ABO GENOTYPING IN ITALIAN BLOOD-DONORS

Background. Traditional ABO blood group serology is based on the immun oreactivity of antisera with the carbohydrate A, B and H antigens. Pro gress in the molecular biology of the ABO system has recognized the mo lecular basis of the red cell (RBC) antigens and has provided a geneti c model for ABO polymorphism at the molecular level. Recently, this ge netic model was tested in a large number of individuals. Materials and Methods. In this study we applied DNA analysis to determine the frequ ency of ABO genotypes in a group of blood donors for whom the ABO type was known. Two hundred and fifty healthy Italian blood donors were an alyzed using polymerase chain reaction (PCR) to amplify two different regions of genomic DNA, each of which contained a different nucleotide polymorphism. The amplified product was digested with 4 restriction e nzymes that revealed differences among A, B and 0 individuals. To anal yze the genes at polymorphic sites 261 and 703 we used the restriction enzymes BstE II and Kpn I, and Hpa II and Alu I and compared the PCR determined genotypes to serologically determined phenotypes. Results a nti Conclusions. The results were consistent for all unrelated individ uals; however, 2 of 100 individuals with the 0 phenotype carried one a llele that differed from the proposed genetic model. This novel 0 alle le, termed 0(2) by Yamamoto et al., was found in our series with a fre quency of 1%. The blood group ABO genotype of 250 healthy Italian bloo d donors was: 13 AA/A0(2), 37 A0(1), 11 BE, 39 B0(1), 50 AB, 98 0(1)0( 1) and 2 0(1)0(2). This method should be applicable not only in forens ic medicine but also in immunohematology when serology fails.