Treatment of latent or subclinical Genital HPV Infection with 5-aminolevulinic acid-based photodynamic therapy

Background: Genital HPV infections are widely prevalent. HPV can persist and be transmitted to partners even after warts are gone. The HPV genotype and viral load assay can reveal whether infections are persistent or latent, and it can serve as a predictor of infection clearance. Although numerous studies have demonstrated that photodynamic therapy (PDT) is effective against condyloma acuminata, there is no data on its effects on latent, persistent infections. Methods: A total of 20 patients with latent or subclinical HPV infection were evaluated. At each patient visit, polymerase chain reaction was used to identify HPV genotypes and measure the viral loads, which reflect the status of HPV infection. We administered 5-aminolevulinic acid (ALA)-based PDT weekly for patients with active infections, while no treatment was administered to patients with regressing infections. Results: PDT treatment can effectively eliminate HPV, significantly reducing viral loads after three rounds of treatment (p < 0.001). The rate of negative HPV DNA test results was higher in patients with latent or subclinical infections than in patients with genital warts after one round of PDT treatment. Conclusions: ALA-PDT can effectively eliminate latent or subclinical HPV infections. Additionally, our assay for identifying HPV genotypes and viral loads, which reflect the status of HPV infection, can accurately guide ALA-PDT treatment.