A study of two decades of liver transplants by University of Pittsburgh researchers appears to show that a good histocompatibility match between donor and recipient lowers the risk of organ rejection, but ironically increases the likelihood of a recurrence of hepatitis C or primary biliary cirrhosis.

The report, presented at the annual American transplant scientific meeting in Washington, DC, appears to suggest that transplant doctors may be better off taking their chances on rejection -- which generally can be dealt with today -- and transplanting less compatible livers into patients with hepatitis C or primary biliary cirrhosis.

"This is particularly significant for hepatitis C, the most common indication for liver transplantation and where the absolute majority of the patients suffer recurrence after transplantation," said Dr. John J. Fung, chief of transplant surgery. "Perhaps by paying attention to histocompatibility we may be able to reduce the numbers,"

Unlike the case with kidney transplants, where surgeons have long tried to achieve the best possible histocompatibility match between donor and recipient, most transplant doctors have felt that histocompatibility matching was not as important for livers -- with the need to transplant livers more rapidly making it largely irrelevant anyway.

Instead, surgeons have paid closer attention to blood type compatibility and the size of the liver relative to the recipient. But researchers at the University of Pittsburgh have been collecting information on histocompatibility as part of an extensive database since 1981.

What they found was that a good histocompatibility match significantly decreases the incidence of acute and chronic rejection, reported Igor Dvorchik, research assistant professor of biostatistics.

But they also found that having a match put patients with hepatitis C or primary biliary cirrhosis (PBC) at greater risk for disease recurrence, while perhaps more important, a histocompatibility mismatch significantly decreased the risk of recurrence of these diseases.

For patients with hepatitis C, 50 percent who had at least one match with their donor of the HLA-B molecule had recurrence of their disease within two years, the researchers reported. But only 25 percent of those patients with mismatches had recurrence of disease within the same time period.

For primary biliary cirrhosis (PBC), which tends to recur later, 35 percent of PBC patients with two HLA-DR matches had disease recurrence at five years, compared to 10 percent of PBC patients with no matches or just one match, the researchers said.

They found that the histocompatibility matching or mismatching appeared to have little impact on recurrence of hepatitis B or other types of liver diseases.

"This is valuable information for surgeons to consider in deciding the appropriateness of using donor organs in some of our patients," said Fung. "But whether HLA testing will become routine for liver transplantation remains to be seen."

But it might well become routine, researchers suggest, as part of the testing testing for living donor liver transplants when the recipient has hepatitis C or PBC.

Other sources: University of Pittsburgh