The Complex Interplay between Vaginal Microbiota, HPV Infection, and Immunological Microenvironment in Cervical Intraepithelial Neoplasia: A Literature Review

Background: in recent years, many studies were carried out to explore the role of vaginal microbiota in HPV infections and cervical intraepithelial neoplasia (CIN) progression. The aim of this study was to conduct a review of the literature to analyze the interaction between the vaginal microbiota, the CIN, and the immunological response. Methods: we performed a literature search, considering papers published between November 2015 and September 2021. Results: despite significant evidence suggesting a role of vaginal microbiota in the pathogenesis of HPV-related lesions, some studies still struggle to demonstrate this correlation. However, the vaginal microbiota of HPV-positive women shows an increased diversity, combined with a reduced relative abundance of Lactobacillus spp. and a higher pH. In cervical dysplasia progression, a strong association is found with new bacteria, and with the deregulation of pathways and hyperexpression of cytokines leading to chronic inflammation. Conclusions: in HPV progression, there is a strong correlation between potential biomarkers, such as Sneathia and Delftia found in community state types IV and II, and chronic inflammation with cytokine overexpression. Better analysis of these factors could be of use in the prevention of the progression of the disease and, eventually, in new therapeutic strategies.

Automated summary

This study reviewed the interaction between vaginal microbiota, cervical intraepithelial neoplasia (CIN), and the immune response. While some studies struggle to demonstrate the correlation between vaginal microbiota and HPV-related lesions, there is significant evidence suggesting changes in vaginal microbiota in HPV-positive women. The presence of new bacteria, pathway deregulation, and cytokine overexpression are strongly associated with the progression of cervical dysplasia and chronic inflammation.