Systemic Cytokine Patterns and Histologic Disease Spectrum in Inflammatory Bowel Disease

Histologic mucosal healing is an increasingly recognized therapeutic target in inflammatory bowel disease (IBD), yet reliable non-invasive correlates remain limited. This study aimed to evaluate circulating cytokine patterns as detectability-based immune signals across the spectrum of histologic disease activity.

In this prospective cross-sectional study, 59 patients with IBD and 36 healthy controls were enrolled. Serum interleukin-10 (IL-10) and interleukin-23 (IL-23) were quantified by ELISA. Histologic activity was graded using the Geboes score. Associations were assessed using non-parametric methods and multivariable logistic regression with Firth penalization.

IL-10 demonstrated apparent separation across histologic states, primarily driven by reduced detectability in active inflammation, and was inversely associated with histologic severity. IL-10 remained associated with histologic status, although estimates should be interpreted cautiously. Detectable IL-23 was confined to moderate-to-severe inflammation and did not show graded discrimination, with interpretation limited by the small number of detectable observations.

IL-10 and IL-23 exhibit complementary patterns, reflecting detectability-based regulatory signaling and a severity-dependent inflammatory threshold, respectively, without evidence of independent clinical utility for IL-23 in the present dataset. These findings are exploratory and require validation in larger prospective cohorts.