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

Abstract

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.

Keywords: HPV16; IgA; IgG; human papillomavirus; oral; saliva; serum.

Figure 1

Dynamics of saliva and serum HPV16 L1 antibodies of women who had either persistent (blue lines) or transient (yellow lines) oral HPV16 infection. Mean: solid line, 95% confidence, upper and lower: dashed line. (A) saliva sIgA, (B) saliva IgG, (C) serum IgA, and (D) serum IgG.

Figure 2

IgA levels in saliva samples that were collected at the time point when HPV16 DNA was detected (positive, n = 73) or not detected (negative, n = 144) in the oral cavity.

Figure 3

Correlation of serum anti-HPV16L1 IgG (A), anti-HPV16L1 IgA (B), saliva anti-HPV16L1 IgG (C), and anti-HPV16L1 IgA (D) levels of the same individual at different time points. The Ig values were measured from saliva and serum samples collected during pregnancy and compared to values measured from samples collected 36 months after delivery.

Figure 4

(A–C) Individual saliva and serum (s)IgA/IgG HPV16L1 responses to oral and genital HPV16 infections. The columns represent genital (HPVgen) and oral HPV16DNA (HPVoral) DNA positivity at different time points, and the lines show the levels of serum and saliva antibodies, as indicated.