What is the Incidence of Early Antibody Formation after Resuscitation of Hemorrhage? A Comparison of RH(D)+ Whole Blood and RH(D)- Red Blood Cells in 3,531 Trauma Patients.

Abstract

To evaluate the risk of red blood cell alloimmunization following transfusion of low-titer group O whole blood (LTOWB) compared with component therapy in severely injured trauma patients. LTOWB is increasingly used for trauma resuscitation because of logistical advantages and potential hemostatic benefits. However, concerns remain regarding alloimmunization, particularly anti-D antibody formation in Rh(D)-negative patients exposed to Rh(D)-positive blood products. A retrospective cohort study was conducted at a single Level I trauma center using trauma registry data from 2017-2023. Adult trauma patients (≥15 years) who received emergency release uncrossed blood products prehospital or shortly after admission were included. Patients were categorized by exposure to Rh(D)-positive LTOWB (WB group) or Rh(D)-negative component therapy alone (COMP group). Antibody screening was performed on admission and repeated at 72-hour intervals during hospitalization. The primary outcome was incidence of alloimmunization. A total of 3,531 patients met inclusion criteria, including 2,103 in the WB group and 1,428 in the COMP group. Post-transfusion alloantibody formation occurred in 3% of WB patients (n=63) and 2% of COMP patients (n=32). Among WB patients who developed alloantibodies, anti-D antibodies accounted for 11% of detected antibodies, with anti-E most common (22%). In the COMP cohort, anti-D antibodies accounted for 20% of detected antibodies. In both groups, alloantibody formation was more common in Rh(D)-negative patients. LTOWB transfusion in severely injured trauma patients was associated with a low incidence of alloantibody formation comparable to component therapy, supporting the immunohematological safety of LTOWB in trauma resuscitation.