Epidemiologic correlates of antibody response to human papillomavirus among women at low risk of cervical cancer.

A population at low risk for developing cervical cancer in Southern Brazil was studied to identify the main determinants of serological response to human papillomavirus (HPV). Enzyme-linked immunosorbent assay tests were performed in 976 women to detect serum IgG antibodies against HPV 16 L1 virus-like particles (VLPs) and HPVs 16, 18, 6 and 11 L1 VLPs as a mixture of antigens. Women with four or more sexual partners were more likely to be seropositive than women with one partner (HPV 16 serology odds ratio [OR]=3.06, 95% confidence interval [CI]: 2.0-4.8; HPV 6/11/16/18 serology OR=4.64, 95% CI: 3.0-7.2). HPV DNA and both serological responses were associated. Those positives to HPV 16 serology were twice as likely to have a cytological diagnosis of squamous intraepithelial lesions (SILs) than seronegatives (OR=2.07; 95% CI: 1.0-4.5, and OR=1.73; 95% CI: 0.8-3.8). Seropositivity to HPV 16 and HPV 6/11/16/18 antigens seem to be better markers of past sexual activity than current HPV infection, and humoral response to HPV 16 or HPV 6/11/16/18 may not be a strong indicator of cervical lesions in populations at low risk for cervical lesions.

Prevalence and epidemiologic correlates of atypical squamous cells of undetermined significance in women at low risk for cervical cancer.

Our aim was to determine the prevalence and epidemiologic correlates of atypical squamous cells of undetermined significance (ASCUS) in a population at low risk for cervical cancer in Porto Alegre, Brazil. Sociodemographic data and gynecological and obstetrical history from 977 women screened at an outpatient clinic were recorded. Specimens were collected for Papanicolaou cervical cytology, colposcopy, and biopsy (if indicated). Sixty-two (6.3%) patients presented ASCUS, 21 (2.1%) presented low-grade squamous intraepithelial lesions, and 6 (0.6%) presented high-grade lesions. Presence of human papillomavirus (HPV) DNA in cervical cells (odds ratio (OR) = 1.57; confidence interval (CI) 95% = 1.11-2.23), history of HPV infection (OR = 3.12; CI 95% = 1.22-7.96), and becoming sexually active at 18 yr or younger (OR = 1.70; CI 95% = 1.15-2.51) were independently associated with ASCUS. ASCUS patients reported HPV infections and presented HPV DNA in cervical cells more often than did patients with normal cytology; therefore, they should be carefully monitored to ensure early detection of cancer precursor lesions and prevention of cervical cancer.

Comparison between hybrid capture II and polymerase chain reaction results among women at low risk for cervical cancer.

PURPOSE: Hybrid Capture (HC) is a new and powerful tool to detect DNA/RNA of several infectious agents. Regarding HPV DNA detection HC II has shown no false positive results due to contamination and its inter-laboratory reproducibility reaches 98%. It is also simpler and costs less than other methods such as Polymerase Chain Reaction (PCR) and it has shown a high correlation to clinical findings. Our objective is to compare HC II and PCR results among women at low risk for cervical cancer.METHODS: This is a cross-sectional study which enrolled 977 asymptomatic women aged 15 and 70 years. Squamous columnar junction samples were obtained and analyzed for HPV DNA either by HC II and PCR. Epidemiological factors and cyto-pathologic results were related to HPV DNA status. The Pearson Chi-square test and multiple logistic regression were performed to relate epidemiological and cytopathological variables and HPV DNA status.RESULTS: About 15.4% and 15.9% of women were HPV DNA positive by HC II and PCR respectively. Both were highly associated with cytology (P < 0.0001). The correlation to histopathology was also good with a higher significance for HC II. Factors related to HPV DNA detection by PCR were: oral contraceptive use (OR = 1.26; 95% CI = 1.2-1.62); history of genital HPV infection (2.11; 1.13-4.59); 3 or more sexual partners (1.35; 1.10-1.83); education (

Seroreactivity to human papillomavirus type 16 virus-like particles is lower in high-risk men than in high-risk women.

Seroreactivity to human papillomavirus type 16 (HPV-16) virus-like particles (VLPs) in men attending clinics for sexually transmitted diseases (STDs) in Denmark (n = 219) and Greenland (n = 88) was compared with seroreactivity in women attending the same clinics and was furthermore related to epidemiologic variables and concurrent HPV DNA detection. Risk factors for male seropositivity in Denmark were lifetime number of sex partners, a history of STDs, and sexual preference and in Greenland were ever having had syphilis and years at school. Although men reported significantly more sex partners, the mean seroreactivity was significantly lower in men than in women: 0.50 and 0.75, respectively, in Denmark and 0.53 and 0.86 in Greenland (P = .0001). Male seropositivity was not correlated with concurrent HPV DNA detection, but only 15 Danish and 6 Greenlandic men had HPV-16 DNA. Presence of HPV-16 VLP antibodies appears to be a biomarker for exposure to genital HPVs in men but is less sensitive than in women.

Seroreactivity to HPV16 virus-like particles as a marker for cervical cancer risk in high-risk populations.

Sexually transmitted genital human papillomavirus (HPV) infection, most often HPV 16, is considered the major etiologic determinant of cervical cancer. However, some studies have found relatively low prevalences of genital tract HPV DNA in some geographical areas, such as Greenland, that have high rates of cervical cancer. We sought to evaluate HPV 16 infection in high-risk cohorts using a serologic assay that assesses prior exposure as well as current infection and to compare the results with those obtained using a sensitive PCR-based HPV DNA assay. An ELISA based on HPV 16 virus-like particles was used to detect IgG serum antibodies in women attending sexually transmitted disease (STD) clinics in Nuuk, Greenland and Copenhagen, Denmark. Using a preassigned cut-off, 56% of Greenlandic and 41% of Danish women were seropositive (p = 0.02). In Greenlandic women, there was a non-significant increase in seropositivity with age, and odds ratios for seropositivity were similar for women with more than 5 lifetime sex partners. Seropositivity in the Danish women, however, increased linearly with increases in these 2 factors, which are likely correlates of lifetime exposure to genital HPVs. In contrast, any genital HPV DNA (HPV16 specifically) was detected in 24% and 36% of Greenlandic and Danish women, respectively and was most frequently detected in women below 20. The finding that HPV DNA prevalences, unlike seroprevalences, tended to decrease with increased lifetime risk of infection, provides an explanation for the lack of correlation between HPV DNA prevalences and cervical cancer risk in previous studies of high-risk populations.

Epidemiologic determinants of seroreactivity to human papillomavirus (HPV) type 16 virus-like particles in cervical HPV-16 DNA-positive and-negative women.

The epidemiologic determinants of seroreactivity to human papillomavirus (HPV) type 16 L1/L2 virus-like particles (VLPs) were assessed separately in HPV-16 DNA-positive and -negative women participating in a nested case-control study of incident cervical neoplasia. Seventy-four women with cervical HPV-16 DNA and 656 cytologically normal HPV-16 DNA-negative subjects were interviewed and tested at two time points for viral DNA and once (at the later time) for VLP seroreactivity. Among subjects who were currently HPV-16 DNA-negative, seroreactivity odds ratios increased from 2.9 for 2-5 male sex partners (vs. 0 or 1) to 5.4 for 6-9 partners and 14.0 for > or = 10. Thus, prior cervical infection may be a major determinant of seroreactivity in HPV-16 DNA-negative women. This trend was not observed in HPV-16 DNA-positive subjects. Seroreactivity was independently associated with oral contraceptive use, particularly in HPV-16 DNA-negative subjects with use for > or = 10 years. Consequently, a possible role for virus-steroid hormone interactions in seroconversion is suggested.

Evaluation of seroreactivity to human papillomavirus type 16 virus-like particles in an incident case-control study of cervical neoplasia.

An ELISA to detect serum IgG antibody response to human papillomavirus (HPV) type 16 virus-like particles (VLPs) was evaluated in a case-control study of cervical neoplasia, nested within a prospective cohort study. Subjects included 688 controls with continued normal cytology and 152 cases with confirmed incident squamous intraepithelial lesions who were tested for DNA for a broad spectrum of HPV types at cohort and follow-up of controls, 16.6% were seropositive compared with 30.8% and 52.4% of cases with low- and high-grade lesions, respectively. Of HPV-16 DNA-negative subjects, 16.5% were seropositive. Seropositivity increased from 22.2% in subjects who were HPV-16 DNA-positive by polymerase chain reaction once only (enrollment or follow-up) to 83.3% in those who were HPV-16 DNA-positive at both time points. These data imply that serum antibody to HPV-16 VLPs is a relatively sensitive indicator of persisting cervical HPV-16 infection.

Serologic response to human papillomavirus type 16 (HPV-16) virus-like particles in HPV-16 DNA-positive invasive cervical cancer and cervical intraepithelial neoplasia grade III patients and controls from Colombia and Spain.

A human papillomavirus (HPV) type 16 virus-like particle-based ELISA was used to assess antivirion immune responses in 300 women participating in cervical cancer case-control studies in Colombia and Spain. Virion IgG antibodies were detected in the sera of 51% and 59% of women with HPV-16 DNA-positive invasive cervical cancer and 81% and 73% of women with HPV-16 DNA-positive cervical intraepithelial neoplasia grade III (CIN III) in Colombia and Spain, respectively. Capsid antibodies were detected in 22% and 3% of cancer controls (P < .001) and in 43% and 10% of CIN III controls (P = .010) from Colombia and Spain, respectively. Since Colombia has an 8-fold higher incidence of cervical cancer, these results demonstrate an association between ELISA positivity and cancer risk. Capsid antibody responses did not correlate with humoral responses of the same women to HPV-16 E6 and E7 oncoproteins.

Immunization with viruslike particles from cottontail rabbit papillomavirus (CRPV) can protect against experimental CRPV infection.

We tested the ability of vaccination with virus-like particles (VLPs) to protect domestic rabbits against papillomas induced by the cottontail rabbit papillomavirus (CRPV). A recombinant baculovirus system that expressed only the L1 major papillomavirus structural protein or L1 plus the minor L2 protein was used in insect cells as the source of VLPs. Groups of 10 rabbits were immunized with native or denatured VLPs from CRPV or type 1 bovine papillomavirus by using Freund's adjuvant. Alum was used as the adjuvant for an additional group immunized with CRPV L1-L2 VLPs. Animals were challenged with 5 x 10(10) and 2 x 10(11) particles on opposing flanks. No protection was seen in rabbits immunized with native or denatured bovine papillomavirus L1-L2 or with denatured CRPV L1-L2. In these groups, the lower and higher challenge doses resulted in 27 of 30 animals with extensive papillomas, with each of the remaining animals having a smaller number of persistent papillomas. Progression to carcinoma developed in 20 rabbits. Animals inoculated with native CRPV VLPs composed of L1 alone or L1-L2 developed many fewer lesions; the lower and higher challenge doses resulted in 17 of 29 and 5 of 29 rabbits, respectively, with no lesions, and the remainder developed only one to eight papillomas, which all regressed except for those on 1 rabbit. None developed cancer within 1 year of infection. Rabbits vaccinated with native CRPV VLPs developed high-titer antibodies in an enzyme-linked immunosorbent assay based on native VLPs, and passive transfer of serum or immunoglobulin G from rabbits immunized with CRPV VLPs protected against CRPV challenge. We conclude that native VLPs can induce antibody-mediated, type-specific protection against experimental papillomavirus infection.