High-risk human papillomavirus diversity among indigenous women of western Botswana with normal cervical cytology and dysplasia.

BACKGROUND: Cervical cancer remains a public health problem despite heavy global investment in health systems especially in low-and-middle-income countries (LMIC). Prophylactic vaccines against the most commonly detected human papillomavirus (HPV) types in cervical cancers are available and decisions on the selection of vaccine design depends on the prevalence of high-risk (hr) HPV genotypes for a particular region. In 2015, Botswana adopted the use of a quadrivalent HPV vaccine as a primary prevention strategy. Secondary prevention includes cervical smear screening whose uptake remains notably low among indigenous and marginalized communities despite efforts to improve access. AIM: To determine the prevalence of hrHPV genotypes and cervical lesions' burden in women from the indigenous and marginalized communities of Botswana. METHODS: This prospective survey enrolled 171 non-HPV vaccinated women aged 21 years and older. Face-to-face interviews, Pap smear screening, hr-HPV and Human Immuno-deficiency virus (HIV) testing were carried out. Conventional Papanicolau smears were analyzed and cervical brushes were preserved for hrHPV testing using the Ampfire Multiplex HR-HPV protocol which detects the following genotypes: HPV 16, 18, 31, 35, 39, 45, 51, 52, 53, 56, 58, 59 and 68. RESULTS: In this study, 168/171 (98.6%) of the women consented to HIV testing; 53/171 (31%) were living with HIV and self-reported enrolment on antiretroviral therapy. Among the women examined, 23/171 (13.5%) had cervical dysplasia with most presenting with Atypical Squamous Cells of Undetermined Significance 8/23 (35%), Low-Grade Squamous Intraepithelial Lesions 8/23 (35%), Atypical Squamous Cells-High Grade 4/23 (17%), Atypical Endocervical Cells 2/23 (9%) and Atypical Endocervical Cell favoring neoplasia 1/23(4%). However, no High-Grade Squamous Intraepithelial Lesions (HSIL) or squamous cell carcinoma (SCC) were detected. Overall hrHPV prevalence in this study was at 56/171 (32.7%). The most commonly detected hrHPV genotypes in women with cervical dysplasia were HPV39 (6.25%), HPV51 (14.5%), HPV52 (12.5%) and HPV56 (4%). Notably, HPV 16 and 18 were not found in women with cervical dysplasia. CONCLUSIONS: Our study provides valuable insights into the prevalence and distribution of hrHPV genotypes in indigenous and marginalized communities in Botswana, and the need for further investigation of their potential role in cervical carcinogenesis in this population. These results may also serve as baseline data to facilitate future evaluation of the HPV vaccine needs.

Genetic diversity in L1 ORF of human papillomavirus in women with cervical cancer with and without human immunodeficiency virus in Botswana and Kenya.

BACKGROUND: The variation of human papillomavirus (HPV) genotypes shapes the risks of cervical cancer and these variations are not well defined in Africa. Nucleotide changes within the L1 gene, nucleotide variability, and phylogeny were explored in relation to HIV in samples from Botswana and Kenya. METHODS: A total of 98 HPV-positive cervical samples were sequenced to identify different HPV variants. Phylogenetic inferences were used to determine HPV genotypes and investigate the clustering of sequences between women living with HIV (WLWHIV) and -women not living with HIV (WNLWHIV). RESULTS: Out of 98 generated sequences, 83.7% (82/98) participants had high-risk (HR) HPV genotypes while 16.3% (16/98) had low-risk (LR) HPV genotypes. Among participants with HR-HPV genotypes, 47.6% (39/82) were coinfected with HIV. The prevalence of HR-HPV genotypes was statistically higher in the Botswana population compared to Kenya (p-value < 0.001). Multiple amino acid mutations were identified in both countries. Genetic diversity differed considerably among WLWHIV and WNLWHIV. The mean pairwise distances between HPV-16 between HIV and HIV/HPV as well as for HPV-18 were statistically significant. Six (6) new deleterious mutations were identified in the HPV genotypes based on the sequencing of the L1 region, HPV-16 (L441P, S343P), HPV-18 (S424P), HPV-45 (Q366H, Y365F), and HPV-84 (F458L). The majority of the patients with these mutations were co-infected with HIV. CONCLUSIONS: Genomic diversity and different genomic variants of HPV sequences were demonstrated. Candidate novel mutations within the L1 gene were identified in both countries which can be further investigated using functional assays.

Outcomes of Reflex Cryptococcal Antigen (CrAg) Screening in Human Immunodeficiency Virus (HIV)-Positive Patients With CD4 Counts of 100-200 Cells/µL in Botswana.

Increasing the CD4-count threshold for cryptococcal antigen (CrAg) screening from ≤100 to ≤200 cells/µL resulted in a 3-fold increase in numbers screened. CrAg-prevalence was 3.5% at CD4 101-200 and 6.2% ≤100 cells/µL. Six-month mortality was 21.4% (9/42) in CrAg-positive CD4 ≤100 cells/µL and 3.2% (1/31) in CrAg-positive CD4 101-200 cells/µL.

Human papillomavirus genotypes in women with invasive cervical cancer with and without human immunodeficiency virus infection in Botswana.

Cervical cancer remains a significant cause of morbidity and mortality in women worldwide and is the leading cause of cancer-related death in Botswana. It is well established that women with HIV have a higher risk of persistent HPV infection leading to cervical cancer. We assessed HPV prevalence and genotype distribution in 126 tissue specimens from confirmed invasive cervical cancer cases using Abbott real-time PCR assay. Overall, 88 (69.8%) women were HIV-infected. Fifty-seven (64.8%) of the HIV-infected women had a baseline CD4+ count ≥350 cells/µl, and 82 (93.2%) were on antiretroviral therapy at the time of cervical cancer diagnosis. The median age of HIV-infected patients was significantly younger than that of HIV-uninfected patients (p < 0.001). HPV DNA was detected in all of 126 (100%) of tissues analyzed in our study. The HPV genotypes identified included the HPV-16 (75.4%), HPV-18 (28.6%) and other high-risk (hr) HPV genotypes (16.7%). HIV infection was positively associated with the presence of the HPV-16 genotype (p = 0.036), but not with HPV-18 or with other high-risk (hr)-HPV genotypes. Thirty-three percent of the patients had multiple hr-HPV genotypes, with higher rates in HIV-infected women. These results highlight the importance and potential impact of large-scale HPV vaccination programs covering HPV-16 and HPV-18 genotypes in countries like Botswana with high burden of HIV infection.

Diagnostic Accuracy of the Biosynex CryptoPS Cryptococcal Antigen Semiquantitative Lateral Flow Assay in Patients with Advanced HIV Disease.

High cryptococcal antigen (CrAg) titers in blood are associated with subclinical meningitis and mortality in CrAg-positive individuals with advanced HIV disease (AHD). We evaluated a novel semiquantitative lateral flow assay (LFA), CryptoPS, that may be able to identify individuals with high CrAg titers in a cohort of AHD patients undergoing CrAg screening. In a prospective cohort of patients with AHD (CD4 cell count, ≤200/µl) receiving CD4 count testing, whole blood was tested for CrAg by CryptoPS and the IMMY LFA; the two assays were conducted by two different operators, each blind to the results of the other assay. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CryptoPS were assessed against the IMMY LFA as a reference. CryptoPS low-titer (T1 band) and high-titer (T2 band) results were compared with IMMY LFA titers obtained through serial dilution. A total of 916 specimens were tested. The sensitivity of the CryptoPS assay was 61.0% (25/41) (95% confidence interval [95% CI], 44.5 to 75.8%), its specificity was 96.6% (845/875) (95% CI, 95.1 to 97.7%), its PPV was 45.5% (95% CI, 32.0 to 59.4%), and its NPV was 98.1% (95% CI, 97.0 to 98.9%). All (16/16) CryptoPS false-negative results were obtained for samples with IMMY titers of ≤1:160. Of 29 patients (30 specimens) who tested positive by CryptoPS but negative by the IMMY LFA, none developed cryptococcal meningitis over 3 months of follow-up without fluconazole. Median CrAg titers were 1:20 (interquartile range [IQR], 0 to 1:160) in CryptoPS T1-positive samples and 1:2,560 (IQR, 1:1,280 to 1:10,240) in T2-positive samples. We conclude that the diagnostic accuracy of the CryptoPS assay was suboptimal in the context of CrAg screening, with poor sensitivity at low CrAg titers. However, the CryptoPS assay reliably detected individuals with high titers, which are associated with poor outcomes.

Evaluation of a Novel Semiquantitative Cryptococcal Antigen Lateral Flow Assay in Patients with Advanced HIV Disease.

Higher cryptococcal antigen (CrAg) titers are strongly associated with mortality risk in individuals with HIV-associated cryptococcal disease. Rapid tests to quantify CrAg levels may provide important prognostic information and enable treatment stratification. We performed a laboratory-based validation of the IMMY semiquantitative cryptococcal antigen (CrAgSQ) lateral flow assay (LFA) against the current gold standard CrAg tests. We assessed the diagnostic accuracy of the CrAgSQ in HIV-positive individuals undergoing CrAg screening, determined the relationship between CrAgSQ scores and dilutional CrAg titers, assessed interrater reliability, and determined the clinical correlates of CrAgSQ scores. A total of 872 plasma samples were tested using both the CrAgSQ LFA and the conventional IMMY CrAg LFA, of which 692 were sequential samples from HIV-positive individuals undergoing CrAg screening and an additional 180 were known CrAg-positive plasma samples archived from prior studies. Interrater agreement in CrAgSQ reading was excellent (98.17% agreement, Cohen's kappa 0.962, P < 0.001). Using the IMMY CrAg LFA as a reference standard, CrAgSQ was 93.0% sensitive (95% confidence interval [CI] 80.9% to 98.5%) and 93.8% specific (95% CI, 91.7% to 95.6%). After reclassification of discordant results using CrAg enzyme immunoassay testing, the sensitivity was 98.1% (95% CI, 90.1% to 100%) and specificity 95.8% (95% CI, 93.9% to 97.2%). The median CrAg titers for semiquantitative score categories (1+ to 4+) were 1:10 (interquartile range [IQR], 1:5 to 1:20) in the CrAgSQ 1+ category, 1:40 (IQR, 1:20 to 1:80) in the CrAgSQ 2+ category, 1:640 (IQR, 1:160 to 1:2,560) in the CrAgSQ 3+ category, and 1:5,120 (IQR, 1:2,560 to 1:30,720) in the CrAgSQ 4+ category. Increasing CrAgSQ scores were strongly associated with 10-week mortality. The IMMY CrAgSQ test had high sensitivity and specificity compared to the results for the IMMY CrAg LFA and provided CrAg scores that were associated with both conventional CrAg titers and clinical outcomes.

Preliminary survey on Anopheles species distribution in Botswana shows the presence of Anopheles gambiae and Anopheles funestus complexes.

BACKGROUND: Botswana is one of the four front line malaria elimination countries in Southern Africa, with malaria control activities that include routine vector control. Past and recent studies have shown that Anopheles arabiensis is the only known vector of Plasmodium parasites in the country. This report presents a preliminary evaluation on Anopheles species composition in seven districts of Botswana with some inferences on their vectorial role. RESULTS: Overall, 404 Anopheles mosquito females were collected, of which 196 were larvae collected from several breeding sites, and 208 were adults obtained from indoor pyrethrum spray catches (PSC). Anopheles arabiensis (58.9%) accounted for the highest relative frequency in 5 out of 7 districts sampled. The other species collected, among those identified, were barely represented: Anopheles longipalpis type C (16.3%), Anopheles parensis (8.9%), Anopheles quadriannulatus (5.4%), and Anopheles leesoni (0.2%). PCR test for human ß-globin on mosquitoes collected by PSC showed that An. arabiensis and An. parensis had bitten human hosts. Moreover, An. arabiensis showed a non-negligible Plasmodium falciparum infection rate in two sites (3.0% and 2.5% in Chobe and Kweneng West districts, respectively). CONCLUSIONS: This work provides first time evidence of Anopheles diversity in several areas of Botswana. Anopheles arabiensis is confirmed to be widespread in all the sampled districts and to be vector of P. falciparum. Moreover, the presence of Anopheles funestus group in Botswana has been assessed. Further research, entomological surveillance activities and possibly vector control programmes need to be better developed and implemented as well as targeting outdoors resting vectors.

Triage of HPV positivity in a high HIV prevalence setting: A prospective cohort study comparing visual triage methods and HPV genotype restriction in Botswana.

OBJECTIVE: Guidelines for effective triage following positive primary high-risk human papillomavirus (HPV) screening in low- and middle-income countries with high human immunodeficiency virus (HIV)-prevalence have not previously been established. In the present study, we evaluated the performance of three triage methods for positive HPV results in women living with HIV (WLHIV) and without HIV in Botswana. METHODS: We conducted baseline enrollment of a prospective cohort study from February 2021 to August 2022 in South-East District, Botswana. Non-pregnant women aged 25 or older with an intact cervix and no prior diagnosis of cervical cancer were systematically consented for enrollment, with enrichment of the cohort for WLHIV. Those who consented completed a questionnaire and then collected vaginal self-samples for HPV testing. Primary HPV testing for 15 individual genotypes was conducted using Atila AmpFire® HPV assay. Those with positive HPV results returned for a triage visit where all underwent visual inspection with acetic acid (VIA), colposcopy, and biopsy. Triage strategies with VIA, colposcopy and 8-type HPV genotype restriction (16/18/31/33/35/45/52/58), separately and in combination, were compared using histopathology as the gold standard in diagnosing cervical intraepithelial neoplasia (CIN) 2 or worse (CIN2+). RESULTS: Among 2969 women enrolled, 1480 (50%) tested HPV positive. The cohort included 1478 (50%) WLHIV; 99% were virologically suppressed after a mean of 8 years on antiretroviral therapy. In total, 1269 (86%) women had histopathology data for analysis. Among WLHIV who tested positive for HPV, 131 (19%) of 688 had CIN2+ compared with 71 (12%) of 581 in women without HIV. Screening by 8-type HPV genotype restriction was more sensitive as triage to detect CIN2+ in WLHIV 87.79% (95% CI: 80.92-92.85) and women without HIV 85.92% (95% CI: 75.62-93.03) when compared with VIA (WLHIV 62.31% [95% CI: 53.39-70.65], women without HIV 44.29% [95% CI: 32.41-56.66]) and colposcopy (WLHIV 70.77% [95% CI: 62.15-78.41], women without HIV 45.71% [95% CI: 33.74-58.06]). However, 8-type HPV genotype restriction had low specificity in WLHIV of 30.88% (95% CI: 27.06-34.90) and women without HIV 37.06% (95% CI: 32.85-41.41). These results were similar when CIN3+ was used as the outcome. When combining 8-type HPV genotype restriction with VIA as the triage strategy, there was improved specificity to detect CIN2+ in WLHIV of 81.65% (95% CI: 78.18-84.79) but dramatically reduced sensitivity of 56.15% (95% CI: 47.18-64.84). CONCLUSIONS: Eight-type HPV genotype restriction is a promising component of effective triage for HPV positivity. However, novel triage strategies in LMICs with high HIV prevalence may be needed to avoid the trade-off between sensitivity and specificity with currently available options. CLINICAL TRIALS REGISTRATION: This study is registered on Clinicaltrials.gov no. NCT04242823, https://clinicaltrials.gov/ct2/show/NCT04242823.

Cervical cancer screening in HIV-endemic countries: An urgent call for guideline change.

Women living with HIV (WLWH) are at an increased risk of developing HPV-related high grade cervical dysplasia and cervical cancer. Prior World Health Organization (WHO) screening guidelines recommended starting screening at age 30. We assessed characteristics of women diagnosed with cervical cancer to further inform and refine screening guidelines. We prospectively enrolled women diagnosed with cervical cancer from January 2015 to March 2020 at two tertiary hospitals in Gaborone, Botswana. We performed chi-square and ANOVA analyses to evaluate the association between age upon diagnosis and HIV status, CD4 count, viral load, and other sociodemographic and clinical factors. Data were available for 1130 women who were diagnosed with cervical cancer and 69.3% were WLWH. The median age overall was 47.9 (IQR 41.2-59.1), 44.6 IQR: 39.8 - 50.9) among WLWH, and 61.2 (IQR 48.6-69.3) among women living without HIV. There were 1.3% of women aged <30 years old, 19.1% were 30-39 and 37.2% were 40-49. Overall, 20.4% (n = 231) of cancers were in women <40 years. Age of cervical cancer diagnosis is younger in countries with higher HIV prevalence, like Botswana. Approximately 20% of the patients presented with cancer at <40 years of age and would have likely benefited from screening 10 years prior to cancer diagnosis to provide an opportunity for detection and treatment of pre-invasive disease.

Comparison of the AmpFire Multiplex HPV Assay to the Xpert HPV Assay for detection of human papillomavirus and cervical disease in women with human immunodeficiency virus: A pragmatic performance evaluation.

Background: Low- and middle-income countries (LMICs) account for nearly 85% of the global cervical cancer burden, yet have the least access to high-performance screening. International guidelines recommend human papillomavirus testing (HPV) as primary screening, yet implementation is inhibited by the cost of HPV testing.Atila AmpFire HPV Assay (AmpFire) is both affordable and easy to use, and offers individual genotyping. The objective of this study was to compare the performance of the AmpFire HPV assay to the Xpert HPV assay in detection of both HPV and clinically significant cervical disease. Methods: We utilized stored cervical specimens from a prospective cohortstudy of women living with human immunodeficiency virus (HIV) in Botswana conducted from May to July 2018. Positive and negative percent agreement was calculated for the AmpFire and Xpert assays, as was detection of high-grade cervical dysplasia. Results : 63 stored cervical specimens haddetectable DNA after thawing and were included in the analysis. The positive percent agreement was 91.2% (95%CI: 76.3-98.1) and negative percent agreement was 79.3% (95% CI: 60.3-92.0). Six cases positive by AmpFire but negative by Xpert were HPV genotypes 35, 52 (n=2), 58, 68, and co-infection with HPV 45 and 68. Both Xpert and AmpFire assays detected HPV in all 10 samples of women who had high-grade cervical dysplasia. Conclusions : The AmpFire HPV assay demonstrated excellent analytic performance in both detection of HPV and clinically significant cervical disease. AmpFire HPV is a promising option to increase access to affordable, type-specific HPV screening for cervical cancer in LMICs.

No Difference in the Prevalence of HIV-1 gag Cytotoxic T-Lymphocyte-Associated Escape Mutations in Viral Sequences from Early and Late Parts of the HIV-1 Subtype C Pandemic in Botswana.

HIV is known to accumulate escape mutations in the gag gene in response to the immune response from cytotoxic T lymphocytes (CTLs). These mutations can occur within an individual as well as at a population level. The population of Botswana exhibits a high prevalence of HLA*B57 and HLA*B58, which are associated with effective immune control of HIV. In this retrospective cross-sectional investigation, HIV-1 gag gene sequences were analyzed from recently infected participants across two time periods which were 10 years apart: the early time point (ETP) and late time point (LTP). The prevalence of CTL escape mutations was relatively similar between the two time points-ETP (10.6%) and LTP (9.7%). The P17 protein had the most mutations (9.4%) out of the 36 mutations that were identified. Three mutations (A83T, K18R, Y79H) in P17 and T190A in P24 were unique to the ETP sequences at a prevalence of 2.4%, 4.9%, 7.3%, and 5%, respectively. Mutations unique to the LTP sequences were all in the P24 protein, including T190V (3%), E177D (6%), R264K (3%), G248D (1%), and M228L (11%). Mutation K331R was statistically higher in the ETP (10%) compared to the LTP (1%) sequences (p < 0.01), while H219Q was higher in the LTP (21%) compared to the ETP (5%) (p < 0.01). Phylogenetically, the gag sequences clustered dependently on the time points. We observed a slower adaptation of HIV-1C to CTL immune pressure at a population level in Botswana. These insights into the genetic diversity and sequence clustering of HIV-1C can aid in the design of future vaccine strategies.

Comparison of the AmpFire® Multiplex HPV Assay to the Xpert® HPV Assay for detection of human papillomavirus and cervical disease in women with human immunodeficiency virus: a pragmatic performance evaluation.

BACKGROUND: Low- and middle-income countries (LMICs) account for nearly 85% of the global cervical cancer burden, yet have the least access to high-performance screening. International guidelines recommend human papillomavirus testing (HPV) as primary screening, yet implementation is inhibited by the cost of HPV testing. Atila AmpFire® HPV Assay (AmpFire) is both affordable and easy to use, and offers individual genotyping. The objective of this study was to compare the performance of the AmpFire HPV assay to the Xpert® HPV assay in detection of both HPV and clinically significant cervical disease. METHODS: We utilized stored cervical specimens from a prospective cohort study of women living with human immunodeficiency virus (HIV) in Botswana conducted from May to July 2018. Positive and negative percent agreement was calculated for the AmpFire and Xpert assays, as was detection of high-grade cervical dysplasia. RESULTS: 63 stored cervical specimens had detectable DNA after thawing and were included in the analysis. The positive percent agreement was 91.2% (95%CI 76.3-98.1) and negative percent agreement was 79.3% (95% CI 60.3-92.0). Six cases positive by AmpFire but negative by Xpert were HPV genotypes 35, 52 (n = 2), 58, 68, and co-infection with HPV 45 and 68. Both Xpert and AmpFire assays detected HPV in all 10 samples of women who had high-grade cervical dysplasia. CONCLUSIONS: The AmpFire HPV assay demonstrated excellent analytic performance in both detection of HPV and clinically significant cervical disease. AmpFire HPV is a promising option to increase access to affordable, type-specific HPV screening for cervical cancer in LMICs.

Bibliometric analysis of cancer research outputs in Botswana between 2009 and 2021.

INTRODUCTION: Cancer research is critical for cancer control policies; however, the state of cancer research activities in Botswana is largely unknown. The goal of this review was to describe trends and patterns of cancer research outputs in Botswana. METHODS: PubMed, Web of Science, EBSCOhost, African Journals Online, and African Index Medicus databases were systematically searched for peer-reviewed, primary cancer-related research articles published on the Botswana population or by Botswana institutions between January 2009 and June 2021. RESULTS: Of the 86 publications included, 39 (45 %) were about cervical cancer, followed by breast cancer (10 %) and Kaposi sarcoma (7 %). The remainder (27 %) were not focused on any specific cancer type. The research activities were skewed towards three main areas of scientific interest: early detection, diagnosis, and prognosis; cancer control, survivorship, and outcomes; and treatment. Botswana was represented by authors in the first (54 %), last (53 %), and any authorship (53 %) positions. The United States of America had the strongest collaborative partnerships with Botswana, followed by the United Kingdom and South Africa. The majority of funding institutions were American (76 %) and the National Institutes of Health was the most mentioned funding organization, accounting for 33 % of all financial acknowledgments. Only 9 % of the funding acknowledgments came from Botswana. CONCLUSION AND POLICY SUMMARY: Although cancer research in Botswana is expanding because of substantial foreign assistance, it is also hampered by a lack of local funding, minimal participation by Botswana-affiliated researchers, and research that is not aligned with disease burden. Our study highlights the need to strengthen local research capacity in Botswana.

Cervical human papillomavirus genotypes in a high HIV setting: A scoping review of a decade of human papillomavirus epidemiological research in Botswana.

Cervical cancer burden is still high in low- and middle-income countries, including Botswana. Persistent human papillomavirus (HPV) infection is the leading cause of cervical cancer. Accurate knowledge of HPV diversity associated to cervical cancer in sub-Saharan Africa may provide accurate understanding of the natural history of HPV infection in these contexts. The goal of this review was to consolidate existing evidence on cervical HPV infection and to conduct a pooled analysis of data from all eligible Botswana studies. After a successful review of twelve studies on cervical HPV genotypes that met the inclusion criteria, HPV-16 genotype was the most frequently discovered in women with pre-cancerous and cancer lesions, followed by HPV-18. HPV-16 in HIV-positive women with precancerous lesions to cancer is between 45% and 47.7%, and between 4.5% and 26.1% for HPV-18. With reference to other HPV genotypes, the proportion of HPV-35 and HPV-58 (13-16%) seems relatively consistent among the studies, however HPV-58 appears to be more common in HIV-positive subjects compared to HIV-negative women. Indeed, HPV-45 seems to be frequently detected in women with cervical cancer compared to women with precancerous lesions. Regarding the low-risk HPV genotypes, an appropriate breakdown has been provided. In conclusion, the current prophylactic vaccines against HPV-16 and HPV-18, which have demonstrated good immunogenicity in HIV-infected populations, may still prevent infection and ultimately cancer.

The role of CYP2B6 516G>T polymorphism on efavirenz/nevirapine toxicity. Implications on treatment outcomes: Lessons from Botswana.

ABSTRACT: The two non-nucleoside reverse transcriptase inhibitors (NNRTIs), efavirenz (EFV) and nevirapine (NVP), are currently the core antiretroviral drugs for treatment of HIV in sub-Saharan Africa including Botswana. The drugs are metabolized by Cytochrome P450 2B6 (CYP2B6) liver enzyme. The CYP2B6 gene that encodes for metabolism of these drugs is known to be highly polymorphic. One of the polymorphism in the CYP2B6 gene, 516G>T, particularly the 516T allele, is known to confer poor metabolism of EFV and NVP. This may lead to high levels of plasma drug concentrations and development of treatment toxicities, like central nervous system toxicities, and cutaneous and hepatic toxicities, for EFV and NVP, respectively. The CYP2B6 516G allele on the other hand is associated with an extensive metabolism of the two NNRTIs drugs. We sought to establish association between possible developments of NNRTIs toxicities with CYP2B6 516G>T variation in Botswana.A total of 316 peripheral blood mononuclear cells samples were used in a retrospective view. All the samples were from participants on EFV/NVP-containing regimen with known toxicity output. TaqMan Real-Time PCR approach was applied for assessing CYP2B6 516 allele variation in cases with treatment toxicity and those without. Analysis was performed by chi-square statistics and logistic regression analysis.The rate of poor metabolizers among participants with toxicity and those without toxicity was 18.4% and 15.1%, respectively. The CYP2B6 516 genotype distribution comparisons between the participants with toxicity and those without were not statistically different (chi-square = .326; P = .568).CYP2B6 516 variation was not associated with NNRTI toxicity. No other factors were associated with toxicity when considering age, baseline body mass index, baseline CD4, baseline HIV viral load and adherence. The results were discussed in the context of all the studies done in Botswana to date.

Promoter Hypermethylation Analysis of Host Genes in Cervical Cancer Patients With and Without Human Immunodeficiency Virus in Botswana.

Background: Epidemics of human immunodeficiency virus (HIV) and cervical cancer are interconnected. DNA hypermethylation of host genes' promoter in cervical lesions has also been recognized as a contributor to cervical cancer progression. Methods: For this purpose we analyzed promoter methylation of four tumor suppressor genes (RARB, CADM1, DAPK1 and PAX1) and explored their possible association with cervical cancer in Botswana among women of known HIV status. Overall, 228 cervical specimens (128 cervical cancers and 100 non-cancer subjects) were used. Yates-corrected chi-square test and Fisher's exact test were used to explore the association of promoter methylation for each host gene and cancer status. Subsequently, a logistic regression analysis was performed to find which factors, HIV status, high risk-HPV genotypes, patient's age and promoter methylation, were associated with the following dependent variables: cancer status, cervical cancer stage and promoter methylation rate. Results: In patients with cervical cancer the rate of promoter methylation observed was greater than 64% in all the genes studied. Analysis also showed a higher risk of cervical cancer according to the increased number of methylated promoter genes (OR = 6.20; 95% CI: 3.66-10.51; P < 0.001). RARB methylation showed the strongest association with cervical cancer compared to other genes (OR = 15.25; 95% CI: 6.06-40.0; P < 0.001). Cervical cancer and promoter methylation of RARB and DAPK1 genes were associated with increasing age (OR = 1.12; 95% CI: 1.01-1.26; P = 0.037 and OR = 1.05; 95% CI: 1.00-1.10; P = 0.040). The presence of epigenetic changes at those genes appeared to be independent of HIV status among subjects with cervical cancer. Moreover, we found that cervical cancer stage was influenced by RARB (χ2= 7.32; P = 0.002) and CADM1 (χ2=12.68; P = 0.013) hypermethylation, and HIV status (χ2= 19.93; P = 0.001). Conclusion: This study confirms the association between invasive cervical cancer and promoter gene methylation of tumor suppressing genes at the site of cancer. HIV infection did not show any association to methylation changes in this group of cervical cancer patients from Botswana. Further studies are needed to better understand the role of HIV in methylation of host genes among cancer subjects leading to cervical cancer progression.

Similar Ferroportin Q248H polymorphism prevalence in patients with Plasmodium falciparum malaria and control subjects in the low-endemic setting of Botswana.

INTRODUCTION: Recent evidence suggests that ferroportin (FPN) Q248H may confer a survival advantage against malaria by reducing erythrocytic intracellular iron in Africans. We investigated if FPN Q248H mutation, that is prevalent in Batswana, is a factor in limiting the susceptibility to Plasmodium falciparum malaria. METHODS: 264 archived dried blood spot samples (183 P. falciparum malaria cases and 81 controls, matched for geographical region and season for equal exposure) were genotyped. Human and P. falciparum DNA was extracted using Chelex-100 resin and P. falciparum molecular confirmation performed. Ferroportin Q248H mutation was identified by restriction fragment length polymorphism. The prevalence of the FPN Q248H mutation and allele frequency and the accompanying 95% confidence interval were calculated. A qPCR method was employed to estimate P. falciparum parasitaemia. Association between FPN and malaria susceptibility was tested using Pearson Chi-square test and Mood's median test was used to compare P. falciparum parasitaemias according to FPN Q248H mutation. RESULTS: All samples were successfully genotyped. The FPN Q248H allele frequency was 0.08 (95% CI: 0.05-0.11) in cases and 0.08 (95% CI: 0.02-0.14) in controls, consistent with Hardy-Weinberg equilibrium. The prevalence of FPN Q248H phenotype was comparable in patients with P. falciparum malaria and in un-infected individuals, 16.4% (95% CI: 11.0-21.8) vs 14.8% (95% CI: 7.1-22.5), P = 0.746. In addition, no association of presence of FPN Q248H with reduced parasitaemia was recorded, P = 0.837. CONCLUSION: In this small study, FPN Q248H polymorphism prevalence was comparable between patients with P. falciparum malaria and control subjects in the low-endemic setting of Botswana.

Association of CYP2B6 Genetic Variation with Efavirenz and Nevirapine Drug Resistance in HIV-1 Patients from Botswana.

PURPOSE: CYP2B6 liver enzyme metabolizes the two non-nucleoside reverse transcriptase inhibitors Efavirenz (EFV) and Nevirapine (NVP) used in the antiretroviral therapy (ART) regimens for HIV-infected individuals. Polymorphisms of the CYP2B6 gene influence drug levels in plasma and possibly virological outcomes. The aim of this study was to explore the potential impact of CYP2B6 genotype and haplotype variation on the risk of developing EFV/NVP drug resistance mutations (DRMs) in HIV-1 patients receiving EFV-/NVP-containing regimens in Botswana. PATIENTS AND METHODS: Participants were a sub-sample of a larger study (Tshepo study) conducted in Gaborone, Botswana, among HIV-infected individuals taking EFV/NVP containing ART. Study samples were retrieved and assigned to cases (with DRMs) and controls (without DRMs). Four single-nucleotide polymorphisms (SNPs) in the CYP2B6 gene (-82T>C; 516G>T; 785A>G; 983T>C) were genotyped, the haplotypes reconstructed, and the metabolic score assigned. The possible association between drug resistance and several independent factors (baseline characteristics and CYP2B6 genotypes) was assessed by Binary Logistic Regression (BLR) analysis. EFV/NVP resistance status and CYP2B6 haplotypes were also analyzed using Z-test, chi-square and Fisher's exact test statistics. RESULTS: Two hundred and twenty-seven samples were analysed (40 with DRMs, 187 without DRMs). BLR analysis showed an association between EFV/NVP resistance and CYP2B6 516G allele (OR: 2.26; 95% CI: 1.27-4.01; P=0.005). Moreover, haplotype analysis revealed that the proportion of EFV/NVP-resistant infections was higher among CYP2B6 fast than extensive/slow metabolizers (30.8% vs 16.8%; P=0.035), with the 516G allele more represented in the haplotypes of fast than extensive/slow metabolizers (100.0% vs 53.8%; P<0.001). CONCLUSION: We demonstrated that the CYP2B6 516G allele, and even more when combined in fast metabolic haplotypes, is associated with the presence of EFV/NVP resistance, strengthening the need to assess the CYP2B6 genetic profiles in HIV-infected patients in order to improve the virologic outcomes of NNRTI containing ART.

Past and current biological factors affecting malaria in the low transmission setting of Botswana: A review.

Malaria continues to be one of the top infectious agents contributing to morbidity and mortality in sub-Saharan Africa. Annually, Botswana accounts only for a small proportion of cases (<<1%). Despite significantly reduced incidence rate, the country still experiences sporadic outbreaks that hamper the goal of malaria elimination. This review evaluated previous and current biological factors that impact malaria in Botswana, specifically focussing on the vectors, the parasite and the host. This was accomplished via a literature review evaluating these variables in Botswana. Current literature suggests that Anopheles arabiensis is the main malaria vector in the country. Several other potential vectors have been found widely distributed throughout Botswana in high numbers, yet remain largely unstudied with regards to their contribution to the country's malaria burden. We also report the most up to date list of all Anopheles species that have been found in Botswana. Plasmodium falciparum is responsible for the vast majority of symptomatic malaria in the country and some drug resistance markers have been documented for this species. Plasmodium vivax has been reported in asymptomatic subjects, even though a large proportion of the Botswana population appears to be Duffy antigen negative. Very little is known about the true distribution of P. vivax and no point of care testing infrastructure for this species exists in Botswana, making it difficult to tailor treatment to address possible recrudescence or relapse. Due to a genetically diverse population with a substantial Khoisan contribution into the Bantu genetic background, several phenotypes that potentially impact prevalence and severity of malaria exist within the country. These include sickle cell trait, Glucose-6-Phosphate Dehydrogenase deficiency, and Duffy negativity. This review highlights the information that currently exists on malaria in Botswana. It also postulates that a comprehensive understanding of these aforementioned biological factors may help to explain malaria persistence in Botswana.