Platelet transfusion refractoriness in highly immunized beta thalassemia children undergoing stem cell transplantation

Abstract

Marktel S, Napolitano S, Zino E, Cappelli B, Chiesa R, Poli F, Crocchiolo R, Ronchi P, Rossini S, Ciceri F, Roncarolo MG, Fleischhauer K. Platelet transfusion refractoriness in highly immunized beta thalassemia children undergoing stem cell transplantation.Pediatr Transplantation 2010: 14:393–401. © 2010 John Wiley & Sons A/S. Abstract: Immune-mediated refractoriness to platelet transfusion is a major problem in patients undergoing HSCT. In a cohort of 50 pediatric patients affected by beta thalassemia coming from Middle East countries, we experienced a high incidence of refractoriness because of anti-HLA antibodies during post-HSCT aplasia. In a risk factors analysis, factors predicting a negative transfusion outcome were presence of spleen and the number of anti-HLA antibodies. We adopted a policy to select platelet donors by avoiding HLA antigens against which the patient had specific antibodies. Transfusion of dedicated units resulted in 26% refractoriness compared to 74% to random units (p < 0.0001). When dedicated transfusions were used, the presence of spleen did not influence transfusion outcome. Analyzing transfusion outcome depending on the degree of HLA match and ABO compatibility, 76% successful transfusions were obtained with HLA-matched- ABO compatible followed by 67% in HLA-1mismatch- ABO compatible or HLA-matched- ABO incompatible and by 46% in HLA-1mismatch- ABO incompatible. In conclusion, we provide evidence that the selection of platelet donors according to patient characteristics, anti-HLA antibodies and ABO matching, is successful in reducing platelet refractoriness in heavily alloimmunized thalassemia patients undergoing transplantation.