Recent polymerase chain reaction data have shown that most human papillomavirus (HPV) genotypes associated with epidermodysplasia verruciformis (EV) are widespread; however, HPV5 associated with EV skin carcinomas has only rarely been detected in non-EV patients. To identify the reservoir of this virus, we examined 335 sera from different groups of patients for the presence of HPV5 antibodies by an enzyme-linked immunosorbent assay test based on HPV5 virus-like particles. The prevalence of antibodies reacting with HPV5 virus-like particles was found to be significantly higher in psoriatic patients (24.5%) than in other groups (2–5%), including patients with atopic dermatitis and renal transplant recipients. Analysis of scrapings of lesional and uninvolved skin by a nested polymerase chain reaction method, using degenerate EV HPV primers, disclosed HPV DNA in 91.7% of 48 psoriatic skin samples and 35.5% of 31 atopic dermatitis specimens. Eleven EV HPV genotypes, most frequently HPV5 and HPV36, and a putative novel genotype (PsoX1) were identified in psoriasis. Five EV HPV genotypes and two putative novel genotypes (ADX1 and ADX2) were detected in atopic dermatitis patients. HPV5 was not found in atopic dermatitis patients. Using type specific primers, HPV5, HPV36, and HPV1 were found in 89.4%, 84.2%, and 42.1% of specimens from psoriatic patients, whereas HPV36 was detected in 22.5% of specimens from atopic dermatitis patients. HPV16 was never detected. On the whole, 27 HPV5 and 13 HPV36 DNA variants were disclosed after sequencing amplification products. Our data confirm that EV HPV are widespread and point to psoriasis as a reservoir for HPV5. Whether HPV5 is involved in the pathogenesis of psoriasis remains to be determined.
