FIGURE 1

Immunophenotypes of representative chorioamniotic mesodermal cells. (a) The chorioamniotic mesodermal cells near the zone of altered morphology (ZAM) show frequent labeling of CD163, CD14, desmin, and procollagen. Decidual macrophages (arrows), negative to desmin, are in stark contrast. Insets show immunoreactivity for the markers in the same fetal membranes apart from the ZAM. ae, amnion epithelium; am, amnionic mesoderm; cm, chorionic mesoderm; ct, chorionic trophoblasts; de, decidua. (b) Chorionic mesodermal cells showing coexpression of CD163 and type I procollagen on double immunohistochemical staining (brown: CD163-DAB, blue: type I procollagen-Vector blue). (c) Meconium-containing macrophages strongly positive for CD163. Those cells show weak and variable immunoreactivity to desmin. CISH using DYZ1 probe shows distinct nuclear hybridization signals in the chorioamniotic mesodermal cells of ZAM (arrows) indicating their fetal origin. (d) Immunofluorescence staining shows CD68 (blue; Alexa Fluor 633) and SMA (red; Alexa Fluor 568) double-positive cells in the chorioamniotic mesoderm. Nuclei of the cells were stained green (Sytox green). (e) Scattered mesodermal cells are double positive for HLA-DR (blue; Alexa Fluor 633) and SMA (red; Alexa Fluor 568).