DEF4A/hBD2, a non-invasive serum biomarker for detection of Ulcerative colitis

The ulcerative colitis (UC) is a chronic episodic relapsing, and remitting inflammatory bowel disease with increasing frequency worldwide. Along with colonoscopy, faecal calprotectin (FCP) > 150µg/g, elevated faecal Lactoferrin or elevated CRP are now considered for diagnosis and to take treatment decision. But there are a group of patients showing either symptomatic remission with high biomarkers or active disease having no biomarker. Hence, identification of biomarker with better diagnostic potential is still required for UC patients. To determine the deregulated genes in UC, microarray analysis was employed with colonic tissue of UC and irritable bowel syndrome as control. Pathway enrichment analysis with differentially expressed (DE) genes revealed anti-microbial peptide mediated immune response might play pivotal role in UC. Subsequently, qRT-PCR validation depicted that among the DE genes, Defensins showed highest significant alterations in UC compared to control. Among defensins, DEFB4A, DEFA5, and DEFA6, only DEFB4A/hBD2 showed significant upregulation in the UC patients by qRT-PCR. The data was also validated by Immunohistochemistry, and ELISA. A significantly high level of DEFB4A/hBD2 was noted in the serum of active UC patients (p < 0.001) which disappeared in patients in remission (p < 0.001). ROC analysis showed that DEFB4A/hBD2 with AUROC of 0.94 having cut-off value more than 209pg/ml could differentiate between normal and active UC patient with 89% sensitivity, and 80% specificity and with 95% confidence interval of (0.79–0.98). The positive predictive efficiency was 92% while negative predictive efficiency was 73%. These findings highlight that DEFB4A/hBD2 may be considered as a potential serum diagnostic marker for UC patients, though further validation is necessary in larger number of samples.