Patients with psoriasis treated with psoralen–UV-A (PUVA) are at increased risk of skin cancer ; however, the exact causes of this increasedincidence are not well understood. It has been suggested that PUVA may increase expression of the tumorigenic agent human papillomavirus (HPV) in skin bydirectly stimulating virus replication, immune suppression, or both, thereby leading to skin cancer formation.
To determine whether HPV DNA prevalence in the skin is increased after long-term PUVA treatment.
Screening for the presence of HPV sequences in DNA isolated from plucked body hairs of patients with psoriasis with a history of PUVA exposure anda history of skin cancer (group A), PUVA exposure and no history of skin cancer(group B), and no PUVA exposure and no history of skin cancer (group C).
Patients and Methods
Hair samples were obtained from 81 patients with psoriasis (56 men and 25 women; mean age, 52 years), including 16 in group A (mean number of PUVAexposures, 702), 35 in group B (mean number of PUVA exposures, 282), and 30 in group C. DNA was isolated from the hair samples and analyzed by polymerasechain reaction with the use of 2 nested primer systems specific for epidermodysplasia verruciformis–associated or related and genital or mucosal virus types,respectively.
The rate of HPV DNA positivity was significantly higher in groups A (73% [11/15]) and B (69% [24/35]) than in group C (36% [10/28]) (A + B vsC, P = .009; χ2 test; age adjusted).
The prevalence of HPV in the skin (hair follicles) is increased in patients with psoriasis who have a history of PUVA exposure.