Transient association between semen exposure and biomarkers of genital inflammation in South African women at risk of HIV infection

Abstract

Introduction Semen induces mucosal changes in the female reproductive tract to improve pregnancy outcomes. Since semen‐induced alterations are likely short‐lived and genital inflammation is linked to HIV acquisition in women, we investigated the contribution of recent semen exposure on biomarkers of genital inflammation in women at high HIV risk and the persistence of these associations. Methods We assessed stored genital specimens from 152 HIV‐negative KwaZulu‐Natal women who participated in the CAPRISA 008 trial between November 2012 and October 2014. During the two‐year study period, 651 vaginal specimens were collected biannually (mean five samples per woman). Cervicovaginal lavage (CVL) was screened for prostate‐specific antigen (PSA) by ELISA, whereas Y‐chromosome DNA (YcDNA) detection and quantification were conducted by RT‐PCR, representing semen exposure within 48 hours (PSA+YcDNA+) and semen exposure within three to fifteen days (PSA−YcDNA+). Soluble protein concentrations were measured in CVLs by multiplexed ELISA. T‐cell frequencies were assessed in cytobrushes by flow‐cytometry, and vulvovaginal swabs were used to detect common vaginal microbes by PCR. Linear mixed models adjusting for factors associated with genital inflammation and HIV risk were used to assess the impact of semen exposure on biomarkers of inflammation over multiple visits. Results Here, 19% (125/651) of CVLs were PSA+YcDNA+, 14% (93/651) were PSA−YcDNA+ and 67% (433/651) were PSA−YcDNA−. Semen exposure was associated with how often women saw their partners, the frequency of vaginal sex in the past month, HSV‐2 antibody detection, current gonorrhoea infection and Nugent Score. Both PSA detection (PSA+YcDNA+) and higher cervicovaginal YcDNA concentrations predicted increases in several cytokines, barrier‐related proteins (MMP‐2, TIMP‐1 and TIMP‐4) and activated CD4+CCR5+HLA‐DR+ T cells (β = 0.050; CI 0.001 to 0.098; p = 0.046) and CD4+HLA‐DR+ T cells (β = 0.177; CI 0.016 to 0.339; p = 0.032) respectively. PSA detection was specifically associated with raised pro‐inflammatory cytokines (including IL‐6, TNF‐α, IP‐10 and RANTES), and with the detection of BVAB2 (OR = 1.755; CI 1.116 to 2.760; p = 0.015), P. bivia (OR = 1.886; CI 1.102 to 3.228; p = 0.021) and Gardnerella vaginalis (OR = 1.815; CI 1.093 to 3.015; p = 0.021). Conclusions More recent semen exposure was associated with raised levels of inflammatory biomarkers and the detection of BV‐associated microbes, which declined by three to fifteen days of post‐exposure. Although transient, semen‐induced alterations may have implications for HIV susceptibility in women.

Starting to have sexual intercourse is associated with increases in cervicovaginal immune mediators in young women: a prospective study and meta-analysis

“…[15][16][17][18][19][20][21][22] In addition, BV is associated with recent sexual activity, especially exposure to semen. [23][24][25][26][27] BV is associated with increased CVT IL-1α and IL-1β, which agrees with our finding of higher IL-1α and IL-1β post-first sex. However, BV is also associated with reduced CXCL10, 28 which conflicts with our finding of increased CXCL10 after first sex.…”

“…Numerous studies show that BV is rare prior to first sex, increases after first sex ( Tabrizi et al, 2006 ; Fethers et al, 2012 ; Fethers et al, 2011 ; Fethers et al, 2009 ; Francis et al, 2020 ; Francis et al, 2019 ; Mitchell et al, 2012 ; Thoma et al, 2011a ), is associated with recent sexual activity, and is associated with exposure to semen ( Gajer et al, 2012 ; Ma et al, 2013 ; Jewanraj et al, 2021 ; Mngomezulu et al, 2021 ; Thoma et al, 2011b ). Therefore, vaginal bacteria may play a role in these increased immune mediator levels.…”

“…Exposure to semen has been associated with increases in cervical leukocytes ( Pandya and Cohen, 1985 ; Thompson et al, 1992 ; Sharkey et al, 2012 ) and inflammatory cytokines, especially IL-6 and CXCL10, in most ( Jewanraj et al, 2021 ; Mngomezulu et al, 2021 ; Sharkey et al, 2012 ; Francis et al, 2016 ; Jespers et al, 2017 ; Kyongo et al, 2012 ) but not all studies ( Agnew et al, 2008 ; Nakra et al, 2016 ). In vitro exposure to seminal plasma induces cytokines including IL-1α, IL-6, and CXCL8 in cervical and vaginal epithelial cells ( Sharkey et al, 2007 ) and cervical explants ( Adefuye et al, 2014 ; Denison et al, 1999 ; Introini et al, 2017 ).…”

“…Exposure to semen has been associated with increases in cervical leukocytes [31][32][33] and inflammatory cytokines, especially IL-6 and CXCL10, in most 25,26,[33][34][35][36] but not all studies. 37,38 In vitro exposure to seminal plasma induces cytokines including IL-1α, IL-6, and CXCL8 in cervical and vaginal epithelial cells 39 and cervical explants.…”

Considerations for Choosing Soluble Immune Markers to Determine Safety of Novel Vaginal Products

“…Most CVL and swab collections cannot accurately adjust for dilution factor ( 60 , 63 ), which can vary quite significantly from participant to participant ( 67 ), making the assessment of actual in vivo concentrations and comparison across studies difficult ( 61 , 68 – 70 ). Additional participant-specific factors, such as vaginal pH, mucus, the presence of blood or semen ( 71 , 72 ), or sampling device-specific factors, such as flocked swabs vs. Dacron swabs, or choice of phosphate-buffered saline [pH 7.2] vs. saline [pH 5.5] as a sample diluent have also been shown to impact measurement of cytokine concentrations ( 58 , 63 , 73 ). Inter-laboratory and inter-assay reproducibility of cytokine measurements from cervicovaginal samples is a further concern ( 58 , 74 ).…”