By David Weill, MD, Posted

Why Gender Matters in the Transplant Donor and Recipient

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.

Different hormones produced by men and women may influence the success of organ transplants, a new report finds. In a recently  published article in the journal Trends in Immunology the influence of gender in organ donors and recipients has been assessed. The study, led by surgeon Stefan Tullius from the Brigham and Women’s Hospital in Boston found that in kidney transplants, female organs were more often rejected than male ones – a trend higher among male recipients. In heart transplants, too, female organs were more often rejected, but in this case only in male recipients.

And while the gender bias in transplant rejection was by no means universal, it is considered significant.

“In solid organ transplantation, the importance and implications of the sex of both the donor and the recipient have long been underappreciated,” says Tullius. “The differences may be subtle but I think they are very relevant, particularly as we move toward individualizing immunosuppression and try to find ways to be more specific in our treatment. I think understanding the relevance of sex differences will play a significant role in this.”

The mechanisms influencing gender-determined transplant failure are still being examined, but Tullius and colleagues suggest sex chromosomes may be a factor. They note that X-chromosomes contain about 50 genes linked to immunological functions, and that these tend to be expressed more variably in women than in men. The Y-chromosome, found only men, contains locations that bond with male-only toxins, or antigens. These factors may influence immune cell functions after transplants. The researchers suggest therapies that target hormone receptors might in the future reduce the rate of gender-influenced transplant failure.

I find this study interesting and points toward an accumulating body of evidence that suggests gender matching (and mis-matching) of the donor and recipient may be a factor in outcomes. Because of the organ shortage and the fact that we always want to find organs for our waiting patients, gender has not been an important factor in choosing organs for a potential recipient. But perhaps in the future it should be.