Male recipients of kidneys from female donors are at increased risk of graft loss from both rejection and technical failure

The aim of the present retrospective study was to uncover the factor(s) res ponsible for the poor outcome of cadaver kidney grafts from female donors i n male recipients. The 741 transplantations performed at our center from August 1983 to Septem ber 1997 were distributed into four groups according to recipient and donor gender: female donor to female recipient (F to F: n = 117, male donor to f emale recipient (M to F: n = 172), female donor to male recipient (F to M: n = 170), and male donor to male recipient (M to M: n = 282). All the patie nts received immunosuppressive therapy based on corticosteroids and cyclosp orine, associated or not with either azathioprine or prophylactic anti-lymp hocyte globulin. Overall graft survival was lower in the F to M group than in the three othe r groups (p = 0.009). Failures due to rejection were more frequent during t he Ist post-transplant trimester in female than in male donor grafts, irres pective of recipient gender (p = 0.025). All failures due to technical prob lems occurred during the first 3 months post-transplantation: they were mor e frequent in the F to M group than in the three other groups (p = 0.040); this could be related to the older age of the donors in the former group. A fter the first post-transplant year, failures due to causes other than reje ction remained low in the F to F group but increased steadily in the three other groups (p = 0.007). Specific survival rates were not correlated with the time-evolution of mean serum creatinine values, daily doses and trough levels of cyclosporine in the four groups of grafts. In conclusion, the poo r outcome of F to M grafts results from combined immunologic and technical factors exerting their effects early in the course of transplantation.