Factors modifying the natural history of cervical intraepithelial neoplasia

In recent years, various factors have been reported to affect the natural history of cervical intraepithelial neoplasia (GIN). In view of the threat of the HIV pandemic, a primary role has been increasingly attributed to the immunosuppression resulting from human immunodeficiency virus (HIV) infection. The relationship of an infection to other sexually transmitted diseases (STDs)is complex; the natural history of CIN, whether treated surgically or managed conservatively, appears to be related to the degree of HIV-induced immunosuppression rather than to the acquisition of an infection per se. Different STDs have also been implicated in the development of CIN. Importantly, STDs involving the uterine cervix may act by impairing local cervical immunity leading, in turn, to reinfection and or superinfection with other agents, particularly differing HIV and human papillomavirus (HPV) subtypes. HPV infection is recognized as a major factor influencing the development, progression, and relapse of CIN. Specifically, HPV type 16 and 18 should be regarded as high-risk HPV types.