Ultraviolet B irradiation in the prevention of alloimmunization in a dog platelet transfusion model

BACKGROUNDAlloimmune platelet (PLT) refractoriness remains a significant problem for chronically transfused patients with thrombocytopenia. STUDY DESIGN AND METHODSIn a dog PLT transfusion model, we evaluated ultraviolet B irradiation (UV-B) of donor PLTseither alone or in combination with centrifuge leukoreduction (C-LR) or filtration leukoreduction (F-LR)to prevent refractoriness to donor PLTs and to induce tolerance to standard (STD) PLTs from the same donor or to tertiary donors. RESULTSRecipient acceptance rates for C-LR donor PLT transfusions were 14%, F-LR were 33%, and UV-B irradiated were 45% with no significant differences among the treatments given to the donor's PLTs. Adding UV-B irradiation to C-LR or F-LR PLTs increased acceptance rates to 50 and 68% (p=0.02 and p=0.05), respectively, comparing single treatments to the combined treatments. After a recipient had accepted any type of UV-B-treated donor PLTs, specific tolerance to subsequent transfusions of the same donor's STD PLTs averaged 65%. Nonspecific tolerance to third-party donor's STD PLTs averaged 36% if they had accepted their initial donor's treated PLTs but was only 4% (p<0.001) if they had rejected these PLTs. CONCLUSIONCombining UV-B irradiation with a method of leukoreduction produces additive effects on prevention of alloimmune PLT refractoriness.