Objective: To study changes in the expression rate of PIBF by peripheral lymphocytes in healthy pregnant women after administration of mifepristone for non-surgical termination of pregnancy at 5-8 wks of gestation.
Methods: Patients requesting early social termination of pregnancy, in a 3-month period, were included. A first venous blood sample was taken before oral administration of 600 mg of mifepristone (day 0). A second venous blood sample was taken 2 days later. PIBF on lymphocytes was determined by immunocytochemistry using a PIBF-specific polyclonal antibody.
Results: Termination of pregnancy was successful and complete in all cases. In 17 out of 21 patients, the percentage of PIBF positive lymphocytes decreased after anti-progesterone administration. The percentage of PIBF-expressing lymphocytes significantly decreased from 52.8%+/-21.6% (day 0) to 39.8%+/-18.2% by day 2 (p=0.001).
Conclusions: These data suggest a strong relationship between early termination of pregnancy induced with mifepristone and disturbances of progesterone-mediated immunosuppression.