RESUMEN
Continued uncontrolled transmission of SARS-CoV-2 in many parts of the world is creating conditions for substantial evolutionary changes to the virus1,2. Here we describe a newly arisen lineage of SARS-CoV-2 (designated 501Y.V2; also known as B.1.351 or 20H) that is defined by eight mutations in the spike protein, including three substitutions (K417N, E484K and N501Y) at residues in its receptor-binding domain that may have functional importance3-5. This lineage was identified in South Africa after the first wave of the epidemic in a severely affected metropolitan area (Nelson Mandela Bay) that is located on the coast of the Eastern Cape province. This lineage spread rapidly, and became dominant in Eastern Cape, Western Cape and KwaZulu-Natal provinces within weeks. Although the full import of the mutations is yet to be determined, the genomic data-which show rapid expansion and displacement of other lineages in several regions-suggest that this lineage is associated with a selection advantage that most plausibly results from increased transmissibility or immune escape6-8.
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COVID-19/virología , Mutación , Filogenia , Filogeografía , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , COVID-19/epidemiología , COVID-19/inmunología , COVID-19/transmisión , Análisis Mutacional de ADN , Evolución Molecular , Aptitud Genética , Humanos , Evasión Inmune , Modelos Moleculares , SARS-CoV-2/inmunología , SARS-CoV-2/patogenicidad , Selección Genética , Sudáfrica/epidemiología , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo , Factores de TiempoRESUMEN
HIV drug resistance mutations (HIVDRMs) are important determinants of therapeutic effects and outcomes even in end-stage kidney failure (ESKF) people living with HIV (PLWHIV). This study evaluated the prevalence of HIVDRMs and their effect on the shedding of HIV-1 into peritoneal dialysis (PD) effluents. This cross-sectional study of PLWHIV and having ESKF and managed with antiretroviral therapy (ART) and PD, collected enrolled patients' demographic information, clinical and laboratory data, and sequenced HIV-1 RNA in unsuppressed plasma and PD effluent samples. HIV viral load and HIVDRMs were determined using qualitative polymerase chain reaction (qPCR) and Stanford University HIVDRM Database, respectively. There were 60 participants recruited with a median age of 43.0 (interquartile range [IQR], 38.0-47) years and were predominantly on abacavir (88.3%), lamivudine (98.3%), and efavirenz (70%) for a median duration of 8 (IQR, 5-11) years. Among participants with detectable HIV-1 in PD effluents, the prevalence of HIVDRMs was 62.5% (5/8) compared to 7.7% (4/52) among those with undetectable HIV-1 (p = 0.001) with non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations predominating. On Spearman's correlation analysis, high plasma HIV levels (ρ = 0.649, p < 0.001), T-cell CD4 count (ρ = -0370, p < 0.004), serum creatinine (ρ = -0.396, p < 0.002), and white blood cell count (ρ = -0.294, p < 0.023) levels were significant factors correlated with the detection of HIV-1 in PD effluents. Moreover, HIVDRMs presence (ρ = 0.504, p < 0.001) particularly NNRTI resistance (ρ = 0.504, p < 0.001) were also significantly correlated with detection of HIV-1 in PD effluents. The presence of HIVDRMs, high plasma HIV viral load, and T-cell CD4 count were correlated with HIV-1 shedding into PD effluents.
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Farmacorresistencia Viral , Infecciones por VIH , VIH-1 , Mutación , Diálisis Peritoneal , Carga Viral , Esparcimiento de Virus , Humanos , VIH-1/genética , VIH-1/efectos de los fármacos , Masculino , Infecciones por VIH/virología , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Femenino , Estudios Transversales , Persona de Mediana Edad , Adulto , Farmacorresistencia Viral/genética , Prevalencia , ARN Viral/genética , Fármacos Anti-VIH/uso terapéutico , Fármacos Anti-VIH/farmacología , Fallo Renal Crónico/terapia , Recuento de Linfocito CD4RESUMEN
Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) is listed as a priority pathogen by the World Health Organization due to the severity of disease, propensity for spread to nonendemic regions, and absence of a vaccine or specific treatment. The immune correlates of protection are not clearly defined and hence the importance of investigating host immune responses in survivors. We have previously shown that survivors generate memory T cell responses that are long-lived and this study aimed to further define specific viral proteins targeted by the T cell response. The NSM , GP38, highly variable mucin-like domain, and N-terminus of GC regions in CCHFV are considered immunogenic regions and were investigated using peptide libraries representing regions of interest. An interferon gamma ELISpot assay was used to identify responses in peripheral blood mononuclear cells isolated from 12 survivors of laboratory confirmed CCHFV infections. IFN-γ responses were detected from eight survivors, against nine peptides, including four peptides located in the NSM region and five peptides located in the GP38 protein. No response was detected against peptides representing the mucin-like domain. In conclusion, the results suggest the presence of a long-lasting T cell memory response upon stimulation with viral epitopes in survivors of infection.
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Fiebre Hemorrágica de Crimea , Humanos , Sudáfrica , Leucocitos Mononucleares , Linfocitos T , Glicoproteínas , Mucinas , Biblioteca de Péptidos , SobrevivientesRESUMEN
We report a higher percentage of Sindbis virus-specific IgG in serum from patients attending a rheumatology clinic (18.8%) compared with healthy residents (9.6%) and patients with acute febrile illness (9.4%) in Free State Province, South Africa. Sindbis virus infection should be considered a potential cause of arthritis in South Africa.
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Anticuerpos Antivirales , Virus Sindbis , Humanos , Inmunoglobulina G , Estudios Seroepidemiológicos , Sudáfrica/epidemiologíaRESUMEN
Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) amplicon contamination was discovered due to next-generation sequencing (NGS) reads mapping in the negative controls. Environmental screening was undertaken to determine the source of contamination, which was suspected to be evaporation during polymerase chain reaction (PCR) assays while using the coronavirus disease 2019 (COVID-19) ARTIC protocol. A decontamination strategy is hereby documented to assist laboratories that may experience similar amplicon contamination. Routine molecular laboratory environmental screening as a quality control is highly recommended.
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COVID-19 , Laboratorios , COVID-19/prevención & control , Descontaminación , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , SARS-CoV-2/genéticaRESUMEN
Crimean-Congo hemorrhagic fever virus (CCHFV) causes severe disease with fatalities. Awareness of potential sources of infection is important to reduce risk to healthcare workers and contacts. We detected CCHFV RNA in formalin-fixed, paraffin-embedded tissues from a spontaneous abortion that were submitted for histology 9 weeks after a suspected CCHFV infection in the mother.
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Aborto Espontáneo , Virus de la Fiebre Hemorrágica de Crimea-Congo/patogenicidad , Fiebre Hemorrágica de Crimea/diagnóstico , Complicaciones Infecciosas del Embarazo/diagnóstico , Diagnóstico Diferencial , Femenino , Fiebre Hemorrágica de Crimea/virología , Humanos , Embarazo , Complicaciones Infecciosas del Embarazo/virología , Diagnóstico Prenatal , SudáfricaRESUMEN
BACKGROUND: International Sustainable Development Goals (SDGs) for elimination of hepatitis B virus (HBV) infection set ambitious targets for 2030. In African populations, infant immunisation has been fundamental to reducing incident infections in children, but overall population prevalence of chronic hepatitis B (CHB) infection remains high. In high-prevalence populations, adult catch-up vaccination has sometimes been deployed, but an alternative Test and Treat (T&T) approach could be used as an intervention to interrupt transmission. Universal T&T has not been previously evaluated as a population intervention for HBV infection, despite high-profile data supporting its success with human immunodeficiency virus (HIV). METHODS AND FINDINGS: We set out to investigate the relationship between prevalence of HBV infection and exposure in Africa, undertaking a systematic literature review in November 2019. We identified published seroepidemiology data representing the period 1995-2019 from PubMed and Web of Science, including studies of adults that reported prevalence of both hepatitis B surface antigen (HBsAg; prevalence of HBV infection) and antibody to hepatitis B core antigen (anti-HBc; prevalence of HBV exposure). We identified 96 studies representing 39 African countries, with a median cohort size of 370 participants and a median participant age of 34 years. Using weighted linear regression analysis, we found a strong relationship between the prevalence of infection (HBsAg) and exposure (anti-HBc) (R2 = 0.45, p < 0.001). Region-specific differences were present, with estimated CHB prevalence in Northern Africa typically 30% to 40% lower (p = 0.007) than in Southern Africa for statistically similar exposure rates, demonstrating the need for intervention strategies to be tailored to individual settings. We applied a previously published mathematical model to investigate the effect of interventions in a high-prevalence setting. The most marked and sustained impact was projected with a T&T strategy, with a predicted reduction of 33% prevalence by 20 years (95% CI 30%-37%) and 62% at 50 years (95% CI 57%-68%), followed by routine neonatal vaccination and prevention of mother to child transmission (PMTCT; at 100% coverage). In contrast, the impact of catch-up vaccination in adults had a negligible and transient effect on population prevalence. The study is constrained by gaps in the published data, such that we could not model the impact of antiviral therapy based on stratification by specific clinical criteria and our model framework does not include explicit age-specific or risk-group assumptions regarding force of transmission. CONCLUSIONS: The unique data set collected in this study highlights how regional epidemiology data for HBV can provide insights into patterns of transmission, and it provides an evidence base for future quantitative research into the most effective local interventions. In combination with robust neonatal immunisation programmes, ongoing PMTCT efforts, and the vaccination of high-risk groups, diagnosing and treating HBV infection is likely to be of most impact in driving advances towards elimination targets at a population level.
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Anticuerpos contra la Hepatitis B/sangre , Vacunas contra Hepatitis B/administración & dosificación , Virus de la Hepatitis B , Hepatitis B/sangre , Hepatitis B/epidemiología , África/epidemiología , Infecciones por VIH/sangre , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Hepatitis B/prevención & control , Humanos , Estudios Seroepidemiológicos , Vacunación/métodosRESUMEN
Human papillomaviruses (HPVs) have been associated with a subset of head and neck squamous cell carcinomas (HNSCCs). The aim of this study was to determine the prevalence of HPV DNA in archived formalin-fixed paraffin-embedded tissue from patients with histologically confirmed HNSCCs in a South African cohort. A nested PCR was used for the detection of HPV DNA targeting the L1 gene. Positive samples were confirmed using an in-house hemi-nested PCR targeting the E6 gene and genotyped by sequence determination of amplicons. HPV DNA was detected in 57/780 (7.3%) samples, with the highest prevalence being in the sinonasal tract (16.0%) and oropharynx (10.8%). HPV16 was the most frequently detected type, being found in 26/57 (45.6%) positive samples. The prevalence of HPV DNA in HNSCCs found in this study was lower than that found in developed countries.
Asunto(s)
Alphapapillomavirus/aislamiento & purificación , ADN Viral/aislamiento & purificación , Neoplasias de Cabeza y Cuello/virología , Carcinoma de Células Escamosas de Cabeza y Cuello/virología , Adulto , Anciano , Anciano de 80 o más Años , Alphapapillomavirus/clasificación , Alphapapillomavirus/genética , ADN Viral/genética , Genotipo , Neoplasias de Cabeza y Cuello/epidemiología , Humanos , Persona de Mediana Edad , Infecciones por Papillomavirus/epidemiología , Infecciones por Papillomavirus/virología , Sudáfrica/epidemiología , Carcinoma de Células Escamosas de Cabeza y Cuello/epidemiología , Adulto JovenRESUMEN
BACKGROUND: International sustainable development goals for the elimination of viral hepatitis as a public health problem by 2030 highlight the need to optimize strategies for prevention, diagnosis and treatment of hepatitis B virus (HBV) infection. An important priority for Africa is to have affordable, accessible and sustainable prevention of mother to child transmission (PMTCT) programmes, delivering screening and treatment for antenatal women and implementing timely administration of HBV vaccine for their babies. METHODS: We developed a decision-analytic model simulating 10,000 singleton pregnancies to assess the cost-effectiveness of three possible strategies for deployment of tenofovir in pregnancy, in combination with routine infant vaccination: S1: no screening nor antiviral therapy; S2: screening and antiviral prophylaxis for all women who test HBsAg-positive; S3: screening for HBsAg, followed by HBeAg testing and antiviral prophylaxis for women who are HBsAg-positive and HBeAg-positive. Our outcome was cost per infant HBV infection avoided and the analysis followed a healthcare perspective. RESULTS: Based on 10,000 pregnancies, S1 predicts 45 infants would be HBV-infected at six months of age, compared to 21 and 28 infants in S2 and S3, respectively. Relative to S1, S2 had an incremental cost of $3940 per infection avoided. S3 led to more infections and higher costs. CONCLUSION: Given the long-term health burden for individuals and economic burden for society associated with chronic HBV infection, screening pregnant women and providing tenofovir for all who test HBsAg+ may be a cost-effective strategy for South Africa and other low/middle income settings.
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Antivirales/uso terapéutico , Análisis Costo-Beneficio , Virus de la Hepatitis B/inmunología , Hepatitis B/tratamiento farmacológico , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Tenofovir/uso terapéutico , Adulto , Niño , Países en Desarrollo , Femenino , Hepatitis B/sangre , Hepatitis B/diagnóstico , Hepatitis B/virología , Antígenos de Superficie de la Hepatitis B/sangre , Vacunas contra Hepatitis B/administración & dosificación , Antígenos e de la Hepatitis B/sangre , Hepatitis B Crónica/sangre , Hepatitis B Crónica/diagnóstico , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis B Crónica/virología , Humanos , Lactante , Tamizaje Masivo , Modelos Biológicos , Embarazo , Complicaciones Infecciosas del Embarazo/sangre , Complicaciones Infecciosas del Embarazo/diagnóstico , Complicaciones Infecciosas del Embarazo/virología , Sudáfrica , Tenofovir/economía , Vacunación , Adulto JovenRESUMEN
Background: Human immunodeficiency virus (HIV)-infected individuals have a higher risk of developing active tuberculosis (TB) than HIV-uninfected individuals, but the mechanisms underpinning this are unclear. We hypothesized that depletion of specific components of Mycobacterium tuberculosis (Mtb)-specific CD4+ and CD8+ T-cell responses contributed to this increased risk. Methods: Mtb-specific T-cell responses in 147 HIV-infected and 44 HIV-uninfected control subjects in a TB-endemic setting in Bloemfontein, South Africa, were evaluated. Using a whole-blood flow cytometry assay, we measured expression of interferon gamma, tumor necrosis factor alpha, interleukin 2, and interleukin 17 in CD4+ and CD8+ T cells in response to Mtb antigens (PPD, ESAT-6/CFP-10 [EC], and DosR regulon-encoded α-crystallin [Rv2031c]). Results: Fewer HIV-infected individuals had detectable CD4+ and CD8+ T-cell responses to PPD and Rv2031c than HIV-uninfected subjects. Mtb-specific T cells showed distinct patterns of cytokine expression comprising both Th1 (CD4 and CD8) and Th17 (CD4) cytokines, the latter at highest frequency for Rv2031c. Th17 antigen-specific responses to all antigens tested were specifically impaired in HIV-infected individuals. Conclusions: HIV-associated impairment of CD4+ and CD8+Mtb-specific T-cell responses is antigen specific, particularly impacting responses to PPD and Rv2031c. Preferential depletion of Th17 cytokine-expressing CD4+ T cells suggests this T-cell subset may be key to TB susceptibility in HIV-infected individuals.
Asunto(s)
Infecciones por VIH/inmunología , Mycobacterium tuberculosis/inmunología , Subgrupos de Linfocitos T/inmunología , Células TH1/inmunología , Células Th17/inmunología , Tuberculosis/inmunología , Adulto , Antígenos Bacterianos/inmunología , Coinfección/inmunología , Coinfección/microbiología , Coinfección/virología , Citocinas/inmunología , Femenino , VIH/inmunología , Infecciones por VIH/microbiología , Humanos , Interferón gamma/inmunología , Masculino , Persona de Mediana Edad , Sudáfrica , Tuberculosis/microbiología , Tuberculosis/virología , Adulto JovenRESUMEN
Crimean Congo hemorrhagic fever virus (CCHFV) is endemic in South Africa, but whether mild undiagnosed cases occur is unclear. In a seroepidemiologic survey, only 2 of 387 adults considered at risk because of occupational or recreational activities had evidence of previous infection. Seroprevalence in South Africa remains low within the groups investigated.
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Virus de la Fiebre Hemorrágica de Crimea-Congo/inmunología , Fiebre Hemorrágica de Crimea/epidemiología , Fiebre Hemorrágica de Crimea/inmunología , Adolescente , Adulto , Anciano , Femenino , Geografía Médica , Fiebre Hemorrágica de Crimea/virología , Humanos , Inmunoensayo , Inmunoglobulina G/inmunología , Masculino , Persona de Mediana Edad , Vigilancia en Salud Pública , Factores de Riesgo , Estudios Seroepidemiológicos , Sudáfrica/epidemiología , Adulto JovenRESUMEN
Crimean-Congo haemorrhagic fever virus (CCHFV) is a member of the Bunyaviridae family with a tripartite, negative sense RNA genome. This study used predictive software to analyse the L (large), M (medium), and S (small) segments of 14 southern African CCHFV isolates. The OTU-like cysteine protease domain and the RdRp domain of the L segment are highly conserved among southern African CCHFV isolates. The M segment encodes the structural glycoproteins, GN and GC, and the non-structural glycoproteins which are post-translationally cleaved at highly conserved furin and subtilase SKI-1 cleavage sites. All of the sites previously identified were shown to be conserved among southern African CCHFV isolates. The heavily O-glycosylated N-terminal variable mucin-like domain of the M segment shows the highest sequence variability of the CCHFV proteins. Five transmembrane domains are predicted in the M segment polyprotein resulting in three regions internal to and three regions external to the membrane across the G(N), NS(M) and G(C) glycoproteins. The corroboration of conserved genome domains and sequence identity among geographically diverse isolates may assist in the identification of protein function and pathogenic mechanisms, as well as the identification of potential targets for antiviral therapy and vaccine design. As detailed functional studies are lacking for many of the CCHFV proteins, identification of functional domains by prediction of protein structure, and identification of amino acid level similarity to functionally characterised proteins of related viruses or viruses with similar pathogenic mechanisms are a necessary step for selection of areas for further study.
Asunto(s)
Variación Genética , Genoma Viral , Virus de la Fiebre Hemorrágica de Crimea-Congo/clasificación , Virus de la Fiebre Hemorrágica de Crimea-Congo/genética , ARN Viral/genética , África Austral , Secuencia Conservada , Virus de la Fiebre Hemorrágica de Crimea-Congo/aislamiento & purificación , Humanos , Modelos Moleculares , Conformación de Ácido Nucleico , Proteínas Virales/genéticaRESUMEN
The seroepidemiology of hepatitis E virus (HEV) in South Africa is limited. We investigated anti-HEV IgM and IgG, in residual hepatitis A, B, and C negative serology specimens, at our public sector Free State (FS) laboratory. Of 299 specimens (01 May-31 October 2020), 182/299 (60.9%) had anti-HEV IgG and 1/299 (0.33%) had anti-HEV IgM. High HEV seroprevalence across different age groups suggests a different epidemiology in the FS, necessitating further research. Contribution: The need for HEV research in South Africa is highlighted. Clinicians should consider HEV in their differential diagnosis of patients with hepatitis.
RESUMEN
Respiratory syncytial virus (RSV) is the most predominant viral pathogen worldwide in children with lower respiratory tract infections. The Coronavirus disease 2019 (COVID-19) pandemic and resulting nonpharmaceutical interventions perturbed the transmission pattern of respiratory pathogens in South Africa. A seasonality shift and RSV resurgence was observed in 2020 and 2021, with several infected children observed. Conventional RSV-positive nasopharyngeal swabs were collected from various hospitals in the Free State province, Bloemfontein, South Africa, from children suffering from respiratory distress and severe acute respiratory infection between 2020 to 2021. Overlapping genome fragments were amplified and complete genomes were sequenced using the Illumina MiSeq platform. Maximum likelihood phylogenetic and evolutionary analysis were performed on both RSV-A/-B G-genes with published reference sequences from GISAID and GenBank. Our study strains belonged to the RSV-A GA2.3.2 and RSV-B GB5.0.5a clades. The upsurge of RSV was due to pre-existing strains that predominated in South Africa and circulating globally also driving these off-season RSV outbreaks during the COVID-19 pandemic. The variants responsible for the resurgence were phylogenetically related to pre-pandemic strains and could have contributed to the immune debt resulting from pandemic imposed restrictions. The deviation of the RSV season from the usual pattern affected by the COVID-19 pandemic highlights the need for ongoing genomic surveillance and the identification of genetic variants to prevent unforeseen outbreaks in the future.
Asunto(s)
COVID-19 , Genoma Viral , Filogenia , Infecciones por Virus Sincitial Respiratorio , Virus Sincitial Respiratorio Humano , SARS-CoV-2 , Secuenciación Completa del Genoma , Sudáfrica/epidemiología , Humanos , COVID-19/epidemiología , COVID-19/virología , Infecciones por Virus Sincitial Respiratorio/epidemiología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitial Respiratorio Humano/genética , Virus Sincitial Respiratorio Humano/clasificación , Virus Sincitial Respiratorio Humano/aislamiento & purificación , SARS-CoV-2/genética , SARS-CoV-2/clasificación , SARS-CoV-2/aislamiento & purificación , Preescolar , Lactante , Niño , Pandemias , Estaciones del Año , Masculino , Femenino , Nasofaringe/virologíaRESUMEN
BACKGROUND: Renally adjusted lamivudine dosages are effective. However, some of the kidney failure patients managed with lamivudine-containing regimens are failing to suppress HIV in peritoneal dialysis (CAPD) effluent. The steady-state lamivudine pharmacokinetics among these patients was evaluated. METHODS: This overnight open-label pharmacokinetic study enrolled participants living with HIV and managed with CAPD. Lamivudine levels in blood serum and CAPD effluent samples were quantified using liquid chromatography coupled with a mass spectrometer. Pharmacokinetic measures were obtained through non-compartmental analysis. RESULTS: Twenty-eight participants were recruited with a median antiretroviral (ARV) drug duration of 8 (IQR,4.5-10.5) years and a CAPD duration of 13.3 (IQR,3.3-31.9) months. 14.3% (4/28) had detectable unsuppressed HIV-1 viral load in CAPD effluents. The majority (78,6%,22/28) of participants received a 50 mg dose, while 10.7% (3/28), and another 10.7% (3/28) received 75 mg and 300 mg dosages, respectively. Among those treated with 75 and 300 mg, 66.7% (2/3) and 33.3% (1/3) had detectable HIV-VL in CAPD, respectively. The peritoneal membrane characteristics and CAPD system strengths were variable across the entire study population. Lamivudine exposure was increased in blood serum (50 mg-AUC0-24 h, 651.3 ng/mL; 75 mg-AUC0-24 h, 677.84 ng/mL; 300 mg-AUC0-24 h, 3135.89 ng/mL) compared to CAPD effluents (50 mg-AUC0-24 h, 384.91 ng/mL; 75 mg-AUC0-24 h, 383.24 ng/mL; 300 mg-AUC0-24 h, 2001.60 ng/mL) among the entire study population. The Cmax (50 mg, 41.5 ng/mL; 75 mg, 53.2 ng/mL; 300 mg, 199.1 ng/mL) and Cmin (50 mg, 17.8 ng/mL; 75 mg, 16.4 ng/mL; 300 mg, 76.4 ng/mL) measured in serum were within the therapeutic levels. CONCLUSIONS: Steady-state lamivudine pharmacokinetic measures were variable among the entire study population. However, the total lamivudine exposure was within the therapeutic levels.
Asunto(s)
Infecciones por VIH , VIH-1 , Fallo Renal Crónico , Lamivudine , Diálisis Peritoneal , Humanos , Lamivudine/farmacocinética , Lamivudine/uso terapéutico , Lamivudine/administración & dosificación , Masculino , Persona de Mediana Edad , Femenino , VIH-1/efectos de los fármacos , Fallo Renal Crónico/terapia , Adulto , Infecciones por VIH/tratamiento farmacológico , ARN Viral/sangre , Fármacos Anti-VIH/farmacocinética , Fármacos Anti-VIH/uso terapéutico , Fármacos Anti-VIH/sangre , Fármacos Anti-VIH/administración & dosificación , Carga ViralRESUMEN
Genetic variation within the HLA-B locus has the strongest impact on HIV disease progression of any polymorphisms within the human genome. However, identifying the exact mechanism involved is complicated by several factors. HLA-Bw4 alleles provide ligands for NK cells and for CD8 T cells, and strong linkage disequilibrium between HLA class I alleles complicates the discrimination of individual HLA allelic effects from those of other HLA and non-HLA alleles on the same haplotype. Here, we exploit an experiment of nature involving two recently diverged HLA alleles, HLA-B*42:01 and HLA-B*42:02, which differ by only a single amino acid. Crucially, they occur primarily on identical HLA class I haplotypes and, as Bw6 alleles, do not act as NK cell ligands and are therefore largely unconfounded by other genetic factors. We show that in an outbred cohort (n = 2,093) of HIV C-clade-infected individuals, a single amino acid change at position 9 of the HLA-B molecule critically affects peptide binding and significantly alters the cytotoxic T lymphocyte (CTL) epitopes targeted, measured directly ex vivo by gamma interferon (IFN-γ) enzyme-linked immunospot (ELISPOT) assay (P = 2 × 10(-10)) and functionally through CTL escape mutation (P = 2 × 10(-8)). HLA-B*42:01, which presents multiple Gag epitopes, is associated with a 0.52 log(10) lower viral-load set point than HLA-B*42:02 (P = 0.02), which presents no p24 Gag epitopes. The magnitude of this effect from a single amino acid difference in the HLA-A*30:01/B*42/Cw*17:01 haplotype is equivalent to 75% of that of HLA-B*57:03, the most protective HLA class I allele in this population. This naturally controlled experiment represents perhaps the clearest demonstration of the direct impact of a particular HIV-specific CTL on disease control.
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Resistencia a la Enfermedad , Infecciones por VIH/inmunología , Antígeno HLA-B27/genética , Antígeno HLA-B27/inmunología , Polimorfismo de Nucleótido Simple , Adulto , Alelos , Infecciones por VIH/virología , VIH-1/aislamiento & purificación , Humanos , Carga ViralRESUMEN
The potential contribution of HLA-A alleles to viremic control in chronic HIV type 1 (HIV-1) infection has been relatively understudied compared with HLA-B. In these studies, we show that HLA-A*7401 is associated with favorable viremic control in extended southern African cohorts of >2100 C-clade-infected subjects. We present evidence that HLA-A*7401 operates an effect that is independent of HLA-B*5703, with which it is in linkage disequilibrium in some populations, to mediate lowered viremia. We describe a novel statistical approach to detecting additive effects between class I alleles in control of HIV-1 disease, highlighting improved viremic control in subjects with HLA-A*7401 combined with HLA-B*57. In common with HLA-B alleles that are associated with effective control of viremia, HLA-A*7401 presents highly targeted epitopes in several proteins, including Gag, Pol, Rev, and Nef, of which the Gag epitopes appear immunodominant. We identify eight novel putative HLA-A*7401-restricted epitopes, of which three have been defined to the optimal epitope. In common with HLA-B alleles linked with slow progression, viremic control through an HLA-A*7401-restricted response appears to be associated with the selection of escape mutants within Gag epitopes that reduce viral replicative capacity. These studies highlight the potentially important contribution of an HLA-A allele to immune control of HIV infection, which may have been concealed by a stronger effect mediated by an HLA-B allele with which it is in linkage disequilibrium. In addition, these studies identify a factor contributing to different HIV disease outcomes in individuals expressing HLA-B*5703.
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Infecciones por VIH/inmunología , VIH-1/inmunología , Antígenos HLA-A/genética , Antígenos HLA-B/genética , Viremia/inmunología , África , Alelos , Recuento de Linfocito CD4 , Linfocitos T CD8-positivos/inmunología , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Femenino , Citometría de Flujo , Infecciones por VIH/genética , Infecciones por VIH/virología , VIH-1/genética , Antígenos HLA-A/inmunología , Antígenos HLA-B/inmunología , Humanos , Desequilibrio de Ligamiento , Datos de Secuencia Molecular , Análisis de Secuencia de Proteína , Carga Viral , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen pol del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen rev del Virus de la Inmunodeficiencia Humana/inmunologíaRESUMEN
High profile international goals have been set for the elimination of hepatitis B virus (HBV) infection as a public health threat by the year 2030. Developing and expanding equitable, accessible translational HBV research programmes that represent real-world populations are therefore an urgent priority for clinical and academic communities. We present experiences and insights by an expert interdisciplinary group focusing on barriers that impede adults living with HBV infection from participating in clinical studies. Our viewpoint describes barriers we have identified through working in a variety of settings across South Africa, including lack of education and awareness, experiences of stigma and discrimination, challenges for governance and data management, and a burden of complex morbidity. Through identifying these challenges, we propose solutions and interventions, highlight new approaches, and provide a framework for future research.
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Aim: The aim of this study was to investigate the utility of serological tests for the diagnosis of COVID-19 during the first week of symptom onset in patients confirmed with the real-time RT-PCR. Materials & methods: A systematic review and meta-analysis of 58 publications were performed using data obtained from Academic Search Ultimate, Africa-wide, Scopus, Web of Science and MEDLINE. Results: We found that the highest pooled sensitivities were obtained with ELISA IgM-IgG and chemiluminescence immunoassay IgM tests. Conclusion: Serological tests have low sensitivity within the first week of symptom onset and cannot replace nucleic acid amplification tests. However, serological assays can be used to support nucleic acid amplification tests.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread across the globe at unprecedented speed and is showing no signs of slowing down. The outbreak of coronavirus disease 2019 (COVID-19) has led to significant health burden in infected patients especially in those with underlying comorbidities. The aim of this study was to evaluate the correlation between comorbidities and their role in the exacerbation of disease in COVID-19 patients leading to fatal outcomes. A systematic review was conducted using data from MEDLINE, Scopus, Web of Science, and EMBASE databases published from 1 December 2019 to 15 September 2020. Fifty-three articles were included in the systematic review. Of those 53 articles, 8 articles were eligible for meta-analysis. Hypertension, obesity, and diabetes mellitus were identified to be the most prevalent comorbidities in COVID-19 patients. Our meta-analysis showed that cancer, chronic kidney diseases, diabetes mellitus, and hypertension were independently associated with mortality in COVID-19 patients. Chronic kidney disease was statistically the most prominent comorbidity leading to death. However, despite having high prevalence, obesity was not associated with mortality in COVID-19 patients.IMPORTANCE COVID-19 has plagued the world since it was first identified in December 2019. Previous systematic reviews and meta-analysis were limited by various factors such as the usage of non-peer reviewed data and were also limited by the lack of clinical data on a global scale. Comorbidities are frequently cited as risk factors for severe COVID-19 outcomes. However, the degree to which specific comorbidities impact the disease is debatable. Our study selection involves a global reach and covers all comorbidities that were reported to be involved in the exacerbation of COVID-19 leading to fatal outcomes, which allows us to identify the specific comorbidities that have higher risk in patients. The study highlights COVID-19 high-risk groups. However, further research should focus on the status of comorbidities and prognosis in COVID-19 patients.