Mucosal junctions: open doors to HPV and HIV infections?

Principles of epithelial homeostasis control during persistent human papillomavirus infection and its deregulation at the cervical transformation zone

Human papillomaviruses establish a reservoir of infection in the epithelial basal layer. To do this they limit their gene expression to avoid immune detection and modulate epithelial homeostasis pathways to inhibit the timing of basal cell delamination and differentiation to favour persistence. For low-risk Alpha papillomaviruses, which cause benign self-limiting disease in immunocompetent individuals, it appears that cell competition at the lesion edge restricts expansion. These lesions may be considered as self-regulating homeostatic structures, with epithelial cells of the hair follicles and sweat glands, which are proposed targets of the Beta and Mu papillomaviruses, showing similar restrictions to their expansion across the epithelium as a whole. In the absence of immune control, which facilitates deregulated viral gene expression, such lesions can expand, leading to problematic papillomatosis in afflicted individuals. By contrast, he high-risk Alpha HPV types can undergo deregulated viral gene expression in immunocompetent hosts at a number of body sites, including the cervical transformation zone (TZ) where they can drive the formation of neoplasia. Homeostasis at the TZ is poorly understood, but involves two adjacent epithelial cell population, one of which has the potential to stratify and to produce a multilayed squamous epithelium. This process of metaplasia involves a specialised cell type known as the reserve cell, which has for several decades been considered as the cell of origin of cervical cancer. It is becoming clear that during evolution, HPV gene products have acquired functions directly linked to their requirements to modify the normal processes of epithelial homestasis at their various sites of infection. These protein functions are beginning to provide new insight into homeostasis regulation at different body sites, and are likely to be central to our understanding of HPV epithelial tropisms.

Carcinomas of the Uterine Cervix: Comprehensive Review With An Update on Pathogenesis, Nomenclature of Precursor and Invasive Lesions, and Differential Diagnostic Considerations

Most cervical carcinomas and their related lesions are attributed to an infection by human papillomavirus (HPV). The infection usually starts in the basal cells at the squamocolumnar junction. It causes cell proliferation and maturation abnormalities along with nuclear abnormalities resulting in low-grade squamous intraepithelial lesions. An overwhelming majority of these lesions spontaneously disappear, and the infection is cleared. In a small subset of high-risk HPV infection cases, the lesions may persist and progress to high-grade squamous intraepithelial lesions. These are associated with the incorporation of the viral genome into the human genome. Some of the high-grade squamous intraepithelial lesions, over several years, progress to invasive carcinoma. Carcinomas of the cervix are usually squamous cell carcinomas (SCCs), but 20% to 25% of the cases may manifest as adenocarcinomas. Similar to SCC, adenocarcinomas may initially manifest as adenocarcinomas in situ and may progress to invasive carcinomas after a variable period of time. In the recently published World Health Organization classification of female genital tumors, SCCs, and adenocarcinomas of the cervix are divided into HPV-associated and HPV-independent tumors. This review draws on the latest terminology and the several morphologic subtypes recognized for each category.

Association of Righ-Risk Human Papillomavirus and Ureaplasma parvum Co-Infections with Increased Risk of Low-Grade Squamous Intraepithelial Cervical Lesions

Objective:

The present report investigated the rates of coinfections between high-rik human papillomavirus (hrHPV) and the most important human mycoplasmas including Mycoplasma hominis, M. genitalium, Ureaplasma urealyticum and U. parvum in cervical samples of asymptomatic brazilian population.

Methods:

Were included a total of 283 women aged 25–64 years screened by Papanicolaou smears for determining cervical abnormalities, single-target polymerase chain reaction (PCR) and real-time PCR (rt-PCR) for hrHPV and mycoplasmas, respectively.

Results:

A total of 273 (94.5%) women were negative for intraepithelial lesions or malignancy cytology (NILM) and 10 (3.5%) presented abnormal cytology, all low-grade intraepithelial lesions (LSIL). The prevalence of hrHPV was 12.7% and 53.7% for mycoplasmas. U. parvum was the most frequently bacteria detected, followed by Mycoplasma hominis and U. urealyticum. M. genitalium was not detected. Women positive for U. parvum presented a 5-fold increased risk of LSIL (OR = 5.33; 95% CI = 1.09-26.04, P = 0.02) and co-infections between U. parvum and hrHPV increased the risk for LSIL (OR = 3.88; 95% CI = 1.75-8.58, P = 0.0003). However, these associations were not dependent on the concentration of the bacteria.

Conclusion:

Our results reinforced the hypothesis that some mycoplasmas may play a role as cofactors in HPV-mediated cervical carcinogenesis, at least in some populations.

Establishment of Immortalized Laryngeal Epithelial Cells Transfected with Bmi1

Primary laryngeal epithelial cells are essential to exploring the mechanisms of laryngeal and voice disorders; however, they are difficult to study and apply because of their limited life span. The purpose of this study was to develop a stable and reliable in vitro model for the comprehensive study of the pathogenesis of laryngeal and voice diseases. The pLVTHM-Bmi1 plasmid was constructed and used to immortalize primary laryngeal epithelial cells by lentiviral infection. The expressions of Bmi1, human telomerase reverse transcriptase (hTERT), p53, and pRB pathway proteins were detected by western blotting. Functional characteristics of the immortalized cell lines were verified by cell senescence β-galactosidase staining, 5-ethynyl-2′-deoxyuridine cell proliferation test, and flow cytometry. We successfully introduced Bmi into human subglottic (hSG) cells and human ventricle (hV) cells. Both the human immortalized subglottic Bmi1 (hSG-Bmi1) cell line and the human immortalized ventricle Bmi1 (hV-Bmi1) cell line maintained normal epithelial morphology and divided successfully after more than 20 culture passages. As Bmi1 was overexpressed in these cells, the expression of human telomerase reverse transcriptase (hTERT) and phosphorylated Rb increased while p16 and p21 decreased. Following Bmi1-mediated immortalization, cell senescence decreased significantly, and cell proliferation was accelerated. Tumor formation was not observed for hSG, hV, or hSG-Bmi1, and hV-Bmi1 cells in nude mice. hSG-Bmi1 cells dominated by stratified squamous epithelium and hV-Bmi1 cells dominated by columnar cells were established. The new cell lines lay a foundation for the study of the pathogenic mechanisms of laryngeal and voice diseases.

Switches of SOX17 and SOX2 expression in the development of squamous metaplasia and squamous intraepithelial lesions of the uterine cervix

AIMS

The dynamics and topographical distribution of SOX17 and SOX2 expression was studied in the transformation zone (TZ) of the uterine cervix. This TZ is a dynamic area where switches from glandular into squamous epithelium can be recognized, new squamocolumnar junctions are formed, and premalignant lesions originate. SOX17 and SOX2 show mutually exclusive expression patterns in the normal uterine cervix, with SOX2 being exclusively found in squamous epithelium, while SOX17 is detected in endocervical columnar cells and reserve cells.

METHODS AND RESULTS

Normal cervices and squamous intraepithelial lesions (SIL) were studied with immunohistochemistry, methylation of SOX17, human papilloma virus (HPV) genotyping, and in situ hybridization. In the TZ squamous metaplasia originating from these reserve cells can still show SOX17 expression, while also remnants of SOX17-positive immature metaplasia can be recognized in the normal squamous epithelium. SOX17 expression is gradually lost during maturation, resulting in the exclusive expression of SOX2 in the majority of (SIL). This loss of SOX17 expression is independent of methylation of the CpG island in its promotor region. HPV can be detected in SOX17-positive immature metaplastic regions in the immediate vicinity of SOX2-positive SIL, suggesting that switches in SOX17 and 2 expression can occur upon HPV infection.

CONCLUSIONS

This switch in expression, and the strong association between the distribution of reserve cells and squamous areas within the columnar epithelium in the TZ, suggests that reserve cell proliferations, next to basal cells in the squamous epithelium, are potential targets for the formation of squamous lesions upon viral infection.

Dysregulation of Stemness Pathways in HPV Mediated Cervical Malignant Transformation Identifies Potential Oncotherapy Targets

Human papillomavirus (HPV) infection is associated with a range of malignancies that affect anogenital and oropharyngeal sites. α-HPVs dominantly infect basal epithelial cells of mucosal tissues, where they dysregulate cell division and local immunity. The cervix is one of the mucosal sites most susceptible to HPV infections. It consists of anatomically diverse regions, and the majority of cervical intraepithelial neoplasia and cancers arise within the cervical squamo-columnar junction where undifferentiated basal progenitor cells with stem cell properties are found. The cancer stem cell theory particularly associates tumorigenesis, invasion, dissemination, and metastasis with cancer cells exhibiting stem cell properties. In this perspective, we discuss evidence of a cervical cancer stem cell niche and explore the association of stemness related genes with 5-year survival using a publicly available transcriptomic dataset of a cervical cancer cohort. We report that poor prognosis in this cohort correlates with overexpression of a subset of stemness pathway genes, a majority of which regulate the central Focal Adhesion pathway, and are also found to be enriched in the HPV infection pathway. These observations support therapeutic targeting of stemness genes overexpressed by mucosal cells infected with high-risk HPVs.

Alteration of cell junctions during viral infection

Cell junctions serve as a protective barrier for cells and provide an important channel for information transmission between cells and the surrounding environment. Viruses are parasites that invade and commandeer components of host cells in order to survive and replicate, and they have evolved various mechanisms to alter cell junctions to facilitate viral infection. In this review, we examined the current state of knowledge on the action of viruses on host cell junctions. The existing evidence suggests that targeting the molecules involved in the virus-cell junction interaction can prevent the spread of viral diseases.

SOX17 expression and its down-regulation by promoter methylation in cervical adenocarcinoma in situ and adenocarcinoma

AIMS

SOX17 expression has not been studied in glandular lesions of the uterine cervix like adenocarcinoma in situ (AIS) and invasive adenocarcinomas (AdC), whereas SOX17 promoter CpG island methylation has been reported. Therefore, the aim of this study was to relate the topographical distribution of SOX17 expression and SOX17 methylation status to each other, and to SOX2 expression, human papillomavirus (HPV) type, and physical status of the virus.

METHODS AND RESULTS

Immunohistochemistry was used in 45 cases to assess expression of SOX17 and SOX2. SOX17 promoter methylation was determined in 25 cases by means of bisulphite conversion and methylation-specific polymerase chain reaction. SOX17 and SOX2 showed a mutually exclusive expression pattern in normal epithelium, with a sharp delineation in the squamocolumnar junction. SOX17 was found in endocervical columnar and reserve cells, whereas SOX2 was exclusively found in squamous epithelium. In both glandular lesions and cases with coexisting glandular and squamous intraepithelial components, a complex combination of SOX17 and SOX2 expression patterns was seen and mutually exclusive expression was lost. Frequently, gain of expression of SOX2 was found and expression of SOX17 was lost. Methylation of the CpG island in the SOX17 promoter was shown to be strongly associated with loss of expression of SOX17 (P = 0.0016).

CONCLUSIONS

In this study, we show for the first time a direct correlation between the topographical distribution of SOX17 expression and the methylation status of its gene promoter. This explains the heterogeneity of SOX17 expression in the glandular lesions of the cervix. No correlation was found between HPV type and physical status of the virus on the one hand and methylation status on the other.

High prevalence of human papillomavirus infection in HIV-infected women living in French Antilles and French Guiana

An association between HIV infection and cervical cancer, a major public health issue worldwide, has been reported. The aim of this study was to estimate the prevalence of human papillomavirus (HPV) infection and the distribution of HPV genotypes in HIV-infected women living in French Antilles and Guiana and to determine HIV-related characteristics associated with HPV infection. This cross-sectional study included 439 HIV-infected women who were followed between January 2011 and May 2014. Variables related to HIV infections were collected, and cervical samples were analysed to determine HPV genotypes. The median age of the population was 46 years. Estimated prevalence of HPV and high-risk (HR)-HPV infection were 50.1% IC95 [45.4–54.7] and 42% IC95 [37.3–46.6], respectively. HR-HPV 16, 52, 53 or intermediate risk-HPV-68 were found in 25% to 30% of the HPV-infected patients. Gynaecological screening revealed abnormal cervical smear in 24% and 42% of HR-HPV-negative and HPV-positive women, respectively (p = 0.003). Approximately 90% of women were on antiretroviral therapy (ART). Demographic characteristics associated with a higher prevalence of HPV infection included alcohol consumption. Regarding HIV-related characteristics, current therapy on ART, its duration, and undetectable plasma concentrations of RNA-HIV1 were associated with a lower risk of HPV infection. Infection rate with HR-HPV was higher than what is commonly reported in HIV-negative women worldwide and was more likely in women with incomplete HIV suppression. These results highlight the need for supporting adherence to ART, cervical cytology, HPV testing and HPV vaccination.

Pathological mechanisms of laryngeal papillomatosis based on laryngeal epithelial characteristics

Objectives

Human papillomavirus (HPV) infects basal cells of the stratified squamous epithelium through micro epithelial trauma. However, laryngeal papillomatosis commonly appears in any site on the laryngeal mucosa not covered by stratified squamous epithelium. The purpose of this study is to clarify pathological mechanisms of laryngeal papillomatosis based on the characteristics of the laryngeal epithelium.

Study Design

Morphological and immunohistochemical study.

Methods

Larynges from one newborn and two adults were used. Morphological differences in the laryngeal squamo-ciliary junction (lSCJ) were compared to those in the cervical squamo-columnar junction (cSCJ) in a resected cervix uterus. Morphological characteristics of laryngeal epithelial distribution were also compared between the newborn and adult larynges. Immunohistochemical evaluations were performed using p63 (an epithelial stem-cell marker) and integrin-α6 (a cellular HPV receptor).

Results

Morphological differences were noted between the lSCJ and the cSCJ. The lSCJ was present in the adult, but not the newborn supraglottis. Goblet cells in the pseudostratified ciliated columnar epithelium were also found in the adult but not the newborn larynx. In addition, basal cells of the stratified squamous epithelium as well as the pseudostratified ciliated columnar epithelium expressed p63 and integrin-α6 in both newborn and adult larynges.

Conclusions

HPV can infect any immature laryngeal epithelium with or without the lSCJ. Squamous metaplasia of pseudostratified ciliated columnar epithelium with a latent HPV infection can also cause tumorigenesis.

Level of Evidence

N/A.

Human Papillomavirus Infection and Cervical Cancer in HIV+ Women

Human papillomavirus (HPV) is the first identified necessary cause of human cancers and is associated with nearly 100% of all cervical cancers. Compared to the general female populations, HIV+ women have higher prevalence and incidence of cervical HPV infections, higher risks of persistent HPV infections and subsequent cervical intraepithelial lesions, and a higher incidence of cervical cancer. Although the wide use of combined antiretroviral therapy (cART) has improved the immune function and the longevity of HIV+ women, the incidence of cervical cancer in HIV+ women has not declined. For HIV+ women who follow routine cervical cancer screenings, their incidence of cervical cancer is comparable to that in HIV-negative women. Thus, adherence to the recommended cervical cancer screening is still critical for HIV+ women to prevent cervical cancer. Prophylactic HPV vaccines may also benefit HIV+ women, but prospective studies are needed to determine the effectiveness of HPV vaccination on reducing cervical cancer incidence in HIV+ women.

Evidence of synergistic relationships between HIV and Human Papillomavirus (HPV): systematic reviews and meta-analyses of longitudinal studies of HPV acquisition and clearance by HIV status, and of HIV acquisition by HPV status

INTRODUCTION

Observational studies suggest HIV and human papillomavirus (HPV) infections may have multiple interactions. We reviewed the strength of the evidence for the influence of HIV on HPV acquisition and clearance, and the influence of HPV on HIV acquisition.

METHODS

We performed meta-analytic systematic reviews of longitudinal studies of HPV incidence and clearance rate by HIV status (review 1) and of HIV incidence by HPV status (review 2). We pooled relative risk (RR) estimates across studies using random-effect models. I2 statistics and subgroup analyses were used to quantify heterogeneity across estimates and explore the influence of participant and study characteristics including study quality. Publication bias was examined quantitatively with funnel plots and subgroup analysis, as well as qualitatively.

RESULTS AND DISCUSSION

In review 1, 37 publications (25 independent studies) were included in the meta-analysis. HPV incidence (pooled RR = 1.55, 95% CI: 1.29 to 1.88; heterosexual males: pooled RR = 1.95, 95% CI: 1.62, 2.34; females: pooled RR = 1.63, 95% CI: 1.26 to 2.11; men who have sex with men: pooled RR = 1.36, 95% CI: 1.01 to 1.82) and high-risk HPV incidence (pooled RR = 2.20, 95% CI: 1.90 to 2.54) was approximately doubled among people living with HIV (PLHIV) whereas HPV clearance rate (pooled RR = 0.53, 95% CI: 0.42 to 0.67) was approximately halved. In review 2, 14 publications (11 independent studies) were included in the meta-analysis. HIV incidence was almost doubled (pooled RR = 1.91, 95% CI 1.38 to 2.65) in the presence of prevalent HPV infection. There was more evidence of publication bias in review 2, and somewhat greater risk of confounding in studies included in review 1. There was some evidence that adjustment for key confounders strengthened the associations for review 2. Misclassification bias by HIV/HPV exposure status could also have biased estimates toward the null.

CONCLUSIONS

These results provide evidence for synergistic HIV and HPV interactions of clinical and public health relevance. HPV vaccination may directly benefit PLHIV, and help control both HPV and HIV at the population level in high prevalence settings. Our estimates of association are useful for mathematical modelling. Although observational studies can never perfectly control for residual confounding, the evidence presented here lends further support for the presence of biological interactions between HIV and HPV that have a strong plausibility.

Genital mycoplasmas and ureaplasmas in cervicovaginal self-collected samples of reproductive-age women: prevalence and risk factors

The purpose of this study was to characterise the prevalence and risk factors associated with genital mycoplasmas ( Mycoplasma hominis [MH], M. genitalium [MG]) and ureaplasmas ( Ureaplasma urealyticum [UU], U. parvum [UP]) in Portuguese women of reproductive age. The cross-sectional study included 612 cervicovaginal self-collected samples from women aged 15–44 years, tested for MH, MG, UU, UP by polymerase chain reaction. Y chromosome (Yc) DNA was detected as a biomarker of recent unprotected sexual intercourse. The prevalences of UU, UP, MH and MG were 28.4% (95% confidence interval [CI] 25.0–32.1), 22.4% (95% CI 19.3–25.9), 8.5% (95% CI 6.5–11.0) and 0.8% (95% CI 0.4–1.9), respectively. Overall, women aged 20–29 years (odds ratio [OR] 1.78; P = 0.010) and the presence of Yc-DNA (OR 2.33; P = 0.038) were associated with an increased risk of UU. Lifetime number of sexual partners was a predictor of UU, UP and MH (OR 2.46; P < 0.001, OR 2.78; P < 0.001 and OR 1.55; P < 0.001, respectively, for more than one versus one partner). The prevalence of MG was low, while UU, UP and MH were common in Portuguese women of reproductive age. The presence of UU, UP and MH was associated with sexual activity (number of sexual partners), although the consequences of its prevalence are not fully understood and should be further investigated.

Clinical implications of the interaction between HPV and HIV infections

HIV-related immunodeficiency has complex effects on female genital HPV, which include increased risks of infection, multiple types, persistence, reactivation and the risk to develop pre-invasive and invasive disease. Reconstitution of immunity with anti-viral drugs improves cellular immunity, but the risk of HPV-related malignancy remains higher than background incidences and presents at younger ages. Early initiation of antiretroviral therapy (ART) allows improved retention of immune memory through existing antibodies and T-cell clones and improves long-term outcomes. Suggestions of a higher risk to contract HIV if there is existing genital HPV infection are supported and explained by pathophysiological cervical changes, including inflammation. HIV-HPV interactions should influence public health decisions towards prioritising large-scale prepubertal HPV-vaccine roll-out, secondary cervical cancer prevention and early detection programmes for HIV-infected women and early initiation of ART. This chapter will also focus on special considerations for the management of women with co-infection with these two viruses and genital HPV-related diseases.

Deciphering the Multifactorial Susceptibility of Mucosal Junction Cells to HPV Infection and Related Carcinogenesis

Human papillomavirus (HPV)-induced neoplasms have long been considered to originate from viral infection of the basal cell layer of the squamous mucosa. However, this paradigm has been recently undermined by accumulating data supporting the critical role of a discrete population of squamo-columnar (SC) junction cells in the pathogenesis of cervical (pre)cancers. The present review summarizes the current knowledge on junctional cells, discusses their high vulnerability to HPV infection, and stresses the potential clinical/translational value of the novel dualistic model of HPV-related carcinogenesis.

Carcinogenic human papillomavirus infection

Infections with human papillomavirus (HPV) are common and transmitted by direct contact. Although the great majority of infections resolve within 2 years, 13 phylogenetically related, sexually transmitted HPV genotypes, notably HPV16, cause - if not controlled immunologically or by screening - virtually all cervical cancers worldwide, a large fraction of other anogenital cancers and an increasing proportion of oropharyngeal cancers. The carcinogenicity of these HPV types results primarily from the activity of the oncoproteins E6 and E7, which impair growth regulatory pathways. Persistent high-risk HPVs can transition from a productive (virion-producing) to an abortive or transforming infection, after which cancer can result after typically slow accumulation of host genetic mutations. However, which precancerous lesions progress and which do not is unclear; the majority of screening-detected precancers are treated, leading to overtreatment. The discovery of HPV as a carcinogen led to the development of effective preventive vaccines and sensitive HPV DNA and RNA tests. Together, vaccination programmes (the ultimate long-term preventive strategy) and screening using HPV tests could dramatically alter the landscape of HPV-related cancers. HPV testing will probably replace cytology-based cervical screening owing to greater reassurance when the test is negative. However, the effective implementation of HPV vaccination and screening globally remains a challenge.

The Association Between Cervical Human Papillomavirus Infection and Subsequent HIV Acquisition in Tanzanian and Ugandan Women: A Nested Case-Control Study

OBJECTIVE

This study was performed to analyze the associations between cervical human papillomavirus (HPV) infection and human immunodeficiency virus (HIV) acquisition, using cervical samples from previous studies in Tanzania and Uganda.

METHODS

A total of 161 adult women who acquired HIV infection during follow-up and 464 individually matched HIV-seronegative controls were selected from 5 cohorts of women working in bars and recreational facilities. Stored cervical samples were tested for 37 HPV genotypes, using a polymerase chain reaction assay (Roche Linear Array genotyping assay). Multivariate matched analysis using conditional logistic regression was performed to evaluate HPV infection, persistence, and clearance as predictors of HIV acquisition.

RESULTS

HIV seroconverters were significantly more likely than controls to frequently drink alcohol and to be infected with Chlamydia trachomatis, Neisseria gonorrhoeae, or herpes simplex virus type 2. There was no evidence of an association between HIV acquisition and any detectable HPV at the visit prior to HIV seroconversion (adjusted odds ratio, 1.02; 95% confidence interval, .66-1.57) or between HIV acquisition and persistent HPV infection (defined as 2 positive HPV genotype-specific test results at least 6 months apart), cleared HPV infection (defined as a positive HPV test result followed by negative HPV genotype-specific test result), or newly acquired HPV infection, compared with HPV-negative women.

CONCLUSIONS

There was no evidence of association between HPV infection status and subsequent HIV acquisition. These results stand in contrast to other observational studies.

Association Between Serum 25-Hydroxyvitamin D Level and Human Papillomavirus Cervicovaginal Infection in Women in the United States

BACKGROUND

A sufficient level of vitamin D enhances protection against several infectious diseases; however, its association with cervicovaginal human papillomavirus (HPV) infection has not been studied.

METHODS

Data for this cross-sectional study were from National Health and Nutrition Examination Survey 2003-2006. A total of 2353 sexually active women for whom cervicovaginal HPV infection status and serum 25-hydroxyvitamin D (25[OH]D) level were known were studied. Associations between serum 25(OH)D levels (continuous and categorical forms) and cervicovaginal HPV infection (due to high-risk HPV or vaccine-type HPV) were estimated using weighted logistic regression.

RESULTS

After adjustment for age, race/ethnicity, and marital status, the odds of high-risk HPV infection were increased per each 10 ng/mL decrease in serum 25(OH)D level (adjusted odds ratio [aOR], 1.14; 95% confidence interval [CI], 1.02-1.27). Similarly, the odds of vaccine-type HPV infection were increased in women with vitamin D levels that were severely deficient (serum 25[OH]D level, <12 ng/mL; aOR, 2.90; 95% CI, 1.32-6.38), deficient (12-19 ng/mL; aOR, 2.19; 95% CI, 1.08-4.45), and insufficient (20-29 ng/mL; aOR, 2.19; 95% CI, 1.22-3.93), compared with those with vitamin D levels that were sufficient (≥30 ng/mL).

CONCLUSIONS

Cervicovaginal HPV prevalence is associated with less-than-optimal levels of serum vitamin D.

Human papillomavirus in the HIV-infected host: epidemiology and pathogenesis in the antiretroviral era

Human papillomavirus (HPV) infection is associated with essentially all cervical cancers, 80-90 % of anal cancers, and a high proportion of oropharyngeal, vaginal, penile, and vulvar cancers. Malignancy is preceded by the development of precancerous lesions termed high-grade squamous intraepithelial lesions (HSIL). Men and women with human immunodeficiency virus (HIV) infection are at high risk of HPV-related malignancies. The incidence of anal cancer in particular has markedly risen during the antiretroviral era due to the increased longevity of patients with HIV and the absence of anal malignancy screening programs. HIV infection may facilitate initial HPV infection by disrupting epithelial cell tight junctions. Once infection is established, HIV may promote HSIL development via the up-regulation of HPV oncogene expression and impairment of the immune response needed to clear the lesion. HIV-infected women should be screened for cervical HSIL and cancer, and HIV-infected men and women should be considered for anal screening programs.

An update on anal neoplasia

Although anal cancer remains a relatively uncommon tumour its frequency is rising, especially in high-risk groups. It is now well recognized that anal squamous cell carcinoma, the largely predominant tumour type, shares many similarities with cancer of the uterine cervix, with a major role for oncogenic human papilloma viruses in both tumours. Anal squamous precancerous lesions have now to be classified with the same criteria and terminology as their cervical counterparts, by using the Lower Anogenital Squamous Terminology (LAST) proposal. Only p16 protein is a useful marker in this setting at the present time. As most cases of anal cancer are treated by non-surgical procedures, pathology has a limited role in the staging of the disease, except for early lesions treated by local excision, and when the sentinel lymph node procedure is undertaken that is still under evaluation. A variety of other tumour types can occur more rarely, with difficult diagnostic issues, solved in most cases by immunohistochemistry.

HMGB1 secretion during cervical carcinogenesis promotes the acquisition of a tolerogenic functionality by plasmacytoid dendritic cells

Acquisition of an impaired functionality by plasmacytoid dendritic cells (pDCs) contributing to cancer progression has been documented in different types of cancers. In the present study, we postulate that molecules secreted by (pre)neoplastic epithelial cells of the genital tract (cervix/vulva) might attract pDCs but also modify their proper functionality, allowing these cells to initiate a tolerogenic response interfering with antitumor immunity. We demonstrated that pDCs are recruited during the cervical metaplasia-dysplasia-cancer sequence, through the action of their chemoattractant, chemerin. We showed that stimulated-pDCs exposed to cervical/vulvar tumor microenvironment display an altered phenotype. We also demonstrated that cervical/vulvar neoplastic keratinocytes inhibit the proper function of pDCs by decreasing their IFNα secretion in response to CpG oligonucleotides. In parallel, we observed that (pre)neoplastic areas of the cervix are infiltrated by FoxP3(+) Treg cells which colocalize with pDCs. Accordingly, pDCs cocultured with cervical/vulvar neoplastic keratinocytes have the capacity to induce a Treg cell differentiation from naïve CD4(+) T cells, which is in agreement with the development of a tolerogenic response. We identified HMGB1 as a soluble factor produced by neoplastic keratinocytes from the genital tract involved in pDCs functional alteration. Indeed, this molecule inhibited pDC maturation, decreased IFNα secretion following TLR9 stimulation and forced these cells to become tolerogenic. In contrast, inhibition of HMGB1 restored pDC phenotype. Our findings indicate that the use of inhibitory molecules notably directed against HMGB1 in cervical/vulvar (pre)neoplastic lesions might prevent alterations of pDCs functionality and represent an attractive therapeutic strategy to overcome immune tolerance in cancers.

Anal microbiota profiles in HIV-positive and HIV-negative MSM

OBJECTIVE

Because differences in anal microbial populations (microbiota) could affect acquisition of HIV or other conditions, especially among MSM, we profiled the microbiota of the anal canal, assessed its stability, and investigated associations with diversity and composition.

DESIGN

Microbiota profiles in anal swabs collected from 76 MSM (52 in 1989, swab-1; 66 1-5 years later, swab-2) were compared by HIV status (25 HIV-positive), T-cell subsets, and questionnaire data.

METHODS

Bacterial 16S rRNA genes were amplified, sequenced (Illumina MiSeq), and clustered into species-level operational taxonomic units (QIIME and Greengenes). Regression models and Wilcoxon tests were used for associations with alpha diversity (unique operational taxonomic units, Shannon's index). Composition was compared by Adonis (QIIME).

RESULTS

Most anal bacteria were Firmicutes (mean 60.6%, range 21.1-91.1%) or Bacteroidetes (29.4%, 4.1-70.8%). Alpha diversity did not change between the two swabs (N = 42 pairs). In swab-2, HIV-positives had lower alpha diversity (P ≤ 0.04) and altered composition, with fewer Firmicutes and more Fusobacteria taxa (P ≤ 0.03), not completely attributable to very low CD4(+) cell count (median 232 cells/μl), prior AIDS clinical diagnosis (N = 17), or trimethoprim-sulfamethoxazole use (N = 6). Similar but weaker differences were observed in swab-1 (HIV-positive median 580 CD4(+) cells/μl; no trimethoprim-sulfamethoxazole). Associations with T-cell subsets, smoking, and sexual practices were null or inconsistent.

CONCLUSIONS

The anal microbiota of MSM was relatively stable over 1-5 years. However, with uncontrolled, advanced HIV infection, the microbiota had altered composition and reduced diversity partially attributable to antibiotics. Investigations of microbial community associations with other immune perturbations and clinical abnormalities are needed.

High-risk human papillomavirus is transcriptionally active in a subset of sinonasal squamous cell carcinomas

It has been reported that high-risk human papillomavirus (HPV) is a causative agent of a subgroup of oropharyngeal carcinomas. In these tumors, the presence of the transcriptionally active HPV has been proved through the identification of HPV E6 or E7 messenger RNA (mRNA) transcripts. The aim of the study was to assess the HPV-active transcription in a series of sinonasal carcinomas, in correlation with the HPV DNA identification and the p16 immunohistochemistry. Seventy patients with squamous cell carcinomas of the sinonasal tract were included in the survey. The main clinicopathological characteristics were recorded. All tumors were investigated for HPV through the HPV DNA detection by PCR, using the SPF10 primers and by in situ hybridization, using the high-risk GenPoint probe (Dako, Glostrup, Denmark). HPV16 E7 mRNA transcripts detection was performed by RT-PCR in 27 cases. The immunostaining for p16 was performed in all cases. Fourteen carcinomas (20%) were positive for high-risk HPV by PCR: 13 HPV16 and one HPV35. In situ hybridization showed a dotted nuclear positivity in all these cases. HPV16 E7 mRNA was detected in seven tumors harboring HPV16; in the remaining HPV-positive cases, RNA did not reach the quality for analysis. Strong, diffuse positivity for p16 was observed only in the HPV-positive cases. The 14 HPV-positive squamous cell carcinomas were non-keratinizing or scarcely keratinizing tumors. No significant differences were found in terms of gender, age, or staging at diagnosis between HPV-positive and HPV-negative tumors. However, differences in disease-free survival and overall survival between both groups of patients were significant (P=0.004 and P=0.028, respectively). In conclusion, we have shown that HPV is the etiological agent of a subset of sinonasal carcinomas demonstrating the transcriptionally active HPV in these tumors. Immunostaining for p16 can be used as a surrogate marker to identify these tumors.

Association of genital human papillomavirus infection with HIV acquisition: a systematic review and meta-analysis

Objectives

To conduct a systematic review and a meta-analysis of epidemiological studies investigating the association of genital human papillomavirus (HPV) infection and HIV acquisition.

Design

Systematic review and meta-analysis.

Data Sources

Scientific databases and conference abstracts were systematically searched to identify all relevant studies published up to 31 January 2012. Search terms included ‘HIV’, ‘HPV’, ‘human papillomavirus’ and ‘papillomaviridae’ as keywords or text, in the title or abstract.

Methods

To be eligible for inclusion, a study had to be conducted among humans, report data on HIV incidence, and assess genital HPV infection. Summary ORs and 95% CIs were estimated from the extracted data using random-effect meta-analysis. Subgroup analyses were conducted for high-risk (HR) and low-risk (LR) HPV oncogenic risk groups. Between-study heterogeneity and publication bias were assessed.

Results

Of 2601 identified abstracts, six observational studies, comprising 6567 participants were retained for the systematic review and the meta-analysis. HIV acquisition was significantly associated with HPV infection (summary OR=1.96; 95% CI 1.55 to 2.49). HIV incident infection was significantly associated with HR-HPV in five of six studies and with LR-HPV in two out of five. The association was significant for HR-HPV (summary OR=1.92; 95% CI 1.49 to 2.46) and borderline for LR-HPV. No between-study heterogeneity was detected. There was a borderline indication of publication bias.

Conclusions

Further research is needed to elucidate the biological mechanisms involved, and assess the effect of HPV vaccination on HIV acquisition, using vaccines with broad coverage of HPV genotypes. Such research could have important public health implications for HIV prevention.

Towards the eradication of HPV infection through universal specific vaccination

BACKGROUND

The Human Papillomavirus (HPV) is generally recognized to be the direct cause of cervical cancer. The development of effective anti-HPV vaccines, included in the portfolio of recommended vaccinations for any given community, led to the consolidation in many countries of immunization programs to prevent HPV-related cervical cancers. In recent years, increasing evidence in epidemiology and molecular biology have supported the oncogenic role of HPV in the development of other neoplasm including condylomas and penile, anal, vulvar, vaginal, and oro-pharyngeal cancers. Men play a key role in the paradigm of HPV infection: both as patients and as part of the mechanisms of transmission. Data show they are affected almost as often as women. Moreover, no screening procedures for HPV-related disease prevention are applied in men, who fail to undergo routine medical testing by any medical specialist at all. They also do not benefit from government prevention strategies.

DISCUSSION

A panel of experts convened to focus on scientific, medical, and economic studies, and on the achievements from health organizations' intervention programs on the matter. One of the goals was to discuss on the critical issues emerging from the ongoing global implementation of HPV vaccination. A second goal was to identify contributions which could overcome the barriers that impede or delay effective vaccination programs whose purpose is to eradicate the HPV infection both in women and men.

SUMMARY

The reviewed studies on the natural history of HPV infection and related diseases in women and men, the increasing experience of HPV vaccination in women, the analysis of clinical effectiveness vs economic efficacy of HPV vaccination, are even more supportive of the economic sustainability of vaccination programs both in women and men. Those achievements address increasing and needed attention to the issue of social equity in healthcare for both genders.

Latent papillomavirus infections and their regulation

Model systems show that papillomavirus DNA can persist after lesion-regression, and be maintained in a subset of epithelial basal cells. These are very likely long-lived 'stem-cells' or 'stem-like cells', with latency arising via at least two distinct mechanisms. The first involves low-titre virus infection and the retention of viral DNA at levels that are too low to allow life-cycle completion. The second involves lesion-formation, and clearance by the adaptive immune system, followed by persistence with low-level viral gene expression, and possible reactivation upon immune depletion. Mechanical irritation, inflammation and other extracellular influences affect viral copy number in the latently infected cell, and may predispose to lesion-reappearance. Reactivation may account for the recurrence of 'apparently cleared' cervical lesions caused by high-risk types, the appearance of Beta HPV-lesions following immunosuppression, and the development of recurrent respiratory papillomatosis in afflicted children.

HPV Infection in a Cohort of HIV-Positive Men and Women: Prevalence of Oncogenic Genotypes and Predictors of Mucosal Damage at Genital and Oral Sites

The aim of this study was to assess the prevalence of HPV infection and determinants of abnormal cytology in HIV-positive patients. In a cross-sectional study, patients of both sexes, asymptomatic for HPV, underwent anorectal (men)/cervical (women) and oral swabs. Cytology and HPV-PCR detection/genotyping (high- and low-risk genotypes, HR-LR/HPV) were performed. A total of 20% of the 277 enrolled patients showed oral HPV, with no atypical cytology; in men, anal HPV prevalence was 81% with 64% HR genotypes. In women, cervical HPV prevalence was 58% with 37% HR-HPV. The most frequent genotypes were HPV-16 and HPV-18; 37% of men and 20% of women harbored multiple genotypes. Also, 47% of men showed anal squamous intraepithelial lesions (SILs); 6% had high- and 35% low-grade SILs (HSILs/LSILs); 5% had atypical squamous cells of undetermined significance (ASC-US). HR-HPV was independently associated with anal-SIL in men (P = 0.039). Moreover, 37% of women showed cervical SIL: 14 ASC-US, 15 LSILs, 4 HSILs, and 1 in situ cancer. The presence of both LR and HR-HPV in women was independently associated with SIL (P = 0.003 and P = 0.0001). HR-HPV and atypical cytology were frequently identified in our cohort. HPV screening should be mandatory in HIV-infected subjects, and vaccine programs for HPV-negative patients should be implemented.

Human papillomavirus infection and increased risk of HIV acquisition. A systematic review and meta-analysis

OBJECTIVES

Human papillomavirus (HPV), one of the commonest sexually transmitted infections, may be a cofactor in HIV acquisition. We systematically reviewed the evidence for an association of HPV infection with HIV acquisition in women, heterosexual men and men who have sex with men (MSM).

DESIGN

: Systematic review and meta-analysis.

METHODS

Studies meeting inclusion criteria in Pubmed, Embase and conference abstracts up to 29 July 2011 were identified. Random effects meta-analyses were performed to calculate summary hazard ratios (HR). Publication bias and statistical heterogeneity were evaluated and population attributable fractions (PAFs) calculated.

RESULTS

Eight articles were included, with previously unpublished data from five authors. Seven studies found an association between prevalent HPV and HIV acquisition. Risk of HIV acquisition in women doubled with prevalent HPV infection with any genotype [HR = 2.06 (95% CI = 1.44-2.94), I = 0%], although adjustment for confounders was often inadequate. The effect was similar for high-risk [HR = 1.99 (95% CI = 1.54-2.56), I = 8.4%] and low-risk [HR = 2.01 (95% CI = 1.27-3.20), I = 0%] HPV genotypes with weak evidence of publication bias (P = 0.06). Two studies in men were identified: both showed an association between HPV infection and HIV acquisition. Unpublished data from one of two studies in women indicated an association between genotypes targeted by HPV vaccines and HIV acquisition. PAFs for HIV attributable to infection with any HPV genotype ranged between 21 and 37%.

CONCLUSION

If further studies validate the association between HPV infection and HIV acquisition, HPV vaccines may reduce HIV incidence in high HPV prevalence populations, in addition to preventing cervical cancer. HIV surveillance studies during implementation of HPV vaccine programmes are warranted.

The epidemiology and natural history of anal human papillomavirus infection in men who have sex with men

Studies on the epidemiology and natural history of anal human papillomavirus (HPV) infection are essential to understand the significance of this virus in the aetiology of anal cancer in men who have sex with men (MSM). This paper presents a review of studies on anal HPV in MSM. For this review, a Medline search was performed to identify English-language articles published in peer-reviewed journals on the epidemiology, natural history and risk factors for anal HPV infection in MSM. Anal HPV prevalence is high in MSM and infection with multiple HPV types is common. The available prospective data suggest detection of new anal HPV infections may also be common. However, with limited epidemiological data available on infection dynamics and associated behavioural risk factors, it is difficult to draw conclusions on how persistent anal HPV infection is in this population.