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Background: Clinical trials in the research setting have demonstrated that primary human papillomavirus (HPV)-based screening results in greater protection against cervical cancer compared with cytology, but evidence from real-life implementation was missing. To evaluate the effectiveness of HPV-based cervical screening within a real-life screening program, the organized, population-based cervical screening program in the capital region of Sweden offered either HPV- or cytology-based screening in a randomized manner through a randomized healthcare policy (RHP)., Methods and Findings: A total of 395,725 women aged 30 to 64 years that were invited for their routine cervical screening visit were randomized without blinding to either cytology-based screening with HPV triage (n = 183,309) or HPV-based screening, with cytology triage (n = 212,416 women) between September 1, 2014 and September 30, 2016 and follow-up through June 30, 2017. The main outcome was non-inferior detection rate of cervical intraepithelial neoplasia grade 2 or worse (CIN2+). Secondary outcomes included superiority in CIN2+ detection, screening attendance, and referral to histology. In total, 120,240 had a cervical screening sample on record in the study period in the HPV arm and 99,340 in the cytology arm and were followed for the outcomes of interest. In per-protocol (PP) analyses, the detection rate of CIN2+ was 1.03% (95% confidence interval (CI) 0.98 to 1.10) in the HPV arm and 0.93% (0.87 to 0.99) in the cytology arm (p for non-inferiority <0.0001; odds ratio (OR) 1.11 (95% CI 1.02 to 1.22)). There were 46 cervical cancers detected in the HPV arm (0.04% (0.03 to 0.06)) and 48 cancers detected in the cytology arm (0.05% (0.04 to 0.07)) (p for non-inferiority <0.0001; OR 0.79 (0.53 to 1.18)). Intention-to-screen (ITS) analyses found few differences. In the HPV arm, there was a modestly increased attendance after new invitations (68.56% (68.31 to 68.80) vs. 67.71% (67.43 to 67.98); OR 1.02 (1.00 to 1.03)) and increased rate of referral with completed biopsy (3.89% (3.79 to 4.00) vs. 3.53% (3.42 to 3.65); OR 1.10 (1.05 to 1.15)). The main limitations of this analysis are that only the baseline results are presented, and there was an imbalance in invitations between the study arms., Conclusions: In this study, we observed that a real-life RHP of primary HPV-based screening was acceptable and effective when evaluated against cytology-based screening, as indicated by comparable participation, referral, and detection rates., Trial Registration: ClinicalTrials.gov NCT01511328., Competing Interests: The authors have declared that no competing interests exist.

We assessed the quality of human papillomavirus (HPV) sequences in GenBank by analyzing the possible presence of chimeras, "wrong-assembled" contigs and errors in taxonomy using an open-source script (HPVChimera&#95;Gb) that compared 25 638 HPV-related nucleotide sequences in GenBank with the 221 numbered HPV types and another 220 complete HPV sequences. There were 110 sequences with taxonomy/naming errors (sequences reported as another HPV type than the one they corresponded to) and 1318 possibly chimeric sequences. Manual analysis found plausible explanations for most of them (e.g. sequence covering an integration site) but 114 sequences appeared to be chimeras (96/114 were already flagged as "unverified" by GenBank) and 13 had taxonomy/naming errors. When comparing all correct HPV sequences in GenBank, there appeared to exist about 800 unique putative HPV types. Systematic and regular work towards eliminating chimeric sequences and taxonomy/naming errors could increase the quality and order in HPV research., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

The elimination of cervical cancer rests on high efficacy of human papillomavirus (HPV) vaccines. The HPV type distribution among cases of invasive cervical cancer (ICC) is used to make predictions about the impact of eliminating different types of HPV, but accumulating evidence of differences in age-specific cancer incidence by HPV type exists. We used one of the largest population-based series of HPV genotyping of ICCs (n = 2,850; Sweden, 2002-2011) to estimate age-specific ICC incidence by HPV type and obtain estimates of the cancer-protective impact of the removal of different HPV types. In the base case, the age-specific ICC incidence had 2 peaks, and the standardized lifetime risk (SLTR, the lifetime number of cases per birth cohort of 100,000 females) for HPV-positive ICC was 651 per 100,000 female births. In the absence of vaccine types HPV 16 and HPV 18, the SLTR for ICC was reduced to 157 per 100,000 female births (24% of HPV-positive SLTR). Elimination of all 9 types that can currently be vaccinated against reduced the remaining SLTR to 47 per 100,000 female births (7%), the remaining ICC incidence only slowly increasing with age. In conclusion, after elimination of vaccine-protected HPV types, very few cases of ICC will be left, especially among fertile, reproductive-age women., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.)

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., (© 2019 UICC.)

Introduction. Cervical cancer is caused by human papillomavirus (HPV), but some cases may test HPV-negative. We previously tested 2850 Swedish cases and found that 394/2850 (13.8 %) cases tested HPV DNA-negative by PCR. Sequencing is the most thorough method to assess HPV status. Aim . We wished to assess whether deep sequencing might detect HPV sequences among these HPV-negative cervical cancer specimens, and to increase the likelihood of detecting transcriptionally active infections. Methodology. Out of the 2850 cancer cases, we sequenced a random sample of 92 HPV PCR-negative cervical cancers and 34 HPV PCR-positive cervical cancers. Four pools of blank blocks were sequenced as negative controls. To enrich for mRNA - a hallmark of active viral infection - the samples were extracted, reverse-transcribed, rRNA-depleted and then sequenced using the NovaSeq 6000 system (Illumina, USA). High-quality reads were aligned to the human genome and non-human reads were queried against HPV proteins. Results. We obtained a median of 23 million paired reads per sample. HPV was detected in 31/34 HPV PCR-positive cases. Among cases negative for HPV by PCR, 48/92 (52.2 %) contained HPV sequences, with HPV33 being the most commonly detected type among these (14/48 cases, 29.2 %). Comparison of the ratio of exon and intron sequences found that the sequenced material contained both DNA and RNA. Splice junctions were detected in 12 cases. Conclusion. Apparently, some cervical cancers contain HPV that is difficult to detect by PCR. Sequencing may be a helpful tool for additional quality assurance for HPV testing methods.

Background: High-risk human papillomavirus (hrHPV) infection is established as the major cause of invasive cervical cancer (ICC). However, whether hrHPV status in the tumor is associated with subsequent prognosis of ICC is controversial. We aim to evaluate the association between tumor hrHPV status and ICC prognosis using national registers and comprehensive human papillomavirus (HPV) genotyping., Methods and Findings: In this nationwide population-based cohort study, we identified all ICC diagnosed in Sweden during the years 2002-2011 (4,254 confirmed cases), requested all archival formalin-fixed paraffin-embedded blocks, and performed HPV genotyping. Twenty out of 25 pathology biobanks agreed to the study, yielding a total of 2,845 confirmed cases with valid HPV results. Cases were prospectively followed up from date of cancer diagnosis to 31 December 2015, migration from Sweden, or death, whichever occurred first. The main exposure was tumor hrHPV status classified as hrHPV-positive and hrHPV-negative. The primary outcome was all-cause mortality by 31 December 2015. Five-year relative survival ratios (RSRs) were calculated, and excess hazard ratios (EHRs) with 95% confidence intervals (CIs) were estimated using Poisson regression, adjusting for education, time since cancer diagnosis, and clinical factors including age at cancer diagnosis and International Federation of Gynecology and Obstetrics (FIGO) stage. Of the 2,845 included cases, hrHPV was detected in 2,293 (80.6%), and we observed 1,131 (39.8%) deaths during an average of 6.2 years follow-up. The majority of ICC cases were diagnosed at age 30-59 years (57.5%) and classified as stage IB (40.7%). hrHPV positivity was significantly associated with screen-detected tumors, young age, high education level, and early stage at diagnosis (p < 0.001). The 5-year RSR compared to the general female population was 0.74 (95% CI 0.72-0.76) for hrHPV-positive cases and 0.54 (95% CI 0.50-0.59) for hrHPV-negative cases, yielding a crude EHR of 0.45 (95% CI 0.38-0.52) and an adjusted EHR of 0.61 (95% CI 0.52-0.71). Risk of all-cause mortality as measured by EHR was consistently and statistically significantly lower for cases with hrHPV-positive tumors for each age group above 29 years and each FIGO stage above IA. The difference in prognosis by hrHPV status was highly robust, regardless of the clinical, histological, and educational characteristics of the cases. The main limitation was that, except for education, we were not able to adjust for lifestyle factors or other unmeasured confounders., Conclusions: In this study, women with hrHPV-positive cervical tumors had a substantially better prognosis than women with hrHPV-negative tumors. hrHPV appears to be a biomarker for better prognosis in cervical cancer independent of age, FIGO stage, and histological type, extending information from already established prognostic factors. The underlying biological mechanisms relating lack of detectable tumor hrHPV to considerably worse prognosis are not known and should be further investigated., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: JD has obtained grants to his institution from Roche and Genomica for research on HPV tests. BA is supported by an unrestricted grant from the Swedish Strategic Research Fund, and BA is a member of the National Board of Health and Welfare Expert's Group in 2015 about HPV-based organised cervical screening. The other authors have no conflict of interest to declare.

Knowledge of determinants of anal human papillomavirus (HPV) infections among men is still limited as most of the studies are focused on high-risk populations and geographically narrowed. Such knowledge obtained in different populations is essential for better understanding of HPV natural history, transmission dynamics, and its role in the development and prevention of anogenital malignancies in different regions. Here we tested anal canal swab samples from 359 Russian heterosexual (323 human immunodeficiency virus [HIV]-negative and 27 HIV-positive, aged 18-67 years) men attending a sexually transmitted infection clinic 36 HPV types using a proficient Luminex assay. HPV-positivity in anal samples was common for 332 HIV-negative heterosexual men for overall HPV (15.7%, n = 52), oncogenic HPV (9.6%, n = 32), nononcogenic HPV (8.1%, n = 27), and multiple HPV infections (4.5%, n = 14). The most common anal HPV types were HPV16 (5.7%), HPV45, and HPV51 (1.8% each), HPV66, and HPV87 (1.8% each). No association was found with the number of lifetime sexual partners, age of participants at the time of the study, or their sexual debut. Although anal HPV positivity was more common among HIV-positive men, the current study provides additional evidence that anal HPV can be frequently detected in heterosexual HIV-negative men favoring further studies on transmission routes to discriminate between contamination and true HPV infection., (© 2018 Wiley Periodicals, Inc.)

The International Human Papillomavirus (HPV) Reference Center supports quality and order in HPV research and diagnostics. Notably, the center assigns HPV type numbers to novel HPV types, maintains a reference clone repository, and issues international proficiency panels for HPV genotyping. The established HPV types, currently up to HPV225, belong to 5 different genera: alpha (65 types), beta (54 types), gamma (98 types), mu (3 types) and nu (1 type). Since 2014, 23 novel types have been established, 82.6% of which belong to the gamma genus. Reference clones have been provided to 44 different research laboratories and the global proficiency program for HPV genotyping has seen an increasing participation (currently 146 laboratories) and complete proficiency has increased over time (from 26% to 59% of datasets). In summary, an increasing complexity of the HPVs requires international efforts to support a recognized quality and order among HPV types., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: The Swedish National Cervical Screening Registry collects and evaluates comprehensive, nationwide health data to optimise organised cervical cancer prevention. Since all cervical cancer specimens are saved in biobanks, population-based data from the specimens should be available for analysis and linkage with other health information., Methods: We identified all cervical cancers diagnosed in Sweden during 2002-2011 (4254 confirmed cases) and requested the tissue blocks to retrieve human papillomavirus (HPV) genotype data using general primer PCR with Luminex genotyping and real-time PCR targeting the E6/E7 regions of HPV16/18., Results: We obtained blocks from 2932/4254 (69%) of cases. Valid HPV genotyping data was retrieved for 2850 cases (97%). The most common type was HPV16 (60%), followed by HPV18 (19%), HPV45 (7%), HPV31 (3%), HPV33 (2%), HPV52 (2%), HPV39 (1%), HPV70 (1%), HPV56 (1%), HPV35 (1%), HPV58 (1%) and HPV59 (1%). Ninety-six percent of all HPV-positive cases had a single infection. Eighty-nine cases were HPV-positive only when testing for the HPV16/18-E6/E7 region., Conclusions: We present one of the largest series of HPV-genotyped cervical cancers to date. The systematic collection of cervical cancer HPV genotyping data by the screening registry will facilitate prevention and monitoring of HPV type-specific disease burden.

Background: Accurate and internationally comparable human papillomavirus (HPV) DNA detection and typing services are essential for HPV vaccine research and surveillance., Objectives: This study assessed the proficiency of different HPV typing services offered routinely in laboratories worldwide., Study Design: The HPV Laboratory Network (LabNet) has designed international proficiency panels that can be regularly issued. The HPV genotyping proficiency panels of 2013 and 2014 contained 43 and 41 coded samples, respectively, composed of purified plasmids of sixteen HPV types (HPV 6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68a and 68b) and 3 extraction controls. Proficient typing was defined as detection in both single and multiple infections of 50 International Units of HPV 16 and HPV 18 and 500 genome equivalents for the other 14 HPV types, with at least 97% specificity., Results: Ninety-six laboratories submitted 136 datasets in 2013 and 121 laboratories submitted 148 datasets in 2014. Thirty-four different HPV genotyping assays were used, notably Linear Array, HPV Direct Flow-chip, GenoFlow HPV array, Anyplex HPV 28, Inno-LiPa, and PGMY-CHUV assays. A trend towards increased sensitivity and specificity was observed. In 2013, 59 data sets (44%) were 100% proficient compared to 86 data sets (59%) in 2014. This is a definite improvement compared to the first proficiency panel, issued in 2008, when only 19 data sets (26%) were fully proficient., Conclusion: The regularly issued global proficiency program has documented an ongoing worldwide improvement in comparability and reliability of HPV genotyping services., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Condylomata acuminata is caused by human papillomavirus (HPV). PCR with consensus primers will typically detect HPV in >96% of condylomata. Metagenomic sequencing has found that some "HPV-negative" condylomata do indeed contain HPV. We wished to perform a renewed evaluation of the "HPV-negative" condylomata using deeper metagenomics sequencing. Sequencing of whole genome amplified DNA from 40 apparently "HPV-negative" condylomata detected HPV in 37/40 specimens. We found 75 different HPV types, out of which 43 represented novel putative HPV types. Three types were cloned and established as HPV types 200, 201 and 202. Molluscum contagiosum virus was detected in 24 of the 40 samples. In summary, deep sequencing enables detection of HPV in almost all condylomata. "HPV-negative" condylomata might largely be explained by clinical misdiagnosis or the presence of viral variants, distantly related HPV types and/or low viral loads., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Non-melanoma skin cancers commonly contain Human Papillomavirus (HPV), but the types found have varied depending on the polymerase chain reaction (PCR) primer systems used. Whole genome amplified DNA (not amplified by any specific PCR primers) from 91 skin lesions [41 squamous cell skin carcinomas (SCCs), 8 keratoacanthomas, 22 actinic keratoses, 3 basal cell carcinomas and 17 SCCs in situ] were sequenced. All samples were sequenced both at 160 Mb and 1.8 Gb sequencing depth per sample. The sequences from 10 different HPVs in 47/91 specimens were found. Sequences represented four established HPV types (HPV types 16, 22, 120, 124), two previously known putative types (present in GenBank) and four previously unknown HPV sequences (new putative types). The most commonly detected virus was cloned, sequenced and designated as HPV197. Type-specific real-time PCR detected HPV197 in 34/91 specimens. For comparison, a pool of the same samples after general primer PCR amplification was also sequenced. This revealed 40 different HPVs, but only two HPV types were detected both with sequencing without prior PCR and with sequencing PCR amplicons, suggesting that sequencing without prior PCR gives a more unbiased representation of the HPVs present. In summary, it was found that HPV can be sequenced from most skin disease specimens and HPV197 appeared to be the most commonly present virus., (© 2014 UICC.)

Established Human Papillomavirus (HPV) types, up to HPV202, belong to 49 species in five genera. International standardization in classification and quality standards for HPV type designation and detection is ensured by the International HPV Reference Center. The center i) receives clones of potentially novel HPV types, re-clones and re-sequences them. If confirmed, an HPV type number is assigned and posted on www.hpvcenter.se. ii) distributes reference clone samples, for academic research, under Material Transfer Agreements agreed with the originator. iii) provides preliminary checking of whether new sequences represent novel types iv) issues international proficiency panels for HPV genotyping. The rate of HPV type discovery is increasing, probably because of metagenomic sequencing. γ-genus today contains 79HPV types and 27 species, surpassing ∝ and β genera with 65 and 51HPV types, respectively. Regular issuing of proficiency panels based on HPV reference clones has resulted in global improvement of HPV genotyping services., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Human papillomavirus (HPV) infections result in a significant burden of low-grade cervical lesions. Between 1997 and 2000, our randomized trial of primary HPV screening enrolled 12,527 women participating in population-based screening. Women between 32 and 38 years of age (median: 34, interquartile range: 33-37) were randomized to HPV and cytology double testing (intervention arm, n = 6,257 enrolled, n = 5,888 followed-up) or to cytology, with samples frozen for future HPV testing (control arm, n = 6,270 enrolled, n = 5,795 followed-up). We estimated the HPV type-specific, long-term absolute risks (AR), and population attributable proportions (PAR) for cytological diagnoses of atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) and for histopathologically diagnosed cervical intraepithelial neoplasia grade 1 (CIN1). The women were followed using comprehensive, nationwide register-based follow-up. During a mean follow-up time of 11.07 years, 886 ASCUS and LSIL lesions were detected, 448 in the intervention arm and 438 in the control arm. Poisson regression estimated the incidence rate ratios (IRRs) of low-grade lesions by HPV type. The IRRs were strongly dependent on follow-up time. The IRRs for ASCUS/LSIL associated with high-risk HPV positivity were 18.6 (95% CI: 14.9-23.4) during the first screening round, 4.1 (95% CI: 2.8-6.2) during the second, 2.6 (95% CI: 1.7-4.1) during the third, and 1.1 (95% CI: 0.7-1.8) for >9 years of follow-up, with similar declines seen for the individual types. Type 16 contributed consistently to the greatest proportion of ASCUS, LSIL, and CIN1 risk in the population (first screening round PAR: ASCUS: 15.5% (95% CI: 9.7-21.9), LSIL: 14.7% (95% CI: 8.0-20.9), and CIN1: 13.4% (95% CI: 3.2-22.5)), followed by type 31 [8.4% (95% CI: 4.2-12.5) for ASCUS to 17.3% (95% CI: 6.8-26.6) for CIN1]. In summary, most ASCUS/LSIL lesions associated with HPV infection are caused by new HPV infections and most lesions are found during the first screening round., (© 2014 UICC.)

Accurate and internationally comparable human papillomavirus (HPV) DNA genotyping is essential for HPV vaccine research and for HPV surveillance. The HPV Laboratory Network (LabNet) has designed international proficiency studies that can be issued regularly and in a reproducible manner. The 2011 HPV genotyping proficiency panel contained 43 coded samples composed of purified plasmids of 16 HPV types (HPV6, -11, -16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, -68a, and -68b) and 3 extraction controls. Tests that detected 50 IU of HPV16 and HPV18 and 500 genome equivalents for the other 14 HPV types in both single and multiple infections were considered proficient. Ninety-six laboratories worldwide submitted 134 data sets. Twenty-five different HPV genotyping assay methods were used, including the Linear Array, line blot/INNO-LiPA, PapilloCheck, and PCR Luminex assays. The major oncogenic HPV types, HPV16 and HPV18, were proficiently detected in 97.0% (113/116) and 87.0% (103/118) of the data sets, respectively. In 2011, 51 data sets (39%) were 100% proficient for the detection of at least one HPV type, and 37 data sets (28%) were proficient for all 16 HPV types; this was an improvement over the panel results from the 2008 and 2010 studies, when <25 data sets (23% and 19% for 2008 and 2010, respectively) were fully proficient. The improvement was also evident for the 54 laboratories that had also participated in the previous proficiency studies. In conclusion, a continuing global proficiency program has documented worldwide improvement in the comparability and reliability of HPV genotyping assay performances.

Objectives: To assess whether the increased sensitivity of screening for human papillomavirus (HPV) may represent overdiagnosis and to compare the long term duration of protective effect against cervical intraepithelial neoplasia grade 2 or worse (CIN2+) in HPV based and cytology based screening., Design: 13 year follow-up of the Swedescreen randomised controlled trial of primary HPV screening., Setting: Organised cervical screening programme in Sweden., Participants: 12,527 women aged 32-38 attending organised screening were enrolled and randomised to HPV and cytology double testing (intervention arm, n=6257) or to cytology only, with samples frozen for future HPV testing (control arm, n=6270)., Main Outcome Measures: Cumulative incidence of CIN2+ and CIN3+ (Kaplan Meier curves). Longitudinal test characteristics were calculated for cytology only, HPV testing only, and cytology and HPV testing combined, adjusting for censoring., Results: The increased detection of CIN2+ in the intervention arm decreased over time. After six years, the cumulative incidence of CIN3+ was similar in both trial arms, and after 11 years the cumulative incidence of CIN2+ became similar in both arms. The longitudinal sensitivity of cytology for CIN2+ in the control arm at three years was similar to the sensitivity of HPV testing in the intervention arm at five years of follow-up: 85.94% (95% confidence interval 76.85% to 91.84%) v 86.40% (79.21% to 91.37%). The sensitivity of HPV screening for CIN3+after five years was 89.34% (80.10% to 94.58%) and for cytology after three years was 92.02% (80.59% to 96.97%)., Conclusions: Over long term follow-up, the cumulative incidence of CIN2+ was the same for HPV screening and for cytology, implying that the increased sensitivity of HPV screening for CIN2+ reflects earlier detection rather than overdiagnosis. The low long term risks of CIN3+ among women who tested negative in HPV screening, support screening intervals of five years for such women., Trial Registration: Clinicaltrials.gov NCT00479375.

Background: Human papillomavirus (HPV) genotyping using next generation sequencing (NGS) could be useful to study the HPV variant-specific epidemiology, including monitoring for possible emergence of new HPV variants after introduction of HPV vaccination programs., Objectives: We wished to design and validate a method for rapid HPV detection, typing and sequencing in clinical samples., Study Design: Plasmids of 15 different HPV types were mixed and serially diluted in human DNA in concentrations ranging from 1 to 100 copies per sample, amplified using the HPV general PCR primer pair PGMY and sequenced using 454 technology. Sixty cervical samples were tested both with the NGS-based method and with a comparison method based on genotyping using type-specific probes bound to fluorescent beads (Luminex). Thirty-three clinical samples were repeat tested using NGS to evaluate reproducibility., Results: The NGS-based method correctly identified all 15 mixed HPV types when present in 100 copies/sample and 13/15 types when present in 10 copies/sample. For 36/60 cervical samples genotyping results using NGS and Luminex were identical. For 12/60 samples the NGS method was more sensitive than the Luminex test and most of the remaining discrepancies could be explained by the different type coverage of the assays. Reproducibility testing found complete or partial concordance in 30/33 samples., Conclusions: NGS provides a sensitive and accurate method for genotyping of HPV. The fact that also the amplimer sequence is obtained could be important for studying the epidemiology of viral variants and monitoring of HPV vaccination., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Accurate and internationally comparable human papillomavirus (HPV) DNA genotyping is essential both for evaluation of HPV vaccines and for effective monitoring and implementation of vaccination programs. The World Health Organization (WHO) HPV Laboratory Network (LabNet) regularly issues international proficiency studies. The 2010 HPV genotyping proficiency panel for HPV vaccinology contained 43 coded samples composed of purified plasmids of 16 HPV types (HPV types 6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68a and 68b) and 3 coded extraction controls. Proficient typing was defined as detection in both single and multiple infections of 50 international units (IU) of HPV type 16 (HPV-16) and HPV-18 DNA and 500 genome equivalents (GE) for the other 14 HPV types. Ninety-eight laboratories worldwide submitted a total of 132 data sets. Twenty-four different HPV genotyping assay methods were used, with Linear Array being the most commonly used. Other major assays used were a line blot assay (Inno-LiPa), CLART, type-specific real-time PCR, PCR Luminex, and different microarray assays. Altogether, 72 data sets were proficient for detection of more than 1 type, and only 26 data sets proficiently detected all 16 HPV types. The major oncogenic HPV types, 16 and 18, were proficiently detected in 95.0% (114/120) and 87.0% (94/108) of data sets, respectively. Forty-six data sets reported multiple false-positive results and were considered nonproficient. A trend toward increased sensitivity of assays was seen for the 41 laboratories that participated in both 2008 and 2010. In conclusion, continued global proficiency studies will be required for establishing comparable and reliable HPV genotyping services for vaccinology worldwide.

Internationally comparable quality assurance of Human Papillomavirus (HPV) DNA detection and typing methods is essential for evaluation of HPV vaccines and effective monitoring and implementation of HPV vaccination programs. Therefore, the World Health Organization (WHO) HPV Laboratory Network (LabNet) designed an international proficiency study. Following announcement at the WHO website, the responding laboratories performed HPV typing using one or more of their usual assays on 43 coded samples composed of titration series of purified plasmids of 16 HPV types (HPV6, -11, -16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, and -68). Detection of at least 50 IU of HPV16 or HPV18 DNA and of 500 genome equivalents (GE) of the other 14 HPV types (in samples with single and multiple HPV types) was considered proficient. Fifty-four laboratories worldwide submitted a total of 84 data sets. More than 21 HPV-genotyping assays were used. Commonly used methods were Linear Array, Lineblot, InnoLiPa, Clinical Array, type-specific real-time PCR, PCR-Luminex and microarray assays. The major oncogenic HPV types (HPV16 and -18) were detected in 89.7% (70/78) and 92.2% (71/77) of the data sets, respectively. HPV types 56, 59, and 68 were the least commonly detected types (in less than 80% of the data sets). Twenty-eight data sets reported multiple false-positive results and were considered nonproficient. In conclusion, we found that international proficiency studies, traceable to international standards, allow standardized quality assurance for different HPV-typing assays and enable the comparison of data generated from different laboratories worldwide.

Objective: The Guanacaste study ("Guanacaste Project," or GP), was designed to investigate the role of human papillomavirus (HPV) infection and its cofactors in the development of cervical neoplasia and to evaluate new cervical cancer screening technologies. The follow-up phase of the GP was designed to study why a small proportion of women infected with HPV develop cervical intraepithelial neoplasia grade 2 (CIN 2), CIN 3, or cancer (these three together are globally referred to as > or = CIN 2, that is, CIN 2 or worse). The purpose of this article is to describe this prospective study in detail and to present the preliminary findings regarding the incidence of cervical neoplasia., Methods: A cohort of 10 049 randomly selected women from 18 to 97 years old from Guanacaste, a province in northwestern Costa Rica, was intensively screened in 1993-1994 and then followed up for seven years after being enrolled. A questionnaire for demographic and risk factors was administered, and a pelvic examination was performed on sexually active women at each follow-up visit in order to obtain samples for screening tests and for research purposes. The final diagnosis given at the end of the enrollment phase categorized women into several groups according to the perceived risk of their developing either high-grade precursors of cancer or cancer. These groups were followed up at different intervals according to the risk of developing > or = CIN 2. The most active follow-up (every 6-12 months) was concentrated on the women most likely to develop >or = CIN 2, based on cytology (n = 492). The remainder of the cohort was followed either annually (n = 2 574) or after five to seven years of passive follow-up (n = 3 926). All women with possibly severe lesions detected by any technique were referred to colposcopy for further evaluation and treatment, and they were also censored from the study. Lesions >or = CIN 2 served as both the censoring outcome and our surrogate for cancer risk., Results: Participation during follow-up was high (near 90%). Suspected > or = CIN 2 by any screening technique censored 4.6% of women. Most of the women censored because of suspected > or = CIN 2 came from the large group perceived at entry as being at low risk of developing > or = CIN 2, but the greatest rates of progression to > or = CIN 2 were observed among women perceived at entry to be at highest risk of > or = CIN 2, based on their cytology, virology, or sexual behavior., Conclusions: The GP is the largest population-based longitudinal cohort for the study of HPV and cervical neoplasia in the world, and its results will hopefully let us soon plan future worldwide prevention strategies. Research projects such as this one require the long-term commitment of a large multidisciplinary team and ample financial resources. The intensive effort and expertise applied in all aspects of this study were key factors in its success as a model of cooperative, interdisciplinary cancer research in Latin America. Quality control played an important role at all times during the study and made it possible to adapt new diagnostic and screening technology to Guanacaste. The systematic follow-up of a population-based group of close to 10 000 women in Guanacaste should permit careful, time-dependent evaluation of factors postulated to be linked to the development of cervical cancer as well as the evaluation of clinical markers of disease progression. The study results that have already been published have validated sensitive screening techniques and have also promoted the use of more affordable screening techniques in resource-poor, developing countries. The GP has also contributed to building knowledge for the search for vaccines against HPV as part of the effort to develop an effective tool to reduce the incidence and mortality of cervical cancer worldwide.

Increased understanding of human papillomavirus (HPV) infection as the central cause of cervical cancer has permitted the development of improved screening techniques. To evaluate their usefulness, we evaluated the performance of multiple screening methods concurrently in a large population-based cohort of >8500 nonvirginal women without hysterectomies, whom we followed prospectively in a high-risk region of Latin America. Using Youden's index as a measure of the trade-off between sensitivity and specificity, we estimated the performances of a visual screening method (cervicography), conventional cytology, liquid-based cytology (ThinPrep), and DNA testing for 13 oncogenic HPV types. The reference standard of disease was neoplasia > or = cervical intraepithelial neoplasia grade 3 (CIN 3), defined as histologically confirmed CIN 3 detected within 2 years of enrollment (n=90) or invasive cancer detected within 7 years (n=20). We analyzed each technique alone and in paired combinations (n=112 possible strategies), and evaluated the significance of differences between strategies using a paired Z test that equally weighted sensitivity and specificity. As a single test, either liquid-based cytology or HPV DNA testing was significantly more accurate than conventional cytology or cervicography. Paired tests incorporating either liquid-based cytology or HPV DNA testing were not substantially more accurate than either of those two test strategies alone. However, a possibly useful synergy was observed between the conventional smear and cervicography. Consideration of age or behavioral risk profiles did not alter any of these conclusions. Overall, we conclude that highly accurate screening for cervical cancer and CIN 3 is now technically feasible. The remaining vital issue is to extend improved cervical cancer prevention programs to resource-poor regions.

Isotype-specific serum antibody responses against human papillomavirus (HPV) type 16 were evaluated by use of cross-sectional, prospective, and population-based seroepidemiologic studies. IgG1 and IgA were the most abundant isotypes. No sample contained IgG2, and <25 samples contained IgG3 or IgM. Total IgG, IgA, and IgG1 were HPV type specific and were associated with HPV-16 DNA (odds ratios [ORs], 5.4, 5.0, and 5.9, respectively; P<.001) but not with other HPV DNA (ORs, 1.2, 1.2, and 0.8, respectively; P value was not significant). Total IgG and IgG1 were strongly associated with number of lifetime sex partners (P<.001); IgA was only associated with number of recent sex partners and lifetime sex partners among younger women. Total IgG, IgG1, and IgA were associated with cervical intraepithelial neoplasia type III and also predicted risk of future cervical neoplasia. IgG and IgG1 appeared to mark lifetime cumulative exposure, whereas IgA may mark recent or ongoing infection.

Human papillomavirus (HPV) types 16 and 18 are the major risk factors for cervical carcinoma, whereas HPV types 6 and 11 cause benign genital lesions. We wanted to study the joint effect of simultaneous infections with the oncogenic and non-oncogenic HPV types on risk of subsequent development of cervical carcinoma. A cohort of 530,000 women who had donated blood samples to Nordic serum banks between 1973 and 1994 was followed up by linkage to national cancer registries. We identified 182 prospective cases with invasive cervical carcinoma and selected 538 matched controls at random. HPV 6, 11, 16, 18 and 33 seropositivity was used as a marker for the different HPV infections, and seropositivity for Chlamydia trachomatis and cotinine were used as markers for risk-taking sexual behavior and smoking respectively. The adjusted odds ratio (OR) of cervical squamous-cell carcinoma (SCC) was 2.2 for HPV6/11 among HPV16 seronegatives and 5.5 for HPV16 among HPV6/11 seronegatives. Assuming multiplicative joint effect, the expected OR for seropositivity to both HPV6/11 and HPV16 would have been 12, but the observed OR was 1.0. The antagonistic interaction was statistically significant (p = 0.001) and present also under deterministic considerations of possible misclassification bias. Antagonistic interactions were also detected for combinations of HPV16 and HPV18 and of HPV16 and HPV33. The results are in line with the concept that HPV-specific immunity protects against SCC and support primary prevention of SCC by vaccination against the HPVs.

The importance and natural history of HPV infections in childhood is incompletely understood. We performed a survey for presence of serum antibodies to HPV capsids among 1031 children aged 0 to 13 years, resident in Stockholm, Sweden. The HPV seroprevalence among these children was 3.0% for HPV16, 0.6% for HPV18 and 2.7% for HPV33. By comparison, among simultaneously analyzed positive control panels comprising women with CIN or healthy women with type-specific cervical HPV DNA, seroprevalence of HPV 16, 18 and 33 was 69%, 58% and 63% respectively. The results suggest that HPV infection in childhood is not common.

To assess long-term trends in the prevalence of oncogenic human papillomavirus (HPV) infection, we performed a cross-sectional serosurvey of the seroprevalence of the major oncogenic HPV type, HPV16, among 3,512 pregnant women undergoing population-based serological screening at the first trimester of pregnancy in the same catchment area in Stockholm, Sweden, during 1969, 1983 or 1989. The overall HPV16 seroprevalence rates were 16% in 1969, 22% in 1983 and 21% in 1989. Seroprevalence was significantly increased, comparing both 1969 vs. 1983 (p = 0.0005) and 1969 vs. 1989 (p = 0.008). By comparison, the previously reported herpes simplex 2 (HSV-2) seroprevalence in the same women increased from 17% in 1969 to 32% in 1983 and 33% in 1989, whereas the seroprevalence rates of HSV-1 were the same (69% in 1969, 63% in 1983 and 68% in 1989). Odds ratios for HPV 16-positive women to also be HSV-2-positive were 1.8 in 1969 (p < 0.005), 1.1 in 1983 (p = NS) and 1.0 in 1989. Our results suggest that both HSV-2 and HPV16 became more generally spread in the Swedish population between 1969 and 1983 but that the spread has been stable during the 1980s.

Serum samples from 47 men with current condylomas, 32 men with a history of condylomas and from 205 men with no history of genital wart disease, who were attending sexually transmitted disease (STD) clinics at two different hospitals in Stockholm, were analyzed for the presence of immunoglobulin G (IgG) and A (IgA) antibodies to capsids of human papillomavirus types 6 and 11. IgG to HPV type 6 was found among 35% of patients with a history of condylomas compared to 10% of controls (p = 0.0003), but only among 27% of patients with current condylomas. Antibodies to HPV 6 and to HPV 11 showed a very limited correlation, suggesting that the antibodies are HPV-type restricted. The results strengthen conclusions from a previous serological study indicating that IgG antibodies against HPV 6 develop late during condylomatous disease and mostly reflect previous exposure to the virus.

Serological markers of squamous intraepithelial lesions (SILs), the precursors of cervical cancer, have not been studied extensively. To screen for antibody responses that might be associated with SILs, we measured IgG and/or IgA to nine antigens based on papillomaviruses, the infectious cause of SIL and cervical cancer, using an ELISA format. Cases were 59 women with low grade SIL (LSIL) and 38 with high grade SIL (HSIL). Controls were 50 women chosen to minimize the possibility that they ever had SILs [individuals who had no history of SIL and repeatedly tested negative for cervical human papillomavirus (HPV) DNA], frequency age-matched to cases. The data showed that five antibodies had strong positive associations with SILs and that one was inversely related to SILs. By studying these antibodies in pairs, furthermore, we found that case-control differences were enhanced. In particular, the combination of IgG to an epitope in the E6 protein of HPV 16 (E6:10) and IgA to HPV 16 virus-like particles (VLPs) was detected in 53% of LSILs and 65% of HSILs but only 9% of controls. These same responses were both negative in just 6% of LSILs and zero HSILs, compared to 59% of controls. Notably, E6:10 IgG and HPV 16 VLP IgA were not correlated with each other, and the other antibody responses positively associated with SILs could be broken into two groups: those correlated with E610 IgG and those correlated with HPV 16 VLP IgA. Overall, the data suggest that several papillomavirus antibodies may be strongly related to SILs, and that they can be divided into at least two independent groups of humoral immune reactions.

A panel of 24 monoclonal antibodies (MAbs) was generated against human papillomavirus (HPV) types 16 and 18 L1 virus-like particles (VLPs). The MAbs were screened for reactivity to a variety of VLPs prepared from HPV-6, -11, -16, -18, -31, -33, -35, and -45, cottontail rabbit papillomavirus, bovine papillomavirus type 1, and a set of 35 overlapping 20-amino-acid peptides spanning the entire HPV-16 L1 gene. Type-specific linear and conformational surface epitopes were detected as well as several cross-reactive linear epitopes that showed various levels of cross-reactivity between different genital HPV and animal papillomavirus L1s. Most of the linear epitopes were mapped using synthetic peptides, and the epitopes were identified as being either surface or buried within the VLP as defined by the pattern of reactivity in ELISA using intact and disrupted VLP antigen. These MAbs may be useful reagents to help define neutralizing epitopes of HPV-16 and -18 when infectivity assays become available, and to define the regions of L1 that are exposed on the surface or buried within the assembled capsid.

A group of human papillomaviruses (HPV), in particular HPV type 16, are the major cause of anogenital dysplasias, which are precursors of anogenital cancer. The mode of transmission, extent of infectivity and natural history of infection are incompletely understood because methods to quantify shedding of viral particles have not been available. A two-site ELISA was developed to detect and quantify HPV-16 particles. Rabbits and guinea pigs were immunized with a series of peptides from the L1 and L2 capsid proteins of HPV-16. Among rabbit antipeptide sera tested for use as capture antibodies, only sera against one peptide bound detectable amounts of virus. Guinea pig antisera against several peptides were used as reporter antibodies to detect bound virus particles. If antisera against the same peptide were used both as capture antibody and reporter antibody, only intact particles were detected. Disrupted particles were quantified using antibodies against one L1 peptide as capture antibody and antibodies against other L1 peptides as reporter antibody. The lowest detectable amount of virus was 3 ng (0.06 micrograms/ml). There was no detectable cross-reaction with HPV type 6 or 11. The assay could be used both with cervical swabs in several common sample collection buffers and with surgical material solubilized in NP40-containing extraction buffers. Among 15 surgically removed condyloma acuminata, only 1 specimen was found to contain HPV-16 particles, at a concentration of 375 ng/ml (1.1 micrograms/specimen). Among 29 cervical swab samples from patients with koilocytotic atypia, 9 samples were found to contain virus. The results indicate that this assay is useful for large-scale studies on shedding of HPV particles.

Background: Anal epidermoid carcinoma is a relatively rare tumor, but its incidence has been increasing rapidly during the past few years. Genetic material from the major oncogenic types of human papillomavirus (HPV), types 16 and 18, has regularly been demonstrated in a substantial proportion of anal cancers, suggesting an etiologic role of HPV infection. Recently, serum antibodies against HPV type 16 capsids were shown to be a serologic measure of HPV16 infection., Purpose: We investigated whether serum antibodies against HPV16 capsids are associated with an increased risk of developing anal cancer., Methods: Serum samples from 64 patients (48 women and 16 men) with untreated anal epidermoid cancer and from 79 age- and sex-matched healthy blood donors were analyzed for the levels of serum immunoglobulin G (IgG) against capsids of HPV16 by the enzyme-linked immunosorbent assay. The levels of serum IgG against HPV type 6 and bovine papillomavirus (BPV) capsids, as well as against HPV16 peptide antigens, were also measured., Results: Whereas antibodies against HPV6 or BPV capsids were not significantly associated with anal cancer, the presence of IgG against HPV16 capsids exceeding the anti-BPV antibody levels was demonstrated among 55% (35 of 64) of the case patients but only among 4% (three of 79) of the control subjects (odds ratio [OR] = 30.4; 95% confidence interval [CI] = 8.4-161.5). Antibodies against HPV16 E2 and E7 peptides were also more common among case patients (OR = 12.8 and 95% CI = 5.4-31.5 for E2; OR = 3.0 and 95% CI = 1.4-6.7 for E7)., Conclusion: The results suggest that HPV16 capsid antibodies are serologic markers for anal cancer., Implication: Exposure to HPV16 or related viruses appears to be a major risk factor in the majority of anal cancers.

In a seroepidemiological study of incident cervical cancer, 94 cases and 188 population-based controls were used to evaluate the disease-association of IgG and IgA antibody responses against 6 human papillomavirus (HPV) type-16 antigens. Nine of the tested antibody responses were positively associated with cervical cancer, with odds ratios (ORs) ranging from 2.5 to 15.0. The antibody responses most strongly associated with cervical cancer were IgA against E6:10, an epitope derived from the carboxyterminal part of the HPV16 E6 [OR = 15.0, confidence intervals (CI) = 5.9-48.6], IgG against HPV16 virus-like particles (OR = 9.5, CI = 3.9-28.0) and IgG against the E1:19 epitope in the middle part of the E1 protein of HPV16 (OR = 7.7, C1 = 3.9-16.5). When the 3 serological assays that showed the strongest association with cervical cancer were combined, positivity for 2 assays was found among 52% of cases at an OR of 29.9. We conclude that antibody responses to several linear and conformational HPV epitopes are independently associated with cervical cancer and that combined analysis of several HPV antibody responses can result in better predictive values for HPV-associated cancer.

In order to provide a large-scale evaluation of the association with cervical cancer of antibodies against human papillomavirus (HPV) antigens, sera from 233 patients with primary, untreated cervical cancer and from 157 healthy age- and sex-matched blood donors were analyzed for IgG and IgA antibodies against HPV-derived peptide antigens and against bovine papillomavirus. Several serological responses were strongly associated with cervical cancer, notably the IgG response against the HPV 16 epitopes L1:13 (Relative risk [RR]: 5.3), E2:9 (RR: 2.9), and E7:5 (RR: 4.3), and the IgA response against an HPV 18 E2-derived antigen (245:18, RR: 3.1). HPV DNA in corresponding cervical tumors was analyzed by Southern blotting (SB) and polymerase chain reaction (PCR) in 47 patients. Sixty-six percent of the patients carried HPV DNA as determined by SB, 91% of patients analyzed by PCR. Neither the antibody responses, nor the presence of HPV DNA were significantly associated with the biological properties of the tumors.

The structure and antigenicity of the HPV-16 E6 and E7 oncoproteins was studied using a set of antisera against overlapping synthetic peptides. We report that antigenic, mobile regions of the native proteins, as defined by reactivity with antipeptide antisera, occur at the N-termini of both E6 and E7 proteins, corresponding to regions of known or suspected protein-protein interactions. The putative zinc finger domains were consistently non-reactive, despite computer predictions of relatively high antigenicity, suggesting that the proposed zinc finger regions are held in stable secondary structures that the peptides were not able to mimic. In E6, the linker region between the two zinc fingers was antigenic, indicating that the two zinc finger structures might be able to articulate relative to one another by a flexible linker region. The highly antigenic N-terminal region of HPV-16 E7 was also found to be antigenic in E7 of both HPV-11 and HPV-18, indicating that the E7 proteins of different HPV types have similar antigenic structures. The identification of antigenic regions of the E6 and E7 proteins should be therefore be useful in the design of site-directed antibodies against E6 and E7 for numerous HPV types.

The seroepidemiology of genital human papillomavirus (HPV) and incident cervical squamous intraepithelial lesions (SIL) was studied in subjects selected from a large cohort monitored for the development of SIL. Serum IgG and IgA responses to 10 epitopes derived from HPV were measured in 21 incident cases of SIL and 56 matched controls. Cases showed elevated antibody (i.e., IgG and/or IgA) seroprevalence to 245:16, a peptide antigen derived from the E2 open reading frame of HPV 16 (OR = 5.76; 95% CI: 1.24, 26.81). The type of HPV DNA detected in cervical lavage specimens had no effect on this relationship. Multivariate analysis also showed that IgG to 245:6, an analogous peptide derived from HPV 6, was negatively associated with SIL (OR = 0.12; 95% CI: 0.02, 0.77). No other antibody responses tested were associated with SIL. Furthermore, no antibody responses were positively associated with detection of HPV DNA in women without SIL. We conclude that incident SIL is positively associated with antibody to an epitope derived from the E2 region of HPV 16, and negatively associated with antibody to an analogous peptide derived from HPV 6. The seroepidemiology of incident SIL appears different from that of cervical HPV infection in the absence of SIL.

The epidemiology of cervical cancer indicates the presence of a sexually transmitted risk factor, attributable at least in part to infection with human papillomavirus (HPV) type 16 or 18. We performed a seroepidemiological study of HPV and cervical cancer in the counties of Västerbotten and Norrbotten in Northern Sweden, a low-risk area for cervical cancer. Sera from 94 cases of incident cervical cancer were matched against 188 age- and sex-matched controls derived from a population-based blood bank. IgG and IgA antibodies were measured against a panel of 12 antigens derived from HPV types 6, 11, 16, or 18, as well as against Herpes simplex virus type 1 and 2, Chlamydia trachomatis, cytomegalovirus, Epstein-Barr virus, and bovine papillomavirus. Significantly increased relative risks (RRs) were found for IgG to HPV 16- or 18-derived antigens from the L1 (RR = 3.1), E2 (RRs = 2.8 and 9.2), and E7 (RRs = 3.8 and 2.7) open reading frames and for IgA to HPV 16-derived antigens from the E2 (RR = 3.3) and E6 (RR = 2.7) open reading frames. The highest RR (9.2, confidence intervals 4.4-19.4) was associated with IgG to an HPV 18 E2 antigen. Antibodies against cytomegalovirus, Herpes simplex virus type 2, Epstein-Barr virus, or bovine papillomavirus were, on their own, not significantly associated with cervical cancer, but seropositivity against multiple infections was associated with a successively increased relative risk. An increased risk was also found for IgG to Chlamydia trachomatis (RR = 1.7, confidence interval = 1.0-2.7). The results indicate that several HPV antibodies are strongly associated with cervical cancer, providing further seroepidemiological support for an etiological role of HPV in cervical cancer.

Sera from 159 men attending the sexually transmitted disease clinic at Karolinska Hospital, Stockholm, Sweden, were analyzed for the presence of immunoglobulin A (IgA) and IgG antibodies to a panel of synthetic peptides derived from the E2, L1, and L2 regions of the human papillomavirus types 1 (HPV 1), 6, 8, 11, 16, 18, 31, and 33. The study subjects were divided into three groups: (i) asymptomatic men with no history of genital warts who served as controls, (ii) men with visible condylomata, and (iii) men who had previously been afflicted with condylomata. There were no significant differences in antibody titers for any of the HPV 6- or 11-derived peptides among patients with current condylomata and the controls. For the peptide from L1 of HPV 6, there was an increase in the IgG titers among men with previous condylomata compared with the titers for the controls (52% versus 27% seropositivity; P less than 0.05). Also, for the peptide from L2 of HPV 6, there was an increase in the IgG titers among men who had been afflicted with condylomata previously (P less than 0.05). Increased IgA antibody titers against an HPV 16-derived peptide and an HPV 18-derived peptide were also detected. For the peptides from L1 and L2 of HPV 6, the study was extended to an additional group of 127 males attending the sexually transmitted disease clinic at Huddinge Hospital in southern Stockholm. Again, significantly increased antibody levels were detected only for IgG and only among asymptomatic men with a history of condylomata (P < 0.01 for the L1 peptide and P < 0.05 for the L2 peptide). The results suggest that the IgG response against the late proteins of HPV 6 reflects mainly previous exposure to the virus rather than ongoing viral disease.

Certain types of human papillomavirus (HPV), notably HPV type 16, are associated with flat or inverted proliferative lesions of the cervix uteri that can progress to malignancy. As a first step towards the serological study of the epidemiology of HPV, we have synthesized the entire amino acid sequences of the 2 major viral capsid proteins of HPV type 16, L1 and L2, as a set of 66 synthetic 20-residue peptides with an overlap of 5 amino acids. The peptides were tested for reactivity with IgA, IgG and IgM antibodies in the sera of 30 patients with HPV-16-carrying cervical neoplasms. Both IgG and IgM antibody responses were detected, but most of the reactivity found was of the IgA class. The most immunoreactive peptides were further analyzed for reactivity with sera from 22 patients with parotid gland tumors and with sera from 38 healthy individuals. The L2-encoded protein contained only one major linear epitope, which was not specific for HPV-16-carrying neoplasms. In contrast, the L1-encoded protein contained several epitopes that were regularly immunoreactive with antibodies present in the sera of patients with HPV-16-carrying cervical neoplasms, but only rarely so in the sera of patients with other tumors or of healthy individuals.