Detection of weak D antigen in the population of potential blood recipients

Background
The strongest immunogen of the Rh system is the D antigen. It is found in several variants and categories, which makes it difficult to determine the correct RhD (Rh+) or RhD negative (Rh-) phenotype. Although only some of the varieties and types of this antigen are of clinical significance, it is important to determine the normal Rh phenotype in recipients and donors. The aim of this study was to determine the frequency of weak D antigen in a population of potential recipients.

Material and methods
The study group consisted of selected blood recipients in whom weak expression of the D antigen or its antibody was detected. In order to estimate the expression of antigen D, the blood was analyzed in the laboratory of the Regional Center of Blood Donation and Blood Treatment in Lublin. Blood from 220 potential recipients (149 women and 71 men) were used in the conducted research. The clinical material from the Laboratory of Transfusion Serology at the Provincial Specialist Hospital in Biała Podlaska was also used.

Results
The presence of a weak D was confirmed in 21 recipients. 4 cases of weak D were confirmed among recipients of blood transplant, while 17 cases among those who did not have blood transfusions. There were significant differences in the occurrence of the weak D in relation to the transfusion in both women (χ² = 18.34 df = 2, p = 0.0001) and men (χ² = 17.25).

Conclusions
The correct determination of the RhD+ or RhD- phenotype is important for pregnant women who should be subjected to immunoprophylaxis of maternal-fetal conflict when a weak D is detected. In order to avoid post-transfusion complications among recipients, it is necessary to choose serologically and phenotypically crossed-matched blood components.