The effectiveness of KEL and RHCE fetal genotype assessment in alloimmunized women by minisequencing

Czech version

Authors: V. Durdová ¹; J. Böhmová ²; T. Kratochvílová ¹; R. Vodička ²; I. Holusková ³; K. Langová ⁴; M. Lubušký ¹
Authors‘ workplace: Porodnicko-gynekologická klinika LF UP a FN, Olomouc, přednosta prof. MUDr. R. Pilka, Ph. D. ¹; Ústav lékařské genetiky LF UP a FN, Olomouc, přednosta prof. MUDr. M. Procházka, Ph. D. ²; Transfuzní oddělení FN, Olomouc, vedoucí oddělení MUDr. D. Galuszková, Ph. D., MBA ³; Ústav lékařské biofyziky LF UP, Olomouc, přednostka prof. RNDr. H. Kolářová, CSc. ⁴
Published in: Ceska Gynekol 2020; 85(3): 164-173
Category: Original Article

Overview

Objective: To evaluate the effectiveness of the fetal KEL and RHCE genotype assessment in alloimmunized pregnant women by minisequencing.

Design: Prospective cohort study.

Setting: Obstetrics and Gynecology Clinic of the Faculty of Medicine UP and the University Hospital Olomouc; Institute of Medical Genetics of the Faculty of Medicine UP and the University Hospital Olomouc; Transfusion Department of the University Hospital Olomouc; Institute of Biophysics of the Faculty of Medicine UP Olomouc.

Subject and method: In the years 2001–2019, 366 samples of pregnant women in the first and second trimester were assessed KEL (n = 327) or RHCE (n = 39) genotype from the free fetal DNA circulating in the peripheral blood by minisequencing. The genotype of the fetus was verified from the buccal smear of the newborn.

Results: The KEL genotype was assessed in 327 women (the presence of a variant of the KEL1 alele, which corresponds to the presence of the erythrocyte antigen “K“. The analysis failed in 2 cases (2/327), 16 heterozygote women (KEL1/KEL2) were excluded and in the case of 309 homozygote women (KEL2/KEL2) the fetal KEL genotype was assessed.

In the case of 95.8% of the fetuses (296/309) and 95.5% of the newborns (295/309), the KEL2/KEL2 genotype was assessed. In the case of 4.2 % of the fetuses (13/309) and 4.5% of the newborns (14/309), the KEL1/KEL2 genotype was assessed. The sensitivity was 92.86%. The specificity was 100%.

The RHCE genotype was assessed in 39 women. In the case of 22 women, the presence of a variant of the RHCE gene, which corresponds to the presence of the erythrocyte antigen “C“/“c“, was assessed. 5 heterozygote women (C/c) were excluded. In the case of 11 homozygote women (C/C), the RHCE genotype was assessed. In the case of 64% (7/11) of the fetuses and newborns, the C/c genotype was assessed, in the case of 36% (4/11) the C/C genotype was assessed.

In the case of 6 homozygote women (c/c), the RHCE genotype was assessed.

In the case of 67% (4/6) of the fetuses and newborns, the C/c genotype was assessed, in the case of 33% (2/6) the c/c genotype was assessed. The sensitivity and specificity were 100%.

In the case of 17 women, the presence of the variant of the RHCE gene, which corresponds to the presence of the erythrocyte antigen “E“/“e“, was assessed. 1 heterozygote woman (E/e) was excluded. In the case of 16 homozygote women (e/e), the RHCE genotype was assessed. In the case of 75% (12/16) of the fetuses and newborns, the e/e genotype was assessed, in the case of 25% (4/16) the E/e genotype was assessed. The sensitivity and specificity were 100%.

Conclusion: The minisequencing method using the capillary electrophoresis enabled a reliable detection of the fetal KEL and RHCE genotype from the peripheral blood of pregnant women.

Keywords:

pregnancy – alloimmunization – cell free DNA – KEL and RHCE genotype

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