Prevention of human papillomavirus (HPV)-related tumors in people living with human immunodeficiency virus (HIV)

Introduction: In comparison to their HIV-negative counterparts, people living with HIV (PLWH) have a higher prevalence of human papillomavirus (HPV) infection in various anatomical sites coupled with increased HPV persistence, higher risk of HPV-related tumors, and faster disease progression.

Areas covered: Gender-neutral prevention strategies for HPV-related cancers in PLWH discussed: ABC approach, HPV vaccination, antiretroviral treatment (ART), anal cancer screening, and smoking cessation. Gender specific strategies: cervical cancer screening reduces the incidence and mortality of cervical cancer and circumcision might reduce the risk of HPV infections in men.

Expert commentary: HPV-related cancer incidence has not declined (e.g. cervical cancer) and has even increased (e.g. anal cancer) in the ART era, demanding an effective HPV prevention strategy. HPV vaccination should be introduced into national prevention programs worldwide immediately because current prophylactic vaccines are safe, tolerable, and immunogenic in PLWH. HPV vaccine efficacy trials in PLWH are essential to determine the most appropriate immunization schedule. The population most at risk of anal cancer is HIV-positive men who have sex with men, who are not protected by herd immunity if only the female population is vaccinated. Unvaccinated PLWH need enhanced surveillance for early detection of HPV-related cancers and their precursors.     

Human Papillomavirus Genotype Specificity of Hybrid Capture 2 Low-Risk Probe Cocktail

A genotyping study of 285 Hybrid Capture 2 low-risk probe cocktail-positive specimens showed cross-reactivity with several untargeted human papillomavirus genotypes. Cross-reactivity was often clinically beneficial due to the detection of untargeted low-risk genotypes. A total of 8.4% of positive results, usually weak, were due to cross-reactivity with high-risk genotypes. Establishment of a gray zone is recommended.Low-risk alpha-human papillomaviruses (HPV) have never been at the fore in HPV research, due to their connection with benign neoplasm only. However, interest in these genotypes has increased substantially in recent years, due to the fact that quadrivalent HPV vaccine contains, in addition to a “cervical cancer component” (against HPV16 and HPV18), virus-like particles of the two most important low-risk alpha-HPV genotypes: HPV6 and HPV11. These two closely related HPV genotypes are the etiological agents of at least 90% of genital warts and laryngeal papillomas (1, 8, 10, 20) and at least 12.1% of cervical low-risk squamous intraepithelial lesions (5). In phase III clinical trials, this quadrivalent prophylactic HPV vaccine was shown to be highly effective against genital warts, e.g., reducing the burden of genital warts by 99% (95% confidence interval = 93.7 to 100%) among HPV-naïve vaccinated women aged 16 to 26 years (11). The quadrivalent HPV vaccine is currently licensed in more than 105 countries and has already been included in national vaccination programs in several countries. The widespread use of this vaccine has created an immediate need for a very specific detection tool for low-risk alpha-HPV.The Hybrid Capture 2 HPV DNA test (hc2), originally developed by Digene Corporation (Gaithersburg, MD) and currently marketed by Qiagen (Hilden, Germany), is the most widely used molecular method for the detection of a subset of clinically important HPV genotypes (14-16, 18). In this assay, exfoliated cells are first treated with alkali-denaturing reagent, and the processed samples are hybridized under high-stringency conditions with two mixtures of unlabeled full-genomic-length RNA probes, one specific for 13 high-risk HPV genotypes (HPV16, HPV18, HPV31, HPV33, HPV35, HPV39, HPV45, HPV51, HPV52, HPV56, HPV58, HPV59, and HPV68) and one for 5 low-risk HPV genotypes (HPV6, HPV11, HPV42, HPV43, and HPV44). Positive specimens are detected by binding the hybridization complexes onto the surface of a microplate well coated with monoclonal antibodies specific to RNA-DNA hybrids. Immobilized hybrids are detected by the addition of an alkaline phosphatase-conjugated antibody to RNA-DNA hybrids, followed by the addition of a chemiluminiscent substrate. The emission of light is measured as relative light units (RLU) in a luminometer. Thus, hc2 does not allow the exact determination of HPV genotype(s) present in a clinical specimen but rather expresses the results of tested high-risk or low-risk HPV genotypes as positive or negative. The hc2 high-risk cocktail is very reliable for the routine detection of clinically important HPV infection and is, at present, the only commercially available HPV DNA assay with sufficient scientific data to support its performance in a clinical setting. However, several studies have shown significant analytical inaccuracy of the high-risk cocktail, mainly due to cross-reactivity with several untargeted HPV genotypes (2-4, 6, 9, 16, 19, 21-26, 27). This phenomenon certainly reduces the analytical specificity of the high-risk cocktail, but cross-reactivity with some HPV genotypes has proven to be clinically beneficial (4, 19).The U.S. version of hc2, containing the high-risk probe cocktail only, is approved by the U.S. Food and Drug Administration (FDA) for triage (in cases of equivocal cytology results showing the presence of atypical squamous cells of undetermined significance) to determine which patients should be referred to physicians for a colposcopy and as a screening test for use in addition to cytology screening for women 30 years of age and older (15). Although the use of the hc2 low-risk probe cocktail is not recommended in the U.S. due to lack of FDA approval, the “Conformité Européene” (CE)-certified version of hc2, containing both high-risk and low-risk probe cocktails, is currently used in at least 40% of laboratories outside the U.S., mainly for individuals with clinically suspected low-risk HPV infection or as a reflex test for women with atypical squamous cells of undetermined significance who tested negative for high-risk HPVs. In contrast to the established cross-reactivity of the high-risk probe cocktail with several untargeted HPV genotypes, the specificity of the hc2 low-risk cocktail has never been studied in detail. According to the data presented in the hc2 package insert, the only recognized cross-reactivity of the hc2 low-risk cocktail is with HPV13, a genotype commonly detected in lip lesions of certain ethnic groups but never in anogenital lesions (17). In the present study, therefore, we have for the first time systematically examined the analytical specificity of the hc2 low-risk cocktail by determining the exact HPV genotype(s) present in 285 consecutive samples recognized using the hc2 low-risk probe cocktail as HPV DNA positive.To determine the specificity and accuracy of hc2 in the detection of the five HPV genotypes (HPV6, HPV11, HPV42, HPV43, and HPV44) included in the low-risk probe cocktail, 285 consecutive cervical specimens obtained from the same number of women and recognized as HPV positive using the hc2 low-risk probe cocktail were included in the study. Fifty-six out of 285 samples were positive using both low-risk and high-risk probe cocktails. The specimens included in the study were collected between June 2007 and May 2008, using a DNAPaP cervical sampler and specimen transport medium (STM; Digene Corporation, Gaithersburg, MD), from Croatian and Slovenian women undergoing routine gynecological examination. hc2 testing was performed not later than 5 days after the collection of specimens, strictly following the manufacturer''s instructions. According to the manufacturer''s interpretation criteria, the specimens with a RLU-per-cutoff (RLU/CO) value higher than 1.0 were considered positive for one or more low-risk HPV genotypes included in the cocktail, and the specimens with a RLU/CO value of <1.0 were considered negative for the five low-risk HPV genotypes tested.The presence of the five targeted low-risk genotypes, as well as other, untargeted low-risk and high-risk HPV genotypes, in the hc2 low-risk cocktail-positive samples was determined by using seven different PCR-based genotyping methods. To keep the number of tests to a minimum, the seven methods were used consecutively, e.g., if the first genotyping method reliably detected at least one of the five targeted HPV genotypes in the particular hc2 low-risk cocktail-positive sample, this sample was excluded from further testing. All seven genotyping tests were performed on the same sample used for hc2 testing, i.e., 500 μl of STM was removed before the addition of hc2 denaturing reagent solution (first step of hc2 testing) and kept at −70°C until genotyping. After the isolation of DNA from 200 μl of nondenatured STM using a QIAamp DNA mini kit (Qiagen, Hilden, Germany), all 285 samples were first tested using a recently developed real-time PCR (RT-PCR) assay that allows very specific detection and reliable differentiation of HPV6 and HPV11 (13). The sensitivity of the test, assessed by probit analysis at a 95% detection level, is 42.9, 43.4, and 25.3 DNA copies per assay for prototypic and nonprototypic HPV6 variants and HPV11, respectively (13). Sixty-six samples were found to be positive for HPV6, and 6 samples contained HPV11 (Table ​(Table1).1). The remaining 213 samples were then tested using HPV42 genotype-specific RT-PCR, and 105 were found to contain this low-risk HPV. The remaining 108 samples were then tested using HPV43 genotype-specific RT-PCR, followed by testing of all negative samples using HPV44/55 genotype-specific RT-PCR. By using the two RT-PCR tests, the presence of HPV43 and HPV44/55 was identified in 8 and 17 samples, respectively (Table ​(Table1).1). The HPV42, HPV43, and HPV44/55 genotype-specific primers and probes were designed according to the L1 long control region genomic sequences of the prototype isolates (GenBank accession nos. {"type":"entrez-nucleotide","attrs":{"text":"M73236","term_id":"333211","term_text":"M73236"}}M73236, {"type":"entrez-nucleotide","attrs":{"text":"AJ620205","term_id":"40804474","term_text":"AJ620205"}}AJ620205, {"type":"entrez-nucleotide","attrs":{"text":"U31788","term_id":"1020242","term_text":"U31788"}}U31788, and {"type":"entrez-nucleotide","attrs":{"text":"U31791","term_id":"1020266","term_text":"U31791"}}U31791, respectively). As shown in Table ​Table2,2, two primers and two hybridization (fluorescent resonance energy transfer) probes were selected for each HPV genotype studied. A common probe was designed for HPV44 and HPV55, which has recently been recognized as a subtype of HPV44 and is no longer considered a separate genotype (7). A BLAST search of the GenBank nr database was performed for each sequence in order to verify HPV genotype specificity. The assays were set up on a LightCycler 2.0 real-time system (Roche Diagnostics GmbH, Mannheim, Germany) and performed using a QuantiTect probe PCR kit (Qiagen, Hilden, Germany) according to the manufacturer''s instructions.

TABLE 1.

Summary of genotyping results of 285 consecutive samples recognized as HPV DNA positive using the hc2 low-risk probe cocktail

Ankle-brachial index and ocular diseases in a Russian population

BackgroundTo assess potential associations between the ankle-brachial blood pressure index (ABI) and ocular disorders.MethodsIn the population-based cross-sectional Russian Ural Eye and Medical Study including 5,899 (80.5%) out of 7328 eligible participants aged 40+ years, the participants underwent a series of ocular and medical examinations including measurement of ABI.ResultsBlood pressure measurements of both arms and ankles were available for 3187 (54.0%) individuals. The mean ABI was 1.26 ± 0.19 (median:1.20; range: 0.61, 2.20). In multivariate analysis, a higher ABI was associated with younger age (P < 0.001; non-standardized regression coefficient B: −0.001; 95% confidence interval (CI): −0.002, −0.001), female sex (P < 0.001; B: 0.03; 95% CI: 0.02, 0.04), lower body mass index (P < 0.001; B: −0.004; 95% CI: −0.006, −0.003), lower waist-to-hip ratio (P = 0.01; B: −0.10; 95% CI: −0.17, −0.02), lower glucose serum concentration (P = 0.008; B: −0.005; 95% CI: −0.009, −0.001), lower prevalence of arterial hypertension (P < 0.001; B: −0.14; 95% CI: −0.16, −0.12), higher mean systolic blood pressure (P < 0.001; B: 0.003; 95% CI: 0.002, 0.003), and higher prevalence of any alcohol consumption (P < 0.001; B: 0.03; 95% CI: 0.02, 0.04). In that multivariate model, prevalence of glaucoma (P = 0.67) as a whole, open-angle glaucoma (P = 0.86) and angle-closure glaucoma (P = 0.54), stage of glaucomatous optic neuropathy (P = 0.57), prevalence of age-related macular degeneration (P = 0.88), prevalence and stage of diabetic retinopathy (P = 0.30, and P = 0.29, respectively), nuclear cataract (P = 0.32, and P = 0.41, resp.), cortical cataract (P = 0.33, and P = 0.92, resp.), subcapsular cataract (P = 0.74 and P = 0.60, resp.), and pseudoexfoliation (P = 0.44 and P = 0.47, resp.), intraocular pressure (P = 0.52), axial length (P = 0.20), and peripapillary retinal nerve fibre layer thickness (P = 0.55) were not significantly associated with the ABI.ConclusionsIn this ethnically mixed population from Russia, none of the major ocular diseases was associated with ABI suggesting that subclinical atherosclerosis is not markedly associated with the aetiology of these ocular disorders.Subject terms: Retinal diseases, Lens diseases     

Cold Agglutinin Induced Hemolysis in a Newly Diagnosed Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a well-known autoimmune chronic inflammatory disease, which can virtually affect any organ system in the body. Although hemolytic anemia has been known to occur in < 10% of SLE patients, they are usually mediated through warm antibodies. It is extremely rare to see cold antibody-mediated hemolytic anemia in SLE, and only few cases have been reported in literature to our knowledge. This is a unique case report of SLE associated with cold agglutinin hemolytic anemia in a patient presented with generalized tender lymphadenopathy and typical B-symptoms including fever, night sweats, and significant weight loss.     

Accuracy of genotyping for HPV16 and 18 to triage women with low-grade squamous intraepithelial lesions: a pooled analysis of VALGENT studies

Background: Genotyping for the most carcinogenic human papillomavirus (HPV) types (HPV16/HPV18) can identify high risk of underlying cervical precancer and guide further management.

Research design and methods: A pooled analysis was performed of the clinical accuracy of high-risk HPV (hrHPV) testing and HPV16/18 genotyping in triage of women with low-grade squamous intraepithelial lesions (LSIL). Data regarding 24 assays evaluated in four VALGENT validation panels were used.

Results: In women with LSIL, hrHPV had a pooled sensitivity for CIN2+ of 95.5% (95% CI: 91.0–97.8%) and a specificity of 25.3% (95% CI: 22.2–28.6%). HPV16/18 genotyping had a sensitivity and specificity for CIN2+ of 52.9% (95% CI: 48.4–57.4%) and 83.5% (95% CI: 79.9–86.5%), respectively. The average risk of CIN2+ was 46.1% when HPV16/18-positive, 15.5% in women who were HPV16/18-negative but positive for other hrHPV types and 4.3% for hrHPV-negative women.

Conclusions: Triage of women with LSIL with HPV16/18 genotyping increases the positive predictive value compared to hrHPV testing but at the expense of lower sensitivity. Arguably, women testing positive for HPV16/18 need further clinical work-up. Whether colposcopy referral or further surveillance is recommended for women with other hrHPV types may depend on the post-test risk of precancer and the local risk-based decision thresholds.     

Metallization-Induced Quantum Limits of Contact Resistance in Graphene Nanoribbons with One-Dimensional Contacts

Graphene has attracted a lot of interest as a potential replacement for silicon in future integrated circuits due to its remarkable electronic and transport properties. In order to meet technology requirements for an acceptable bandgap, graphene needs to be patterned into graphene nanoribbons (GNRs), while one-dimensional (1D) edge metal contacts (MCs) are needed to allow for the encapsulation and preservation of the transport properties. While the properties of GNRs with ideal contacts have been studied extensively, little is known about the electronic and transport properties of GNRs with 1D edge MCs, including contact resistance (R_C), which is one of the key device parameters. In this work, we employ atomistic quantum transport simulations of GNRs with MCs modeled with the wide-band limit (WBL) approach to explore their metallization effects and contact resistance. By studying density of states (DOS), transmission and conductance, we find that metallization decreases transmission and conductance, and either enlarges or diminishes the transport gap depending on GNR dimensions. We calculate the intrinsic quantum limit of width-normalized R_C and find that the limit depends on GNR dimensions, decreasing with width downscaling to ~21 Ω∙µm in 0.4 nm-wide GNRs, and increasing with length downscaling up to ~196 Ω∙µm in 5 nm-long GNRs. We demonstrate that 1D edge contacts and size engineering can be used to tune the R_C in GNRs to values lower than those of graphene.