IDO1 and peeling skin syndrome: Thus, quantitative and functional modifications of IL-10-producing B cells, Tregs and IDO-producing cells, might play a role in the pathogenesis and disease activity of autoimmune systemic disorders, including primary Sjögren's syndrome (pSS) [21], an autoimmune exocrinopathy characterized by chronic lymphocytic inflammation of the lacrimal and salivary glands resulting in keratoconjunctivitis sicca and xerostomia.