SERUM INTERLEUKIN-12 CONCENTRATION IN JUVENILE CHRONIC ARTHRITIS

Objectives-The aim of this study was to evaluate serum interleukin (IL ) 12 concentration in patients with juvenile chronic arthritis (JCA), according to disease subtype, activity, and duration. IL12 has been de monstrated to prime the selective expansion of T helper (Th) cells wit h a Th1-type pattern of cytokine production. Methods-Sixty eight serum samples from 50 JCA patients (12 systemic, 12 polyarticular, 26 pauci articular), 20 serum samples from age matched healthy controls were te sted with two different immunoassays specific for total IL12 (p40 and p70 heterodimer) and for IL12 (p70) heterodimer, respectively. The fol lowing disease activity parameters were evaluated: (a) presence of art hritis at least in one joint, (b) physician global estimate of disease activity, (c) disability index according to the Childhood Health Asse ssment Questionnaire (CHAQ), (d) C reactive protein (CRP). Results-Tot al IL12 (p40 and p70 heterodimer) was significantly higher in JCA acti ve patients than in those on clinical remission and in healthy control s (p < 0.001). Conversely, detectable concentrations of IL12 (p70) het erodimer were found in three active JCA patients only. Moreover, total IL12 (p40 and p70 heterodimer) showed a significant negative correlat ion both with time from disease diagnosis (r = -0.29, p = 0.04) and, f or the pauciarticular subgroup, with disease activity duration (r = -0 .71, p < 0.001). Conclusions-This study shows that the p40 moiety of I L12 is increased in serum samples from active JCA patients, especially in the earliest phases of the disease, whereas biological active IL12 (p70) heterodimer is virtually undetectable.