A possible role of apoptosis for regulating autoreactive responses in systemic lupus erythematosus

It has been reported that apoptotic cells are increased in the peripheral b lood from patients with systemic lupus erythematosus (SLE), where dysfuncti ons of T helper 1 (Th1) cells are known. In order to study whether apoptosi s of Th1 cells is associated with the pathogenesis of SLE, early apoptotic cells in various T-cell subsets were detected using fluorescence-labeled an nexin V (AnV). AnV binding was most frequently observed in CD4(+)CCR5(+) T cells, and AnV binding rate (%) in this subset was higher in SLE than in no rmal controls (14.7 +/- 2.6), although that in active SLE (43.6 +/- 7.3) te nded to be lower than that in inactive SLE (48.0 +/- 6.8). CD95/Fas express ion was also increased in both active and inactive SLE. In some SLE patient s, AnV binding rate changed in inverse proportion to titer of the serum ant i-DNA antibody and in proportion to serum complement activity. These data s uggest that apoptosis in Th1 cells is important in the pathogenesis of SLE and might play a role in regulating over-activation or autoreactive respons es by T cells.