Objective: Our aim was to develop a new technique, which we have termed fetal cell recycling, that combines the 2 powerful methods of fluorescence in situ hybridization and polymerase chain reaction to maximize the genetic information available from a small number of fetal nucleated erythrocytes obtained noninvasively from the blood of pregnant women.
Study design: Blood samples were obtained from 4 Rh-negative women after elective termination of pregnancy at 7 to 17 weeks' gestation. Fetal nucleated erythrocytes were separated by flow sorting with antibody to the gamma chain of fetal hemoglobin. Fluorescence in situ hybridization with chromosome-specific probes was used to diagnose fetal gender. After fluorescence in situ hybridization analysis the fetal nucleated erythrocytes were recycled by a micromanipulation technique and deoxyribonucleic acid diagnosis was performed with polymerase chain reaction amplification of the RhD gene.
Results: Among the 4 case patients we detected a total of 101 fetal nucleated erythrocytes. All targeted cells were successfully retrieved with a micromanipulator. In each case we successfully performed both fluorescence in situ hybridization and polymerase chain reaction analysis. The predicted fetal gender and Rh status corresponded to the results obtained from fetal tissue.
Conclusions: Fetal cell recycling combines the powers of highly sensitive molecular methods to maximize the genetic information available from a single fetal cell. This technique will permit noninvasive diagnosis of recessively inherited single-gene disorders.