Percentage of CD28–CD8+ T cells of control, HPV-I, and CIN-I groups. Controls without cervical lesions diagnosed by Papanicolaou, non-neoplastic lesions associated with Human papillomavirus infection (HPV-I) or Cervical intraepithelial neoplastic-I (CIN-I), both diagnosed by biopsy. By Analysis of variance (ANOVA) testing, we found a statistically significant difference between the percentage of CD28–CD8+ T cells in the CIN-I group compared to the HPV-I and control groups (p <0.01).