No abstract

Background: The provision of compatible blood products to patients is the most essential task of transfusion medicine. Besides ABO and Rh, a number of additional blood group antigens often have to be considered for the blood supply of immunized or chronically transfused patients. It also applies for platelet antigens (HPA) and neutrophil antigens (HNA) for patients receiving platelet or granulocyte concentrates. Here, we describe the molecular screening for a number of blood group, HPA, and HNA alleles. Based on the screening results we are building up a regional blood donor registry to provide extended matched blood products on demand. Methods: We developed and validated TaqMan™ PCR and PCR-SSP methods for genetic markers defining 37 clinically relevant blood group antigens (beyond ABO and Rh), 10 HPA, and 11 HNA. Furthermore, we describe a feasible method for fast molecular screening of the HNA-2^null phenotype. All data were statistically evaluated regarding genotype distribution. Allele frequencies were compared to ExAC data from non-Finnish Europeans. Results: Up to now more than 2,000 non-selected regular blood donors in south-west Germany have been screened for blood group, HPA, and HNA alleles. The screening results were confirmed by serology and PCR-SSP methods for selected numbers of samples. The allele frequencies were similar to non-finnish Europeans in the ExAC database except for the alleles encoding the S, HPA-3b and HNA-4b antigens, with significantly lower prevalence in our cohort, as well as the LU14 and the HNA-3b antigens, with a higher frequency compared to the ExAC data. We identified 71 donors with rare blood groups such as Lu(a+b-), Kp(a+b-), Fy(a-b-) and Vel-, and 169 donors with less prevalent HPA or HNA types. Conclusion: Molecular screening for blood group alleles by using TaqMan™ PCR is an effective and reliable high-throughput method for establishing a rare donor registry.

Background: The ABO blood groups result from DNA sequence variations, predominantly single nucleotide and insertion/deletion polymorphisms (SNPs and indels), in the ABO gene encoding a glycosyltransferase. The ABO blood groups A1, A2, B and·predominantly result from the wild type allele A1 and the major gene variants that are characterized by four diallelic markers (261G>del, 802G>A, 803G>C, 1061C>del). Here, we were interested to evaluate the impact of ABO genotyping compared to ABO phenotyping in paternity testing. Methods: The major ABO alleles were determined by PCR amplification with sequence-specific primers (PCR-SSP) in a representative sample of 1,335 blood donors. The genotypes were compared to the ABO blood groups registered in the blood donor files. Then, the ABO phenotypes and genotypes were determined in 95 paternity trio cases that have been investigated by 12 short tandem repeat (STR) markers before. We compared statistical parameters (PL, paternity likelihood; PE, power of exclusion) of both blood grouping approaches. Results: The prevalence of the major ABO alleles and genotypes corresponded to the expected occurrence of ABO blood groups in a Caucasian population. The low resolution genotyping of 4 diallelic markers revealed a correct genotype-phenotype correlation in 1,331 of 1,335 samples (99.7%). In 60 paternity trios with confirmed paternity of the alleged father based on STR analysis both PL and PE of the ABO genotype was significantly higher than of the ABO phenotype. In 12 of 35 exclusion cases (34.3%) the ABO genotype also excluded the alleged father, whereas the ABO phenotype excluded the alleged father only in 7 cases (20%). Conclusion: In paternity testing ABO genotyping is superior to ABO phenotyping with regard to PL and PE, however, ABO genotyping is not sufficient for valid paternity testing. Due to the much lower mutation rate compared to STR markers, blood group SNPs in addition to anonymous SNPs could be considered for future kinship analysis and genetic identity testing.