Foreign fetal cells persist in the maternal circulation

Objective

To determine whether allogenic fetal cells resulting from donor egg pregnancies persist in maternal circulation.

Design

Nested polymerase chain reaction (PCR) amplification of the DYS14 sequence, a region of the Y chromosome, from DNA purified from peripheral blood cells.

Setting

Academic medical center.

Patient(s)

Healthy 18–60-year-old women who have had donor egg pregnancies resulting in a male offspring (n = 11) or, as a control, female offspring (n = 8), at least 1 year previously and without any other source for male cells in their peripheral blood or a healthy male.

Intervention(s)

None.

Main Outcome Measure(s)

Detection of DYS14 sequence by nested PCR.

Result(s)

DYS14 was detected in 5/11 (45%) of women who had donor egg pregnancies resulting in a male offspring, but in 0/8 (0) of women who had donor egg pregnancies resulting in a female offspring. The longest interval between delivery of a male offspring and detection of the DYS14 gene was 9 years.

Conclusion(s)

Unmatched, allogenic fetal cells from donor egg pregnancies are able to persist in the circulation of healthy women for at least 9 years after delivery. This implies a novel mechanism by which immunologic detection is avoided by these cells and may impact on how they may be used for regenerative and transplant medicine.

Key Words: Fetal microchimerism, stem cells, regenerative medicine, donor eggs