Vaginal microbiome and HPV - interplay or coincidence?

The vaginal microbiome is a dynamic, balanced system of microorganisms, which under normal conditions ensures a balance between the physiological lactobacilli - Lactobacillus species and the pathogenic bacterial flora and enables protection against pathogenic microorganisms. The vaginal microbiome plays a role in the infection and persistence of the HPV virus in the human vagina, as well as in the subsequent development and progression of cervical intraepithelial lesions. Lactic acid produced by lactobacilli acidifies the vaginal environment, strengthens the protective role of H2O2 and bacteriocins and inhibits opportunistic infections and HPV infection. The D-isomer of lactic acid increases the viscosity of cervicovaginal mucus, protects against urogenital infections, and enhances the potential destruction capabilities of HPV virus particles. Growth of strict anaerobes, which are associated with bacterial vaginosis, is relatively often registered in association with cervical dysplasia. When they colonize, they produce enzymes and metabolites that can compromise the barrier and facilitate the entrance of HPV. In women with HPV infection and cervical intraepithelial lesions, Lactobacillus iners dominates often, whose role is still controverse.
A pH value of the vaginal secretion higher than 5 is significantly associated with a 10-20% increased risk for HPV positivity among women before menopause, i.e. in the reproductive period. The HPV E5 protein, which is responsible for viral transformation, is particularly sensitive to low pH, which is one of the possible mechanisms. There are also contradictory results regarding the correlation of bacterial vaginosis with incidence, prevalence and persistence of HPV infection, as well as with the development of cervical intraepithelial lesions, which is explained by the lack of objective diagnostic tests for bacterial vaginosis or subjective scoring systems, as well as by the heterogeneity of the bacterial vaginosis itself. vaginosis. The results from our ongoing study for vaginal microbiome and HPV status will be presented.
Although numerous studies show some correlation between HPV infection and cervical changes, more research is needed to prove this sophisticated relationship between the host, the microbiota and carcinogenesis. Of course, if any connection is proven, the clinical significance would be enormous and would open up the potential for therapeutic strategies that would include the manipulation of the vaginal microbiome with the stimulation of those that have a protective role for health.