Human papillomavirus-type distribution in South African women without cytological abnormalities: a peri-urban study

Phase I of the DiaVACCS screening trial: Study design, methods, population demographics and baseline results

Background. Human papillomavirus (HPV)-based primary screening guidelines are based on screening test performance and prevalence data generated in high-resource areas with low HIV infection rates. There is an urgent need for local data on infection and disease prevalence, as well as screening test performance, among both HIV-positive and HIV-negative South African (SA) women, in order to inform updated screening guidelines. Objectives. This study describes the baseline characteristics of participants in the cross-sectional phase of the multicentric DIAgnosis in Vaccine And Cervical Cancer Screen (DiaVACCS) screening trial. The objective was to determine the prevalence of positive screening and pre-invasive disease using different tests and strategies in the SA HIV-positive and HIV-negative population.Methods. A total of 1 104 women aged 25 - 65 years and eligible for screening were included, 465 HIV positive and 639 HIV negative. Visual inspection and molecular and cytological screening tests were done on self-sampled and healthcare worker-collected specimens. All participants who screened positive and 49.1% of those who screened negative were invited for colposcopy and biopsy, and those qualifying for treatment were recalled for large loop excision of the transformation zone as part of the trial. The worst histology result for each participant was used, and for untested women, multiple imputation was used to estimate verification bias- adjusted histology values. Results. Visual inspection was positive in 50.4% of HIV-positive v. 20.9% of HIV-negative women, cytology (atypical squamous cells of undetermined significance) in 39.9% v. 17.0%, and high-risk HPV DNA in 41.2% v. 19.6%. Overall, high-grade squamous intraepithelial lesion-positive cytology peaked in the age group 30 - 39 years at 16.7%. After adjustment for verification bias, histological diagnosis of cervical intraepithelial neoplasia (CIN)2+ was suspected in 44.7% v. 23.5% and CIN3+ in 23.3% v. 10.2% of HIV-positive and negative women, respectively. Invasive cancer was diagnosed in 15 women (1.95% of histological studies performed), and verification bias adjustment suggested 20 cases (1.8% of the study population). Conclusion. The baseline findings from the DiaVACCS trial confirm a high prevalence of HPV-related cervical pathology in the SA HIV-negative screening population, showing a clear need to reach these women with a screening programme. Among HIV-positive women, prevalence values were almost doubled. The prevalence of existing invasive cervical cancer was 1 - 2% of all women. Further analysis of the performance of single and multiple screening tests between the two subgroups will contribute to the choice of the most effective strategies to identify women at risk of developing invasive cancer.

Clinical implications of the interaction between HPV and HIV infections

HIV-related immunodeficiency has complex effects on female genital HPV, which include increased risks of infection, multiple types, persistence, reactivation and the risk to develop pre-invasive and invasive disease. Reconstitution of immunity with anti-viral drugs improves cellular immunity, but the risk of HPV-related malignancy remains higher than background incidences and presents at younger ages. Early initiation of antiretroviral therapy (ART) allows improved retention of immune memory through existing antibodies and T-cell clones and improves long-term outcomes. Suggestions of a higher risk to contract HIV if there is existing genital HPV infection are supported and explained by pathophysiological cervical changes, including inflammation. HIV-HPV interactions should influence public health decisions towards prioritising large-scale prepubertal HPV-vaccine roll-out, secondary cervical cancer prevention and early detection programmes for HIV-infected women and early initiation of ART. This chapter will also focus on special considerations for the management of women with co-infection with these two viruses and genital HPV-related diseases.

Persistent Low-Risk and High-Risk Human Papillomavirus Infections of the Uterine Cervix in HIV-Negative and HIV-Positive Women

BACKGROUND

The prevalence, persistence, and multiplicity of human papillomavirus (HPV) infection appears different comparing HIV-positive to HIV-negative women. In this study, we examined prevalent, persistent, and multiple low- and high-risk cervical HPV infections in HIV-negative and HIV-positive women.

METHODS

We studied 1,020 women involved in a study of HPV infection using SPF₂₅/LiPA₁₀. Two study visits were scheduled, at enrollment and 6 months afterward. At each study visit, research nurses used a cervical brush to collect samples of exfoliated cervical cells from the cervical os, from all the study participants. Exact logistic regression models were used to estimate associations between HIV and HPV infections.

RESULTS

The mean (SD) age of the study participants was 38 (8) years, 56% were HIV-negative and 44% were HIV-positive. Among HIV-negative women at baseline, single low-risk HPV (lrHPV) infections occurred in 12%; multiple lrHPV in 2%; single high-risk human papillomavirus (hrHPV) infections in 9%, and multiple hrHPV infections in 2%. Single lrHPV infections were persistent in 6%, but there was no persistent multiple lrHPV infections. Single hrHPV infections were persistent in 4% while multiple hrHPV infections were persistent in 0.3%. Among HIV-positive women at baseline, single lrHPV infections occurred in 19%, multiple lrHPV in 6%, single hrHPV infections in 17%, and multiple hrHPV infections occurred in 12%. Single lrHPV infections were persistent in 9%, multiple lrHPV infections in 0.6%, single hrHPV infections in 13%, while multiple hrHPV were persistent in 3%. Prevalent, persistent, and multiple infections were more common in HIV-positive women, compared to HIV-negative women. In multivariate models adjusted for age, marital status, socioeconomic status, age at sexual initiation, and douching, the odds ratios comparing HIV-positive to HIV-negative women, were 2.09 (95% CI 1.47-2.97, p < 0.001) for prevalent lrHPV, 1.26 (95% CI 0.66-2.40, p 0.47) for persistent lrHPV infections, 3.38 (95% CI 2.34-4.87, p < 0.001) for prevalent hrHPV, and 4.49 (95% CI 2.26-8.91, p < 0.001) for persistent hrHPV infections.

CONCLUSION

HIV infection was associated with higher prevalence of lrHPV, hrHPV, and persistence hrHPV infections, but not persistent lrHPV infections.

Laser micro-dissection and qPCR for identifying specific HPV types responsible for malignancy in penile lesions

The aim of the study was to identify specific human papillomavirus (HPV) type responsible for malignancy in penile tissue samples using laser micro-dissection and TaqMan quantitative real-time PCR (qPCR). The study was based on two pre-malignant and seven malignant penile tissue samples and laser micro-dissection was performed on all. Genotyping was performed on whole tissue sections and laser micro-dissection samples using qPCR. Two whole tissue section samples were HPV negative while seven were HPV positive. In four samples that were single HPV infections with whole tissue section PCR, identical HPV types were confirmed with laser micro-dissection PCR. Clearly confirming that the single HPV type detected is responsible for malignancy. In two samples that had multiple HPV infections with whole tissue section PCR, only one HPV type with the highest viral load was detected with laser micro-dissection PCR, suggesting that the HPV type with the highest viral load is most likely the cause of that particular lesion. HPV 11 and/or HPV 16 were the only types detected with laser micro-dissection PCR in these cases, compared to multiple HPV types (HPV 11, HPV 16, HPV 18, HPV 31, HPV 33, HPV 35, and HPV 39) initially detected with whole tissue section PCR. HPV 11 was associated with verrucous lesions while HPV 16 was associated with squamous cell carcinoma and PIN 3 lesions. This study confirms that laser micro-dissection and qPCR are essential tools in identifying the HPV types responsible for malignancy in penile lesions, particularly in samples with multiple infections.