Antibodies to human papillomavirus type 5 are generated in epidermal repair processes

We reported previously that patients with psoriasis harbored at a very high frequency DNA sequences of the oncogenic human papillomavirus type 5 (HPV5) associated with epidermodysplasia verruciformis. Moreover anti-HPV5 antibodies were detected in 25% of the cases. Our aim was to find out whether keratinocyte hyperproliferation and/or autoimmunity could be responsible for HPV5 expression in psoriasis. We found that epidermal repair in patients with extensive second degree burns (n = 19) is frequently associated with the generation of anti-HPV5 antibodies. In patients with autoimmune bullous diseases (n = 118), a condition in which keratinocyte proliferation is involved in repair mechanisms, the prevalence of anti-HPV5 antibodies (15%-25%) was similar to that reported in psoriasis and significantly higher than that (5%) observed in individuals with no known history of human papillomavirus infection (n = 119). A high detection rate (57.9%) of HPV5 DNA was observed in patients with bullous diseases. Anti-HPV5 antibodies were found in patients with autoimmune connective tissue disorders with cutaneous involvement (n = 40) as frequently as in patients with bullous diseases. HPV5 DNA was detected in one of the 10 patients studied. In contrast, the prevalence of anti-HPV5 antibodies in patients with autoimmune neurological disorders (n = 47) and in patients with common warts (n = 28) or invasive carcinomas of the skin (n = 40) was as low as in the general population. It is worth stressing that a similar prevalence of antibodies against HPV1 was found in all groups studied. Our data strongly suggest that extensive keratinocyte proliferation is a major factor for the generation of anti-HPV5 antibodies and that autoimmunity may contribute to this phenomenon. It remains to be determined whether HPV5 and other human papillomavirus genotypes associated with epidermodysplasia verruciformis contribute to the hyperproliferation of keratinocytes occurring in epidermal repair and in psoriasis.