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Background: Hematopoietic stem cell transplant (HSCT) is currently the only widely available curative option for patients with sickle cell disease (SCD). Alloimmunization in this population is frequent and can complicate transfusion management during the HSCT period. The case of a pediatric patient with severe SCD clinical phenotype, multiple alloantibodies (9), and hyperhemolysis syndrome who underwent haploidentical HSCT is described. Study Design and Methods: The patient was known for an anti‐e, despite RHCE*01.01 allele, which predicts a C‐ c+ E‐ weak e+ phenotype. Donors matching the patient's extended phenotype were targeted for RHCE genotyping. Results: Donors homozygotes or heterozygotes for RHCE*01.01 were selected for compatibility analyses and ranked based on strength of reactions. Discordance between zygosity and strength of reactions was observed, as the most compatible donors were heterozygotes for RHCE*01.01. In total, the patient received seven RBC units from two different donors during HSCT process without transfusion reaction or development of new alloantibodies. Six months post‐HSCT, his hemoglobin level is stable at around 120 g/L and his chimerism is 100%. Discussion: This case highlights the complexity of transfusion management during HSCT of alloimmunized patients with SCD. Collecting sufficient compatible units requires early involvement of transfusion medicine teams and close communication with the local blood provider. Genotyping of donors self‐identifying as Black is useful for identifying compatible blood for those patients but has some limitations. HSCT for heavily alloimmunized patients is feasible and safe with early involvement of transfusion medicine specialists. Further research on the clinical impact of genotypic matching is needed. [ABSTRACT FROM AUTHOR]

Aim: More data is required regarding the association between HLA allele and red blood cell (RBC) antigen expression in regard to SARS-CoV-2 infection and COVID-19 susceptibility. Methods: ABO, RhD, 37 other RBC antigens and HLA-A, B, C, DRB1, DQB1 and DPB1 were determined using high throughput platforms in 90 Caucasian convalescent plasma donors. Results: The AB group was significantly increased (1.5×, p = 0.018) and some HLA alleles were found to be significantly overrepresented (HLA-B*44:02, C*05:01, DPB1*04:01, DRB1*04:01 and DRB1*07:01) or underrepresented (A*01:01, B51:01 and DPB1*04:02) in convalescent individuals compared with the local bone marrow registry population. Conclusion: Our study of infection-susceptible but non-hospitalized Caucasian COVID-19 patients contributes to the global understanding of host genetic factors associated with SARS-CoV-2 infection and severity. [ABSTRACT FROM AUTHOR]

Background: The determination of the RhD phenotype is crucial to avoid alloimmunization, especially in childbearing women. Following the 2015 recommendation from the Work Group on RHD Genotyping, a large‐scale RHD genotyping program was implemented in the province of Quebec (Canada) and offered to women ≤45 years old with a serological weak D or discordant results. Since weak D type 42 was previously shown to be prevalent among French Canadians, genotyping for that variant was also performed. Our aim was to report the prevalence of the weak D alleles in the province of Quebec. Study Design and Methods: A retrospective study of 2105 women with serological weak D referred to Hema‐Quebec's immunohematology reference laboratory (IRL) between June 2016 and May 2020 was conducted. Results from the serological tests performed by the referring hospital were compiled and RHD were genotyped. Results: Most patients presented at least one serological result ≤2+ before being referred to Hema‐Quebec. Weak D type 42 was the most prevalent variant, representing 17.5% (368/2105) of all individuals tested. Only 15.3% (323/2105) of patients were weak D type 1, 3.3% (69/2105) were type 2, and 8.6% (180/2105) were type 3. Weak D type 42 is highly expressed in regions with low immigration rate and known for their founder effect. Conclusion: Our RHD genotyping program allowed for a better management of weak D. The province of Quebec presents a unique RHD genotype distribution. We confirmed that weak D type 42 is associated with a founder effect found in Caucasian French Canadians. [ABSTRACT FROM AUTHOR]

Background: A global downtrend in blood usage has been observed by many countries, while the demand for antigen‐negative red blood cell (RBC) units used in antigen‐matched transfusions keeps increasing. The declining number of units collected exposes blood providers to a rapidly evolving supply challenge. Methods: This study was conducted retrospectively with use of internal data analysis to weigh Québec's situation regarding global and antigen‐negative RBC demand, to measure the effects of community‐directed recruitment and blood drives, and to evaluate the benefits of mass‐scale RBC genotyping. Results: Our findings confirm a global RBC usage downtrend of over 20% total in the past 10 years with a steady antigen‐negative usage and highlight the most requested negative antigen combinations. Our data also show our +39.5% progress regarding the number of Black donors recruited for antigen matching of patients with sickle cell disease in the past 3 years, as well as a constantly growing number of just‐in‐time blood collection for complex orders. Finally, our data summarize the efficiency of our mass‐scale RBC genotyping efforts. Conclusion: Altogether, this study confirms the demand trends for regular and antigen‐negative RBC units in Québec and the efficient effects of our recruitment and typing strategies. [ABSTRACT FROM AUTHOR]

The antibody reacted to trypsin-treated cells, but not to 200 mM DTT, which suggested the presence of an antibody against a high-frequency antigen of the Kell system. Abbreviations DTT dithiothreitol RBC red blood cell Kell is one of the most polymorphic blood group systems with 36 described antigens to date and is considered the most important blood group system after the ABO and Rh. [Extracted from the article]

A novel variant DO*A allele with a c.370delT mutation leading to a DO-null phenotype in a Syrian family The Dombrock antigens are clinically relevant blood group antigens, known for potentially causing delayed and acute hemolytic transfusion reactions, although no hemolytic disease of the fetus and newborn has been described.1,2 We report here a new DO allele in a family of Syrian origin caused by a c.370delT (p.Leu124Cys) nonsense mutation, leading to a DO-null phenotype (ISBT Allele Number I DO*01 N.05 i , GenBank Accession Number MT747635). In this report, we describe a novel I DO*A i allele (c.370delT [p.Leu124Cysfs*4]) involving a nonsense mutation, leading to absent expression of all Dombrock antigens or a DO-null phenotype. [Extracted from the article]