In vivo model to determine fetal-cell enrichment efficiency of novel noninvasive prenatal diagnosis methods.
OBJECTIVE
To develop an in vivo model to determine fetal-cell enrichment efficiency of novel noninvasive prenatal diagnosis methods.


METHODS
Efficiency of our three-step enrichment protocol was determined in vitro before fetal nucleated red blood cells (FNRBCs) were enriched from first-trimester maternal blood samples collected from the same patients pre- and postsurgical termination of pregnancy (TOP) (n = 10). FNRBCs enriched were identified using embryonic epsilon-globin immunocytochemistry and chromosomal fluorescence in situ hybridization.


RESULTS
We recovered 37% of spiked FNRBCs (95% confidence interval (CI) 28.5-45.6; n = 8) in in vitro experiments. We show a consistent threefold increase in the number of epsilon + FNRBCs in maternal blood obtained immediately post-TOP (p = 0.005). A mathematical relationship was derived: observed number of pretermination primitive FNRBCs = 0.6 + 0.31 (coefficient between pretermination/post-termination primitive FNRBCs, 95% CI 0.12-0.49; p = 0.005) x observed number of post-termination primitive FNRBCs (R2 = 0.65).


CONCLUSIONS
Our data demonstrate that maternal blood obtained immediately post-TOP would be a good in vivo model to determine the enrichment efficiency of novel protocols and methods for noninvasive prenatal diagnosis.
Ponnusamy
S
S
Diagnostic Biomarker Discovery Laboratory, Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Mohammed
N
N
Ho
S S Y
SS
Zhang
H M
HM
Chan
Y H
YH
Ng
Y W
YW
Su
L L
LL
Mahyuddin
A P
AP
Venkat
A
A
Chan
J
J
Rauff
M
M
Biswas
A
A
Choolani
M
M
D004900:Erythroblasts; D005260:Female; D005312:Fetal Blood; D033042:Fetal Research; D005331:Fetomaternal Transfusion; D005333:Fetus; D005914:Globins; D006801:Humans; D008431:Maternal-Fetal Exchange; D008954:Models, Biological; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis / Q000379:methods*
D005914:Globins