Evaluating the TaqMan Jr a -Genotyping Method for Rapidly Predicting the Presence of Anti-Jr a Antibodies

The Jr antigen is a high-prevalence red blood cell (RBC) antigen. Reports on cases of fatal hemolytic disease of the fetus and newborn and acute hemolytic transfusion reactions suggest that antibodies against Jr (anti-Jr ) have potential clinical significance. Identifying anti-Jr is challenging owing to a lack of commercially available antisera. We developed an alternative approach to rapidly predict the presence of anti-Jr using the TaqMan single-nucleotide polymorphism (SNP)-genotyping method. Residual peripheral blood samples from 10 patients suspected of having the anti-Jr were collected. Two samples with confirmed Jr(a-) RBCs and anti-Jr were used to validate the TaqMan genotyping assay by comparing the genotyping results with direct sequencing. The accuracy of the assay in predicting the presence of anti-Jr was verified through crossmatching with in-house Jr(a-) O+ RBCs. The TaqMan-genotyping method was validated with two Jr(a-) RBC- and anti-Jr -confirmed samples that showed concordant Jr genotyping and direct sequencing results. Jr genotyping for the remaining samples and crossmatching the serum samples with inhouse Jr(a-) O+ RBCs showed consistent results. We validated a rapid, simple, accurate, and cost-effective method for predicting the presence of anti-Jr using a TaqMan-based SNP-genotyping assay. Implementing this method in routine practice in clinical laboratories will assist in solving difficult problems regarding alloantibodies to high-prevalence RBC antigens and ultimately aid in providing safe and timely transfusions and proper patient care.