17 is very difficult to detect in other autoimmune disorders such as rheumatoid arthritis, we investigated the levels of IL-17 and IL-17 promoting cytokines in a large cohort of SSc patients (n = 177) consisting out of 110 patients with LSSc, 34 with ldSSc and 33 with the edSSc phenotype.