Circulating IL-23 Levels and Correlation with SLE Disease Activity: A Meta-Analysis

Objective This study aimed to evaluate the relationship between circulating interleukin-23 (IL-23) levels and systemic lupus erythematosus (SLE) as well as the correlation between plasma/serum IL-23 levels and SLE activity. Methods The MEDLINE, EMBASE, and Web of Science databases were searched for relevant publications up to February 2025. We performed a meta-analysis comparing plasma/serum IL-23 levels between patients with SLE and healthy controls and examined correlation coefficients between circulating IL-23 levels and SLE disease activity. Results Sixteen studies comprising 1,125 patients with systemic lupus erythematosus (SLE) and 774 healthy controls were included. Circulating IL-23 levels were significantly elevated in the SLE group compared with controls (standardised mean difference [SMD]=1.225, 95% confidence interval [CI]=10.803-1.647, p<0.001). Subgroup analyses confirmed consistent findings across ethnic groups (European, Asian, and Arab populations), and the results remained significant irrespective of study size, with both large-sample (n>70) and small-sample (n<70) studies demonstrating higher IL-23 levels in SLE. Stratification by publication year showed that this association persisted in both recent (after 2017) and older (before 2017) publications, indicating temporal stability of the findings. Disease activity analysis revealed significantly higher IL-23 levels in patients with active disease (SLEDAI≥6) compared with those with inactive SLE (SLEDAI<6) (SMD=0.928, 95% CI=0.351-1.505, p<0.001). A pooled analysis of correlation coefficients indicated a trend toward a positive association between circulating IL-23 levels and SLEDAI scores, although this did not reach statistical significance. However, a significant positive correlation was identified between IL-23 levels and anti-dsDNA (correlation coefficient=0.388, 95% CI=0.189-0.556, p<0.001). Conclusions Elevated circulating IL-23 levels were significantly associated with SLE and with disease activity. These findings enhance our understanding of SLE pathogenesis and suggest that IL-23 could serve as a biomarker for monitoring disease activity in SLE.