Soluble interleukin-2 receptor in juvenile rheumatoid arthritis

Juvenile rheumatoid arthritis (JRA) is a chronic, relapsing, inflammatory childhood disease characterized by arthritis and systemic inflammation. At present there is no rapid, efficient laboratory method of assessing disease activity and degree of immune activation. We measured serum soluble interleukin 2 receptor (sIL-2R) levels in 85 samples from 72 patients (22 samples from patients with systemic JRA, 34 from polyarticular patients, 29 from pauciarticular patients, of which 10 were HLA-B27 positive). The mean sIL-2R level from patients was 1565 U/ml, which is significantly elevated compared to control values of 594 U/ml (p less than or equal to 0.005). The highest levels were seen in patients with systemic JRA (mean value 2121 U/ml) while the lowest values were seen in HLA-B27 positive (+) patients (mean value 899 U/ml). Patients with clinically active disease had significantly elevated levels (mean value 1745 U/ml) compared to patients with inactive disease (mean value 846 U/ml, p less than or equal to 0.01). Highest levels were seen in patients with active systemic JRA (mean value 2419 U/ml) while patients with pauciarticular JRA and B27 + JRA had the lowest sIL-2R levels (1167 and 1045 U/ml, respectively). sIL-2R levels were elevated in all subgroups of clinically active patients compared to controls (p less than or equal to 0.0005). Three of the 4 patients with serial sIL-2R measurements showed falling values during the period of clinical remission. Using regression analysis and likelihood ratio tests, we found a significant correlation between sIL-2R levels and both disease activity and joint count (p less than or equal to 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)