In addition to being important in calcium and phosphorus metabolism, bone formation, and mineralization, vitamin D also plays a part in the maintenance of immune homeostasis. Vitamin D receptors are expressed in a number of different tissues, including, and perhaps most notably, on immune cells. The presence or absence of activated vitamin D has a number of effects on in vitro immune cell function. This review describes the possible immunoregulatory role of vitamin D in rheumatoid arthritis with clinical and animal studies.
From the *Shanxi Medical University, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province, China; †Division of Rheumatology, Department of Medicine, University of Pennsylvania; and ‡VA Medical Center, Philadelphia, PA.
No funding support was received for this study.
The authors have nothing to disclose.
Correspondence: Hongyan Wen, MD, Shanxi Medical University, No. 56 Xinjian Road South, Taiyuan, Shanxi Province 030001, China. E-mail: email@example.com.