Syndecan-4 is correlated with disease activity and serological characteristic of rheumatoid arthritis

To describe the feature of expression of syndecan-4 in serum, synovial fluid (SF) and synovium in rheumatoid arthritis (RA) patients, and to analyze the correlation of syndecan-4 with disease activity and serological characteristic of RA.

Syndecan-4 in sera of 60 RA patients, 20 osteoarthritis (OA) patients, 20 healthy controls, and in SF of 25 RA patients and 25 OA patients were tested by enzyme linked immunosorbant assay. The expressions of syndecan-4 in synovium of RA and OA patients were detected by immunohistochemistry. The expression of syndecan-4 on synovial fibroblasts from RA and OA patients were detected by immunofluorescence. The correlation between serum syndecan-4 concentration and disease activity were analyzed in RA patients.

The serum syndedcan-4 concentration was significantly higher in RA patients than in OA patients and healthy controls, and was higher in rheumatoid factor (RF)-positive RA patients than in RF-negative ones. Syndecan-4 concentration in SF of RA patients was comparable with OA patients. Syndecan-4 expression in synovial tissue was similar between RA and OA patients. The syndecan-4 concentration was significantly lower in SF than in serum of RA and OA patients. Syndecan-4 concentration in both serum and SF was positively correlated with disease activity of RA patients.

The serum syndecan-4 concentration was higher in RA patients than in OA patients, and significantly higher in RF-positive RA patients than in RF-negative ones. Syndecan-4 concentration in both serum and SF was positively correlated with disease activity of RA patients.