Evaluation of the applicability and effectiveness of a molecular strategy for identifying weak D and DEL phenotype among D– blood donors of mixed origin exhibiting high frequency of RHDΨ

• Published in: Transfusion (Philadelphia, Pa.) Pa.), 2018-02, Vol.58 (2), p.317-322
• Main Authors: Dezan, Marcia Regina, Guardalini, Luis Giovani O., Pessoa, Elaine, Ribeiro, Ingrid Helena, Oliveira, Valeria Brito, Luz, Fabio, Novac, Denise Rossite, Gallucci, António, Bonifácio, Silvia, Gomes, Francisco, Levi, José E., Pereira, Alexandre C., Krieger, Jose E., Mendrone‐Junior, Alfredo, Rocha, Vanderson, Dinardo, Carla Luana
• Format: Article
• Language: English
• Subjects: Alleles; Blood Donors; Blood Grouping and Crossmatching - methods; Brazil; Female; Gene Frequency; Genotyping Techniques - methods; Humans; Male; Polymerase Chain Reaction - methods; Rh-Hr Blood-Group System - genetics
• ISSN: 0041-1132; 1537-2995
• DOI: 10.1111/trf.14425

BACKGROUND Molecular tests designed to detect the presence of active RHD gene among D– donors have been successfully applied in people of European ancestry, but not in admixed populations with a considerable frequency of RHD*Ψ. Our goal was to evaluate the performance of a molecular screening tool for identifying active RHD alleles among Brazilian blood donors classified as D– C+ and/or E+. STUDY DESIGN AND METHODS Pools of five DNA samples of serologically D– C+ and/or E+ donors were checked by a RHD polymerase chain reaction (PCR) assay specific for RHD Intron 4 and Exon 7. When a pool result was positive, samples were genotyped individually for RHD Intron 4 and Exon 7, RHD*Ψ, RHCE*Cc, and RHD zygosity. Donors suspected of active RHD gene were further evaluated by whole‐coding region and flanking intron direct sequencing. RESULTS A total of 405 donors were included. Two percent exhibited active RHD gene, codifying D‐weak (38 and 45) or DEL phenotype. The most prevalent DEL allele was RHD*DEL1 (c.1227G>A), which is proven to be immunogenic. A high frequency of RHD*Ψ was detected in the donors with nondeleted RHD alleles (31%), far superior to the frequency of RHD variant alleles (15.5%). The proposed approach presented sensitivity of 100% and specificity of 85.7% for identifying active RHD gene. CONCLUSION The strategy of checking D– donors with RHD PCR followed by exclusion of RHD*Ψ allele has proved efficient in identifying weak‐D and DEL phenotype in the Brazilian population.