Alloimmunization to donor platelets is common in transfused, immunosuppressed oncology patients. Leukoreduction reduces alloimmunization by more than half. Researchers recently investigated different methods to further reduce alloimmunization after platelet transfusion including leukoreduction with different filters, γ-irradation and Mirasol pathogen reduction using a dog transfusion model. Using a highly immunogenic model, most donor/recipient dog pairs were antigen incompatible (88%), and transfusions occurred weekly for up to 8 weeks or until platelet refractoriness occurred. Almost half of the dogs transfused (6/13, 4%) with leukoreduced platelets did not develop platelet refractoriness. Neither γ-irradiation nor Mirasol pathogen reduction alone prevented alloimmune platelet refractoriness. γ-irradation in combination with other methods also was not successful. However, leuko filtration of donor platelets followed by Mirasol pathogen reduction was successful in preventing alloimmune platelet refractoriness in 31/32 (97%) of dog recipients, and recipients did not develop antibodies to donor white blood cells. Mirasol pathogen reduction of platelets is approved in Europe and is awaiting approval in the United States. This approach deserves further study, especially in immunocompetent patients.
1. Slichter SJ, Pellham E, Bailey SL, Christoffel T, Gettinger I, Gaur L, Latchman Y, Nelson K, Bolgiano D. Leukofiltration plus pathogen reduction prevents alloimmune platelet refractoriness in a dog transfusion model. Blood 2017;130 (8); 1052-1060.