Background Human papillomaviruses (HPVs) of the beta genus (β-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 β-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 β-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 β-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.