Sustained Cross-reactive Antibody Responses After Human Papillomavirus Vaccinations: Up to 12 Years Follow-up in the Finnish Maternity Cohort.

BACKGROUND: Human papillomaviruses (HPV) cause several human cancers. Bivalent (Cervarix) and quadrivalent (qGardasil) HPV vaccines both contain virus-like particles of the major oncogenic HPV types 16 and 18, but also cross-protect against some nonvaccine types. However, data on long-term sustainability of the cross-reactive antibody responses to HPV vaccines are scarce. METHODS: Serum samples donated 7-12 years after immunization at age 16-17 years with bivalent (n = 730) or quadrivalent (n = 337) HPV vaccine were retrieved from the population-based Finnish Maternity Cohort biobank. Serum antibody levels against HPV types 6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, and 73 were determined using multiplex pseudovirion binding assay. Antibody avidity was assessed using ammonium thiocyanate treatment. RESULTS: Seropositivity for HPV31, 33, 35, 45, 51, 52, 58, 59, 68, and 73 was increasingly common (P ≤ .001; χ 2 test for trend for each of these types) when women had high anti-HPV16 antibody levels. For 8 nonvaccine HPV types seropositivity was more common among recipients of bivalent than quadrivalent vaccine, in particular for HPV31, 35, 45, 51, 52, and 58 (P < .001). Antibody avidity was higher in the quadrivalent vaccine recipients for HPV6, 11, and two of the nonvaccine types, but lower for HPV16 and 18 (P < .001). CONCLUSIONS: Both vaccines elicit cross-reactive antibodies detectable even 12 years after vaccination. Cross-reactive seropositivity is more common in women with high anti-HPV16 antibody response and in the bivalent vaccine recipients.

Human papillomavirus seroprevalence in pregnant women following gender-neutral and girls-only vaccination programs in Finland: A cross-sectional cohort analysis following a cluster randomized trial.

BACKGROUND: Cervical cancer elimination through human papillomavirus (HPV) vaccination programs requires the attainment of herd effect. Due to its uniquely high basic reproduction number, the vaccination coverage required to achieve herd effect against HPV type 16 exceeds what is attainable in most populations. We have compared how gender-neutral and girls-only vaccination strategies create herd effect against HPV16 under moderate vaccination coverage achieved in a population-based, community-randomized trial. METHODS AND FINDINGS: In 2007-2010, the 1992-1995 birth cohorts of 33 Finnish communities were randomized to receive gender-neutral HPV vaccination (Arm A), girls-only HPV vaccination (Arm B), or no HPV vaccination (Arm C) (11 communities per trial arm). HPV16/18/31/33/35/45 seroprevalence differences between the pre-vaccination era (2005-2010) and post-vaccination era (2011-2016) were compared between all 8,022 unvaccinated women <23 years old and resident in the 33 communities during 2005-2016 (2,657, 2,691, and 2,674 in Arms A, B, and C, respectively). Post- versus pre-vaccination-era HPV seroprevalence ratios (PRs) were compared by arm. Possible outcome misclassification was quantified via probabilistic bias analysis. An HPV16 and HPV18 seroprevalence reduction was observed post-vaccination in the gender-neutral vaccination arm in the entire study population (PR16 = 0.64, 95% CI 0.10-0.85; PR18 = 0.72, 95% CI 0.22-0.96) and for HPV16 also in the herpes simplex virus type 2 seropositive core group (PR16 = 0.64, 95% CI 0.50-0.81). Observed reductions in HPV31/33/35/45 seroprevalence (PR31/33/35/45 = 0.88, 95% CI 0.81-0.97) were replicated in Arm C (PR31/33/35/45 = 0.79, 95% CI 0.69-0.90). CONCLUSIONS: In this study we only observed herd effect against HPV16/18 after gender-neutral vaccination with moderate vaccination coverage. With only moderate vaccination coverage, a gender-neutral vaccination strategy can facilitate the control of even HPV16. Our findings may have limited transportability to other vaccination coverage levels. TRIAL REGISTRATION: ClinicalTrials.gov number NCT00534638, https://clinicaltrials.gov/ct2/show/NCT00534638.

Human papillomavirus types in cervical dysplasia among young HPV-vaccinated women: Population-based nested case-control study.

Human papillomavirus (HPV) vaccines protect against infections with the most oncogenic HPV types, cervical intraepithelial neoplasia (CIN) and cervical cancer. We investigated whether development of cervical intraepithelial neoplasia (CIN) lesions in HPV-vaccinated women is associated with vaccine-targeted HPV types or not. Linkage of the Swedish vaccination and cervical screening registries identified all females born 1980-2000 who had been HPV vaccinated before December 31, 2014 (n = 305,320) and had attended cervical screening in 2006-2018 (n = 79,491). We further selected women HPV vaccinated below 17 years of age and screened in the capital region (n = 5,874). Among those, 125 developed CIN and had a cervical cryopreserved sample available (42.5% of all eligible CIN cases). After 1:2 matching to disease-free HPV vaccinated controls (n = 242), samples were analyzed for HPV DNA and associations between HPV type and CIN diagnosis were estimated with conditional logistic regression. Vaccine-targeted HPV types were rare among both CIN cases (2.4% HPV16, 0.8% HPV18) and their matched controls (0.4% HPV16 and 18). No woman had HPV6 or 11. The CIN lesions were associated with the nonvaccine HPV types 31, 33, 42, 45, 51, 52, 56, 59 and 66. CIN lesions among young HPV vaccinated women are mostly attributable to infection with nonvaccine HPV types. The phenomenon may be important for surveillance and design of cervical cancer control strategies.

Long-term follow-up of human papillomavirus type replacement among young pregnant Finnish females before and after a community-randomised HPV vaccination trial with moderate coverage.

Large scale human papillomavirus (HPV) vaccination against the most oncogenic high-risk human papillomavirus (HPV) types 16/18 is rapidly reducing their incidence. However, attempts at assessing if this leads to an increase of nonvaccine targeted HPV types have been hampered by several limitations, such as the inability to differentiate secular trends. We performed a population-based serological survey of unvaccinated young women over 12 years. The women were under 23-years-old, residents from 33 communities which participated in a community-randomised trial (CRT) with approximately 50% vaccination coverage. Serum samples were retrieved pre-CRT and post-CRT implementation. Seropositivity to 17 HPV types was assessed. HPV seroprevalence ratios (PR) comparing the postvaccination to prevaccination era were estimated by trial arm. This was also assessed among the sexual risk-taking core group, where type replacement may occur more rapidly. In total, 8022 serum samples from the population-based Finnish Maternity Cohort were retrieved. HPV types 16/18 showed decreased seroprevalence among the unvaccinated in communities only after gender-neutral vaccination (PR16/18A = 0.8, 95% CI 0.7-0.9). HPV6/11 and HPV73 were decreased after gender-neutral vaccination (PR6/11A = 0.8, 95% CI 0.7-0.9, PR73A = 0.7, 95% CI 0.6-0.9, respectively) and girls-only vaccination (PR6/11B = 0.8, 95% CI 0.7-0.9, PR73B = 0.9, 95% CI 0.8-1.0). HPV68 alone was increased but only after girls-only vaccination (PR68B = 1.3, 95% CI 1.0-1.7, PRcore68B = 2.8, 95% CI 1.2-6.3). A large-scale, long-term follow-up found no type replacement in the communities with the strongest reduction of vaccine HPV types. Limited evidence for an increase in HPV68 was restricted to girls-only vaccinated communities and may have been due to secular trends (ClinicalTrials.gov number: NCT00534638).

Seropositivity to Multiple Anogenital Human Papillomavirus (HPV) Types Is Associated With Current Anogenital HPV Infection, Abnormal Cytology, and Seropositivity for Nongenital HPVs.

Background: Antibodies against human papillomaviruses (HPVs) are biomarkers for current or past infections. We assessed whether antibodies against multiple HPV types were determinants of current multiple anogenital HPV infections, abnormal cytology, and seropositivity for cutaneous HPVs. Methods: A total of 1848 Slovenian women attended 2 rounds of cervical cancer screening 3 years apart and provided data on HPV antibodies and HPV DNA at both visits. Antibodies against 15 anogenital HPV types and 6 cutaneous HPVs were determined using pseudovirion-Luminex serology and anogenital HPV DNA using Linear Array. Antibodies to polyomaviruses were evaluated as a control. Women were grouped as either HPV seronegative or having antibodies to 1-2 HPV types or to ≥3 HPV types. Results: Presence of antibodies to multiple anogenital HPV types at baseline was associated strongly with (i) presence of HPV DNA at the cervix (χ2 = 68.8; P < .0001), (ii) multiple types of HPV DNA at baseline (χ2 = 58.6; P < .0001), (iii) HPV DNA at follow-up (χ2 = 22.9; P < .0001), (iv) abnormal cytology (χ2 = 9.8; P = .0017), and (v) concomitant presence of antibodies to any of 6 nongenital HPV types (χ2 = 40.1; P < .0001). Presence of antibodies to ≥3 anogenital HPV types tended to persist over time. Conclusions: Seropositivity against at least 3 anogenital HPV types is associated with current multiple anogenital HPV infections, abnormal cytology, and seropositivity to nongenital HPVs.

Long-term Antibody Response to Human Papillomavirus Vaccines: Up to 12 Years of Follow-up in the Finnish Maternity Cohort.

Background: Most cervical cancers are caused by vaccine-preventable infections with human papillomaviruses (HPV). The HPV prophylactic vaccines Gardasil and Cervarix have been widely used for >10 years and are reported to induce high antibody levels. A head-to-head comparison of the antibody responses induced by the 2 vaccines has been performed only up to 5 years. Methods: Among 3300 Finnish females aged 16-17 years who got 1 of the 2 HPV vaccines in phase 3 licensure trials, virtually all consented to registry-based long-term follow-up. Linkage with the Finnish Maternity Cohort found that they donated >2500 serum samples up to 12 years later. Sera of 337 (38.6%) Gardasil and 730 (30.3%) Cervarix vaccine recipients were retrieved from the Finnish Maternity Cohort biobank and type-specific anti-HPV antibody levels were determined using in-house multiplexed heparin-HPV pseudovirion Luminex assay. Results: Anti-HPV-16 and anti-HPV-18 antibody levels remained stable and above natural infection-related antibody levels for up to 12 years for most vaccine recipients. The median antibody levels were higher among Cervarix recipients 7-12 years post vaccination (P < .0001). Conclusions: The stability of vaccine-induced antibody levels is in accordance with the high long-term protection reported previously. The differences in antibody levels induced by the 2 vaccines imply that continued follow-up to identify possible breakthrough cases and estimation of the minimal protective levels of serum antibodies is a research priority.

Seroprevalences of Antibodies to 11 Human Papillomavirus (HPV) Types Mark Cumulative HPV Exposure.

Background: The antibody responses against human papillomavirus type 16 (HPV-16) and HPV-18 are well known, but many genital HPV types are oncogenic. We assessed the correlation between detection of type-specific HPV DNA and antibodies for 11 HPV types. Methods: A total of 2024 women attending the organized national cervical cancer screening program in Slovenia were tested for cervical high-risk HPV DNA (HPV-16, -18, -31, -33, -35, -39, -45, -52, -56, -58, -59, and -68) and serum anti-HPV antibodies. Of these, 1848 women were tested with the same methods 3 years earlier. Results: Type-specific antibodies against 10 of 11 HPV types (HPV-16, -18, -31, -33, -35, -39, -45, -52, -56, and -58) were associated with concomitant presence of type-specific DNA (median odds ratio [OR], 7.5; 95% confidence interval [CI], 2.2-26.1). When the concomitant presence of type-specific HPV DNA at the 3-year visit was combined with the presence of the same HPV DNA type 3 years earlier, the statistical precision was greatly improved, and antibodies against all 11 types (HPV-16, -18, -31, -33, -35, -39, -45, -52, -56, -58, and -59) were associated with the presence of DNA of the same HPV type (median OR, 7.4; 95% CI, 4.2-12.8). Sensitivity had a slight tendency to increase (from 47% to 52%) when DNA positivity at the earlier time point was included, whereas specificity was the same (88%). Seroconversion was associated with previous HPV DNA positivity. Seropositivity mostly remained stable during the observation period. Conclusions: For 11 HPV types, type-specific seropositivity was associated with the presence of DNA of the same HPV type (either concomitantly or previously). Antibodies to these HPV types mark cumulative HPV exposure.

Human Papillomavirus Serology Among Women Living With HIV: Type-Specific Seroprevalence, Seroconversion, and Risk of Cervical Reinfection.

Background: Human papillomavirus (HPV) serodynamics following infection has never been evaluated prospectively among women living with HIV (WLHIV). We determined HPV seroprevalence, seroconversion, and cervical HPV-DNA acquisition among WLHIV. Methods: Prospective study of 604 WLHIV in Johannesburg, South Africa aged 25-50 years. At baseline and 16 months (endline), HPV type-specific antibodies (HPV6/11/16/18/31/33/35/39/45/52/56/58/59/68/73) were measured using HPV-pseudovirions and cervical HPV-DNA genotypes using INNO-LiPA. Results: Seroprevalence of any-HPV was 93.2% and simultaneous seropositivity for HPV types of the bivalent (HPV16/18), quadrivalent (HPV6/11/16/18), and nonavalent (HPV6/11/16/18/31/33/45/52/58) vaccines were 21.4%, 10.9%, and 2.8%. Among 219 women with cervical HPV-DNA, same-type seronegative and without high-grade cervical intraepithelial neoplasia at baseline, 51 (23.3%) had type-specific seroconversion at endline. Risk of type-specific seroconversion was higher among recent antiretroviral therapy users (ART ≤2 years vs ART naive: adjusted OR [aOR] = 2.39; 95% CI, 1.02-5.62), and lower among women with low CD4+ at endline (≤350 vs >350 cells/mm3: aOR = 0.51; 95% CI, 0.24-1.07). Risk of cervical HPV-DNA acquisition was lower in women seropositive for HPV18, 35, and 58 at baseline. Conclusion: WLHIV have evidence of seroconversion in response to baseline HPV-DNA, dependent on CD4+ count and ART. Baseline HPV seropositivity confers limited protection against some HPV types.

Prevalence of human papillomavirus types, viral load and physical status of HPV16 in head and neck squamous cell carcinoma from the South Swedish Health Care Region.

Incidence of human papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HNSCC) is rising in several countries. Intriguingly, large variations of HPV16 viral load and different proportions of the physical viral status among HNSCC have been reported. We analysed fresh biopsies of 275 HNSCC patients from the South Swedish Health Care Region for HPV types with modified general primer PCR and Luminex. Seventy-eight HPV16-positive HNSCC cases were further investigated for viral DNA load and physical status using quantitative PCR for HPV E2 and E7 genes. Presence of intact E2 gene, as a surrogate marker for episomal HPV, was investigated with conventional PCR. Fifteen different HPV types were detected in HNSCC cases and HPV16 was present in 74 % of the HPV-positive cases. HPV was detected in 65 % (92/141) and 11 % (15/134) of oropharyngeal and non-oropharyngeal carcinomas, respectively (P<0.0001). HPV was detected in 73 % (75/103) of tonsillar carcinomas. The median load of HPV16 was 13 copies cell-1 (range 0.003-1080). Among HPV16-positive patients with oropharyngeal carcinoma, metastases to regional lymph nodes were observed in 100 % (17/17) and 68 % (40/58) for those with <1 HPV16 copy cell-1 and >1 HPV16 copy cell-1, respectively (P=0.007). Among HPV16 cases, purely integrated HPV16 was found in 6 %, whereas entirely episomal and mixed virus was detected in 51 and 42 % of cases, respectively. Conclusively, HPV16 viral DNA load demonstrated a large diversity among HNSCCs. Although integration of HPV16 is common (48 %), the episomal HPV16 is salient (93 %) among HPV16 HNSCCs. In addition, low amount of HPV16 was associated with lymph node metastases among oropharyngeal carcinomas.

Prospective study of Merkel cell polyomavirus and risk of Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare type of skin cancer that has a characteristically increased incidence among immunosuppressed subjects. The DNA of Merkel cell polyomavirus (MCV) is regularly found in most MCC tumors. We investigated whether Merkel cell polyomavirus (MCV) infection increases the risk for future MCC. Two large biobank cohorts (Southern Sweden Microbiology Biobank and the Janus Biobank), containing samples from 856,000 healthy donors, were linked to the Cancer Registries in Sweden and Norway to identify cases of MCC occurring up to 30 years after donation of a serum sample. For each of the 22 cases (nine males and 13 females), four matched controls were included. The serum samples were analyzed with an MCV neutralization assay and for IgG antibodies to MCV pseudovirions, using JC polyomavirus and cutaneous human papillomaviruses as control antigens. An increased risk for future MCC was associated both with high levels of MCV antibodies [OR 4.4, 95% CI 1.3-17.4] and with MCV neutralizing activity (OR 5.3, 95% CI 1.3-32.3). In males, MCV seropositivity was not associated to MCC risk, whereas the risk was strongly increased in females, both for high levels of MCV antibodies (OR 7.0, 95% CI 1.6-42.8) and for MCV neutralizing activity (OR 14.3, 95% CI 1.7-677). In conclusion, we found prospective evidence that MCV infection is associated with an increased risk for future MCC, in particular among females.

Lack of detectable HPV18 antibodies in 14% of quadrivalent vaccinees in a longitudinal cohort study.

Although HPV vaccines are highly efficacious, a notable proportion of quadrivalent vaccinees are HPV18 seronegative post-vaccination. We have investigated this findings' validity by comparing vaccine-induced antibody responses using two different immunoassays. 6558 16-17-year-old females participated in the FUTURE II (NCT00092534) and PATRICIA (NCT00122681) trials in 2002-2004. Both the quadrivalent and bivalent vaccine recipients (QVR and BVR) received three doses. Twelve-year follow-up for 648 vaccinees was conducted by the Finnish Maternity Cohort. The presence of neutralising and binding HPV antibodies was analysed via HPV pseudovirion-based neutralisation and pseudovirion-binding assays. Four percent and 14.3% of the QVRs were seronegative for neutralising and binding antibodies to HPV16 and HPV18, respectively. No BVRs were HPV16/18 seronegative post-vaccination. The antibody titres were strongly correlated between the assays, Pearson's correlation coefficient, r[HPV16] = 0.92 and 0.85, and r[HPV18] = 0.91 and 0.86 among the QVRs and BVRs respectively. Fourteen percent of QVRs lacked detectable HPV18 antibodies in long-term follow-up.

Mutations in human papillomavirus type 16 L1 hypervariable surface-exposed loops affect L2 binding and DNA encapsidation.

Prophylactic vaccines against human papillomavirus (HPV) based on virus-like particles (VLP) induce type-specific neutralizing antibodies against a small number of hypervariable residues positioned in surface-exposed loops of the major capsid protein L1. To investigate the importance of these residues for neutralization, cross-neutralization, L2 incorporation and genome encapsidation, ten surface-exposed amino acid residues in four hypervariable loops of L1 were mutated. VLPs containing mutated or WT L1, with or without WT L2, were produced in 293TT cells using pseudovirion expression vectors. The mutations reduced the ability to induce neutralizing antibodies and to incorporate the L2 protein in the capsid. Ability to induce cross-neutralizing antibodies and to encapsidate pseudogenomes were completely abrogated. In summary, the surface-exposed L1 loops are important for the function of the HPV particle.

Pseudovirion-binding and neutralizing antibodies to cutaneous human papillomaviruses (HPV) correlated with the presence of HPV DNA in skin.

Whereas the antibody response to the anogenital human papillomaviruses (HPVs) is known to be mainly type-specific, correlated with the presence of viral DNA and mainly directed to conformational epitopes of the virion, it is not known if this applies also to the antibody response to cutaneous HPVs. For 434 non-immunosuppressed patients with skin lesions (squamous cell carcinoma and basal cell carcinoma of the skin, actinic keratosis and benign skin lesions), we compared HPV DNA status with seroreactivity to HPV pseudovirions (PsV) and to GST-L1 fusion proteins from HPV types -5, -6, -15, -16, -32 and -38. Biopsies from the skin lesions were tested for the presence of HPV DNA using three different PCR methods, with typing by sequencing. Serum samples from subjects with HPV DNA-positive biopsies and randomly selected serum samples from subjects with HPV DNA-negative biopsies were also tested with neutralization assays with HPV5, -38 and -76 PsV. Agreement of the three serological methods varied from poor to moderate. Type-specific seroprevalences among patients positive for the same type of HPV DNA (sensitivity of serology) was improved with the PsV-based method (mean of 40%, maximum 63%) compared with the GST-L1 method (mean of 20%, maximum of 25%). Neutralization was the most sensitive assay for HPV38 (50%). In summary, cutaneous HPVs also appear to induce a type-specific antibody response that correlates with the presence of HPV DNA and that can be detected with improved sensitivity using PsV-based serology.

Antibodies to Merkel cell polyomavirus correlate to presence of viral DNA in the skin.

To validate whether Merkel cell polyomavirus (MCV) serology correlates with MCV infection, we compared real-time polymerase chain reaction results for MCV DNA on fresh-frozen biopsy specimens from various skin lesions and healthy skin from 434 patients to MCV serology results using viruslike particles (VLPs) and MCV neutralization assays. Sixty-five percent of participants were MCV seropositive and 18% were MCV DNA positive. The presence of antibodies was correlated with the presence of virus DNA (odds ratio, 27.85 [95% confidence interval, 6.6-166.5]), with 97% of patients who tested positive for MCV DNA being MCV seropositive. VLP antibody levels correlated to neutralization titers (r=.72), and high antibody levels correlated to high MCV load (P<.01).

Validation of multiplexed human papillomavirus serology using pseudovirions bound to heparin-coated beads.

This study developed and validated a high-throughput human papillomavirus (HPV) serology method based on Luminex technology, using pseudovirions (PsVs) of eight mucosal HPV types (HPV-6, -11, -16, -18, -31, -45, -52 and -58) and two cutaneous HPV types (HPV-5 and -38) bound to heparin-coated beads. Analysis with neutralizing type-specific monoclonal antibodies against the included HPV types indicated the type specificity of the assay. Analysis of negative-control serum samples from 63 children and 71 middle-aged women with up to one lifetime sexual partner indicated high specificity. Positive-control serum samples from subjects with known HPV DNA status or clinical diagnosis found expected sensitivities for most of the HPV types in 219 European serum samples, but lower than expected in 124 samples from Africa. HPV-45 and -52 did not react as expected with the human serum samples. The PsV-Luminex method was used to determine the HPV-seropositivity-associated relative risk for future cervical cancer using 208 serum samples from a prospective study of 18 814 women followed for 23 years, analysed previously with standard HPV-16 ELISA. The PsV-Luminex method gave similar results to ELISA (kappa=0.77). As expected, HPV seropositivities assayed using the PsV-Luminex method found an increased risk of cervical cancer for HPV-16 [odds ratio (OR)=7.7, 95 % confidence interval (CI)=2.6-23] and HPV-31 (OR=4.1, 95 % CI=1.6-10.8), non-significant tendencies for increased risk for other mucosal HPV types and no risk for the cutaneous HPV types. In summary, multiplexed HPV serology using mammalian-derived PsVs selected for native conformation by binding to heparin-coated beads was validated as a high-throughput HPV serological method for most of the analysed HPV types.

Human Papillomavirus Seroprevalence and Seroconversion Among Men Living With HIV: Cohort Study in South Africa.

BACKGROUND: Men living with HIV (MLHIV) have a high burden of human papillomavirus (HPV)-related cancer. Understanding serological dynamics of HPV in men can guide decisions on introducing HPV vaccination and monitoring impact. We determined HPV seroprevalence and evaluated factors associated with HPV seroconversion among MLHIV in Johannesburg, South Africa. METHODS: We enrolled 304 sexually active MLHIV 18 years and older and collected sociobehavioral data, blood samples (CD4 counts, HIV-1 plasma viral load, and HPV serology), and genital and anal swabs [HPV DNA and HPV viral load (VL)] at enrollment and 6-monthly for up to 18 months. Antibodies to 15 HPV types were measured using HPV pseudovirions. Generalized estimating equations were used to evaluate correlates of HPV seroconversion. RESULTS: Median age at enrollment was 38 years (IQR: 22-59), 25% reported >1 sexual partner in the past 3 months, and 5% reported ever having sex with other men. Most participants (65%) were on antiretroviral therapy (ART), with median CD4 count of 445 cells/µL (IQR: 328-567). Seroprevalence for any HPV type was 66% (199/303). Baseline seropositivity for any bivalent (16/18), quadrivalent (6/11/16/18), and nonavalent (6/11/16/18/31/33/45/52/58) vaccine types was 19%, 37%, and 60%, respectively. At 18 months, type-specific seroconversion among 59 men whose genital samples were HPV DNA positive but seronegative for the same type at enrollment was 22% (13/59). Type-specific seroconversion was higher among men with detectable HIV plasma viral load (adjusted odds ratio = 2.78, 95% CI: 1.12 to 6.77) and high HPV VL (adjusted odds ratio = 3.32, 95% CI: 1.42 to 7.74). CONCLUSIONS: Seropositivity and exposure to nonavalent HPV types were high among MLHIV. HPV vaccination of boys before they become sexually active could reduce the burden of HPV infection among this at-risk population.

Effect of naturally acquired type-specific serum antibodies against human papillomavirus type 16 infection.

BACKGROUND: While vaccine-induced antibodies are known to confer protection against incident human papillomavirus (HPV) infection, there is inconsistent data regarding the protective effect of naturally acquired anti-HPV antibodies. OBJECTIVES: To estimate the protective effect of naturally acquired anti-HPV16 serum antibodies against incident anogenital infection with HPV16 in females aged 20-64 years and to assess whether antibodies influence the persistence/clearance of anogenital HPV16 infection. STUDY DESIGN: 4432 women attending the organized national cervical cancer screening program in Slovenia were initially enrolled. 2199 and 1848 women had valid HPV DNA results obtained using PCR-based assays and HPV antibody serotyping results obtained using pseudovirion-based serological assay, at baseline and at three-year follow-up, respectively. RESULTS: Baseline HPV16 seroprevalence was 2.4-fold higher among HPV16 DNA-positive women (55.7% vs. 23.2%; p<0.01). Baseline HPV16 DNA-positive/seronegative women frequently acquired anti-HPV16 antibodies during follow-up (OR=8.2; 95% CI: 3.8-17.8). Baseline anti-HPV16 antibodies persisted at follow-up, irrespective of baseline HPV16 DNA status (OR=40.6; 95% CI: 30.3-54.5). Baseline HPV16 DNA-negative/seropositive women were less likely to acquire HPV16 infection at follow-up (unadjusted OR=0.2; 0.1-0.9). However, the age-adjusted association was non-significant (adjusted OR=0.3; 0.1-1.2). The tendency for protective effect was stronger among women older than 25 years (OR=0.2; 0.03-1.8). Baseline anti-HPV16 antibodies were not associated with persistence/clearance of HPV16 infection at follow-up (OR=0.8; 0.3-1.9). CONCLUSIONS: Naturally acquired anti-HPV16 serum antibodies appeared to protect against anogenital HPV16 infection, but this association was at least partially confounded by age. Baseline anti-HPV16 serum antibodies did not influence persistence/clearance of HPV16 infection at follow-up.

Sourcing of the WHO human papillomavirus type 18 international standards for HPV antibody levels.

BACKGROUND: HPV serology is important for studies of vaccine immunogenicity, but can not be performed in a comparable manner without international standardisation. OBJECTIVES: To find suitable candidate sera from naturally infected persons for use as International Standards (IS) for antibodies to high-risk HPVs, with priority for HPV-18. STUDY DESIGN: 946 healthy Thai women (median age 44, range 18-83) and 61 cervical cancer patients were screened using an HPV pseudovirion-Luminex assay to detect antibodies to genital (HPV-6,-11,-16,-18,-31,-33,-45,-52,-58,-68) and non-genital HPV types (HPV-5,-15,-32,-38 and -76). Suitable candidate sera should ideally be mono-specific (have reactivity against only one genital HPV) and have high antibody levels that are stable over time. RESULTS: Seroprevalences of HPV-16,-31,-52 and -58 were at least twice as high among cancer patients compared to healthy individuals. Thirteen healthy women who met the IS inclusion criteria in initial testing also consented to blood-bag donations. Donations from 2 women with high HPV-18 Ab titers were pooled to the HPV-18 candidate IS, later established as the WHO official IS for HPV antibodies. Sera that could potentially be used as candidate IS for other oncogenic HPVs have also been identified. CONCLUSIONS: In the Thai population, seroepidemiology implicated HPV types HPV-16,-31,-52 and -58 as particularly associated with cervical cancer. A well characterized cohort study has allowed sourcing of materials for an IS for HPV-18 antibodies and could conceivably be used for IS for other HPV types as well.

Cutaneous Human Papillomaviruses and Squamous Cell Carcinoma of the Skin: Nested Case-Control Study.

BACKGROUND: Cutaneous human papillomavirus (HPV) types have been associated with non-melanoma skin cancer (NMSC), including a previous nested case-control study using HPV serology with bacterially derived fusion proteins with the major HPV capsid protein L1 (GST-L1). However, HPV serology using conformationally intact pseudovirions has been shown to correlate better with natural infection. Prospective studies using a more valid marker of infection are therefore warranted. METHODS: Cancer registry follow-up of large Nordic biobanks identified prediagnostic serum samples from 633 subjects who later developed SCC, 1,990 subjects who developed basal cell carcinoma (BCC). The samples from cases and matched controls were tested for IgG to pseudovirions to 16 different HPV types (3, 5, 6, 11, 15: , 16, 18, 31, 32, 33, 38: , 45, 52, 58, 68, and 76: ) and two polyomaviruses (MCPyV and JCPyV). RESULTS: Baseline seropositivity was not associated with SCC risk, and there were only weak associations with BCC risk [HPV-5 (OR, 1.1; 95% confidence interval [CI], 1.0-1.3), HPV-15 (OR, 1.2; 95% CI, 1.0-1.4), HPV-38 (OR, 1.2; 95% CI, 1.0-1.3), and MCPyV (OR, 1.1; 95% CI, 1.0-1.3)]. Acquisition of HPV-5 seropositivity during follow-up was associated with SCC risk (OR, 3.2; 95% CI, 1.3-7.6). Persistent seropositivity for HPV-15 was weakly associated with BCC (OR, 1.4; 95% CI, 1.0-1.9) and HPV-6 antibody persistence was weakly associated with SCC (OR, 2.2; 95% CI, 1.0-4.8). CONCLUSION: Considering the large number of viruses tested, the weak associations found do not support any strong links between studied HPV and NMSC, with the possible exception of HPV-5 seroconversion and SCC. IMPACT: Known alpha and beta papillomaviruses do not appear to be risk factors for NMSC. Cancer Epidemiol Biomarkers Prev; 25(4); 721-4. ©2016 AACR.

Establishment and characterization of a human papillomavirus type 16-positive tonsillar carcinoma xenograft in BALB/c nude mice.

BACKGROUND: Among head and neck cancers, human papillomavirus type 16 (HPV16) is associated with tonsillar carcinomas. Despite this, no HPV16-positive tonsillar cancer cell line has been established in nude mice. METHODS: Fresh tonsillar carcinoma biopsies were obtained from 23 patients and implanted subcutaneously into nude mice (BALB/c, nu/nu). RESULTS: After 7 months, one xenograft was established. The primary tumor harbored 2.7 copies (95% confidence interval = 2.4-2.9) of HPV16/cell and displayed 99.9% (7904/7906) nucleotide identity to HPV16 (EU118173.1). The xenograft showed increased methylation in two E2-binding sites of the HPV16 genome. Both episomal and integrated HPV16 were detected in the original tumor and in 14 xenografts from the second passage. From this passage, a viral load of 6.4 copies/cell (range = 4.6-9.6) and 3.7 (range = 1.0-5.5) E7-mRNA transcripts/HPV16-genome were detected. CONCLUSION: This xenograft represents the first established HPV16-positive tonsillar tumor in nude mice and could provide an experimental system of HPV16-positive tonsillar cancers.