Analytic and clinical performance of cobas HPV testing in anal specimens from HIV-positive men who have sex with men.

Anal human papillomavirus (HPV) infections are common, and the incidence of anal cancer is high in HIV-infected men who have sex with men (MSM). To evaluate the performance of HPV assays in anal samples, we compared the cobas HPV test (cobas) to the Roche Linear Array HPV genotyping assay (LA) and cytology in HIV-infected MSM. Cytology and cobas and LA HPV testing were conducted for 342 subjects. We calculated agreement between the HPV assays and the clinical performance of HPV testing and HPV genotyping alone and in combination with anal cytology. We observed high agreement between cobas and LA, with cobas more likely than LA to show positive results for HPV16, HPV18, and other carcinogenic types. Specimens testing positive in cobas but not in LA were more likely to be positive for other markers of HPV-related disease compared to those testing negative in both assays, suggesting that at least some of these were true positives for HPV. cobas and LA showed high sensitivities but low specificities for the detection of anal intraepithelial neoplasia grade 2/3 (AIN2/3) in this population (100% sensitivity and 26% specificity for cobas versus 98.4% sensitivity and 28.9% specificity for LA). A combination of anal cytology and HPV genotyping provided the highest accuracy for detecting anal precancer. A higher HPV load was associated with a higher risk of AIN2/3 with HPV16 (P(trend) < 0.001), HPV18 (P(trend) = 0.07), and other carcinogenic types (P(trend) < 0.001). We demonstrate that cobas can be used for HPV detection in anal cytology specimens. Additional tests are necessary to identify men at the highest risk of anal cancer among those infected with high-risk HPV.

Risk factors for anal HPV infection and anal precancer in HIV-infected men who have sex with men.

BACKGROUND: Carcinogenic human papillomaviruses (HPVs) cause a large proportion of anal cancers. Human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) are at increased risk of HPV infection and anal cancer compared with HIV-negative men. We evaluated risk factors for HPV infection and anal precancer in a population of HIV-infected MSM. METHODS: Our study included 305 MSM at an HIV/AIDS clinic in the Kaiser Permanente Northern California Health Maintenance Organization. Logistic regression was used to estimate associations of risk factors comparing men without anal HPV infection; men with anal HPV infection, but no precancer; and men with anal precancer. RESULTS: Low CD4 count (<350 cells/mm(3)) and previous chlamydia infection were associated with an increased risk of carcinogenic HPV infection (odds ratio [OR], 3.65; 95% confidence interval [CI], 1.28-10.40 and OR, 4.24; 95% CI, 1.16-15.51, respectively). History of smoking (OR, 2.71 95% CI, 1.43-5.14), duration, recency, and dose of smoking increased the risk of anal precancer among carcinogenic HPV-positive men but had no association with HPV infection. CONCLUSIONS: We found distinct risk factors for anal HPV infection and anal precancer. Risk factors for HPV infection and anal precancer are similar to established risk factors for cervical cancer progression.

Human papillomavirus genotype attribution and estimation of preventable fraction of anal intraepithelial neoplasia cases among HIV-infected men who have sex with men.

BACKGROUND: The prevention of human papillomavirus (HPV)-induced anal cancer in high-risk populations such as human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) remains an urgent priority, given rising incidence rates despite widespread antiretroviral therapy use. METHODS: HPV genotypes and anal disease prevalence, by cytology and histopathologic findings, were evaluated among 363 HIV-infected MSM. We modeled fractions of high-grade anal intraepithelial neoplasia (HGAIN) attributable to individual carcinogenic HPV genotypes and estimated the range of the proportion of HGAIN cases potentially preventable by prophylactic HPV vaccines. RESULTS: HPV16 was the most common genotype overall (26.4% of cases) and among HGAIN cases (55%). Prevalence of multiple (≥ 2) carcinogenic HPV genotypes increased from 30.9% in cases of AIN grade <1 to 76.3% in cases of AIN grade 3 (P(trend) < .001). The fractions of HGAIN cases attributable to carcinogenic HPV16/18 targeted by currently licensed bivalent and quadrivalent HPV vaccines ranged from 12% to 61.5%, and the fractions attributable to carcinogenic HPV16/18/31/33/45/52/58 targeted by an investigational nonavalent HPV vaccine ranged from 39% to 89.4%. CONCLUSIONS: Our analytical framework allows estimation of HGAIN cases attributable to individual HPV genotypes in the context of multiple concurrent HPV infections, which are very common among HIV-infected MSM. Our results suggest that licensed and investigational HPV prophylactic vaccines have the potential to prevent a substantial proportion of HGAIN cases in this population.

A comparison of dacron versus Flocked nylon swabs for anal cytology specimen collection.

OBJECTIVES: We compared the performance of commonly used Dacron versus flocked nylon swabs for anal cytology. STUDY DESIGN: From 23 HIV-positive men screened at Kaiser Permanente San Francisco (San Francisco, Calif., USA), 2 anal specimens were collected, 1 with each swab in random order, and placed into liquid cytology medium. Specimens were tested for cellularity by quantifying a genomic DNA (erv-3). The number of cells was assessed from prepared slides by automated image analysis. Performance was compared between swabs using 2-sample t tests and standard crossover trial analysis methods accounting for period effect. RESULTS: Flocked swabs collected slightly more erv-3 cells than Dacron for the first sample although not significantly (p = 0.18) and a similar number of erv-3 cells for the second sample (p = 0.85). Flocked swabs collected slightly more cells per slide than the Dacron swabs at both time periods although this was only significant in the second time period (p = 0.42 and 0.03 for first and second periods, respectively). In crossover trial analysis, flocked swabs outperformed Dacron for cell count per slide based on slide imaging (p = 0.03), but Dacron and flocked swabs performed similarly based on erv-3 quantification (p = 0.14). CONCLUSIONS: Further studies should determine whether flocked swabs increase the representation of diagnostically important cells compared to Dacron.

Interrater agreement of anal cytology.

BACKGROUND: The majority of anal cancers are caused by persistent infections with carcinogenic human papillomaviruses (HPV). Similar to cervical carcinogenesis, the progression from HPV infection to anal cancer occurs through precancerous lesions that can be treated to prevent invasion. In analogy to cervical cytology, anal cytology has been proposed as a screening tool for anal cancer precursors in high-risk populations. METHODS: The authors analyzed the interobserver reproducibility of anal cytology in a population of 363 human immunodeficiency virus (HIV)-infected men who have sex with men (MSM). Liquid-based cytology (LBC) specimens were collected in the anal dysplasia clinic before the performance of high-resolution anoscopy on all patients. Papanicolaou-stained LBC slides were evaluated by 2 cytopathologists, each of whom was blinded to the clinical outcome and the other pathologist's results, using the revised Bethesda terminology. RESULTS: Overall agreement between the 2 observers was 66% (kappa, 0.54; linear-weighted kappa, 0.69). Using dichotomizing cytology results (atypical squamous cells of undetermined significance [ASC-US] or worse vs less than ASC-US), the agreement increased to 86% (kappa, 0.69). An increasing likelihood of testing positive for markers associated with HPV-related transformation, p16/Ki-67, and HPV oncogene messenger RNA was observed, with increasing severity of cytology results noted both for individual cytologists and for consensus cytology interpretation (P value for trend [p(trend)] < .0001 for all). CONCLUSIONS: Moderate to good agreement was observed between 2 cytopathologists evaluating anal cytology samples collected from HIV-positive MSM. A higher severity of anal cytology was associated with biomarkers of anal precancerous lesions. Anal cytology may be used for anal cancer screening in high-risk populations, and biomarkers of HPV-related transformation can serve as quality control for anal cytology.

A comparison of human papillomavirus genotype-specific DNA and E6/E7 mRNA detection to identify anal precancer among HIV-infected men who have sex with men.

BACKGROUND: Human papillomavirus (HPV) RNA detection is reportedly more specific for the detection of anogenital precancer than HPV DNA but it is unknown whether this is due to detection of RNA or due to HPV genotype restriction. METHODS: A total of 363 human immunodeficiency virus (HIV)-positive men who have sex with men had two anal cytology samples taken and were evaluated using high-resolution anoscopy and biopsies of visible lesions. Anal specimens were tested for E6/E7 RNA for five carcinogenic HPV genotypes (HPV16, 18, 31, 33, and 45) and tested for the DNA of 13 carcinogenic HPV genotypes. RESULTS: DNA testing was more likely to be positive than RNA testing (53% vs. 48%; P = 0.02) for the same five HPV genotypes in aggregate. When restricted to five HPV genotypes targeted by the RNA test, the sensitivity to detect anal precancer was the same for DNA and RNA (81%), whereas RNA was more specific than DNA (65% vs. 58%; P = 0.007). In comparison, DNA detection of all 13 carcinogenic HPV genotypes was more sensitive (96% vs. 81%; P = 0.001) but much less specific (65% vs. 33%; P < 0.001) as compared with RNA detection of the five HPV genotypes. CONCLUSION: After controlling for HPV genotypes, RNA was only slightly more specific than DNA detection for anal precancer. IMPACT: DNA or RNA testing for a subset of the most carcinogenic HPV genotypes may be useful for distinguishing between those HPV-positive men at higher and lower risk of anal precancer and cancer.

Human papillomavirus genotyping, human papillomavirus mRNA expression, and p16/Ki-67 cytology to detect anal cancer precursors in HIV-infected MSM.

OBJECTIVE: Anal cancer incidence is high in HIV-infected MSM. Screening for anal intraepithelial lesions and cancers is performed at specialized clinics and relies on high-resolution anoscopy (HRA) and anal cytology. Both approaches have limited reproducibility and sensitivity for detecting anal cancer precursors. We evaluated biomarkers for human papillomavirus (HPV)-related disease in a population of HIV-infected MSM. METHODS: A cross-sectional screening study with passive follow-up included 363 MSM followed at a HIV/AIDS clinic. All men had anal cytology samples taken and were evaluated using HRA and anal biopsies. Using a composite endpoint of biopsy results and cytology, we compared the performance of HPV16/18 genotyping, HPVE6/E7 mRNA expression, and p16/Ki-67 cytology to detect high-grade anal intraepithelial neoplasias (AINs). RESULTS: For all biomarkers analyzed, there was a significant trend of increasing percentage of men testing positive with increasing severity of disease (P < 0.001). HPV DNA testing had the highest sensitivity for anal intraepithelial neoplasia grade 2 and anal intraepithelial neoplasia grade 3 (AIN3), followed by p16/Ki-67, HPVE6/E7 mRNA testing, and HPV16/18 genotyping. The highest Youden's index was observed for HPVE6/E7 mRNA testing, followed by HPV16/18 genotyping, p16/Ki-67 cytology, and HPV DNA testing. Increasing the threshold for positivity of p16/Ki-67 to five or more positive cells led to significantly higher specificity, but unchanged sensitivity for detecting AIN3. CONCLUSION: Molecular features of anal disease categories are similar to those of corresponding cervical lesions. Biomarkers evaluated for cervical cancer screening may be used for primary anal cancer screening or to decide who should require immediate treatment vs. expectant management.