KANTER, M., GUL, A., MERAL, I., Koc, A., ILHAN, M. and ERDOGAN, E. Morphological Quantitative Changes in the Number of Lymphocytes, Macrophages and Plasma Cells in the Uterus and Lymph Nodes of Rats Exposed to the Systemic Administration of BCG. Tohoku J. Exp. Med., 2003, 199 (4), 219-228 - This study was designed to investigate the effect of systemic administration of BCG on the morphological quantitative changes in the number of lymphocytes, macrophages and plasma cells in the uterus and lymph nodes of rats. Thirty female virgin Wistar Albino rats, aging 6 months and weighing between 200-250 g, were assigned to the two experimental groups; BCG treated and controls (n = 15). BCG group received 0.1 ml BCG in tail skin and control group received 0.1 ml saline at the same place. Two weeks after injections, rats in both groups were anesthesized with a high dose of ether and decapitated. Uterus and ileocecal lymph nodes were processed to determine alpha napthyl acid esterase (ANAE)-positive T lymphocytes and macrophages. The plasma cells were stained with the methyl green-pyronin method. It was found that the numbers of T lymphocytes, macrophages and plasma cells in the uterus and the ileocecal lymph nodes of BCG treated group significantly increased indicating the presence of an immune response to the systemic BCG administration. It was concluded that the systemic administration of BCG increases humoral and cellular immunity in endometrium, myometrium and regional lymph nodes. The immune deficiency system plays an important role in the pathogenesis of endometriosis. Therefore, the endometriosis might be prevented by using periodical administration of BCG. However, further experimental and clinical studies associated with these issue are required.