OBJECTIVETo investigate the serum levels of Th1/Th2 cytokines in children with non-systemic juvenile onset idiopathic arthritis (non-SOJIA).

METHODSClinical data of 41 children with non-SOJIA, including 11 cases of polyarthritis, 10 cases of oligoarthritis and 20 cases of enthesitis related JIA (ERA), admitted in Children's Hospital of Zhejiang University School of Medicine during November 2012 and May 2015 were retrospectively analyzed. Serum levels of Th1/Th2 cytokines including IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ were measured by flow cytometry in patients with non-SOJIA, and compared with those in patients with SOJIA (SOJIA group, n=85) and healthy children (control group, n=202); their correlations with erythrocyte sedimentation rate and C reactive protein and CRP were analyzed.

RESULTSCompared with the healthy control group, serum levels of IL-2, IL-6 and IFN-γ were significantly increased in patients with non-SOJIA (2.9 vs. 2.6 pg/mL, 9.9 vs. 6.4 pg/mL, 6.3 vs. 5.1 pg/mL, allP<0.05),while levels of TNF-α and IL-10 were significantly decreased (2.7 vs. 3.9 pg/mL, 2.9 vs. 7.1 pg/mL, both P<0.01). Compared with the SOJIA group, serum levels of IL-6 and IL-10 were significantly decreased in patients with non-SOJIA (9.9 vs. 33.5 pg/mL, 2.9 vs. 4.1 pg/mL, both P<0.01), while levels of IL-4 and IL-10 were significantly increased (3.1 vs. 2.3 pg/mL, 6.3 vs. 4.4 pg/mL, both P<0.05). Serum levels of IL-6 in patients with polyarthritis or ERA were higher than that in patients with oligoarthritis (12.7 and 11.0 vs. 4.2 pg/mL, both P<0.05). A positive correlation of IL-6 or TNF-α level with C reactive protein was observed in patients with ERA.

CONCLUSIONSThe results indicate that Th1/Th2 imbalance and Th1 predominance may exist in children with non-SOJIA; and IL-6 may be involved in the pathogenesis of non-SOJIA children with polyarthritis.