Vitamin D in autoimmune bullous diseases

Numerous epidemiological studies have suggested a link between vitamin D deficiency and the development of various autoimmune diseases, including diabetes mellitus type 1, rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis or systemic lupus erythematosus. More recently, such a link has been also proposed for autoimmune bullous diseases (AIBD). This is a relatively rare and potentially life-threatening, organspecific group of inflammatory skin diseases characterized by the presence of tissue-bound and circulating autoantibodies against various molecules present in desmosomes (in pemphigus diseases) or hemidesmosomes (in pemphigoid diseases). In addition to the well-known role of vitamin D in calcium and phosphate homeostasis, the hormonally active vitamin D metabolite, 1,25-dihydroxyvitamin D-3 (calcitriol), exerts potent effects on cellular differentiation and regulation of immune responses via binding to the vitamin D receptor present in most cells of the immune system. Since cells of both, the innate and adaptive immune systems, are known to be relevant in AIBD, the role of vitamin D analogues in the treatment of patients with these disorders deserves much attention. This mini-review summarizes recent epidemiological and experimental studies on vitamin D involvement in the autoimmune bullous diseases.