Hormonal control of the secretory immune system of the human uterine cervix.

A quantitative immunohistochemical study of IgA-containing plasma cells in the human uterine cervix has shown that the number of such cells increases during the late secretory phase of the menstrual cycle but decreases in the early secretory phase of the cycle, in pregnancy, in cystic glandular hyperplasia of the endometrium and after the menopause. These results are interpreted as indicating that progesterone causes an increased plasma cell localisation in the cervix whilst oestrogens cause a decrease: it is suggested that this reflects hormonal control of a receptor mechanism and that this receptor can also be blocked by high levels of LH or hCG. The number of cervical epithelial cells containing secretory component (SC) is increased in the late secretory phase of the menstrual cycle, in users of contraceptive pills and in pregnancy. It is suggested that progesterone acts to increase the intra-epithelial content of SC and that no other hormonal factor need be involved.