LYMPHOCYTE-ACTIVATION STATUS, EXPRESSION OF ADHESION MOLECULES AND ADHESION TO HUMAN ENDOTHELIUM IN RHEUMATOID-ARTHRITIS - RELATIONSHIP TO DISEASE-ACTIVITY

The synovial tissue of patients with rheumatoid arthritis (RA) is char acterized by infiltration with inflammatory cells, mainly memory helpe r cells (CD4(+)CD29(+)). An important initiating step in tissue infilt ration is the adhesion of peripheral blood lymphocytes to the vascular endothelium. Therefore, we studied lymphocyte-endothelium adhesion in 40 RA patients and in 19 controls by a sensitive fluorimetric assay, using human umbilical vascular endothelial cells. Furthermore, express ion of adhesion molecules VLA (CD29) and LFA-1 (CD11a) on CD4(+) and C D8(+) T cells was determined. In order to evaluate the activation stat e of lymphocytes, the soluble interleukin-2 receptor (sIL2R) was measu red. The relationship to disease activity was evaluated using the Ritc hie articular index. RA patients had a higher percentage of CD4(+) cel ls (p < 0.005) and a lower percentage of CD8(+) cells (p < 0.001) than controls did. The CD4(+)CD29(+)/CD4(+)CD29(-) ratio and the CD8(+)CD2 9(+)/CD8(+)CD29(-) ratio were increased in patients with active RA (p < 0.01 and p < 0.05, respectively) and in patients with inactive disea se (p = 0.09 and p < 0.005, respectively) compared with controls. LFA- 1 (CD11a) was present on almost all T lymphocytes and its density did not differ between patients and controls. Serum levels of sIL2R were s ignificantly higher in both patient groups compared with controls (p < 0.0005); patients with active disease showed significantly higher lev els than patients with inactive disease (p < 0.05). Lymphocyte-endothe lium adhesion was not increased in patients, although the expression o f the adhesion molecule CD29 on T lymphocytes of RA patients was highe r. These results demonstrate that peripheral blood lymphocytes of RA p atients are activated, especially in patients with active disease, as demonstrated by elevated sIL2R levels and increased numbers of CD29(+) cells. Nevertheless, there was no increased lymphocyte adhesion to en dothelial cells in RA patients compared with controls. demonstrating t hat functional adhesion properties are not always correlated with the mere presence of CD29 or other adhesion molecules on the cell membrane .