Bone-marrow origin of endometrial granulocytes in the early human placental bed.

A large number of cells in the first trimester human placenta have been shown to express leucocyte-common antigen by the use of a monoclonal antibody in an immunoperoxidase technique. The distribution of endometrial granulocytes in the decidua of early pregnancy indicates that a large proportion of these cells bear the leucocyte-common antigen and are thus bone-marrow derived.