BACKGROUND: The D antigen of the polymorphic Rh blood group system is of particular clinical importance regarding transfusion- and pregnancy-induced alloimmunization. Different RhD variants with specific clinical implications have been characterized. The least expressed D variants collectively called DEL are serologically detectable only by adsorption-elution techniques, with so far only poorly defined antigenic properties. STUDY DESIGN AND METHODS: A comprehensive immunohematologic analysis of five of the six currently known DEL genotypes was performed. DEL phenotypes associated with the RHD(M295I), RHD(IVS3+1g>a), RHD(K409K), RHD(X418L), or RHD(IVS5-38del4) allele were characterized with extended serology and flow cytometry. RESULTS: Epitope mapping with adsorption-elution revealed a prominent D epitope loss in the RHD(IVS3+1g>a)-associated DEL phenotype, whereas in the other four DEL types no signs of qualitative D antigen alteration were detected. The observation of alloanti-D in two RHD(IVS3+1g>a) cases confirmed the partial nature of this DEL phenotype. The RHD(M295I) phenotype exhibited the highest D antigen expression among all investigated DEL types, as determined by a semiquantitative adsorption-elution approach and flow cytometry. CONCLUSION: In conclusion, evidence is provided that different DEL genotypes code either for partial or complete D antigen expression and that this finding is clinically relevant.
BACKGROUND: The D antigen of the polymorphic Rh blood group system is of particular clinical importance regarding transfusion- and pregnancy-induced alloimmunization. Different RhD variants with specific clinical implications have been characterized. The least expressed D variants collectively called DEL are serologically detectable only by adsorption-elution techniques, with so far only poorly defined antigenic properties. STUDY DESIGN AND METHODS: A comprehensive immunohematologic analysis of five of the six currently known DEL genotypes was performed. DEL phenotypes associated with the RHD(M295I), RHD(IVS3+1g>a), RHD(K409K), RHD(X418L), or RHD(IVS5-38del4) allele were characterized with extended serology and flow cytometry. RESULTS: Epitope mapping with adsorption-elution revealed a prominent D epitope loss in the RHD(IVS3+1g>a)-associated DEL phenotype, whereas in the other four DEL types no signs of qualitative D antigen alteration were detected. The observation of alloanti-D in two RHD(IVS3+1g>a) cases confirmed the partial nature of this DEL phenotype. The RHD(M295I) phenotype exhibited the highest D antigen expression among all investigated DEL types, as determined by a semiquantitative adsorption-elution approach and flow cytometry. CONCLUSION: In conclusion, evidence is provided that different DEL genotypes code either for partial or complete D antigen expression and that this finding is clinically relevant.
Authors: Neil D Avent; Antonio Martinez; Willy A Flegel; Martin L Olsson; Marion L Scott; Núria Nogués; Martin Písăcka; Geoff L Daniels; Eduardo Muñiz-Diaz; Tracey E Madgett; Jill R Storry; Sigrid Beiboer; Petra M Maaskant-van Wijk; Inge von Zabern; Elisa Jiménez; Diego Tejedor; Monica López; Emma Camacho; Goedele Cheroutre; Anita Hacker; Pavel Jinoch; Irena Svobodova; Ellen van der Schoot; Masja de Haas Journal: Transfus Med Hemother Date: 2009-05-28 Impact factor: 3.747