Virus-like particles and inclusion bodies in skin papillomas

History of human papillomavirus, warts and cancer: what do we know today?

Human papillomavirus has been a cause of infection in humans for thousands of years. The history of papillomaviruses, knowledge of their causative role in benign and malignant disease, and their structural characteristics have led to the development of vaccines to prevent cervical and anogenital cancers. Many questions remain unanswered before HPV vaccines can be optimised; however, the concept of virtual eradication of cervical cancer is not impossible, and remains a realistic aspiration.

Tumour virology--history, status and future challenges

Viruses enter host cells in order to complete their life cycles and have evolved to exploit host cell structures, regulatory factors and mechanisms. The virus and host cell interactions have consequences at multiple levels, spanning from evolution through disease to models and tools for scientific discovery and treatment. Virus-induced human cancers arise after a long duration of time and are monoclonal or oligoclonal in origin. Cancer is therefore a side effect rather than an essential part of viral infections in humans. Still, 15-20% of all human cancers are caused by viruses. A review of tumour virology shows its close integration in cancer research. Viral tools and experimental models have been indispensible for the progress of molecular biology. In particular, retroviruses and DNA tumour viruses have played major roles in our present understanding of the molecular biology of both viruses and the host. Recently, additional complex relationships due to virus and host co-evolution have appeared and may lead to a further understanding of the overall regulation of gene expression programmes in cancer.

New types of human papillomaviruses and intracytoplasmic inclusion bodies: a classification of inclusion warts according to clinical features, histology and associated HPV types

Two new types of intracytoplasmic inclusion bodies (ICBs) associated with distinct clinical features, and the presence of DNA of distinct types of human papillomaviruses (HPVs) are reported. One hundred and seven cutaneous warts containing ICBs were grouped into three categories according to distinct clinicopathological features: 67 were wart lesions with well-known granular (Gr)-ICB, 13 were punctate keratotic lesions with filamentous (Fl)-ICB and 31 were pigmented warts with homogeneous (Hg)-ICB. Molecular biological studies were performed in order to assess a specific association of each group of warts with distinct types of HPV. HPV-1 DNA sequences were detected in all the lesions with a Gr-ICB. Punctate keratotic lesions with Fl-ICB were associated with HPV-63, which was newly cloned from such a lesion. One of the samples also contained HPV-1 DNA. Pigmented warts with Hg-ICBs contained one of the related HPVs, i.e. HPV-4, HPV-60 or a novel type of HPV, HPV-65. Based on these associations, a classification of inclusion warts is proposed.

Varied clinical morphology of HPV-1-induced warts, depending on anatomical factors

The clinical and histological features of 49 lesions induced by human papillomavirus type 1 (HPV-1) were studied. The majority of cases showed the typical clinical features and location of such lesions. They were usually located on the ventral or lateral surfaces of the hands or feet, and were dome-shaped lesions with a central depression. However, HPV-1-induced lesions located on other body areas displayed different clinical features, such as those of common warts, a digitate wart, and a cutaneous horn. One lesion on a healing burn scar had a herpes-like appearance. As these 49 lesions were induced by the same type of HPV (HPV-1), differences in their clinical features are likely to have been due to host-related factors.

Plantar warts

Plantar warts are an extremely common problem which can be very painful and debilitating. As is often the case with common problems, the knowledge of the disease and its treatments is inversely proportional to the frequency of the disease. Often the lay person knows as much and has as strong an opinion on treatment as the treating physician. In addition, most communities have someone who has the reputation of being able to bewitch warts off. This review will attempt to make some order of myriad facts and suppositions regarding this infection. Hopefully, this will aid the physician in the diagnosis and treatment of the patient with plantar warts.

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.

Correlative studies of Verruca vulgaris by H & E, PAP immunostaining, and electronmicroscopy

Twenty-one specimens of Verruca vulgaris were used for an investigation to define what portion of the papillomatous structures seen in H & E stain will correspond to the areas of positive staining for papilloma virus antigen utilizing the peroxidase-antiperoxidase immunostaining technique. Vacuolar spaces filled with thready material and large ovoid parakeratotic cells seen in H & E stain stained positively for papilloma virus antigen. In the granular layer, viral antigens stained heavily, the nuclei of cells showing koilocytosis. Both round and irregularly shaped kerathohyaline granules did not stain positively for viral antigen stain. Eight of the 21 specimens showed marked positivity for papilloma virus antigen. Three other cases were positive in only focal sites. Of the 8 immunostained-positive selected cases used for ultrastructural studies, only 2 showed the viral particles. The study suggests that the PAP immunostaining is a more sensitive and yet less cumbersome method than electronmicroscopy for demonstration of papilloma virus.

[Light-microscopic study of classified virus warts (HPV-1 and HPV-4) (author's transl)]

Histological investigations of verrucae vulgares of the hand and of plantar warts show striking differences between HPV-1-induced warts and those caused by the virus type HPV-4. In warts caused by HPV-1 massive vacuolization and disturbance of epidermal cell differentiation through the entire thickness of the epidermis is predominant whereas in HPV-4 stimulated warts cell differentiation is impaired to a much lesser degree. Despite the presence of inclusions and of vacuolized cells a thick stratum granulosum and a compact horny layer are formed in the latter type.

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.

[Comparison of the epidermodysplasia verruciformis Lewandowsky-Lutz with the other Papova virus acanthomas by light and electron microscopy (author's transl)]

Based on histology and electron microscopy, a series of Papova virus acanthomas consisting of 300 common warts and Condylomata acuminata as well as primary efflorescences of 7 typical and 7 questionable cases of Epidermodysplasia verruciformis have been classified. Four cytological types expressing different cytopathogenic viral actions were established. Typ 4 ("basophilic foamy giant keratinocytes") seems to be specific for Epidermodysplasia verruciformis which thus can be differentiated histologically against ordinary warts (type 1-3).

The morphology of human papillomas of the upper respiratory tract

Recurrent squamous papillomas of the upper respiratory tract were examined by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Surface of the cells is irregular and is covered by numerous stout microvilli. These are shorter and broader than those of cells of the uninvolved mucosa. The villi often seem umbilicated at the apex; the remainder of them, however, are rounded. The epithelium participating in the formation of papillomas shows some maturation of the cells but this does not progress normally. The predominating area is the thickened spinous layer representing the bulk of the lesion. The basal layer shows mildly increased activity but the basement membrane is intact. The cells often are very closely packed but in some areas, more particularly in the deep layer, they are loosely arranged. The intercellular space contains a moderately electron-dense finely fibrillar material. No abnormal mitoses are found. The neighboring univolved epithelium often shows increased growth activity and some inflammation. The larygneal papillomas propably represent an overgrowth of epithelium which may develop following hindered desquamation caused and/or heralded by a chronic inflammatory condition probably of viral origin and may be preceded by epithelial metaplasia and hyperplasia.

[Electron optical determination of the virus of the condyloma acuminatum]

Es wird über elektronenmikroskopische Untersuchungen an spitzen Condylomen im Bereich des weiblichen Genitale berichtet, in denen der Nachweis von Viruspartikeln im Cytoplasma der Epithelzellen erbracht werden konnte. Größe, Lokalisation und Mikromorphologie der gefundenen Elementarkörperchen machen wahrscheinlich, daß der Erreger der spitzen Condylome nicht mit dem der Verrucae vulgares identisch ist.

Human papova (wart) virus

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Human Wart Virus: In vitro Cultivation

Inoculation of cell cultures of fetal skin of human and murine origin with virus extracted from human wart tissue resulted in the appearance of intracellular wart virus specific antigen, as demonstrated by fluorescent antibody techniques. Appearance of antigen was accompanied by cytopathogenicity and the accumulation of large numbers of characteristic virus particles.

A cytological and cytochemical investigation of the development of the viral papilloma of human skin

The morphological appearances and some tinctorial properties of the cells of the infectious (viral) papilloma of human skin are described. Pathological alterations of the nuclei of affected cells occur in a definite sequence of stages. In the earliest, and acidophilic Feulgen-negative intranuclear inclusion body is recognizable. Subsequently the inclusion body and nucleus enlarge, there is progressive disorganization of nuclear structure, and the inclusion body then becomes basophilic and stains with the Feulgen reaction. The nucleus finally disappears, leaving the inclusion body in the cell remnant. The relative amounts of Feulgen-colored DNA per cell at each stage in the evolution of the lesion in the infected cells, as well as in normal appearing and hypertrophic cells of the papilloma, were measured microphotometrically in Feulgen preparations. Determinations were made using the "plug" and "two wave length" methods. These are compared with measurements of DNA in cells of the basal and spinous layers of normal human skin. The frequency distribution curves of relative amount of DNA in cells of normal skin, and normal-appearing cells in hyperplastic epithelium, show the bimodal diploid and tetraploid peaks characteristic of growing tissues. Infection of the epidermal cell entails prompt synthesis of DNA in the nucleus. Increased amounts of DNA (tetraploid to 16 ploid levels) are found in the earliest recognizable cytopathological stages of infection and do not increase appreciably during the subsequent evolution of the cellular lesion. At a relatively late stage, all the cellular DNA is relocated ("transferred" or "reassembled") in the inclusion body, and is not further significantly increased in amount. Active formation of DNA in affected cells appears, from these measurements, to occur only in relatively intact nuclei. The inclusion bodies of infected cells are found to contain a relatively basic protein which stains with the alkaline-fast green method for histone.