Viral etiology of juvenile- and adult-onset squamous papilloma of the larynx

Preclinical Models of Laryngeal Papillomavirus Infection: A Scoping Review

OBJECTIVE

Laryngeal human papillomavirus (HPV) infection causes recurrent respiratory papillomatosis (RRP) and accounts for up to 25% of laryngeal cancers. Lack of satisfactory preclinical models is one reason that treatments for these diseases are limited. We sought to assess the literature describing preclinical models of laryngeal papillomavirus infection.

DATA SOURCES

PubMed, Web of Science, and Scopus were searched from the inception of database through October 2022.

REVIEW METHODS

Studies searched were screened by two investigators. Eligible studies were peer-reviewed, published in English, presented original data, and described attempted models of laryngeal papillomavirus infection. Data examined included type of papillomavirus, infection model, and results including success rate, disease phenotype, and viral retention.

RESULTS

After screening 440 citations and 138 full-text studies, 77 studies published between 1923 and 2022 were included. Models used low-risk HPV or RRP (n = 51 studies), high-risk HPV or laryngeal cancer (n = 16), both low- and high-risk HPV (n = 1), and animal papillomaviruses (n = 9). For RRP, 2D and 3D cell culture models and xenografts retained disease phenotypes and HPV DNA in the short term. Two laryngeal cancer cell lines were consistently HPV-positive in multiple studies. Animal laryngeal infections with animal papillomaviruses resulted in disease and long-term retention of viral DNA.

CONCLUSIONS

Laryngeal papillomavirus infection models have been researched for 100 years and primarily involve low-risk HPV. Most models lose viral DNA after a short duration. Future work is needed to model persistent and recurrent diseases, consistent with RRP and HPV-positive laryngeal cancer.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:3256-3268, 2023.

New Insights into the Impact of Human Papillomavirus on Oral Cancer in Young Patients: Proteomic Approach Reveals a Novel Role for S100A8

Human papillomavirus (HPV) infection has recently been linked to a subset of cancers affecting the oral cavity. However, the molecular mechanisms underlying HPV-driven oral squamous cell carcinoma (OSCC) onset and progression are poorly understood.

METHODS

We performed MS-based proteomics profiling based on HPV status in OSCC in young patients, following biological characterization and cell assays to explore the proteome functional landscape.

RESULTS

Thirty-nine proteins are differentially abundant between HPV (+) and HPV (-) OSCC. Among them, COPS3, DYHC1, and S100A8 are unfavorable for tumor recurrence and survival, in contrast to A2M and Serpine1, low levels of which show an association with better DFS. Remarkably, S100A8 is considered an independent prognostic factor for lower survival rates, and at high levels, it alters tumor-associated immune profiling, showing a lower proportion of M1 macrophages and dendritic cells. HPV (+) OSCC also displayed the pathogen-associated patterns receptor that, when activated, triggered the S100A8 and NFκB inflammatory responses.

CONCLUSION

HPV (+) OSCC has a peculiar microenvironment pattern distinctive from HPV (-), involving the expression of pathogen-associated pattern receptors, S100A8 overexpression, and NFκB activation and responses, which has important consequences in prognosis and may guide therapeutic decisions.

Early Identification and Intervention in Malignant Transformation of Respiratory Papillomatosis

BACKGROUND Human papilloma virus is a ubiquitous and preventable disease with the potential to cause recurrent respiratory papillomatosis. These papillomas affect the mucosal surface of the airways and may lead to airway obstruction. The papillomas require excision when breathing is compromised, and may be fatal if untreated. Rarely, these papillomas progress to cancer. CASE REPORT We report the case of a 21-year-old woman with a history of HPV 11- and 16-positive recurrent laryngeal and respiratory papillomatosis (RRP) since the age of 7 months, requiring multiple local resections in her respiratory tract. Chest CT demonstrated multiple cavitary lesions throughout both lungs with a rapidly growing mass that occupied most of her right lung. Imaging supported a diagnosis of malignant transformation to squamous cell carcinoma of the lung. Bilateral involvement of the lungs indicated stage IVa squamous cell lung cancer, which is not curable. CONCLUSIONS Clinicians should suspect malignant transformation in patients with HPV type 11, especially if they have required multiple excisions. Earlier age at onset and number of excisions may be predictors for severity of the disease course. These patients need continued surveillance imaging to allow early interventions if malignant transformation occurs. We present the case of a 21-year-old being diagnosed with an incurable disease that may have been avoided with adequate preventive care.

PGE2 expression by HPV6/11-induced respiratory papillomas blocks NK cell activation in patients with recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP), a rare chronic disease caused primarily by human papillomavirus types 6 and 11, consists of repeated growth of premalignant papillomas in the airway. RRP is characterized by multiple abnormalities in innate and adaptive immunity. Natural killer (NK) cells play important roles in immune surveillance and are part of the innate immune responses that help prevent tumor growth. We identified that papillomas lack classical class I MHC and retain nonclassical class I MHC expression. Moreover, in this study, we have identified and characterized the mechanism that blocks NK cell targeting of papilloma cells. Here, we show for the first time that the PGE₂ secreted by papilloma cells directly inhibits NK cells activation/degranulation principally through the PGE₂ receptor EP2, and to a lesser extent through EP4 signaling. Thus, papilloma cells have a potent mechanism to block NK cell function that likely supports papilloma cell growth.

A Novel In Vivo Model of Laryngeal Papillomavirus-Associated Disease Using Mus musculus Papillomavirus

Recurrent respiratory papillomatosis (RRP), caused by laryngeal infection with low-risk human papillomaviruses, has devastating effects on vocal communication and quality of life. Factors in RRP onset, other than viral presence in the airway, are poorly understood. RRP research has been stalled by limited preclinical models. The only known papillomavirus able to infect laboratory mice, Mus musculus papillomavirus (MmuPV1), induces disease in a variety of tissues. We hypothesized that MmuPV1 could infect the larynx as a foundation for a preclinical model of RRP. We further hypothesized that epithelial injury would enhance the ability of MmuPV1 to cause laryngeal disease, because injury is a potential factor in RRP and promotes MmuPV1 infection in other tissues. In this report, we infected larynges of NOD scid gamma mice with MmuPV1 with and without vocal fold abrasion and measured infection and disease pathogenesis over 12 weeks. Laryngeal disease incidence and severity increased earlier in mice that underwent injury in addition to infection. However, laryngeal disease emerged in all infected mice by week 12, with or without injury. Secondary laryngeal infections and disease arose in nude mice after MmuPV1 skin infections, confirming that experimentally induced injury is dispensable for laryngeal MmuPV1 infection and disease in immunocompromised mice. Unlike RRP, lesions were relatively flat dysplasias and they could progress to cancer. Similar to RRP, MmuPV1 transcript was detected in all laryngeal disease and in clinically normal larynges. MmuPV1 capsid protein was largely absent from the larynx, but productive infection arose in a case of squamous metaplasia at the level of the cricoid cartilage. Similar to RRP, disease spread beyond the larynx to the trachea and bronchi. This first report of laryngeal MmuPV1 infection provides a foundation for a preclinical model of RRP.

Infantile recurrent respiratory papillomatosis: review of adjuvant therapies

BACKGROUND

Recurrent respiratory papillomatosis is a potentially life-threatening condition characterised by the growth of exophytic lesions within the larynx and trachea. The principal aim of management is maintenance of an adequate airway by surgical debulking. Several adjuvant therapies have been used to varying effect to reduce the burden of this disease and increase the interval between debulking procedures. The most severe cases present in children aged under three years, who are therefore most likely to need adjuvant therapies. The current evidence base on adjuvant treatments relating to children who present aged under three years has been reviewed.

METHODS

A literature review of articles in Cochrane, PubMed and Embase databases was carried out. Given the rarity of the condition in this age group, all the literature relates to case reports and case series.

RESULTS AND CONCLUSION

The following adjuvant therapies have been used in children who presented under three years of age: quadrivalent human papilloma virus vaccine, intralesional cidofovir, pegylated interferon, alpha-interferon, cimetidine and cetuximab.

HPV-Associated Benign Squamous Cell Papillomas in the Upper Aero-Digestive Tract and Their Malignant Potential

Squamous cell papilloma (SCP) in the upper aero-digestive tract is a rare disease entity with bimodal age presentation both at childhood and in adults. It originates from stratified squamous and/or respiratory epithelium. Traditionally, SCPs have been linked to chemical or mechanical irritation but, since the 1980s, they have also been associated with human papillomavirus (HPV) infection. Approximately 30% of the head and neck SCPs are associated with HPV infection, with this association being highest for laryngeal papillomas (76–94%), followed by oral (27–48%), sinonasal (25–40%), and oropharyngeal papillomas (6–7%). There is, however, a wide variation in HPV prevalence, the highest being in esophageal SCPs (11–57%). HPV6 and HPV11 are the two main HPV genotypes present, but these are also high-risk HPVs as they are infrequently detected. Some 20% of the oral and oropharyngeal papillomas also contain cutaneous HPV genotypes. Despite their benign morphology, some SCPs tend to recur and even undergo malignant transformation. The highest malignant potential is associated with sinonasal inverted papillomas (7–11%). This review discusses the evidence regarding HPV etiology of benign SCPs in the upper aero-digestive tract and their HPV-related malignant transformation. In addition, studies on HPV exposure at an early age are discussed, as are the animal models shedding light on HPV transmission, viral latency, and its reactivation.

Virus-Associated Biomarkers in Oropharyngeal and Nasopharyngeal Cancers and Recurrent Respiratory Papillomatosis

Nasopharyngeal cancer (NPC) is known to be associated with Epstein–Barr virus (EBV). Pre-treatment and post-treatment detection of plasma cell-free EBV DNA has been shown to be useful as a diagnostic as well as a prognostic factor in NPC. On the other hand, the incidence of human papillomavirus (HPV)-associated oropharyngeal cancer (OPC) is increasing. In contrast to cervical cancer, which is classically known to be an HPV-associated malignancy, HPV testing is not clinically applied for OPC, except for p16 immunostaining as a surrogate marker of HPV infection. One of the major characteristics of HPV-associated OPC is its association with a good prognosis compared with non-HPV-associated OPC. However, some patients still have a poor prognosis. Another characteristic of HPV-associated OPC is the distinct risk factor of high sexual activity. Establishing a biomarker for the prediction of the prognosis before and/or after initial treatment, as well as for diagnosis in populations at high risk, is of marked interest. With this background, HPV DNA detection in plasma and oral rinses has become an area of focus. In this review, the current significance of HPV DNA detection in plasma and oral rinse samples, as well as serum HPV antibody levels, is evaluated.

Immune Therapy Targeting E6/E7 Oncogenes of Human Paillomavirus Type 6 (HPV-6) Reduces or Eliminates the Need for Surgical Intervention in the Treatment of HPV-6 Associated Recurrent Respiratory Papillomatosis

: Background: Recurrent respiratory papillomatosis (RRP) is a rare disorder characterized by the generation of papillomas of the aerodigestive tract, usually associated with human papilloma virus (HPV) subtypes 6, 11. INO-3106 is a DNA plasmid-based immunotherapy targeting E6 and E7 proteins of HPV6, in order to create a robust immune T cell response.

METHODS

Testing of INO-3016 in animal models confirmed immunogenicity of the DNA-based therapy. A single-site open-label Phase 1 study was initiated for patients with HPV6-positive RRP. Patients were dosed with INO-3106 with or without INO-9012, a DNA plasmid immunotherapy that encodes IL-12, delivered intramuscularly (IM) in combination with electroporation (EP) with the CELLECTRA^® device. Patients received an escalating dose of INO-3106, 3 mg once and then 6 mg for three additional doses, each dose three weeks apart, with the third and fourth doses co-administered with INO-9012. The primary objective of the study was to evaluate the safety and tolerability of INO-3106 with and without INO-9012. The secondary objective was to determine cellular immune responses to INO-3106 with and without INO-9012. Exploratory objectives included preliminary clinical efficacy to the therapy.

RESULTS

Three patients were enrolled in this study, of which two had RRP. Study therapy was well-tolerated, with no related serious adverse events and all related adverse events (AEs) were low-grade. Injection site pain was the most common related AE reported. Immunogenicity was evidenced by multiple immune assays showing engagement and expansion of an HPV6-specific cellular response, including cytotoxic T cells. Preliminary efficacy was demonstrated in patients with RRP in the form of reduction in need for surgical intervention for papilloma growth. Prior to intervention, both patients required surgical intervention approximately every 180 days. One patient demonstrated a greater than three-fold increase in surgery avoidance (584 days) and the other patient remains completely surgery-free as of the last contact at 915 days, a greater than 5-fold increase in surgery interval.

CONCLUSION

INO-3106 with and without INO-9012 was well tolerated, immunogenic and demonstrated preliminary efficacy in patients with HPV6-associated RRP aerodigestive lesions. Further clinical study is indicated.

Update on Recurrent Respiratory Papillomatosis

Recurrent respiratory papillomatosis (RRP) remains a challenging disease afflicting children and adults, resulting in an estimated $120 million per year in United States healthcare-related costs, with annual costs per patient approaching $60,000. Although the prevalence of RRP has declined, RRP remains the most common benign laryngeal neoplasm in children. RRP is unique in its high rate of multisite recurrence, its high burden on patient quality of life, and its high associated healthcare costs. This article summarizes current understanding of the natural history and quality of life burden of RRP, and basic science advancements in prevention and treatment.

Management of laryngeal papillomatosis using coblation: another option of surgical intervention

PURPOSE

Recurrent respiratory papillomatosis is a disease caused by the human papilloma virus (HPV). HPV is frequently localised in the larynx. The disease tends to recur and frequent intervention is usually required. Management modules include surgical intervention using microdebriders or laser ablation as well as adjuvant treatments which aim mainly at maintaining an adequate airway and secondly to manage dysphonia caused by the growth on the vocal folds. In this pilot study, another surgical modality is trialled using plasma-mediated radio-frequency ablation (coblation).

METHODS

Retrospective study examining management of 15 adult patients diagnosed with recurrent laryngeal papillomatosis and surgically treated using coblation. One patient required multiple procedures. Pre-operative assessment in voice clinic evaluating voice quality and its impact on patients' life-quality using voice parameters and self-assessment questionnaires. Follow-up post-operatively using the same parameters from 4 to 6 weeks after surgery until up to 2 years later to check recurrence rate. No other adjuvant treatment was used and all patients received post-operative voice therapy.

RESULTS

78.6% of patients did not show evidence of recurrence during the study period. Improvement in voice handicap following first intervention is reported and recurrence rate in the rest of the sample reported.

CONCLUSIONS

The results of this small sample seem to support the previous small studies' findings that coblation is a good excisional technique to use for removal of laryngeal papillomatosis. Recurrence rates seem to be slightly lower than rates reported in the literature for the other surgical modalities.

LEVEL OF EVIDENCE

IV.

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.

HPV vaccination as preventive approach for recurrent respiratory papillomatosis - a 22-year retrospective clinical analysis

BACKGROUND

Recurrent respiratory papillomatosis (RRP) is a rare, benign disease of the aerodigestive tract, especially the larynx, caused by infection with the human papillomavirus (HPV) types 6 or 11. Current management focuses on surgical debulking with microdebrider of papillomatous lesions with or without concurrent adjuvant therapy, e.g. Cidofovir®. This retrospective study evaluates the results of patients treated at a department of the university clinic between 1990 and 2012 and compares the results of the conventional treatment with a new treatment approach using adjuvant vaccination with Gardasil®.

METHODS

A retrospective Kaplan Maier analysis of n = 24 patients diagnosed and treated with RPR was performed. The records were reviewed for gender, age at the time of first manifestation of disease and time to recurrence.

RESULTS

Only n = 2 (15.4%) of the n = 13 vaccinated patients developed a recurrence of the disease after a mean time of 54.9 months (SD: 9.5 months). All patients who were not vaccinated (n = 11; 100%) developed a relapse after a mean time of 12.3 months (SD: 9.72 months).

CONCLUSION

We propose that adjuvant HPV vaccination with Gardasil® might have a preventive effect in RRP by occluding new papilloma formation.

Development of HPV Vaccines for HPV-associated Head and Neck Squamous Cell Carcinoma

High-risk genotypes of the human papillomavirus (HPV), particularly HPV type 16, are found in a distinct subset of head and neck squamous cell carcinomas (HNSCC). Thus, these HPV-associated HNSCC may be prevented or treated by vaccines designed to induce appropriate HPV virus-specific immune responses. Infection by HPV may be prevented by neutralizing antibodies specific for the viral capsid proteins. In clinical trials, vaccines comprised of HPV virus-like particles (VLPs) have shown great promise as prophylactic HPV vaccines. However, given that capsid proteins are not expressed at detectable levels by infected basal keratinocytes, vaccines with therapeutic potential must target other non-structural viral antigens. Two HPV oncogenic proteins, E6 and E7, are important in the induction and maintenance of cellular transformation and are co-expressed in the majority of HPV-containing carcinomas. Therefore, therapeutic vaccines targeting these proteins may have potential to control HPV-associated malignancies. Various candidate therapeutic HPV vaccines are currently being tested whereby E6 and/or E7 is administered in live vectors, in peptides or protein, in nucleic acid form, as components of chimeric VLPs, or in cell-based vaccines. Encouraging results from experimental vaccination systems in animal models have led to several prophylactic and therapeutic vaccine clinical trials. Should they fulfill their promise, these vaccines may prevent HPV infection or control its potentially life-threatening consequences in humans.

Poly(I:C) induces controlled release of IL-36γ from keratinocytes in the absence of cell death

The epithelium is part of an integrated immune system where cytokines, toll-like receptors and their ligands, and extracellular vesicles play a crucial role in initiating an innate immune response. IL-36γ is a pro-inflammatory member of the IL-1 family that is mainly expressed by epithelial cells, but regulation of its expression and release are only beginning to be understood. Previous studies reported that IL-36γ is abundant in recurrent respiratory papillomatosis, a rare but devastating disease caused by human papillomaviruses (HPV) types 6 and 11, in which papillomas recurrently grow in and block the airway. Despite the overexpression of IL-36γ, papilloma tissues show no evidence of inflammation, possibly due to suppression of its release by HPVs. We have used primary human foreskin keratinocytes as a model to study IL-36γ regulation in normal epithelial cells. Low doses of poly(I:C) mediate expression and release of IL-36γ without inducing the cell death reported by those using high doses. PKR, an enzyme required for inflammasome activation, does not contribute to controlled release of IL36γ. The keratinocytes secrete IL-36γ in two forms, soluble and in extracellular vesicles. We conclude that there are two separately regulated pathways for the controlled secretion of IL-36γ from keratinocytes, which could contribute to the modulation of both local and systemic immune responses to viruses and other pathogens.

Juvenile recurrent respiratory papillomatosis: 10-year audit and Australian prevalence estimates

OBJECTIVES/HYPOTHESIS

To estimate the prevalence of juvenile onset recurrent respiratory papillomatosis (RRP) in Australia, describe its epidemiological profile, and assess the positive predictive value of International Classification of Disease, 10th revision (ICD-10) code D14.1 (benign neoplasm of larynx) in children for hospitalization due to RRP.

STUDY DESIGN

Retrospective case series.

METHODS

Retrospective case review undertaken at the three tertiary pediatric hospitals in New South Wales (Australia's largest state), by reviewing medical records of patients aged 0 to 16 years admitted during 2000-2009 containing the ICD-10 Australian modification code D14.1 or other possible disease (D14.2-4, D14.3, D14.4) and RRP-related procedure codes. For RRP diagnoses, we recorded treatment dates, length of stay, extent of disease, and surgical and adjuvant treatments. The positive predictive value (PPV) of code D14.1 and median number of hospitalizations per year were applied to national hospital separations data from 2000/2001 to 2012/2013 to estimate disease prevalence.

RESULTS

We identified 30 cases of RRP using code D14.1, which had a PPV of 98.1%, with no further cases identified using other codes. Fifty-seven percent of cases were female, median age of onset was 36 months, and median treatment duration was 36 months (mean = 40 months, range = 1-118). There was one patient death. Between 2000 and 2013, the estimated national prevalence rate was 0.81 per 100,000 aged < 15 years, peaking at age 5 to 9 years (1.1 per 100,000).

CONCLUSIONS

RRP prevalence can be monitored after human papillomavirus vaccination programs using routine hospital data.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:2827-2832, 2016.

Office-based Management of Recurrent Respiratory Papilloma

This review will highlight the indications and benefits of office-based therapy for recurrent respiratory papillomatosis (RRP) and discuss the utilization of photo-dynamic lasers and adjuvant medical therapy in office-based settings. Office-based management of RRP allows for more timely interventions, is preferred by the majority of patients, and negates the risk of general anesthesia. Current literature argues for the utilization of KTP laser over CO₂ laser for office-based treatment of RRP. Medical therapies for RRP are limited, but agents such as bevacizumab are promising and have been shown to reduce disease burden. Medical therapies that can induce disease remission are still needed. Office-based procedures save time and healthcare expenses compared to like procedures in the operating room. However, the increased frequency for office-based procedures predicts similar overall healthcare costs for office-based and OR laser excision of RRP. Office-based management of RRP is a feasible and well-tolerated strategy in appropriately selected patients with adequate local anesthesia.

Epiglottic masses identified on CT imaging: A case report and review of the broad differential diagnosis

Epiglottic masses may be cystic, granulomatous, infectious, benign or malignant neoplastic, or manifestations of a systemic disease. When large in size, the airway may become obstructed, and when accompanied by suspicious features such as cartilaginous invasion, extension to the pre-epiglottic or para-glottic spaces, or lymphadenopathy, the radiologist must consider malignancy as a primary differential diagnosis. However, when only benign features are identified, the differential diagnosis is broad. We present a 65-year-old female with an incidental 1 cm exophytic, pedunculated, papillomatous lesion on the laryngeal surface of the epiglottis discovered upon endoscopic evaluation for dyspepsia and heartburn. Because of her risk factors for malignancy, CT scan was requested and revealed only benign features. Subsequent excisional biopsy revealed a benign squamous papilloma; however, multiple additional differential considerations were entertained preoperatively.

Estimating the incidence and prevalence of juvenile-onset recurrent respiratory papillomatosis in publicly and privately insured claims databases in the United States

BACKGROUND

Juvenile-onset recurrent respiratory papillomatosis (JORRP) is a chronic disease caused by human papillomavirus types 6 and 11. It is associated with significant morbidity that places intense physical, psychological, and financial strain on patients and their families. Few studies have assessed the incidence and prevalence of JORRP in the United States.

METHODS

This retrospective, longitudinal cohort study was performed using data from a pair of large insurance claims databases in the United States. The Optum Clinformatics and Truven MarketScan Medicaid databases represent a sample of privately and publicly insured children, respectively. Cohorts of children aged 0 to 17 years were created within each database to estimate the incidence and prevalence of JORRP in 2006. Claims-based algorithms were designed to capture as many potential cases as possible. To improve the accuracy of the incidence and prevalence estimates, chart validation was performed to estimate the positive predictive value (PPV) of the claims-based algorithms.

RESULTS

The overall PPV-adjusted incidence of JORRP in 2006 was 0.51 per 100,000 in Optum and 1.03 per 100,000 in the MarketScan Medicaid population. Peak incidence was observed among 0- to 4-year-olds in both databases. The PPV-adjusted prevalence of JORRP in 2006 was 1.45 and 2.93 per 100,000 in the Optum and MarketScan Medicaid cohorts, respectively.

CONCLUSIONS

Although relatively uncommon, JORRP represents a disease with significant morbidity. The incidence and prevalence of JORRP in publicly insured children were consistently higher than those covered by private insurance plans, suggesting an increased burden of illness among those with lower socioeconomic status.

Risk factors for aggressive recurrent respiratory papillomatosis in adults and juveniles

In this cohort study we examined whether gender, age at onset, observation time or human papillomavirus (HPV) genotype are risk factors for an aggressive clinical course in Recurrent Respiratory Papillomatosis (RRP). Clinical data from patient records comprised gender, age at onset, date of first endolaryngeal procedure with biopsy, date of last follow-up, total number of endolaryngeal procedures, and complications during the observation period. Disease was defined as juvenile (JoRRP) or adult onset (AoRRP) according to whether the disease was acquired before or after the age of 18. Aggressive disease was defined as distal spread, tracheostomy, four surgical operations annually or >10 surgeries in total. DNA was extracted from formalin-fixed paraffin-embedded tissue. HPV genotyping was performed by quantitative PCR assay identifying 15 HPV genotypes. The study included 224 patients. The majority were males (141/174 in AoRRPs and 31/50 in JoRRPs; p = 0.005). The median follow-up from initial diagnosis was 12.0 years (IQR 3.7-32.9) for JoRRPs and 4.0 years (IQR 0.8-11.7) for AoRRPs. The disease was more aggressive in juveniles than adults (p<0.001), a difference that disappeared after 10 years' observation. JoRRPs with aggressive disease were younger at onset (mean difference 4.6 years, 95%CI [2.4, 6.8], p = 0.009). HPV6 or -11 was present in all HPV-positive papillomas. HPV11 was more prevalent in aggressive disease, and HPV6 in non-aggressive disease (p<0.001). Multiple logistic regression revealed that only age at onset (OR = 0.69, 95% CI [0.53, 0.88], p = 0.003) was associated with aggressive disease in juveniles, while HPV11 (OR = 3.74, 95% CI [1.40, 9.97], p = 0.008) and observation time >10 years (OR = 13.41, 95% CI [5.46, 32.99[, p<001) were risk factors in adults. In conclusion, the only significant risk factor for developing aggressive disease in JoRRPs was age at onset, but both HPV11 and observation time >10 years were risk factors for an aggressive disease course in AoRRPs.

The paediatric story of human papillomavirus (Review)

Human papillomavirus (HPV) is composed of a particularly heterogeneous family of DNA viruses, which has gained much attention in recent years due to the discoveries of Professor Harald zur Hausen, who first identified a connection between HPV and cervical cancer. Professor Harald zur Hausen, the 'Father of HPV Virology', was the recipient of the 2008 Nobel Prize. HPV can be transmitted through physical contact via autoinoculation or fomites, sexual contact, as well as vertically from the HPV-positive mother to her newborn, causing subclinical or clinical infections. In infancy and childhood, HPV-associated clinical infections include skin warts, genital warts and juvenile recurrent respiratory papillomatosis, while cervical squamous intraepithelial lesions have also been reported among adolescent girls. To date, several research teams, worldwide, have extensively investigated HPV from the paediatric point of view. This primitive effort has been performed before the recent great expansion of paediatric HPV research due to the vaccination programmes against HPV, which were introduced into clinical practice in 2006. In this review article, we present a brief overview of paediatric HPV research after the first report in 1978 involving children in the research of HPV until the time point of this great expansion. In the future, it is expected that further unresolved issues will be addressed and clarified, as the paediatric story of HPV remains a challenging research target.

Risk factors for the development and severity of juvenile-onset recurrent respiratory papillomatosis: a systematic review

OBJECTIVES

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is a rare yet aggressive disease caused by human papillomavirus (HPV). Although many newborns are likely exposed to HPV, few develop JoRRP and the clinical course of the disease varies from one child to another. This systematic review seeks to provide an up-to-date understanding of the risk factors for acquisition and severity.

METHODS

We conducted a comprehensive literature search in EMBASE, MEDLINE and EBMR databases using various combinations of keywords related to JoRRP etiology, risk factors and severity. We also searched Google Scholar and the reference lists of eligible studies. Our search was limited to original studies published in French or English between 1995 and July 2012 and to patients under 20 years of age.

RESULTS

Of 1362 citations, we retrieved 102 articles and found 14 additional studies. We retained 32 studies meeting inclusion criteria. All were observational and together included 2296 JoRRP cases. Risk factors could be classified mainly as maternal and birth history, viral genotype, and host factors. A history of genital warts during pregnancy and delivery was strongly linked to the development of JoRRP. Depending on ethnicity, specific human leukocyte antigen class II alleles and immune response factors were important determinants of JoRRP acquisition and severity. HPV-11 genotype and younger age at onset of JoRRP were important predictors of severity.

CONCLUSIONS

Genetic and immunological profiles underlying the acquisition and clinical course are not readily modifiable. Thus, preventing condylomas in women of childbearing age could reduce the burden of this life-threatening disease.

Human papillomavirus genome variants

Amongst the human papillomaviruses (HPVs), the genus Alphapapillomavirus contains HPV types that are uniquely pathogenic. They can be classified into species and types based on genetic distances between viral genomes. Current circulating infectious HPVs constitute a set of viral genomes that have evolved with the rapid expansion of the human population. Viral variants were initially identified through restriction enzyme polymorphisms and more recently through sequence determination of viral fragments. Using partial sequence information, the history of variants, and the association of HPV variants with disease will be discussed with the main focus on the recent utilization of full genome sequence information for variant analyses. The use of multiple sequence alignments of complete viral genomes and phylogenetic analyses have begun to define variant lineages and sublineages using empirically defined differences of 1.0-10.0% and 0.5-1.0%, respectively. These studies provide the basis to define the genetics of HPV pathogenesis.

An update on oral human papillomavirus infection

Human papillomavirus (HPV) constitutes the majority of newly acquired sexually transmitted infections (STIs) in United States as per the centers for disease control factsheet 2013. Genital HPV is the most common STI with incidence of about 5.5 million world-wide, nearly 75% of sexually active men and women have been exposed to HPV at some point in their lives. Oral Sexual behavior is an important contributor to infection of HPV in the oral mucosa especially in cases known to practice high risk behavior and initiating the same at an early age. HPV infection of the oral mucosa currents is believed to affect 1-50% of the general population, depending on the method used for diagnosis. The immune system clears most HPV naturally within 2 years (about 90%), but the ones that persist can cause serious diseases. HPV is an essential carcinogen being implicated increasingly in association with cancers occurring at numerous sites in the body. Though there does not occur any specific treatment for the HPV infection, the diseases it causes are treatable such as genital warts, cervical and other cancers.

An update on oral human papillomavirus infection

Human papillomavirus (HPV) constitutes the majority of newly acquired sexually transmitted infections (STIs) in United States as per the centers for disease control factsheet 2013. Genital HPV is the most common STI with incidence of about 5.5 million world-wide, nearly 75% of sexually active men and women have been exposed to HPV at some point in their lives. Oral Sexual behavior is an important contributor to infection of HPV in the oral mucosa especially in cases known to practice high risk behavior and initiating the same at an early age. HPV infection of the oral mucosa currents is believed to affect 1-50% of the general population, depending on the method used for diagnosis. The immune system clears most HPV naturally within 2 years (about 90%), but the ones that persist can cause serious diseases. HPV is an essential carcinogen being implicated increasingly in association with cancers occurring at numerous sites in the body. Though there does not occur any specific treatment for the HPV infection, the diseases it causes are treatable such as genital warts, cervical and other cancers.

The biology of papillomavirus latency

The presence of viral DNA in the absence of disease has suggested that papillomaviruses, like many other viruses, can exist as latent infections in the skin or other epithelial sites. In animal models, where detailed investigation has been carried out, papillomavirus DNA can be found at sites of previous infection following immune regression, with the site of latent infection being the epithelial basal layer. Such studies suggest that immune surveillance can restrict viral gene expression in the basal and parabasal layers without efficiently suppressing viral genome replication, most probably through the action of memory T-cells in the skin or dermis. Although gradual papillomavirus genome loss appears to occur over time at latent sites, immunosuppression can arrest this, and can lead to an elevation in viral genome copy number in experimental systems. In addition to immune-mediated latency, it appears that a similar situation can be achieved following infection at low virus titres and/or infection at epithelial sites where the virus life cycle is not properly supported. Such silent of asymptomatic infections do not necessarily involve the host immune system and may be controlled by different mechanisms. It appears that virus reactivation can be triggered by mechanical irritation, wounding or by UV irradiation which changes the local environment. Although the duration of papillomavirus latency in humans is not yet known, it is likely that some of the basic principles will resemble those elucidated in these model systems, and that persistence in the absence of disease may be the default outcome for at least some period of time following regression.

Recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is a rare, benign disease with no known cure. RRP is caused by infection of the upper aerodigestive tract with the human papillomavirus (HPV). Passage through the birth canal is thought to be the initial transmission event, but infection may occur in utero. HPV vaccines have helped to provide protection from cervical cancer; however, their role in the prevention of RRP is undetermined. Clinical presentation of initial symptoms of RRP may be subtle. RRP course varies, and current management focuses on surgical debulking of papillomatous lesions with or without concurrent adjuvant therapy.

Delineating an epigenetic continuum in head and neck cancer

A tissue field of somatic genetic alterations precedes the histopathological phenotypic changes of carcinoma. Genomic changes could be of potential use in the diagnosis and prognosis of pre-invasive squamous head and neck carcinoma (HNSCC) lesions and as markers for cancer risk assessment. Studies of sequential molecular alterations and genetic progression of pre-invasive HNSCC have not been clearly defined. Studies have shown recurring alterations at chromosome 9p21 (location of the CDKN2A) and TP53 mutations in the early stages of HNSCC. However, gene silencing via hypermethylation is still a relatively new idea in the development of HNSCC and little is known about the contribution of epigenetics to the development of neoplasia, its transformation, progression, and recurrence in HNSCC. This review examines the role of promoter hypermethylation of tumor suppressor genes in the progression continuum from benign papillomas to malignancy in HNSCC.

Promoter methylation in head and neck tumorigenesis

In addition to genetic alterations of gains and losses, epigenetic events of promoter methylation appear to further undermine a destabilized genomic repertoire in squamous head and neck carcinoma (HNSCC). This chapter provides an overview of frequently methylated tumor suppressor genes in benign head and neck papillomas, primary HNSCC tumors, and HNSCC cell lines and their relevance as epigenetic markers in head and neck tumorigenesis.

Persistence of viral DNA in the epithelial basal layer suggests a model for papillomavirus latency following immune regression

Rabbit oral papillomavirus (ROPV) causes benign and spontaneously regressing oral lesions in rabbits, and is a useful model of disease associated with low-risk human papillomavirus types. Here we have adapted the ROPV system to study papillomavirus latency. Following lesion regression, ROPV DNA persists at the majority of regressed sites at levels substantially lower than those found in productive papillomas. Spliced viral transcripts were also detected. ROPV persistence in the absence of disease could be demonstrated for a year following infection and lesion-regression. This was not associated with completion of the virus life-cycle or new virion production, indicating that ROPV persists in a latent state. Using novel laser capture microdissection techniques, we could show that the site of latency is a subset of basal epithelial cells at sites of previous experimental infection. We hypothesize that these cells are epithelial stem cells and that reactivation of latency may be a source of recurrent disease.

Molecular characterization of late stomal recurrence following total laryngectomy

The goal was to determine recurrent or second primary status for late stomal malignancies, 16 and 17 years post-total laryngectomy in two laryngeal squamous cell carcinoma (LSCC) patients, based on DNA methylation signatures and HPV typing. Adopting a literature review based definition of late stomal recurrences as new primaries at the site of the stoma or neopharynx occurring >5 years after total laryngectomy, we employed a multi-gene candidate approach to examine promoter methylation in 24 tumor suppressor genes and PCR-based assays for HPV status offered additional insights into whether the late stomal tumors post-total laryngectomy were related or not. The primary tumor for Patient 1 was negative for HPV but had aberrant hypermethylation of APC, MLH1 and BRCA1. The stomal biopsy 17-years later showed presence of HPV-16 without any methylated genes. In Patient 2, HPV-11 and promoter methylation of APC identified in the primary tumor was also observed in the stomal malignancy 16 years post-total laryngectomy. Additional information provided by molecular typing for HPV and methylation markers underscored Patient 1's and 2's late stomal presentation as most likely a second primary and recurrence, respectively. DNA methylation markers are particularly advantageous because DNA methylation is an early event in tumorigenesis, and the epigenetic modification, 5-methylcytosine, is a stable marker. Molecular marks to discern genetic heterogeneity or relatedness of stomal malignancies several years post-total laryngectomy can provide clues to their status as either second primaries or likely recurrences. Our results support the hypothesis that a subset of stomal recurrences after total laryngectomy represents second primary tumors.

[Papillomas & laryngeal papillomatosis. Treatment with CO₂ laser surgery. Our experience over 15 years]

OBJECTIVES

The study goal was to evaluate the efficacy of CO₂ laser surgery in the treatment of laryngeal papillomatosis. We analysed several parameters such as gender, average age, relapse rate and viral serotype.

MATERIAL AND METHODS

A total of 26 diagnosed patients were included in this retrospective descriptive review. All of them were treated with CO₂ laser for laryngeal papillomas between 1995 and 2010.

RESULTS

This pathology was more prevalent in males (65.5%), with a slight predominance of a single larynx localisation over multiple lesion locations. Human papillomavirus (HPV) DNA was detected in 75.8% of the cases; genotypes 6 and 11 prevailed. Of the patients in this review, 44.8% relapsed; the relapse average was 2-3 episodes per patient. A total of 20.7% of cases were in remission (no relapse in the last 2 months); 34.5%, clearing (no apparent relapse in the last 3 years); and 41.3% in the healing stage (without relapse in the last 5 years). There was only one case that showed malignancy.

CONCLUSION

Papillomatosis is characterised as a pathology with an unpredictable course and with a low probability of malignancy. CO₂ laser surgery has meant a revolution in symptomatic treatment, but there is presently no curative treatment.

Pak1 and Pak2 are activated in recurrent respiratory papillomas, contributing to one pathway of Rac1-mediated COX-2 expression

Recurrent respiratory papillomas are premalignant tumors of the airway caused by human papillomaviruses (HPVs), primarily Types 6 and 11. We had reported that respiratory papillomas overexpress the epidermal growth factor receptor (EGFR), the small GTPase Rac1 and cyclooxygenase-2 (COX-2), and have enhanced nuclear factor-kappaB (NFkappaB) activation with decreased levels of IkappaB-beta but not IkappaB-alpha. We also showed that EGFR-activated Rac1 mediates expression of COX-2 through activation of p38 mitogen-activated protein kinase. We have now asked whether the p21-activated kinases Pak1 or Pak2 mediate activation of p38 by Rac1 in papilloma cells. Pak1 and Pak2 were constitutively activated in vivo in papilloma tissue compared with normal epithelium, and Rac1 siRNA reduced the level of both phospho-Pak1 and phospho-Pak2 in cultured papilloma cells. Reduction in Pak1 and Pak2 with siRNA decreased the COX-2 expression in papilloma cells, increased the levels of IkappaB-beta and reduced the nuclear localization of NF-kappaB, but had no effect on p38 phosphorylation. Our studies suggest that Rac1 --> Pak1/Pak2 --> NFkappaB is a separate pathway that contributes to the expression of COX-2 in HPV-induced papillomas, independently of the previously described Rac1 --> p38 --> COX-2 pathway.

Recurrent respiratory papillomatosis: a complex defect in immune responsiveness to human papillomavirus-6 and -11

Recurrent respiratory papillomatosis (RRP) is a rare disease of the larynx caused by infection with human papillomaviruses (HPV) -6 or -11, associated with significant morbidity and on occasion mortality. Here we summarize our current understanding of the permissive adaptive and innate responses made by patients with RRP that support chronic HPV infection and prevent immune clearance of these viruses. Furthermore, we provide new evidence of T(H)2-like polarization in papillomas and blood of patients with RRP, restricted CD4 and CD8 Vbeta repertoires, the effect of HPV-11 early protein E6 on T-cell alloreactivity, enriched Langerhans cell presence in papillomas, and evidence that natural killer cells are dysfunctional in RRP. We review the immunogenetic mechanisms that regulate the dysfunctional responses made by patients with RRP in response to HPV infection of the upper airway. In addition, we are identifying T-cell epitopes on HPV-11 early proteins, in the context of human leukocyte antigen (HLA) class II alleles enriched in RRP that should help generate a therapeutic vaccine. Taken together, RRP is a complex, multigene disease manifesting as a tissue and HPV-specific, immune deficiency that prevents effective clearance and/or control of HPV-6 and -11 infection.

Current concepts on human papillomavirus infections in children

Current evidence is strong enough to conclude that human papillomavirus (HPV) can be transmitted both sexually and non-sexually. The debate on HPV infections in children still continues but it is more focused on HPV prevalence than on transmission modes. HPV DNA detection in amniotic fluid, foetal membranes, cord blood and placental trophoblastic cells all suggest HPV infection in utero, i.e. prenatal transmission. Based on recent meta-analysis, vertical transmission occurs in approximately 20% of cases. Most of the mucosal HPV infections in infants are incident, persistent infections in oral and genital mucosa being found in less than 10% and 2% respectively. The mother seems to be the main transmitter of HPV to her newborn, but subsequent HPV infections are acquired horizontally via saliva or other contacts. Bimodal peak prevalence is seen for skin warts, oral papillomas and recurrent respiratory papillomatosis (RRP) in younger and older age groups, suggesting similar epidemiology. Of the clinical HPV diseases, juvenile-onset-RRP and genital condylomata are problematic; the former because of its life-threatening potential and the latter because of possible sexual abuse. HPV6 and 11 are the most common genotypes in both the lesions. Early in life, infections by the high-risk HPV genotypes may also remain persistent for a considerable period, and should be of considerable importance for HPV vaccination strategies.

Oropharyngeal cancer: a potential consequence of concomitant HPV and HIV infection

PURPOSE OF REVIEW

Oral human papillomavirus (HPV) infection is the principal cause of a distinct form of oropharyngeal cancer (OPCA) that has been rising in incidence in the United States since 1973, particularly among young men. The possible contribution of the HIV-epidemic to this increase is unclear.

RECENT FINDINGS

Incidence rates for HPV-related OPCA increased with age and were strongly influenced by year of birth in the United States (cohort effect). Persons with HIV/AIDS are at increased risk ( approximately two to six-fold) for OPCA relative to the general population. However, this excess risk may be attributable to tobacco smoking rather than the three-fold higher prevalence of oral HPV infection in this population. Consistent with a viral attribution, however, is the apparent increase in risk of OPCA with severity of AIDS-related immunosuppression. Analogous to other HPV-related cancers (e.g. cervical and anal cancer), trends over time do not appear to be influenced by highly active antiretroviral (HAART) therapy.

SUMMARY

Healthcare providers may encounter HPV-related OPCA more frequently among individuals with HIV/AIDS as this population ages and due to the strong birth cohort effects observed in the general population. However, there is no evidence in support of different incidence trends over time among persons with and without HIV/AIDS.