Two novel types of human papillomavirus, HPV 63 and HPV 65: comparisons of their clinical and histological features and DNA sequences to other HPV types.

An association exists between verrucae presenting with specific histological features and the type of HPV inducing the lesion. An HPV 1 induced lesion is associated with a granular type of intracytoplasmic inclusion body (Gr-ICB), whereas HPV 4 is associated with the homogeneous type of ICB (Hg-ICB). A third type of inclusion body, a filamentous type (F1-ICB), was found to be present in multiple punctate keratotic lesions. A novel type of papillomavirus, HPV 63, was present in such lesions. After cloning, characterization and sequencing of its DNA genome, HPV 63, although still very distinct (< 66% nucleotide homology), could be grouped with HPV 1. Upon histological examination of verrucous lesions presenting clinically with grey to black pigmentation, the Hg-ICB present were very characteristic. These lesions were infected with HPV 4, HPV 60, or HPV 65. The majority of the lesions contained the novel type HPV 65. This viral DNA was isolated and characterized. Its DNA sequence has an 83% homology to that of HPV 4, whereas both are more distantly related to HPV 60, an HPV isolated from an epidermoid cyst.