Understanding the Mechanisms of Platelet Alloimmunization and its Prevention

Abstract

Abstract : The purpose of our experiments is to identify methods of preventing alloimmunization to donor platelets in a dog platelet transfusion model. We have established DLA Class II typing to select antigen incompatible donor-recipient pairs for our transfusion experiments. In addition, we are evaluating potential allostimulatory WBC that must be removed to prevent platelet alloimmunization or WBCs that must remain to induce tolerance to donor platelet transfusions. Flow cytometry techniques using antisera that detect various classes of WBCs are being used to identify cells that are removed versus those that remain using different leukoreduction filters. The results of these white cell characterization studies will be correlated with the results of donor platelet transfusion experiments where different filters have been used to leukoreduce donor platelets prior to transfusion. Our current platelet transfusion experiments have evaluated gamma-irradiation alone or combined with leukoreduction to prevent alloimmunization to donor platelets. These experiments have demonstrated that none of these methods prevent platelet alloimmunization. Our next experiments will combine UV-irradiation along with filtration leukoreduction to determine if this combination can prevent alloimmune platelet refractoriness.