Association of the vaginal microbiota with human papillomavirus infection in a Korean twin cohort

Abstract

Human papillomavirus (HPV) is the most important causative agent of cervical cancers worldwide. However, our understanding of how the vaginal microbiota might be associated with HPV infection is limited. In addition, the influence of human genetic and physiological factors on the vaginal microbiota is unclear. Studies on twins and their families provide the ideal settings to investigate the complicated nature of human microbiota. This study investigated the vaginal microbiota of 68 HPV-infected or uninfected female twins and their families using 454-pyrosequencing analysis targeting the variable region (V2-V3) of the bacterial 16S rRNA gene. Analysis of the vaginal microbiota from both premenopausal women and HPV-discordant twins indicated that HPV-positive women had significantly higher microbial diversity with a lower proportion of Lactobacillus spp. than HPV-negative women. Fusobacteria, including Sneathia spp., were identified as a possible microbiological marker associated with HPV infection. The vaginal microbiotas of twin pairs were significantly more similar to each other than to those from unrelated individuals. In addition, there were marked significant differences from those of their mother, possibly due to differences in menopausal status. Postmenopausal women had a lower proportion of Lactobacillus spp. and a significantly higher microbiota diversity. This study indicated that HPV infection was associated with the composition of the vaginal microbiota, which is influenced by multiple host factors such as genetics and menopause. The potential biological markers identified in this study could provide insight into HPV pathogenesis and may represent biological targets for diagnostics.

Figure 1. Comparison of the vaginal microbiotas of the study population.

(A) Heatmap of abundances of members of the vaginal microbiota; red indicates a high proportion and blue shows a low proportion. (B) Comparison of HPV-negative women (N = 26) and HPV-positive those (N = 19) without CIN. (C) Comparison of HPV-negative (N = 26) and women infected with high-risk HPV types (N = 13) without CIN.

Figure 2. The effect of menopause on the vaginal microbiota.

(A) Rarefaction curves for postmenopausal women (N = 18) and premenopausal women without either HPV infection or CIN (N = 26). (B) Microbiological markers of postmenopausal (N = 18) and premenopausal women without either HPV infection or CIN (N = 26) by LEfSe.

Figure 3. A comparison of the vaginal microbiota among nine HPV infection-discordant twin pairs (N = 18).

(A) Heatmap of the vaginal microbiota at the species levels of HPV infection-discordant MZ twin pairs (N = 9 each for HPV [+] and [−]). (B) Rarefaction curve for the vaginal microbiota (mean ±95% confidence interval) of nine HPV infection-discordant MZ twin pairs (N = 18). (C) Average weighted UniFrac distance between the discordant MZ twin pairs (nine pairs [N = 18]) (***P<10⁻⁸). (D) HPV-negative and HPV-positive women in nine MZ HPV-discordant twin pairs (N = 18).

Figure 4. Average weighted (A) and unweighted (B) UniFrac distances between twin pairs, twins and mothers, and unrelated individuals (Student’s t-test; mean ± SEM; *P<0.05, **P<10⁻⁴,; MZ = 13 pairs (N = 26), MZ’s mother = 8, MZ’s sister = 8).