ORIGINAL ARTICLE The status of serum vitamin D in patients with active Behcet’s disease compared with controls Alireza KHABBAZI, 1 Nadereh RASHTCHIZADEH, 1 Amir GHORBANIHAGHJO, 2 Mehrzad HAJIALILOO, 1 Mortasa GHOJAZADEH, 1 Ramin TAEI 1 and Sousan KOLAHI 1 1 Tabriz Rheumatology Research Team, Connective Tissue Research Center, Tabriz University of Medical Sciences, and 2 Biochemistry Laboratory, Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Abstract Objective: The aim of this study was to characterize the status of vitamin D in patients with active and recently diagnosed Behcet’s disease (BD) and the relationship between vitamin D levels and BD activity. Methods and materials: In this cross sectional study 48 patients with BD and 47 age- and sex-matched healthy controls were included. BD was diagnosed by the International Criteria for BD. Behcet’s patients were new cases who were not on any treatment. BD activity was measured by the Iranian Behcet’s Disease Dynamic Activity Measure (IBDDAM) and Behcet’s Disease Current Activity Form (BDCAF). 25(OH)D measured by enzyme- linked immunosorbent assay method as an indicator of vitamin D status. Results: The mean 25-hydroxyvitamin D (25(OH)D level in the BD group was lower than the control group. Insufficiency and deficiency of 25(OH)D in the BD group was more common than the control group. No corre- lation was observed between the total IBDDAM, ophthalmic IBDDAM, and BDCAF with 25(OH)D levels. No correlation was found between the major symptoms of BD and 25(OH)D value. Conclusions: Our study suggests that deficiency of 25(OH)D may be a trigger factor for BD. Key words: 25(OH)D, Behcet’s disease, pathogenesis, vitamin D. INTRODUCTION Behcet’s disease (BD) is a chronic, relapsing and inflam- matory multisystem disease characterized by recurrent oral aphthous ulcers, genital ulcers, uveitis and skin lesions. The etiology of BD is unknown but genetic and environmental factors, especially microbial agents are suggested to be important. 1 Recent studies have dis- closed the involvement of excessive Th1 cell functions as well as the innate immune system in the pathogene- sis of BD. 2 Do et al. demonstrated a higher constitutive expression of Toll-like receptor 2 (TLR2) and TLR4 in the blood monocytes derived from BD patients com- pared to that of healthy controls. 3 Vitamin D has been shown to have an important reg- ulatory role in the immune system function. 4–6 It affects many aspects of the innate and adaptive immune sys- tem. Vitamin D decreases the antigen-presenting activity of macrophages to lymphocytes by downregulation of class II major histocompatibility complex and costimu- latory receptor expression. 7 It also inhibits the differen- tiation of monocytes into dendritic cells (DCs) and the T-cell stimulatory activity of DCs. 8–11 Vitamin D decreases the production of interleukin (IL)12 and increases the production of IL10. 8,9 The result is the inhibition of Th1 and Th17 cell development. 12 A growing body of evidence supports the hypothesis that vitamin D is an environmental factor important in the etiology of T-cell mediated autoimmune diseases. 13–16 Correspondence: Dr Sousan Kolahi, Rheumatology Research Team, Internal Medicine Department, Emam Reza Hospital, Tabriz 5166614756, Iran. Email: Susan.kolahi@gmail.com © 2013 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd International Journal of Rheumatic Diseases 2013