Infection with Human Papillomavirus: Update on Epidemiology, Diagnosis, and Treatment

HLA Class II alleles and association with HPV Infection prevalence in high-risk HPV-positive Han women in southern China

OBJECTIVE

To investigate the prevalence of different human papillomavirus (HPV) subtypes and their association with human leukocyte antigen (HLA) class II alleles in China.

PATIENTS AND METHODS

A total of 16,168 married Chinese women in Maoming City of Guangdong province were tested for high-risk HPV infection. High-resolution typing of HLA-DRB1/DQB1 alleles was also performed on samples found to be infected with HPV.

RESULTS

All in all, HPV-52, -58, -16, -18, and -53 were the five most common subtypes of HPV, with an incidence of high-risk HPV infection of 7.14%. Among women at high-risk of HPV infection, -DRB1*0403 (3.12% vs. 1.67%, odds ratio [OR] 1.894), -DQB1*0602 (3.74% vs. 1.82%, OR 2.094), and -DQB1*0609 (2.02% vs. 0.91%, OR 2.249) frequencies were higher than in controls. In contrast, -DQB1*0402 (0.31% vs. 1.29%, OR 0.239) in women with high-risk HPV infection exhibited a significantly decreased frequency compared to the controls.

CONCLUSION

Our results strongly support previous findings from other populations that -DRB1*0403 and -DQB1*0602 may be risk factors for HPV infection and subsequent development of cervical cancer. Moreover, unlike the European population, -DQB1*0402 may protect rather than render Maoming women susceptible to HPV infection.

Blocking IL-10 signalling at the time of immunization renders the tumour more accessible to T cell infiltration in mice

We recently reported that blockade of IL-10 signalling at the time of a human papillomavirus (HPV) long E7 peptide/LPS immunization leads to the regression of established HPV-16 immortalized tumours in mice similar to that induced by long E7 peptide/incomplete Freund's adjuvant (IFA)-based vaccination. In this paper, we demonstrated that blockade of IL-10 signalling at the time of long E7 peptide/LPS could elicit stronger T cells responses and render the tumour more accessible for immune cell infiltration than vaccination with long E7 peptide/IFA. Furthermore, priming with long E7 peptide/LPS and IL10 signalling blockade then boosting with long E7 peptide/IFA elicits stronger CD8+ T cell responses than long E7 peptide/IFA immunization. The results suggest that priming with long E7 peptide/LPS and IL10 signalling inhibitor, then boosting with long E7 peptide/IFA elicits may lead to better HPV infection related tumour regression in clinic.

Seroepidemiology of human papillomavirus type 11 in the United States: results from the third National Health And Nutrition Examination Survey, 1991--1994

OBJECTIVES

The national seroprevalence of the nononcogenic human papillomavirus (HPV) type 11, one of the types targeted by the quadrivalent HPV vaccine, has not been evaluated in the United States. The objectives of this study were to estimate the national seroprevalence and evaluate predictors of HPV-11 seropositivity.

STUDY DESIGN

We tested serum samples for HPV-11 antibodies and analyzed questionnaire data from the second phase of the National Health and Nutrition Examination Survey III, 1991--1994. Seroprevalence estimates were weighted to represent the US population.

RESULTS

: Overall seroprevalence of HPV-11 infection was 4.7%. Seroprevalence was significantly higher among females (5.7%) than among males (3.6%). Independent predictors of HPV-11 seropositivity included sex, race/ethnicity, lifetime number of sex partners, education, and HPV-16 seropositivity.

CONCLUSION

This study represents the most comprehensive picture of HPV-11 infection in the United States to date, and provides baseline data on the prevalence of HPV-11 before availability of the quadrivalent HPV vaccine.

Warts, malnutrition, and sunshine

Viral warts are common in poor rural settings but their relationship to malnutrition has not been studied. We sought to determine the prevalence of warts in children of two communities in Oaxaca, Mexico, and compared it with their nutritional status. Children from Santa Catarina Yahuio and Santiago Laxopa of the state of Oaxaca were examined. Localization, number, and type of verruca were noted. Date of birth, height, and weight were obtained to determine nutritional status. A total of 213 children (116 girls and 97 boys), 107 in Yahuio and 106 in Laxopa, were studied. Mean age was 10.24 years. Thirty children (14.1%) had warts and 80% (24/30) of these lived in Yahuio (p = 0.0002). Almost half were teenagers. Most lesions were on sun-exposed areas. First degree malnutrition was found in 24.5%; second degree in 23.6% and third degree in 14.2%. A higher frequency of warts than previously reported was found. Malnutrition was prevalent in both groups but did not correlate positively with verruca. Verruca were more frequent in females, adolescents, sun-exposed areas, and higher altitude. We believe that the higher altitude of Yahuio facilitates greater exposure to ultraviolet light-induced immune suppression.

Management of potentially malignant disorders: evidence and critique

At a workshop coordinated by the WHO Collaborating Centre of Oral Cancer and Precancer in the United Kingdom, issues related to management of patients affected by oral leukoplakia were discussed by an expert group. The consensus views of the working group are presented here. Although removal of a lesion still seems to be the predominant method of treatment by the majority of relevant health care professionals, no randomized controlled trials have been undertaken to test the hypothesis that excision either by scalpel or laser greatly influences the potential for later malignant transformation within the oral mucosa of an affected individual. Results of observational studies indicate that, although surgery may have a beneficial effect, this is not likely to reduce the risk of later recurrence nor malignant transformation at the same or another site. Medical measures that lessen the size, extent or histopathological features of dysplasia within leukoplakia likewise presently do not seem to be of particular promise, as relapse or later malignant transformation can occur, and there is a risk of adverse effects, particularly with systemic agents (which themselves may be contra-indicated in some individuals). While the risk of malignant transformation, and the development of further potentially malignant disease may theoretically be reduced by cessation of risk activities, such as tobacco usage and alcohol consumption, there remain no good studies that demonstrate that such measures significantly reduce such events.

Human papillomavirus infection in the etiology of laryngeal carcinoma

PURPOSE OF REVIEW

One fifth of cancers worldwide are associated with viral infection. Indeed, the causal link between human papillomavirus and cervical carcinoma is so well established that it is thought to be the first necessary cause of human cancer ever identified. One of the primary aims of research in this area is to reduce cancer prevalence by vaccination. However, the role that human papillomavirus plays in carcinogenesis of the head and neck region may also have important implications for its prevention and treatment.

RECENT FINDINGS

Although human papillomavirus was first identified in the larynx 20 years ago, the extent to which it is present in epithelium of the normal population is unclear. Laryngeal papillomas are the most common benign tumors in the larynx. They are associated with a small risk (3 to 7%) of malignant transformation, in which smoking and irradiation appear to be cofactors. The search for alternate risk factors for the development of laryngeal cancer, particularly in those who are nonsmokers and nondrinkers, has led to the hypothesis that human papillomavirus may have a pivotal role. Epidemiologic studies, although not conclusive, strongly suggest its involvement in the etiology of a subset of laryngeal carcinomas. Recent molecular evidence supports this.

SUMMARY

An adequately powered, multicenter case-control study is required to elucidate the full extent of this association and to examine the relation between the virus and other risk factors.

HLA-DRB1*1602 allele is positively associated with HPV cervical infection in Bolivian Andean women

Incidence of cervical cancer is high among Bolivian Andean women. Human papillomavirus (HPV) infection is known as the major risk factor of cervical cancer. The host immune system plays an important role in the outcome of HPV infection and associated malignancies. In order to study the immunogenetic background of Bolivian Andean women with regard to HPV infection status, we compared HLA class I and class II allele frequencies between 37 HPV positive and 68 HPV negative Bolivian women. Demographic variables, including distribution of Andean ethnicities, were similar in both groups. Comparison of HLA class I allele frequencies between both groups indicated no significant difference. In contrast, HLA class II DRB1*1602 allele, an Amerindian allele, was significantly higher in the HPV positive women compared with HPV negative controls (chi(2) = 5.2, p < 0.05, odds ratio = 3.17; 95% confidence interval = 1.4-8.8). HPV types present in the HPV positive group were HPV-18, -16, -31, -33, and -58. These results suggest that HLA class II DRB1*1602 may confer susceptibility to infection with genetically related HPV types. This is the first report of an HLA class II association with HPV infection in an Andean population.

Human papillomavirus and cervical cancer: not just a sexually transmitted disease

The human papillomavirus (HPV) is the cause of virtually all cancers of the cervix, the fourth most common cancer in women in the United States. HPV is sexually transmitted, and the lifetime risk of contracting the virus is estimated to be 75%-90%. New methods of detecting HPV infection and cellular changes (dysplasia) caused by HPV can greatly reduce the mortality associated with this virus. More than 100 types of HPV exist and may be classified as low-, intermediate-, or high-risk in terms of causing cancer. The virus can cause genital warts, subclinical dysplasia, and cancer. Nurses play an important role in educating patients regarding HPV and preventive measures as well as in screening and treatment. Most women diagnosed with HPV need emotional support and factual information provided in a supportive, nonjudgmental manner. Nurses can meet this challenge and make a difference in reducing the incidence and mortality of cervical cancer.

Prevalence of human papillomavirus infection in rural villages of the Bolivian Amazon

Cervical cancer constitutes a major health problem in developing countries like Bolivia. The roles of certain genotypes of human papillomaviruses (HPVs) in the pathogenesis of cervical cancer is well established. The prevalence of HPV infection among sexually active women varies greatly. Information regarding HPV infection in Bolivia is very much scarce, specially in regions like the Amazonian lowland. We studied 135 healthy women living in four rural localities of the Bolivian Amazon. Presence of HPV in DNA extracted from cervical swabs was analyzed using a reverse line hybridization assay. The estimated overall HPV infection prevalence among the studied rural localities was 5.9% (ranging from 0-16.6%). These values were unexpectedly low considering Bolivia has a high incidence of cervical cancer. The fact that Amazonian people seem to be less exposed to HPV, makes it likely that some other risk factors including host lifestyle behaviors and genetic background may be involved in the development of cervical cancer in this population.