Demonstration of papillomavirus antigen in paraffin sections of laryngeal papillomas

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.

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.

Human Fibroblast Interferon Adjuvant to CO2 Laser in the Treatment of Recurrent Juvenile Laryngeal Papillomatosis: Experience with 7 Cases

Preliminary results of adjuvant human fibroblasts interferon (IFN beta) given after CO2 laser excision in recurrent laryngeal papillomatosis in 7 adult patients are reported. Diagnostic procedure included histologic and immunohistochemical investigations to demonstrate the presence of viral cytopathic effect and for characterization of the virus. All patients underwent CO2 laser excision under general anesthesia followed by administration of IFN beta intramuscularly at the dose of 4x106 IU/day for 10 consecutive days. In the presence of complete remission, patients were followed without further therapy; in the presence of partial remission, a new combined treatment was established. All patients had a complete remission after combined treatment, but 4 subsequently developed recurrences. Treatments were always well tolerated; even cirrhotic patients showed no side effects.

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.

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.

Characterization of human papillomavirus in airway papillomas by histologic and biochemical analysis

The role of human papillomavirus (HPV) in airway papillomas has been well defined in recent literature. The chronicity and recurrence of papillomas has been postulated to be a result of residual viral genome in tissue treated with standard laser techniques. Thirteen patients with airway papillomas were selected for study with polymerase chain reaction (PCR) methods to detect viral DNA. Specimens taken prior to laser therapy and specimens taken at laser margins were consistently positive for HPV DNA by PCR. The HPV DNA is apparently present in tissues after macroscopic disease has been ablated by laser techniques. Histologic analysis of laser biopsies demonstrated fragments of squamous epithelium with cytologic features of HPV infection. Laser treatment is ineffective in eradicating HPV-infected tissues from airway papillomas, and this finding supports the notion that recurrence is a product of HPV incorporated into tissue not ablated by laser irradiation. Specific methods, results, and clinical correlation will be discussed.

Recurrent respiratory papillomatosis

Juvenile-onset recurrent respiratory papillomatosis is a vertically transmitted disease caused by members of the human papilloma virus family. Characterized by the relentless growth of papillomatous lesions of the larynx, recurrent respiratory papillomatosis imposes significant morbidity on patients and strain on their families. Surgical excision of the papillomata remains the mainstay of therapy, but human papilloma virus DNA persists in adjacent, normal-appearing mucosa and likely serves as a reservoir for viral reseeding. Despite multiple adjuvant treatment modalities, a cure for recurrent respiratory papillomatosis remains elusive. Most afflicted patients eventually enter spontaneous remission, but some endure several hundred surgical procedures before this welcome respite.

Antibody response to a synthetic peptide derived from the human papillomavirus type 6/11 L2 protein in recurrent respiratory papillomatosis: correlation between Southern blot hybridization, polymerase chain reaction, and serology

Recurrent respiratory papillomatosis (RRP) is the most common benign tumour of the larynx, affecting both children and adults. We present a series of 25 patients, including 10 cases of juvenile multiple, 8 cases of adult solitary, and 7 cases of adult multiple RRP. Biopsy tissue from each patient was screened by Southern blot hybridization and polymerase chain reaction for the presence of human papillomavirus (HPV) DNA. Sera from patients and age- and sex-matched controls were tested for the presence of HPV-specific antibodies using a synthetic peptide derived from the minor capsid protein (L2) of HPV 6/11. By Southern blot hybridization and/or polymerase chain reaction, biopsies from all patients were positive for HPV 6/11 DNA. There was no difference in antibody response between cases and controls. Female cases and controls had significantly higher antibody titers than male subjects. A correlation was observed between the HPV-specific antibody level and the number of surgery-necessitating recurrences.

Human papillomavirus 6, 11, and 16 in laryngeal papillomas

Twenty-seven cases of benign laryngeal papillomas, both single and multiple variants, were analysed for human papillomavirus (HPV) by DNA slot-blot hybridization chiefly to determine the pattern of infection in Hong Kong Chinese. DNA was extracted from paraffin blocks of formalin-fixed tissue and probed separately for HPV 6, 11, 16, and 18. Sixteen cases (59 per cent) showed the presence of at least one of these four HPV genomes. Thirteen cases (48 per cent) were positive for HPV 11 only. Three other cases (11 per cent) showed triple positivity for HPV 6, 11, and 16. None were positive for HPV 18. The predominance of HPV 11 infection contrasts with other series which have shown either an almost equal distribution of HPV 6 and 11 or a predominance of HPV 6. The finding of HPV 16 in three cases was unexpected. Using the polymerase chain reaction (PCR) with primers complementary to the upstream regulatory region of the HPV 16 viral DNA, the presence of HPV 16 genome was confirmed in all three cases. As the number of HPV 16-positive cases in this study is small, analysis of more cases using fresh biopsy material and a wider range of HPV type-specific PCR primers is warranted to determine the relative incidence of HPV subtypes in these benign laryngeal papillomas.

Laryngeal papillomatosis: correlation between severity of disease and presence of HPV 6 and 11 detected by in situ DNA hybridisation

A technique using a biotin-streptavidin polyalkaline phosphatase complex was applied to routinely fixed and processed biopsy specimens of laryngeal papillomata from 45 patients taken over the past 20 years to detect human papilloma virus (HPV) types 6 and 11. Two thirds of both adult and juvenile onset cases were positive for HPV 6 or HPV 11 or both. Five specimens of normal vocal cord epithelium were negative for HPV 6 and 11. The detailed clinical history, endoscopic findings, success of treatment and eventual prognosis were compared with the HPV state of biopsy material for each patient. Patients with multiple confluent lesions when first seen, whose histology showed florid koilocytosis and who had strongly positive reactivity for HPV 6 or 11 present in the surface epithelial cell nuclei, had a poor prognosis requiring multiple endoscopies to control their disease.

Tracheotomy in children with recurrent respiratory papillomatosis

Fifty-eight patients with laryngeal papillomatosis were managed at Children's Hospital Medical Center, Cincinnati, OH, between January 1978 and December 1987. Twelve of these patients (21%) had tracheotomies. A retrospective review of these 12 cases was undertaken to determine the incidence, pattern, timing, and clinical risk factors for tracheal spread after tracheotomy. Six of 12 patients (50%) developed tracheal papillomas after tracheotomy. Peristomal mucosa was consistently the site of initial involvement followed by progressive distal spread along the length of the tracheotomy tube. Stomal involvement followed tracheotomy by an average of 14 weeks, occurring as early as 7 weeks postoperatively. Mid-tracheal spread followed stomal involvement by an average of 10 weeks. Risk factors for tracheal spread included the presence of subglottic disease at the time of tracheotomy and prolonged cannulation. Whenever possible, tracheotomy should be avoided in patients with recurrent respiratory papillomatosis. When unavoidable, every effort should be made to keep the duration of cannulation as short as possible.

Demonstration of human papillomavirus types 6 and 11 in juvenile laryngeal papillomatosis by in-situ DNA hybridization

A study is reported in which an in situ hybridization technique for the demonstration of human papillomavirus (HPV) employing a biotin--streptavidin polyalkaline phosphatase complex has been successfully applied to formalin-fixed paraffin-processed tissue obtained from ten patients with juvenile laryngeal papillomatosis. In all cases, positive results were obtained for either HPV type 6 or 11. Normal vocal cord epithelium was negative.

Juvenile laryngeal papillomatosis

From the records of 23 patients with juvenile laryngeal papillomatosis, various aspects of the aetiology, natural history and treatment of the condition have been presented. The lesions are thought to be viral in origin, they are notoriously unpredictable in their behaviour, and treatment can often be prolonged and frustrating. Tracheostomy should be avoided, if possible, owing to the risk of further dissemination down the trachea and bronchi. The CO2 laser now seems to be the surgical treatment of choice, and early reports of adjuvant interferon therapy are encouraging. However, the laser is only available in certain centres, and interferon supplies are limited at present.

Immunoperoxidase localization of papillomavirus antigen in cutaneous warts and bowenoid papulosis

Using the immunoperoxidase technique and a broadly cross-reactive antiserum which detects infection with any papillomavirus, papillomavirus capsid antigen was demonstrated in 25 of 48 cutaneous papillomas and in two of 38 cutaneous dysplasias. Both positive dysplastic lesions were diagnosed on histopathologic examination as bowenoid papulosis. Antigen-positive cutaneous warts were scattered in all age categories and at all body sites. In addition, there was little variation in antigen expression by morphologic type of wart. Antigen was localized in the nucleus of superficial epithelial cells. The amount of staining was variable, with some warts showing large numbers of stained nuclei. In other warts only isolated cells stained. In both cases of bowenoid papulosis, small foci of positively stained cells were observed. The finding of papillomavirus antigen in two of 21 cases of bowenoid papulosis is suggestive of an etiologic relationship between this lesion and a papillomavirus. An examination of antigen-negative cases of bowenoid papulosis for a papillomavirus genome will be necessary to confirm these results.

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

Juvenile- and adult-onset laryngeal papillomas were examined for the presence of a human papillomavirus (HPV) genome and capsid antigens. DNA was isolated from a portion of tissue removed for therapeutic purposes, and the presence of a papillomavirus genome was detected by Southern transfer analysis. The viral DNA found in the 12 juvenile-onset and the 8 adult-onset laryngeal papillomas examined was identified as HPV-6 on the basis of size, restriction endonuclease digestion patterns, and homology detected under stringent conditions. Restriction endonuclease analysis of the viral genomes revealed at least four different subtypes, designated HPV-6c through HPV-6f. The most common subtype, HPV-6c, was detected in over half of the papillomas studied, including both juvenile and adult types. The remaining tissue was fixed and processed for immunocytochemistry. The immunoperoxidase technique was used with an antiserum that reacts with capsid antigen(s) common to all HPV serotypes. HPV antigen was found in two of the juvenile-onset papillomas and two of the adult-onset papillomas. The antigen was localized to the nucleus and was distributed in the superficial layers of the epithelium. HPV capsid antigen had not previously been detected in cases of adult-onset papilloma, and the HPV genome in both juvenile- and adult-onset laryngeal papillomas had not been characterized. Despite the absence of detectable viral antigen in most of the specimens examined, the presence of the HPV genome provides strong evidence for the papillomavirus etiology of these tumors.