Increase in adhesion molecules on CD4+ cells and CD4+ cell subsets in synovial fluid from patients with rheumatoid arthritis.

OBJECTIVE

To elucidate the role of adhesion molecules in the pathogenesis of rheumatoid arthritis (RA).

METHODS

We evaluated their expression and that of an activation marker on CD4+ cell populations and CD4+ cell subsets in specimens of peripheral blood (PB) and synovial fluid (SF) obtained from 10 patients with RA and 7 with osteoarthritis (OA). A 2 or 3-color immunofluorescent method was used for analysis.

RESULTS

The SF from both groups of patients showed a greater density of adhesion molecules including LFA-1 alpha, LFA-1 beta, CD2, VLA-4 alpha and VLA-5 alpha on CD4+ cells, and a higher percentage of CD4+HLA-DR+ cells compared with their PB. IN PB-CD4+ cell subsets from the arthritic and healthy subjects, the CD4+CD45RO+ cell population showed an increased expression of adhesion molecules compared with CD4+CD45RA+ cell population. The expression of adhesion molecules on circulating CD4+ cell population and CD4+ cell subsets from the patients with RA and OA was comparable to that from healthy subjects. SF from both groups of patients showed a higher percentage of CD4+CD45RO+ cells and a lower percentage of CD4+CD45RA+ cells. In SF-CD4+ cell subsets from patients with RA, the CD4+CD45RO+ cell population had an increased expression of VLA-4 alpha compared to the CD4+CD45RA+ cell population; however, there was no significant difference in other adhesion molecule expression and the percentage of HLA-DR+ cells between the 2 cell subsets. Furthermore, the expression of VLA-4 alpha on the CD4+CD45RO+ cell population in SF from patients with RA was significantly higher than that in matched PB. In CD4+CD45RA+ cell population from both groups of patients, SF showed an enhanced expression of adhesion molecules and an increased percentage of HLA-DR+ cells compared with matched PB.

CONCLUSION

Our results suggest that increased expression of adhesion molecules and increased percentage of HLA-DR+ cells on CD4+ cells in SF may be responsible for cellular interactions between these cells and synovial cells or extracellular matrix.