Immunohistochemical localization of interferons in human placental tissues in normal, ectopic, and molar pregnancy.

Interferon (IFN)alpha, beta, and gamma have been localized in normal and pathological human pregnancy using both polyclonal and monoclonal antibodies in immunohistochemical techniques. IFN alpha was localized to fetal chorionic villous syncytiotrophoblast throughout normal pregnancy, as well as to extravillous trophoblast in the placental bed and chorion lave. Maternal decidual leukocytes, as well as fetal Hofbauer cells in the villous mesenchyme, also contained IFN alpha, IFN gamma was detected in villous syncytiotrophoblast, while anti-IFN beta showed only patchy weak reactivity with syncytiotrophoblast. Reaction patterns on ectopic pregnancy tissues were similar to those in early intrauterine pregnancy. In molar pregnancy, reactivity for IFN alpha, beta, and gamma was observed in syncytiotrophoblast. Along with their potential anti-viral effects, placental interferons could play a role in local immunomodulation or in regulation of embryonic cell proliferation and differentiation.