Interferon gamma expression during human pregnancy and in association with labour.

In this study, the expression of the type 1 cytokine, interferon gamma (IFNgamma) during human gestation and in association with labour was assessed. Immunoreactive (ir) IFNgamma concentrations (ng/ml) were quantified in maternal plasma (n = 136) and amniotic fluid (n = 68). In addition, irlFNgamma content (pg/mg protein) was determined in term gestational tissues (placenta, amnion and choriodecidua, n = 39). In peripheral plasma, irlFNgamma was detected in 34% of all samples assayed. Where detected, the concentration averaged 0.19 +/- 0.03 ng IFNgamma/ml plasma (mean +/- SEM). During pregnancy, irlFNgamma concentrations in maternal plasma declined significantly (p < 0.05). irlFNgamma was identified in all gestational tissues examined and content increased significantly with labour status (p < 0.01). irlFNgamma was not detectable in amniotic fluid (assay sensitivity = 0.02 ng/ml) at any stage of pregnancy. The data obtained are consistent with the hypothesis that, during pregnancy, cell-mediated immunity is suppressed. At term and in association with labour and delivery, lower plasma IFNgamma concentrations and high tissue content may indicate a contributing role for IFNgamma in parturition.