Scripta Medica (Jan 2017)
First results in genotyping for blood donors of the Republic of Srpska with serological weak D antigen
Abstract
Introduction: The Rh system is very complex, polymorphous and the most significant for clinical practice, along with the ABO blood group system. The D antigen is the most important antigen in the Rh system and the most immunogenic one, following the ABO antigens. The D antigen, which consists of a mosaic of epitopes, is determined in all the blood donors and patients. Most people are either RhD positive or RhD negative, but there is a certain number of people who have a variation of the D antigen, which are called weak D, partial D and DEL phenotypes. Aim of the Study: The objective is to use molecular methods to determine whether blood donors in the Republic of Srpska (with whom a serological weak D antigen has been detected) really have the weak D antigen, partial D, a combination of these two variants or if their D antigen is normally present, but the used anti-D serum tests did not have the avidity needed to prove the presence of this antigen in blood donors. Patients and Methods: Blood samples were used from regular blood donors, who had been determined as persons with a weaker D antigen (based on the agglutination strength) using serological techniques, the test tube method, the microplate method and the gel method. To determine the blood groups and red blood cell/erythrocyte antigen typing, the following methods were applied: a) test tube method or agglutination in an aqueous environment, b) gel method, c) microplate method and d) molecular determination of blood groups. Results: Blood group samples were collected from April 2016 to February 2017 in the Institute for Transfusion Medicine of Republika Srpska. During this period, blood was collected from 8153 voluntary donors. It was serologically proved that 40 donors (0.49%) had the weak D antigen. All results where the weak D antigen was determined serologically were confirmed by molecular testing. 23 respondents were proved to have weak D type 3 (0.28%), while 17 had weak D type 1 (0.20%). Conclusion: The results from the first molecular testing of our population is in accordance with the results of frequency of weak D antigen in the populations of other European countries, though it did show a small advantage of weak D type 3 over weak D type 1.
