ENDOMETRIAL LEUKOCYTES - EXPRESSION OF STEROID-HORMONE RECEPTORS

Background-Stromal leucocyte populations in human endometrium comprise T cells, macrophages, and phenotypically unusual endometrial granulat ed lymphocytes. Their proportions vary during the menstrual cycle and, in particular, endometrial granulated lymphocytes increase in number in the late secretory phase. The stimulus responsible for these cyclic al changes is unknown but it is likely that the steroid hormones oestr ogen and progesterone play a role. Aims-To define further the expressi on of steroid hormone receptors by leucocytes in non-pregnant and preg nant human endometrium. Methods-Frozen and paraffin wax embedded secti ons of endometrium from non-pregnant women and early pregnancy decidua were labelled using single and double immunohistochemical techniques with monoclonal antibodies directed against oestrogen and progesterone receptors and various leucocyte subpopulations. Results-Despite the p rominence of CD56 positive endometrial granulated lymphocytes in late secretory phase endometrium and early pregnancy decidua, double immuno histochemical labelling showed no evidence of expression of either pro gesterone or oestrogen receptors by these cells or other endometrial l eucocyte populations. Conclusions-Rather than acting directly, steroid hormones are likely to influence endometrial leucocyte populations in directly via products of endometrial stromal or epithelial cells that express steroid hormone receptors.