Effect of intravenous cyclophosphamide in systemic lupus erythematosus: relation to lymphocyte subsets and activation markers

Since the mechanism mediating the beneficial effect of intravenous cyclopho sphamide (IVCY) in systemic lupus erythematosus (SLE) is unknown, we invest igated lymphocyte subsets and markers of activated lymphocytes in patients received IVCY, and compared the results with the effect of steroid pulse. I n 55 patients with SLE, 34 patients receiving IVCY [2] cases (61.8%) were r esponsive] and 25 patients received steroid pulse [2] cases (84.0%) were re sponsivce] (four patients who were resistant to steroid pulse therapy were transferred to IVCY). When the lymphocyte subsets and markers of activated lymphocytes were compared in the responsive and unresponsive group of IVCY, soluble CD4 levels and the ratio of HLA-DP-positive T cells were significa ntly higher in the unresponsive group. Further, the changes of these marker s and costimulatory molecules [LFA-1 (CD11a). ICAM-1 (CD54), CD40 and CD40- ligand (CD154)] were also examined in the responsive patients. The ratio of HLA-DP-positive T cells did not change in the IVCY-responsive group, while it decreased in the steroid pulse therapy-responsive group. The ratio of C D11a on T cells increased and CD54 on B cells decreased in the: IVCY-respon sive group. The ratio of CD154 on T cells increased in the steroid pulse-re sponsive group, while it decreased in the IVCY-responsive group. These resu lts suggest that the effect of IVCY is different to that of steroid pulse t herapy and mainly related to B cell activation, and that these markers may contribute to predict the responsiveness of IVCY.