D+ platelet transfusions in D– patients: cause for concern?

Patients whose RBCs are D– may produce anti-D if they are exposed to D on donor RBCs. Except in emergency situations, patients whose RBCs lack D are transfused with only D– RBCs. Platelets carry no Rh antigens, but platelet units may be contaminated by RBCs that could carry D when these units are collected from D+ donors. The purpose of this study was to determine whether our policy of allowing D+ platelets to be transfused to patients whose RBCs type as D–, without the use of prophylactic Rh immunoglobulin (RhIG), results in D alloimmunization. The transfusion records of all patients who received platelet transfusions from December 2004 to March 2007 were reviewed. Transfusion recipients were evaluated with pretransfusion ABO and D typings, and an antibody screen. Recipients were reevaluated in the same manner before subsequent transfusions. Transfusion records of 114 D– patients were analyzed. Overall, 104 patients received D+ platelets; 67 had repeat antibody screening after transfusion. No patients were shown to make anti-D after platelet transfusion. There was no evidence of D alloimmunization as a result of transfusion of D+ platelets in any D– patient during this study. The data do not support the practice of restricting D– patients to receiving only D– apheresis platelets, even among patients with chronic transfusion requirements. Prophylactic use of RhIG for D+ apheresis platelet transfusions in D– patients also appears to be unnecessary. Immunohematology2009;25:5–8.