Vitamin D and Sjögren syndrome.

The immunomodulatory effects of vitamin D have been extensively studied in the context of autoimmunity. Multiple studies have demonstrated a high prevalence of vitamin D deficiency in autoimmune diseases. Recently, a possible protective role of vitamin D in autoimmunity has been described; however, this function remains controversial. Few studies have investigated the role of vitamin D in patients with Sjögren syndrome (SS). In this review, we compiled the main features of SS pathogenesis, the vitamin D immunomodulatory effects and the possible interaction between both. Data suggests that vitamin D may play a role in the SS pathogenesis. In addition, vitamin D low levels have been found in SS patients, which are associated with extra-glandular manifestations, such as lymphoma or neuropathy, suggesting a possible benefit effect of vitamin D in SS.