Phylogenetic analysis of the human papillomavirus type 2 (HPV-2), HPV- 27, and HPV-57 group, which is associated with common warts

Abstract

Human papillomavirus types 2 (HPV-2), HPV-27, and HPV-57, are three closely related viruses within the phylogenetic supergroup formed by the remotely related genital papillomaviruses. In contrast to this phylogenetic association, these three viruses are most often found in common warts at nongenital sites, but also occasionally in genital warts and mucosal lesions of the nasopharyngeal cavity. We studied the genomic diversity of HPV sequences in skin warts presumably caused by these viruses. These biopsies were sampled from 75 patients living in Germany, Japan, or Singapore. Among 27 warts with HPV-2, we found seven new genomic variants and among 32 with HPV-57, eight new variants. In both cases, we did not detect the original prototype genomes. In contrast, 13 of 16 warts with HPV-27 contained the prototype genome, and only one new variant was found in three patients. We did not find variants clearly intermediate between any two types, although HPV-2 and HPV-27 are among the most closely related of the extent HPV types. We also did not detect novel HPV types, although the samples were examined with polymerase chain reaction protocols that would have detected remotely related HPVs. So we propose that the phylogenetic group formed by HPV-2, HPV- 27, and HPV-57 has no or only very rare additional members. One of the HPV- 57 variants found, HPV-57-G44, was most likely identical to the subtype HPV- 57b, previously proposed to be associated with nasal neoplasia, but found here frequently in common skin warts. Our publication establishes a foundation for pathological and phylogenetic comparisons of HPV types in skin warts.