Human papillomavirus: pathogenesis and immunity

The involvement of human papilloma virus (HPV) in the aetiology and progression of cervical intraepithelial neoplasia (CIN) is still unresolved. This study was designed to assess the immunological responses to HPV types in patients presenting with varying degrees of CIN and in control groups, using in vitro measures of cellular and humoral responses.Lymphocyte proliferation assays (LPA) were performed using peripheral blood mononuclear cells (PBM) and various papillomavirus (PV) antigens. Twenty -five per cent (23/92) of patients with CIN responded to antigens derived from purified BPV, HPV -1 or HPV -2 with or without detergent disruption. The responses correlated with a past history of skin warts rather than cervical abnormalities, and the percentage of responders was similar to that in laboratory personnel (30 %) and lower than that in a group with recalcitrant common warts (50 %). Antigens specific to HPV -16 and HPV -18, in the form of bacterially expressed fusion proteins derived by the transcription and translation of the E6 and E4 open reading frames (ORF), occasionally produced specific positive responses, provided contaminating E.coli B galactosidase sequences had been removed during purification. Responses were low and suggested that the numbers of memory T cells specific to PV antigens were low and at the lower limit of detection of LPA. An indirect ELISA was developed to detect circulating IgG to PV antigens in colposcopy patients. Fifty per cent of patients had antibodies to disrupted HPV -1, HPV -2 or both, suggesting that a predominantly type- specific response was being detected. No correlation of immune responses with a degree of dysplasia or the presence of koilocytes in cervical biopsies was noted, but a high incidence of forgotten or inapparent past infection with cutaneous HPV types was found.In situ hybridisation (ISH) methods using non -radioactively labelled, cloned probes and synthetic oligonucleotide probes were developed for use on paraffin sections. Synthetic probes allowed a quicker, less destructive hybridisation protocol, with the sensitivity of detection being (y) improved by an anti -biotin -immunogold conjugated immunoglobulins -silver enhancement (IGSS) detection system. Double staining of PV antigen and nucleic acid on the same section was achieved. Synthetic oligonucleotides offer an exciting new tool for diagnostic virology, worthy of exploitation in many systems.Implantation of human foreskin infected with HPV -11 was shown to provide an animal model, albeit technically difficult, in which HPV could be produced, but a more practical technique of productive HPV infection in vitro is still required if the biology and pathogenesis of HPV infections is to be clarified further

Host chemokine signature as a biomarker for the detection of pre-cancerous cervical lesions

Background The ability to distinguish which hrHPV infections predispose to significant disease is ever more pressing as a result of the increasing move to hrHPV testing for primary cervical screening. A risk-stratifier or “triage” of infection should ideally be objective and suitable for automation given the scale of screening. Results CCL2, CCL3, CCL4, CXCL1, CXCL8 and CXCL12 emerged as the strongest, candidate biomarkers to detect underlying disease [cervical intraepithelial neoplasia grade 2 or worse (CIN2+)]. For CIN2+, CCL2 had the highest area under the curve (AUC) of 0.722 with a specificity of 82%. A combined biomarker panel of six chemokines CCL2, CCL3, CCL4, CXCL1, CXCL8, and CXCL12 provides a sensitivity of 71% and specificity of 67%. Conclusion The present work demonstrates that the levels of five chemokine-proteins are indicative of underlying disease. We demonstrate technical feasibility and promising clinical performance of a chemokine-based biomarker panel, equivalent to that of other triage options. Further assessment in longitudinal series is now warranted. Methods A panel of 31 chemokines were investigated for expression in routinely taken archived and prospective cervical liquid based cytology (LBC) samples using Human Chemokine Proteomic Array kit. Nine chemokines were further validated using Procartaplex assay on the Luminex platform

Development of an in-house ELISA to detect anti-HPV16-L1 antibodies in serum and dried blood spots

Measuring anti-HPV antibody levels is important for surveillance of the immunological response to both natural infection and vaccination. Here, an ELISA test for measurement of HPV-16L1 antibodies was developed and validated in sera and dried blood spots. An in-house ELISA was developed for measuring anti-HPV-16L1 IgA and IgG levels. The assay was standardized against WHO international standard serum and validated on serum, dried blood spots and cervical liquid based cytology samples from women attending colposcopy clinics in Scotland. Antibody avidity index was also measured in serum samples. The average HPV 16-L1 specific IgG and IgA levels measured in sera, in women attending a routine colposcopy service were 7.3 units/ml and 8.1 units/ml respectively. Significant correlations between serum and dried blood spot eluates for both IgG and IgA were observed indicating that the latter serve as a credible proxy for antibody levels. Average IgG Avidity Index was 35% (95% CI 25%-45%) suggesting previous, historical challenge with natural infection. This ELISA has potential for use in epidemiological and field studies of antibody prevalence and if coupled with avidity measurement may be of use in individual case monitoring of vaccine responses and failures

Persistent high risk HPV infection associated with development of cervical neoplasia in a prospective population study

Aims: To monitor the association between the course of high risk human papillomavirus (HR-HPV) infection and the development of cervical neoplasia over time, from a baseline of normal cervical cytology. Methods: This paper presents the follow up data from a previous cross sectional analysis. Women from a screening population who had normal cytology and who were HR-HPV positive were recalled after two to three years for cytology and HPV genotyping. The development of cervical neoplasia at follow up was related to the course of HPV infection (clearance, persistence, or sequential infection) and the presence of single or multiple HPV infections at baseline. A comparator control group of women who were HPV and cytologically negative at baseline were selected from the same population. Results: Twelve cases of dyskaryosis were found in women who were HPV positive at baseline; four were high grade. Only three cases of low grade dyskaryosis were found in the control group. Women with type specific persistent infections were significantly more likely to develop cervical neoplasia than women who cleared the infection (p = 0.0001) or were sequentially infected with different types (p = 0.001). Women with multiple HPV infections at baseline were no more likely to develop cervical dyskaryosis than those with a single infection. Conclusions: Type specific persistent HR-HPV infection as monitored by genotyping can identify women at increased risk of cervical neoplasia more accurately than a single or repeated presence/absence HPV test. The cost effectiveness of such an approach should be investigated by an appropriate, large scale cost–benefit analysis

Changes in HPV prevalence following a national bivalent HPV vaccination programme in Scotland: a 7-year cross-sectional study

Background: On Sept 1, 2008, Scotland launched routine vaccination for human papillomavirus (HPV) types 16 and 18, targeted at 12–13-year-old girls, of whom 92·4% were fully vaccinated in 2008–09. In this study, we report on vaccine effectiveness of the bivalent vaccine in these vaccinated women who attended for routine cervical screening at age 20–21 years. Methods: In this 7-year cross-sectional study (covering birth cohorts 1988–1995), we sampled approximately 1000 samples per year from those attending cervical screening at age 20–21 years and tested each for HPV. By linkage to vaccination records we ascertained prevalence by birth cohort and vaccination status. Estimates of vaccine effectiveness for HPV types 16 and 18, HPV types 31, 33, and 45, other high-risk types, and any HPV were calculated using logistic regression. Findings: In total, 8584 samples were HPV genotyped. Prevalence of HPV types 16 and 18 reduced substantially from 30·0% (95% CI 26·9–33·1) in the 1988 cohort to 4·5% (3·5–5·7) in the 1995 cohort, giving a vaccine effectiveness of 89·1% (85·1–92·3) for those vaccinated at age 12–13 years. All cross-protective types showed significant vaccine effectiveness (HPV type 31, 93·8% [95% CI 83·8–98·5]; HPV type 33, 79·1% [64·2–89·0]; HPV type 45, 82·6% [61·5–93·9]). Unvaccinated individuals born in 1995 had a reduced odds of HPV types 16 and 18 infection compared with those born in 1988 (adjusted odds ratio 0·13 [95% CI 0·06–0·28]) and reduced odds of HPV types 31, 33, and 45 (odds ratio 0·45 [0·23–0·89]). Interpretation: Bivalent vaccination has led to a startling reduction in vaccine and cross-protective HPV types 7 years after vaccination. There is also evidence of herd protection against the vaccine-specific and cross-protective types in unvaccinated individuals born in 1995. These findings should be considered in cost-effectiveness models informing vaccine choice and models to shape the future of cervical screening programmes

Human Papilloma Virus (HPV) Oral Prevalence in Scotland (HOPSCOTCH):a feasibility study in dental settings

The purpose of this study was to test the feasibility of undertaking a full population investigation into the prevalence, incidence, and persistence of oral Human Papilloma Virus (HPV) in Scotland via dental settings. Male and female patients aged 16-69 years were recruited by Research Nurses in 3 primary care and dental outreach teaching centres and 2 General Dental Practices (GDPs), and by Dental Care Teams in 2 further GDPs. Participants completed a questionnaire (via an online tablet computer or paper) with socioeconomic, lifestyle, and sexual history items; and were followed up at 6-months for further questionnaire through appointment or post/online. Saline oral gargle/rinse samples, collected at baseline and follow-up, were subject to molecular HPV genotyping centrally. 1213 dental patients were approached and 402 individuals consented (participation rate 33.1%). 390 completed the baseline questionnaire and 380 provided a baseline oral specimen. Follow-up rate was 61.6% at 6 months. While recruitment was no different in Research Nurse vs Dental Care Team models the Nurse model ensured more rapid recruitment. There were relatively few missing responses in the questionnaire and high levels of disclosure of risk behaviours (99% answered some of the sexual history questions). Data linkage of participant data to routine health records including HPV vaccination data was successful with 99.1% matching. Oral rinse/gargle sample collection and subsequent HPV testing was feasible. Preliminary analyses found over 95% of samples to be valid for molecular HPV detection prevalence of oral HPV infection of 5.5% (95%CI 3.7, 8.3). It is feasible to recruit and follow-up dental patients largely representative / reflective of the wider population, suggesting it would be possible to undertake a study to investigate the prevalence, incidence, and determinants of oral HPV infection in dental settings

Human papillomavirus (HPV) related Oropharynx Cancer in the United Kingdom – An evolution in the understanding of disease aetiology

A rising incidence of oropharyngeal squamous cell carcinoma (OPSCC) incidence has occurred throughout the developed world, where it has been attributed to an increasing impact of human papillomavirus (HPV) on disease etiology. This report presents the findings of a multicenter cross-sectional retrospective study aimed at determining the proportion of HPV-positive and HPV-negative OPSCC within the United Kingdom. Archival tumor tissue blocks from 1,602 patients previously diagnosed with OPSCC (2002-2011) were collated from 11 centers. HPV status was determined with three validated commercial tests to provide valid data for 1,474 cases in total. Corresponding national incidence data from the same decade were obtained from UK Cancer registries. The overall proportion of HPV+ OPSCC between 2002 and 2011 was 51.8% [95% confidence interval (CI), 49.3-54.4], and this remained unchanged throughout the decade [unadjusted RR = 1.00 (95% CI, 0.99-1.02)]. However, over the same period, the incidence of OPSCC in the broader UK population underwent a 2-fold increase [age-standardized rate 2002: 2.1 (95% CI, 1.9-2.2); 2011: 4.1 (95% CI, 4.0-4.3)]. Although the number of OPSCCs diagnosed within the United Kingdom from 2002 to 2011 nearly doubled, the proportion of HPV+ cases remained static at approximately 50%. Our results argue that the rapidly increasing incidence of OPSCC in the United Kingdom cannot be solely attributable to the influence of HPV. The parallel increase in HPV+ and HPV- cases we documented warrants further investigation, so that appropriate future prevention strategies for both types of disease can be implemented.</p