Using the method of molecular genetic typing to determine variants of the weak antigen D in the diagnosis of Rh-affiliation

Background. Determination of Rh-affiliation is mandatory for donors and recipients, surgical patients, pregnant women, etc. There are variants of the D antigen that are difficult to identify by serological methods, for example, a weak D antigen.

Aim. Determination of Rh-affiliation using genotyping in difficult cases, when the use of serological methods does not allow obtaining a reliable result.

Material and methods. We studied blood samples from donors (n=18), pregnant women (n=17) and patients with hematological diseases (n=15): 22 men and 28 women, median age 36 years (25 to 54 years). Serologically, antigen D was determined by gel technology in ID-cards and in an indirect antiglobulin test with anti-D-IgG reagent. Weak D antigen variants were diagnosed and phenotype determined using polymerase chain reaction with allele-specific primers. For significance of differences in the frequency of types of weak antigen D, a nonparametric statistical method using a two-tailed Fisher's exact test was used. Differences were considered statistically significant at p <0.05.

Results. The use of genotyping made it possible to detect the presence of a weak antigen D in 41 samples. Its specificity was represented by the following types: 1; 1.1; 2; 3. Other types of weak antigen D [4; 4.0; 4.1; 4.2 (DAR); 5; 11; 14; 15; 17] were absent. The study of the phenotype of erythrocyte antigens of the Rhesus system using genotyping revealed the predominance of the Ccee phenotype in people with a weak D antigen. Significant differences in the frequency of types of this antigen were revealed.

Conclusion. The use of molecular genetic typing made it possible to determine the types of the weak antigen D and to accurately determine the Rh-affiliation of the subjects.