Natural immune responses against eight oncogenic human papillomaviruses in the ASCUS-LSIL Triage Study

Human papillomavirus seroprevalence and seroconversion following baseline detection of nine human papillomavirus types in young women

Background

Estimates of the humoral immune response to incident human papillomavirus (HPV) infections are limited.

Methods

In this post hoc analysis of 3875 women aged 16–23 years from a 4-valent HPV vaccine trial (NCT00092482), HPV seroprevalence on day 1 was measured with a 9-valent HPV (HPV 6/11/16/18/31/33/45/52/58) competitive Luminex immunoassay and compared with cervical/external genital HPV detection by polymerase chain reaction. In the control group, among women who were HPV DNA‒negative on day 1, seroconversion following initial HPV detection was estimated using Kaplan-Meier methods.

Results

Type-specific HPV seropositivity among women with no day 1 cervical/external genital HPV detection was 0.6%–3.6%. Women with any 9-valent HPV (9vHPV) cervical/external genital detection (796/3875; 20.5%) had concordant seropositivity ranging from 13.4% (HPV 45) to 38.5% (HPV 6). Among women in the control group who were negative for all HPV types on day 1, seroconversion by month 30 after initial detection ranged from 29% (HPV 45) to 75% (HPV 16).

Conclusions

Humoral immune response to HPV is variable and dynamic, depending on type-specific exposure. This longitudinal analysis provides insight into the relationship between incident infection and seropositivity.

ClinicalTrials.gov; NCT00092482 https://clinicaltrials.gov/ct2/show/NCT00092482.

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Research on humoral immune responses to HPV infection are limited.

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HPV-related serologic responses were analyzed in women aged 16–23 years.

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Type-specific HPV seropositivity was low in women without initial HPV DNA detection.

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Concordant seropositivity in women with any 9vHPV DNA detection ranged from 13% to 40%.

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Seroconversion to the same genotype within 30 months of an infection was common.

Changes in HPV Seroprevalence from an Unvaccinated toward a Girls-Only Vaccinated Population in the Netherlands

BACKGROUND

In the Netherlands, bivalent human papillomavirus (HPV) vaccination was included in the National Immunization Program for 12-year-old girls in 2010 (vaccination coverage, 45%-60%). We examined possible changes in HPV seroprevalence in the HPV-unvaccinated Dutch population aged 0-89 years, comparing prevaccination data with data of approximately 6 years after implementation of national vaccination.

METHODS

Serum samples of men and women were used from two cross-sectional population-based serosurveillance studies performed before (2006-07, n = 6,384) and after (2016-17, n = 5,645) implementation of HPV vaccination in the Netherlands. Seven high-risk HPV-specific antibodies (HPV16, 18, 31, 33, 45, 52, and 58) were tested in a virus-like particle-based multiplex immunoassay.

RESULTS

Type-specific HPV seroprevalence increased in women between 2006-07 and 2016-17. Also, a higher seroprevalence for at least one type in women >15 years was found in 2016-17 (31.7%) compared with 2006-07 (25.2%). In men, overall HPV seroprevalence remained similar; however, a lower seroprevalence was found for HPV16 in 2016-17 (7.5%) compared with 2006-07 (10.6%).

CONCLUSIONS

Our results indicate an increase in high-risk HPV types in women and a rather stable exposure in men. No clear effects of the strategy of girls-only vaccination were observed in men, probably because of the short time after introduction combined with suboptimal coverage.

IMPACT

No herd immunity has been observed yet in a population with suboptimal HPV vaccination coverage.

High seroprevalence of multiple high-risk human papillomavirus types among the general population of Bonaire, St. Eustatius and Saba, Caribbean Netherlands

BACKGROUND

Incidence and mortality of human papillomavirus (HPV)-related cancers differs geographically, with high rates in Caribbean countries. Seroepidemiological data provide information on lifetime cumulative HPV exposure and contributing risk factors, but has not been available yet for Caribbean Netherlands (CN), comprising the islands Bonaire, St. Eustatius and Saba. Therefore, a cross-sectional population-based serosurveillance study was performed in this (recently girls-only HPV-vaccinated) population in 2017.

METHODS

Blood samples from participants (n = 1,823, 0-90 years) were tested for seven high-risk (hr)-HPV-specific IgG-antibodies using a VLP-based multiplex-immunoassay. Risk factors for HPV-seropositivity were analysed among persons unvaccinated aged ≥ 15 years who ever had sex (n = 1,080).

RESULTS

Among unvaccinated individuals aged ≥ 15 years, overall seropositivity was high (34%), with over half of them being seropositive for ≥ 2 hr-HPV types, and HPV16 and 52 being most prevalent (13%). Seroprevalence was substantial higher in unvaccinated women (51%) than men (18%), predominantly peaking in women aged 20-59 years, and was highest on St. Eustatius (38%). Besides age and sex, sexual risk factors were associated with HPV-seropositivity.

CONCLUSIONS

In accordance with the Caribbean region, seroprevalence of multiple hr-HPV types was high in CN. These data corroborate the decision regarding introduction of a sex-neutral HPV-vaccination program and the relevance for considering a population-based cervical cancer screening program.

Age-Structured Population Modeling of HPV-related Cervical Cancer in Texas and US

Human papillomavirus (HPV)-related cervical cancer is a major public health threat to women, with >10,000 new cases diagnosed annually in the United States between 2008 and 2012. Since HPV vaccines can protect against ~80% of HPV-associated cervical cancers, the economic and epidemiological impacts of HPV vaccination have been extensively investigated, particularly at the national level. However, vaccination policies are state-specific, and state-level models are required for state-specific policy decisions. This study adapted an age-structured population model to describe the dynamics of HPV-related cervical cancer in Texas, with model parameters calibrated for Texas. The Year 2000 parameter set was the start point, and the model's predictions from 2001-2010 were well matched with the real incidence numbers in 23 age groups, suggesting the validity of the model. Application of the model to the Year 2010 parameter set predicted that, over the next 10 decades, incidence would decrease rapidly within the first decade and more slowly thereafter. Sensitivity analysis determined the impact of selected parameters (e.g., vaccine coverage rate) on future disease incidence. When compared with the US parameter sets, the Texas population was more sensitive to changes in HPV transmission and vaccination (e.g., ~8% difference in the predicted disease decline).

Smoking and subsequent human papillomavirus infection: a mediation analysis

PURPOSE

Smoking is an established risk factor for a human papillomavirus (HPV) infection advancing to cervical precancer and cancer, but its role earlier in the natural history is less clear. Smoking is inversely associated with possessing HPV antibodies from a past infection suggesting that smoking may influence acquiring subsequent infections.

METHODS

In a cohort of 1976 U.S. women, we evaluate whether reduced antibodies to HPV-16 is a mechanism for smoking's role on acquiring a subsequent HPV-16 infection, through the analytic technique of causal mediation analysis. We posit a causal model and estimate two counterfactually defined effects: a smoking impaired antibody-mediated indirect effect and a nonmediated direct effect representing all other potential mechanisms of smoking.

RESULTS

Compared to never smokers, current smokers had increased odds of HPV-16 infection by the antibody-mediated indirect effect (odds ratio [OR] = 1.29; 95% confidence interval [CI]: 1.11, 1.73); the estimated direct effect was very imprecise (OR = 0.57; 95% CI, 0.26-1.13). We observed a stronger estimated indirect effect among women who smoked at least half a pack of cigarettes daily (OR = 1.61, 95% CI, 1.27-2.15) than among women who smoked less than that threshold (OR = 1.09; 95% CI, 0.94-1.44).

CONCLUSIONS

This is the first study to directly test the mechanism underlying smoking as an HPV cofactor. The results support current smoking as a risk factor earlier in the natural history of HPV and are consistent with the hypothesis that smoking increases the risk of a subsequent infection by reducing immunity.

Determinants of High-Risk Human Papillomavirus Seroprevalence and DNA Prevalence in Mid-Adult Women

BACKGROUND

The epidemiology of high-risk human papillomavirus (hrHPV) infections in mid-adult women is not well understood.

METHODS

We conducted a cross-sectional analysis of 379 women 30 to 50 years of age. Vaginal samples were tested for type-specific HPV DNA by polymerase chain reaction. Sera were tested for type-specific HPV antibodies by Luminex-based assay. Assays included 13 hrHPV types (16/18/31/33/35/39/45/51/52/56/58/59/68). Self-reported health and sexual history were ascertained. Risk factors for seropositivity and DNA positivity to hrHPV were assessed in separate Poisson regression models.

RESULTS

The mean (SD) age of participants was 38.7 (6.1) years, and the median lifetime number of male sex partners was 7. Approximately two-thirds (68.1%) were seropositive for any hrHPV, 15.0% were DNA positive, and 70.7% were seropositive or DNA positive. In multivariate analyses, women who were married/living with a partner were less likely to be seropositive than single/separated women (adjusted prevalence ratio [aPR], 0.86; 95% confidence interval [CI], 0.75-0.98). Compared with never hormonal contraceptive users, current (aPR, 1.53; 95% CI, 1.01-2.29) or former (aPR, 1.64; 95% CI, 1.10-2.45) users were more likely to be seropositive. Women with a lifetime number of sex partners of 12 or more were more likely to be seropositive compared with those with 0 to 4 partners (aPR, 1.29; 95% CI, 1.06-1.56). Similar associations were seen with DNA positivity. In addition, there was a positive association between current smoking and hrHPV DNA (aPR vs. never smokers, 2.51; 95% CI, 1.40-4.49).

CONCLUSIONS

Seventy-one percent of mid-adult women had evidence of current or prior hrHPV infection. Measures of probable increased exposure to HPV infection were associated with both seropositivity and DNA positivity to hrHPV, whereas current smoking was positively associated with hrHPV DNA only.

Transformation of the genital epithelial tract occurs early in California sea lion development

An unusually high prevalence of metastatic urogenital carcinoma has been observed in free-ranging California sea lions stranded off the coast of California in the past two decades. No cases have been reported for sea lions in the relatively unpolluted Gulf of California. We investigated occurrence of genital epithelial transformation in 60 sea lions (n=57 pups and 3 adult females) from the Gulf of California and examined whether infection by a viral pathogen previously found to be associated with urogenital carcinoma accounted for such alterations. We also explored the contribution of MHC class II gene expression on transformation. Cellular alterations, such as squamous cell atypia (ASC), atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesions were observed in 42% of the pups and in 67% of the adult females. Normal genital epithelium was more common in male than female pups. ASC was five times more likely to occur in older pups. Epithelial alterations were unrelated to infection by the potentially oncogenic otarine type I gammaherpesvirus (OtHV-1), but ASCUS was more common in pups with marked and severe inflammation. Expression of MHC class II DRB loci (Zaca DRB-D) by peripheral antigen-presenting leucocytes showed a slightly 'protective' effect for ASC. We propose that transformation of the California sea lion genital epithelium is relatively common in young animals, increases with age and is probably the result of infection by an unidentified pathogen. Expression of a specific MHC class II gene, suggestive of presentation of specific antigenic peptides to immune effectors, appears to lower the risk of transformation. Our study provides the first evidence that epithelial transformation of the California sea lion genital tract is relatively common, even from an early age, and raises questions regarding differences in sea lion cancer-detection and -repair success between geographical regions.

Humoral Immune Response Against Human Papillomavirus as Source of Biomarkers for the Prediction and Detection of Cervical Cancer

Cervical cancer (CC) is one of the main causes of death among women of reproductive age. Although there are different tests, the disease tends to be diagnosed at late stages. In recent years, the use of complementary tests or sequential diagnostic tests has been implemented. Nevertheless, the results are variable and not conclusive; therefore, more studies for improving the usefulness of these tests in diagnostics are necessary. The human papillomavirus (HPV) infection has been associated with both benign and malignant proliferation of skin and mucosal tissues. Furthermore, some HPV types have been classified as high risk due to their potential to cause cancer, and HPV16 is most frequently associated with this disease. Although between 70% and 80% of precancerous lesions are eliminated by the host's immune system, there is no available test to distinguish between regressive lesions from those that could progress to CC. An HPV infection generates a humoral immune response against L1 and L2 capsid proteins, which can be protective and a response against early proteins. The latter is not a protective response, but these antibodies can be used as markers to determine the stage of the infection and/or the stage of the cervical lesion. Up to now, the humoral immune response resulting from the HPV infection has been used to study the biology of the virus and the efficacy of the HPV vaccines. Although there are no conclusive results regarding the use of these antibodies for diagnosis, we hereby review the actual panorama of the antibody response against the HPV proteins during the development of the disease as well as their possible use as biomarkers for the progression of cervical lesions and of CC.

Prior human polyomavirus and papillomavirus infection and incident lung cancer: a nested case-control study

PURPOSE

To test whether infection with select human polyomaviruses (HPyV) and human papillomaviruses (HPV) is associated with incident lung cancer.

METHODS

We performed a nested case-control study, testing serum from the carotene and retinol efficacy trial, conducted 1985-2005, for antibodies to Merkel cell (MCV), KI (KIV), and WU (WUV) HPyVs as well as to six high-risk and two low-risk HPV types. Incident lung cancer cases (n = 200) were frequency-matched with controls (n = 200) on age, enrollment and blood draw dates, intervention arm assignment, and the number of serum freeze/thaw cycles. Sera were tested using multiplex liquid bead microarray antibody assays. We used logistic regression to assess the association between HPyV and HPV antibodies and lung cancer.

RESULTS

There was no evidence of a positive association between levels of MCV, KIV, or WUV antibodies and incident lung cancer (p corrected >0.10 for all trend tests; odds ratio (OR) range 0.72-1.09, p corrected >0.10 for all). There was also no evidence for a positive association between HPV 16 or 18 infection and incident lung cancer (p corrected ≥0.10 for all trend tests; OR range 0.25-2.54, p > 0.05 for all OR > 1), but the number of persons with serologic evidence of these infections was small.

CONCLUSIONS

Prior infection with any of several types of HPyV or HPV was not associated with subsequent diagnosis of lung cancer. Infection with these viruses likely does not influence a person's risk of lung cancer in Western smoking populations.

A longitudinal study of human papillomavirus 16 L1, e6, and e7 seropositivity and oral human papillomavirus 16 infection

BACKGROUND

Individuals with human papillomavirus (HPV) infections can develop IgG antibodies to HPV proteins including the L1 capsid and E6 and E7 oncoproteins. Evidence on whether L1 antibodies reduce the risk of cervical HPV infection is mixed, but this has not been explored for oral HPV infections. Antibodies to HPV16's E6 oncoprotein have been detected in some oropharyngeal cancer cases years before cancer diagnosis, but it is unknown if these antibodies are associated with oral HPV16 DNA.

METHODS

Enzyme-linked immunosorbent assays tested for serum antibodies to HPV16's L1 capsid in 463 HIV-infected and 293 HIV-uninfected adults, and for antibodies to recombinantly expressed E6 and E7 oncoproteins to HPV16 in 195 HIV-infected and 69 HIV-uninfected cancer-free participants at baseline. Oral rinse samples were collected semiannually for up to 3 years and tested for HPV DNA using PGMY 09/11 primers. Adjusted Poisson, logistic, and Wei-Lin-Weissfeld regression models were used.

RESULTS

Human papillomavirus 16 L1 seroreactivity did not reduce the subsequent risk of incident oral HPV16 infection in unadjusted (hazard ratio, 1.4; 95% confidence interval, 0.59-3.3) or adjusted (adjusted hazard ratio = 1.1; 95% confidence interval, 0.41-3.0) analysis. Antibodies to HPV16 E6 and E7 oncoproteins were detected in 7.6% and 3.4% of participants, respectively, but they were not associated with baseline oral HPV16 DNA prevalence or oral HPV16 persistence (each P > 0.40).

CONCLUSIONS

Naturally acquired HPV16 L1 antibodies did not reduce the risk of subsequent oral HPV16 infection. Human papillomavirus 16 E6 and E7 seropositivity was not a marker for oral HPV16 infection in this population without HPV-related cancer.

Human papillomavirus 16/18 seroprevalence in unvaccinated women over 30 years with normal cytology and with high grade cervical abnormalities in Australia: results from an observational study

Background

Australia commenced human papillomavirus (HPV) vaccination in 2007, with a two-year catch-up to the age of 26; catch-up cohorts are thus now entering their thirties. Plans for monitoring vaccine impact involve pre- and post-vaccination assessment of cervical HPV DNA in the general population and in high grade abnormalities. Although HPV serology is less sensitive than DNA genotyping, it assesses lifetime exposure and may be easier to measure in the general population. However, benchmark pre-vaccination seroprevalence of vaccine-included types in unvaccinated women with high grade abnormalities has not previously been reported.

Methods

We assessed seroprevalence for HPV16/18 from a population-based sample of 3,729 women with normal cytology and 971 women with confirmed high grade abnormalities (CIN2/3), aged 30–64 years, unvaccinated, and recruited in New South Wales in 2006–2010. We examined the variation in HPV16/18 seropositivity by age and in relation to a range of reproductive and behavioural characteristics in the subgroup of normal cytology women with no recent history of high grade cervical disease.

Results

The HPV 16, 18 and combined seroprevalence was 19%, 7% and 24% among women with normal cytology, and 39%, 13% and 44% among women with CIN2/3, respectively. For both groups, HPV16/18 seroprevalence was highest at age 30–39 years and decreased with age. In multivariable analysis for women with normal cytology, HPV16 and HPV18 seropositivity were each associated with the number of lifetime sexual partners (p-trend <0.001 and 0.052, respectively) and for HPV16 this was also associated with age (p-trend <0.001) and prior diagnosis of Chlamydia (adjusted OR 1.89, 95% CI 1.27-2.80).

Conclusions

The findings of this study inform pre-vaccination estimates of HPV seropositivity in women with normal cytology and women with high grade abnormalities. Almost a quarter of unvaccinated women aged over 30 years with normal cytology, and more than 40% of those with CIN2/3, had seroconverted to HPV 16 or 18. These findings provide a potential additional benchmark for assessing the effects of HPV vaccination.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0676-z) contains supplementary material, which is available to authorized users.

Serological prevalence and persistence of high-risk human papillomavirus infection among women in Santiago, Chile

Background

Human papillomavirus (HPV) serology is a main factor for designing vaccination programs and surveillance strategies; nevertheless, there are few reports of HPV seroprevalence in the general population, especially in Latin America. This study aimed to describe high-risk HPV serological prevalence, persistence, and association with concurrent cervical infection, in Chilean women.

Methods

1021 women from the general population, aged 15–85 years, were studied in 2001 of whom 600 were reexamined in 2006. The assessments at both time points included cervical HPV DNA testing, HPV antibody testing, cervical cytology and a sociodemographic/behavioral questionnaire. HPV DNA and antibodies against L1 protein of types 16, 18, 31, 33, 35, 45, 52, and 58 were assessed by reverse line blot and multiplex serology, respectively.

Results

Seropositivity was high at both baseline (43.2%) and follow-up (50.2%) and increased with age (p < 0.001); corresponding DNA prevalences were 6.7% and 8.7%. DNA and seroprevalence were associated at baseline (p = 0.01 for any HPV). Early age at first sexual intercourse and having had two or more sexual partners were independently associated with seropositivity. Most (82.0%) initially seropositive women remained seropositive at follow-up; 21.6% of initially seronegative women seroconverted, reaching 17.5% among women older than 60 years of age. ASCUS or worse cytology was correlated with HPV DNA positivity but not with HPV seropositivity.

Conclusion

HPV seroprevalence studies are a useful tool for learning about the dynamics of HPV infection in a community. This study contributes to understanding the natural history of HPV infection and provides a baseline assessment before the incorporation of HPV vaccination into a national program.

Glutathione S-transferase L1 multiplex serology as a measure of cumulative infection with human papillomavirus

BACKGROUND

Several assays are used to measure type-specific serological responses to human papillomavirus (HPV), including the bead-based glutathione S-transferase (GST)-L1 multiplex serology assay and virus-like particle (VLP)-based ELISA. We evaluated the high-throughput GST-L1, which is increasingly used in epidemiologic research, as a measure of cumulative HPV infection and future immune protection among HPV-unvaccinated women.

METHODS

We tested enrollment sera from participants in the control arm of the Costa Rica Vaccine Trial (n = 488) for HPV16 and HPV18 using GST-L1, VLP-ELISA, and two assays that measure neutralizing antibodies (cLIA and SEAP-NA). With statistical adjustment for sampling, we compared GST-L1 serostatus to established HPV seropositivity correlates and incident cervical HPV infection using odds ratios. We further compared GST-L1 to VLP-ELISA using pair-wise agreement statistics and by defining alternate assay cutoffs.

RESULTS

Odds of HPV16 GST-L1 seropositivity increased with enrollment age (OR = 1.20 per year, 95%CI 1.03-1.40) and lifetime number of sexual partners (OR = 2.06 per partner, 95%CI 1.49-2.83), with similar results for HPV18. GST-L1 seropositivity did not indicate protection from incident infection over 4 years of follow-up (HPV16 adjusted OR = 1.72, 95%CI 0.95-3.13; HPV18 adjusted OR = 0.38, 95%CI 0.12-1.23). Seroprevalence by GST-L1 (HPV16 and HPV18, respectively) was 5.0% and 5.2%, compared to 19.4% and 23.8% by VLP-ELISA, giving positive agreement of 39.2% and 20.8%. Lowering GST-L1 seropositivity cutoffs improved GST-L1/VLP-ELISA positive agreement to 68.6% (HPV16) and 61.5% (HPV18).

CONCLUSIONS

Our data support GST-L1 as a marker of cumulative HPV infection, but not immune protection. At lower seropositivity cutoffs, GST-L1 better approximates VLP-ELISA.

Seroprevalence of 8 oncogenic human papillomavirus genotypes and acquired immunity against reinfection

BACKGROUND

Natural human papillomavirus (HPV) antibody titers have shown protection against subsequent HPV infection, but previous studies were restricted to few HPV genotypes. We examined the association of naturally occurring antibodies against 8 carcinogenic HPV types with subsequent infections.

METHODS

A total of 2302 women enrolled in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study provided blood samples at baseline. Serum samples were tested for antibodies against 8 carcinogenic HPV genotypes (16, 18, 31, 33, 35, 45, 52, and 58) using a multiplex serology assay. We analyzed the relationship between HPV antibodies and HPV infection during 2 years of follow-up among women negative for the specific HPV type at baseline.

RESULTS

Baseline seroprevalence for HPV16 L1 was associated with decreased risk of DNA positivity for HPV16 (odds ratio, 0.39 [95% confidence interval, .18-.86]) at ≥2 follow-up visits. We observed similar but nonsignificant decreased risks for HPV18 and 31. These findings were restricted to women reporting a new sex partner during follow-up. There was no association between baseline seroprevalence and detection of precancer during follow-up.

CONCLUSIONS

Seroprevalence conferred protection against subsequent HPV infection for HPV16 and indicated possible protection for 2 other genotypes, suggesting that this effect is common to several HPV genotypes.