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author:("Feng, xinghua")
Oncogenic human papillomavirus (HPV) viral load may inform the origin of newly detected infections and characterize oncogenic HPV natural history in mid-adult women. From 2007–2011, we enrolled 521 25–65 year old female online daters and followed them triannually with mailed health and sexual behavior questionnaires and kits for self-sampling for PCR-based HPV DNA testing. Samples from oncogenic HPV positive women were selected for type-specific DNA load testing by real-time PCR with adjustment for cellularity. Linear or logistic regression models were used to evaluate relationships between viral levels, health and sexual behavior, and longitudinal oncogenic HPV detection. Type-specific viral levels were borderline significantly higher in oncogenic HPV infections that were prevalent versus newly detected (p=0.092), but levels in newly detected infections were higher than in infections re-detected after intercurrent negativity (p<.001). Recent sex partners were not significantly associated with viral levels. Compared to prevalent infections detected intermittently, the likelihood of persistent (OR=4.31,95%CI:2.20–8.45) or single-time (OR=1.32,95%CI:1.03–1.71) detection increased per 1-unit increase in baseline log10 viral load. Viral load differences between re-detected and newly detected infections suggest a portion of new detections were due to new acquisition, although report of recent new sex partners (a potential marker of new infection) was not predictive of viral load; oncogenic HPV infections in mid-adult women with new partners likely represent a mix of new acquisition and reactivation or intermittent detection of previous infection. Intermittent detection was characterized by low viral levels, suggesting that intermittent detection of persisting oncogenic HPV infection may be of limited clinical significance
PMCID: PMC3947429  PMID: 24136492
human papillomavirus; viral load; persistence; women; epidemiology
2.  Rates and Determinants of Oral Human Papillomavirus (HPV) Infection in Young Men 
Sexually transmitted diseases  2012;39(11):860-867.
Little is known about rates and determinants of oral human papillomavirus (HPV) infection, an infection that is etiologically linked with oropharyngeal cancers.
A cohort of male university students (18–24 years of age) was examined every 4 months (212 men; 704 visits). Oral specimens were collected via gargle/rinse and swabbing of the oropharynx. Genotyping for HPV type 16 (HPV-16) and 36 other alpha-genus types was performed by PCR-based assay. Data on potential determinants was gathered via clinical examination, in-person questionnaire, and biweekly online diary. Hazard ratios (HR) were used to measure associations with incident infection.
Prevalence of oral HPV infection at enrollment was 7.5% and 12-month cumulative incidence was 12.3% (95% confidence interval (CI): 7.0, 21.3). Prevalence of oral HPV-16 was 2.8% and 12-month cumulative incidence was 0.8% (CI: 0.1, 5.7). 28.6% of prevalent and none of incident oral HPV infections were detected more than once. In a multivariate model, incident oral HPV infection was associated with recent frequency of performing oral sex (≥1 per week: HR=3.7; CI: 1.4, 9.8), recent anal sex with men (HR=42.9; CI: 8.8, 205.5), current infection with the same HPV type in the genitals (HR=6.2; CI: 2.4, 16.4) and hyponychium (HR=11.8, CI: 4.1; 34.2).
Although nearly 20% of sexually active male university students had evidence of oral HPV infection within 12 months, most infections were transient. HPV-16 was not common. Sexual contact and autoinoculation appeared to play independent roles in the transmission of alpha-genus HPV to the oral cavity of young men.
PMCID: PMC4375438  PMID: 23064535
HPV; oral HPV; young men; epidemiology
3.  Characterization of three novel human papillomavirus types isolated from oral rinse samples of healthy individuals 
Despite the strong evidence of HPV infection as the etiological agent in a subset of oral cancer, oral α-HPV detection is rare in healthy individuals, and little is known of the existing of novel HPV types in oral cavity.
We determined whether novel HPV types can be isolated from oral rinse samples collected from healthy individuals.
Study design
We performed rolling circle amplification (RCA) coupled with degenerated PCR assay on 48 oral rinse samples to amplify novel HPV types. Full length HPV DNA was cloned using long range PCR. Quantitative type specific Taqman assays were used to determine the prevalence of novel HPV types in 158 archived oral tissue samples.
We were able to isolate four novel human papillomavirus types. Full length HPV DNA was cloned for three of the four novel HPV types. All four HPV types belong to the genus Gammapapillomavirus (γ-PV), where HPV 171 is most closely related to HPV 169, showing 88% similarity; HPV 172 is most closely related to HPV 156, showing 70% similarity; HPV 173 is most closely related to HPV 4, showing 73% similarity; oral sample lavage (OSL) 37 is most closely related to HPV 144, showing 69% similarity. Finally, we showed that HPV 173 was rarely present in oral tissues (2/158), HPV 172 was only detected in normal oral tissues (25/76), and HPV 171 was more prevalent in malignant oral tissues (17/82 vs 10/76, p=0.21).
Novel γ-HPV types are present in oral cavity of healthy individuals.
PMCID: PMC3898882  PMID: 24268765
HPV; oral lavage; oral squamous cell carcinoma
Journal of medical virology  2009;81(4):713-721.
Human papillomavirus (HPV) RNA levels may be a more sensitive early indicator of predisposition to carcinogenesis than DNA levels. We evaluated whether levels of HPV-16 and HPV-18 DNA and messenger RNA (mRNA) in newly detected infections are associated with cervical lesion development. Female university students were recruited from 1990-2004. Cervical samples for HPV DNA, HPV mRNA, and Papanicolaou testing were collected tri-annually, and women were referred for colposcopically-directed biopsy when indicated. Quantitative real-time polymerase chain reaction of L1 and E7 DNA and E7 mRNA was performed on samples from women with HPV-16 and HPV-18 infections that were incidently detected by consensus PCR. Adjusting for other HPV types, increasing E7 cervical HPV-16 mRNA levels at the time of incident HPV-16 DNA detection were associated with an increased risk of cervical intraepithelial neoplasia grade 2 to 3 (HR per 1 log10 increase in mRNA=6.36,95%CI=2.00-20.23). Increasing HPV-16 mRNA levels were also associated with an increased risk of cervical squamous intraepithelial lesions; the risk was highest at the incident positive visit and decreased over time. Neither HPV-16 E7 DNA levels nor HPV-18 E7 DNA nor mRNA levels were significantly associated with cervical lesion development. Report of >1 new partner in the past 8 months (relative to no new partners) was associated with increased HPV mRNA (viral level ratio [VLR]=10.05,95%CI=1.09-92.56) and increased HPV DNA (VLR=16.80,95%CI=1.46-193.01). In newly detected HPV-16 infections, increasing levels of E7 mRNA appear to be associated with an increased risk of developing cervical pre-cancer.
PMCID: PMC3984467  PMID: 19235870
HPV; viral load; mRNA; cervical pre-cancer
5.  Prevalence and risk factors for oncogenic HPV infections in high-risk mid-adult women 
Sexually transmitted diseases  2012;39(11):848-856.
The epidemiology of high-risk (hr) HPV infections in mid-adult women with new sex partners is undefined.
We analyzed baseline data from 518 25–65 year old female online daters. Women were mailed questionnaires and kits for self-collecting vaginal specimens for PCR-based hrHPV testing. Risk factors for infection were identified using Poisson regression models to obtain prevalence ratios (PRs).
The prevalence of hrHPV infection was 35.9%. In multivariate analysis restricted to sexually active women, the likelihood of hrHPV infection was associated with abnormal Pap test history (PR=1.42, 95% CI:1.10–1.84), lifetime number of sex partners >14 (relative to 1–4; PR=2.13, 95% CI:1.13–4.02 for 15–24 partners and PR=1.91, 95% CI:1.00–3.64 for ≥25 partners), male partners with ≥1 concurrent partnership (PR=1.34, 95% CI:1.05–1.71) and male partners whom the subject met online (PR=1.39, 95% CI:1.08–1.79). Age was inversely associated with infection only in women who were sexually inactive (PR=0.67 per 5-year age difference, adjusted for Pap history and lifetime number of partners). Compared to sexually inactive women, the likelihood of infection increased with increasing risk level, (from low-risk to high-risk partners) (p<.0001 by trend test). In multivariate analysis, infection with multiple versus single hrHPV types was inversely associated with ever having been pregnant (PR=0.64, 95% CI:0.46–0.90) and recent consistent condom use (PR=0.56, 95% CI:0.32–0.97), and positively associated with genital wart history (PR=1.43, 95% CI:1.03–1.99).
Measures of both cumulative and recent sexual history were associated with prevalent hrHPV infection in this high-risk cohort of mid-adult women.
PMCID: PMC3476060  PMID: 23064533
HPV; human papilloma virus; mid-adult; prevalence; risk factors
6.  Circumcision and acquisition of HPV infection in young men 
Sexually transmitted diseases  2011;38(11):1074-1081.
The role of circumcision in male HPV acquisition is not clear.
Male university students (18–20 years of age) were recruited from 2003–2009 and followed tri-annually. Shaft/scrotum, glans, and urine samples were tested for 37 alpha HPV genotypes. Cox proportional hazards methods were used to evaluate the association between circumcision and HPV acquisition. Logistic regression was used to assess whether number of genital sites infected at incident HPV detection or site of incident detection varied by circumcision status.
In 477 men, rates of acquiring clinically-relevant HPV types (high-risk types plus types 6 and 11) did not differ significantly by circumcision status (hazard ratio [HR] for uncircumcised relative to circumcised subjects: 0.9[95%CI:0.7–1.2]). However, compared to circumcised men, uncircumcised men were 10.1 (95%CI:2.9–35.6) times more likely to have the same HPV type detected in all 3 genital specimens than in a single genital specimen and were 2.7 (95%CI:1.6–4.5) times more likely to have an HPV-positive urine or glans specimen at first detection.
While the likelihood of HPV acquisition did not differ by circumcision status, uncircumcised men were more likely than circumcised men to have infections detected at multiple genital sites, which may have implications for HPV transmission.
PMCID: PMC3210112  PMID: 21992987
HPV; human papilloma virus; circumcision; epidemiology; risk factors
7.  Serum Antibody Response Following Genital α9 Human Papillomavirus Infection in Young Men 
The Journal of Infectious Diseases  2011;204(2):209-216.
Background. Although the prevalence of human papillomavirus (HPV) genital infection is similarly high in males and females, seroprevalence is lower in males. This study assessed rates and determinants of seroconversion after detection of genital HPV infection in young men.
Methods. We investigated HPV type-specific seroconversion in a cohort of heterosexual male university students who had an α9 HPV type (HPV-16, -31, -33, -35, -52, -58, or -67) detected in the genital tract (n = 156). HPV DNA and antibodies were detected and typed using liquid bead-based multiplex assays. We calculated seroconversion using Kaplan–Meier survival analysis. Cox proportional hazards models with generalized estimating equations were used to examine associations with seroconversion.
Results. Within 24 months of detecting genital HPV infection, type-specific seroconversion ranged from 4% for HPV–52 to 36% for HPV-31. HPV-16 seroconversion at 24 months was 13% (95% confidence interval [CI], 7%–25%). Among incident HPV infections, ever cigarette smoking and infection site(s) (shaft/scrotum and glans/urine vs shaft/scrotum or glans/urine only) were positively associated with type-specific seroconversion.
Conclusions. For each of the α9 HPV types, type-specific seroconversion within 24 months was observed in 36% or less of infected men. Seroconversion might be related to cigarette smoking and genital site(s) infected.
PMCID: PMC3114468  PMID: 21673030
Characterizing short-term detection patterns of young women’s incident alpha-genus human papillomavirus (HPV) infections may further understanding of HPV transmission.
Between 2000–2007, we followed 18–22 year old female university students with triannual HPV DNA and Papanicolau testing. Using Kaplan-Meier methods, we estimated: duration of detectable, type-specific incident infections; time to re-detection (among infections that became undetectable); and time to cervical lesion development after incident infection. We evaluated risk factors for short-term persistent versus transient infection with logistic regression.
303 incident type-specific infections were detected in 85 sexually active women. Median time to first negative test after incident infection was 9.4 (95%CI:7.8–11.2) months; 90.6% of infections became undetectable within two years. 19.4% of infections that became undetectable were re-detected within one year. Cervical lesions were common, and 60% were positive for multiple HPV types in concurrent cervical swabs. Incident HPV detection in the cervix only (versus the vulva/vagina only or both sites) was associated with short-term transience.
While most incident infections became undetectable within two years, re-detection was not uncommon. Cervical lesions were a common early manifestation of HPV infection.
It remains unclear whether potentially modifiable risk factors can be identified to reduce infection duration (and transmission likelihood).
PMCID: PMC3078690  PMID: 21173170
human papillomavirus; incidence; duration; persistence; women; epidemiology
Little is known about detection of genital human papillomavirus (HPV) types in women’s fingertips. The study objectives were to determine the presence of genital HPV types in fingertip samples and agreement between fingertip and genital samples for detecting HPV.
At tri-annual visits, genital and fingertip samples were collected from female university students and tested for 37 HPV genotypes by PCR-based assay. Type-specific concordance between paired fingertip and genital samples was evaluated using a kappa statistic for percent positive agreement (“kappa +”). Paired samples with type-specific concordant fingertip and genital results were selected for variant characterization.
A total of 357 fingertip samples were collected from 128 women. HPV prevalence in fingertip samples was 14.3%. Although percent positive agreement between fingertips and genitals for detecting type-specific HPV was low (17.8%; kappa+=0.17, 95%CI:0.10–0.25), 60.4% of type-specific HPV detected in the fingertips was detected in a concurrent genital sample. All but one of 28 paired concordant samples were positive for the same type-specific variant in the fingertip and genital sample. Re-detection of HPV types at the subsequent visit was more common in genital samples (73.3%) than in fingertip samples (14.5%) (p<.001).
Detection of genital HPV types in the fingertips was not uncommon. While impossible to distinguish between deposition of DNA from the genitals to the fingertips and true fingertip infection, the rarity of repeat detection in the fingertips suggests that deposition is more common.
Finger-genital transmission is plausible, but unlikely to be a significant source of genital HPV infection.
PMCID: PMC2901391  PMID: 20570905
human papillomavirus; fingertip; genital; women; epidemiology
10.  Evaluation of Transported Dry and Wet Cervical Exfoliated Samples for Detection of Human Papillomavirus Infection▿  
Journal of Clinical Microbiology  2010;48(9):3068-3072.
We determined the feasibility of human papillomavirus (HPV) detection in cervical exfoliated cells collected as dry swab samples. Both dry cervical swab and specimen transport medium (STM) cervical swab samples were collected from 135 patients attending either colposcopy or women's clinics in Guayaquil, Ecuador, who had a cytology diagnosis within 6 months. HPV was detected by dot blot hybridization and genotyped by the liquid bead microarray assay (LBMA). Overall, 23.1% of dry samples were positive for any high-risk HPV types, and 24.6% of STM samples were positive for any high-risk HPV types. Of 125 paired samples, the type-specific high-risk HPV proportion positive agreement was 60.7% (kappa, 0.69; 95% confidence interval [CI], 0.53 to 0.82). Of six women with cytological evidence of invasive cervical cancer, high-risk HPV DNA was detected in three of their STM samples and in five of their dry samples. Dry samples were more likely to be insufficient for HPV testing than STM samples. Consistent with this observation, the amount of genomic DNA quantitated with the β-actin gene was almost 20 times lower in dry samples than in STM samples when detected by the real-time TaqMan assay; however, HPV DNA viral loads in dry samples were only 1.6 times lower than those in matched STM samples. We concluded that exfoliated cervical cells could be collected as dry swab samples for HPV detection.
PMCID: PMC2937663  PMID: 20610686
11.  Risk of Female Human Papillomavirus Acquisition Associated with First Male Sex Partner 
The Journal of infectious diseases  2008;197(2):279-282.
To quantify the risk of human papillomavirus (HPV) acquisition associated with a first male sex partner and to identify associated risk factors, we analyzed data from women who were enrolled before or within 3 months of first intercourse with a male partner and were censored at the report of a second partner. The 1-year cumulative incidence of first HPV infection was 28.5% (95% confidence interval, 20.6%–38.6%) and increased to almost 50% by 3 years. The risk was increased when the first male partner was sexually experienced. Our results indicate a high risk of HPV infection in young women who have had just 1 male sex partner.
PMCID: PMC2875685  PMID: 18179386
12.  Sequence Variation of Human Papillomavirus Type 16 and Measurement of Viral Integration by Quantitative PCR▿  
Journal of Clinical Microbiology  2008;47(3):521-526.
Given that the integration of human papillomavirus type 16 (HPV16) into the host genome occurs preferentially with the disruption of the E2 gene, a ratio of E2 to E7 gene copies is often used as a marker for integration. It is largely undetermined, however, whether ratio estimates are affected by HPV intratypic variations. We assembled four plasmid constructs, each containing a DNA fragment from an HPV16 European, Asian-American, African-1, or African-2 variant. These constructs and nine cervical swab samples were assayed by real-time PCR with two primer-probe sets for each gene: a specific set, fully complementary to the HPV16 prototype, and a degenerate set, incorporating degenerate bases at positions where nucleotides differed among the variants. The ratio of E2 to E7 gene copies for the European variant construct was close to 1, no matter which sets of primers and probes were used. While the ratios for the African-1 and Asian-American variant constructs remained close to 1 with the degenerate sets of primers and probes, the ratios were 0.36 and 2.57, respectively, with the specific sets of primers and probes. In addition, a nucleotide alteration at the position immediately following the 3′ end of the E2 forward primer binding site was found to be responsible for an underestimation of E2 gene copies for the African-2 variant construct. Similar patterns were found in nine cervical samples. In conclusion, mismatches between the primers and probes and their targets due to HPV16 intratypic variations would introduce errors in testing for integration; this situation can be sufficiently ameliorated by incorporating degenerate bases into the primers and probes.
PMCID: PMC2650947  PMID: 19116350
13.  Development and Evaluation of a Liquid Bead Microarray Assay for Genotyping Genital Human Papillomaviruses▿ †  
Journal of Clinical Microbiology  2009;47(3):547-553.
We developed a liquid bead microarray (LBMA) assay for genotyping genital human papillomaviruses (HPVs) based on the MY09-MY11-HMB01 PCR system and the reverse line blot (RLB) assay probe sequences. Using individual HPV plasmids, we were able to detect as few as 50 copies per reaction. In two separate retrospective studies, the LBMA assay was compared to the RLB assay and to the Hybrid Capture II (hc2) assay. Testing was performed without knowledge of other assay results. In the first study, 614 cervical swab samples (enriched for HPV infection) from 160 young women were tested for HPV DNA, and 360 (74.8%) type-specific HPV infections were detected by both assays, 71 (14.8%) by the LBMA assay only, and 50 (10.4%) by the RLB assay only. Type-specific agreement for the two assays was excellent (99.1%; kappa = 0.85; 95% confidence interval [95% CI], 0.82 to 0.88). Samples with discrepant LBMA and RLB test results tended to have low viral loads by a quantitative type-specific PCR assay. In the second study, cervical swab samples from 452 women (including 54 women with histologically confirmed cervical-intraepithelial neoplasia grade 2 or worse [≥CIN2]) were tested initially by the hc2 and subsequently by the LBMA assay. The estimated sensitivities for ≥CIN2 were similar for the LBMA and hc2 assays (98.4% [95% CI, 95.0 to 100%] and 95.6% [95% CI, 89.2 to 100%], respectively). The percentages of negative results among 398 women without ≥CIN2 were similar for the LBMA and hc2 assays (45% and 50%, respectively). The repeat test reproducibility for 100 samples was 99.1% (kappa = 0.92; 95% CI, 0.90 to 0.95). We conclude that the new LBMA assay will be useful for clinical and epidemiological research.
PMCID: PMC2650937  PMID: 19144800

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