Abstract
BACKGROUND: Human papillomaviruses (HPVs) of the beta genus (beta-PV), especially HPV5 and HPV36, are proposed to play a pathogenic role in psoriasis, but many previous studies have failed to control for potential confounders, including treatment. OBJECTIVES: To re-examine the relationship between beta-PV and psoriasis addressing limitations present in previous studies and analyse intra-patient concordance for carriage of HPV. METHODS: Plucked eyebrow hairs and forearm skin scrapes were collected from 20 newly diagnosed, previously untreated adult patients with psoriasis and 23 normal controls. A combination of type-specific and degenerate polymerase chain reaction methods was used to achieve comprehensive HPV DNA detection. RESULTS: The prevalence of HPV in hair and skin from psoriasis patients was higher than in controls (83.3% vs. 46.7%, respectively, P < 0.03 corrected for age and clustering). HPV5 or HPV36 were not over-represented. The profile of diverse beta-PV types was comparable in the two groups. Intra-patient concordance for HPV DNA at separate sites was high (P < 0.00001). CONCLUSIONS: Our data do not support a specific causal role for HPV5 or HPV36 in psoriasis, but suggest that psoriatic skin may be more permissive for viral presence than normal skin. High intra-patient concordance for specific HPV types at separate sites, together with the ubiquity of HPV DNA in normal human skin, suggests that an individual becomes colonized with a particular beta-PV profile presumably to the exclusion of other types. To what extent this HPV profile is then causal in the subsequent development of hyperproliferative skin disease is unknown.