FRET-based detection and genotyping of HPV-6 and HPV-11 causing recurrent respiratory papillomatosis

A Rapid, SuperSelective Method for Detection of Single Nucleotide Variants in Caenorhabditis elegans

With the widespread use of single nucleotide variants generated through mutagenesis screens and genome editing technologies, there is pressing need for an efficient and low-cost strategy to genotype single nucleotide substitutions. We have developed a rapid and inexpensive method for detection of point mutants through optimization of SuperSelective (SS) primers for end-point PCR in Caenorhabditis elegans Each SS primer consists of a 5' "anchor" that hybridizes to the template, followed by a noncomplementary "bridge," and a "foot" corresponding to the target allele. The foot sequence is short, such that a single mismatch at the terminal 3' nucleotide destabilizes primer binding and prevents extension, enabling discrimination of different alleles. We explored how length and sequence composition of each SS primer segment affected selectivity and efficiency in various genetic contexts in order to develop simple rules for primer design that allow for differentiation between alleles over a broad range of annealing temperatures. Manipulating bridge length affected amplification efficiency, while modifying the foot sequence altered discriminatory power. Changing the anchor position enabled SS primers to be used for genotyping in regions with sequences that are challenging for standard primer design. After defining primer design parameters, we demonstrated the utility of SS primers for genotyping crude C. elegans lysates, suggesting that this approach could also be used for SNP mapping and screening of CRISPR mutants. Further, since SS primers reliably detect point mutations, this method has potential for broad application in all genetic systems.

Juvenile-Onset Recurrent Respiratory Papillomatosis Diagnosis and Management - A Developing Country Review

Recurrent respiratory papillomatosis (RRP) is a condition caused by human papillomavirus (HPV), usually HPV types 6 and 11, which is characterized by recurrent papillomas of the respiratory tract, mainly the larynx. Patients usually present between the ages of 2 and 6 years. The initial presenting symptom is progressive dysphonia, followed by stridor and respiratory distress. Treatment consists of repeated microlaryngoscopic procedures to remove the papillomas as there is no cure. The poor availability and accessibility of appropriate healthcare services in developing countries are barriers to the early diagnosis and appropriate management of patients with juvenile-onset recurrent respiratory papillomatosis (JoRRP), requiring many patients to have a tracheostomy. The introduction of prophylactic vaccines that include HPV6 and HPV11 is necessary in order to reduce the incidence of JoRRP.

Cost-Utility Analysis of Human Papillomavirus Vaccination and Cervical Screening on Cervical Cancer Patient in Indonesia

BACKGROUND

Although cervical cancer is a preventable disease, the clinical and economic burdens of cervical cancer are still substantial issues in Indonesia.

OBJECTIVES

The main purpose of this study was to model the costs, clinical benefits, and cost-utility of both visual inspection with acetic acid (VIA) screening alone and human papillomavirus (HPV) vaccination in addition to VIA screening in Indonesia.

METHODS

We developed a population-based Markov model, consisting of three health states (susceptible, cervical cancer, and death), to assess future costs, health effects, and the cost-utility of cervical cancer prevention strategies in Indonesia. We followed a cohort of 100,000 females 12 to 100 years old and compared VIA screening alone with the addition of HPV vaccination on top of the screening to "no intervention."

RESULTS

The implementation of VIA screening alone and in combination with HPV vaccination would reduce the cervical cancer incidence by 7.9% and 58.5%, corresponding to 25 and 98 deaths avoided within the cohort of 100,000, respectively. We also estimated that HPV vaccination combined with VIA screening apparently yielded a lower incremental cost-effectiveness ratio at international dollar 1863/quality-adjusted life-year (QALY), compared with VIA screening alone (I$3126/QALY). Both strategies could however be definitely labeled as very cost-effective interventions, based on a threshold suggested by the World Health Organization. The incremental cost-effectiveness ratio was sensitive to the discount rate, cervical cancer treatment costs, and quality of life as part of the QALY.

CONCLUSIONS

The addition of HPV vaccination on top of VIA screening could be a cost-effective strategy in Indonesia even if relatively conservative assumptions are applied. This population-based model can be considered as an essential tool to inform decision makers on designing optimal strategies for cervical cancer prevention in Indonesia.

The cost-effectiveness of HPV vaccination in addition to screening: a Dutch perspective

Addition of the HPV vaccine to available cytological screening has been proposed to increase HPV-related cancer prevention. A comprehensive review on this combined strategy implemented in the Netherlands is lacking. For this review, we therefore analyzed all relevant studies on cost-effectiveness of HPV vaccines in combination with cervical screening in the Netherlands. Most of the studies agree that vaccination in pre-sexual-activity periods of life is cost-effective. Based on published sensitivity analyses, the incremental cost-effectiveness ratio was found to be mainly driven by vaccine cost and discount rates. Fewer vaccine doses, inclusion of additional benefits of these vaccines to prevent HPV-related non-cervical cancers and vaccination of males to further reduce the burden of HPV-induced cancers are three relevant options suggested to be investigated in upcoming economic evaluations.

Genomic diversity of human papillomaviruses (HPV) and clinical implications: an overview in adulthood and childhood

During the last years, several researchers have highlighted the importance of characterizing more than one genomic region in order to detect recombination and classify variants of human papillomaviruses (HPVs) properly. HPVs variants differ in their biological, molecular and chemical properties. Therefore, this genomic diversity can present differences in the natural history and pathogenicity of HPVs. Different 'high-risk' HPVs variants of the genotypes HPV 16 and 18 can confer varied risks of viral persistence in the human cervix and influence HPVs progression to cervical cancer. Moreover, different 'low-risk' HPVs variants of the genotypes HPV 6 and 11 can play a unique role in the development of anogenital and cutaneous warts, recurrent respiratory papillomatosis (RRP) and ophthalmic pterygium. In future, the precise impact of genomic HPVs diversity to the clinical course of HPVs-associated diseases as well as to the efficacy of the current HPVs vaccines remains to be elucidated.

HPV associated with recurrent respiratory papillomatosis

Papillomaviruses are members of the Papillomaviridae family. Over 150 HPV types have been identified. Recurrent respiratory papillomatosis (RRP) is a chronic condition caused by HPV characterized by recurrent papillomas of the respiratory tract, mainly the larynx. During the early stages, the condition presents with hoarseness, while more advanced disease presents with stridor and respiratory distress. There is no specific cure and treatment consists of repeated surgical procedures to remove the papillomas. Most patients eventually go into remission, but some suffer for many years with this condition, which may be fatal. HPV-6 and HPV-11 are the HPV types most commonly associated with RRP. Although most studies have found RRP due to HPV-11 to be more aggressive than disease due to HPV-6, the variability in disease aggressiveness is probably multifactorial. Information regarding the current epidemiology, molecular diversity and host immune responses is important for strategizing ways to reduce disease. Data on HPV genotypes associated with RRP would provide valuable information for vaccination programs to reduce the incidence of these genotypes in mothers and, in the long term, reduce the incidence of RRP in children. This review focuses on HPV-6 and HPV-11 as the HPV types that cause RRP, and discusses the viral genome and replication, clinical presentation of RRP, current techniques of diagnosis and genotyping, and the molecular diversity of HPV-6 and HPV-11.