INTERCELLULAR-ADHESION MOLECULE-1 (ICAM-1) AND HLA-DR ANTIGENS ARE EXPRESSED ON ENDOVASCULAR CYTOTROPHOBLASTS IN ABNORMAL PREGNANCIES

PROBLEM: We asked if the lack of normal trophoblastic invasion of spir al arteries in the basal plate of abnormal pregnancies was associated with the expression of HLA-DR antigens and intercellular adhesion mole cules (ICAM-1) on endovascular cytotrophoblasts. METHOD: The basal pla tes of placentae from 15 normal and 55 abnormal pregnancies, including preeclampsia, small-for-gestational age infants, and mothers with his tory of secondary recurrent spontaneous abortion, were studied immunoc ytochemically by using monoclonal antibodies to HLA-DR and ICAM-1. Spi ral and uteroplacental arteries were identified by using a triple anti body technique with antibodies to cytokeratin, alpha-smooth muscle act in, and von Willebrand factor to detect cytotrophoblasts, arterial smo oth muscle cells, and endothelium, respectively. RESULTS: Placentae wi th normal placentation showed the presence of uteroplacental arteries that contained endovascular cytotrophoblasts that were negative for HL A-DR and ICAM-1 antigens. Placentae from abnormal pregnancies showed t he presence of spiral arteries without trophoblastic invasion and uter oplacental arteries that were surrounded by numerous macrophages and T lymphocytes. Endovascular cytotrophoblasts in uteroplacental arteries of placentae from abnormal pregnancies reacted with antibodies to HLA -DR and ICAM-1 antigens. CONCLUSION: Placentae from normal pregnancies show uteroplacental arteries that contain endovascular cytotrophoblas ts that do not react with antibodies to ICAM-1 and HLA-DR antigens, an d placentae from abnormal pregnancies with uteroplacental arteries tha t are associated with arteries that do not show physiological changes contain endovascular cytotrophoblasts that react with antibodies to IC AM-1 and HLA-DR antigens. Normal uteroplacental arteries were found to be not surrounded by round cell infiltrates, but uteroplacental arter ies associated with arteries that lack physiological changes were surr ounded by round cell infiltrates, indicating that round cell infiltrat es and endovascular cytotrophoblasts which react with antibodies to IC AM-1 and HLA-DR antigens are associated with abnormal pregnancies. The se findings suggest that the cellular infiltrates are associated with endovascular cytotrophoblasts that react with ICAM-1 and HLA-DR antige ns.