Preliminary results of fetal Rhc examination in plasma of pregnant women with anti-c

Objectives Anti‐Rhc antibodies may be the reason for the hemolytic disease of the newborn, therefore, noninvasive Rhc determination is important for pregnancy monitoring. For this purpose, we decided to introduce real‐time polymerase chain reaction (PCR) method. Methods Blood from 200 donors, plasma and whole‐blood from 11 Rhc‐negative mothers, as well as blood from fathers and newborns were examined. Rhc sensitivity and specificity were first determined by real‐time PCR using genomic DNA from donors. The same Rhc genotyping method was used for fetal Rhc detection in maternal plasma. To confirm the fetal Rhc‐negative result, plasma was tested with a panel of biallelic insertion/deletion polymorphisms for the presence of fetal DNA. Results The c allele assay showed full specificity. The mean Ct value for one copy of c allele diluted in C‐negative DNA was determined from extrapolating the correlation curve as 39.9. Full concordance was observed between the fetal Rhc genotypes from maternal plasma and the newborn phenotypes. Conclusions Preliminary results show that it is possible to examine fetal c allele of RHCE gene in the plasma of pregnant women with anti‐c by means of a noninvasive method. The diagnostic accuracy of the procedure, however, has yet to be confirmed in a larger group. Copyright © 2008 John Wiley & Sons, Ltd.