Leukocyte populations, hormone receptors and apoptosis in eutopic and ectopic first trimester human pregnancies

The implantation of trophoblast cells at extrauterine sites still results in decidualization. The objective of the present study was to compare decidualization at eutopic and ectopic implantation sites. Tissues from women undergoing elective termination of uterine pregnancy and from women with ectopic pregnancy were used to detect the presence of cells important for the maintenance of pregnancy, such as BCL-2+, CD56+, CD3+, CD8+ and CD68+ cells, and the presence of oestrogen (ER) and progesterone receptors (PR) by immunohistochemistry. In-situ detection of fragmented DNA was performed to identify apoptotic cells. The percentage of CD3+ cells among all immunocompetent cells in the tubal epithelium was 46.6% (39.9% of CD3+ were also CD8+); the other 53.4% were CD68+ cells. CD56+ cells were undetectable in ectopic decidua at the feto-maternal interface in ectopic tissue. In uterine decidua, we found 29.9% CD3+ cells (2.2% of CD3+ were CD8+), 51.6% CD56+ cells and 18.5% CD68+ cells. The ratio of BCL2+ to CD3+ cells in ectopic pregnancy was 0.41. In uterine pregnancy, the ratio of BCL-2 to CD3 was 0.44 and 0.39 for CD56. Tissues from both ectopic and uterine pregnancies were positive for PR. Fewer apoptotic cell bodies were present in ectopic pregnancy. The use of tissue obtained from ectopic pregnancy may become an excellent model to identify the mechanism of trophoblast invasion in eutopic pregnancies.