Leucocyte populations in ectopic tubal pregnancy.

Leucocytes at the ectopic implantation site in 10 cases of early tubal pregnancy were characterised with a series of monoclonal antibodies using an indirect immunoperoxidase technique on cryostat sections. Most were HLA-DR positive macrophages, and there were a small number of mature T lymphocytes (UCHT1 and Dako-T1 positive cells). These results were compared with those reported in normal first trimester intrauterine pregnancies, and the contributions of the various leucocyte types to successful implantation at both the ectopic and intrauterine sites were assessed.