The distribution and possible function of gamma interferon-immunoreactive cells in normal endometrium and myometrium.

T-lymphocytes are present in normal endometrium, where they may have a role in the control of glandular maturation. T-cell activity could be related to the local secretion of cytokines such as gamma interferon, which has an anti-proliferative effect on endometrial epithelial cells in vitro. We have examined gamma interferon immunoreactivity and T-cell distribution in 24 normal pre-menopausal uteri. Endometrial appearances were representative of all stages of the menstrual cycle. Most cells in the lymphoid aggregates in the stratum basalis were stained by T-cell and gamma interferon antisera. T-lymphocytes were also scattered in glandular epithelium and throughout the stroma of basal and functional layers; immunoreactivity for gamma interferon was less consistent in these cells. There was no alteration in the intensity or distribution of gamma interferon staining in different phases of the menstrual cycle. Endometrial granulocytes (K-cells) present mainly in the late secretory endometria were not reactive with the gamma interferon antiserum. In addition to endometrial staining, T-cells were distributed in all areas of the myometrium in most uteri, and many myometrial lymphocytes were gamma interferon positive. These results support a role for gamma interferon in endometrial physiology, possibly as an inhibitor of epithelial proliferation.