FETAL NUCLEATED ERYTHROCYTE RETRIEVAL FROM MATERNAL BLOOD

Haruo Takabayashi, Soryu Kuwabara, Toshihiko Ukita*, Tatsuhiro Igarashi**

Dept. of Obst. & Gyn., Kanazawa Medical Univeristy, Ishikawa, Japan.*Ukita Hosp., **Hakuikan Hosp.

Several attempts have been made to retrieve fetal nucleated cells including nucleated erytrocytes(NRBCs), leukocytes and trophoblasts in maternal blood. Until now the evidence that fetal cells can be retrieved from maternal blood has been inconclusive.

However, we have recently developed a method for non-invasive fetal DNA diagnosis from maternal blood. Peripheral blood granulocytes including NRBCs were isolated by a discontinuous density gradient method using Percoll (Pharmasia). NRBCs have been success-fully found and retrieved using a micromanipulator under a microscope in 33 out of 39 maternal samples from 8-23 weeks of gestation. To determine whether the origin of NRBCs is maternal or fetal, NRBCs were analysed by the polymerase chain reaction(PCR) amplifi-cation to determine the presence of Y chromosome-specific repeat sequence in mothers carrying male fetuses.

This new technique opens up fetal DNA diagnosis from maternal blood during the first trimester of pregnancy to the whole population because there is no risk to the fetus or the mother.