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.
Dr Maggie Ham and colleagues investigated vitamin D pathways in patients with Crohn's disease according to measures of inflammation and immune response.
Prospectively collected samples of a well-characterized cohort of patients with Crohn's disease 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.
The researchers found that patients with active Crohn's disease had lower serum vitamin D levels than those in clinical remission.
|Gene expression of the vitamin D receptor was higher in peripheral blood T cells from patients with active disease |
|Inflammatory Bowel Diseases|
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.
The team noted that 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 Crohn's disease increased in the presence of vitamin D.
The researchers found that after treatment with infliximab, there were significant increases in serum vitamin D levels in patients.
Dr Ham's team concludes, "Low vitamin D levels are associated with disease activity in Crohn's disease, and increase after infliximab treatment."