To investigate serum derived hyaluronan (HA) associated protein-hyaluronan (SHAP-HA) complex in sera from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and determine levels of the complex in comparison with those of hyaluronan (HA), in order to assess the role of the complex as an indicator of joint inflammation.
ELISA and HA binding assays were used for quantitation of the SHAP-HA complex and HA levels in serum samples from 142 patients (114 with RA, 28 with OA) and 31 healthy controls. Clinical evaluations were also performed.
In some RA sera, SHAP-HA complex levels were extremely high compared to control levels, but in OA sera no marked increase was observed compared to controls. This was also the case with the HA levels compared between RA and OA sera. However, in RA the levels of the SHAP-HA complex appear to be more related to clinical variables than are levels of HA, and the most significant correlations between levels of SHAP-HA complex and HA were found in the RA group.
Quantitation of the SHAP-HA complex in sera may be useful as a joint marker that directly correlates to the degree of joint inflammation in RA, and offers new insight into the pathogenesis of arthritis. It may also serve as an independent criterion in the subsequent classification of RA and OA.