Evaluation of apoptosis in peripheral blood lymphocytes of renal transplant patients

The aim of this study was to evaluate the occurrence of apoptosis and the expression of FasL and IL-2 genes in apoptotic peripheral blood mononuclear cells (PBMC) at different posttransplant periods. Three groups of patients were studied: group 1, kidney transplant recipients at least 1 year posttransplant (n = 17); group 2, kidney transplant recipients at least 5 years posttransplant (n = 15); and a control group composed of 7 healthy subjects. Apoptosis was detected by annexin flow cytometry and gene expression by reverse transcription polymerase chain reactions. The percentage of apoptotic cells was significantly higher in groups 1 (42 +/- 4%) and 2 (37 +/- 3%) than the controls (27 +/- 2%; P < .0001). Apoptotic cells in group 1 was significantly higher than in group 2 (P < .005). A significant difference in FasL expression was observed between groups 1 and 2 (P < .001) and the immunosuppressive regimen. These findings suggest that PBMC of kidney transplant recipients are more susceptible to activation-induced cell death and that the Fas-FasL pathway is involved in this process.