Anti-OmpC antibodies in Crohn's disease and ulcerative colitis: evidence from a systematic review and meta-analysis

Anti-OmpC antibodies target the Escherichia coli outer membrane porin C. Their diagnostic and prognostic roles in inflammatory bowel disease (IBD) remain uncertain. We systematically assessed their prevalence, diagnostic accuracy, and clinical associations in Crohn's disease (CD) and ulcerative colitis (UC).

We performed a systematic review and meta-analysis (PROSPERO CRD420251066959) of 31 studies including ∼11 000 participants with CD, UC, and controls. Random-effects models estimated pooled prevalence, odds ratios (OR), sensitivity, specificity, diagnostic odds ratios (DOR), and summary receiver operating characteristic curves. Subgroup and sensitivity analyses were performed by assay cutoff, and publication bias was evaluated with funnel plots, Egger's regression, and trim-and-fill.

For CD, 11 studies compared patients with controls; 8 using standardized ELISA cutoffs showed a strong association (OR = 6.99, 95% CI 3.99-12.23; I² = 58%). For UC, 11 studies yielded OR = 4.75 (95% CI 2.82-7.99; I² = 37%). Pooled prevalence was 36.9% in CD and 26.8% in UC. Diagnostic accuracy showed modest sensitivity (CD 0.39; UC 0.30) but high specificity (CD 0.89; UC 0.88), with area under the curve values of 0.76 and 0.77. In CD, OmpC positivity was associated with complicated phenotype (OR = 2.77) and surgery (OR = 2.41), but not with location, activity, or extra-intestinal manifestations.

Anti-OmpC antibodies are strongly associated with CD and show a supportive but less consistent association in UC, with high specificity but limited sensitivity. In CD, OmpC positivity is associated with complicated disease behavior and increased odds of surgery, although these findings should be interpreted cautiously given the observational nature of the included studies. Incorporation into multi-marker serological panels may enhance diagnostic confidence and risk stratification.