“…The frequency of this complication in oncohematological patients varies depending on the study; in a recent analysis of the TRAP (Trial to Reduce Alloimmunization to Platelets) Study, platelet refractoriness developed in 27% of patients with acute leukemia ( 5 ) . In Brazil, a single center study published in 2004 describes an extremely high frequency, with 80% of patients developing this complication in the early phase of hematopoietic stem cell transplantation ( 6 ) . However, in a more recent study, a 19% frequency of platelet refractoriness, much closer to data of several other studies, was demonstrated among oncohematological patients ( 7 ) .…”