Evidence from allograft recipients and HIV-infected individuals (Palefsky et al, 1999) also indicates that it is the absolute deficit in CD4+ T cells which is the important risk factor for HPV-induced disease and associated neoplastic progression in the immunocompromised individual, and CD4+ T cells have been shown to be prominent in resolving cutaneous (Iwatsuki et al, 1986) and genital warts (Coleman et al, 1994). This evidence concerns the gene CD4 and anogenital human papillomavirus infection.