Identification of leucocytes within the human chorion laeve

Occasional macrophages and granulocytes have been detected within the cytotrophoblast layer of the chorion laeve in normal term placentae. It is clearly important to identify these leucocytes in studies of antigen expression by trophoblastic populations within the amniochorion. The relevance of these observations to any immunocompetent interactions between maternal and fetal cells through the chorion laeve remains to be established.