Value of quantitative detection of plasma cell-free DNA in the assessment of inflammatory bowel disease activity

Abstract

Objective To explore the value of plasma cell-free DNA (cfDNA) in the assessment of inflammatory bowel disease (IBD) activity. Methods From July 2014 to June 2017, 145 IBD patients from the First Affiliated Hospital of Fujian Medical University were selected. The plasma content of cfDNA was detected by picogreen-based fluorescent quantitative method. At the same period, 37 healthy individuals were enrolled as control group. The correlation between cfDNA content and C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and IBD activity was analyzed. The diagnostic capability of cfDNA in IBD activity was assessed by the receiver operating characteristic (ROC) curve. T-test was performed for comparison between two independent samples, and Pearson correlation coefficient test was used for correlation analysis between two variants. Results The content of plasma cfDNA of patients with Crohn′s disease (CD) and patients with ulcerative colitis (UC) were (29.17±2.07) μg/L and (26.86±1.97) μg/L, respectively; which were both higher than those of healthy control group (21.10±1.02) μg/L, and the differences were statistically significant (t=2.609 and 2.082, both P<0.05). Moreover, the content of cfDNA of patients with active CD or UC were (35.72±3.26) μg/L and (32.37±3.42) μg/L, respectively, which were both higher than those of patients with CD or UC in remission ((21.12±1.43) μg/L and (20.82±1.02) μg/L), and the differences were statistically significant (t=3.806 and 3.116, both P<0.01). The cfDNA content of CD patients was positively correlated with CRP, ESR and disease activity (r=0.555, 0.393 and 0.400, all P<0.01). The cfDNA content of UC patients was also positively correlated with CRP, ESR and disease activity (r=0.640, 0.421 and 0.360, all P<0.01). The diagnostic capability of the combination of CRP and ESR was the highest in CD diagnosis, with the area under curve (AUC) value being 0.841, and the sensitivity and specificity being 81.4% and 74.3%, respectively. The diagnostic capability of the combination of cfDNA, CRP and ESR was the highest in UC diagnosis, with the AUC value being 0.851, and the sensitivity and specificity being 74.3% and 96.9%, respectively. Conclusions Increased cfDNA levels in IBD patients are correlated with IBD activity. Detection of cfDNA is helpful in the identification of active IBD, and the combination of ESR and CRP can improve the diagnostic efficiency of UC. Key words: Inflammatory bowel diseases; Crohn disease; Colitis, ulcerative; Cell-free DNA; Disease activity