Disturbed feto-maternal cell traffic in preeclampsia.

OBJECTIVE: To investigate whether the transfer of fetal blood cells to the maternal circulation is perturbed in pregnancies affected by preeclampsia. METHODS: Fetal erythroblasts were isolated from eight women with clinically diagnosed preeclampsia (blood pressure values of at least 140/90 mmHg and associated proteinuria) and an equal number of matched corresponding controls. All patients in both groups were pregnant with male singleton fetuses. The presence of fetal cells was evaluated histologically and by fluorescence in situ hybridization for X and Y chromosomes. RESULTS: The number of fetal cells was higher in preeclamptic patients than in controls, with respect to both nucleated red blood cells (median per 200 cells 38 versus 7; P < .001) and the proportion of these cells that were of fetal origin (median per 2000 cells 9 versus 2; P = .001). CONCLUSION: These results suggest that the trafficking of fetal cells into the maternal periphery is disturbed in patients with preeclampsia. Because it is unlikely that such an altered flow of cells is restricted to the erythroblasts examined in this study, these findings also may lead to interesting new concepts regarding the development of preeclampsia and possibly the associated syndrome of hemolysis, elevated liver enzymes, and low platelets.

[Prenatal diagnosis]. / Pränatale Diagnostik.

A growing number of methods for the in-utero diagnosis of fetal disease became available during recent decades, mainly due to rapid advances in ultrasound technology and laboratory methods. Exclusion of fetal aneuploidy in pregnancies of women beyond 34 years is still by far the most common reason for an invasive procedure event at a time when the number of diagnosable inborn errors of metabolism and monogenetic disorders is increasing rapidly. Great efforts have been made to improve the poor predictive value of maternal age as an indicator for an increased risk for fetal aneuploidy. Maternal serum screening using various parameters [e.g. AFP, hCG, uE3] has been found effective in identifying the majority of pregnancies with Down syndrome in the second trimester. Current research goals are the optimal choice of markers and the introduction of maternal serum screening in the first trimester of pregnancy. Ultrasound is another suitable tool to identify pregnancies at high risk for aneuploidy at least in the hands of experienced operators. The diagnostic use of fetal cells in the maternal circulation is presently investigated in a large collaborative trial. Second trimester amniocentesis still is the most widely applied invasive technique in pregnancies with maternal age related risks for fetal aneuploidy. Safety and diagnostic accuracy are well established and amniotic fluid can easily be shipped. Without major changes in conventional sampling and laboratory techniques the procedure can be performed at 13 weeks of gestation and later. The safety and efficacy of first-trimester amniocentesis has still to be established in larger series. First-trimester chorionic villus sampling is a well-established alternative to amniocentesis with comparable procedure-related risks. It is the method of first choice in pregnancies at high risk for aneuploidy, inborn errors of metabolism and monogenic disorders, since uncultured villi can be used for a rapid diagnosis. Placental biopsy should also be considered in the second and third trimester of pregnancy for these indications whenever time is a critical issue. Fetal blood obtained by ultrasound-guided cordocentesis has successfully been used for the diagnosis of fetal infection and is at the same time another good source of cells for rapid karyotyping. Other invasive procedures such as fetal skin or liver biopsies for electron microscopy or specific metabolic tests are restricted to the relatively rare instances of diseases where DNA diagnosis is currently not available or uninformative. Providing information on the different alternatives in an individual situation is one of the critical issues in pregnancy care today.

Hae III restriction of DNA from three cases with nonfluorescent Y chromosomes (45XO/46XYnf).

Hae III restriction patterns are reported in three cases with normal-sized but nonfluorescent Y chromosomes (XO/XYnf mosaics). The 3.4- and 2.1-kb fragment classes of reiterated Y chromosomal DNA were not present in the three cases. Mechanisms leading to these findings are discussed.

Fetal cells in maternal blood.

Fetal cells have been successfully detected in maternal blood in all three trimesters of gestation in a substantial proportion of normal pregnancies. Various enrichment techniques have been developed for fetal trophoblast cells, leucocytes and nucleated red blood cells. Nucleated red blood cells are considered to be best suited for noninvasive prenatal diagnosis. Fluorescence in-situ hybridization detected the first cases of fetal trisomy in maternal blood after enrichment of fetal nucleated red blood cells. Despite recent encouraging results, accurate and reproducible diagnoses of fetal anomalies by polymerase chain reaction or fluorescence in-situ hybridization require further optimization of enrichment devices and detection protocols.

Enrichment of fetal nucleated red blood cells from the maternal circulation for prenatal diagnosis: experiences with triple density gradient and MACS based on more than 600 cases.

OBJECTIVE: We wanted to obtain statistically relevant data about the efficiency of our method for the isolation of fetal nucleated red blood cells (NRBCs) from the maternal circulation. METHODS: More than 600 samples were investigated using a triple density gradient followed by magnetic separation of anti-CD71-labeled cells, and yields and purities of recovered NRBCs were determined. RESULTS: The enrichment effectivity as well as the morphological condition of cells was reproducibly good, if blood samples were enriched within 48 h after sampling. The efficacy was independent of various methodological parameters and our technique was superior to other magnetic cell-sorting techniques. Mean yields and purities of NRBCs increased with increasing gestational age, ranging from 100 to 1,000 cells per 40-ml blood sample and from 0.1 to 1%, respectively, from the 6th week of gestation to term. In pregnancies with preeclampsia NRBCs were increased by a factor of 10. CONCLUSION: Our enrichment technique proved to be optimized with respect to various methodological parameters, which were compared in the present study, and it is efficient and reproducible for the enrichment of NRBCs from the maternal circulation in all three gestational trimesters.