A Japanese multi-institutional collaborative study of antigen-positive red blood cell (RBC) transfusions in patients with corresponding RBC antibodies.

BACKGROUND AND OBJECTIVES: It is sometimes difficult to obtain antigen-negative red blood cells (RBCs) for patients with antibodies against RBCs. However, the frequency and severity of the adverse reactions have not been well elucidated. Here, we conducted a multi-institutional collaborative study to clarify the background, frequency and clinical significance of antigen-positive RBC transfusions to patients with the respective antibodies. MATERIALS AND METHODS: The survey included the background of patients, antigens on RBCs transfused, total amount of antigen-positive RBCs transfused, results from antibody screen and direct antiglobulin tests, specificity of antibodies, adverse reactions and efficacies. All antibodies were surveyed regardless of their clinical significance. RESULTS: In all, 826 cases containing 878 antibodies were registered from 45 institutions. The main reasons for antigen-positive RBC transfusions included 'negative by indirect antiglobulin test' (39%) and 'detection of warm autoantibodies' (25%). In 23 cases (3% of total), some adverse reactions were observed after antigen-positive RBC transfusion, and 25 antibodies (9 of 119 clinically significant and 16 of 646 insignificant antibodies) were detected. Non-specific warm autoantibodies were detected in 9 cases, anti-E in 5 cases, 2 cases each of anti-Lea , anti-Jra or cold alloantibodies, and 1 case each of anti-Dib , anti-Leb or anti-P1. Other antibodies were detected in 2 further cases. Five (22%) of these 23 cases, who had anti-E (3 cases) or anti-Jra (2 cases), experienced clinically apparent haemolysis. CONCLUSIONS: Adverse reactions, especially haemolysis, were more frequently observed in cases with clinically significant antibodies than those with clinically insignificant antibodies (P < 0·001).

Demonstration of A antigen and A allele of ABO histo-blood group in nail in a case with the absence of A antigen and anti-A antibody in blood.

We report a case with the inconsistency that the red blood cells lacked both A- and B-antigens while the serum showed reactivity with control B-red cells but not with A-red cells. A- and B-antigens were examined by serological blood typing and immunohistochemical staining, and DNA analyses were performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), DNA sequencing, and hot-stop PCR. A-antigens were demonstrable in the nail of the subject by serological study and immunostaining. DNA analyses showed that the nail retained a small amount of A-allele comparing to that of O-allele. Those genomic analyses of ABO genes were useful for demonstration of A allele in the nail of an individual with the absence of A antigen on red blood cells and the corresponding antibody in serum.

Transcription starting from an alternative promoter leads to the expression of the human ABO histo-blood group antigen.

BACKGROUND: Using the 5'-rapid amplification of cDNA ends technique with the ex vivo culture of AC133-CD34+ cells, a transcription start site was recently identified approximately 0.7 kb upstream from the transcription start sites previously determined. The transcripts from the alternative starting exon 1a were demonstrated in the cells of both erythroid and epithelial lineages. Because the nucleotide sequence of exon 1a does not contain an ATG codon, we examined whether transcription starting from exon 1a leads to production of a functional glycosyltransferase. STUDY DESIGN AND METHODS: Stable transfection experiments into the human gastric cancer MKN28 cells were performed using the various A transferase expression plasmids. RESULTS: Large amounts of A antigens were demonstrated on the cells transfected with the A transferase expression plasmid containing the entire cDNA from exon 1a or the 5'-truncated cDNA leading to the production of the N-truncated protein with deletion of the cytoplasmic tail and a portion of the transmembrane domain. However, negligible amounts of A antigens were observed on the cells transfected with the A transferase expression plasmids containing the 5'-truncated cDNA leading to the production of the N-truncated proteins without the cytoplasmic tail and the transmembrane domain. CONCLUSION: This study suggests that a functional A transferase could be produced by the transcription from exon 1a.