The diagnostic role and clinical association of serum proteinase 3 anti-neutrophil cytoplasmic antibodies in Chinese patients with inflammatory bowel disease

Abstract

Background and aim: Accurate differentiation of patients with ulcerative colitis (UC) or Crohn’s disease (CD) is important for appropriate therapy and prognosis. This study was designed to explore the utility of proteinase 3 anti-neutrophil cytoplasmic antibodies (PR3-ANCA) in the diagnosis of Chinese patients with inflammatory bowel disease (IBD).

Methods: Blood samples were collected from 216 Chinese patients, including 175 IBD and 41 colorectal polyps (disease control). Clinical characteristics were extracted from electronic medical records.

Results: Serum PR3-ANCA were increased in UC patients compared to those with CD or colorectal polyps (p < .0001). PR3-ANCA was negative in colorectal polyps and there was no significant difference between CD and colorectal polyps (p > .05). Using the cut-off value of 20 chemiluminescent units (CU) provided by manufacturer, the positive rate of PR3-ANCA was higher in UC than CD (41.7% vs. 1.1%; p < .0001). Receiver operating characteristic (ROC) analysis demonstrated an area under the curve (AUC) of 0.89 (95% CI: 0.84–0.95; p < .0001) for differentiating UC from CD and suggested an optimized cutoff of 7.3 CU which improved sensitivity from 41.7% to 57.1%, while maintaining a specificity of 98.9%. PR3-ANCA in severe UC patients were higher than those with moderate UC (p < .05), no difference was found between those in remission or with mild or moderate activity (p > .05).

Conclusions: Serum PR3-ANCA is a potentially useful clinical biomarker in Chinese patients with IBD. A modified cut-off value of 7.3 CU improves the performance for distinguishing UC from CD.

Keywords:

• Inflammatory bowel disease
• ulcerative colitis
• Crohn’s disease
• PR3-ANCA
• diagnostic

Acknowledgments

This study was performed at Wuhan University. We thank INOVA Diagnostics lnc for providing reagents and Werfen China for providing the Bio-flash instrument.

Author contributions

Y. X. participated in study design, data collection, literature search, data analysis, data interpretation,drafting the article. F.X. was responsible for analysis and interpretation of data, drafting part of manuscript. M.L., W.L., Y.Z., D.S. participated in data collection, literature search and data analysis. Q.Z., N.G.L. and L.L. conceived the study and critically revised the manuscript. All authors commented on drafts of the paper. All authors have read and approved the final version of the manuscript.

Disclosure statement

Gary L. Norman is an employee of Inova Diagnostics. The other authors report no conflicts of interest.

Additional information

Funding

This study was supported by Zhongnan Hospital of Wuhan University Science, Technology and Innovation Seed Fund (grant number cxpy2017033). The funding bodies had no role in the study design, the collection, analysis of data, interpretation of result or the writing of the article and the decision to submit it for publication.