Aug. 13 (HealthDay News) -- Female kidney recipients whose donated organ came from a deceased male face an increased risk for failure in the first year after their transplant, Canadian researchers have found.

The risk is short-term, though, and may stem from proteins on male donor cells, the researchers said. Their study found that the risk goes away after 10 years.

The researchers analyzed data on 117,877 adults who had kidney transplants in the United States between 1990 and 2004. All kidneys came from deceased donors. Within a year, transplant failure had occurred in 16,135 people, and 6,878 had died. Among the 97,906 people who were followed for up to 10 years after their transplant, there were 35,084 transplant failures and 22,566 deaths.

Compared with all other gender combinations, female recipients of male donor kidneys had a 12 percent greater risk of failure and a similar increased risk for death a year after the transplant. They had no increased risk for failure or death after 10 years.

The researchers, from the University of Toronto and University of British Columbia, said that H-Y antigens, derived from the male chromosome and not found in women, might cause an adverse immune response in women who receive kidneys from men who had died.

They recommended that "future research should examine the potential mechanisms underlying the H-Y effect in order to better understand the specific role of minor histocompatibility antigens in determining kidney allograft outcomes."

The study is published online in the Journal of the American Society of Nephrology.

SOURCE: American Society of Nephrology, news release, July 2009