Differential Diagnostic Significance Of Anti-GP2 For Inflammatory Bowel Disease:A Meta-analysis

Objective: To investigate the differential diagnostic significance of antizymogen granule membrane glycoprotein 2 antibody(anti-GP2) for inflammatory bowel disease(IBD),IBD subtypes and to assess its predictive value for the disease location in IBD patients.Methods: All articles about anti-GP2 and IBD were systematically searched with Pub Med, EMBASE, Ovid and Web of Science, CNKI and other websites comprehensively. which met the study criteria were included in this Meta-analysis. Data extraction was performed by two independent reviewers. Quality assessment of diagnostic accuracy studies 2(QUADAS2) items were used to evaluate the quality of included studies. Meta-disc 1.4 and Stata12.0 software were used to synthesize data. The Pooled sensitivity, specificity, diagnostic odds ratio, the area under curve(AUC) were used to assess the diagnostic value of anti-GP2.Results: Thirteen studies were included in this meta analysis, involving 1724 patients with CD, 1317 patients with UC, 869 health donors and 88 non-IBD gastrointestinal diseases. For distinguishing IBD from health donors, the pooled sensitivity, specificity, positive and negative likehood ratio, diagnostic odds ratio and AUC of anti-GP2-Ig G were 0.165, 0.962, 4.582, 0.845, 5.526, and 0.4703 respectively, and those of anti-GP2-Ig A/Ig G were 0.167, 0.964, 5.222, 0.843, 6.356, and 0.8430 respectively. For distinguishing IBD from non-IBD gastrointestinal diseases, the pooled sensitivity, specificity, positive and negative likehood ratio and diagnostic odds ratio of anti-GP2-Ig A/Ig G were 0.196, 0.920, 2.322, 0.883 and 2.742.For distinguishing CD from UC, the pooled sensitivity, specificity, positive and negative likehood ratio and AUC of anti-GP2-Ig G were 0.233,0.949, 3.936, 0.800, 5.147, and 0.5628 respectively, and those of anti-GP2-Ig A were 0.139, 0.982, 6.289, 0.887, 7.539, and 0.7788, and of anti-GP2-Ig A/Ig G were 0.236, 0.946, 4.309, 0.805, 5.623, and 0.6944 respectively. Anti-GP2-Ig A /Ig G had a lower sensitivity at 0.301(95%CI 0.262~0.342), higher specificity at 0.902(95%CI 0.836~0.949) and the DORs at 4.017(95%CI 2.083~7.747) for CD patients with small bowel involvement.Conclusion: This is the first meta-analysis to assess the diagnostic accuracy of anti-GP2 detecting IBD. Due to its lower sensitivity, anti-GP2 appears to be a weak screening test for IBD, however, its higher specificity indicates a strong power to distinguish IBD from non-IBD, and CD from UC. Anti-GP2 has certain guiding significance for distinguishing CD location. The patients with small bowel CD had higher Anti-GP2 expression.