[Increased levels of circulating hyaluronate in the sera of patients with rheumatoid arthritis with special reference to joint destruction]

We sought to assess whether serum levels of hyaluronate (HA) in patients with rheumatoid arthritis (RA) are elevated and correlated with grade of joint destruction and with laboratory data. Circulating HA levels were determined by protein binding assay of serum from 236 patients and 19 healthy controls. The greatest elevations of HA were seen in RA patients (350.7 +/- 689.5 ng/ml) than controls (33.7 +/- 24.2 ng/ml). Their levels showed only weak correlation values of CRP in laboratory data. Although HA levels of sera in stage III and IV in Steinbrocker's classification revealed significantly higher on average than ones in stage I and II (p0.01), there were many cases with low HA levels even in stage III and IV. Comparing HA levels between the cases with progressive and non-progressive type of hip or knee joint destruction within a year, the former (1143.6 +/- 1746.0 ng/ml median 480.1 ng/ml) presented significantly higher HA levels than the latter (245.3 +/- 255.8 ng/ml median 140.0 ng/ml) (p0.01). Further, one of 7 cases followed by 4 years with extremely high levels of HA showed progression of joint destruction from grade III to IV in Larsen Grade in bilateral knee joints during these times, though there were no significant correlations between HA levels and laboratory data. From above results, levels of circulating HA in the sera of patients with RA correspond to the joint destruction, not to a result of one.