Changes in serum chondroitin sulphate epitopes 3-B-3 and 7-D-4 in early rheumatoid arthritis

Abstract

Objective. The aims of the present rheumatoid arthritis (RA) study were (1) to examine the levels of serum 3-B-3 and 7-D-4 to find out whether they are different from controls, (2) to find out whether the concentrations of these epitopes change with disease duration in early RA and (3) whether the serum concentrations of 3-B-3 and 7-D-4 in early RA are prognostic for subsequent disease progression. Methods. The concentrations of 3-B-3 and 7-D-4 in sera were quantitated by immunoassays. Results. The levels of 3-B-3 and 7-D-4 were significantly lower in RA than in controls (3- to 30-fold, P < 0.001). Changes in 3-B-3 and 7-D-4 were apparent with disease duration. At first presentation, the 3-B-3 concentration was lowest and increased at 12 months (3-fold, P < 0.001). This increase was transient since by 24 and 36 months the concentrations were not different to those at first presentation. The level of 7-D-4 was also lowest when the patients first presented at clinic and increased with time at 6 months (2-fold, P < 0.001). The increase was more prolonged for 7-D-4, remaining elevated at 12, 24 and 36 months. The lack of correlations of serum 3-B-3 and 7-D-4 with clinical measurements showed that these markers were not prognostic for discase severity. Conclusions. The levels of 3-B-3 and 7-D-4 differed between RA and control sera, and changed with disease duration. These markers were not prognostic in predicting disease outcome.