Enhancement of mononuclear cell oxidative burst by early post-transfer sera from human patients after unsuccessful embryo transfer

Abstract

Early pregnancy sera were earlier shown to modulate T lymphocyte rosetting with sheep erythrocytes. We set out to investigate whether early pregnancy sera also modulate the state of activation of another immunologically relevant cell type, the monocyte. As an index of monocyte activation, we measured phorbol ester-triggered oxidative burst activity by a highly sensitive chemiluminescence method. Contrary to our expectations, incubation of mononuclear cells with sera taken early after embryo transfer from patients with a successfully developing pregnancy had no effect. Unexpectedly, such sera from patients from a control group of patients in whom no pregnancy developed after embryo transfer caused enhancement of mononuclear cell chemiluminescence. Stimulatory activity of these sera appeared between days 4 and 6 and was maximal between days 7 and 9 post embryo transfer. Whether this phenomenon is causally related to, or represents a consequence of the failure of embryo transfer, can currently not be decided.