Anti-D alloimmunization after D-incompatible platelet transfusions: a 14-year single-institution retrospective review

A small, but immunogenic dose of red blood cells (RBCs) may be contained in apheresis platelets (PLTs). Attempts are made to provide D- recipients with D- PLTs to prevent anti-D alloimmunization and the potential for hemolytic disease of the fetus and newborn. Beth Israel Deaconess Medical Center has a policy that when necessary to transfuse D+ PLTs to D- patients, we recommend that RhIG be given when the patient is a woman of child-bearing age or a potential liver transplant patient. We sought to retrospectively determine the rate of anti-D formation after D-incompatible apheresis PLT transfusions in those patients not receiving RhIG and not receiving D+ RBCs over a 14-year period at our institution.

All D- patients (626) who received D+ prestorage leukoreduced apheresis PLTs between January 1, 1997, and December 31, 2011, were identified. Those patients who received RhIG (45), D+ RBC transfusions (50), or stem cell transplantation from a D+ donor (16); had prior anti-D (23); or had unresolved Rh at admission (8) were not eligible for analysis. Only those patients who had an antibody screen performed at least 4 weeks after the incipient PLT transfusion were evaluated (130).

Of 130 eligible D- patients, 48% women and 57% immunocompetent, who received a total of 565 apheresis PLTs, none formed anti-D.

These findings support the use of D+ apheresis PLTs without RhIG irrespective of D status in all recipients.