A prospective cohort study to evaluate immunosuppressive cytokines as predictors of viral persistence and progression to pre-malignant lesion in the cervix in women infected with HR-HPV: study protocol

BACKGROUND: Cervical cancer (CC) is caused by a persistent infection of high-risk human papillomavirus (HR-HPV). While most HPV infections are transient, persistent HPV infections are a significant health problem in Mexico. With an estimated HPV prevalence of 10% among women in reproductive age, approximately 25% of these women present at least a positive result in triage test, which according to previous studies is expected to be confirmed as positive CIN-2/3. The immune system has a key role in the natural history of HPV infection; alterations in the cellular immune response are responsible for the failure to eliminate HPV. The objective of this project is to assess the prognostic value of detecting immune markers (IL-10, IL-4, TGFβ1, IFNγ, IL-6, and TNFα), the expression of HPV-HR E6/E7 proteins, and the viral load at the cervical level with respect to the persistence or clearance of HR-HPV infection, and the regression or progression of a cervical premalignant lesion. METHODS: A dynamic cohort study is being conducted in women with colposcopic, cytological, and histopathological results negative for squamous intraepithelial lesion (SIL) in the cervix and a positive HPV test; the subjects will be followed-up for 5 years, period from which 3 years have already elapsed, with yearly studies (colposcopy, cytology, and histopathology diagnosis, along with molecular HPV test, quantification of viral load and of IL-10, IL-4, TGFβ1, INFγ, IL-6, and TNFα levels, along with the expression of the HR-HPV E6/E7 proteins in the cervix as a viral marker. The outcome will be categorized as viral persistence or clearance; and as SIL persistence, progression, or regression. Binomial and/or multinomial regression models adjusted for potential confounders will be used, associating the relative risk of the outcome with the immune and viral markers evaluated. DISCUSSION: This research will generate knowledge about immune markers with predictive value for the persistence and clearance of HPV, which will improve the triage of positive HPV women and thus reduce the economic burden for the Mexican health system imposed by the management of high-grade SIL and CC cases, which are still detected in late stages.