Introduction: Conservative treatment with intralesional interferon (IFN) is a therapeutic option for cervical intraepithelial neoplasia (CIN) patients of childbearing age. Materials and Methods: The study group was made up of patients diagnosed with a highgrade lesion and treated with intralesional human recombinant IFNα-2b. Vaginal secretion was collected during IFNα-2b treatment for analysis of cytokines and viral load. Results: The initial histology diagnostic was 62.5% (n = 5) with CIN 2 and 37.5% (n = 3) with CIN 3. In terms of clinical evaluation and anatomopathology, 6.5% (n = 5) had a good clinical response, while 37.5% (n = 3) had therapeutic failure. All the patients with therapeutic failure were smokers. Interleukin 6 and tumor necrosis factor-α concentrations were raised at the sixth application for the patient group who failed to respond to therapy compared to the responsive group (p = 0.0357). Patients with a good response exhibited a reduction in human papillomavirus viral load (p = 0.03). Conclusions: Patients that had a good response had lower concentrations of inflammatory cytokines than did non-responders.