Cathelicidin - A Novel Potential Marker of Pediatric Inflammatory Bowel Disease

Introduction: Cathelicidin is a multifunctional host defense peptide which may also exert proinflammatory signals and contribute to the development of autoimmune disorders. We aimed to assess serum concentration of cathelicidin in children with inflammatory bowel disease (IBD) compared to healthy controls and to evaluate its relationship with disease activity and phenotype. Patients and Methods: The study group included 68 children with IBD. The control group comprised 20 children with functional abdominal pain. All patients and controls were tested for complete blood count, C-reactive protein, erythrocyte sedimentation rate and cathelicidin. Stool samples were collected to assess calprotectin. Results: Cathelicidin was significantly increased in patients with ulcerative colitis (1073.39 +/- 214.52 ng/mL) and Crohn's disease (1057.63 +/- 176.03 ng/mL) patients compared to controls (890.56 +/- 129.37 ng/mL) (H=16.28; p=0.0003). Cathelicidin was significantly elevated in children with active IBD (1044.90 +/- 176.17 ng/mL) and IBD remission (1098.10 +/- 227.87 ng/mL) compared to controls (Z=3.21; p=0.001; Z=-4.12; p<0.0001, respectively). Negative correlation between cathelicidin and calprotectin in children with ulcerative colitis was found (R=-0.39; p=0.02). Cathelicidin exhibited AUC of 0.815 for differentiation children with ulcerative colitis from the control group. Conclusion: Serum cathelicidin is increased in children with Crohn's disease and ulcerative colitis regardless of clinical activity of the disease suggesting that it may be a potential biomarker of IBD. Inverse correlation between cathelicidin and fecal calprotectin may imply a disparate role of these molecules in the pathophysiology of pediatric ulcerative colitis.