Incident cervical HPV infections in young women: Transition probabilities for CIN and infection clearance

"Background: We describe transition probabilities for incident human papillomavirus (HPV) 16/18/31/33/35/45/52/58/59 infections and cervical intraepithelial neoplasia (CIN) 1 lesions. Methods: Women ages 16 to 23 years underwent cytology and cervical swab PCR testing for HPV at approximately 6-month intervals for up to 4 years in the placebo arm of an HPV vaccine trial. The cumulative proportion of incident HPV infections with diagnosed CIN, clearing (infection undetectable), or persisting without CIN, were estimated. Results: Most incident infections cleared, without detection of CIN, ranging at 36 months from 66.9% for HPV31 to 91.1% for HPV59. There was little variation in the 36-month proportion of incident HPV16, 18, and 31 infections followed by a CIN1 lesion positive for the relevant HPV type (range 16.7%-18.6%), with lower risks for HPV59 (6.4%) and HPV33 (2.9%). Thirty-six-month transition probabilities for CIN2 ranged across types from 2.2% to 9.1%; however, the number of events was generally too small for statistically significant differences to be seen across types for this endpoint, or CIN3. Conclusions: Some incident HPV types appear more likely to result in diagnosed CIN1 than others. The relative predominance of HPV16, vis-à-vis some other high-risk HPV types (e.g., HPV33) in prevalent CIN2/3, appears more directly associated with relatively greater frequency of incident HPV16 infections within the population, than a higher risk of infection progression to CIN2/3. Impact: Nearly all incident HPV infections either manifest as detectable CIN or become undetectable within 36 months. Some HPV types (e.g., 16 and 33) appear to have similar risk of CIN2/3 despite widely varied incidence. ©2011 AACR.

Adenocarcinoma in situ and associated human papillomavirus type distribution observed in two clinical trials of a quadrivalent human papillomavirus vaccine

The primary objective of this report is to describe the detection of adenocarcinoma in situ (AIS) and associated human papillomavirus (HPV) type distribution that was observed in the context of two phase 3 clinical trials of a quadrivalent HPV6/11/16/18 vaccine. In this intention-to-treat analysis, we include all women who had at least one follow-up visit postenrollment. Healthy women (17,622) aged 15-26 with no history of HPV disease and a lifetime number of less than five sex partners (average follow-up of 3.6 years) were randomized (1:1) to receive vaccine or placebo at day 1, months 2, and 6. Women underwent colposcopy and biopsy according to a Papanicolaou triage algorithm. All tissue specimens were tested for 14 HPV types and were adjudicated by a pathology panel. During the trials, 22 women were diagnosed with AIS (six vaccine and 16 placebo). There were 25 AIS lesions in total, with HPV16/18 present in 96% (24 of 25 with 15 of 25 as single infections). Only two of 22 women had concomitant cytology results suggesting glandular abnormality. Colposcopic impressions (25 total) were either negative or indicated squamous lesions only. Of women with AIS, all six in the vaccine cohort and seven of 16 in the placebo cohort were infected at baseline with the same HPV type that was detected in the AIS lesion. Concurrent squamous lesions were detected in 20 of these 22 women. In summary, our findings show that AIS evades colposcopic and cervical cytologic detection. As most AIS lesions were HPV16/18-related, prophylactic HPV vaccination should reduce the incidence of invasive adenocarcinoma. Copyright © 2011 UICC

E7 oncoprotein of human papillomavirus type 16 expressed constitutively in the epidermis has no effect on E7-specific B- or Th-repertoires or on the immune response induced or sustained after immunization with E7 protein

A line of FVB (H-2(q)) mice transgenic for the E6/E7 open reading frames of Human Papillomavirus type 16 driven from the alpha-A crystallin promoter expresses E7 mRNA in lens and skin epithelium. E7 protein is detectable in adult skin, coinciding with the development or inflammatory skin disease, which progresses to papillomata and squamous carcinomata in some mice. By examining the outcome of parenteral immunization with E7 protein, we sought to determine whether endogenous expression of E7 in skin had induced a preexisting immune outcome, i.e., specific immunity or tolerance, or whether the mice remain naive (''ignorant'') to E7. Our data show that the antibody response to defined E7 B-epitopes, the proliferative response to Th epitopes, and the delayed-type hypersensitivity (DTH) response to whole E7 did not differ between groups or young and old E6/E7 transgenic mice (likely having different degrees of lifetime exposure to E7 protein) or between E6/E7-transgenic and nontransgenic parental strain control mice. Although an E7-specific CTL response could not be induced in the H-2(q) background of these mice, incorporation of a D-b allele into the genome allowed comparison of D-b-restricted CTL responses in E6/E7 transgenic and nontransgenic mice. Experiments indicated that the E7-immunization-induced CTL response did not differ significantly between E6/E7 transgenic and nontransgenic mice. We interpret these results to indicate that in spite of expression of E7 protein in adult skin, E6/E7 transgenic mice remain immunologically naive (ignorant) of E7 epitopes presented by immunization. (C) 1997 Academic Press