Human papilloma virus

• Human papillomaviruses (HPVs) are a large group of approximately 100 genotypes of DNA tumor viruses that infect the epithelia of skin or mucosa and most commonly cause benign papillomas or warts 
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• Infection of the skin by a distinct subset of HPV types induces common or flat warts 
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• Epidermodysplasia verruciformis (EV) is an inherited disease characterized by generalized flat warts or pityriasis versicolor-like macules, caused by chronic infection with EV-specific HPV types 
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• EV types of HPV are detected in skin cancers and normal skin. These viruses are activated by UV exposure, immunosuppression, and specific host genetic background (EV) 
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• Anogenital infection with HPV is a highly prevalent, sexually transmitted infection (STI) seen predominantly in young adults. Condylomata acuminata or benign anogenital warts are typically caused by HPV-6 or -11, which are considered to be low-risk types.

• Persistent infection with high-risk HPV types, predominantly HPV- 16 and -18, is the major cause of cervical cancers, and a subset of vaginal, vulvar, penile, anal, and oropharyngeal neoplasias 
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• Patients with cellular immunodeficiencies are at higher risk for persistent HPV infection and progressive disease 
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• No effective antiviral treatment exists and most therapies focus on destruction of visible lesions, or induction of a cellular immune response 
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• A highly effective prophylactic HPV vaccine based on virus-like particles (VLP) has been licensed for the prevention of genital warts and associated vulvar, vaginal and cervical cancer.