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P084 C-Reactive Protein Correlates with Tumor Necrosis Factor-α in Ulcerative Colitis

McDonagh, P.(1);O'Connell, F.(2);O'Connell, J.(1);Argue, R.(1);Corcoran, R.(1);Kevans, D.(1);O'Sullivan, J.(2);

(1)St James's Hospital, Department of Gastroenterology, Dublin, Ireland;(2)Trinity College Dublin, Trinity Translational Medicine Institute, Dublin, Ireland

Background

Monitoring disease activity in Ulcerative colitis (UC) is essential. Inflammatory markers like C-Reactive Protein (CRP) and faecal calprotectin have been shown to correlate with clinical and endoscopic disease activity. To date the relationship between CRP and the inflammatory analytes within the colonic microenvironment have not been analysed.

Methods

Our primary aim was to evaluate the relationship between CRP and key inflammatory cytokine, TNF-α, in UC patients.  We also sought to investigate whether CRP correlates with clinical parameters.  Ethical approval was granted by our Research Ethics Committee.  Patients over the age of 17 with a confirmed diagnosis of UC presenting for colonoscopy were offered the opportunity to participate.  Basic patient demographics and Mayo score were recorded.  At endoscopy colonic biopsies were taken and cultured in dimethyl sulfoxide (DMSO).   Multiplex inflammatory and angiogenic enzyme-linked immunosorbent assay (ELISAs) were performed to evaluate the colonic microenvironment and assess real time secretion of TNF-α.  Correlations were carried out on SPSS 24 and plotted using R Studio corrplot.

Results

26 patients with UC participated in the study.  The mean Mayo score was 4 (range 0-10).  At endoscopy 15% had severe colitis (Mayo endoscopy sub-score 3), 31% had moderate disease, 54% had mild disease. 35% of patients were receiving biologic therapy.  The mean CRP was 6.19mg/L (range 1-48.35mg/L), albumin 43.5g/L (range 31-49g/L).  CRP had a negative correlation with albumin (r=-0.585, p-value 0.002).  CRP had a statistically significant positive correlation with clinical, endoscopic and total Mayo scores (r= 0.469, 0.543, 0.526. p-values 0.016, 0.004, 0.006, respectively).  Bleeding at colonoscopy also correlated very strongly with an elevated CRP (r=0.859, p-value=0.00).  CRP had a moderate positive correlation with TNF-α (r=0.603, p-value=0.001) and VEGF receptor (r=0.492, p-value=0.011) levels.   

Conclusion

CRP displayed a statistically significant positive correlation with the Mayo score.  There was a significant correlation between the CRP and TNF-α expression within the colonic micro-environment. TNF-α is a key cytokine and therapeutic target in UC, its relationship with CRP has not been previously assessed.  CRP is produced primarily by hepatocytes and is activated by TNF-α, interleukin 6 and interleukin 1β.  It therefore stands to reason that there would be correlation between the two. The importance of TNF-α in UC is well known, this study supports and provides new evidence for the use of CRP as a non-invasive marker of disease activity.

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