SERUM HYALURONATE IN RHEUMATOID-ARTHRITIS - STUDY BY AFFINO-IMMUNOENZYMATIC ASSAY

Serum level of hyaluronate (HA) was assayed by an affino-immunoenzymatic method using hyaluronectin, in 25 patients with rheumatoid arthritis (RA), 24 patients with ankylosing spondylitis (AS) and 103 controls. The mean serum HA level was significantly higher (p < 0.001) in RA (171 .+-. 39 .mu.g/l) than in controls (22.4 .+-. 1.6 .mu.g/l) and AS patients (30.3 .+-. 3.0 .mu.g/l). The mean HA level in RA on corticosteroids (98.2 .+-. 25.9 .mu.g/l) was significantly lower (p < 0.05) than that of RA without steroids (220.1 .+-. 60.5 .mu.g/l). The serum HA levels were not correlated with clinical or serological indicators of inflammatory activity. This increase in serum HA probably reflected an excessive production by rheumatoid synovium and not a lowered catabolism, all patients having normal hepatic function. The origin of the increased synthesis is still unknown. These results suggest that serum hyaluronate is not a universal indicator of inflammation but is perhaps a characteristic of RA.