Paediatric rheumatology Soluble tumour necrosis factor receptor levels reflect coagulation abnormalities in systemic juvenile chronic arthritis

The objective was to evaluate tumour necrosis factor (TNF) status in patients with systemic juvenile chronic arthritis (s-JCA). Plasma levels of TNF-α, and serum levels of soluble TNF receptor 1 and 2 (sTNFR1 and sTNFR2) were measured using specific immunoassays in 20 patients with s-JCA, 10 with polyarticular JCA and 15 with pauciarticular JCA, and in 20 controls comparable for age. In patients with active s-JCA, circulating levels of TNF-α, sTNFR1 and sTNFR2 were significantly (P <0.001) higher than those of controls. The levels of sTNFR1 and sTNFR2, but not those of TNF-α, were associated with the persistence and severity of systemic symptoms and were significantly correlated with prolongation of partial thromboplastin time and decrease in prothrombin activity. In two patients evaluated during a s-JCA-associated macrophage activation syndrome, a marked increase in sTNFR1 and sTNFR2 was found. Our results suggest that in s-JCA, TNF is involved in systemic manifestations, in the subclinical coagulation abnormalities, and in the development of the macrophage activation syndrome.