Characterization of tubal and decidual leukocyte populations in ectopic pregnancy: evidence that endometrial granulated lymphocytes are absent from the tubal implantation site

Abstract

Objective: To compare and quantify leukocyte populations at the tubal implantation site, in the tubal mucosa away from the implantation site and in the intrauterine decidua in women who have had an ectopic tubal pregnancy with leukocyte populations in the decidualized endometrium in women who have had a normal intrauterine pregnancy.

Design: Retrospective immunohistochemical study.

Setting: Department of Pathology, University of Newcastle, Royal Victoria Infirmary, Newcastle upon Tyne, Tyne and Wear, United Kingdom.

Patient(s): Paraffin-embedded tissue blocks from 30 women who had had an ectopic pregnancy (EP) and control tissue blocks from 19 women who had undergone elective first trimester pregnancy termination.

Intervention(s): None.

Main outcome measure(s): Quantitative analysis of defined leukocyte subpopulations in the fallopian tube (at the implantation site and in the tubal mucosa away from the implantation site) and intrauterine decidua.

Result(s): Endometrial granulated lymphocytes were absent from both the tubal mucosa away from the implantation site and the tubal implantation site. T lymphocytes and macrophages formed the predominant leukocyte subpopulations in both tubal areas. In the intrauterine decidua from women who had had an EP, endometrial granulated lymphocytes were the most abundant leukocyte population and macrophages and T cells formed the second and third major leukocyte subpopulations, respectively. No differences were detected in the number or proportion of these decidual leukocytes in women who had had a normal pregnancy vs. in those who had had an EP.

Conclusion(s): The absence of endometrial granulated lymphocytes from the tubal implantation site suggests that the local presence of the cells is not essential for implantation and early placental development events.