The demonstration of the quantitative prevalence of specific cytokines in JIA formed the basis for the introduction of biological anticytokine drugs to treatment. Routine assessment of the concentration of these cytokines in blood serum may enable earlier decision making on the legitimacy of biological treatment (anti-TNF). The aim of the study was to assess the diagnostic value of TNFalpha, IL-6, and IL-1beta in monitoring the course of the disease and effectiveness of treatment with etanercept of children with oligo- and polyarticular JIA.
In a 1-year prospective study, cytokine levels were measured using ELISA in serum samples for 19 JIA patients in whom no clinical improvement was noted in spite of treatment with disease modifying antirheumatic drugs (DMARDs) and glucocorticosteroids (GCS). All the patients started treatment with ETN. The control group included healthy children (n = 18).
Concentrations of TNF-a and IL-6 in blood serum at time 0 were significantly higher than in the control group. IL-6 concentration decreased during treatment with ETN in children in the inactive phase of the disease. Mean concentrations of TNF-a in serum increased several dozen times irrespective of clinical improvement. TNFalpha concentrations were statistically significantly higher in patients in the inactive phase of the disease in comparison with those in the active phase and correlated with the dose of ETN. Only the concentration of IL-6 correlated with the JADAS-27 value at all time points.
We conclude that IL-6 may serve as a biomarker of activity of the disease in children with JIA treated with ETN.