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.
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.
S
S
Ponnusamy
N
N
Mohammed
S S Y
SS
Ho
H M
HM
Zhang
Y H
YH
Chan
Y W
YW
Ng
L L
LL
Su
A P
AP
Mahyuddin
A
A
Venkat
J
J
Chan
M
M
Rauff
A
A
Biswas
M
M
Choolani
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