The study aimed to compare the accuracy of selected biologic markers in assessing the disease activity in patients with Crohn's disease (CD). The analysis included serum IL-2, IL-6, IL-17, TNF-α, IFN-γ, hsCRP, peripheral CD4 + CD25 + FOXP3 + regulatory T cells, as well as fecal calprotectin and lactoferrin. A group of 55 adults with CD was enrolled to the study. Disease activity was assessed using Crohn's Disease Endoscopic Index of Severity (CDEIS), which currently represents the gold standard for the evaluation of endoscopic activity. For clinical activity scoring, the Crohn's Disease Activity Index (CDAI) was used. Concentrations of investigated markers were estimated by means of flow cytometry and enzyme-linked immunosorbent assays, and the results were correlated with both indices. The study demonstrated that both fecal markers, i.e. calprotectin (r = 0.827, p < 0.001) and lactoferrin (r = 0.704, p < 0.001), correlate closely with CDEIS score, and might be used to evaluate the severity of CD in clinical setting. The correlation of those markers with CDAI was also significant, with r = 0.742 for calprotectin (p < 0.001) and r = 0.675 for lactoferrin (p < 0.05). As for the other investigated markers, only hsCRP (r = 0.672, p < 0.001) and IL-17 (r = 0.296, p < 0.005) correlated closely with CDEIS. The correlation of the markers with CDAI was also significant, though weaker, with r = 0.518 for hsCRP (p < 0.001) and r = 0.296 for IL-17 (p < 0.05). The study showed that IL-17, despite its vague role in the pathogenesis of CD, might be a useful marker, comparable with hsCRP, in assessing the activity of the disease.
Keywords: Biologic markers; CDAI; CDEIS; CRP; IL-17; calprotectin; crohn’s disease; lactoferrin.