[Cytokine levels in serum of patients with juvenile idiopathic arthritis depending on subtype and disease activity].

We investigated serum levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFalpha) in 25 patients with juvenile idiopathic arthritis (JIA) during both: active and inactive phases of the disease. The polyarticular JIA patients had the highest IL-6 level during both active and inactive periods, TNFalpha level was the highest in the systemic JIA, active and inactive periods. IL-6 and TNFalpha levels were significantly lower than those of controls (p<0.0003) in oligoarticular JIA. IL-6 correlated significantly with C-related protein (CRP) in active period (p<0.001) and inactive period (p<0.05) in oligoarticular JIA patients, such correlation was not found for TNFalpha. In conclusion, IL-6 and CRP may play an important role in JIA and may be used as a marker of disease activity.