LAUSR

Juvenile idiopathic arthritis (JIA) has three major onset types with widely varying clinical features. We assessed the natural killer T (NKT) cell function in patients with different JIA subtypes, and found systemic patients exhibited lower NKT cell counts, perforin and granzyme B expression, while the pauciarticular and polyarticular patients displayed higher perforin and granzyme B expression as compared with the controls. The synovial fluid had more NKT cells with higher levels of perforin, granzyme B, and tumour necrosis factor (TNF)-α than peripheral cells. The polyarticular patients that responded to etanercept had lower NKT cell counts, intracellular perforin, granzyme B and the mean fluorescence intensity of TNF-α than the patients that did not respond. Treatment with etanercept reduced the granzyme B and perforin, interferon (IFN)-γ and TNF-α expression in NKT cells in the responsive group. Therefore, a higher NKT cell function may indicate a decreased response to etanercept in polyarticular patients.