Disha Parchure1, Manisha Madkaikar2, Swati Kulkarni1. 1. Department of Transfusion Medicine, ICMR-National Institute of Immunohaematology, Mumbai, India. 2. Department of Pediatric Immunology and Leukocyte Biology, ICMR-National Institute of Immunohaematology, Mumbai, India.
Abstract
BACKGROUND: The discovery of the cell-free foetal DNA (cffDNA) circulating in the maternal plasma enabled prediction of foetal RHD thus eliminating the risks associated with invasive procedures. Non-invasive foetal RHD genotyping has now become the standard approach in developed countries for management of alloimmunised women and is also used for targeted antenatal prophylaxis in non-alloimmunised women. MATERIALS AND METHODS: cffDNA was extracted from the plasma of 217 RhD negative pregnant women at a gestational age of 10-34 weeks. The foetal RHD genotype was determined by real-time polymerase chain reaction (real-time PCR) amplification of exons 4, 5 and 10 in duplicates. After an initial 54 samples, foetal typing was carried out with RHD exons 5 and 10 for the remaining samples. CCR5, SRY and RASSF1A genes were used as controls. Results were compared with cord blood serological typing at birth. RESULTS: Out of the 217 women, 193 were non-immunised and 24 were alloimmunised. A conclusive diagnosis was obtained in 203 samples. Diagnosis was inconclusive in 14 samples; of these, foetal RHD genotype could be resolved in six samples after maternal and paternal RHD genotyping. A 100% diagnostic accuracy, sensitivity and specificity were demonstrated in 209 women who had had a conclusive result. When the inconclusive samples were included, diagnostic accuracy and sensitivity were more than 95% and specificity was 78.95%. DISCUSSION: Anti-D is still the leading cause of haemolytic disease of the foetus and the newborn in India. There is, therefore, a need to establish and develop an algorithm for antenatal RhD negative women in India. The positive results of non-invasive foetal RHD genotyping, from the start of the 10th week of gestation using two RHD exons giving 100% diagnostic accuracy, show promise for routine diagnostic use to the benefit of the antenatal RhD negative Indian population.
BACKGROUND: The discovery of the cell-free foetal DNA (cffDNA) circulating in the maternal plasma enabled prediction of foetal RHD thus eliminating the risks associated with invasive procedures. Non-invasive foetal RHD genotyping has now become the standard approach in developed countries for management of alloimmunised women and is also used for targeted antenatal prophylaxis in non-alloimmunised women. MATERIALS AND METHODS: cffDNA was extracted from the plasma of 217 RhD negative pregnant women at a gestational age of 10-34 weeks. The foetal RHD genotype was determined by real-time polymerase chain reaction (real-time PCR) amplification of exons 4, 5 and 10 in duplicates. After an initial 54 samples, foetal typing was carried out with RHD exons 5 and 10 for the remaining samples. CCR5, SRY and RASSF1A genes were used as controls. Results were compared with cord blood serological typing at birth. RESULTS: Out of the 217 women, 193 were non-immunised and 24 were alloimmunised. A conclusive diagnosis was obtained in 203 samples. Diagnosis was inconclusive in 14 samples; of these, foetal RHD genotype could be resolved in six samples after maternal and paternal RHD genotyping. A 100% diagnostic accuracy, sensitivity and specificity were demonstrated in 209 women who had had a conclusive result. When the inconclusive samples were included, diagnostic accuracy and sensitivity were more than 95% and specificity was 78.95%. DISCUSSION: Anti-D is still the leading cause of haemolytic disease of the foetus and the newborn in India. There is, therefore, a need to establish and develop an algorithm for antenatal RhD negative women in India. The positive results of non-invasive foetal RHD genotyping, from the start of the 10th week of gestation using two RHD exons giving 100% diagnostic accuracy, show promise for routine diagnostic use to the benefit of the antenatal RhD negative Indian population.
Authors: Mia P S Jensen; Merete B Damkjaer; Frederik B Clausen; Haivin A Ali; Kristine J Hare; Morten H Dziegiel; Finn S Jørgensen Journal: Acta Obstet Gynecol Scand Date: 2019-04-01 Impact factor: 3.636
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Authors: C Rouillac-Le Sciellour; V Sérazin; Y Brossard; O Oudin; C Le Van Kim; Y Colin; Y Guidicelli; M Menu; J-P Cartron Journal: Transfus Clin Biol Date: 2008-03-28 Impact factor: 1.406