Obravnava nosečnic glede na tip RhD
Treatment of pregnant women by RhD type

slovenian

2019

volume 88, issue 11/12

partial D   variants D   weak D

Slovensko zdravniško društvo
(Obvezni izvod spletne publikacije)

An accurate determination of RhD (D) antigen (Ag) is important for pregnant women, transfusion recipients and blood donors. The decision to receive the pre- and postnatal prophylaxis with anti-D immunoglobulin (RhIG) is based on the D-type. Individuals can be classified as D-posi- tive (D-pos) or D-negative (D-neg) based on the determination of Ag D but there are numerous other versions of Ag D as well (variants D, D-var). Allele variants of the RHD (D) gene can encode different forms of protein D. They are divided into weak, partial and D el . Ag D are determined on the basis of serological techniques. If in doubt, we use the molecular-biological methods for determining the D gene. The definitive definition of D-var is given on the basis of the molecular - -biological methods . From the peripheral venous blood samples taken from pregnant women, we roughly determi- ned Ag D on plates (the Seraclone anti-D reagent) and on gel cards (the DiaClon ABO / D + Re verse Grouping test system (monoclonal antibodies) (Bio-Rad, Germany), with which we do not detect D category VI blood group). For 49 pregnant women we performed extended serological tests of D blood group (commercial ID-Partial RhD Typing Set (Bio-Rad, Germany)). We procee - ded with molecular-biological methods: DNA isolation (utilisation of the BioRobot EZ1 and the commercial set EZ1 DNA Blood 350 %l Kit (Qiagen, Germany)), determination of the genotype D with the PCR-SSP method (commercial RBC-Ready Gene CDE, RBC -Ready Gene D weak and RBC-Ready Gene D AddOn (Inno-Train; Germany)), amplification (Veriti apparatus (Apllied Bio - Systems, USA)), product separation (electrophoretic system (BioRad, USA) on agarose gel (Si- gma, Germany). Our results showed that weak D forms represented 41 cases (83.7 %) and partial forms 8 cases (16.3 %) of all D-var. The most common D-var in pregnant women was weak D type 1 with 17 ca- ses (34.7 %), followed by weak D type 3 with 13 cases (26.5 %) and weak D type 2 with 10 cases (20.4 %). The most common partial D form was D category VII with 5 cases (10.2 %). Pregnant women and transfusion recipients who are carriers of weak D types 1, 2 or 3 can be safely treated as D-pos, while carriers of all other D-var can be treated as D-neg. Blood donors with D-var are treated as D-pos. By means of this algorithm, approximately 172 unnecessary RhIG applications can be prevented annually and adequate supplies of D-neg erythrocyte blood com- ponents can be maintained.

24.08.2020