Characterization of a new type of human papillomavirus (HPV) related to HPV5 from a case of actinic keratosis.

Human papillomavirus (HPV) DNA sequences, related to the genomes of HPVs associated with epidermodysplasia verruciformis (EV), were detected in DNA samples extracted from biopsied lesions in 2 of 24 cases of actinic keratosis found in the general population. An HPV DNA was molecularly cloned from one of these samples. Blot hybridization experiments, performed under stringent conditions, revealed a significant cross-hybridization only between this HPV DNA and the DNAs of HPV5 and of the HPV5-related types. The extent of homology between them ranged from 7 to 30%, as evaluated by hybridization in liquid phase at saturation followed by nuclease S1 analysis. This showed that the cloned HPV represented a new type, tentatively named HPV36. HPV36 was not found in the other 22 cases of actinic keratosis, but was detected in scrapings of benign lesions of 7 of 18 (39%) EV patients.