Background: Vitamin D deficiency is common in patients with Crohn's disease (CD), although whether this impairs immune responsiveness, and is related to disease activity per se, remains unclear. We sought to investigate vitamin D pathways in patients with CD according to measures of inflammation and immune response.
Methods: Prospectively collected samples of a well-characterized cohort of patients with CD were used to measure serum 25(OH)-vitamin D levels by enzyme-linked immunoassay. Related gene expression was determined by polymerase chain reaction in T cells. The effect of vitamin D on the proliferation of isolated CD4+ cells was determined.
Results: Patients with active CD had lower serum vitamin D levels than those in clinical remission; this measurement was independent of season or reported use of vitamin D supplements. Harvey–Bradshaw Index scores, but not C-reactive protein, correlated with serum vitamin D levels. Gene expression of the vitamin D receptor was higher in peripheral blood T cells from patients with active disease than in those in remission. The proportion of CD25hi CD4+ cells from patients with CD increased in the presence of vitamin D. After treatment with infliximab, significant increases in serum vitamin D levels were noted in patients.
Conclusions: Low vitamin D levels are associated with disease activity in CD and increase after infliximab treatment.
Article first published online 27 March 2014
Division of Gastroenterology, Center for Inflammatory Bowel Disease, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Reprints: Alan C. Moss, MD, Division of Gastroenterology, Center for Inflammatory Bowel Disease, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Boston, MA 02215 (e-mail: email@example.com).
A. C. Moss is supported by NIH Grant K23DK084338.
The authors have no conflicts of interest to disclose.
Received January 08, 2014
Accepted January 29, 2014