Kratochvílová T., Holusková I., Durdová V., Strašilová P., Ľubušký M. Klinický význam neinvazivního stanovení RHD a RHCE genotypu plodu v managementu těhotenství s rizikem rozvoje hemolytické nemoci plodu a novorozence. Postgrad. Med. 2016, 18 (4), s. 362-369. (The clinical significance of the non-invasive fetal RHD and RHCE genotype assessment in the management of pregnancies at risk of hemolytic disease of the fetus and newborn)
ABSTRACT
In the Czech Republic, all pregnant women in their 1st trimester undergo the red blood cell antibody screening. The clinically significant alloantibody anti-D is diagnosed in about 0.5% of women (500 women a year in the Czech Republic). However, the fetuses are at risk of hemolytic disease only if the complementary antigen is present on their erythrocytes. This is the case of about 60% of them (300 fetuses a year) in contrast to 40% of them (200 fetuses a year) lacking the complementary antigen and thus not at risk of Hemolytic Disease of the Fetus and Newborn (HDFN). The presence of the complementary antigen can be assessed noninvasively by RHD genotyping from cell-free fetal DNA circulating in the peripheral blood of pregnant women.The clinically significant alloantibody anti-C is diagnosed in about 0.1% of women (100 women a year in the Czech Republic). However, about 56% of fetuses (56 fetuses a year) lack the complementary antigen and thus are not at risk of HDFN. Also, the clinically significant alloantibody anti-c is diagnosed in about 0.1 % of women (100 women a year in the Czech Republic). However, about 44% of fetuses (44 fetuses a year) lack the complementary antigen and thus are not at risk of HDFN. The presence of the complementary antigen can be assessed noninvasively by RHCE genotyping from cell-free fetal DNA circulating in the peripheral blood of pregnant women. The clinically significant alloantibody anti-E is diagnosed with the highest frequency, in about 0.6% of women (600 women a year in the Czech Republic), but it can be produced without the stimulus of the red blood cell antigen. Such antibody is not an alloantibody and it is not clear if it can cause the development of HDFN. In addition, about 84% fetuses (504 fetuses a year) lack the complementary antigen and thus are not at risk of HDFN. The presence of the complementary antigen can be assessed noninvasively by RHCE genotyping from cell-free fetal DNA circulating in the peripheral blood of pregnant women. In contrast, the clinically significant alloantibody anti-e is diagnosed in about 0.02% of women (20 women a year in the Czech Republic) and the complementary antigen is present in most of the fetuses, about 84% of them (17 fetuses a year). Thus, the assessment of the complementary antigen by the noninvasive RHCE genotyping has no clinical importance in the management of pregnancies at risk of HDFN.