Development and validation of a universal blood donor genotyping platform: a multinational prospective study.

Each year, blood transfusions save millions of lives. However, under current blood-matching practices, sensitization to non-self-antigens is an unavoidable adverse side effect of transfusion. We describe a universal donor typing platform that could be adopted by blood services worldwide to facilitate a universal extended blood-matching policy and reduce sensitization rates. This DNA-based test is capable of simultaneously typing most clinically relevant red blood cell (RBC), human platelet (HPA), and human leukocyte (HLA) antigens. Validation was performed, using samples from 7927 European, 27 South Asian, 21 East Asian, and 9 African blood donors enrolled in 2 national biobanks. We illustrated the usefulness of the platform by analyzing antibody data from patients sensitized with multiple RBC alloantibodies. Genotyping results demonstrated concordance of 99.91%, 99.97%, and 99.03% with RBC, HPA, and HLA clinically validated typing results in 89 371, 3016, and 9289 comparisons, respectively. Genotyping increased the total number of antigen typing results available from 110 980 to >1 200 000. Dense donor typing allowed identification of 2 to 6 times more compatible donors to serve 3146 patients with multiple RBC alloantibodies, providing at least 1 match for 176 individuals for whom previously no blood could be found among the same donors. This genotyping technology is already being used to type thousands of donors taking part in national genotyping studies. Extraction of dense antigen-typing data from these cohorts provides blood supply organizations with the opportunity to implement a policy of genomics-based precision matching of blood.

Development of a recombinant anti-Vel immunoglobulin M to identify Vel-negative donors.

BACKGROUND: Alloimmunization against the high-frequency Vel blood group antigen may result in transfusion reactions or hemolytic disease of fetus and newborn. Patients with anti-Vel alloantibodies require Vel-negative blood but Vel-negative individuals are rare (1:4000). Identification of Vel-negative donors ensures availability of Vel-negative blood; however, accurate Vel blood group typing is difficult due to variable Vel antigen expression and limited availability of anti-Vel typing sera. We report the production of a recombinant anti-Vel that also identifies weak Vel expression. STUDY DESIGN AND METHODS: A recombinant anti-Vel monoclonal antibody was produced by cloning the variable regions from an anti-Vel-specific B cell isolated from an alloimmunized patient into a vector harboring the constant regions of immunoglobulin (Ig)G1-kappa or IgM-kappa. Antibody Vel specificity was tested by reactivity to SMIM1-transfected HEK293T cells and by testing various red blood cells (RBCs) of donors with normal, weak, or no Vel expression. High-throughput donor screening applicability was tested using an automated blood group analyzer. RESULTS: A Vel-specific IgM class antibody was produced. The antibody was able to distinguish between Vel-negative and very weak Vel antigen-expressing RBCs by direct agglutination and in high-throughput settings using a fully automated blood group analyzer and performed better than currently used human anti-Vel sera. High-throughput screening of 13,288 blood donations identified three new Vel-negative donors. CONCLUSION: We generated a directly agglutinating recombinant anti-Vel IgM, M3F5S-IgM, functional in manual, automated agglutination assays and flow cytometry settings. This IgM anti-Vel will improve diagnostics by facilitating the identification of Vel-negative blood donors.

Validation of the NucliSens Extractor combined with the AmpliScreen HIV version 1.5 and HCV version 2.0 test for application in NAT minipool screening.

BACKGROUND: Routine HCV NAT minipool screening (48 donations) of all blood donations was implemented in July 1999 and was combined with HIV NAT in November 2000. This report describes the validation of the NAT methods and the results of quality control testing. STUDY DESIGN AND METHODS: Nucleic acid was extracted from 2-mL plasma samples by using an automated silica-based extraction method (NucliSens Extractor, Organon Teknika). Eluates were tested with RT-PCR (AmpliScreen HIV-1 version 1.5 and AmpliScreen HCV version 2.0 test, Roche Diagnostic Systems). HIV-1 and HCV RNA reference panels and run controls (PeliCheck and PeliSpy, respectively, Sanquin-CLB) and human plasma minipools were used for NAT validation. RESULTS: The 95-percent detection limit (and 95% CI) for HIV-1 RNA genotype B, HIV-1 RNA genotype E, and HCV RNA genotype 1 was 32 (19-76), 30 (17-72), and 21 (13-44) genome equivalents (geq) per mL, respectively. During initial validation, 2332 samples for HIV-1 RNA and 2644 samples for HCV RNA were analyzed, with 13 (0.56%) and 12 (0.45%) invalid test results, respectively. Thereafter, over 19,600 samples (minipools and run controls) were analyzed during the first 11 months of routine screening. Invalid test results for HIV-1 RNA and HCV RNA were found in 1.1 and 1.07 percent of the samples tested, respectively. HIV-1 RNA minipool testing resulted in 27 (0.16%) initial false-positive results and 3 (0.02%) confirmed positive results. HCV RNA minipool testing resulted in four (0.02%) initial false-positive results and five (0.02%) confirmed positive results. CONCLUSION: Routine HIV and HCV NAT minipool screening using the NucliSens Extractor, AmpliScreen HIV-1 version 1.5, and AmpliScreen HCV version 2.0 meets the sensitivity criteria set by the regulatory bodies and provides sufficient specificity and robustness for timely release of blood donations.