Correlation among automated scores of agglutination, antigen density by flow cytometry and genetics of D variants. (October 2019)

• Record Type: Journal Article
• Authors: Arnoni, Carine Prisco; Muniz, Janaína Guilhem; Vendrame, Tatiane Aparecida de Paula; Medeiros, Rosangela de; Cortez, Afonso José Pereira; Latini, Flavia Roche Moreira; Castilho, Lilian
• Is Part Of: Transfusion and apheresis science. Volume 58:Number 5(2019)
• Page Start: 680
• Page End: 684
• Publication Date: 2019-10
• Subjects: RhD variants -- Agglutination intensity -- Flow cytometry -- D expression -- RHD genotyping; Blood -- Transfusion -- Periodicals; Hemapheresis -- Periodicals; 615.39
• DOI: 10.1016/j.transci.2019.08.018
• Languages: English
• ISSNs: 1473-0502

Abstract

Abstract: Background: Laboratory testing to identify the molecular basis of serologic weak D phenotypes is recommended to determine whether a pregnant woman or potential transfusion recipient should be managed as RhD-positive or RhD-negative. The variation in D antigen expression on RBCs, different potencies of anti-D typing reagents, lack of standardized test methods, and the subjectivity of interpreting agglutination reactions complicate the detection of D variants. We evaluated the correlation of agglutination scores by an automated immunoassay analyzer with D antigen densities determined by flow cytometry, and D variant types identified by molecular analysis. Materials and methods: We selected 273 blood donor samples with agglutination scores of less than 92 (4+), measured by an automated analyzer (NEO®, Immucor, Norcross, GA, USA). D antigen densities were measured by flow cytometry for 89 samples. Samples were classified as molecularly-determined weak D or partial D variants by multiplex PCR, PCR RFLP and DNA sequencing. Results: All samples with a D antigen density ≥15% had an agglutination score >80 (4+). Agglutination scores for weak D types varied from 10 to 90. Agglutination scores for partial D antigens were graded with scores varying from 60 to 99. D antigen densities varied from 0.55% to 10.67% for weak Ds and 4.1% to 30.5% for partial Ds. Discussion: Our results showed that score values follow a pattern among D variants that could be related to antigen density and to the RhD variant classification.