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 characterized by infiltration with inflammatory cells, mainly memory helper cells (CD4+CD29+). An important initiating step in tissue infiltration 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, expression of adhesion molecules VLA (CD29) and LFA-1 (CD11a) on CD4+ and CD8+ T cells was determined. In order to evaluate the activation state of lymphocytes, the soluble interleukin-2 receptor (sIL2R) was measured. The relationship to disease activity was evaluated using the Ritchie articular index. RA patients had a higher percentage of CD4+ cells (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+CD29+/CD8+CD29- ratio were increased in patients with active RA (p < 0.01 and p < 0.05, respectively) and in patients with inactive disease (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 significantly higher in both patient groups compared with controls (p < 0.0005); patients with active disease showed significantly higher levels than patients with inactive disease (p < 0.05). Lymphocyte-endothelium adhesion was not increased in patients, although the expression of the adhesion molecule CD29 on T lymphocytes of RA patients was higher.(ABSTRACT TRUNCATED AT 250 WORDS)