Papanicolaou smears and cervical inflammatory cytokine responses

Jo-Ann S Passmore, Chelsea Morroni, Samual Shapiro, Anna-Lise Williamson, Margaret Hoffman

In a case-control study among 2064 South African women to investigate the risk of clinically invasive cancer of the cervix, we found a marked reduction in the risk of cervical cancer among women who gave a history of ever having undergone even a single Pap smear, and a statistically significant decline in the HPV positivity rate correlated with the lifetime number of Pap smears received. HPV infections and their associated low-grade lesions commonly regress, indicating that most often there is an effective host immune response against HPV infection. We hypothesized that act of performing a Pap smear is associated with inflammatory responses at the site of trauma, the cervix, and that this inflammatory signalling may be an immunological factor initiating these productive anti-HPV responses. In the present study, a randomized controlled trial, we enrolled 80 healthy young women to investigate the impact of performing a Pap smear on cervical inflammation. Forty one women, in the intervention group, received a Pap smear at enrollment and cervicovaginal lavages (CVLs) were collected at baseline and 2 weeks later. Thirty nine women received no intervention at enrollment (control group) but CVLs were collected at enrolment and 2 weeks later. We assessed various markers of inflammation including IL-12 p70, TNF-alpha, IL-8, IL-6, IL-10, and IL-1beta in CVL specimens. While CVL levels of IL-8, IL-1beta and IL-6 remained unchanged following a Pap smear, markers of cell mediated immunity (IL-12 p70 and TNF-alpha) and T cell regulation (IL-10) were significantly elevated.