Longitudinal Dynamics of HPV16 Antibodies in Saliva and Serum among Pregnant Women

Oral infections with high-risk (hr)HPV genotypes are associated with a subset of head and neck squamous cell carcinomas. Oral hrHPV infections may result from having oral sex, but also from horizontal infection from mouth to mouth. In such cases, saliva can serve as a vehicle for HPV transmission. Still, the prevalence and dynamics of salivary HPV antibodies in healthy non-vaccinated individuals are poorly known and the role of the salivary antibodies in protection from oral HPV infection is unclear. We used an ELISA assay to evaluate the dynamics and correlation of oral HPV16 infection and HPV16L1 and E7 specific antibody levels in saliva and serum samples among 39 women, 13 of which had persistent oral HPV16 infection. The women were mothers-to-be, sampled before delivery and followed up for 36 months postpartum. HPV16L1 IgG and sIgA antibodies were regularly detected in saliva. Antibody levels in serum remained stable during the 36-month follow-up, while antibody levels in saliva fluctuated. There was considerable individual variation in salivary HPV16L1 antibody levels, and some women had persistent oral HPV16 infection but no salivary antibodies. No differences in salivary HPV16L1 levels were found between the women with persistent or transient oral HPV16 infection.