In healthy subjects, circulating CD4+ and CD8+ T cells specific for HPV16 E antigens are frequently detected [13,14], while HPV-induced cervical intraepithelial neoplasia (CIN) or CC are characterized by weak HPV E antigen-specific T-cell immunity, and these merely CD4+ T cells have an impaired capacity to produce Th type 1 (Th1) and type 2 (Th2) cytokines [7,12,13,15-17]. The gene discussed is CD4; the disease is cervical squamous intraepithelial neoplasia.