Abstract

Background
The pathogenesis of juvenile idiopathic arthritis (JIA) is not fully understood. So, this study was conducted to investigate clinical usefulness of serum IL-33 levels as an indicator of disease activity in JIA.

Methods
This cross-sectional study was conducted on 45 JIA patients. All patients were subjected to detailed history taking, full clinical examination with emphasis on pattern and distribution of articular and extra-articular involvement. Juvenile arthritis disease activity score (JADAS28) was assessed. Venous blood (10 ml) was collected to assess routine laboratory investigations in addition to IL-33.

Results
Most of patients had sudden arthritis onset (64.4%) and (95.6%) had progressive course. Most of patients (64.4%) had general sites of distribution. 88.9% had emotional aggravation factor, while 86.7% had medication and movement as relieving factors. Only 8.9% of patients' diseases are controlled, 46.7% had relapse, and 6.7% stopped treatment. 66.7% of patients had good response and 33.3% had poor response. JIA patients had a significantly higher serum IL-33 levels compared to IL-33 serum in the control group (p=0.008).
There were significant positive correlation between IL-33 with duration of disease (p=0.002, r=0.612), DAS28CRP (p < 0.001, r=0.705) and DAS28ESR (p=0.001, r=0.667), However, serum IL- 33 levels did not significantly correlate with the levels of serum CRP or ESR.

Conclusions
JIA patients have significantly elevated IL-33 serum concentrations and that considerably correlated with clinical, laboratory and activity parameters of disease suggesting that it could be a valuable marker of JIA disease activity.