Potential Effects of Interleukins on the Pathogenesis of Systemic Onset Juvenile Idiopathic Arthritis

To analyze the correlation of cytokines with clinical inflammatory indexes in systemic onset juvenile idiopathic arthritis (SOJIA).

A total of 30 active SOJIAs, 30 remission SOJIAs, and 20 normal controls were enrolled. The clinical inflammatory indexes such as tender joints counts, swelling joints counts, C-reactive protein, erythrocyte sedimentation rate, visual analogue scale (VAS), and disease activity score 28 (DAS28) were detected. The serum cytokines interleukin (IL)-17, IL-6, IL-21, interferon (IFN)-γ, and IL-4 levels were determined with enzyme-linked immunosorbent assay method. The correlation coefficients between these cytokines and two clinical indexes (VAS and DAS28) in the active SOJIA group were calculated with the Spearman's method.

The serum IL-17 and IL-6 levels in active SOJIA group were significantly increased compared with those in the remission SOJIA group and control group (p < 0.05), and the serum IL-21, IFN-γ, and IL-4 levels showed no obvious difference. In the active SOJIA group, the Spearman coefficients between IL-17 and DAS28, IL-17 and IL-6, IL-6 and DAS28, and between IL-17 and VAS were 0.686 (p = 0.000), 0.833 (p = 0.000), 0.633 (p = 0.000), and 0.524 (p = 0.003), respectively. There was no correlation between cytokines of IL-21, IFN-γ, and IL-4 and the clinical indexes of DAS28 and VAS. Furthermore, in the other two groups, none of the five cytokines exhibited an association with DAS28 or VAS.

IL-6 and IL-17 were significantly correlated with DAS28 and VAS, and they might be considered as therapeutic targets for the treatment of SOJIA.