Vitamin D, autoimmunity and immune-related adverse events of immune checkpoint inhibitors

In addition to its quintessential role in bone homeostasis, vitamin D also plays an important role in regulating the immune system. As such, many studies have demonstrated the therapeutic benefit of vitamin D in treating autoimmune diseases. This immunomodulatory activity of vitamin D has recently attracted more attention due to the rapid development of immunotherapies for cancers, including melanoma. Patients on cancer immunotherapies can suffer from immune-related adverse events (irAEs), which can involve any organ system and range from common dermatological reactions to extremely severe cases of fatal myocarditis in metastatic melanoma patients. Since there are currently no effective approaches to predict or prevent irAEs, it is attractive to potentially leverage the intriguing immunomodulatory effects of vitamin D within this context. This review will discuss recent research investigating the possibility of using vitamin D to alleviate autoimmunity and irAEs with the hope of improving outcomes for patients on cancer immunotherapies, especially within the context of dermatology.