Publications by authors named "Tiemessen C"

Background: Currently, most HIV drug resistance PCR assays amplify the protease-reverse transcriptase (PR-RT) fragment separately from the integrase (IN) fragment. The aim of this study was to develop a multiplex PCR assay that simultaneously amplifies PR-RT and IN fragments for HIV-1 drug-resistance testing.

Methods: The in-house multiplex PCR assay was evaluated on extracted total nucleic acids obtained from the National Health Laboratory Service (NHLS) and Lancet laboratories.

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Article Synopsis
  • The study investigates the immune response to SARS-CoV-2 in pregnant women, specifically focusing on unvaccinated Black African women living with HIV (WLWH) and HIV-uninfected women.
  • Researchers analyzed T-cell responses to both the original strain of the virus and the Omicron variant, finding similar responses in both groups.
  • Results indicate that T-cell immunity is maintained across different virus strains, emphasizing that both WLWH and HIV-uninfected pregnant women show comparable immune responses to previous infections.
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Background: HIV type 1 ((human immunodeficiency virus) HIV-1) elite controllers (ECs) are a rare subset of people living with HIV-1 (PLWH) who control viral replication in the absence of antiretroviral treatment (ART) and may provide a model for a functional cure. We investigated the role of natural killer (NK) cells in HIV-1 ECs from South Africa.

Methods: Phenotypic (CD69, CD38, CD57, PD-1), functional (CD107a, IFN-γ (inferferon gamma)), and nutrient transporter profiles (glucose transporter 1, CD98) of NK cells from ECs (n = 20), viremic progressors (VPs; n = 19), PLWH on ART (n = 20), and people without HIV-1 (PWOH; n = 21) were analyzed using flow cytometry.

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Analytical treatment interruption (ATI) is widely acknowledged as an essential component of studies to advance our understanding of HIV cure, but discussion has largely been focused on adults. To address this gap, we reviewed evidence related to the safety and utility of ATI in paediatric populations. Three randomised ATI trials using CD4 T-cell and clinical criteria to guide restart of antiretroviral therapy (ART) have been conducted.

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Structural variants are responsible for a large part of genomic variation between individuals and play a role in both common and rare diseases. Databases cataloguing structural variants notably do not represent the full spectrum of global diversity, particularly missing information from most African populations. To address this representation gap, we analysed 1,091 high-coverage African genomes, 545 of which are public data sets, and 546 which have been analysed for structural variants for the first time.

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Background: With the advent of antiretroviral therapy (ART), most children living with HIV in sub-Saharan Africa (SSA) are growing toward adolescence, with scarcity of evidence on the size of viral reservoirs to enhance paediatric cure research strategies. This study aims to compare HIV-1 proviral DNA levels according to virological response among adolescents living with perinatally acquired HIV-1 (ALPHIV) and identify associated-factors in the Cameroonian context.

Methods: In this observational cohort study, HIV-1 RNA viremia and CD4 T-cell count were assessed through RT-PCR and flow cytometry respectively at three time-points over 18 months of observation.

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Article Synopsis
  • Low- and middle-income countries (LMICs), particularly in Southern and Eastern Africa, face the highest global HIV burden but have limited research efforts focused on HIV cure.
  • *Conducting studies in these regions provides opportunities to develop tailored research strategies, involve local stakeholders, and create impactful policies due to the diverse HIV strains and high prevalence.
  • *Challenges such as lack of funding, mentorship, and infrastructure limit the participation of early-career investigators in HIV cure research, highlighting the need for capacity building and collaboration with international peers.*
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  • The study aimed to examine how early antiretroviral therapy (ART) affects the growth of infants diagnosed with HIV during their first year.
  • Researchers followed 116 HIV-infected infants and 80 uninfected infants born to mothers with HIV in Johannesburg, analyzing their growth through 48 weeks.
  • Results showed that HIV-infected infants had significantly lower weight and length compared to the uninfected group, particularly highlighted in girls, and higher viral loads before treatment were linked to poorer growth outcomes.
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Objective: CCR5-tropic viruses are preferentially transmitted during perinatal HIV-1 infection. CCR5 density on CD4 + T-cells likely impacts susceptibility to HIV-1 infection.

Design: Fifty-two mother-infant dyads were enrolled.

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Article Synopsis
  • The study aimed to systematically review HIV-1 reservoirs in children and adolescents with perinatally acquired HIV, analyzing published data from various studies between 2002 and 2022.
  • A total of 49 studies involving over 2,300 participants were included, revealing a high prevalence of archived-drug resistance mutations (ADRMs) across different regions, with significant findings regarding early antiretroviral therapy (ART) initiation impacting HIV-1 DNA levels.
  • The conclusions emphasized that high ADRM prevalence and larger viral reservoirs are associated with late ART initiation and shorter periods of viral suppression, suggesting the need for early ART strategies in pediatric populations to improve treatment outcomes.
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Genetic variation in CYP2B6 and CYP2A6 is known to impact interindividual response to antiretrovirals, nicotine, and bupropion, among other drugs. However, the full catalogue of clinically relevant pharmacogenetic variants in these genes is yet to be established, especially across African populations. This study therefore aimed to characterize the star allele (haplotype) distribution in CYP2B6 and CYP2A6 across diverse and understudied sub-Saharan African (SSA) populations.

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Introduction: The success of antiretroviral therapy (ART) has changed HIV from a deadly to a chronic infection, thus increasing the transitioning from infancy toward adulthood. However, the virostatic nature of antiretrovirals maintains viruses in sanctuaries, with reactivation potentials. Because current ARTs are very limited for children, the emergence of new HIV epidemics driven by HIV drug-resistance mutations is favoured.

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Antiretroviral therapy (ART) has improved the lifespan of people living with HIV. However, their immune system remains in a state of sustained activation/inflammation, which favors viral replication and depletion of helper T-cells with varying profiles according to ART-response. We herein sought to ascertain the inflammatory profile of adolescents living with perinatal HIV-1 infection (ALPHI) receiving ART in an African context.

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Background: Identification of proinflammatory factors responding to Mycobacterium tuberculosis is important to reduce long-term sequelae of pulmonary tuberculosis (TB).

Methods: We examined the association between plasma biomarkers, the fraction of exhaled nitric oxide (FeNO), and lung function among a prospective cohort of 105 adults newly diagnosed with TB/human immunodeficiency virus (HIV) in South Africa. Participants were followed for 48 weeks from antiretroviral therapy (ART) initiation with serial assessments of plasma biomarkers, FeNO, lung function, and respiratory symptoms.

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  • Infancy is a critical period for the development of the microbiome, and this study investigates how early antiretroviral therapy (ART) affects oral microbiota in children with HIV compared to uninfected controls.
  • Children with HIV showed reduced microbial diversity and different bacterial abundances, particularly in boys, but earlier ART initiation did not significantly improve their microbiota profile.
  • The findings highlight that the ART regimen currently used may have a more pronounced impact on oral microbiota than the age at which therapy began.
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Background: Patients with tuberculosis (TB) and HIV often present with impairments in lung function and exercise capacity after treatment. We evaluated clinical and immunologic variables associated with a minimum clinically important difference (MCID) in the change in the 6 min walk test distance during the first 24 weeks of antiretroviral (ART) and anti-tubercular therapy.

Methods: Adults initiating ART and anti-TB treatment in the setting of newly-diagnosed HIV and pulmonary TB were enrolled in a prospective cohort study in South Africa.

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Host genetic factors are known to modify the susceptibility, severity, and outcomes of COVID-19 and vary across populations. However, continental Africans are yet to be adequately represented in such studies despite the importance of genetic factors in understanding Africa's response to the pandemic. We describe the development of a research resource for coronavirus host genomics studies in South Africa known as COVIGen-SA-a multicollaborator strategic partnership designed to provide harmonised demographic, clinical, and genetic information specific to Black South Africans with COVID-19.

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Cytochrome P450 2D6 (CYP2D6) is a key enzyme in drug response owing to its involvement in the metabolism of ~ 25% of clinically prescribed medications. The encoding CYP2D6 gene is highly polymorphic, and many pharmacogenetics studies have been performed worldwide to investigate the distribution of CYP2D6 star alleles (haplotypes); however, African populations have been relatively understudied to date. In this study, the distributions of CYP2D6 star alleles and predicted drug metabolizer phenotypes-derived from activity scores-were examined across multiple sub-Saharan African populations based on bioinformatics analysis of 961 high-depth whole genome sequences.

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Background: Some mother-to-child transmission (MTCT) studies suggest that allelic variations of Fc gamma receptors (FcγR) play a role in infant HIV-1 acquisition, but findings are inconsistent. To address the limitations of previous studies, the present study investigates the association between perinatal HIV-1 transmission and FcγR variability in three cohorts of South African infants born to women living with HIV-1.

Methods: This nested case-control study combines FCGR genotypic data from three perinatal cohorts at two hospitals in Johannesburg, South Africa.

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In 2019 there were 490,000 children under five living with HIV. Understanding the dynamics of HIV suppression and rebound in this age group is crucial to optimizing treatment strategies and increasing the likelihood of infants achieving and sustaining viral suppression. Here we studied data from a cohort of 122 perinatally-infected infants who initiated antiretroviral treatment (ART) early after birth and were followed for up to four years.

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Background: Asymptomatic cryptococcal antigenemia (positive blood cryptococcal antigen [CrAg]) is associated with increased mortality in individuals with human immunodeficiency virus (HIV) even after adjusting for CD4 count and despite receiving antifungal treatment. The association of antibody immunity with mortality in adults with HIV with cryptococcal antigenemia is unknown.

Methods: Cryptococcal capsular glucuronoxylomannan (GXM)- and naturally occurring β-glucans (laminarin, curdlan)-binding antibodies were measured in blood samples of 197 South Africans with HIV who underwent CrAg screening and were followed up to 6 months.

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HIV-1 incidence is an important parameter for assessing the impact of HIV-1 interventions. The aim of this study was to evaluate HIV-1 polymerase (pol) gene sequence diversity for the prediction of recent HIV-1 infections. Complete pol Sanger sequences obtained from 45 participants confirmed to have recent or chronic HIV-1 infection were used.

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The greater mortality risk among people with advanced human immunodeficiency virus disease and cryptococcal antigenemia, despite treatment, indicates an increased susceptibility to other infections. We found that prior tuberculosis was an independent risk factor for cryptococcal antigenemia (adjusted odds ratio, 2.72; 95% confidence interval, 1.

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