Impact of the menstrual cycle and ethinyl estradiol/etonogestrel contraceptive vaginal ring on granulysin and other mucosal immune mediators

Abstract

Changes in sex hormones during the menstrual cycle and contraceptive vaginal ring (CVR) use influence immunity within the female genital tract, but the magnitude of these effects and their anatomical location are unclear. In a prospective study, 29 women were assessed at three-time points: follicular phase, luteal phase, and one month after initiation of the ethinyl estradiol/etonogestrel CVR (NuvaRing®, Merck). We performed microarrays on endocervical cytobrushes and measured immune mediators in cervicovaginal fluid, adjusting for bacterial vaginosis and the presence of blood. We compared these results to public gene expression data from the fallopian tubes, endometrium, endo- and ectocervix, and vagina. Immune-related gene expression in the endocervix and immune mediators in cervicovaginal fluid increased during CVR use versus both menstrual phases, and in the follicular versus luteal phase. The antimicrobial protein granulysin was high during CVR use, intermediate in the follicular phase, and nearly absent from the luteal phase. Re-analysis of public gene expression data confirmed increased immune-related gene expression in the endocervix during the follicular phase. However, in the fallopian tube, endometrium, and vagina, the follicular phase showed immunosuppression. Immune-related genes in the cervicovaginal tract were highest during CVR use, intermediate in the follicular phase, and lowest in the luteal phase. Granulysin is a potential biomarker of menstrual phase: Frequently detected in follicular samples, but rare in luteal. Lastly, immunological differences between the follicular and luteal phases vary throughout the female genital tract.