Generation of a human induced pluripotent stem cell line (YUCMi020-A) from peripheral blood mononuclear cells derived from a female with the Jr(a-) blood type.

The Jra antigen, the only antigen within the JR blood group system, is a high-prevalence red blood cell (RBC) antigen found in over 99 % of the global population. An induced pluripotent stem cell line (YUCMi020-A) was generated from peripheral blood drawn from a Jr(a-) phenotype individual, who was homozygous for a null mutation of ABCG2*01N.01 (rs72552713, c.376C>T; p.Gln126*). The generated line exhibited pluripotent characteristics and no chromosomal aberrations. This cell line will serve as a cell source, enabling us to produce RBCs with the Jr(a-) phenotype in vitro, which can be used for transfusing individuals with anti-Jra antibodies.

Evaluating the TaqMan Jra-Genotyping Method for Rapidly Predicting the Presence of Anti-Jra Antibodies.

Background: The Jra antigen is a high-prevalence red blood cell (RBC) antigen. Reports on cases of fatal hemolytic disease of the fetus and newborn and acute hemolytic transfusion reactions suggest that antibodies against Jra (anti-Jra) have potential clinical significance. Identifying anti-Jra is challenging owing to a lack of commercially available antisera. We developed an alternative approach to rapidly predict the presence of anti-Jra using the TaqMan single-nucleotide polymorphism (SNP)-genotyping method. Methods: Residual peripheral blood samples from 10 patients suspected of having the anti-Jra were collected. Two samples with confirmed Jr(a-) RBCs and anti-Jra were used to validate the TaqMan genotyping assay by comparing the genotyping results with direct sequencing. The accuracy of the assay in predicting the presence of anti-Jra was verified through crossmatching with in-house Jr(a-) O+ RBCs. Results: The TaqMan-genotyping method was validated with two Jr(a-) RBC- and anti-Jra-confirmed samples that showed concordant Jra genotyping and direct sequencing results. Jra genotyping for the remaining samples and crossmatching the serum samples with inhouse Jr(a-) O+ RBCs showed consistent results. Conclusions: We validated a rapid, simple, accurate, and cost-effective method for predicting the presence of anti-Jra using a TaqMan-based SNP-genotyping assay. Implementing this method in routine practice in clinical laboratories will assist in solving difficult problems regarding alloantibodies to high-prevalence RBC antigens and ultimately aid in providing safe and timely transfusions and proper patient care.

Corrigendum: Genetic diagnosis of inborn errors of immunity using clinical exome sequencing.

[This corrects the article DOI: 10.3389/fimmu.2023.1178582.].

Genetic diagnosis of inborn errors of immunity using clinical exome sequencing.

Inborn errors of immunity (IEI) include a variety of heterogeneous genetic disorders in which defects in the immune system lead to an increased susceptibility to infections and other complications. Accurate, prompt diagnosis of IEI is crucial for treatment plan and prognostication. In this study, clinical utility of clinical exome sequencing (CES) for diagnosis of IEI was evaluated. For 37 Korean patients with suspected symptoms, signs, or laboratory abnormalities associated with IEI, CES that covers 4,894 genes including genes related to IEI was performed. Their clinical diagnosis, clinical characteristics, family history of infection, and laboratory results, as well as detected variants, were reviewed. With CES, genetic diagnosis of IEI was made in 15 out of 37 patients (40.5%). Seventeen pathogenic variants were detected from IEI-related genes, BTK, UNC13D, STAT3, IL2RG, IL10RA, NRAS, SH2D1A, GATA2, TET2, PRF1, and UBA1, of which four variants were previously unreported. Among them, somatic causative variants were identified from GATA2, TET2, and UBA1. In addition, we identified two patients incidentally diagnosed IEI by CES, which was performed to diagnose other diseases of patients with unrecognized IEI. Taken together, these results demonstrate the utility of CES for the diagnosis of IEI, which contributes to accurate diagnosis and proper treatments.

In vitro erythrocyte production using human-induced pluripotent stem cells: determining the best hematopoietic stem cell sources.

BACKGROUND: Blood transfusion is an essential part of medicine. However, many countries have been facing a national blood crisis. To address this ongoing blood shortage issue, there have been efforts to generate red blood cells (RBCs) in vitro, especially from human-induced pluripotent stem cells (hiPSCs). However, the best source of hiPSCs for this purpose is yet to be determined. METHODS: In this study, hiPSCs were established from three different hematopoietic stem cell sources-peripheral blood (PB), cord blood (CB) and bone marrow (BM) aspirates (n = 3 for each source)-using episomal reprogramming vectors and differentiated into functional RBCs. Various time-course studies including immunofluorescence assay, quantitative real-time PCR, flow cytometry, karyotyping, morphological analysis, oxygen binding capacity analysis, and RNA sequencing were performed to examine and compare the characteristics of hiPSCs and hiPSC-differentiated erythroid cells. RESULTS: hiPSC lines were established from each of the three sources and were found to be pluripotent and have comparable characteristics. All hiPSCs differentiated into erythroid cells, but there were discrepancies in differentiation and maturation efficiencies: CB-derived hiPSCs matured into erythroid cells the fastest while PB-derived hiPSCs required a longer time for maturation but showed the highest degree of reproducibility. BM-derived hiPSCs gave rise to diverse types of cells and exhibited poor differentiation efficiency. Nonetheless, erythroid cells differentiated from all hiPSC lines mainly expressed fetal and/or embryonic hemoglobin, indicating that primitive erythropoiesis occurred. Their oxygen equilibrium curves were all left-shifted. CONCLUSIONS: Collectively, both PB- and CB-derived hiPSCs were favorably reliable sources for the clinical production of RBCs in vitro, despite several challenges that need to be overcome. However, owing to the limited availability and the large amount of CB required to produce hiPSCs, and the results of this study, the advantages of using PB-derived hiPSCs for RBC production in vitro may outweigh those of using CB-derived hiPSCs. We believe that our findings will facilitate the selection of optimal hiPSC lines for RBC production in vitro in the near future.

Comparative evaluation of Elecsys, Atellica, and Alinity assays for measuring the anti-Hepatitis C virus (HCV) antibody.

BACKGROUND: Hepatitis C virus (HCV) infection is a major cause of liver diseases in Korea. Anti-HCV assays are used to screen for HCV infection. Here, we assessed the agreement and diagnostic performances of three different anti-HCV assays. METHODS: We analyzed 1180 samples using three assay systems-Elecsys Anti-HCV II (Roche Diagnostics), Atellica IM aHCV (Siemens Healthineers), and Alinity s Anti-HCV (Abbott Diagnostics)-and evaluated the agreements between the results and diagnostic performances. RESULTS: The Cohens kappa coefficients between the Roche and Siemens, Siemens and Abbott, and Roche and Abbott systems were 0.837, 0.961, and 0.849, respectively. The Fleiss kappa coefficient among the three systems was 0.883. The sensitivities and positive predictive values were 86.5 and 89.8 for Roche, 97.5 and 98.1 for Siemens, and 99.4 and 98.2 for Abbott, respectively. The area under the curves of the anti-HCV signal to cutoff (S/Co) ratios or cutoff index for predicting viremia in the Roche, Siemens, and Abbott systems were 0.432, 0.641, and 0.676, respectively; the optimal S/Co ratio was 14.715 for Siemens and 14.42 for Abbott. CONCLUSIONS: All three assays showed excellent diagnostic performance; however, anti-HCV values need to be used with caution to predict viremia; therefore, supplementary tests are necessary to confirm viremia status, especially for samples with low values.