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Saturday, February 20, 2010

Female blood plasma may be safe

Contrary to current guidelines, it may be not only safe but beneficial to use blood plasma donated by women.

Heart surgery patients often require plasma transfusions. About one in every 3000 transfusions results in an extremely dangerous condition called ‘transfusion-related acute lung injury' (TRALI). There is some evidence that TRALI is linked to plasma that was donated by females. TRALI is thought to be an immune reaction, and female mammals, particularly ones who have been pregnant, contain antibodies to certain cell surface factors. Briefly, it was thought that the female antibodies were triggering a catastrophic immune reaction.

For this reason, in 2006 the AABB (formerly the American Association of Blood Banks) recommended that blood banks avoid using plasma from female donors.

Three years later, Mark Stafford-Smith and his team from Duke University Medical Center tested whether that advice was sound.

Even prior to the 2006 finding, the blood products from male and female donors have been kept separate. Stafford-Smith took advantage of this fact to search the records for cardiac patients who had been transfused with either female-only or male-only plasma. He identified 390 matched pairs. To his surprise, the female-only recipients actually had better outcomes. Although the long-term survival rates were similar, the female-only patients had just over half as many incidents of pulmonary dysfunction, death within 30 days of surgery, or extended hospitalization (more than ten days).

Meanwhile, female-plasma is still associated with TRALI. The researchers speculated that because TRALI is so rare, the negative effects of female plasma were overshadowed by the unexpected and thus far unexplained benefits.

To be clear, it’s the blood donors that were separated by gender, not the heart patients. This study did not distinguish between male or female patients who had been given male or female blood plasma, something I personally would have liked to see done. Also, the study only included heart patients. The doctors agree that more research is required before revising the current AABB recommendations. If the benefits of receiving female plasma can be more clearly understood and separated from the risks, this will be a boon for anyone requiring transfusion.