Molecular genotyping in transfusion medicine.

“Blood-Matching Goes Genetic,” a recent News Focus article in Science (1 ), illustrates the growing awareness of the impact of the genomics revolution on transfusion medicine and its potential to transform the way blood is selected for transfusion. Antibody-based technology has been the basis for blood group typing since the discovery of the ABO blood groups by Landsteiner and colleagues. With the availability of single-nucleotide polymorphism (SNP) genotyping, the blood bank is poised to become one of the primary laboratory disciplines to benefit from the PCRtechnology revolution. DNA-testing methods are applicable to transfusion medicine because the genes encoding blood group antigens and the genetic polymorphisms associated with the antigens are known. Similar to many disease markers, most of the antigens in blood groups result from SNPs inherited in a straightforward Mendelian manner. SNPs account for much of human genome diversity, and the ability to link SNPs to disease or disease risk, and even to individual variation in drug responses, makes SNP profiling a technology likely to contribute to fulfilling the promise of personalized medicine. The appreciation of this potential has fueled the development of high-throughput SNP-genotyping platforms, which are currently being applied in the prediction of blood group antigens (2 ). The use of such platforms enables rapid, cost-effective screening for multiple clinically significant blood groups in a single assay. The field of transfusion medicine can now consider individualized transfusion treatment, i.e., matching donors with patients at multiple blood group loci in addition to the ABO and RhD systems. This approach holds promise for reducing, and potentially eliminating, alloimmunization. Expanded Typing