Erythrocyte genotyping for transfusion-dependent patients at the Azienda Universitaria Policlinico of Naples

Background and objectives: Although minor erythrocyte antigens are not considered clinically significant in sporadic transfusions, they may be relevant for multi-transfusion patients. When serological assay is not conceivable, molecular genotyping allows predicting the red blood cell phenotype, extending the typing until minor blood groups. The aim of this study was to evaluate the utility of blood group genotyping and compare the molecular typing of erythrocyte antigens with the established serological methods.

Materials and methods: We selected 225 blood donors and 50 transfusion-dependent patients at the Division of Immunohematology of the Second University of Naples. Blood samples were analyzed with NEO Immucor automated system and genotyped for 38 red blood cell antigens and phenotypic variants with the kit HEA BeadChip™. The comparative study was conducted for RhCE and Kell antigens whose typing is available with both methods.

Results: We observed a good correlation between serological and molecular methods for donors that were concordant for 99.5% (224/225) and discordant for 0.5% (1/225). Patients resulted concordant only for 46.0% (23/50) and discordant for 54.0% (27/50); discrepancies were 46.0% (23/50) and 8.0% (4/50) for RhCE and Kell systems respectively. Through molecular genotyping we also identified polymorphisms in RhCE, Kell, Duffy, Colton, Lutheran and Scianna loci in donors and patients.

Conclusions: Blood group genotyping is particularly useful for poly-transfused patients. Molecular analysis confirms and extends serological test data and then allows us to obtain a better match. This molecular assay can be used in the future to prevent alloimmunization in transfusion-dependent patients.