Problem: Our objective in this study was to correlate immunosuppressive properties of follicular fluid (FF) and media conditioned by zygotes and early embryos with the occurrence of conception in an in vitro fertilization (IVF) program.
Method of study: Fifty-seven IVF patients were studied. Donor lymphocytes were incubated with mitogens and FF from mature oocytes or conditioned media from zygotes and early embryos. Proliferation was assessed by radioactive thymidine incorporation. Proliferation Index (PI) was the ratio between radioactive labeling of lymphocytes incubated in the presence and absence of a mitogen.
Results: The FFs and media conditioned by zygotes from conception cycles had higher immunosuppressive activity than those from non-conception cycles.
Conclusions: Immunosuppressive activity present in FF and media conditioned by zygotes may be a major determinant of conception in IVF, and may serve as a marker for embryo quality.