Anal human papillomavirus testing with Digene's hybrid capture 2 using two different sampling methods

Anal human papillomavirus infection: prevalence, diagnosis and treatment of related lesions

Human papillomavirus (HPV) infection is mostly asymptomatic, but may also have many diverse clinical signs encompassing benign ano-genital lesions, and carcinomas. Recently, interest has also particularly focused on anal cancer since, over the last decades, its incidence has been greatly increasing in developed countries, both in women and men and is drastically higher in specific risk groups, such as men who have sex with men (MSM) and HIV-1 infected individuals. Approximately 88% of anal cancer cases worldwide are associated with HPV infection. This review summarizes our current understanding of anal HPV infection, discussing its epidemiology and risk factors in various populations, and the state of the art in the detection of anal HPV infection and its related lesions through both cytology and histology. Finally, we discuss the clinical management and therapy for these lesions.

Use of human papillomavirus DNA, E6/E7 mRNA, and p16 immunocytochemistry to detect and predict anal high-grade squamous intraepithelial lesions in HIV-positive and HIV-negative men who have sex with men

Background

Men who have sex with men (MSM) are at high risk of having anal cancer. Anal high-grade squamous intraepithelial lesion (HSIL) is the precursor of anal cancer. We explored the use of different biomarkers associated with human papillomavirus (HPV) infection and HPV-mediated cell transformation to detect and predict HSIL among HIV-positive and HIV-negative MSM.

Methodology/Principal Findings

A total of 123 HIV-positive and 123 HIV-negative MSM were enrolled and followed for 12 months. High-resolution anoscopy (HRA) with biopsies were performed at every visit along with anal sample collection for cytology, high-risk HPV DNA genotyping, HPV E6/E7 mRNA, and p16 immunocytochemistry. Performance characteristics and area under the receiver operator characteristics curve were calculated for these biomarkers at baseline, and Cox regression compared the usefulness of these biomarkers in predicting incident HSIL. High-risk HPV DNA, E6/E7 mRNA, and p16 immunocytochemistry each identified 43–46% of MSM whose baseline test positivity would trigger HRA referral. E6/E7 mRNA had the highest sensitivity (64.7%) and correctly classified the highest number of prevalent HSIL cases. With the exception of p16 immunochemistry, most tests showed significant increases in sensitivity but decreases specificity versus anal cytology, while the overall number of correctly classified cases was not significantly different. Baseline or persistent type 16 and/or 18 HPV DNA was the only test significantly predicting incident histologic HSIL within 12 months in models adjusted for HIV status and low-grade squamous intraepithelial lesions at baseline.

Conclusions/Significance

Countries with a high HIV prevalence among MSM and limited HRA resources may consider using biomarkers to identify individuals at high risk of HSIL. E6/E7 mRNA had the highest sensitivity for prevalent HSIL detection regardless of HIV status, whereas type 16 and/or 18 HPV DNA performed best in predicting development of incident HSIL within 12 months.

Comparable performance of conventional and liquid-based cytology in diagnosing anal intraepithelial neoplasia in HIV-infected and -uninfected Thai men who have sex with men

BACKGROUND

Anal cytology has increasingly been used to screen for anal intraepithelial neoplasia (AIN) among men who have sex with men (MSM) at increased risk for anal cancer. Use of liquid-based cytology has been reported to reduce fecal and bacterial contamination and air-drying artifact compared with conventional cytology. Costs associated with liquid-based cytology, however, may limit its use in resource-limited settings.

METHODS

Anal swab samples were collected from MSM participants and used to prepare conventional and liquid-based cytology slides. Abnormal conventional cytology results triggered referral for high-resolution anoscopy and biopsy. Agreement between the 2 cytology techniques and the positive predictive value ratios of histology confirmed AIN were calculated.

RESULTS

Among 173 MSM, abnormal anal cytology was identified in 46.2% of conventional and 32.4% of liquid-based slides. The results agreed in 62.4% of cases with a κ value of 0.49 (P < 0.001). HIV-infected MSM had a 3.6-fold increased odds of having discordant anal cytology results (95% confidence interval: 1.6 to 7.8; P = 0.001) compared with HIV-uninfected MSM. Histological AIN 2 and 3 were identified in 20 MSM. The positive predictive value ratios and 95% confidence interval indicated no difference between the 2 techniques.

CONCLUSIONS

Conventional anal cytology may be a preferred option for resource-limited settings given comparable performances to liquid-based cytology for the detection of AIN, although the agreement between the 2 techniques was lower among HIV-infected MSM. Due to high prevalence of abnormal anal cytology and AIN, health systems should prepare adequate infrastructure for high-resolution anoscopy services and AIN treatment.

Screening for anal neoplasia: anal cytology - sampling, processing and reporting

Anorectal cytology (ARC) is increasingly accepted as a valid screening tool for the diagnosis of squamous intraepithelial lesions in populations at increased risk for anal cancer. As with cervical cancer screening protocols, proper patient preparation, specimen collection and specimen processing are essential for obtaining an optimal cytological sample. With attention and experience, the clinician can collect the best possible ARC specimen for laboratory evaluation. The incorporation of repeated interval anal cytology into standard surveillance practices for high-risk individuals is a valuable tool for the early detection of human papillomavirus-related anal squamous epithelial lesions and the prevention of anal squamous cell carcinomas.

Morphometric analysis of dendritic cells from anal mucosa of HIV-positive patients and the relation to intraepithelial lesions and cancer seen at a tertiary health institution in Brazil

PURPOSE: To morphometrically quantify CD1a+ dentritic cells and DC-SIGN+ dendritic cells in HIV-positive patients with anal squamous intraepithelial neoplasia and to evaluate the effects of HIV infection, antiretroviral therapy and HPV infection on epithelial and subepithelial dendritic cells. METHODS: A prospective study was performed to morphometrically analyze the relative volume of the dendritic cells and the relationship between anal intraepithelial neoplasia and cancer in HIV-positive patients from the Tropical Medicine Foundation of Amazonas, Brazil. All patients were submitted to biopsies of anorectal mucosa to perform a classic histopathological and immunohistochemical analysis, employing antibodies against CD1a and DC-SIGN for the morphometric quantification of dendritic cells. RESULTS: HIV-negative patients displayed a CD1a DC density significantly higher than that of HIV-positives patients (3.75 versus 2.54) (p=0.018), and in patients with severe anal intraepithelial neoplasia had correlated between DC CD1a density with levels of CD4 + cells (p: 0.04) as well as the viral load of HIV-1 (p: 0.035). A not significant rise in the median density of CD1a+ DC was observed in the HIV positive/ HAART positive subgroup compared to the HIV positive/ HAART negative subgroup. The CD1a+ DC were also significantly increased in HIV-negative patients with anorectal condyloma (2.33 to 3.53; p=0.05), with an opposite effect in HIV-positive patients. CONCLUSIONS: Our data support an enhancement of the synergistic action caused by HIV-HPV co-infection on the anal epithelium, weakening the DC for its major role in immune surveillance. Notoriously in patients with severe anal intraepithelial neoplasia, the density of CD1a+ epithelial dendritic cells was influenced by the viral load of HIV-1. Our study describes for the first time the density of subepithelial DC-SIGN+ dendritic cells in patients with anal severe anal intraepithelial neoplasia and points to the possibility that a specific therapy for HIV induces the recovery of the density of epithelial DC.

Detection of multiple human papillomavirus genotypes in anal carcinoma

Infection with human papillomavirus (HPV) is a major risk factor for development of anal squamous cell carcinoma. Despite over 100 genotypes of the virus, HPV 16 and 18 are considered pathogenic as they are seen in the majority of cervical and anal cancers. We have employed a custom microarray to examine DNA for several HPV genotypes. We aimed to determine the accuracy of our microarray in anal cancer DNA for HPV genotypes compared to the DNA sequencing gold standard.

METHODS

We utilized a sensitive microarray platform to classify 37 types of mucosal HPVs including 14 known high-risk and 23 low-risk types based on cervical cancer data. We utilized DNA from pathologically confirmed cases of anal squamous cell carcinoma. All samples underwent microarray HPV genotyping and PCR analysis.

RESULTS

HPV was detected in 18/20 (90%) anal cancers. HPV genotypes 16 and 18 were present in the majority of specimens, with HPV 16 being the most common. Eighty percent of anal cancers had at least two HPV types. Ten percent of cases (2/20) tested negative using our microarray; DNA sequencing confirmed the lack of presence of HPV DNA in these samples.

CONCLUSIONS

Microarray technology is an accurate way to screen for various genotypes of HPV in anal cancer, with 100% correlation with genomic DNA detection of HPV. The majority of anal cancers in our study associated with pathogenic HPV 16 and/or 18. Other HPV genotypes are present simultaneously with HPV 16 and 18, and might contribute to its pathogenesis.

[Utility of molecular biology techniques in the diagnosis of sexually transmitted diseases and genital infections]

Historically, the diagnosis of sexually transmitted diseases (STDs) has been difficult. The introduction of molecular biology techniques in microbiological diagnosis and their application to non-invasive samples has produced significant advances in the diagnosis of these diseases. Overall, detection of Neisseria gonorrhoeae by molecular biology techniques provides a presumptive diagnosis and requires confirmation by culture in areas with a low prevalence. For Chlamydia trachomatis infections, these techniques are considered to be the most sensitive and specific procedures for mass screening studies, as well as for the diagnosis of symptomatic patients. Diagnosis of Mycoplasma genitalium infection by culture is very slow and consequently molecular techniques are the only procedures that can provide relevant diagnostic information. For Treponema pallidum, molecular techniques can provide direct benefits in the diagnosis of infection. Molecular techniques are not established for the routine diagnosis of donovanosis, but can be recommended when performed by experts. Molecular methods are advisable in Haemophilus ducreyi, because of the difficulties of culture and its low sensitivity. In genital herpes, molecular techniques have begun to be recommended for routine diagnosis and could soon become the technique of choice. For other genital infections, bacterial vaginosis, vulvovaginal candidosis and trichomoniasis, diagnosis by molecular methods is poorly established. With genital warts, techniques available for screening and genotyping of endocervical samples could be used for certain populations, but are not validated for this purpose.

Detection and differentiation of human papillomavirus genotypes HPV-6 and HPV-11 by FRET-based real-time PCR

A real-time PCR (RT-PCR) assay was developed based on fluorescence resonance energy transfer (FRET) hybridization probe technology, allowing very sensitive and specific detection of HPV-6 and HPV-11, reliable differentiation of HPV-6 and HPV-11, as well as prototypic and non-prototypic HPV-6 genomic variants, in a single PCR reaction. The primers and probe were designed on the basis of multiple alignments of 74 HPV-6 E2 gene sequences and 20 HPV-11 E2 gene sequences. Testing on defined plasmid standards showed that the RT-PCR allowed simple and reliable identification of HPV-6 and HPV-11 using type specific amplification followed by probe-specific post-amplification dissociation analysis. Sensitivity, assessed by probit analysis at a 95% detection level, was 42.9, 43.4, and 25.3 DNA copies per assay for prototypic and non-prototypic HPV-6 variants and HPV-11, respectively. The results obtained by the developed assay on 51 HPV DNA-negative samples and 149 HPV DNA-positive samples, including 81 HPV-6 positive samples (19 prototypic and 62 non-prototypic HPV-6 variants), 28 HPV-11 positive samples, 10 samples of HPV-44 and HPV-74 (the closest relatives of HPV-6 and HPV-11) and 30 samples of 15 other important alpha HPV, showed complete agreement with those obtained with the INNO-LiPA human papillomavirus (HPV) Genotyping Assay and HPV-6 E2 and E6 gene sequencing.