Sex-associated differences in organ transplantation: different effects of steroid hormones, testosterone, estradiol, progesterone, and prednisolone on the survival time of allogeneic skin graft in rats treated with cyclosporin A.

Adult male recipients could accept allogeneic skin graft with CyA treatment alone for considerably long periods, whereas young male and female, and adult females were not susceptible to the immunosuppression. When testosterone or prednisolone was administered with CyA as a combination therapy to young male and adult female recipients, the survival time of the graft was significantly prolonged. On the contrary, estradiol totally inhibited the immunosuppressive activity of CyA in any recipients. These present data strongly suggested that immunoreactivity against transplantation antigens can be influenced by sex steroid hormones, and that the usage of steroid combination therapy may overcome the lack of immunosuppression by CyA induced by the female sex steroid estradiol.