The ratios of CD11a, CD18, HLA-DP on T cells and CD54 on B cells of 54 patients with active systemic lupus erythematosus (SLE) were examined. The ratios of LFA-1 alpha, beta, ICAM-1, HLA-DP among SLE patients were significantly higher when compared with normal healthy controls, and the significant correlation between the ratio of LFA-1+ T cells and HLA-DP+ T cells, and LFA-1+ T cells and ICAM-1+ B cells was recognized. These results may suggest that LFA-1, ICAM-1 is related to the mutual action between activated T cells and B cells.