Detection of fetal cells in intrauterine lavage samples collected in the first trimester of pregnancy.
OBJECTIVE
The aim of the present study was first to evaluate the presence of fetal cells in transcervical cell (TCC) samples collected by intrauterine lavage in the first trimester of pregnancy, and then to compare different methods for the detection of these cells.


METHODS
TCC samples were collected by intrauterine lavage before termination of pregnancy (TOP) from 81 pregnant women between 7 and 12 weeks of gestation. Samples of placental tissue were collected from each patient at TOP, whereas maternal peripheral blood samples were obtained in 57 cases. DNA extracted from 81 lavage and the corresponding placental samples was amplified by a polymerase chain reaction (PCR) assay using primers for SRY and HUMARA genes. All 81 lavage samples were also analysed by fluorescent in situ hybridisation (FISH) using direct-labelled probes for X chromosome alpha-satellite (DXZ1, Xp11.1-q11.1) and Y chromosome alpha-satellite (DYZ3, Yp11.1-q11.1) regions. In 57 cases, a quantitative fluorescent (QF) PCR assay, involving the use of two small tandem repeat (STR) markers (D21S11, D21S14.11) specific to chromosome 21 was employed to analyse DNA extracted from placental tissue, lavage and maternal blood samples.


RESULTS
PCR analysis revealed that 40/81 placental samples were from male pregnancies. Correct sexing was achieved with the PCR technique in 30/40 (75%) lavage samples retrieved from pregnant women with male conceptuses and in all 41 (100%) samples collected from pregnancies with female fetuses. With the FISH analysis, nuclei bearing X and Y signals were observed in 32/40 cases (80%) from known male pregnancies, the rate of fetal cells ranging between 2% and 95%, whereas nuclei showing X and Y signals were not detected in any of the 41 lavage samples from known female pregnancies. Paternal peaks were present in 30/57 (52.6%) lavage samples tested by QF-PCR.


CONCLUSIONS
The results suggest that fetal cells can be found, at a significant rate, in a very high proportion of intrauterine lavage samples. Therefore, this sampling technique can be regarded as a promising tool towards minimally invasive prenatal diagnosis. The FISH and PCR methods showed a similar efficiency in detecting fetal cells.
Cioni
Riccardo
R
Department of Gynecology, Perinatology and Human Reproduction, University of Florence, Florence, Italy. rcioni@yahoo.it
Bussani
Cecilia
C
Scarselli
Benedetta
B
Barciulli
Francesco
F
Bucciantini
Sandra
S
Simi
Paolo
P
Fogli
Antonella
A
Scarselli
Gianfranco
G
D000328:Adult; D015342:DNA Probes; D005260:Female; D005333:Fetus / Q000166:cytology*; D005865:Gestational Age; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012732:Sex Determination Analysis; D020080:Tandem Repeat Sequences; D007507:Therapeutic Irrigation; D014599:Uterus / Q000166:cytology*; D014960:X Chromosome; D014998:Y Chromosome
D015342:DNA Probes