CCR6 and inflammatory bowel disease: Given the overexpression of the Th17 cell chemoattractant CCL20 in the intestinal epithelium of patients with IBD and the suggested inhibitory effects of calcitriol on CCR6 + Th17 cells and CCL20 expression, we aimed to investigate the systemic serum CCL20 levels in patients with IBD and correlate them with VD status.