Prenatal non-invasive foetal RHD genotyping: diagnostic accuracy of a test as a guide for appropriate administration of antenatal anti-D immunoprophylaxis.

Autor:	Manfroi S; Immunohaematology and Transfusion Medicine Service Metropolitan Area of Bologna, 'S. Orsola-Malpighi' Polyclinic, Bologna, Italy., Calisesi C; Immunohaematology and Transfusion Medicine Service, 'Ospedale degli Infermi', Rimini, Italy., Fagiani P; Immunohaematology and Transfusion Medicine Service Metropolitan Area of Bologna, Imola Hospital, Imola, Italy., Gabriele A; Immunohaematology and Transfusion Medicine Service Metropolitan Area of Bologna, 'Maggiore' Hospital, Bologna, Italy., Lodi G; Immunohaematology and Transfusion Medicine Service, 'S. Anna' Hospital, Ferrara, Italy., Nucci S; Immunohaematology and Transfusion Medicine Service, 'Ospedale degli Infermi', Rimini, Italy., Pelliconi S; Immunohaematology and Transfusion Medicine Service Metropolitan Area of Bologna, 'S. Orsola-Malpighi' Polyclinic, Bologna, Italy., Righini L; Immunohaematology and Transfusion Medicine Service Metropolitan Area of Bologna, 'S. Orsola-Malpighi' Polyclinic, Bologna, Italy., Randi V; Regional Blood Centre of Emilia-Romagna, 'Maggiore' Hospital, Bologna, Italy.
Jazyk:	angličtina
Zdroj:	Blood transfusion = Trasfusione del sangue [Blood Transfus] 2018 Nov; Vol. 16 (6), pp. 514-524. Date of Electronic Publication: 2018 Apr 09.
DOI:	10.2450/2018.0270-17
Abstrakt:	Background: Foetal RHD genotyping can be predicted by real-time polymerase chain reaction (qPCR) using cell-free foetal DNA extracted from maternal plasma. The object of this study was to determine the diagnostic accuracy and feasibility of non-invasive RHD foetal genotyping, using a commercial multiple-exon assay, as a guide to appropriate administration of targeted antenatal immunoprophylaxis. Material and Methods: Cell-free foetal DNA was extracted from plasma of RhD-negative women between 11-30 weeks of pregnancy. The foetal RHD genotype was determined non-invasively by qPCR amplification of exons 5, 7 and 10 of the RHD gene using the Free DNA Fetal Kit ® RhD. Results were compared with serological RhD cord blood typing at birth. The analysis of diagnostic accuracy was restricted to the period (24-28 +6 weeks) during which foetal genotyping is usually performed for targeted antenatal immunoprophylaxis. Results: RHD foetal genotyping was performed on 367 plasma samples (24-28 +6 weeks). Neonatal RhD phenotype results were available for 284 pregnancies. Foetal RHD status was inconclusive in 9/284 (3.2%) samples, including four cases with RhD maternal variants. Two false-positive results were registered. The sensitivity was 100% and the specificity was 97.5% (95% CI: 94.0-100). The diagnostic accuracy was 99.3% (95% CI: 98.3-100), decreasing to 96.1% (95% CI: 93.9-98.4) when the inconclusive results were included. The negative and positive predictive values were 100% (95% CI: 100-100) and 99.0% (95% CI: 97.6-100), respectively. There was one false-negative result in a sample collected at 18 weeks. After inclusion of samples at early gestational age (<23 +6 week), sensitivity and accuracy were 99.6% (95% CI: 98.7-100) and 95.5% (95% CI: 93.3-97.8), respectively. Discussion: This study demonstrates that foetal RHD detection on maternal plasma using a commercial multiple-exon assay is a reliable and accurate tool to predict foetal RhD phenotype. It can be a safe guide for the appropriate administration of targeted prenatal immunoprophylaxis.
Databáze:	MEDLINE
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