INTRODUCTION: Local immune modulation has been shown to be of considerable importance for successful pregnancy. We have previously detected the secretion of IFN-γ, IL-4 and IL-10 in human decidua from early normal pregnancy. The aim of this study was to investigate the cell types in decidua, as well as in peripheral blood, responsible for cytokine secretion.
METHODS: Decidual tissue and peripheral blood was collected from 20 healthy women undergoing surgical abortion during first trimester pregnancy. Monocytes/macrophages and NK cells were obtained by magnetic cell separation and the cytokine secretion was detected by a sensitive enzyme-linked immunosorbent spot-forming cell (ELISPOT) assay.
RESULTS: Decidual and peripheral monocytes/ macrophages and NK cells spontaneously secrete IFN-γ, IL-4 and IL-10. The number of IL-10 secreting cells was significantly higher among decidual macrophages compared with decidual non-monocytic cells and blood monocytes/macrophages. These differences were not seen for IFN-γ or IL-4. Our results indicate that macrophages subserve important suppressive functions in the pregnant uterus.