Gerbich-negative phenotypes of the Gerbich Blood Group System (ISBT 020) are very rare (with the exception of Papua New Guinea). The Gerbich-negative phenotypes Yus and Gerbich are negative for the antigens Ge2, and Ge2 and Ge3, respectively. In antigen-negative individuals, anti-Ge2 and anti-Ge3 antibodies can be naturally occurring, or are triggered during pregnancies and after transfusions. Previous studies suggested an elevated frequency of Gerbich-negative phenotypes for the Middle East. In the summer of 2015, a large-scale migration of people from the Middle East to Europe occurred raising the issue of question how to guarantee blood supply for patients and manage antenatal care for pregnant women from these countries.To investigate the frequency of rare Gerbich-negative phenotypes, 1,665 immigrants to Germany originating from the Middle East were genetically tested for the presence of rare Yus, i.e., GE*01.-02, and Gerbich, i.e., GE*01-03, alleles and compared to results obtained from 507 Germans.Seven Yus GE*01.-02.01 and one Gerbich GE*01.-03.02 alleles were exclusively observed among people from the Middle East, with five of them clustering among 797 Syrians. No such alleles were observed in Germans. A cumulative Yus- and GE*01.-03-type allele frequency of 0.00314 and resultant overall Gerbich-negative phenotype frequency of one among 101,633 Syrians were calculated.This manuscript describes for the first time an exclusively genetic screening for carriers of Gerbich-negative alleles. In conclusion, the Gerbich blood group system should be considered as one causative agent of unusual antibodies to red cell antigens, in routine patients and pregnant women, especially when originating from the Middle East.
Anti-G antibodies are rarely found since anti-D, in combination with anti-C, are difficult to discriminate from anti-G antibodies in routine testing.A 22-year-old, gravida-3, para-1, woman with blood group A Rh D neg ccddee and known antibody anti-Jk(b), gave birth to her second child. While anti-Jk(b) could not be detected at birth, a new anti-C was found. Antibody screening tests (IAT) were performed using gel cards and rare G positive rGr erythrocytes. Genotyping for RHD and RHCE was performed using PCR-SSP.The child's blood group was A Rh D neg Ccddee. Genotyping revealed Cde/cde haplotypes. The erythrocytes of the new-born showed a positive direct antiglobulin test with IgG; anti-D and anti-C could be eluted. Erythrocytes with the rare phenotype rGr were reactive with the serum of the mother.The presence of anti-D and anti-C in the eluate from then newborn's Ccddee erythrocytes proved anti-G or anti-G in combination with anti-D. When anti-C and anti-D are seen during a pregnancy, possibly anti-G is present. This observation is of relevance since women with anti-G can still develop anti-D and require rhesus prophylaxis.
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Abstract Background All antigens described in the KN blood group system are located in the long homologous repeat D (LHR‐D) of complement receptor 1 (CR1). While there have been reports that some sera react only with the long homologous repeat C (LHR‐C), the antigens in LHR‐C are unknown. Study Design and Methods Recombinant LHR‐C and LHR‐D were used to identify antibodies directed against LHR‐C of CR1, into which a point mutation was introduced to characterize the underlying blood group antigens. In addition, database studies to define haplotypes of CR1 were performed. Results Several antisera were identified that were specific against CR1 p.1208His and against CR1 p.1208Arg, located in LHR‐C. Fifteen KN haplotypes were found in the Ensembl genome browser. It was shown that due to a linkage disequilibrium anti‐CR1 p.1208His may be mistaken for anti‐KCAM. Conclusion A novel antithetical KN blood group antigen pair was found at position p.1208 of CR1, for which the names DACY and YCAD are proposed. Antibodies against these two novel antigens seem to contribute to more than a quarter of all KN sera in Europe.
