Lymphocyte subsets in the endometrium of patients with endometriosis throughout the menstrual cycle

PROBLEM: Comparison and characterisation of different lymphocyte subsets in the endometrium of endometriosis patients and in healthy women on every day of the menstrual cycle with special emphasis on the CD4:CD8 ratio in the endometrium. METHOD: Immunohistochemical staining of 253 endometrial biopsies of infertile women with and without endometriosis with Anti-Leu4 (CD3), Anti-Leu3a (CD4), Anti-Leu2a (CD8), Anti-Leu7 and Anti-Human-B-cell (CD22) using the immune peroxidase reaction. Identification and counting of positive lymphocyte were performed on cryostat sections. RESULTS: Endometrial lymphocyte subsets show equal quantity and distribution in endometriosis patients and in the control group. After a peak in the early proliferative phase the absolute number of T lymphocytes decreases while a predominance of T-suppressor/cytotoxic T lymphocytes (CD8) compared to T-helper/inducer lymphocytes (CD4) occurs towards the end of the menstrual cycle. CONCLUSION: Endometrium as the potential parent epithelia of endometriosis lesions seems not to be altered in its lymphatic cell content compared to healthy women. Furthermore, endometrium is clearly characterised as part of the mucosa associated lymphatic tissue (MALT). T lymphocytes show specific quantitative changes due to different phases of the menstrual cycle.