Serum levels of hyaluronic acid indicate the severity of joint symptoms in patients with systemic and polyarticular juvenile rheumatoid arthritis

Objective. Elevated serum levels of hyaluronic acid (HA) correlate with joint inflammation in adult rheumatoid arthritis (RA). There are no laboratory indices for specifically assessing joint inflammation. Therefore, serial measurements of HA were assessed as a possible tool for measuring the severity of arthritic symptoms in children with juvenile rheumatoid arthritis (JRA). Methods. Serum levels of HA, measured by a sandwich assay method using HA binding protein, were correlated with the severity of joint symptoms and with laboratory test values in 71 patients with JRA, 30 children with other rheumatic diseases, and 138 children without rheumatic disease. Results. Serum levels of HA showed significant correlation with the severity of joint symptoms, but not with systemic symptoms, in patients with systemic and polyarticular JRA. No other laboratory tests, including C-reactive protein and erythrocyte sedimentation rate, reflected the severity of joint symptoms. This correlation of serum levels of HA with joint symptoms was observed in patients with systemic and polyarticular JRA, but not in pauciarticular JRA, other rheumatic diseases, or nonrheumatic diseases, even when signs of arthritis were present in the latter 3 groups. Conclusion. Serum levels of HA are useful in objectively evaluating arthritic symptoms in patients with systemic and polyarticular JRA, and may have diagnostic value in this disease.