Lactobacillus-Depleted Vaginal Microbiota in Pregnant Women Living With HIV-1 Infection Are Associated With Increased Local Inflammation and Preterm Birth

Background Pregnant women living with HIV-1 infection (PWLWH) have an elevated risk of preterm birth (PTB) unknown aetiology, which remains after successful suppression HIV. Women at high for HIV a common bacterial profile has been associated poor outcomes. We set out to explore factors gestational age delivery PWLWH in UK population. Methods Prospective study (n = 53) whom the vaginal microbiota and cervicovaginal cytokine milieu were assessed using metataxonomics multiplexed immunoassays, respectively. Cross-sectional characterisation compared 22 uninfected pregnant (HUPW) similar second trimester timepoint. Within relationships between composition, inflammatory response, explored. Findings There was rate PTB among (12%). In more diverse than HUPW (Inverse Simpson Index, p 0.0004 Species Observed, 0.009). had lower prevalence L. crispatus dominant group (VMB I, 15 vs 54%) higher iners III, 36 9% VMB IIIB, 5%) mixed anaerobes IV, 21 0%). Across third trimesters PWLWH, III/IIIB IV increased local inflammation [cervicovaginal fluid (CVF) concentrations upper quartile]. High diversity anaerobic abundance also CVF pro-inflammatory cytokines, most notably IL-1β. Interpretation is association inflammation, dysbiosis PWLWH. Understanding potential antiretroviral therapies influence this cascade will be important improve outcomes