Antinuclear antibodies seroconversion and endoscopic response to infliximab in biologic-naive Crohn’s disease: a Chinese single-center, retrospective study

Abstract

The development of antinuclear antibodies (ANAs) during infliximab treatment has been observed in previous clinical trials. To evaluate the clinical significance of ANA seroconversion and its potential association with the formation of antibodies against infliximab. Methods: This retrospective study included 130 Crohn’s disease patients undergoing infliximab therapy. ANA titers were measured at baseline and after 6 months of treatment. Inverse probability of treatment weighting was applied to control for confounding variables. Results: Among the 111 patients with negative baseline ANA, 36 (32.4%) developed ANA positivity after 6 months of infliximab treatment. After adjustment with inverse probability of treatment weighting, a significantly higher proportion of patients in the ANA non-seroconversion group achieved endoscopic remission at 6 months compared to those with ANA seroconversion (64.5% vs. 35.5%: adjusted odds ratio [aOR], 3.61; 95% confidence interval [CI], 1.30–10.02; P= 0.014). At 18 months, patients in the non-seroconversion group also exhibited higher rates of both endoscopic response (57.5% vs. 42.3%: aOR, 3.38; 95% CI, 1.15–9.96; P= 0.027) and endoscopic remission (60.0% vs. 40.1%: aOR, 2.91; 95% CI, 1.06–8.01; P= 0.039) compared to the seroconversion group. Additionally, patients who developed ANA seroconversion had a higher rate of detectable antibodies against infliximab at both 6 and 18 months. A multivariable analysis identified female sex, older age at diagnosis, and lower serum albumin levels as independent predictors of ANA seroconversion at 6 months. Conclusions: ANA non-seroconversion at 6 months was associated with higher rates of endoscopic remission and a lower likelihood of developing antibodies against infliximab. (Intest Res 2026;24:376-383)