Distribution of lymphocyte subsets in ectopic and eutopic endometrium during endometriosis

Objective: The purpose of this study was to assess the population of CD45RO+, CD4+, and CD8+T-lymphocytes in eutopic and ectopic endometrium in women with endometriosis, and to explore the role and activity of immunocytes in endometriosis, and their relevance to immunotherapy. Methods: Monoclonal antibodies against CD45RO, CD4, and CD8 were used for immunohistochemical staining to indicate positive cells in eutopic and ectopic endometrial tissues of women with endometriosis. The distribution and density of the different lymphocyte populations was compared with normal endometrium from healthy controls. Results: While lymphocytes staining positive for CD45RO, CD4, CD8 were present in the proliferative and secretory endometrium of tissues from both the endometriosis and control groups, there was a higher percentage of positive lymphocytes in tissues from the endometriosis group (P 0.05), and the percentage of positive lymphocytes in tissues from the ectopic endometriosis group was greater than from the eutopic endometriosis group (P 0.05). CD4 positive cells were also slightly increased in the ectopic and eutopic endometriosis groups compared with the control group, but this difference was not statistically significant (P 0.05). The ratio of CD4+/CD8+ lymphocytes in the eutopic and ectopic endometrium was lower than in the control group (P 0.05); however, there were no significant differences in the percentage of CD4 positive cells or the ratio of CD4+/CD8+ cells between the eutopic and ectopic endometrial tissue samples (P 0.05). There was also a slight (but not significant) increase in the percentage of CD45RO+, CD4+, and CD8+ cells during the transition from the proliferative phase to the secretory phase in eutopic endometrium. There was also no significant difference in CD45RO, CD4, and CD8 expression in ectopic endometrium and normal control endometrium during the transition from the proliferative phase to the secretory phase. Finally, there were no significant differences in the number of CD45RO+, CD4+, or CD8+ cells in two cases of stage I/II and III/IV disease (P 0.05). Conclusion: The distribution of T-lymphocyte subsets in eutopic and ectopic endometrium are related to the progression of endometriosis, and immunotherapy targeting specific sub-sets of lymphcytes may be useful for the treatment of endometriosis.