Methodological and clinical aspects of alloimmunization after granulocyte transfusion in patients undergoing...

In allogeneic hematopoietic stem cell transplantation (HSCT), granulocyte transfusions (GT) may be required in immunocompromised, neutropenic patients. In this context, alloimmunization against alloantigens may occur and affect HSCT outcome. Anti-human leukocyte antigen (HLA) and -MHC class I chain related antigens A (MICA) antibody response after the administration of GT in 29 patients undergoing allogeneic HSCT (n = 27) encompassing 109 sera was investigated by multianalyte microbead assay before and up to 6 month after HSCT. Anti-HLA class I and II antibodies emerged de novo in 11 (38%) and 4 (14%) patients, respectively. Similarly, preformed antibodies were observed in four cases (14%) for anti-HLA class I and also four patients for anti-HLA class II antibodies. Anti-MICA antibodies were observed in eight granulocyte recipients of which three patients developed anti-MICA antibodies after GT, whereas preformed antibodies were seen in five patients. The conversion to positivity for any of the investigated antibodies did not significantly affect overall survival or the incidence of GVHD. GT-associated alloantibody conversion observed did not significantly correlate with outcome. Thus, surveillance of anti-HLA antibodies in the course of GT in the context of HSCT may not be required routinely. The role of MICA antibodies in HSCT and GT, however, requires further study.