How to diagnose and manage difficult problems of calcium metabolism in sarcoidosis: an evidence-based review

Purpose of review Calcium metabolism impairments have long been recognized as a complication of sarcoidosis. For more than six decades physicians and investigators have been trying to elucidate this severe problem; nevertheless it seems puzzlingly new for both readers and researchers. Recent findings This review highlights the problems of calcium metabolism in sarcoidosis in relation to vitamin D synthesis, which is definitely altered by granulomatous inflammation. Increasing evidence suggests that vitamin D is an immunomodulating hormone that inhibits both antigen presentation by cells of the innate immune system, and the cytokine release and proliferation of Th1 cells. As calcium homeostasis is primary controlled by levels of vitamin D, parathyroid hormone (PTH) and calcitonin, this literature review emphasizes the role of general immunomodulating properties of vitamin D and the correlation with calcium metabolism impairments, with the special accent on already known interactions with sarcoidosis. Summary Granuloma formation has been related to a failure of the innate immune system. One of the possible explanations is a vitamin D deficiency. The evidence-based findings on calcium metabolism impairments and the interactions with vitamin D might help both clinicians and researchers in developing new strategies