The ubiquity and type diversity of papillomaviruses in normal skin

Sammanfattning: Papillomaviruses are a diverse, epitheliotropic group of viruses. Some genotypes are the main cause of anogenital cancer in humans; others can induce skin lesions. In order to investigate the occurrence of subclinical skin infections with human papillomavirus (HPV), a pair of degenerate primers (FAP59/64) was designed. Moist cotton-tipped swabs were used as a gentle method of sample collection. Different skin sites were tried for sampling, and healthy and immunosuppressed adults and children of different age groups, new-borns included, were enrolled. Skin samples were also collected from healthy individuals from five countries in three different continents. All samples were tested for the presence of HPV DNA by PCR, and the positive samples were HPV type-determined by cloning and DNA sequencing. HPV DNA was found with high prevalence in both immunosuppressed (94%) and healthy (82%) individuals. The prevalence of HPV DNA was highest in samples collected from the more sun-exposed forehead, compared to legs and arms. The same high HPV prevalence was also seen in samples collected from different parts of the world. The study of children revealed that HPV colonisation of normal skin occurs very early in life and that acquisition of subclinical HPV infections probably starts soon after birth. Skin papillomaviruses could also be detected in a number of animal species. Altogether, a great number of different genotypes were found, 148 of which have been described for the first time. Papillomaviruses were found to be skin commensals with an impressive diversity of genotypes, both in humans and animals.