Do fetal extravillous trophoblasts circulate in maternal blood postpartum?

Abstract

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. AbstractIntroduction: Circulating fetal extravillous trophoblasts may offer a superior alternative to cell-free fetal DNA for noninvasive prenatal testing. Cells of fetal origin are a pure source of fetal genome; hence, unlike the cell-free noninvasive prenatal test, the fetal cell-based noninvasive prenatal test is not expected to be affected by maternal DNA. However, circulating fetal cells from previous pregnancies may lead to confounding results. Material and methods:To study whether fetal trophoblast cells persist in maternal circulation postpartum, blood samples were collected from 11 women who had given birth to a boy, with blood sampling at 1-3 days (W0), 4-5 weeks (W4-5), around 8 weeks (W8) and around 12 weeks (W12) postpartum. The existence of fetal extravillous trophoblasts was verified either by X and Y chromosome fluorescence in situ hybridization analysis or by short tandem repeat analysis. To exclude technological bias in isolating fetal cells, blood samples were also collected from 10 pregnant women between a gestational age of 10 and 14 weeks, the optimal time frame for cell-based noninvasive prenatal test sampling. All the samples were processed according to protocols established by ARCEDI Biotech for fetal extravillous trophoblast enrichment and isolation.Results: Fetal extravillous trophoblasts were found in all the 10 samples from pregnant women between a gestational age of 10 and 14 weeks. However, only 4 of 11 blood samples taken from women at 1-3 days postpartum rendered fetal extravillous trophoblasts, and only 2 of 11 samples rendered fetal extravillous trophoblasts at 4 weeks postpartum. Conclusions:In this preliminary dataset on few pregnancies, none of the samples rendered any fetal cells at or after 8 weeks postpartum, showing that cell-based noninvasive prenatal testing based on fetal extravillous trophoblasts is unlikely to be influenced by circulating cells from previous pregnancies. K E Y W O R D S chorionic villi sampling, fetal cells, fetal extravillous trophoblasts, noninvasive prenatal testing, prenatal diagnosis S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section.

Overview and recent developments in cell‐based noninvasive prenatal testing

“…This persistence makes fetal circulating lymphocytes and stem/progenitor cells unsuitable for non‐invasive prenatal testing, as their presence in subsequent pregnancies could confound test results. In contrast, fnRBC and trophoblasts are rapidly cleared from the maternal circulation after delivery, with none detectable ≥8 weeks post‐partum 13 . Primitive erythroblasts from the yolk sac are the first fnRBC to appear at 7‐12 weeks gestation, but disappear after 12w, 14 when definitive erythroblasts, derived from the fetal liver, appear.…”

“…In contrast, fnRBC and trophoblasts are rapidly cleared from the maternal circulation after delivery, with none detectable ≥8 weeks post-partum. 13 Primitive erythroblasts from the yolk sac are the first fnRBC to appear at 7-12 weeks gestation, but disappear after 12w, 14 when definitive erythroblasts, derived from the fetal liver, appear. The trophoblasts that enter the maternal circulation can originate from different trophoblast cell types.…”

Cell‐based non‐invasive prenatal diagnosis in a pregnancy at risk of cystic fibrosis

“…However, other technical issues may explain these findings as the authors used REPLI‐g Single Cell Kit for WGA, which, following manufacturer's protocol, cannot be used for fixed cells 13 . Recent results published by Weymaere et al (and supplemented by experiences from our laboratory) demonstrate that whole genome amplified DNA from a single fetal extravillous trophoblast using PicoPLEX Single Cell WGA kit (Takara Bio Inc.) is sufficient for STR or SNP genotyping to identify fetal origin of isolated candidate cells 14,15 . Overall, the feasibility of cell‐based NIPT relies not only on an efficient technology for enrichment and isolation of the fetal extravillous trophoblasts, but also on the ability to obtain fetal DNA of a quality sufficient for the genetic analysis.…”

Research Progress in Isolation and Enrichment of Fetal Cells from Maternal Blood

“…is persistence makes circulating fetal lymphocytes and granulocytes unsuitable for NIPD, as their presence in subsequent pregnancies may influence test results. In contrast, FNRBC and trophoblast cells were cleared from the maternal circulation rapidly after delivery and were not detected after ≥8 weeks [16]. erefore, at present, trophoblast cells and fetal nucleated red cells are mainly studied as fetal cells in prenatal diagnosis.…”