(P-TS-12) Anti-D development between patients with and without history of solid organ transplant

Background/Case Studies: The D antigen on red blood cells is known to be highly immunogenic, thus prophylactic D matching is often performed during red cell transfusion to prevent alloimmunization. Solid organ transplant surgeries constitute high risk for blood loss and exclusively transfusing D-negative transplant recipients with D-negative red cells can deplete the D-negative inventory, especially at a time of frequent national blood shortages. The goal of this study was to compare the alloimmunization rate after D-mismatched red cell transfusions between patients with and without a history of solid organ transplant at a single center tertiary hospital.

Study

Design/Methods: D-negative patients who received ≥1 unit of D-positive red cells were identified using historical transfusion records. Historical antibody results were examined to determine formation rate of anti-D and any red cell alloantibodies, which were compared between patients with and without a history of transplant.

Results/Findings: Among 76 patients included in the analysis, 22 patients had a history of solid organ transplant. When formation of anti-D was compared, no transplant patients and 12 non-transplant patients developed new anti-D. When formation of any new red cell alloantibodies was compared, one of the transplant patients and 14 non-transplant patients developed new red cell antibodies.

Conclusions: Among our limited study population, we observed a lower likelihood of D alloimmunization among solid organ transplant patients. A larger, prospective study should be performed to evaluate the need for prophylactic D matching in red cell transfusions during solid organ transplant surgeries.

Importance of research: In addition to gender and age, transplant and immunosuppression history should also be considered when estimating risk of anti-D formation. Transfusion services can implement this by prospectively discussing bleeding risk and transfusion plan with the clinical team before transplant surgeries for D-negative patients without anti-D, in order to avoid depleting D-negative inventory in a setting with low alloimmunization risk and frequent national blood shortages.