Sex-specific immune features may contribute to the physiological characteristics of the female allograft that cause higher graft rejection rates.
Male-specific minor histocompatibility antigens and sex hormone-mediated effects on immune function may affect graft outcomes in female graft recipients.
Hormone-mediated characteristics of male and female alloimmune responses may be amenable to selective estrogen receptor modulators and additional pharmacological methods of sex hormone receptor modulation.
Transplantation outcomes are known to be affected by multiple factors, including donor and recipient sex. Aside from the physiological characteristics of male and female donor allografts, accumulating evidence suggests that additional features underlie sex-specific immune responses that affect graft survival. We discuss here aspects of innate and adaptive alloimmunity that are specific to males and females in the context of underlying genetic and hormonal factors. These differences likely contribute to the observed disparities in graft survival. Understanding these features in more detail may lead to improved strategies for optimizing the results of organ transplantation.