Harnessing the Power of Microbiota: How Do Key Lactobacillus Species Aid in Clearing High-Risk Human Papilloma Virus Infection and Promoting the Regression of Cervical Dysplasia?

Lactobacillus species play a fundamental role in maintaining a healthy vaginal microbiota and have been increasingly recognized for their protective effects against high-risk human papillomavirus (HR-HPV) infection and the progression of cervical intraepithelial neoplasia (CIN). These beneficial bacteria contribute to host defense through multiple mechanisms, including the production of lactic acid that sustains a low vaginal pH, enhancement of epithelial barrier integrity via E-cadherin regulation, and modulation of immune signaling pathways such as interferon responses and NF-κB activity. Lactobacillus strains exert anti-inflammatory effects by downregulating pro-inflammatory cytokines and interfering with oncogenic pathways including Wnt/β-catenin and the expression of HPV E6 and E7 proteins. Additionally, they may regulate tumor-suppressor microRNAs and modulate dendritic cell and macrophage activity, supporting antiviral immunity. Recent studies have explored their potential influence on CIN regression and HR-HPV clearance, particularly the strains Lactobacillus crispatus and L. gasseri, which are associated with favorable microbial community states. This review explores the potential mechanisms through which Lactobacillus species contribute to HR-HPV clearance and the regression of cervical dysplasia, integrating evidence from molecular studies, in vivo models, and clinical trials. The emerging role of probiotic interventions as adjunctive strategies in HPV management is also discussed, highlighting their possible synergy with conventional treatments and prophylactic vaccination.