Retrospective Investigation of Human Papillomavirus Cervical Infection and Lymphoma Incidence: A Clinical and Pathological Evaluation

Objective: Human papillomavirus (HPV) persistence is considered the main risk factor for neoplastic progression, and evidence suggests that regulatory T cells play an important role in the failure of viral elimination. Regulatory T cells may be involved in maintaining a microenvironment favourable for viral persistence and neoplasticity, through a deregulation of the local immune response. The association between altered immune function and the development of chronic infections, cancer (solid and haematological), and autoimmune diseases is documented in the literature. The purpose of this retrospective analysis was to evaluate the possible correlation between HPV cervical infection and lymphoma incidence in women attending colposcopy due to an abnormal Pap smear during a period of 15 years. Design: This is a cross-sectional study. Participants: We investigated retrospectively the incidence of haematological diseases in women aged 21-84 with an abnormal Pap smear who referred to our centre between 2004 and 2019. Setting: This study was conducted at the university hospital. Methods: In our analysis, we included women with diagnoses of HL and NHL after the detection of abnormal Pap smears and HPV infections. We excluded patients with a diagnosis of lymphoma preceding the date of the abnormal Pap smear and HPV test. Results: We divided the patients into two groups in order to analyse the standard incidence ratio (SIR): HL patients (19/7,064, 0.26%) and NHL patients (22/7,064, 0.31%). In our sample, we reported a significant risk of developing lymphoma compared to the general population, both for HL and NHL disease, at age <45 years. Regarding HL, the SIR of disease in women <45 years was 4.886 (95% CI 2.775-9.6029) and in women between 45 and 59 years was 2.612 (95% CI 0.96-7.108804). On the other hand, for NHL in women <45 years, we reported an SIR of about 3.007 (95%, CI 1.273-7.101575), in women aged 45-59 years, the SIR was 4.291 (95% CI 2.444-7.534399), and in women aged 60-74 years, the SIR was 3.283 (95% CI 1.054-10.22303). Limitations: This retrospective analysis was conducted in a single centre in Northern Italy and did not consider all interregional differences existing in the country in terms of HPV genotypes, ethnicity, and population characteristics. Regarding the analysis of SIR for HL and NHL, we did not divide the disease into subtypes because of the small sample of cases. Finally, we considered in our analysis only women with an abnormal Pap smear and not the general population. Conclusions: Women with chronic and persistent HPV infections may have a higher relative risk of developing lymphoma. This possible association may be caused by the deregulation of the immune system response against HPV and the failure of viral clearance, especially in younger women.