Human Immunodeficiency Virus and Human Papilloma Virus - why HPV-induced lesions do not spontaneously resolve and why therapeutic vaccination can be successful

Regulatory T cell frequency in peripheral blood of women with advanced cervical Cancer including women living with HIV

BACKGROUND

Persistent high-risk Human papillomavirus (HR-HPV) infections are the main cause of cervical cancer. Cumulative evidence implicates regulatory T cells (Tregs) as a critical factor in the failure to eliminate HPV-induced cancers leading to their persistence and progression to cancer. Also, the WHO recognised cervical cancer as 100% attributable to persistent HR-HPV infection. The province of KwaZulu-Natal (KZN) in South Africa has a high prevalence of cervical cancer and HIV infection.

MATERIALS AND METHODS

We evaluated Treg frequency in dual infection of HR HPV and HIV coinfection using phenotypic markers, CD4, CD25 and intracellular Foxp3, in the peripheral blood of 51 cervical cancer and 46 non-cervical cancer participants and evaluated the effect of HIV on regulatory T cell proportion. Peripheral blood mononuclear cells were surface stained with a cocktail fluorescent labelled CD4 and CD25 and subsequently with APC anti-human FoxP3 (eBioscience). Flow cytometry was performed with FACS analysis. Statistical analysis of results was done using Instat 3 program (GraphpadR). Tregs results were expressed as median ± interquartile range (IQR). Associations of cervical cancer with demographic, clinical and laboratory variables were evaluated by univariate and multivariate logistic regression analysis using SPSS version 27 (IBM).

RESULTS

Tregs frequency was significantly higher in individuals with cervical cancer (11.00 ± 19.79%) compared to controls (1.71 ± 8.91%) (p < 0.0001). HIV infection was associated with an increase in Tregs frequency. In controls a significant difference in Tregs frequency was noted between women living with HIV (6.00 ± 10.57%, n = 9) and those without HIV (1.30 ± 6.10%, n = 37), p = 0.0023. In multivariate logistic regression, Tregs frequency was significantly associated with cervical cancer after controlling for age, smoking, weight loss, presence of STI, HIV and HPV genotype.

DISCUSSION/CONCLUSION

Higher Tregs frequency was significantly associated with cervical cancer highlighting the immunosuppressive role of Tregs in cervical cancer. Treg frequency was more strongly associated with cervical cancer than HIV infection. We provide baseline data for monitoring Treg frequencies in response to new preventive and therapeutic strategies in the management of cervical cancer.

New Perspectives in Therapeutic Vaccines for HPV: A Critical Review

Human Papillomavirus is the main cause of cervical cancer, including squamous cell carcinoma of the oropharynx, anus, rectum, penis, vagina, and vulva. In recent years, considerable effort has been made to control HPV-induced diseases using either prophylactic or therapeutic approaches. A critical review of the literature about the therapeutic Human Papillomavirus vaccine was performed to analyze its efficacy in the treatment of female lower genital tract lesions and its possible perspective application in clinical practice. The most important medical databases were consulted, and all papers published from 2000 until 2021 were considered. We retrieved a group of seven papers, reporting the role of anti HPV therapeutic vaccines against the L2 protein in the order of their efficacy and safety in female lower genital tract disease. In addition, the immune response due to vaccine administration was evaluated. The development of therapeutic vaccines represents an interesting challenge for the treatment of HPV infection of the lower genital tract. Literature data underline that the L2 protein may be an interesting and promising target in the development of therapeutic HPV vaccines, but the possible strengths and the unclear longevity of L2 immune responses are factors to be considered before clinical use.

Like Brothers in Arms: How Hormonal Stimuli and Changes in the Metabolism Signaling Cooperate, Leading HPV Infection to Drive the Onset of Cervical Cancer

Despite all precautionary actions and the possibility of using vaccinations to counteract infections caused by human papillomaviruses (HPVs), HPV-related cancers still account for approximately 5% of all carcinomas. Worldwide, many women are still excluded from adequate health care due to their social position and origin. Therefore, immense efforts in research and therapy are still required to counteract the challenges that this disease entails. The special thing about an HPV infection is that it is not only able to trick the immune system in a sophisticated way, but also, through genetic integration into the host genome, to use all the resources available to the host cells to complete the replication cycle of the virus without activating the alarm mechanisms of immune recognition and elimination. The mechanisms utilized by the virus are the metabolic, immune, and hormonal signaling pathways that it manipulates. Since the virus is dependent on replication enzymes of the host cells, it also intervenes in the cell cycle of the differentiating keratinocytes and shifts their terminal differentiation to the uppermost layers of the squamocolumnar transformation zone (TZ) of the cervix. The individual signaling pathways are closely related and equally important not only for the successful replication of the virus but also for the onset of cervical cancer. We will therefore analyze the effects of HPV infection on metabolic signaling, as well as changes in hormonal and immune signaling in the tumor and its microenvironment to understand how each level of signaling interacts to promote tumorigenesis of cervical cancer.

Importance of the Immune Microenvironment in the Spontaneous Regression of Cervical Squamous Intraepithelial Lesions (cSIL) and Implications for Immunotherapy

Cervical high-grade squamous intraepithelial lesions (cHSILs) develop as a result of a persistent high-risk human papilloma virus (hrHPV) infection. The natural course of cHSIL is hard to predict, depending on a multitude of viral, clinical, and immunological factors. Local immunity is pivotal in the pathogenesis, spontaneous regression, and progression of cervical dysplasia; however, the underlying mechanisms are unknown. The aim of this review is to outline the changes in the immune microenvironment in spontaneous regression, persistence, and responses to (immuno)therapy. In lesion persistence and progression, the immune microenvironment of cHSIL is characterized by a lack of intraepithelial CD3+, CD4+, and CD8+ T cell infiltrates and Langerhans cells compared to the normal epithelium and by an increased number of CD25+FoxP3+ regulatory T cells (Tregs) and CD163+ M2 macrophages. Spontaneous regression is characterized by low numbers of Tregs, more intraepithelial CD8+ T cells, and a high CD4+/CD25+ T cell ratio. A ‘hot’ immune microenvironment appears to be essential for spontaneous regression of cHSIL. Moreover, immunotherapy, such as imiquimod and therapeutic HPV vaccination, may enhance a preexisting pro-inflammatory immune environment contributing to lesion regression. The preexisting immune composition may reflect the potential for lesion regression, leading to a possible immune biomarker for immunotherapy in cHSILs.

Prevalence of human papillomavirus infection in Brazilian women living with HIV: a systematic review and meta-analysis

OBJECTIVE

We systematically investigated the prevalence of HPV, high-risk HPV and its genotypes in women living with human immunodeficiency virus (WLHIV) in Brazil.

METHODS

A systematic search was performed up to 15 December 2020. We included studies that used molecular methods for HPV detection in cervical samples and reported the prevalence of HPV in Brazilian WLHIV. The pooled prevalence of HPV, high-risk HPV (HR HPV) and HPV types and their 95% confidence interval (CI) were estimated. Subgroup analyses and meta-regression were conducted.

RESULTS

Thity-seven studies accounting for 8,436 WLHIV were included. The pooled HPV prevalence was 62% (95%CI 55-68%; I² = 96.98%; P < 0.001). Prevalence of high-risk HPV was 40% (95%CI, 54-68%; I² = 94.23%; P < 0.001). We found a wide variety of high-risk HPV genotypes. The high-risk HPV types most reported were HPV 16 (16%) and HPV 58 (6%). We found an increasing ratio of positivity from normal cervix to cancer. There were different factors associated with high-risk HPV, with low CD4+ count the most frequent.

CONCLUSION

The increase in the ratio of high-risk HPV positivity from normal cervix to carcinogenic lesions highlights the need to implement well-established testing for high-risk HPV in this population.

Antiretroviral Therapy and Detection of High-grade Cervical Intraepithelial Neoplasia (CIN2+) at Post-CIN Management Follow-up Among Women Living With Human Immunodeficiency Virus: A Systematic Review and Meta-Analysis

BACKGROUND

We evaluated the association of antiretroviral therapy (ART), CD4+ count and human immunodeficiency virus (HIV) plasma viral load (PVL) on high-grade cervical intraepithelial neoplasia (CIN2+) detection at follow-up after CIN management among women living with HIV (WLHIV).

METHODS

Medline, Embase, Global Health, and PubMed were searched from 1 January 1996 to 15 January 2020. Eligible studies investigated the association of ART, CD4+ count, or HIV PVL on histology-confirmed CIN2+ detection at follow-up. Summary estimates were obtained using random-effects meta-analyses; heterogeneity was examined using I2 statistic. PROSPERO registration: CRD42018115631.

RESULTS

Eight studies representing 9 populations were identified, including 1452 WLHIV followed between 6 and 33 months post-CIN management. Pooled data from 8 populations (n = 1408) suggested weak evidence of a decreased risk of CIN2+ detection at follow-up among ART users compared to ART-naive women (crude odds ratio [cOR] = 0.70, 95% confidence interval [CI]: .36-1.36; I2 = 64.5%, P = .006; adjusted risk ratio [aRR] from 3 studies = 0.66, 95% CI: .20-2.24; I2 = 78.7%, P = .009). A significant association was observed in high-income countries (cOR = 0.24, 95% CI: .13-.45; I2 = 0.0%, P = .77) but not in low and middle-income countries (cOR = 1.13, 95% CI: .67-1.92; I2 = 18.8%, P = .30).In 3 populations, ART users with HIV PVL <50 copies/ml were less likely to have CIN2+ detection at follow-up (vs ≥50 copies/mL: cOR = 0.55, 95% CI: .32-.94; I2 = 0.0%, P = .23).There was weak evidence of decreased CIN2+ detection at follow-up among WLHIV with higher contemporary CD4+ cell counts (≥200 cells/µL vs <200 cells/µL [cOR = 0.36, 95% CI: .04-3.13; I2 = 81.3%, P = .021]) and significant evidence among women with a higher nadir CD4+ count (≥350 cells/µl vs <200 cells/µl [adjusted hazard ratio [aHR] = 0.35, 95% CI: .15-.84; I2 = 0%, P = .64]).

CONCLUSION

ART may reduce the risk of CIN2+ detection at follow-up; this effect is most likely enhanced by a combination of adequate HIV control and excisional CIN treatment. Our findings support recommendations of early ART and the integration of CIN2+ screening and management into HIV care.

HPV and Other Microbiota; Who's Good and Who's Bad: Effects of the Microbial Environment on the Development of Cervical Cancer-A Non-Systematic Review

Cervical cancer is responsible for around 5% of all human cancers worldwide. It develops almost exclusively from an unsolved, persistent infection of the squamocolumnar transformation zone between the endo- and ecto-cervix with various high-risk (HR) human papillomaviruses (HPVs). The decisive turning point on the way to persistent HPV infection and malignant transformation is an immune system weakened by pathobionts and oxidative stress and an injury to the cervical mucosa, often caused by sexual activities. Through these injury and healing processes, HPV viruses, hijacking activated keratinocytes, move into the basal layers of the cervical epithelium and then continue their development towards the distal prickle cell layer (Stratum spinosum). The microbial microenvironment of the cervical tissue determines the tissue homeostasis and the integrity of the protective mucous layer through the maintenance of a healthy immune and metabolic signalling. Pathological microorganisms and the resulting dysbiosis disturb this signalling. Thus, pathological inflammatory reactions occur, which manifest the HPV infection. About 90% of all women contract an HPV infection in the course of their lives. In about 10% of cases, the virus persists and cervical intra-epithelial neoplasia (CIN) develops. Approximately 1% of women with a high-risk HPV infection incur a cervical carcinoma after 10 to 20 years. In this non-systematic review article, we summarise how the sexually and microbial mediated pathogenesis of the cervix proceeds through aberrant immune and metabolism signalling via CIN to cervical carcinoma. We show how both the virus and the cancer benefit from the same changes in the immune and metabolic environment.

Human immunodeficiency virus is a driven factor of human papilloma virus among women: evidence from a cross-sectional analysis in Yaoundé, Cameroon

BACKGROUND

Human papillomavirus (HPV) is the leading cause of cervical cancers, causing 270.000 deaths annually worldwide of which 85% occur in developing countries with an increasing risk associated to HIV infection. This study aimed at comparing HPV's positivity and genotype distribution in women according to their HIV status and determinants.

METHODS

A comparative study was carried out in 2012 at the Chantal BIYA International Reference Centre (CIRCB) among 278 women enrolled consecutively at the General Hospital and the Gynaeco-Obstetric and Paediatric Hospital of the City of Yaoundé. HPV genotyping was performed by real-time PCR, HIV serological screening by serial algorithm, CD4 T cell phenotyping by flow cytometry and HIV viral load by Abbott m2000RT. Statistical analyses were performed using Microsoft Excel 2016 and Graph Pad version 6.0 software; with P < 0.05 considered statistically significant.

RESULTS

Globally, mean age was 37 ± 3 years; median CD4-count for HIV+ was 414 cells/mm3 [IQR: 264.75-588] and median viremia was 50 RNA copies/mL [IQR: < 40-8288]. Overall HPV rate was 38.49% (107/278); 58.88% for single women vs. others (28.97% married, 2.80% divorced, 9.34% for widows), OR: 2.164; p = 0.0319. Following HIV status, HPV rate was 43.48% (80/184) among HIV+ vs. 28.72% (27/94) among HIV- (OR: 1.937; p < 0.0142); HPV genotypes among HIV+ vs. HIV- were respectively distributed as follows: genotype 16 (3.75% vs. 0.00%, p = 0.57), genotype 18 (3.75% vs. 3.70%, p = 1.00), co-infection 16 and others (8.75% vs. 7.40%, p = 1.00), co-infection 18 and others (8.75% vs. 11.11%, p = 0.71), co-infection 16, 18 and others (2.50% vs. 0.00%, p = 1.00) and other genotypes (72.50% vs. 77.78%, p = 0.80). Among HIV+ participants, HPV rate following CD4 was 62.88% (61/97) for CD4 < 500 vs. 35.71% (20/56) for CD4 ≥ 500 (OR: 3.05; p = 0.0012) while HPV rate following HIV viremia was 42.71% (41/96) with < 1000 RNA copies/ml vs. 66.00% (33/50) with > 1000 RNA copies/ml (OR = 0.384; p = 0.009).

CONCLUSION

In Yaoundé, HPV rate appear to be very high, with higher rates of genotypes other than 16 and 18. In the event of HIV infection, the risk of HPV positivity is two times higher, favoured essentially by immunodeficiency. Thus, HIV-infected women should be closely monitored to prevent the emergence of cervical cancer.

AIDS-Associated Malignancies

Malignancies were one of the earliest recognized manifestations that led to the description of the acquired immune deficiency syndrome (AIDS). The majority of cancers in AIDS patients are associated with coinfection with oncogenic viruses, such as Epstein-Barr virus, human herpesvirus 8, and human papillomavirus, with resulting malignancies occurring secondary to diminished immune surveillance against viruses and virus-infected tumor cells. Over 50% of AIDS lymphomas are associated with Epstein-Barr virus (EBV) and/or HHV8 infection. HHV8-associated diseases include Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). EBV is associated with several malignancies, including Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Coinfection with HIV and HPV is associated with an increased risk of various squamous cell carcinomas of epithelial tissues. HAART has significantly impacted the incidence, management, and prognosis of AIDS-related malignancies. In addition to changing the natural history of HIV infection in regard to incidence and survival, HAART has dramatically decreased the incidence of certain virally mediated HIV-associated malignancies such as KS and primary CNS lymphoma. The beneficial effects of HAART on these tumors are attributed to drug-mediated HIV suppression and immune reconstitution. However, HAART has had a less favorable impact on EBV- and HPV-related malignancies. This chapter presents an overview of HIV-associated malignancies mediated by HHV-8, EBV, and HPV, and reviews the effect of HAART on the epidemiology, presentation, treatment, and outcomes of these cancers.

Association of HIV status with infection by multiple HPV types

OBJECTIVES

To identify the clinical and demographic characteristics of HIV-positive and HIV-negative women infected by multiple HPV types.

METHODS

1399 women participated in the study (240 HIV-positive and 1159 HIV-negative women). Samples were provided for Pap tests and for HPV detection and typing by PCR. Data were collected on HPV infection, frequency of multiple infection, and HPV type distribution. Odds ratios were reported from logistic regression models.

RESULTS

Compared with HIV-negative women, HIV-positive women had higher frequencies of cervical abnormality (30% vs. 20.8%), higher HPV prevalence (68.3% vs. 51.3%) and were more commonly infected with multiple HPV types (78.7% vs. 44.3%). HPV-16 was the most common type detected in the study population, with other types showing variable associations with HIV status. Positive associations were observed between infection by multiple HPV types and HIV status, cervical abnormality and having had more than three pregnancies. The odds of multiple infection by HPV types were higher in HIV-positive women who used an intrauterine device, who had a history of abortions and who had HIV viral loads >100 000 copies/ml, whilst the odds were lower in women with >500 CD4 cells/mm³ .

CONCLUSIONS

HIV immunosuppression favours infection by multiple high-risk HPV types, mainly in women affected by low-grade squamous intraepithelial lesions. Antiretroviral therapy had no effect on infection by multiple HPV types. Risk factors related to progressive damage to the cervix were positively associated with infection by multiple HPV types in women living with HIV.

Screening for human papillomavirus, cervical cytological abnormalities and associated risk factors in HIV-positive and HIV-negative women in Rwanda

OBJECTIVES

Cervical cancer is the major cause of death from cancer in Africa. We wanted to assess the prevalence of human papillomavirus (HPV) infections and associated risk factors and to determine whether HPV testing could serve as a screening method for squamous intraepithelial lesions (SILs) in Rwanda. We also wanted to obtain a broader understanding of the underlying risk factors for the establishment of HPV infection in Rwanda.

METHODS

A total of 206 HIV-positive women, 172 HIV-negative women and 22 women with unknown HIV status were recruited at the University Teaching Hospitals of Kigali (UTHK) and of Butare (UTHB) in Rwanda. Participants underwent an interview, cervical sampling for a Thinprep Pap test and a screening test analysing 37 HPV strains.

RESULTS

Only 27% of HIV-positive women and 7% of HIV-negative women had been screened for cervical cancer before. HPV16 and HPV52 were the most common HPV strains. HIV-positive women were more commonly infected with high-risk (HR) HPV and multitype HPV than HIV-negative women. The sensitivity was 78% and the specificity 87% to detect high-grade SIL (HSIL) with HPV screening. Among HIV-negative women, being divorced was positively associated with HR-HPV infection, while hepatitis B, Trichomonas vaginalis infection and HR-HPV infection were factors positively associated with SILs. Ever having had gonorrhoea was positively associated with HR-HPV infection among HIV-positive women. HR-HPV infection and the number of live births were positively associated with SILs.

CONCLUSIONS

The currently used quadrivalent vaccine may be insufficient to give satisfactory HPV coverage in Rwanda. HPV Screening may be effective to identify women at risk of developing cervical cancer, particularly if provided to high-risk patients.

Human papillomavirus-associated cutaneous disease burden in human immunodeficiency virus (HIV)-positive patients: the role of human papillomavirus vaccination and a review of the literature

Human papillomavirus (HPV) infection is related to the development of cutaneous squamous cell carcinoma, oropharyngeal carcinoma, and anogenital malignancies. Patients infected with human immunodeficiency virus (HIV) have impaired cell-mediated immunity, placing them at risk for more prolonged infection with a greater likelihood of disease expression. This presents important implications for screening and treatment of HPV in the HIV patient population. The use of prophylactic vaccines directed against HPV has been a promising clinical development, though the immunogenicity of these vaccines in the immunocompromised host and in patients with previously established HPV infections has not been well established. In this review, we describe the pathogenesis and epidemiology of HPV-related cutaneous malignancies in patients with HIV. We outline the current guidelines and recent advances in the field of HPV vaccination. It is our hope that increasing awareness of the HPV-related HIV comorbidities will lead to developments in preventative medicine capable of reducing the burden of these diseases. We recognize the importance of prevention as a primary defense against disease and hope that this article organizes and disseminates recent findings in the field of HPV-associated comorbidities in the HIV population.

Multiple preinvasive and invasive HPV-related lesions of the anogenital tract in a female patient with HIV infection: A case report

RATIONALE

Patients with human immunodeficiency virus (HIV) infection have been shown to be at increased risk for high-risk human papillomavirus (HR-HPV) infection of the anogenital tract. Furthermore, in the last decades, the introduction of highly active antiretroviral therapy (HAART) has increased the longevity of these patients who now live long enough to develop HPV-related cancers; hence, the impact of HPV infection on HIV-positive patients is of increasing concern.

PATIENT CONCERNS

We reported the case of an HIV-positive female patient on HAART with a good virological and immunological response and with a long history of HPV-related intraepithelial and invasive lesions of the anogenital tract.

DIAGNOSES

From 1996 to 2016, this patient was diagnosed with a high grade cervical intraepithelial neoplasia; a HR-HPV positive inguinal lymph node metastasis from clinically undetectable primary squamous cell carcinoma; a HPV-related vulvar high-grade squamous intraepithelial lesion and an invasive squamous cell carcinoma of the anus.

INTERVENTIONS

All the intraepithelial and invasive lesions detected were properly treated, and subsequent follow up visits with gynecologic examination, anoscopy, pap smear and anal cytology were performed.

OUTCOMES

After a recurrence of the anal cancer and a subsequent salvage surgery with abdominoperineal resection, at the last available follow up visit no sign of disease recurrence was found.

LESSONS

This case stresses the importance of an accurate multidisciplinary follow-up in HIV-positive patients, including not only the routine medical, immunological, and virological evaluation, but also a periodical complete examination of the anogenital tract with cervicovaginal and anal cytology, colposcopy, high resolution anoscopy, and vulvar examination.

HIV Infection and Survival Among Women With Cervical Cancer

Purpose Cervical cancer is the leading cause of cancer death among the 20 million women with HIV worldwide. We sought to determine whether HIV infection affected survival in women with invasive cervical cancer. Patients and Methods We enrolled sequential patients with cervical cancer in Botswana from 2010 to 2015. Standard treatment included external beam radiation and brachytherapy with concurrent cisplatin chemotherapy. The effect of HIV on survival was estimated by using an inverse probability weighted marginal Cox model. Results A total of 348 women with cervical cancer were enrolled, including 231 (66.4%) with HIV and 96 (27.6%) without HIV. The majority (189 [81.8%]) of women with HIV received antiretroviral therapy before cancer diagnosis. The median CD4 cell count for women with HIV was 397 (interquartile range, 264 to 555). After a median follow-up of 19.7 months, 117 (50.7%) women with HIV and 40 (41.7%) without HIV died. One death was attributed to HIV and the remaining to cancer. Three-year survival for the women with HIV was 35% (95% CI, 27% to 44%) and 48% (95% CI, 35% to 60%) for those without HIV. In an adjusted analysis, HIV infection significantly increased the risk for death among all women (hazard ratio, 1.95; 95% CI, 1.20 to 3.17) and in the subset that received guideline-concordant curative treatment (hazard ratio, 2.63; 95% CI, 1.05 to 6.55). The adverse effect of HIV on survival was greater for women with a more-limited stage cancer ( P = .035), those treated with curative intent ( P = .003), and those with a lower CD4 cell count ( P = .036). Advanced stage and poor treatment completion contributed to high mortality overall. Conclusion In the context of good access to and use of antiretroviral treatment in Botswana, HIV infection significantly decreases cervical cancer survival.

Bonafide, type-specific human papillomavirus persistence among HIV-positive pregnant women: predictive value for cytological abnormalities, a longitudinal cohort study

This study investigated the rate of human papillomavirus (HPV) persistence, associated risk factors, and predictors of cytological alteration outcomes in a cohort of human immunodeficiency virus-infected pregnant women over an 18-month period. HPV was typed through L1 gene sequencing in cervical smears collected during gestation and at 12 months after delivery. Outcomes were defined as nonpersistence (clearance of the HPV in the 2nd sample), re-infection (detection of different types of HPV in the 2 samples), and type-specific HPV persistence (the same HPV type found in both samples). An unfavourable cytological outcome was considered when the second exam showed progression to squamous intraepithelial lesion or high squamous intraepithelial lesion. Ninety patients were studied. HPV DNA persistence occurred in 50% of the cases composed of type-specific persistence (30%) or re-infection (20%). A low CD4⁺T-cell count at entry was a risk factor for type-specific, re-infection, or HPV DNA persistence. The odds ratio (OR) was almost three times higher in the type-specific group when compared with the re-infection group (OR = 2.8; 95% confidence interval: 0.43-22.79). Our findings show that bonafide (type-specific) HPV persistence is a stronger predictor for the development of cytological abnormalities, highlighting the need for HPV typing as opposed to HPV DNA testing in the clinical setting.

Human papillomavirus in the HIV-infected host: epidemiology and pathogenesis in the antiretroviral era

Human papillomavirus (HPV) infection is associated with essentially all cervical cancers, 80-90 % of anal cancers, and a high proportion of oropharyngeal, vaginal, penile, and vulvar cancers. Malignancy is preceded by the development of precancerous lesions termed high-grade squamous intraepithelial lesions (HSIL). Men and women with human immunodeficiency virus (HIV) infection are at high risk of HPV-related malignancies. The incidence of anal cancer in particular has markedly risen during the antiretroviral era due to the increased longevity of patients with HIV and the absence of anal malignancy screening programs. HIV infection may facilitate initial HPV infection by disrupting epithelial cell tight junctions. Once infection is established, HIV may promote HSIL development via the up-regulation of HPV oncogene expression and impairment of the immune response needed to clear the lesion. HIV-infected women should be screened for cervical HSIL and cancer, and HIV-infected men and women should be considered for anal screening programs.

Immunologic Control of Mus musculus Papillomavirus Type 1

Persistent papillomas developed in ~10% of out-bred immune-competent SKH-1 mice following MusPV1 challenge of their tail, and in a similar fraction the papillomas were transient, suggesting potential as a model. However, papillomas only occurred in BALB/c or C57BL/6 mice depleted of T cells with anti-CD3 antibody, and they completely regressed within 8 weeks after depletion was stopped. Neither CD4+ nor CD8+ T cell depletion alone in BALB/c or C57BL/6 mice was sufficient to permit visible papilloma formation. However, low levels of MusPV1 were sporadically detected by either genomic DNA-specific PCR analysis of local skin swabs or in situ hybridization of the challenge site with an E6/E7 probe. After switching to CD3+ T cell depletion, papillomas appeared upon 14/15 of mice that had been CD4+ T cell depleted throughout the challenge phase, 1/15 of CD8+ T cell depleted mice, and none in mice without any prior T cell depletion. Both control animals and those depleted with CD8-specific antibody generated MusPV1 L1 capsid-specific antibodies, but not those depleted with CD4-specific antibody prior to T cell depletion with CD3 antibody. Thus, normal BALB/c or C57BL/6 mice eliminate the challenge dose, whereas infection is suppressed but not completely cleared if their CD4 or CD8 T cells are depleted, and recrudescence of MusPV1 is much greater in the former following treatment with CD3 antibody, possibly reflecting their failure to generate capsid antibody. Systemic vaccination of C57BL/6 mice with DNA vectors expressing MusPV1 E6 or E7 fused to calreticulin elicits potent CD8 T cell responses and these immunodominant CD8 T cell epitopes were mapped. Adoptive transfer of a MusPV1 E6-specific CD8+ T cell line controlled established MusPV1 infection and papilloma in RAG1-knockout mice. These findings suggest the potential of immunotherapy for HPV-related disease and the importance of host immunogenetics in the outcome of infection.

While most patients clear human papillomavirus (HPV) infection, some develop persistent papillomas, especially if immunocompromised. Likewise, we find a fraction of outbred SKH-1 mice challenged with Mus musculus papillomavirus type 1 (MusPV1/MmuPV1) develop persistent papillomas, whereas most SKH-1 mice, as seen for the inbred C57BL/6 and BALB/c strains, clear the infection. Viral clearance requires both CD4+ and CD8+ T cells, and depletion of either subset permits persistent but subclinical infection. In C57BL/6 mice, CD8+ T cell epitopes were mapped to MusPV1 E6 and E7; however the CD8+ T cell response to E6 dominated and correlated with spontaneous regression. A MusPV1 E6-specific CD8+ T cell line was developed by vaccination and culture in vitro, and its systemic administration once was sufficient to effect papilloma clearance in an immunodeficient mouse. Our observations in inbred and outbred mice challenged with MusPV1 suggest promise for immunotherapy to treat HPV-associated disease.

Outcomes Up to 12 Months After Treatment With Loop Electrosurgical Excision Procedure for Cervical Intraepithelial Neoplasia Among HIV-Infected Women

INTRODUCTION

HIV-infected women may have higher rates of recurrent cervical precancer after treatment. Knowledge about rates and predictors of recurrence could impact guidelines and program planning, especially in low-resource settings.

METHODS

In this prospective cohort study in Western Kenya, we followed HIV-infected women at 6 and 12 months after treatment for cervical intraepithelial neoplasia 2 or greater (CIN2+) after treatment with loop electrosurgical excision procedure (LEEP). All women underwent follow-up colposcopy with biopsy as indicated for the diagnosis of CIN2+. We calculated the incidence and predictors of primary disease recurrence after treatment.

RESULTS

Among the 284 women who underwent LEEP and had at least 1 follow-up visit, there were 37 (13%) cases of CIN2+ detected by 12-month follow-up. Four (10.8%) of the recurrences were invasive cancer, all stage IA1. The 6- and 12-month rates of recurrence were 13.7 and 12.8 cases per 100 person-years of follow-up, respectively. Antiretroviral therapy use did not significantly impact the rate of recurrence (hazard ratio: 1.24, 95% confidence interval: 0.59 to 2.79). The only significant predictor of recurrence in the multivariate analysis was CD4(+) nadir <200 cells per cubic millimeter (adjusted hazard ratio: 3.14, 95% confidence interval: 1.22 to 8.08).

DISCUSSION

The overall rate of treatment failure within a year of LEEP was low in this cohort of HIV-infected women. Among the women with recurrence, there was a significant amount of invasive cancer. The relatively high rate of cancer after treatment suggests that HIV-infected women merit continued close follow-up after treatment.

Pathology in Captive Wild Felids at German Zoological Gardens

This retrospective study provides an overview on spontaneous diseases occurring in 38 captive wild felids submitted for necropsy by German zoological gardens between 2004 and 2013. Species included 18 tigers, 8 leopards, 7 lions, 3 cheetahs and 2 cougars with an age ranging from 0.5 to 22 years. Renal lesions, predominantly tubular alterations (intra-tubular concrements, tubular degeneration, necrosis, intra-tubular cellular debris, proteinaceous casts, dilated tubuli) followed by interstitial (lympho-plasmacytic inflammation, fibrosis, metastatic-suppurative inflammation, eosinophilic inflammation) and glomerular lesions (glomerulonephritis, glomerulosclerosis, amyloidosis) were detected in 33 out of 38 animals (87%). Tumors were found in 19 of 38 felids (50%) with 12 animals showing more than one neoplasm. The tumor prevalence increased with age. Neoplasms originated from endocrine (11), genital (8), lympho-hematopoietic (5) and alimentary organs (4) as well as the mesothelium (3). Most common neoplasms comprised uterine/ovarian leiomyomas (5/2), thyroid adenomas/adenocarcinoma (5/1), pleural mesotheliomas (3), hemangiosarcomas (2) and glossal papillomas (2). Inflammatory changes were frequently encountered in the intestine and the lung. Two young animals displayed metastatic mineralization suggestive of a vitamin D- or calcium intoxication. One tiger exhibited degenerative white matter changes consistent with an entity termed large felid leukoencephalomyelopathy. Various hyperplastic, degenerative and inflammatory changes with minor clinical significance were found in several organs. Summarized, renal lesions followed by neoplastic changes as well as inflammatory changes in lung and gastrointestinal tract represent the most frequent findings in captive wild felids living in German zoological gardens.

Accumulation of invariant NKT cells with increased IFN-γ production in persistent high-risk HPV-infected high-grade cervical intraepithelial neoplasia

BACKGROUND

Persistent high-risk human papillomavirus (HR-HPV) infection has been implicated in the development of high-grade cervical intraepithelial neoplasia (CIN) and cervical cancer. Invariant natural killer T (iNKT) cells produce large amounts of cytokines to regulate immune responses. However, the role of iNKT cells in human persistent HPV-infected cervical tissues is unknown.

METHODS

In our study, 201 patients with diagnoses ranging from normal ectocervical tissue to CINIII from June 2010 to May 2012 were enrolled. HPV DNA and HPV types were detected using the hybrid capture-2 HPV DNA test. Flow cytometry was used to investigate iNKT and CD3+ T cell infiltration into cervical tissues. Real-time quantitative reverse transcription-polymerase chain reaction was used to study IFN-γ expression and immunohistochemistry was used to determine CD3+ T cell distribution.

RESULTS

A significant increase in iNKT cells was observed in HPV-positive cervical tissues (p < 0.05), especially in CINII-III (p < 0.01). IFN-γ expression was also increased in HPV-positive cervical tissues (p < 0.05). CD3+ T cells were detected among both epithelium and stromal layers in cervical tissues, and the percentage of CD3+ T cells in HPV-positive cervical tissues was similar to that in HPV-negative cervical tissues (p > 0.05).

CONCLUSIONS

The iNKT cell aggregation in cervical tissues during the progression from HPV infection to CIN indicates that iNKT cells might play an important role in suppressing immunity. IFN-γ expression could also be related to the HPV infection status. Preventing the accumulation or functioning of iNKT cells in cervical tissues may be a viable method to prevent the development of CIN.

VIRTUAL SLIDES

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2521874671514142.

Design aspects of a case-control clinical investigation of the effect of HIV on oral and gastrointestinal soluble innate factors and microbes

INTRODUCTION

The impaired host defense system in HIV infection impacts the oral and gastrointestinal microbiota and associated opportunistic infections. Antiretroviral treatment is predicted to partially restore host defenses and decrease the oral manifestation of HIV/AIDS. Well-designed longitudinal studies are needed to better understand the interactions of soluble host defense proteins with bacteria and virus in HIV/AIDS. "Crosstalk" was designed as a longitudinal study of host responses along the gastrointestinal (GI) tract and interactions between defense molecules and bacteria in HIV infection and subsequent therapy.

PURPOSE

The clinical core formed the infrastructure for the study of the interactions between the proteome, microbiome and innate immune system. The core recruited and retained study subjects, scheduled visits, obtained demographic and medical data, assessed oral health status, collected samples, and guided analysis of the hypotheses. This manuscript presents a well-designed clinical core that may serve as a model for studies that combine clinical and laboratory data.

METHODS

Crosstalk was a case-control longitudinal clinical study an initial planned enrollment of 170 subjects. HIV+ antiretroviral naïve subjects were followed for 9 visits over 96 weeks and HIV uninfected subjects for 3 visits over 24 weeks. Clinical prevalence of oral mucosal lesions, dental caries and periodontal disease were assessed.

RESULTS

During the study, 116 subjects (47 HIV+, 69 HIV-) were enrolled. Cohorts of HIV+ and HIV- were demographically similar except for a larger proportion of women in the HIV- group. The most prevalent oral mucosal lesions were oral candidiasis and hairy leukoplakia in the HIV+ group.

DISCUSSION

The clinical core was essential to enable the links between clinical and laboratory data. The study aims to determine specific differences between oral and GI tissues that account for unique patterns of opportunistic infections and to delineate the differences in their susceptibility to infection by HIV and their responses post-HAART.

Strain-specific properties and T cells regulate the susceptibility to papilloma induction by Mus musculus papillomavirus 1

The immunocytes that regulate papillomavirus infection and lesion development in humans and animals remain largely undefined. We found that immunocompetent mice with varying H-2 haplotypes displayed asymptomatic skin infection that produced L1 when challenged with 6×1010 MusPV1 virions, the recently identified domestic mouse papillomavirus (also designated "MmuPV1"), but were uniformly resistant to MusPV1-induced papillomatosis. Broad immunosuppression with cyclosporin A resulted in variable induction of papillomas after experimental infection with a similar dose, from robust in Cr:ORL SENCAR to none in C57BL/6 mice, with lesional outgrowth correlating with early viral gene expression and partly with reported strain-specific susceptibility to chemical carcinogens, but not with H-2 haplotype. Challenge with 1×1012 virions in the absence of immunosuppression induced small transient papillomas in Cr:ORL SENCAR but not in C57BL/6 mice. Antibody-induced depletion of CD3+ T cells permitted efficient virus replication and papilloma formation in both strains, providing experimental proof for the crucial role of T cells in controlling papillomavirus infection and associated disease. In Cr:ORL SENCAR mice, immunodepletion of either CD4+ or CD8+ T cells was sufficient for efficient infection and papillomatosis, although deletion of one subset did not inhibit the recruitment of the other subset to the infected epithelium. Thus, the functional cooperation of CD4+ and CD8+ T cells is required to protect this strain. In contrast, C57BL/6 mice required depletion of both CD4+ and CD8+ T cells for infection and papillomatosis, and separate CD4 knock-out and CD8 knock-out C57BL/6 were also resistant. Thus, in C57BL/6 mice, either CD4+ or CD8+ T cell-independent mechanisms exist that can protect this particular strain from MusPV1-associated disease. These findings may help to explain the diversity of pathological outcomes in immunocompetent humans after infection with a specific human papillomavirus genotype.

Immunity and squamous cell carcinoma of the anus: epidemiological, clinical and therapeutic aspects

Squamous cell carcinoma of the anus (SCCA) is a rare disease, but its incidence has been increasing dramatically since the 1970s. Men who have sex with men (MSM) and infection with human immunodeficiency virus (HIV) are the two main risk factors. Risk of developing SCCA is increased more than 100-fold in HIV-seropositive MSM. We review here how immunodeficiency could promote SCCA and how restoration of immunity since the advent of combined antiretroviral therapy can influence the natural history and incidence of SCCA. We also review the prognostic and therapeutic implications of immunosuppression in these patients. Finally, we show how, with anti-HPV vaccines, immunity is a target in the prevention of SCCA and could in the future be used in its treatment.

One lesion, one virus: individual components of high-grade anal intraepithelial neoplasia in HIV-positive men contain a single HPV type

BACKGROUND

High-grade anal intraepithelial neoplasia (AIN) is present in many human immunodeficiency virus (HIV)-positive men who have sex with men. The major etiologic factor is infection with an oncogenic human papillomavirus (HPV) genotype. We investigated whether individual components of high-grade AIN are caused by single HPV types.

METHODS

DNA was isolated from whole-tissue sections of 31 high-grade AIN that were recovered from 21 HIV-positive men who have sex with men. The SPF10 PCR/LiPA25 HPV genotyping system was used for DNA analysis. In whole-tissue sections with multiple HPV types, polymerase chain reaction was repeated in regions of AIN sampled by laser-capture microdissection. The results were compared with HPV types in anal swabs.

RESULTS

A single HPV type was observed in 15 (48%) of 31 whole-tissue sections. In an additional 14 whole-tissue sections, 1 HPV type was found in each lesion sample evaluated by laser-capture microdissection. Consequently, in 29 of 31 biopsy specimens (94%), a single HPV type was found in each lesional component studied. Two whole-tissue sections contained collision regions, each with 2 HPV types. HPV16 was presumed to be causative in 14 of 31 biopsy specimens (45%). More than half of the anal swabs did not contain all causative HPV types.

CONCLUSIONS

Individual components of high-grade AIN are caused by single HPV types (the so-called one lesion, one virus concept). HPV16 is causative in <50% of cases. Anal swabs are not useful for detecting lesion-specific HPV types.

Long-peptide therapeutic vaccination against CRPV-induced papillomas in HLA-A2.1 transgenic rabbits

Long peptide immunization is a promising strategy to clear established tumors. In the current study, we investigated the therapeutic effect of a naturally existing long peptide that contained two HLA-A2.1 restricted epitopes (CRPVE1/149-157 and CRPVE1/161-169) from cottontail rabbit papillomavirus (CRPV) E1 using our CRPV/HLA-A2.1 transgenic rabbit model. A universal Tetanus Toxin helper motif (TT helper) was tagged at either the N-terminus or the carboxyl-terminus of this long peptide and designated as TT-E1 peptide and E1 peptide-TT respectively. Four groups of HLA-A2.1 transgenic rabbits were infected with wild type CRPV DNA. Three weeks post-infection, the rabbits were immunized four times with TT-E1 peptide, E1peptide only, E1 peptide -TT or TT-control peptide with two-week intervals between immunizations. Tumor outgrowth was monitored and recorded weekly. After the third booster immunization, tumors on two of the four E1 peptide-TT immunized rabbits began to shrink. One animal from this group was free of tumors at the termination of the study. The mean papilloma size of E1 peptide-TT immunized rabbits was significantly smaller when compared with that of the three other groups (P<0.05, one way ANOVA analysis). It is interesting that E1 peptide-TT vaccination not only stimulated stronger T cell mediate immune responses but also stronger antibody generations. We conclude that the location of a TT helper motif tagged at the long peptide vaccine is critical for the outcome of therapeutic responses to persistent tumors in our HLA-A2.1 transgenic rabbit model.

The impact of human immunodeficiency virus infection on cervical preinvasive and invasive neoplasia in South Africa

OBJECTIVES

Sub-Saharan Africa is at the epicentre of the human immunodeficiency virus (HIV) epidemic and has the highest incidence of invasive cervical cancer (ICC) in the world. Access to highly active antiretroviral treatment (HAART) in South Africa is still limited and provided only to nonpregnant women with a CD4+ T-cell count <200 μg/L. We evaluated the relative distribution of cervical preinvasive and invasive neoplasia among HIV-infected (treated or not) and uninfected women in the Limpopo Province of South Africa.

METHODS

We compared the consecutive biopsy-diagnosed cervical pathology of 1,023 HIV-infected and 1,023 uninfected women. We investigated the influence of the CD4+ T-cell count and of HAART on the relative distribution of cervical pathology.

RESULTS

There was a significantly higher proportion of cervical intraepithelial neoplasia (CIN)1 (P = 0.012) and 2 (P = 0.01) but a lower proportion of ICC (P = 0.015) among HIV-infected women. Patients on HAART had less CIN1 (P = 0.018), 2 (P = 0.18) and ICC (P = 0.019) that their untreated counterparts. The mean CD4 count was similar regardless of cervical lesions and HAART or no treatment.

CONCLUSION

Our data support the concept that HIV-infected women exhibit a higher rate of high-grade preinvasive lesions than uninfected controls. However, they have a significantly lower rate of ICC as compared with uninfected counterparts. The inclusion of ICC among acquired immune deficiency syndrome-defining illnesses is questionable.

Risk of human papillomavirus-related cancers among kidney transplant recipients and patients receiving chronic dialysis--an observational cohort study

Background

Individuals with end-stage renal disease (ESRD) have excess risk of various cancer types. However, the total burden of human papillomavirus-related cancers remains unknown.

Methods

We performed a nationwide observational cohort study during 1994–2010.

For each person with ESRD, we sampled 19 population controls (without ESRD) matched on age, gender and municipality. Participants were followed until first diagnosis of human papillomavirus-related cancer, death, emigration, or 31 December 2010, whichever came first.

Human papillomavirus-related cancers were extracted from Danish medical administrative databases. We considered cancers of the cervix, vulva, vagina, penis, anus, and subsets of head and neck cancers as human papillomavirus-related. We calculated incidence rates of human papillomavirus-related cancer and used Poisson regression to identify risk factors for human papillomavirus-related cancer.

Results

Among 12,293 persons with ESRD and 229,524 population controls we identified 62 and 798 human papillomavirus-related cancers, respectively. Incidence rates of human papillomavirus-related- cancer were 102 per 100,000 person-years (95% confidence interval [CI]; 79.5-131) among persons with ESRD and 40.8 per 100,000 person-years (95% CI; 38.1-43.7) among population controls. ESRD patients had 4.54 (95% CI, 2.48-8.31) fold increased risk of anal cancer and 5.81 fold (95% CI; 3.36-10.1) increased risk of vulvovaginal cancer. Adjusted for age, comorbidity, and sex, ESRD patients had 2.41 (95% CI; 1.83-3.16) fold increased risk of any human papillomavirus-related cancer compared with population controls. Compared with dialysis patients renal transplant recipients had an age-adjusted non-significant 1.53 (95% CI, 0.91-2.58) fold higher risk of human papillomavirus-related cancer.

Conclusions

Persons with ESRD have excess risk of potentially vaccine-preventable human papillomavirus-related cancers.

Immunotherapy of human papilloma virus induced disease

Immunotherapy is the generic name for treatment modalities aiming to reinforce the immune system against diseases in which the immune system plays a role. The design of an optimal immunotherapeutic treatment against chronic viruses and associated diseases requires a detailed understanding of the interactions between the target virus and its host, in order to define the specific strategies that may have the best chance to deliver success at each stage of disease. Recently, a first series of successes was reported for the immunotherapy of Human Papilloma Virus (HPV)-induced premalignant diseases but there is definitely room for improvement. Here I discuss a number of topics that in my opinion require more study as the answers to these questions allows us to better understand the underlying mechanisms of disease and as such to tailor treatment.

Treatment failure in patients with HPV 16-induced vulvar intraepithelial neoplasia: understanding different clinical responses to immunotherapy

Failure of the immune system to launch a strong and effective immune response to high-risk HPV is related to viral persistence and the development of anogenital (pre)malignant lesions such as vulvar intraepithelial neoplasia (VIN). Different forms of immunotherapy, aimed at overcoming the inertia of the immune system, have been developed and met with clinical success. Unfortunately these, in principal successful, therapeutic approaches also fail to induce clinical responses in a substantial number of cases. In this review, the authors summarize the traits of the immune response to HPV in healthy individuals and in patients with HPV-induced neoplasia. The potential mechanisms involved in the escape of HPV-induced lesions from the immune system indicate gaps in our knowledge. Finally, the interaction between the immune system and VIN is discussed with a special focus on the different forms of immunotherapy applied to treat VIN and the potential causes of therapy failure. The authors conclude that there are a number of pre-existing conditions that determine the patients' responsiveness to immunotherapy. An immunotherapeutic strategy in which different aspects of immune failure are attacked by complementary approaches, will improve the clinical response rate.

Human papillomavirus immunogen that provides protective tumor immunity and induces tumor regression

Human papillomavirus (HPV) is associated with premalignant lesions such as high-grade cervical intraepithelial neoplasia (CIN-III) with potential progression to cervical carcinoma. There are now preventive vaccines against HPV. However, no effective therapeutic vaccine or immunological treatment exists for individuals already infected or for the 470,000 women that develop high-grade dysplasia, carcinoma in situ, and cervical cancer each year. More than half of these women die from cervical cancer. Relative non-immunogenicity of HPV infection is one of the main reasons for the difficulty in designing a comprehensive therapeutic vaccine against HPV-induced premalignant lesions and cervical carcinoma. HPV E6 and E7 proteins, the major HPV oncogenes, are highly immunogenic but fail to induce cross-reactive and protective immune responses against heterologous strains. We designed and synthesized a therapeutic peptide vaccine comprised of multivalent peptide mixtures called hypervariable epitope constructs (HECs) that represent the major epitope variants of the oncogenic E7 structural protein, and assessed their immunogenicity and in vivo efficacy in mice. Our results show that this peptide vaccine can induce strong, HPV-specific, T-helper cell and CTL responses. More significantly, we have demonstrated that the vaccine is efficacious as a therapeutic agent in a mouse HPV tumor model. Therefore, the HPV HEC vaccine approach described herein can potentially prevent progression of HPV-associated premalignant lesions, and may also be therapeutic against tumors associated with HPV.

Cervical cancer prevention in HIV-infected women using the "see and treat" approach in Botswana

BACKGROUND

Cervical cancer is a major public health problem in resource-limited settings, particularly among HIV-infected women. Given the challenges of cytology-based approaches, the efficiency of new screening programs need to be assessed.

SETTING

Community and hospital-based clinics in Gaborone, Botswana.

OBJECTIVE

To determine the feasibility and efficiency of the "see and treat" approach using visual inspection acetic acid (VIA) and enhanced digital imaging (EDI) for cervical cancer prevention in HIV-infected women.

METHODS

A 2-tier community-based cervical cancer prevention program was implemented. HIV-infected women were screened by nurses at the community using the VIA/EDI approach. Low-grade lesions were treated with cryotherapy on the same visit. Women with complex lesions were referred to our second tier specialized clinic for evaluation. Weekly quality control assessments were performed by a specialist in collaboration with the nurses on all pictures taken.

RESULTS

From March 2009 through January 2011, 2175 patients were screened for cervical cancer at our community-based clinic. Two hundred fifty-three patients (11.6%) were found to have low-grade lesions and received same-day cryotherapy. One thousand three hundred forty-seven (61.9%) women were considered to have a normal examination, and 575 (27.3%) were referred for further evaluation and treatment. Of the 1347 women initially considered to have normal exams, 267 (19.8%) were recalled based on weekly quality control assessments. Two hundred ten (78.6%) of the 267 recalled women, and 499 (86.8%) of the 575 referred women were seen at the referral clinic. Of these 709 women, 506 (71.4%) required additional treatment. Overall, 264 cervical intraepithelial neoplasia stage 2 or 3 were identified and treated, and 6 microinvasive cancers identified were referred for further management.

CONCLUSIONS

Our "see and treat" cervical cancer prevention program using the VIA/EDI approach is a feasible, high-output and high-efficiency program, worthy of considering as an additional cervical cancer screening method in Botswana, especially for women with limited access to the current cytology-based screening services.

Human papillomavirus, cancer and vaccination

PURPOSE OF REVIEW

HIV-positive men and women are at greater risk of human papillomavirus (HPV)-related cancers compared with the general population. This study describes recent findings in HPV-related cancers and precancerous lesions and discuss the potential benefit of recently developed prophylactic HPV vaccines.

RECENT FINDINGS

Despite improving access to antiretroviral therapy (ART), particularly in developing countries, the incidence of cervical cancer has not declined and the incidence of anal cancer is still rising in HIV-infected individuals. HIV appears to affect the history of HPV infection, and the distribution of genotypes detected in precancerous lesions in HIV-infected women is not similar to that of the general population. The use of the quadrivalent HPV vaccine has been shown to prevent cervical precursor lesions caused by the vaccine types in women in the general population. Safety and immunogenicity studies of the quadrivalent HPV vaccine in HIV-infected individuals are underway. Efficacy has to be proven in the context of both a different epidemiology of HPV infection and of immunosuppression.

SUMMARY

Recent data imply that the issue of HPV-related cancers will not decline in HIV-infected individuals. Therefore, efficacy studies of HPV vaccines are sorely needed in the setting of HIV.

Persistence of human papillomavirus infection: keys to malignant progression

Human papillomaviruses (HPVs) are the etiologic agents of cervical and other epithelial cancers. Persistence of infections by high-risk HPV types is the single greatest risk factor for malignant progression. Although prophylactic vaccines have been developed that target high-risk HPV types, there is a continuing need to understand better the virus-host interactions that underlie persistent benign infection and progression to cancer. In this review we summarize the molecular events that facilitate the differentiation-dependent HPV life cycle, how the life cycle is organized to facilitate virus persistence, and how the activities of HPV regulatory proteins result in malignancy.