Persistence of oncogenic and non-oncogenic human papillomavirus is associated with human immunodeficiency virus infection in Kenyan women

Association of plasma aflatoxin with persistent detection of oncogenic human papillomaviruses in cervical samples from Kenyan women enrolled in a longitudinal study

BACKGROUND

Cervical cancer is caused by oncogenic human papillomaviruses (HR-HPV) and is common among Kenyan women. Identification of factors that increase HR-HPV persistence is critically important. Kenyan women exposed to aflatoxin have an increased risk of HR-HPV detection in cervical specimens. This analysis was performed to examine associations between aflatoxin and HR-HPV persistence.

METHODS

Kenyan women were enrolled in a prospective study. The analytical cohort for this analysis included 67 HIV-uninfected women (mean age 34 years) who completed at least two of three annual study visits and had an available blood sample. Plasma aflatoxin was detected using ultra-high pressure liquid chromatography (UHPLC)-isotope dilution mass spectrometry. Annual cervical swabs were tested for HPV (Roche Linear Array). Ordinal logistic regression models were fitted to examine associations of aflatoxin and HPV persistence.

RESULTS

Aflatoxin was detected in 59.7% of women and was associated with higher risk of persistent detection of any HPV type (OR = 3.03, 95%CI = 1.08-8.55, P = 0.036), HR-HPV types (OR = 3.63, 95%CI = 1.30-10.13, P = 0.014), and HR-HPV types not included in the 9-valent HPV vaccine (OR = 4.46, 95%CI = 1.13-17.58, P = 0.032).

CONCLUSIONS

Aflatoxin detection was associated with increased risk of HR-HPV persistence in Kenyan women. Further studies, including mechanistic studies are needed to determine if aflatoxin synergistically interacts with HR-HPV to increase cervical cancer risk.

Effect of Human Immunodeficiency Virus Infection on Human Papillomavirus Clearance Among Women in Senegal, West Africa

BACKGROUND

Persistent infection with high-risk human papillomavirus (HPV) is associated with development of invasive cervical cancer.

METHODS

Longitudinal data was collected from 174 Senegalese women. We employed marginal Cox proportional hazards models to examine the effect of human immunodeficiency virus (HIV) status (HIV positive vs HIV negative) and HIV type (HIV-1 vs HIV-2 vs dual HIV-1/HIV-2) on clearance of type-specific HPV infection. Analyses were stratified by incident versus prevalent HPV infection.

RESULTS

Incident HPV infections in HIV-positive women were less likely to clear than those in HIV-negative women (adjusted hazard ratio [HR] = 0.60; 95% confidence interval [CI], .38-.94). Among HIV-positive women, HIV-2-infected women and HIV-1/2 dually infected women were more likely to clear HPV incident infections than HIV-1-infected women (HR = 1.66; 95% CI, .95-2.92 and HR = 2.17; 95% CI, 1.12-4.22, respectively). Incident HPV infections in HIV-positive women with CD4 cell count ≤500 cells/μL were less likely to clear than those in HIV-positive women with CD4 cell count >500 cells/μL (HR = 0.65; 95% CI, .42-1.01). No significant associations were observed for prevalent HPV infections.

CONCLUSIONS

HIV infection reduced the likelihood of clearance of incident HPV infection. Furthermore, among HIV-positive women, low CD4 cell count and dual HIV infection were each associated with reduced likelihood of clearance.

Association of Plasma Aflatoxin With Persistent Detection of Oncogenic Human Papillomaviruses in Cervical Samples From Kenyan Women Enrolled in a Longitudinal Study

Background Cervical cancer is common among Kenyan women and is caused by oncogenic human papillomaviruses (HR-HPV). Identification of factors that increase HR-HPV persistence is critically important. Kenyan women exposed to aflatoxin have an increased risk of cervical HR-HPV detection. This analysis was performed to examine associations between aflatoxin and HR-HPV persistence. Methods Kenyan women were enrolled in a prospective study. The analytical cohort for this analysis included 67 HIV-uninfected women (mean age 34 years) who completed at least two of three annual study visits and had an available blood sample. Plasma aflatoxin was detected using ultra-high pressure liquid chromatography (UHPLC)-isotope dilution mass spectrometry. Annual cervical swabs were tested for HPV (Roche Linear Array). Ordinal logistic regression models were fitted to examine associations of aflatoxin and HPV persistence. Results Aflatoxin was detected in 59.7% of women and was associated with higher risk of persistent detection of any HPV type (OR = 3.03, 95%CI = 1.08-8.55, P = 0.036), HR-HPV types (OR = 3.63, 95%CI = 1.30-10.13, P = 0.014), and HR-HPV types not included in the 9-valent HPV vaccine (OR = 4.46, 95%CI = 1.13-17.58, P = 0.032). Conclusions Aflatoxin detection was associated with increased risk of HR-HPV persistence in Kenyan women. Further studies are needed to determine if aflatoxin synergistically interacts with HR-HPV to increase cervical cancer risk.

The East Africa Consortium for human papillomavirus and cervical cancer in women living with HIV/AIDS

The East Africa Consortium was formed to study the epidemiology of human papillomavirus (HPV) infections and cervical cancer and the influence of human immunodeficiency virus (HIV) infection on HPV and cervical cancer, and to encourage collaborations between researchers in North America and East African countries. To date, studies have led to a better understanding of the influence of HIV infection on the detection and persistence of oncogenic HPV, the effects of dietary aflatoxin on the persistence of HPV, the benefits of antiretroviral therapy on HPV persistence, and the differences in HPV detections among HIV-infected and HIV-uninfected women undergoing treatment for cervical dysplasia by either cryotherapy or LEEP. It will now be determined how HPV testing fits into cervical cancer screening programs in Kenya and Uganda, how aflatoxin influences immunological control of HIV, how HPV alters certain genes involved in the growth of tumours in HIV-infected women. Although there have been challenges in performing this research, with time, this work should help to reduce the burden of cervical cancer and other cancers related to HIV infection in people living in sub-Saharan Africa, as well as optimized processes to better facilitate research as well as patient autonomy and safety. KEY MESSAGESThe East Africa Consortium was formed to study the epidemiology of human papillomavirus (HPV) infections and cervical cancer and the influence of human immunodeficiency virus (HIV) infection on HPV and cervical cancer.Collaborations have been established between researchers in North America and East African countries for these studies.Studies have led to a better understanding of the influence of HIV infection on the detection and persistence of oncogenic HPV, the effects of dietary aflatoxin on HPV detection, the benefits of antiretroviral therapy on HPV persistence, and the differences in HPV detections among HIV-infected and HIV-uninfected women undergoing treatment for cervical dysplasia by either cryotherapy or LEEP.

The role of infections in the causation of cancer in Kenya

Cancer constitutes a major health care burden in the world today with the situation worsening in resource poor settings as seen in most Sub-Saharan African (SSA) countries. Infections constitute by far the most common risk factors for cancer in SSA and being a typical country in this region, Kenya has experienced an upsurge in the incidence of various types of cancers in the last few decades. Although there is limited population-based data in Kenya of infections-associated cancers, this review provides an up-to-date literature-based discussion on infections-associated cancers, their pathogenesis, and preventive approaches in the country. The primary infectious agents identified are largely viral (human immunodeficiency virus, human papillomavirus (HPV), Kaposi's sarcoma-associated herpes virus, Epstein-Barr virus, hepatitis B virus (HBV), hepatitis C virus), and also bacterial: Helicobacter pylori and parasitic: Schistosomiasis haematobium. Cancers associated with infections in Kenya are varied but the predominant ones are Non-Hodgkin lymphoma, Kaposi's sarcoma, Hodgkin lymphoma, Burkitt's lymphoma, cervical, liver, and gastric cancers. The mechanisms of infections-induced carcinogenesis are varied but they mainly seem to stem from disruption of signaling, chronic inflammation, and immunosuppression. Based on our findings, actionable cancer-preventive measures that are economically feasible and aligned with existing infrastructure in Kenya include screening and treatment of infections, implementation of cancer awareness and screening, and vaccination against infections primarily HBV and HPV. The development of vaccines against other infectious agents associated with causation of cancer remains also as an important goal in cancer prevention.

Longer duration of anti-retroviral therapy is associated with decreased risk of human papillomaviruses detection in Kenyan women living with HIV

OBJECTIVE

A longitudinal study was conducted among women living with HIV in Kenya to determine if duration of anti-retroviral (ART) usage altered detection and persistence of oncogenic (high-risk) human papillomaviruses (HR-HPV).

METHODS

Women living with HIV without cervical dysplasia were enrolled at a cervical cancer screening clinic. Three cervical swabs, HIV viral loads, and CD4 cell counts were obtained at enrollment and at two annual visits. HPV genotyping was performed on swabs (Roche Linear Array). Linear regression models assessed effects of ART duration on HR-HPV detection and persistence.

RESULTS

Seventy-seven women, median age 38 years, completed three study visits and were included in the analysis. The mean time from HIV diagnosis to enrollment was 9.6 years (SD 3.9 years). The mean ART duration was 6.2 years (SD 3.1 years). Most women had undetectable HIV viral loads and CD4 cell counts above 500 cells/L. Each additional year of ART use reduced the likelihood of detection of HR-HPV by 10-15% and persistent detection of A9 HR-HPV by 20%.

CONCLUSION

Among Kenyan women living with HIV, longer duration of ART use was associated with significantly reduced risk of all detection and persistent detection of HR-HPV.

Worldwide genetic variations in high-risk human papillomaviruses capsid L1 gene and their impact on vaccine efficiency

BACKGROUND

Human papillomavirus is the most common sexually transmitted infection. It is associated with different cancers, mainly cervical cancer, which remains the fourth most frequent cancer among women worldwide; it is also related to anogenital (anus, vulvar, vagina, and penis) and oropharyngeal cancers. Vaccination against HPV infection is the major way of prevention, and it has demonstrated impressive efficacy in reducing cervical cancer incidence. Nowadays, all the licensed HPV recombinant vaccines were designed based on HPV major capsid L1 protein. However, some variations in the HPV L1 gene sequence may induce structural changes within the L1 protein, which may alter the affinity and interaction of monoclonal antibodies (MAbs) with L1 protein epitopes, and influence host immune response and recognition. Hence, the importance of accuracy in delineating epitopes relevant to vaccine design and defining genetic variations within antigenic regions in the L1 gene to predict its impact on prophylactic vaccine efficiency. The present review reports the sequence variations in HR-HPV L1 gene isolates from different countries around the world, which may help to understand the effect of HPV L1 gene variations on vaccine efficiency.

METHODS

Research studies were retrieved from PubMed, Google Scholar, Science direct, and the National Center for Biotechnology Information (NCBI) database. A total of 31 articles describing genetic variations within the major capsid L1 gene and conducted in Africa, Europe, America and Asia were found. Only 26 studies conducted on HPV16, 18, 31, 33, 58, 45 and 52 which are the targets of HPV prophylactic vaccines, and which reported genetic variations within the L1 gene, were selected and evaluated in this review.

FINDINGS

We found a total of 87, 49, 11, 7, 22, 3, and 17 non-synonymous single nucleotide polymorphisms (SNPs) within HPV16, HPV18, HPV31, HPV58, HPV45, and HPV52 L1 gene, respectively. Four mutations were frequently observed in HPV16 L1 sequences: T353P in the HI loop, H228D in the EF loop, T266A in the FG loop, and T292A in the FG loop. Two mutations in HPV58 L1 sequences: T375N in the HI loop and L150F in the DE loop. Three mutations in HPV33 L1 sequences: T56N in the BC loop, G133S in the DE loop, T266K in the FG loop. Other mutations were found in HPV18, HPV45, and HPV52 L1 sequences. Some were found in different countries, and others were specific to a given population. Furthermore, some variations were located on peptide binding epitopes and lead to a modification of epitopes, which may influence MAbs interactions. Others need further investigations due to the lack of studies.

CONCLUSION

This study investigated the major capsid L1 genetic diversity of HPV16, 18, 31, 33, 58, 45, and 52 circulating in different populations around the world. Further investigations should be conducted to confirm their effect on immunogenicity and prophylactic vaccine efficiency.