INTERLEUKIN-8 IN THE HUMAN ENDOMETRIUM

We have previously shown that interleukin-8 (IL-8), a cytokine with ne utrophil chemotactic/activating and T cell chemotactic activity, is pr oduced by human endometrial stromal and glandular cells in culture. Th e present study investigated the temporal and spatial expression of IL -8 messenger ribonucleic acid (mRNA) and protein in the human endometr ium. Endometrial tissue (n = 52) was obtained fi om human uteri after hysterectomy conducted for reasons other than endometrial disease or f rom endometrial biopsies. The day of the menstrual cycle was establish ed from women's menstrual history and was confirmed by histology. Half of the tissues (n = 26) were snap-frozen in liquid nitrogen, cellular RNA was extracted, and Northern blots were hybridized with a riboprob e complementary to a specific sequence-of IL-8 mRNA. The remaining tis sues (n = 26) were processed for frozen sections, and immunohistochemi stry was performed using mouse antihuman IL-8 antibody. Comparison of IL-8 mRNA levels throughout the menstrual cycle revealed that late sec retory and early to midproliferative phase IL-8 expression was signifi cantly greater than midcycle expression (P < 0.02). Analysis of the IL -8 immunohistochemistry revealed that IL-8 protein is found in the sur face epithelium and glands throughout the menstrual cycle. There was n o detectable immunoreactive IL-8 in the stromal cells. We conclude tha t IL-8 is produced in the human endometrium in vivo, and the variation s of IL-8 mRNA throughout the menstrual cycle suggest that sex hormone s may regulate its gene expression. We speculate that IL-8 may modulat e the timely recruitment of neutrophils and lymphocytes into the endom etrium.