Cytokine secretion patterns of NK cells and macrophages in early human pregnancy decidua and blood: Implications for suppressor macrophages in decidua

Problem: Local immune modulation has been shown to be of considerable importance for the maintenance of successful pregnancy. We have previously reported the secretion of interferon-γ (IFN-γ), interleukin-4 (IL-4) and IL-10 in human decidua from early normal pregnancy. The aim of this study was to investigate the cellular source of cytokine secretion in the decidua, and compare this to secretion patterns in peripheral blood. Method of study: Decidual tissue and peripheral blood was collected from 20 women undergoing surgical abortion during first trimester pregnancy. Monocytes/macrophages and NK cells were enriched by immunomagnetic cell separation and cytokine secretion was detected by enzyme-linked immunosorbent spot-forming cell 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 in decidual macrophages compared with decidual non-monocytic cells as well as compared with blood monocytes/macrophages. These differences were not seen for IFN-γ or IL-4. Conclusions: Our results indicate that decidual macrophages subserve important suppressive functions in the pregnant uterus.