We have studied the expression of human histo-blood group ABO genes during erythroid differentiation, using an ex vivo culture of AC133 ؊ CD34 ؉ cells obtained from peripheral blood. 5-Rapid amplification of cDNA ends analysis of RNA from those cells revealed a novel transcription start site, which appeared to mark an alternative starting exon (1a) comprising 27 bp at the 5-end of a CpG island in ABO genes. Results from reverse transcription-PCR specific to exon 1a indicated that the cells of both erythroid and epithelial lineages utilize this exon as the transcription starting exon. Transient transfection experiments showed that the region just upstream from the transcription start site possesses promoter activity in a cell type-specific manner when placed 5 adjacent to the reporter luciferase gene. Results from bisulfite genomic sequencing and reverse transcription-PCR analysis indicated that hypermethylation of the distal promoter region correlated with the absence of transcripts containing exon 1a, whereas hypermethylation in the interspersed repeats 5 adjacent to the distal promoter was commonly observed in all of the cell lines examined. These results suggest that a functional alternative promoter is located between the hypermethylated region of repetitive elements and the CpG island in the ABO genes.In 1900 Karl Landsteiner discovered the ABO blood group system, which is important in blood transfusions and personal identification in criminal investigations (1). Two carbohydrate antigens, A and B, and their antibodies constitute this system. The functional A and B alleles at the ABO genetic locus encode glycosyltransferases ␣133GalNAc transferase (A-transferase) and ␣133Gal transferase (B-transferase), respectively. A-transferase transfers a GalNAc residue from UDP-GalNAc to the precursor H substrate, producing A antigens as defined by the trisaccharide determinant structure GalNAc␣133-(Fuc␣132)Gal␤13 R. Similarly, B-transferase catalyzes the transfer of a Gal from UDP-Gal to the same H substrate, producing B antigens defined by Gal␣133(Fuc␣132)-Gal␤13 R (2-5). Molecular genetic studies of human ABO genes have demonstrated that ABO genes consist of at least seven exons spanning over 18 kb of genomic DNA and that two critical single base substitutions in the last coding exon result in amino acid substitutions responsible for the different donor nucleotide sugar substrate specificity between A-and B-transferases. A single base deletion in exon 6 was ascribed to shift the reading frame of codons and to abolish the transferase activity of A-transferase in most O alleles (6 -9).The ABO antigens are expressed in a cell type-specific manner; the isoantigens A, B, and H of blood groups A, B, and O are not confined to red cells but are also found in most secretions and on some epithelial cells. However, they are absent in connective tissues, muscles, and the central nervous system (10). Moreover, ABH antigens are known to undergo drastic changes during development, differentiation, and maturation of cells in epithe...

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PLT-derived mitochondrial DAMPs are candidate risk factors for the onset of NHTRs.

These results indicate that the K562 panel cell lines provide a good panel for detecting HNA-reactive neutrophil antibodies in human serum samples.

On transfusion, several plasma proteins can cause anaphylaxis in patients deficient in the corresponding plasma proteins. However, little is known about other allergens, which are encountered much more infrequently. Although it has been speculated that an allergen-independent pathway underlying allergic transfusion reactions (ATRs) is elicited by biological response modifiers accumulated in blood components during storage, the exact mechanisms remain unresolved. Furthermore, it is difficult even to determine whether ATRs are induced via allergen-dependent or allergen-independent pathways. To distinguish these two pathways in ATR cases, we established a basophil activation test, in which the basophil-activating ability of supernatants of residual transfused blood of ATR cases to whole blood basophils was assessed in the presence or absence of dasatinib, an inhibitor of IgE-mediated basophil activation. Three of 37 supernatants from the platelet concentrates with ATRs activated panel blood basophils in the absence, but not in the presence, of dasatinib. The basophil activation was inhibited by treatment of anti-fish collagen I MoAb in one case, suggesting that the involvement of fish allergens may have been present in donor plasma. We concluded that unknown non-plasma proteins, some of which had epitopes similar to fish antigens, in blood component may be involved in ATRs via an allergen/IgE-dependent pathway.

BackgroundThe involvement of xenotropic murine leukemia virus-related virus (XMRV) in prostate cancer (PC) and chronic fatigue syndrome (CFS) is disputed as its reported prevalence ranges from 0% to 25% in PC cases and from 0% to more than 80% in CFS cases. To evaluate the risk of XMRV infection during blood transfusion in Japan, we screened three populations--healthy donors (n = 500), patients with PC (n = 67), and patients with CFS (n = 100)--for antibodies against XMRV proteins in freshly collected blood samples. We also examined blood samples of viral antibody-positive patients with PC and all (both antibody-positive and antibody-negative) patients with CFS for XMRV DNA.ResultsAntibody screening by immunoblot analysis showed that a fraction of the cases (1.6-3.0%) possessed anti-Gag antibodies regardless of their gender or disease condition. Most of these antibodies were highly specific to XMRV Gag capsid protein, but none of the individuals in the three tested populations retained strong antibody responses to multiple XMRV proteins. In the viral antibody-positive PC patients, we occasionally detected XMRV genes in plasma and peripheral blood mononuclear cells but failed to isolate an infectious or full-length XMRV. Further, all CFS patients tested negative for XMRV DNA in peripheral blood mononuclear cells.ConclusionOur data show no solid evidence of XMRV infection in any of the three populations tested, implying that there is no association between the onset of PC or CFS and XMRV infection in Japan. However, the lack of adequate human specimens as a positive control in Ab screening and the limited sample size do not allow us to draw a firm conclusion.

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This pilot study indicates that the BAT may be useful in clarifying the causal relationship between ATRs and transfused blood as well as in elucidating the mechanisms behind ATRs considering the allergen/IgE-dependent pathway.