Correlates of cervical mucosal antibodies to human papillomavirus 16: Results from a case control study

Serum and cervicovaginal IgG immune responses against α7 and α9 HPV in non-vaccinated women at risk for cervical cancer: Implication for catch-up prophylactic HPV vaccination

BACKGROUND

Cervical cancer associated with high risk-human papillomavirus (HR-HPV) infection is becoming the one of the most common female cancer in many sub-Saharan African countries. First-generation immigrant African women living in Europe are at-risk for cervical cancer, in a context of social vulnerability, with frequent lack of cervical cancer screening and HPV vaccination.

OBJECTIVE

Our objective was to address immunologically the issue of catch-up prophylactic HPV vaccination in first-generation African immigrant women living in France.

METHODS

IgG immune responses and cross-reactivities to α7 (HPV-18, -45 and -68) and α9 (HPV-16, -31, -33, -35, -52 and -58) HPV types, including 7 HR-HPV targeted by the Gardasil-9® prophylactic vaccine, were evaluated in paired serum and cervicovaginal secretions (CVS) by HPV L1-virus-like particles-based ELISA. Genital HPV were detected by multiplex real time PCR (Seegene, Seoul, South Korea).

RESULTS

Fifty-one immigrant women (mean age, 41.7 years; 72.5% HIV-infected) were prospectively included. More than two-third (68.6%) of them carried genital HPV (group I) while 31.4% were negative (group II). The majority (90.2%) exhibited serum IgG to at least one α7/α9 HR-HPV. Serum HPV-specific IgG were more frequently detected in group I than group II (100% versus 68.7%; P = 0.002). The distribution of serum and genital HPV-specific IgG was similar, but mean number of IgG reactivities to α7/α9 HR-HPV was higher in serum than CVS (5.6 IgG per woman in serum versus 3.2 in CVS; P<0.001). Rates of IgG cross-reactivities against HPV different from detected cervicovaginal HPV were higher in serum and CVS in group I than group II. Finally, the majority of groups I and II women (68.6% and 68.7%, respectively) exhibited serum or cervicovaginal IgG to Gardasil-9® HR-HPV, with higher mean rates in group I than group II (6.1 Gardasil-9® HR-HPV per woman versus 1.4; P<0.01). One-third (31.2%) of group II women did not show any serum and genital HPV-specific IgG.

CONCLUSIONS

Around two-third of first-generation African immigrant women living in France showed frequent ongoing genital HPV infection and high rates of circulating and genital IgG to α7/α9 HPV, generally cross-reacting, avoiding the possibility of catch-up vaccination. Nevertheless, about one-third of women had no evidence of previous HPV infection, or showed only low levels of genital and circulating HR-HPV-specific IgG and could therefore be eligible for catch-up vaccination.

Natural and vaccine-induced B cell-derived systemic and mucosal humoral immunity to human papillomavirus

Introduction: Human papillomavirus (HPV) are the causative agent of mucosal neoplasia. Both cervical, anal and oropharyngeal cancers incidence is constantly increasing, making the HPV infection, a significant worldwide concern. Together, the CD8+ T cytotoxic cell-mediated response and the HPV-specific antibody response control most of the HPV infections before the development of cancers.Areas covered: We searched the MEDLINE and EMBASE databases and identified 228 eligible studies from 1987 to 2019 which examines both naturally acquired and vaccine induced humoral immunity against HPV infection in female and male subjects from worldwide origin. Herein, we synthesize current knowledge on the features of systemic and mucosal humoral immunity against HPV. We discuss the issues of the balance between the viral clearance or the escape to the host immune response, the differences between natural and vaccine-induced HPV-specific antibodies and their neutralizing capability. We also discuss the protection afforded after natural infection or following prophylactic vaccination.Expert opinion: Understanding the antibody response induced by HPV infection has led to the design of first-generation prophylactic vaccines. Now, prophylactic vaccination induces protective and long-lasting antibody response which would also strengthened the natural moderate humoral response in people previously exposed to the virus.

Persisting Antibody Response 9 Years After Bivalent Human Papillomavirus (HPV) Vaccination in a Cohort of Dutch Women: Immune Response and the Relation to Genital HPV Infections

The bivalent human papillomavirus (HPV) vaccine is highly effective and induces robust serological responses. Using a Dutch prospective cohort initiated in 2009, including 744 vaccinated and 294 unvaccinated girls (1993–1994) who provide a vaginal self-swab sample, serum sample, and questionnaire yearly, we report a high, persisting antibody response up to 9 years after vaccination for vaccine types HPV-16 or HPV-18. Antibodies against nonvaccine HPV types 31, 33, 45, 52, and 58 were lower but still significantly higher than in unvaccinated individuals. This was also reflected in the seroprevalence. We compared participant characteristics and antibody levels between vaccinated women with and those without HPV infections 1 year before infection (204 incident and 64 persistent infections), but we observed no consistent difference in type-specific antibody levels. Having a high-risk HPV infection was associated with sexual risk behavior and smoking 1 year before infection. Although high antibody levels are necessary for protection, our study suggests that on the individual level other factors such as HPV exposure or antibody avidity could be important.

Infection and vaccine-induced HPV-specific antibodies in cervicovaginal secretions. A review of the literature

Background

Human papillomavirus (HPV) infects and propagates in the cervical mucosal epithelium. Hence, in addition to assessing systemic immunity, the accurate measurement of cervical immunity is important to evaluate local immune responses to HPV infection and vaccination. This review discusses studies that investigated the presence of infection and vaccine-induced HPV-specific antibodies in cervicovaginal secretions (CVS).

Methods

We searched the two main health sciences databases, PubMed and the ISI Web of Science, from the earliest dates available to March 2019. From the eligible publications, information was extracted regarding: (i) study design, (ii) the reported HPV-specific antibody concentrations in CVS (and the associated serum levels, when provided), (iii) the CVS collection method, and (iv) the immunoassays used.

Results

The systematic search and selection process yielded 44 articles. The evidence of HPV-specific antibodies in CVS after natural infection (26/44) and HPV vaccination (18/44) is discussed. Many studies indicate that HPV-specific antibody detection in CVS is variable but feasible with a variety of collection methods and immunoassays. Most CVS samples were collected by cervicovaginal washing or wicks, and antibody presence was mostly determined by VLP-based ELISAs. The moderate to strong correlation between vaccine-induced antibody levels in serum and in CVS indicates that HPV vaccines generate antibodies that transudate through the cervical mucosal epithelium.

Conclusion

Although HPV-specific antibodies have lower titres in CVS than in serum samples, studies have shown that their detection in CVS is feasible. Nevertheless, the high variability of published observations and the lack of a strictly uniform, well-validated method for the collection, isolation and quantification of antibodies indicates a need for specific methods to improve and standardize the detection of HPV-specific antibodies in CVS.

Serum Immune Profiling for Early Detection of Cervical Disease

Background: The most recent (2012) worldwide estimates from International Agency for Research on Cancer indicate that approximately 528,000 new cases and 270,000 deaths per year are attributed to cervical cancer worldwide. The disease is preventable with HPV vaccination and with early detection and treatment of pre-invasive cervical intraepithelial neoplasia, CIN. Antibodies (Abs) to HPV proteins are under investigation as potential biomarkers for early detection.

Methods: To detect circulating HPV-specific IgG Abs, we developed programmable protein arrays (NAPPA) that display the proteomes of two low-risk HPV types (HPV6 and 11) and ten oncogenic high-risk HPV types (HPV16, 18, 31, 33, 35, 39, 45, 51, 52 and 58). Arrays were probed with sera from women with CIN 0/I (n=78), CIN II/III (n=84), or invasive cervical cancer (ICC, n=83).

Results: Abs to any early (E) HPV protein were detected less frequently in women with CIN 0/I (23.7%) than women with CIN II/III (39.0%) and ICC (46.1%, p<0.04). Of the E Abs, anti-E7 Abs were the most frequently detected (6.6%, 19.5%, and 30.3%, respectively). The least frequently detected Abs were E1 and E2-Abs in CIN 0/I (1.3%) and E1-Abs in CIN II/III (1.2%) and ICC (7.9%). HPV16-specific Abs correlated with HPV16 DNA detected in the cervix in 0% of CIN 0/I, 21.2% of CIN II/III, and 45.5% of ICC. A significant number (29 - 73%) of E4, E7, L1, and L2 Abs had cross-reactivity between HPV types.

Conclusion: HPV protein arrays provide a valuable high-throughput tool for measuring the breadth, specificity, and heterogeneity of the serologic response to HPV in cervical disease.

Development of a simple and quick immunochromatography method for detection of anti-HPV-16/-18 antibodies

Immunochromatography (IC) is widely used to detect target molecules in biological fluids. Since this method can be performed without a special technique or device, IC is a convenient way to assess the existence of antibodies or pathogens such as viruses and bacteria, simply and quickly. In this study, we established an IC method to detect serum antibodies against oncogenic human papillomavirus (HPV)-16 and HPV-18 L1 proteins using recombinant L1 proteins produced by silkworms as antigens. Infection of oncogenic HPVs is a major risk factor of cervical cancer, which is one of the most common cancers in women worldwide. We first measured blood sera of two groups by magnetic beads enzyme-linked immunosorbent assay (MB-ELISA). For the first group, sera were collected prospectively from young women who planned to receive HPV vaccination. The second group consisted of children under 20 years of age, non-vaccinated healthy women, vaccinated healthy women, dysplasia, cervical intraepithelial neoplasia III, and cervical cancer patients. We confirmed that standard vaccination doses significantly increased serum HPV antibody concentrations, and the level was sustained at least more than 30 months after vaccination. In contrast, an increase in antibody concentration was not observed in patients with precancerous cervical changes and cervical cancer. We next measured the samples in both groups using the IC method we originally developed, and found that the measurement values of IC highly correlated with those of MB-ELISA. The simple and quick IC method would be a useful tool for rapid monitoring of L1 specific antibody levels in a non-laboratory environment. With less than one drop of serum, our IC can easily detect serum HPV-16/-18 antibodies within 15 minutes, without the need for electronic devices or techniques.

MBL2 polymorphisms in women with atypical squamous cells of undetermined significance

Infection with high risk Human papillomavirus (HPV) is the main known cause of cervical cancer. HPV induces different grades of lesions: among them, Atypical squamous cells of undetermined significance are abnormal lesions that could evolve in pre-cancer lesions or spontaneously regress. The mannose binding lectin (MBL) is an innate immunity serum protein also found in cervico-vaginal mucosa, whose expression is known to be affected by polymorphisms in exon 1 and promoter of the MBL2 gene. In the present study the possible association between MBL2 functional polymorphisms and susceptibility to develop atypical squamous cells of undetermined significance was investigated in a group of women from North-East of Italy, stratified for HPV infection status. The MBL2 D and O alleles and the deficient producer combined genotypes, responsible for low MBL production, were more represented among atypical squamous cells of undetermined significance positive women than healthy controls and the results were confirmed when only HPV negative samples were considered. These results suggest a possible involvement of MBL2 functional polymorphisms in atypical squamous cells of undetermined significance susceptibility.

The interplay between HPV and host immunity in head and neck squamous cell carcinoma

Persistent infection with human papillomavirus (HPV) type 16 is a major risk factor for the development of head and neck squamous cell carcinoma (HNSCC), in particular oropharyngeal squamous cell carcinoma (OPSCC). The oropharyngeal epithelium differs from the mucosal epithelium at other commonly HPV16-infected sites (i.e., cervix and anogenital region) in that it is juxtaposed with the underlying lymphatic tissue, serving a key immunologic function in the surveillance of inhaled and ingested pathogens. Therefore, the natural history of infection and immune response to HPV at this site may differ from that at other anatomic locations. This review summarizes the literature concerning the adaptive immune response against HPV in the context of HNSCC, with a focus on the T-cell response. Recent studies have shown that a broad repertoire of tumor-infiltrating HPV-specific T-cells are found in nearly all patients with HPV-positive tumors. A systemic response is found in only a proportion of these. Furthermore, the local response is more frequent in OPSCC patients than in cervical cancer patients and HPV-negative OPSCC patients. Despite this, tumor persistence may be facilitated by abnormalities in antigen processing, a skewed T-helper cell response, and an increased local prevalence of T-regulatory cells. Nonetheless, the immunologic profile of HPV-positive vs. HPV-negative HNSCC is associated with a significantly better outcome, and the HPV-specific immune response is suggested to play a role in the significantly better response to therapy of HPV-positive patients. Immunoprofiling may prove a valuable prognostic tool, and immunotherapy trials targeting HPV are underway, providing hope for decreasing treatment-related toxicity.

Mechanisms of virus immune evasion lead to development from chronic inflammation to cancer formation associated with human papillomavirus infection

Human papillomavirus (HPV) has developed strategies to escape eradication by innate and adaptive immunity. Immune response evasion has been considered an important aspect of HPV persistence, which is the main contributing factor leading to HPV-related cancers. HPV-induced cancers expressing viral oncogenes E6 and E7 are potentially recognized by the immune system. The major histocompatibility complex (MHC) class I molecules are patrolled by natural killer cells and CD8+ cytotoxic T lymphocytes, respectively. This system of recognition is a main target for the strategies of immune evasion deployed by viruses. The viral immune evasion proteins constitute useful tools to block defined stages of the MHC class I presentation pathway, and in this way HPV avoids the host immune response. The long latency period from initial infection to persistence signifies that HPV evolves mechanisms to escape the immune response. It has now been established that there are oncogenic mechanisms by which E7 binds to and degrades tumor suppressor Rb, while E6 binds to and inactivates tumor suppressor p53. Therefore, interaction of p53 and pRb proteins can give rise to an increased immortalization and genomic instability. Overexpression of NF-κB in cervical and penile cancers suggests that NF-κB activation is a key modulator in driving chronic inflammation to cancer. HPV oncogene-mediated suppression of NF-κB activity contributes to HPV escape from the immune system. This review focuses on the diverse mechanisms of the virus immune evasion with HPV that leads to chronic inflammation and cancer.

Spinocellular carcinoma from warts in a HPV infection natural history lasting 49 years. Virus strategy or host choice? Implications for researches and therapeutic vaccines

There is a very strong evidence that progression (also to cancer) in variable percentages of cases infected by HPV, HBV, HCV, and HIV depends on host immune response. A large number of observations demonstrate that virus set up a postulated "active strategy" to modify host reactions or to avoid it. But in all those infections it also seems that antigen load (viral RNA or DNA), chronic activation of immune response and time elapsing from the primary infection play a pivotal role in determining clearing or persisting outcomes. My wife's HPV and cancer natural history, lasting 49 years, started at the age of 10 years with facial warts and progressed to CIN 2/3, cervical in situ carcinoma, perineal warts, perianal carcinoma, inguinal lymph nodes, and invasion of bones and muscular structures, until death is paradigmatic: a progressive immune failure was detected in her scaling up all those clinical features, ending in a massive apoptosis of her lymphocytes collected by leukapheresis and cultured with HPV antigens E6/E7, with the aim of obtaining antigen presenting cells and CD8+ specific T lymphocytes. From this experience, a concept of "host choice to reach a tolerance (mainly by a Tregs mediated anergy) or symbiotic-like state" arises, underlining all the affected host's immune-responses to virus persistence (and to consequent tumors). It might be then postulated as the hallmark of a long-term host/parasites co-evolution, and considered a "normal" reaction when the host faces overwhelming numbers of non-self cancer cells (high antigen loads) preceded by persistent virus infections (chronic activation). This happens in patients who do not clear HPV or other viruses soon enough after infection. These observations may lead to a better understanding of many phenomena that are actually difficult to explain or still are open questions. The auto-limiting host's immune-responses are likely to be aimed to avoid risks arising mainly in the protection of "self" (autoimmunity), to prolong its own survival (balance with the virus), to avoid the risk of producing uncontrolled cells (dangerous outcomes). Finally, the postulated negative implications for therapeutic vaccines in cervical cancer, as they really seem to not work till now might be ascribed just to the cited host immune-specific state itself, through an activation induced cell death, elicited by recall antigens (E6/E7 in the case of my wife). Also this latter hypothesis, as well as the previous ones may be of some value to better account for clinical behaviors and researches.

Detection of autoantibodies to survivin in cervical mucus from patients with human papillomavirus-associated cervical cancer and precursor lesions

OBJECTIVES

To investigate the prevalence of mucosal autoantibodies to survivin in patients with human papillomavirus (HPV)-associated cervical cancer and precursor lesions.

METHODS

Cervical mucus from 117 HPV-associated cervical cancer, 102 high-grade squamous intraepithelial lesion (HSIL), 107 low-grade SIL (LSIL), and 80 normal controls were tested by ELISA using either full length recombinant survivin or survivin-derived peptides. Survivin expression in cervical tissue biopsies was studied by Western Blotting.

RESULTS

Cervical mucus from 33 cervical cancer (28.2%), 17 HSIL (16.6%), and 8 LSIL (7.4%) patients reacted with recombinant survivin. The IgA-class antibody response was significantly higher than that observed in the normal controls. The level of mucosal anti-survivin response was associated to the level and intensity of survivin expression in the different lesions. Finally, reactivity against a survivin Nt-derived peptide was found more frequently than reactivity against a Ct-derived peptide.

CONCLUSIONS

IgA-class autoantibodies against survivin are present in a substantial proportion of cervical mucus from patients with HPV-associated cervical cancer, and precursor lesions. Mucosal anti-survivin response is positively associated with the level of survivin expression and the grade of cervical lesion.

Binding of human papillomavirus type 16 to heparan sulfate is inhibited by mucosal antibodies from patients with low-grade squamous intraepithelial lesions but not from cervical cancer patients

Mucosal antibodies against human papillomavirus type 16 (HPV16) capsids have been detected in infected women. To determine whether these antibodies recognize and block the receptor site mediating attachment of HPV16 to heparan sulfate, mucus samples from 126 HPV16-associated low-grade squamous intraepithelial lesion (LSIL) and 85 cervical cancer patients, previously found to react to HPV16 virus-like particles (VLP), and 101 normal controls were tested in an inhibition assay, using HPV16 VLP and heparan sulfate proteoglycan-coated plates. Inhibition levels of 9.3-67.2% were mediated by type-specific antibodies in 94.4% of LSIL patients. Cervical cancer cases showed significantly lower levels of inhibition than LSIL samples (P < 0.0001). The potential of antibodies to inhibit infection was explored in a pseudoinfection system using HPV16 pseudovirions. Inhibition of pseudoinfection by LSIL samples was significantly higher than that observed in the controls (P < 0.001) and cervical cancer cases (P < 0.005). These results indicate that mucosal antibodies inhibiting binding of VLP to heparan sulfate are developed in most LSIL patients, but are hardly present in cervical cancer patients.

HPV Vaccines: today and in the Future

Human papillomavirus (HPV) is responsible for 99.7% of cervical cancer cases and an estimated 5% of all cancers worldwide. The largest burden from HPV-associated cervical cancers is in developing nations where effective cervical cancer screening programs are nonexistent. Even in developed nations, diagnosis and treatment of cervical precancers continue to be large economic burdens. Prophylactic vaccination against HPV is an ideal method for the prevention of cervical cancer and other HPV associated diseases. Safe and effective virus-like-particle-derived prophylactic vaccines are available to most nations. The high cost of the current vaccines makes it out of reach for most developing nations. Because millions of women are already infected with HPV and have serious disease, therapeutic HPV vaccines are being developed to treat these women. This article presents the natural history, oncogenesis, and host immune interactions of HPV and associated diseases. The article also discusses the safety and efficacy of commercially available prophylactic vaccines against HPV, as well as novel prophylactic and therapeutic vaccine delivery strategies in early clinical development.

The relationship between cocaine use and human papillomavirus infections in HIV-seropositive and HIV-seronegative women

Objective. Animal data suggest that cocaine has an immunosuppressive effect, but no human studies have been conducted to assess the relation of cocaine use with human papillomavirus (HPV) infection, the viral cause of cervical cancer. Since both cocaine use and HPV infection are common among HIV-positive women, we sought to determine whether use of cocaine and/or crack influences the natural history of HPV among women with or at high risk of HIV. Methods. Women enrolled in the Women's Interagency HIV Study (2278 HIV-seropositive and 826 high-risk seronegative women) were examined every six months for up to 9.5 years with Pap smear, collection of cervicovaginal lavage (CVL) samples, and detailed questionnaires regarding health and behavior, including use of crack and cocaine (crack/cocaine). CVLs were tested for HPV DNA by PCR, with genotyping for over forty HPV types. Results. In multivariate logistic regression models, censoring women treated for cervical neoplasia, crack/cocaine use within the last six months was associated with prevalent detection of oncogenic HPV DNA (odds ratio [OR] = 1.30 (1.09–1.55)), and with oncogenic HPV-positive squamous intraepithelial lesions (SIL) (OR = 1.70 (1.27–2.27)), following adjustment for age, race, HIV-serostatus, and CD4+ T-cell count, the number of sexual partners in the past six months, and smoking. In multivariate Cox models crack/cocaine use was also associated with a trend that approached significance in regard to incident detection of oncogenic HPV-positive SIL (HR = 1.51, 95% CI 0.99–2.30), and while the rate of oncogenic HPV clearance was not related to cocaine use, the clearance of any SIL was significantly lower in those with versus those without recent crack/cocaine use (HR = 0.57, 95% CI 0.34–0.97). Conclusions. Cocaine use is associated with an increased risk of detection of both prevalent and incident oncogenic HPV infection, as well as an increased risk of HPV-positive SIL over time.

Association between MBL2 gene functional polymorphisms and high-risk human papillomavirus infection in Brazilian women

We studied the association between high-risk human papillomavirus (HPV) infection and MBL2 functional polymorphisms in a group of 180 high-risk HPV-infected women and 180 healthy control subjects. The most frequent high-risk HPV genotypes were 16 (47.2%), 31 (11.7%), 33 (5%), and 18 (2.2%), respectively. Of the 180 HPV-infected women, 99 presented with uterine cervical cancer and 81 did not. No differences in MBL2 genotype or in allelic or haplotype frequencies were found between HPV patients who developed cervical uterine cancer and those who did not. When considering combined genotypes grouped according to MBL production (designated as high, low, and deficient producers), we detected a significant difference between healthy controls and high-risk HPV-positive patients, the latter group showing increased frequencies of deficient-producer genotypes (14.4% vs 9.4% in the healthy control group, corrected p = 0.04). In conclusion, a correlation between MBL2 polymorphisms and high-risk HPV infection was found in this study.

Immune concept of human papillomaviruses and related antigens in local cancer milieu of human cervical neoplasia

It is presently the right time for clarifying human papillomavirus (HPV)-associated cellular immunity and clinical implications before global HPV vaccination programs begin. Infection with oncogenic HPV associates with the progression of cervical neoplasia. Both cellular and humoral immune responses are essential for the clearance of HPV-associated cervical lesions. There is increasing evidence that the immune system plays a pivotal role in determining the outcome of HPV infection. Viruses and associated neoplastic cells are proposed to have evolved mechanisms to avoid immune attack. T-cell-mediated immune responses against oncogenic HPV are believed to play a central role in cervical carcinogenesis. The presence of HPV-specific cytotoxic T lymphocytes (CTL) in a majority of human cervical cancer patients provides an approach for further study of their functional role in modulating this malignancy. Tumor-infiltrating lymphocytes (TIL) develop as manifestations of the recognition and defense against malignant cells by the host immune system. Cancer cells may overcome immune surveillance, either by downregulating the proliferation of HPV-specific CTL, or altering the effector compositions of immune cells against HPV infections. TIL in the tumor microenvironment can be functionally inhibited and lose the ability of clonal proliferation as a result of depressed expression of IL-2Ralpha. The upregulation of inhibitory signaling relates to the modulation of the virus- and/or tumor-specific immune responses. Alteration of host genetic susceptibility may also lead to abnormal immune response as a general genomic instability resulting from virus persistence. Induction of HPV-specific immune responses is anticipated as an intimate point for the treatment of cervical neoplasia.

Chapter 5: Updating the natural history of HPV and anogenital cancer

The major steps in cervical carcinogenesis include infection of the metaplastic epithelium of the cervical transformation zone with one or more of the 12-18 carcinogenic types of human papillomavirus (HPV) infection, viral persistence, clonal progression of the persistently-infected epithelium to cervical precancer, and invasion. Although these fundamental steps are established, several new epidemiologic studies have shed light on the factors that influence each of these transitions. The importance of the transformation zone in cervical cancer has been extended to other HPV-induced cancers such as anal or tonsillar cancers. Natural history studies show that HPV with normal cervical cytology and cervical intraepithelial neoplasia (CIN) grade 1 behave similarly, with the majority of both showing regression. Although these studies have demonstrated the importance of HPV persistence in the development of precancer CIN-3, the timing from infection to evidence of CIN-3 varies from 1 to 10 years. Whether equivalent lesions diagnosed later differ in their natural history remains unknown. Several factors have been implicated in enhancing persistence and/or progression. However, none are consistently associated with both except age: young women are less likely to show persistence and older women with persistence are more likely to be at risk of invasive cancer. Recent studies have also underscored the importance of the host immune response in clearance of established infections. Finally, data on non-cervical HPV infections, such as penile infections are limited to date compared to cervical infections. Several ongoing cohort studies should give us further insight into male infections in the near future.