Virus-like particles in papillomas of the human oral cavity

Human papillomavirus and oral disease - emerging evidence: a review

Human papillomavirus (HPV) infections have received considerable attention in recent years. Of the 120 or so known types of the virus, some cause a variety of benign wart-like lesions of the skin and genital and oral mucosae, whilst others are aetiologically associated with cervical and anogenital cancers. Recent epidemiologic evidence suggests that HPV may also be an independent risk factor for oropharyngeal cancer. In this context it has been suggested that HPV virus may modulate the process of carcinogenesis in some tobacco and alcohol induced oropharyngeal cancers and act as the primary oncogenic agent for inducing carcinogenesis among non-smokers. Dental practitioners have a major role in detecting all lesions of the oral mucosa caused, or possibly caused, by HPV. This paper briefly reviews the current state of knowledge of molecular and clinical aspects of HPV infections of the oral mucosa.

Epithelial dysplasia produced by carcinogen pretreatment and subsequent wounding

Golden hamsters in which the tongues were pretreated with DMBA for 4 weeks, subsequently excised, and either received no treatment or received additional postexcisional applications of acetone or DMBA for 9 to 13 days exhibited histologic evidence of epithelial dysplasia; these dysplastic lesions stained positive for papillomavirus genus-specific antigens. Conversely, animals in which the tongues received the same pretreatment yet had no excision failed to show any dysplastic changes, even though the tongues received additional applications of DMBA. Furthermore, papillomavirus genus-specific antigens were not demonstrable. The animals in which the tongues received no pretreatment with DMBA for 4 weeks followed by excisional wounding showed normal healing, even though the tongues were post-treated with DMBA. Papillomavirus genus-specific antigens could not be demonstrated in this last group.

A new type of human papillomavirus associated with oral focal epithelial hyperplasia

Lesions from 10 patients suffering from focal epithelial hyperplasia (FEH) of the oral mucosa, including those of 4 Greenlandic Eskimos, were investigated for the presence of human papillomavirus (HPV) DNA sequences by blot hybridization experiments. Two distinct HPVs were detected in the DNA extracted from these lesions, and their genomes were molecularly cloned and characterized. One of these HPVs, detected in 4 patients, was found to be identical with HPV13, whose association with FEH was already known. The other one, detected in 6 patients, was only weakly related to HPV13 and to the other HPVs associated with lesions of the mucous membranes, and constituted a new HPV type, tentatively named HPV32. Lesions from other types of oral papillomas, obtained from 14 additional patients, were also analyzed. Human papillomavirus DNA sequences were detected in the DNA preparations extracted from 5 specimens: HPV6 DNA in a condyloma and in a papilloma, 2 as yet uncharacterized HPV DNAs in 2 papillomas, and HPV32 DNA in a papilloma which showed histologic similarities to FEH. Thus, it seems likely that FEH of the oral mucosa is a disease associated with 2 specific HPVs--HPV13 and HPV32.

Peroxidase-antiperoxidase evaluation of human oral squamous cell papillomas

In human beings, the viral origin of condylomatous lesions of the mouth and cervix, multiple papillomas, and verruca vulgaris of the larynx has been established. The viral origin of papillomatosis in rabbits and dogs has also been documented. The literature, however, shows no conclusive evidence of a viral origin of human oral squamous cell papillomas (SCP). The purpose of this study was to use the peroxidase-antiperoxidase (PAP) staining technique to determine whether human papillomavirus (HPV) antigens exist in serial step sections of human oral SCP. Fifty human oral SCPs were randomly selected from the department files, and tissue sections were subjected to an indirect immunoperoxidase-PAP technique. Evidence of HPV-Type I virus antigens was found in 2 of 50 papillomas studied (2 of 194 tissue sections). This suggests that all oral SCPs are not of viral antigen.

Detection of papillomavirus DNA in oral papillomas and carcinomas: application of in situ hybridization with biotinylated HPV 16 probes

Four oral papillomas and 7 carcinomas were studied for the presence of HPV DNA by means of in situ hybridization. Hybridization was carried out with a HPV 16 probe labelled with biotin under different conditions (nick translation/photobiotin). Subsequently, a modified biotin-avidin-alkaline phosphatase procedure was used to visualize virus infected cells. Four/4 papillomas and 4/7 carcinomas were seen to contain HPV harbouring cells. Positive cells were located at intermediate and superficial cell layers in papillomas and in keratinized zones in carcinomas. Analogous results were found with nick translated and photobiotinylated probes. DNA-biotinylation in conjunction with the biotin-avidin-alkaline phosphatase detection system proved to be a sensitive, convenient and rapid modification of in situ hybridization.

Papillomaviruses: their possible role in oral disease

Papillomaviruses are ubiquitous DNA viruses that are epitheliotropic and produce a range of epithelial neoplasms, both benign and malignant, in animals and man. Human papillomaviruses are associated with a variety of rare and uncommon oral lesions, and there has been increasing suspicion that they may be implicated also in some premalignant and malignant oral lesions.

Analysis of oral papillomas, leukoplakias, and invasive carcinomas for human papillomavirus type related DNA

Five papillomas, five leukoplakias, and six carcinomas were investigated for the presence of papillomavirus group-specific antigens and viral DNA. Viral proteins were identified with genus-specific papillomavirus antibodies. Cloned human papillomavirus (HPV) 11 and 16 DNA were used as probes in Southern blot hybridization at conditions of different stringency in order to determine viral DNA. Four of five papillomas, four of five leukoplakias, and three of six carcinomas reacted with HPV DNA probes and revealed some stained cells after exposure to HPV antibodies. HPV type 16 was found in one carcinoma and HPV type 11 was demonstrated in another case of carcinoma.

Oral "hairy" leucoplakia in male homosexuals: evidence of association with both papillomavirus and a herpes-group virus

An outbreak of a new form of oral leucoplakia, found principally on the lateral borders of the tongue, is reported in male homosexuals in the San Francisco area. Many of the patients showed evidence of immunosuppression, and candida was often found in the lesions. The characteristic histology is similar to that of the flat wart of skin. There was immunocytochemical evidence of papillomavirus core antigen in 77% of 30 biopsy specimens, but no papillomaviruses were detected by electron microscopy in samples from 6 randomly selected patients. In 5 of these 6 patients there was evidence of a herpes-type virus. Pneumocystis carinii pneumonia has developed in 8 of 37 patients in a 33-month period. This leucoplakia may presage AIDS, may be associated with both papillomavirus and a herpes-type virus, and may offer clues to the pathogenesis of other forms of oral epithelial hyperplasia and dysplasia.

Occurrence of papillomavirus structural antigens in oral papillomas and leukoplakias

Six oral papillomas and 7 oral leukoplakias were studied with genus-specific antibodies against detergent-disrupted papillomaviruses. Indirect immunofluorescence staining was applied to frozen sections. Distinct nuclear staining of superficial keratinocytes was seen in 5 of 6 oral papillomas, 2 of 5 homogenous leukoplakias, and in 2 cases of nodular leukoplakia, one of these showing transition into an invasive carcinoma. Papillomavirus antibodies offer a new way to detect and localize papillomaviruses in epithelial hyperplasias. The relevance of the immunomorphological identification of papillomavirus-associated antigens is discussed with special reference to the molecular hybridization technique.

Oral condyloma accuminatum. A light and electron microscopic study

In 2 cases with clinical and histopathological features of oral condyloma accuminatum, virus-like particles were identified both in the cell nuclei and the cell cytoplasm. We are concerned here with etiological factors and with differential diagnostic problems related to these extremely rare oral lesions.

Ultrastructural studies of intraoral verruca vulgaris

The literature offers conflicting views regarding the existence of verruca vulgaris in the oral cavity. In an attempt to clarify this issue, a series of ten oral lesions which had been diagnosed as verruca vulgaris and ten oral lesions diagnosed as squamous-cell papilloma were examined ultrastructurally. Six of the lesions diagnosed as verruca vulgaris contained the characteristic intranuclear viral particles which are normally found in that lesion. None of the lesions diagnosed as squamous-cell papilloma exhibited this type of intranuclear viral inclusions.

Focal epithelial hyperplasia in a group of South Africans: Its ultrastructural features

Electron microscopic observation of samples of tissues from lesions diagnosed as focal epithelial hyperplasia revealed the presence of viral particles in six (possibly seven) of 13 cases examined. Viral particles were intranuclear and varied from sparsely scattered to densely packed. A crystalline arrangement was present in one case. The chromatin of affected cells was typically condensed into clumps and thick bands, and the nuclear membrane was usually absent in pronounced cases. The nuclei of the basal and prickle cells were frequently indented and the chromatin peripherally condensed. Numbers of lysosomal-like organelles were observed in many of these cells. The ballooning epithelial cells with their mitosis-like aberrations observed with light microscopy consisted of a rim of tonofilaments and organelles and a homogeneous granular center interspersed with dense areas. It is suggested that the nuclear characteristics and numerous lysosomes observed in basal and prickle cells are cellular changes induced by the viral infection and that the mitosis-like aberrations represent a bizarre and arrested form of mitosis.

Ultrastructural features of human juvenile laryngeal papillomas

The ultrastructural organization of 12 juvenile laryngeal papillomas was investigated. Four patients were more than 40 years old but had carried the disease since childhood. The other 8 patients were 2-10 years old and had carried the disease from 1-5 years. There is regularly observed a discontinuity of the basement membrane and the basal cells of ten exhibit abundant cytoplasmic processes. In the stratum spinosum there is often found glycogen-like inclusions as well as Odland bodies and keratohyalin granules. In the superficial layers there are nuclear remnants as in parakeratosis. Virus-like particles of a diameter around 330 A have been demonstrated in a disintegrated superficial cell. The scarcity of such particles is discussed with possible regard to a transformation occurring in the superficial layers of the papilloma and to the high shedding rate of the surface cells.

Serological studies with human papova (wart) virus

Methods for demonstrating antibody to wart virus by complement fixation and passive haemagglutination tests are described and compared with the precipitin test of Almeida & Goffe (1965). The results reveal the much greater sensitivity of the passive haemagglutination method, particularly in the detection of the immunoglobulin M class of antibody. Both complement-fixing and precipitating antibody were detected in sera from patients whose warts had undergone a spontaneous resolution.The presence of antibody to wart virus was demonstrated in sera from persons who had had warts up to 10 years previously, and in a few cases from those who thought they had never had warts.The antigenic identity of virus from hand warts and plantar warts of the simple and mosaic types was revealed, and some evidence was obtained for similar identity of the virus from genital warts.

The extracellular antigens of Micropolyspora faeni: their significance in farmer's lung disease

A serological analysis of the extracellular antigens of Micropolyspora faeni by immunodiffusion with a combination of sera revealed 29 individual antigens. A survey was made of the incidence of precipitins to the antigens in sera from patients with clinical farmer's lung disease (FLD) and other respiratory diseases. Precipitating antibody was found in 75% of farmer's lung cases and in 20% of other cases who had been exposed to the same environment. More precipitin reactions were seen in sera from severe forms of FLD than from milder forms. The distribution of precipitins to individual antigens was not significantly affected by severity of disease.Most of the patients with precipitins to M. faeni, but without the symptoms of FLD, were suffering from mild or moderate symptoms of other respiratory diseases with a history of chronic onset of symptoms. The distribution of precipitins to individual antigens in this group was similar to that in clinical FLD patients but the incidence was considerably lower.The significance of these results is discussed.