Circulating interleukin-23 levels in ankylosing spondylitis and their correlation with disease activity :...

To systematically investigate the relationship between circulating interleukin-23 (IL‑23) levels and ankylosing spondylitis (AS) and establish a correlation between these hematological indices and AS activity/severity.

We searched the Medline, Embase, and Cochrane databases; performed a meta-analysis comparing serum/plasma IL‑23 levels in patients with AS to those of controls; and examined the correlation coefficients between serum/plasma IL‑23 levels and AS activity.

Ten studies including 1724 patients with AS and 1589 controls were included in this meta-analysis. This meta-analysis showed that circulating IL‑23 levels were significantly higher in the AS than in the control group (standardized mean difference [SMD] 1.479; 95% confidence interval [CI] 0.308-2.650; p = 0.013). Stratification by ethnicity showed a significantly increased IL‑23 level in the AS group in an Asian population (SMD 1.551; 95% CI 0.543-2.558; p = 0.003). Stratification by adjustment for age and sex revealed significantly higher IL‑23 levels in the AS adjustment group. Subgroup analysis of sample size showed a significantly higher IL‑23 level for a small (n < 150) sample number in the AS group. Meta-analysis of correlation coefficients revealed that the IL‑23 level was positively associated with the Bath Ankylosing Spondylitis Metrology Index (BASMI; correlation coefficient 0.464; 95% CI 0.027-0.752; p = 0.038), erythrocyte sedimentation rate (ESR; correlation coefficient 0.258; 95% CI 0.076-0.422; p = 0.006), and C‑reactive protein (CRP; correlation coefficient 0.291; 95% CI 0.053-0.498; p = 0.017).

This meta-analysis demonstrated that the circulating IL‑23 level is significantly higher in patients with AS, and a significant positive correlation exists between the circulating IL‑23 level and BASMI, ESR, and CRP.