COMPARABLE HISTOLOGICAL APPEARANCE OF SYNOVITIS IN SEROPOSITIVE AND SERONEGATIVE RHEUMATOID-ARTHRITIS

Objective and methods. To compare the histological characteristics of the synovium between seropositive and seronegative rheumatoid arthriti s (RA), synovial tissue was obtained from 19 patients with rheumatoid factor-positive (RF+) RA, 11 with rheumatoid factor-negative (RF-) RA and 11 non-RA controls. Results. There were no differences in the freq uency of each histological feature or histological scores between RFand RF-RA. However, significant differences in the frequency of histol ogical findings such as lining cell proliferation and inflammatory cel l infiltration were found both between RF+ RA and non-RA controls, and between RF- RA and non-RA controls. Analysis of clinical parameters, and histology in all RA patients revealed that the level of serum C-re active protein 2 and the erythrocyte sedimentation rate were directly correlated with the inflammatory cellular infiltration score. hn,Immun ohistological staining staining a monoclonal antibody against IgM rheu matoid factor (RF) was positive in some plasma cells in the synovium o f both RF+ and RF- RA patients, while no IgM-RF-positive cells were ob served in the synovium of non-RA controls Conclusion. RF serostatus do es not necessarily reflect the histology of synovial inflammation.