Subtle perturbations of genital microflora alter mucosal immunity among low-risk pregnant women

Abstract

Objective Alteration in the vaginal flora has been associated with adverse pregnancy outcomes. The objective of this study was to examine the impact of changes in individual microflora on genital immunity among low-risk pregnant women in early pregnancy. Design Cross-sectional study. Setting Large, tertiary care, academic hospital clinic. Population Low-risk women were enrolled prior to 14 weeks’ gestation. Methods Women were included if they had no medical or previous obstetrical complications, were non-smokers, had no sexually transmitted infections and no intercourse in the last 48 hours. Consenting women underwent speculum examination for collection of vaginal culture and Dacron swabs for cytokine analysis. Semi-quantitative vaginal cultures were performed in a reference laboratory. Main Outcome Measures Concentrations of immune mediators were compared in the presence of various organisms. Concentrations were converted to multiples of the median to standardize the values of each mediator. Regression analyses were performed to control for race. Results We enrolled 47 women. The frequencies of genital microorganisms were: H2O2-producing lactobacilli (70%), Ureaplasma urealyticum (66%), Gardnerella vaginalis (45%), anaerobic non-pigmented Gram-negative rods (ANPGNR, 40%), anaerobic pigmented Gram-negative rods (APGNR, 17%). After adjusting for race and body mass index, interleukin-1β, interferon-γ, tumor necrosis factor-α and granulocyte macrophage-colony stimulating factor were increased in the presence of G. vaginalis, ANPGNR, and APGNR. There was no consistent impact on the other markers of immune activation. Conclusion The presence of individual species impacts genital immunity among low-risk pregnant women. Perturbations in genital immunity could partially explain heterogeneity in adverse pregnancy outcomes.

DoAtopobium vaginae, Megasphaerasp. andLeptotrichiasp. change the local innate immune response and sialidase activity in bacterial vaginosis?

“…Slight changes in the microbial composition of the vaginal flora were already demonstrated to influence the local cytokine production 38. Nevertheless, no trend to increases on the levels of cytokine was found in relation to the participation of A vaginae , Megasphaera sp.…”

Interaction Between Lactobacilli, Bacterial Vaginosis-Associated Bacteria, and HIV Type 1 RNA and DNA Genital Shedding in U.S. and Kenyan Women

“…with lower levels of genital HIV-1 RNA. 21 Gardnerella vaginalis has been associated with higher concentrations of vaginal interleukin (IL)-1b 26,27 and Lactobacillus spp. with lower concentrations of IL-8.…”

The vaginal microbiota, human papillomavirus infection and cervical intraepithelial neoplasia: what do we know and where are we going next?

“…There also exists evidence that inflammation plays an important role in dysbiosis-induced cervical disease. Clinical studies have shown that levels of vaginal proinflammatory cytokines are higher in women with dysbiosis [69, 70] which can result in chronic inflammation; a well-known factor in carcinogenesis of numerous tissues in the body [97]. …”