CCL20 and ulcerative colitis: However, in patients with ulcerative colitis, there were no remarkable absolute differences in systemic CCL20 levels between patients with or without VD deficiency, and no direct correlations were found between 1,25(OH)2 concentrations or the 1,25(OH)2/25-hydroxyvitamin D activation ratios and serum CCL20 levels (data not shown).