T-cell adhesion to endothelial cells in systemic lupus erythematosis

To investigate the pathogenesis of the lymphopenia in systemic lupus erythematosus (SLE), we examined the adhesion of these T cells to endothelial cells (EC). T cells from 10 lymphopenic patients with active SLE showed significantly reduced adhesion to unstimulated and interleukin-1 (IL-1)-stimulated human EC monolayers when compared with T cells from age, sex, and race matched normal control individuals. Percentage decreases from control values (delta) in the measured percentage of T cells adherent to unstimulated and IL-1-stimulated EC were 36.4% (P less than 0.025) and 34.0% (P less than 0.005), respectively. Percentage adhesion of phorbol ester-treated T cells of SLE patients was also reduced compared with similarly treated T cells of control patients; the decrease was 22.8% (P less than 0.025). No abnormality was detected in the adhesion to EC of T cells from patients with asthma who were receiving corticosteroids, suggesting that the abnormality in the SLE T cells was related to the disease process itself. The reduced adhesion of the circulating T cells may be a consequence of the withdrawal from the blood of more strongly adherent cells in the course of the inflammatory response. The loss of strongly adherent lymphocytes may contribute to the lymphopenia of SLE.