Pregnancy as a model of controlled invasion might be attributed to the ratio of CD3/CD8 to CD56

PROBLEM: Pregnancy can be considered as a model of successfully controlled tissue invasion. Cellular mediated immunity appears to regulate the controlled invasion of fetal trophoblast cells. In endometrium cancer, a dysregulation of invasive malignant cells can be observed. Since immuncompetent cells are known to be involved in recognition and rejection of 'non-self' antigens, we investigated the presence and distribution pattern of CD3, CD8, CD56, and CD68 positive cells in decidua from normal and failing pregancies, compared with malignant and benign endometrium. METHOD OF STUDY: Decidual tissue from first trimester normal pregancies (NP; n = 15) and abortion (AB; n = 12), endometrial samples from premenopausal women (NE; n = 8), and endometrioid adenocarcinoma (EA; n = 8) were examined by immunohistochemistry using monoclonal antibody against large spectrum cytokeratin, and against the receptors CD3, CD8, CD56 and CD68, respectively. RESULTS: In NP, we observed 32.5% CD3, 44.7% CD56, and 22.9% CD68 (+) cells. In AB, we found 36.9% CD3, 45.3% CD56, and 17.8% CD68 (+) cells. The differences in ratio between normal pregnancy and abortion were not statistically significant. In NE, we counted 39.5% CD3, 30.2% CD56 and 30.2% CD68 (+) cells. In EA, we observed 47.9% CD3, 12.4% CD56 and 39.7% CD68 (+) cells. The decrease of CD56 positive cells in endometrioid adenocarcinoma was statistically significant. Interestingly, we found 4.1% of cells positive for CD8 in NP, 4.9% in AB, 22.7% in NE, and 48.2% in EA. CONCLUSIONS: The increase of CD8 cells in NE, and particularely in EA, and decrease of CD56 cells, compared with NP or BE, suggests an interaction between CD8 cells and CD56 cells. Studying different pathological situations in the uterus, such as malignancies or ectopic pregnancies, might help us to understand the mechanisms involved in the maintenance of pregnancy.