The virus of epidermodysplasia verruciformis: electron microscopic and fluorescent antibody studies.

Five cases of epidermodysplasia verruciformis were studied for viral particles and antigens. In all benign lesions tested, viral particles and antigens were observed by electron microscopy of ultrathin sections and/or tissue extracts and by fluorescent antibody staining with an antiserum against human wart virus. Both viral particles and antigens were observed in the cells of the stratum granulosum and the stratum corneum and not in those of deeper layers. Viral particles and antigens were observed in nuclei. Viral particles resembled morphologically the virus of common human warts. In two, one on the forehead and the other on the inner aspect of the upper thigh, of six lesions showing the histology of early malignancy, viral particles were observed by electron microscopy of ultrathin sections and/or tissue extracts. Four advanced malignant lesions, two primary ulcerated squamous cell carcinomas and two recurrent carcinomas, were similarly studied. In none of them, were viral particles or antigens detected. These results suggest that (1) the virus of epidermodysplasia verruciformis is related with that of common human warts both morphologically and antigenically, (2) at least some of the virus-induced lesions of epidermodysplasia verruciformis become malignant, and (3) when the lesions are completely replaced with malignant cells, neither viral particles nor antigens are recognizable in them.