Willy Albert Flegel

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy associated with a poor prognosis and an unmet need for more effective treatment options, particularly after relapse. One potential approach to address this need, which has been used successfully in solid tumors, is adoptive transfer of T cells engineered to express specific T cell receptors (TCRs). Particularly attractive are TCRs that can target epitopes derived from oncogenes on which cancer cells depend while sparing normal cells that do not harbor the mutation. One promising oncogenic target in AML is mutated nucleophosmin 1 (mtNPM1), present in up to 30% of AML cases. Most NPM1 mutations result in a common frameshifted sequence that generates peptides presented by several class I human leukocyte antigens (HLAs), such as HLA-A*11:01. In this study, we vaccinated HLA-A*11:01-transgenic mice with the mtNPM1 peptide AVEEVSLRK and isolated six functional TCRs from mtNPM1-reactive lymphocytes. When engineered into human T cells, two of these TCRs consistently mediated robust and specific lysis of an AML cell line and primary AML cells co-expressing HLA-A*11:01 and mtNPM1. Neither TCR recognized related human peptides, HLA-A*11:01-expressing normal peripheral blood mononuclear cells or stem/progenitor cells, or cells expressing diverse allogeneic HLAs, suggesting a low risk of cross-reactivity and alloreactivity. In an AML xenograft model, both TCRs controlled AML in hematopoietic organs, although extramedullary tumors emerged during treatment, potentially reflecting the aggressive behavior of the model that may not be representative of AML in patients. Together, these data suggest that the two TCRs represent strong candidates for further preclinical development in adoptive T cell therapy for NPM1-mutated, HLA-A*11:01-positive AML. These results also support the use of HLA-transgenic mice as a platform for generating TCRs targeting oncogene-derived epitopes in hematologic malignancies.

Background: Demand for O RhD-negative red cells continues to rise, while overall red cell transfusions have decreased, compounding inventory management challenges. We analyzed O RhD-negative red cell utilization in a large publicly available database. Methods: Data from 378,855 red cell transfusions were evaluated using the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III). Utilization patterns, recipient demographics, and their correlation with the age of red cell units at transfusion were examined. Results: The majority of O RhD-negative units were transfused to patients with blood groups other than O RhD-negative (54.5%). A larger percentage of O RhD-negative red cells were transfused after 35 days of collection (41%), compared to other blood groups (18.7%). Patients over 50 years, males, non-O RhD-negative and RhD-positive individuals had higher odds of receiving units stored more than 35 days. Patients with higher hemoglobin concentrations were more likely to receive older blood units. Discussion: The analysis identified opportunities to improve the allocation of O RhD-negative red cell units, highlighting current inventory practices as suboptimal. The findings call for refined allocation strategies to improve the utilization of this limited resource. The implementation of real-time management approaches may balance the retention of such red cell units with the needs of patients who benefit from the use of RhD-negative blood.

Accurate typing of the D antigen is critical to provide guidance for blood transfusion and safe management of Rh-incompatible pregnancies. RHD genotyping a

Background/aim: Red cell cryopreservation is essential for immunohematology reference laboratories. Various cryopreservation methods maintain the structural integrity of red cells, such as bulk freezing with glycerol and droplet freezing with polyvinylpyrrolidone (PVP). In this paper, we provide a technical note with real-world data and report our experience with a modified PVP bulk-freezing method in a transfusion medicine setting.Materials and methods. Red cells were separated from whole blood samples and incubated for 1 h at room temperature with PVP with slow agitation or no agitation before freezing. Instead of using the established method of shock freezing droplets in liquid nitrogen, the red cells were frozen as 1 mL bulk samples. Recovery rates were determined for different thawing temperatures.Results. The overall red cell recovery rate was 45%±9% (mean±standard deviation). The recovery rates were 42.3%±8.1% in samples incubated without agitation (n = 27) and 47.9%±9.3% with slow agitation (n = 24) before freezing (p = 0.017). The recovery rates at different thawing temperatures, were 34.0%±2.0% at 22 °C, 46.6%±9.3% at 37 °C, and 40.8%±4.9% at 42°C (p=0.007). A generalized linear model confirmed that slow agitation during incubation yielded higher recovery than no agitation (p = 0.029).Conclusion. Bulk freezing of red cells with PVP in liquid nitrogen yielded 45% recovery. Our modified method may be preferred for cryopreservation and storage of large volumes. Bulk freezing with PVP can be particularly useful in applications where maximizing storage efficiency is more important than minimizing cell loss.

Background and Objectives: The International Society of Blood Transfusion (ISBT) Working Party (WP) on Red Cell Immunogenetics and Blood Group Terminology (RCI&BGT) held six business meetings between December 2021 and June 2024. This report describes the new blood group systems and antigens ratified during these meetings. Materials and Methods: Candidate systems and antigens were reviewed according to serological, genetic and biological evidence. This evidence was matched against defined criteria, and the acknowledged systems/antigens were assigned a unique identifier. Results: Four new systems, ER (ISBT 044), CD36 (ISBT 045), ATP11C (ISBT 046) and MAL (ISBT 047), were ratified. CD36 and ATP11C were de novo entries, while ER and MAL systems resolved the genetic basis for the Er and AnWj antigens. Thirteen antigens were added to existing systems: one each to LU (005), YT (011), SC (013), LW (016), KN (022), GLOB (028); an antithetical pair to KEL (006); two antigens to RHAG (030); and three to CTL2 (039). Two CTL2 antigens defined the hitherto unresolved antithetical antigens, Cs ^a /Cs ^b , whose genetic basis coincides with those of variants responsible for the HNA‐3a/3b neutrophil antigens, respectively. Conclusion: As of June 2024, the ISBT has acknowledged 47 blood group systems, comprising 366 antigens. The WP continues to ratify new systems and antigens, which are available on the ISBT website ( http://www.isbtweb.org/working-parties/red-cell-immunogenetics-and-blood-group-terminology/ ).

Background: CD59 is a GPI‐anchored glycoprotein on the surface of many cell types. It inhibits the assembly of the membrane attack complex, thus preventing complement‐mediated cell lysis. Lack of a functional CD59 protein causes recurrent ischemic strokes, neuropathy, and chronic hemolysis. We aimed at a comprehensive analysis of the CD59 gene from publicly available databases to identify variants and evaluate their pathophysiologic potential.Methods: Variants in the CD59 coding sequence of exons 4, 5, and 6 and their splice sites were systematically compiled from 4 major populations across 6 whole‐genome and whole‐exome databases. The PredictSNP algorithm assessed the functional impact of non‐synonymous variants.Results: Among 488,592 individuals, 160 distinct alleles were identified in 6881 subjects (0.7%). Among 93 alleles with non‐synonymous variants, 43 were classified as deleterious and 49 (2 variants encoded the same amino acid change) as neutral by PredictSNP. Additional variants included: 53 synonymous, 9 deletions/duplications, 3 splice site, and 2 nonsense. Among the 14 non‐synonymous variants reported in patient samples, 9 were classified as deleterious (64.3%) and 5 as neutral (35.7%).Discussion: We collated a list of CD59 variants, which were classified as neutral or deleterious by PredictSNP, from genome databases. These results can be applied to identify individuals with possible latent CD59 deficiency symptoms, such as hemolytic transfusion reactions. In conjunction with clinical data, these CD59 variants can guide personalized clinical decisions.