Genotyped RhD+ red cells for D-positive patients with sickle cell disease with conventional RHD and unexpected anti-D.

Anti-D can occur in D-positive patients who inherit RHD genetic variants encoding partial D antigen expression, but unexpected anti-D is also found in the plasma of patients with sickle cell disease who have conventional RHD gene(s) and are transfused with units from Black donors. These anti-D are likely stimulated by variant Rh expressed on donor cells; however, patients with anti-D, regardless of cause, are transfused for a lifetime with D-negative (Rh-negative) blood. This results in significant increased use of Rh-negative units, especially for those requiring chronic transfusion, which can strain Rh-negative blood inventories.

RH genotypes and red cell alloimmunization rates in chronically transfused patients with sickle cell disease: A multisite study in the USA.

Background: Red cell alloimmunization remains a challenge for individuals with sickle cell disease (SCD) and contributes to increased risk of hemolytic transfusion reactions and associated comorbidities. Despite prophylactic serological matching for ABO, Rh, and K, red cell alloimmunization persists, in part, due to a high frequency of variant RH alleles in patients with SCD and Black blood donors.

Study Design And Methods: We compared RH genotypes and rates of alloimmunization in 342 pediatric and young adult patients with SCD on chronic transfusion therapy exposed to >90,000 red cell units at five sites across the USA.

International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology Report of Basel and three virtual business meetings: Update on blood group systems.

Background And Objectives: Under the ISBT, the Working Party (WP) for Red Cell Immunogenetics and Blood Group Terminology is charged with ratifying blood group systems, antigens and alleles. This report presents the outcomes from four WP business meetings, one located in Basel in 2019 and three held as virtual meetings during the COVID-19 pandemic in 2020 and 2021.

Materials And Methods: As in previous meetings, matters pertaining to blood group antigen nomenclature were discussed.

Impact of RHD genotyping on transfusion practice in Denmark and the United States and identification of novel RHD alleles.

Background: Reduced D antigen on red blood cells (RBCs) may be due to "partial" D phenotypes associated with loss of epitope(s) and risk for alloimmunization or "weak" D phenotypes that do not lack major epitopes with absence of clinical complications. Genotyping of samples with weak and discrepant D typing is recommended to guide transfusion and RhIG prophylaxis. The goal was to compare the impact of RHD genotyping on transfusion practice in two centers serving different populations.