Molecular studies of DO alleles reveal that JO is more prevalent than HY in Brazil, whereas HY is more prevalent in New York.

Because of the scarcity of anti-Hy and anti-Jo(a), hemagglutination typing for the Dombrock blood group system antigens, Hy and Jo(a), is not feasible. The molecular bases associated with these antigens have been determined, making it possible to distinguish HY and JO from wild-type DO. This provides a tool to predict the probable phenotype of patients and to screen for antigen-negative donors. PCR-RFLP assays and a microchip assay were used to determine the frequency of HY and JO alleles in donors from Brazil and New York. DNA from random Brazilian donors, 288 by PCR-RFLP and 599 by the bead array method (BeadChip, BioArray Solutions, Warren, NJ), was tested to determine 323G/T (HY+/HY-) and 350C>T (JO+/JO-) single-nucleotide polymorphisms. In New York, 27,226 donors who self-identified as being African American were tested by hemagglutination with anti-Gy(a). Nonreactive and weakly reactive samples were tested by PCR-RFLP for the same alleles as listed above. In Brazil, 30 (3.4%) of the samples were JO/DO and 13 (1.4%) were HY/DO. In New York, of the samples that had HY or JO alleles, 14 were homozygous HY/HY 132 were heterozygous HY/DO, 13 were heterozygous HY/JO, 14 were heterozygous JO/DO, and 3 were homozygous JO/JO. These results show that in donors from Brazil, JO (30 alleles) is more than twice as prevalent as HY (13 alleles), whereas in donors from New York, HY (173 alleles) was more than five times more common than JO (33 alleles).

LISS-dependent autoantibody with apparent anti-U specificity.

Nonspecific binding of gamma globulin and complement, resulting in falsely positive indirect antiglobulin tests, has occurred with use of low-ionic strength saline solution (LISS) reagents. These LISS-dependent antibodies have not been described in association with any particular disease state, nor do they have any apparent clinical significance. We present a LISS-dependent antibody with apparent autoanti-U specificity.

DNA analysis for donor screening of Dombrock blood group antigens.

Due to the scarcity of reliable antibodies, RBC typing for Doa and Dob is notoriously difficult. Inaccurate typing can place patients at risk for hemolytic transfusion reactions. The molecular basis of the DOA/DOB polymorphism is associated with three nucleotide changes:378 C>T, 624 T>C,and 793 A>G of DO. While the 378 C>T and 624 T>C are silent mutations, the 793A>G polymorphism in codon 265 encodes asparagine for Doa and aspartic acid for Dob. We describe here the use of a PCR-RFLP assay as an alternative to traditional hemagglutination for typing donor blood for Dombrock. Primers were designed to amplify the region of DO containing the 793A>G polymorphism. DNA samples from blood donors were amplified and subjected to RFLP analysis. A total of 613 samples were tested for the Dombrock polymorphism (793 A>G) by PCRRFLP. PCR-RFLP can be used to screen for Do(a-) or Do(b-) donors. This approach overcomes the scarcity of the reagents required for testing by hemagglutination.

DNA from blood samples can be used to genotype patients who have recently received a transfusion.

BACKGROUND: The use of hemagglutination to phenotype red cells from recently transfused patients or of red cells that are coated with IgG can be time-consuming and difficult to interpret. Because the molecular bases of many blood group antigens are known, it was investigated whether polymerase chain reaction (PCR) analysis of DNA, from white cells in blood from transfused patients, could be used to predict the blood group antigen profile of a patient. STUDY DESIGN AND METHODS: To prevent problems arising from potentially poor-quality DNA in clinical samples, primers that flanked the polymorphism of interest and that replicated a relatively short PCR amplicon were used. The PCR products, with or without digestion with the appropriate restriction enzyme, were analyzed on gels. Samples were collected from 60 patients who had received from 2 to 50 units of RBCs in the 7 days before sample collection. RBCs from some of these patients were coated with IgG. Analyses for RHD/non-D, RHE/RHe, KEL1/KEL2, FYA/FYB, FY-GATA, JKA/JKB, and GYPA M/N were performed by using assays that had been validated with DNA prepared from untransfused volunteers of known phenotype. The genotyping assays were performed without knowledge of the expected result. RESULTS: The predicted genotype after analysis of the 60 patient samples was that expected from the results of phenotyping. In all cases, the molecular analysis gave a single result; no evidence of chimerism was obtained. CONCLUSION: In each case, the molecular genotype results were in agreement with the blood group antigen as determined by historical phenotyping, phenotyping after hypotonic washing, detection of alloantibodies in the patient's serum, or elution of alloantibody(ies). Under the conditions of these assays, reliable determination of a blood group allele can be made by PCR-restriction fragment length polymorphism testing.