Male organs make better transplants
Donated organs from women are less successful than those from men in organ transplantation, a German study has found.
The study looked at more than 124,000 kidney, 25,000 heart and 16,000 liver transplants on the Collaborative Transplant Study database, and evaluated the graft survival depending on donor and recipient gender. Overall people who received an organ from a woman were less likely to have successful grafts, particularly if the organ donated was a kidney.
"It is a bit surprising," said Professor Hans Schlitt, the Head of Transplantation Surgery at the Royal Prince Alfred Hospital and the University of Sydney. "There was some data published for liver transplants one or two years ago which suggested similar results."
The researchers, led by Dr Martin Zeier, from the University of Heidelberg in Germany allowed for potential complicating factors such as the year of the donation, where the people lived, their race, and age.
The study found that women receiving a kidney from a female donor were 15 per cent more likely to lose the organ than if their donor had been a man. The situation was even more marked for men receiving kidneys from women, where the chances of losing the organ was 22 per cent.
The findings were reported in this week's news roundup in British Medical Journal.
"I think one of the explanations is that organs from female donors may tend to be a little smaller with a smaller nephron mass," said Schiltt. "We know that this plays a role in susceptibility to rejection and long term graft survival."
It is safer to transplant an adult's kidney into a child rather than a child's, he explained. The rule of thumb is the bigger the organ transplanted the better it is. "If there is more foreign tissue the less chance of rejection," said Schlitt.
The liver is less susceptible to rejection than the kidney because the
kidney is smaller, he said. The German study backed this up. In the case of liver transplants, where 16,410 transplants were assessed, there was no statistical difference between female and male donors.
Transplants of hearts also showed a difference between women and men. Men receiving a woman's transplanted heart are 13 per cent more likely to lose the heart than if their donor was a man. Women showed no difference between receiving women's or men's hearts.
This gender effect was more pronounced for younger (16 to 45 years)
donors compared to donors over 45 years. This age factor could imply a hormonal explanation for the result. "That is something that you cannot exclude completely," said Schlitt.
Organs donated by brain-dead people in Australia tend to be spilt evenly between men and women. World-wide the spilt of people who make live donations - of one of their kidneys or part of their liver, is two thirds women and one third men, said Schlitt.
The original study was published in the Journal of the
American Society of Nephrology.