The relationship of serum and tissue cathelicidin with the disease in the patients with celiac disease

Introduction: Celiac disease (CD) is an immune-mediated enteropathy triggered in genetically susceptible individuals by gluten-containing cereals. Studies show CD to be a common disorder, and affecting approximately 1% of the population. In recent years, the search for biochemical markers that can be used in the diagnosis and follow-up of CD has been the subject of many studies. Antimicrobial peptides (AMPs) are effector molecules of the innate immune system. AMPs comprise two major subfamilies including defensins and cathelicidins. The only known member of human cathelicidins is cathelicidin LL-37. Cathelicidins act as a primary defense against bacteria and other pathogens in the case of inflammation and play a role in angiogenesis, wound healing, and the regulation of apoptosis. Cathelicidin also has a proinflammatory property and is involved in the development of autoimmune diseases. In our study, we aimed to investigate the relationship of serum and tissue cathelicidin levels with disease in celiac patients. Material and Method: Our study included 41 celiac patients and 22 non-celiac control groups aged 18-65 years. The group with celiac disease was divided into active and remission groups according to the disease status, and a total of three groups were obtained. Patients with heart failure, malignancy, history of acute infection, chronic liver disease, pregnancy, history of acute coronary syndrome in the last 6 months, end-stage renal disease and hyperthyroidism were not included in the study. Serum concentration of cathelicidin was measured using enzyme-linked immunosorbent assay (ELISA) kits. Cathelicidin expression was investigated in the intestinal mucosa of the participants. Results: Serum cathelicidin level was found to be statistically significantly higher in the group with celiac disease [58,68ng/mL (6,9-388,1 ng/mL)] compared to the control group [25,64 ng/mL (0-84,2 ng/mL)] (p₌0,001). When the evaluation was made as 3 groups as celiac active, celiac remission and control, a statistically significant difference was found between cathelicidin levels (p₌0.004). It was found to be statistically significantly higher in the celiac active group than in the control group (p₌0.002) and in the celiac remission group compared to the control group (p₌0.013). When the celiac group was analyzed in terms of active and remission, no statistically significant difference was found (p₌0.540). In the group with celiac disease, a positive correlation was found between serum cathelicidin level and leukocyte, neutrophil, LDH, and triglyceride. Tissue cathelicidin expression was statistically significantly increased in the celiac disease group compared to the control group (p=0.0001). A positive correlation was found between tissue cathelicidin expression and serum cathelicidin level and modified Marsh scoring (p=0.034, p=0.0001, respectively). Results: In our study, cathelicidin expression is increased both in serum and tissue level in celiac disease. In the process triggered by the release of high amounts of cytokines in celiac disease, the host defense peptide cathelicidin may have increased due to its proinflammatory feature. This suggests that the increase in serum and tissue cathelicidin may be a potential biomarker for celiac disease, independent of the clinical activity of the disease.