All-male plasma makes UK TRALI tumble

October 2007
Feature Story

Anne Paxton

U.S. blood centers that have switched to all-male plasma to reduce TRALI cases usually say it is too early to predict the impact, but the policy has already had a promising proving ground in Great Britain. "Their rate of TRALI has been reduced by more than 75 percent, and their rate of fatal TRALI has plummeted by more than 90 percent," says Dr. James AuBuchon of Dartmouth-Hitchcock Medical Center.

Dr. Lorna Williamson of the National Blood Service division of NHS Blood and Transplant reports that her agency's hemovigilance program, called SHOT (Serious Hazards of Transfusion), has been monitoring TRALI in the UK since 1996.

"In 2002, we had enough cases to do an analysis of risk factors and components. It was clear by then that we were seeing an excess of TRALI associated with plasma and platelets compared to red cells, and these cases nearly always had an HLA-antibody-positive donor-all female. That was consistent with other evidence that somewhere between 10 and 15 percent of women who have had children have HLA antibodies in their plasma."

In 2002, the National Blood Service considered various options to minimize TRALI, one of which was to ask donors for a history of pregnancy, but with the number of other new donor questions relating to SARS and West Nile virus, that was not viewed as a practical option.

"We next considered switching totally to solvent detergent FFP [fresh frozen plasma] because that has a pretty good track record, probably because donors with HLA antibodies are diluted out in the pooling process," Dr. Williamson says. But because solvent detergent FFP was extremely expensive, "we finally settled on a very simple strategy to try to use only male donors for manufacture of FFP and also for suspension of pooled platelets."

Units would be marked M or F at the donor session, and when they came back to the blood center, the plasma from males would be used for FFP, and the female plasma would be discarded. (Because of variant Creutzfeldt-Jakob disease, the UK does not send plasma for fractionation as American blood centers do.)

In making the transition, it hasn't been possible to reach 100 percent male plasma yet, but plasma and pooled platelets are now about 80 to 90 percent male. The results were "quite encouraging," Dr. Williamson says; they show a marked and steady decline in TRALI cases:

In 2003, the baseline year, there were 36 cases of TRALI, of which 22 were highly likely or probable, and overall eight cases from platelets and eight from FFP.
In 2004, 23 cases of TRALI, of which 13 were highly likely or probable, and overall four were from platelets and six from FFP.
In 2005, 23 cases total, of which six were highly likely or probable, two from platelets and one from FFP.
In 2006, 10 cases total, of which three were highly likely or probable, one from platelets and one from FFP.

The number of TRALI cases related to red-cell transfusion, which involves far less plasma, has remained the same for all four years: one to three per year, Dr. Williamson says.

Anne Paxton is a writer in Seattle.