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1.
Annu Rev Immunol ; 40: 589-614, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35130029

RESUMO

Pulmonary granulomas are widely considered the epicenters of the immune response to Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Recent animal studies have revealed factors that either promote or restrict TB immunity within granulomas. These models, however, typically ignore the impact of preexisting immunity on cellular organization and function, an important consideration because most TB probably occurs through reinfection of previously exposed individuals. Human postmortem research from the pre-antibiotic era showed that infections in Mtb-naïve individuals (primary TB) versus those with prior Mtb exposure (postprimary TB) have distinct pathologic features. We review recent animal findings in TB granuloma biology, which largely reflect primary TB. We also discuss our current understanding of postprimary TB lesions, about which much less is known. Many knowledge gaps remain, particularly regarding how preexisting immunity shapes granuloma structure and local immune responses at Mtb infection sites.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Animais , Granuloma/etiologia , Humanos , Pulmão/microbiologia , Pulmão/patologia
2.
Cell ; 185(20): 3720-3738.e13, 2022 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-36103894

RESUMO

Necrosis of macrophages in the granuloma, the hallmark immunological structure of tuberculosis, is a major pathogenic event that increases host susceptibility. Through a zebrafish forward genetic screen, we identified the mTOR kinase, a master regulator of metabolism, as an early host resistance factor in tuberculosis. We found that mTOR complex 1 protects macrophages from mycobacterium-induced death by enabling infection-induced increases in mitochondrial energy metabolism fueled by glycolysis. These metabolic adaptations are required to prevent mitochondrial damage and death caused by the secreted mycobacterial virulence determinant ESAT-6. Thus, the host can effectively counter this early critical mycobacterial virulence mechanism simply by regulating energy metabolism, thereby allowing pathogen-specific immune mechanisms time to develop. Our findings may explain why Mycobacterium tuberculosis, albeit humanity's most lethal pathogen, is successful in only a minority of infected individuals.


Assuntos
Mycobacterium marinum , Mycobacterium tuberculosis , Tuberculose , Animais , Mycobacterium tuberculosis/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Peixe-Zebra
3.
Immunity ; 55(2): 272-289.e7, 2022 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-35081372

RESUMO

T follicular helper (Tfh) cells are defined by a Bcl6+CXCR5hiPD-1hi phenotype, but only a minor fraction of these reside in germinal centers (GCs). Here, we examined whether GC-resident and -nonresident Tfh cells share a common physiology and function. Fluorescently labeled, GC-resident Tfh cells in different mouse models were distinguished by low expression of CD90. CD90neg/lo GCTfh cells required antigen-specific, MHCII+ B cells to develop and stopped proliferating soon after differentiation. In contrast, nonresident, CD90hi Tfh (GCTfh-like) cells developed normally in the absence of MHCII+ B cells and proliferated continuously during primary responses. The TCR repertoires of both Tfh subsets overlapped initially but later diverged in association with dendritic cell-dependent proliferation of CD90hi GCTfh-like cells, suggestive of TCR-dependency seen also in TCR-transgenic adoptive transfer experiments. Furthermore, the transcriptomes of CD90neg/lo and CD90hi GCTfh-like cells were enriched in different functional pathways. Thus, GC-resident and nonresident Tfh cells have distinct developmental requirements and activities, implying distinct functions.


Assuntos
Centro Germinativo/imunologia , Receptor de Morte Celular Programada 1/metabolismo , Receptores CXCR5/metabolismo , Células T Auxiliares Foliculares/metabolismo , Subpopulações de Linfócitos T/metabolismo , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Comunicação Celular/imunologia , Diferenciação Celular , Proliferação de Células , Células Dendríticas/imunologia , Perfilação da Expressão Gênica , Antígenos de Histocompatibilidade Classe II/metabolismo , Camundongos , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Esfingosina-1-Fosfato/metabolismo , Células T Auxiliares Foliculares/imunologia , Subpopulações de Linfócitos T/imunologia , Antígenos Thy-1/metabolismo
4.
Immunity ; 54(10): 2245-2255.e4, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34464595

RESUMO

BCL6 is required for development of follicular T helper (Tfh) cells to support germinal center (GC) formation. However, it is not clear what unique functions programmed by BCL6 can explain its absolute essentiality in T cells for GC formation. We found that ablation of one Bcl6 allele did not appreciably alter early T cell activation and follicular localization but inhibited GC formation and Tfh cell maintenance. BCL6 impinged on Tfh calcium signaling and also controlled Tfh entanglement with and CD40L delivery to B cells. Amounts of BCL6 protein and nominal frequencies of Tfh cells markedly changed within hours after strengths of T-B cell interactions were altered in vivo, while CD40L overexpression rectified both defective GC formation and Tfh cell maintenance because of the BCL6 haploinsufficiency. Our results reveal BCL6 functions in Tfh cells that are essential for GC formation and suggest that BCL6 helps maintain Tfh cell phenotypes in a T cell non-autonomous manner.


Assuntos
Linfócitos B/imunologia , Centro Germinativo/imunologia , Ativação Linfocitária/imunologia , Proteínas Proto-Oncogênicas c-bcl-6/imunologia , Células T Auxiliares Foliculares/imunologia , Animais , Camundongos
5.
Semin Immunol ; 65: 101672, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36469987

RESUMO

Treatment of tuberculosis (TB) involves the administration of anti-mycobacterial drugs for several months. The emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb, the causative agent) together with increased disease severity in people with co-morbidities such as diabetes mellitus and HIV have hampered efforts to reduce case fatality. In severe disease, TB pathology is largely attributable to over-exuberant host immune responses targeted at controlling bacterial replication. Non-resolving inflammation driven by host pro-inflammatory mediators in response to high bacterial load leads to pulmonary pathology including cavitation and fibrosis. The need to improve clinical outcomes and reduce treatment times has led to a two-pronged approach involving the development of novel antimicrobials as well as host-directed therapies (HDT) that favourably modulate immune responses to Mtb. HDT strategies incorporate aspects of immune modulation aimed at downregulating non-productive inflammatory responses and augmenting antimicrobial effector mechanisms to minimise pulmonary pathology and accelerate symptom resolution. HDT in combination with existing antimycobacterial agents offers a potentially promising strategy to improve the long-term outcome for TB patients. In this review, we describe components of the host immune response that contribute to inflammation and tissue damage in pulmonary TB, including cytokines, matrix metalloproteinases, lipid mediators, and neutrophil extracellular traps. We then proceed to review HDT directed at these pathways.


Assuntos
Mycobacterium tuberculosis , Tuberculose Pulmonar , Tuberculose , Humanos , Antituberculosos/uso terapêutico , Tuberculose Pulmonar/tratamento farmacológico , Inflamação
6.
Proc Natl Acad Sci U S A ; 121(44): e2412653121, 2024 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-39441632

RESUMO

EfpA, the first major facilitator superfamily (MFS) protein identified in Mycobacterium tuberculosis (Mtb), is an essential efflux pump implicated in resistance to multiple drugs. EfpA-inhibitors have been developed to kill drug-tolerant Mtb. However, the biological function of EfpA has not yet been elucidated. Here, we present the cryo-EM structures of EfpA complexed with lipids or the inhibitor BRD-8000.3 at resolutions of 2.9 Å and 3.4 Å, respectively. Unexpectedly, EfpA forms an antiparallel dimer. Functional studies reveal that EfpA is a lipid transporter and BRD-8000.3 inhibits its lipid transport activity. Intriguingly, the mutation V319F, known to confer resistance to BRD-8000.3, alters the expression level and oligomeric state of EfpA. Based on our results and the observation of other antiparallel dimers in the MFS family, we propose an antiparallel-function model of EfpA. Collectively, our work provides structural and functional insights into EfpA's role in lipid transport and drug resistance, which would accelerate the development of antibiotics against this promising drug target.


Assuntos
Proteínas de Bactérias , Microscopia Crioeletrônica , Mycobacterium tuberculosis , Mycobacterium tuberculosis/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/genética , Modelos Moleculares , Transporte Biológico
7.
Annu Rev Med ; 75: 177-188, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-37983385

RESUMO

Recent advances in the treatment of tuberculosis (TB) have led to improvements unprecedented in our lifetime. Decades of research in developing new drugs, especially for multidrug-resistant TB, have created not only multiple new antituberculous agents but also a new approach to development and treatment, with a focus on maximizing the benefit to the individual patient. Prevention of TB disease has also been improved and recognized as a critical component of global TB control. While the momentum is positive, it will take continued investment at all levels, especially training of new dedicated TB researchers and advocates around the world, to maintain this progress.


Assuntos
Tuberculose Resistente a Múltiplos Medicamentos , Humanos , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/prevenção & controle
8.
Mol Cell ; 72(2): 263-274.e5, 2018 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-30244835

RESUMO

Antibiotic-resistant bacterial pathogens pose an urgent healthcare threat, prompting a demand for new medicines. We report the mode of action of the natural ansamycin antibiotic kanglemycin A (KglA). KglA binds bacterial RNA polymerase at the rifampicin-binding pocket but maintains potency against RNA polymerases containing rifampicin-resistant mutations. KglA has antibiotic activity against rifampicin-resistant Gram-positive bacteria and multidrug-resistant Mycobacterium tuberculosis (MDR-M. tuberculosis). The X-ray crystal structures of KglA with the Escherichia coli RNA polymerase holoenzyme and Thermus thermophilus RNA polymerase-promoter complex reveal an altered-compared with rifampicin-conformation of KglA within the rifampicin-binding pocket. Unique deoxysugar and succinate ansa bridge substituents make additional contacts with a separate, hydrophobic pocket of RNA polymerase and preclude the formation of initial dinucleotides, respectively. Previous ansa-chain modifications in the rifamycin series have proven unsuccessful. Thus, KglA represents a key starting point for the development of a new class of ansa-chain derivatized ansamycins to tackle rifampicin resistance.


Assuntos
Produtos Biológicos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Rifabutina/farmacologia , Rifampina/farmacologia , Rifamicinas/farmacologia , Antituberculosos/farmacologia , RNA Polimerases Dirigidas por DNA/genética , Farmacorresistência Bacteriana/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Humanos , Testes de Sensibilidade Microbiana/métodos , Mutação/efeitos dos fármacos , Mutação/genética , Mycobacterium tuberculosis/genética , Thermus thermophilus/efeitos dos fármacos , Thermus thermophilus/genética
9.
Trends Immunol ; 43(8): 640-656, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35842266

RESUMO

Tuberculosis (TB), the world's deadliest bacterial infection, afflicts more human males than females, with a male/female (M/F) ratio of 1.7. Sex disparities in TB prevalence, pathophysiology, and clinical manifestations are widely reported, but the underlying biological mechanisms remain largely undefined. This review assesses epidemiological data on sex disparity in TB, as well as possible underlying hormonal and genetic mechanisms that might differentially modulate innate and adaptive immune responses in males and females, leading to sex differences in disease susceptibility. We consider whether this sex disparity can be extended to the efficacy of vaccines and discuss novel animal models which may offer mechanistic insights. A better understanding of the biological factors underpinning sex-related immune responses in TB may enable sex-specific personalized therapies for TB.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Animais , Suscetibilidade a Doenças , Feminino , Humanos , Imunidade , Masculino , Tuberculose/genética
10.
Brain ; 147(9): 3247-3260, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-38442687

RESUMO

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), remains a global health burden. While M. tuberculosis is primarily a respiratory pathogen, it can spread to other organs, including the brain and meninges, causing TB meningitis (TBM). However, little is known about the immunological mechanisms that lead to differential disease across organs. Attention has focused on differences in T cell responses in the control of M. tuberculosis in the lungs, but emerging data point to a role for antibodies, as both biomarkers of disease control and as antimicrobial molecules. Given an increasing appreciation for compartmentalized antibody responses across the blood-brain barrier, here we characterized the antibody profiles across the blood and brain compartments in TBM and determined whether M. tuberculosis-specific humoral immune responses differed between M. tuberculosis infection of the lung (pulmonary TB) and TBM. Using a high throughput systems serology approach, we deeply profiled the antibody responses against 10 different M. tuberculosis antigens, including lipoarabinomannan (LAM) and purified protein derivative (PPD), in HIV-negative adults with pulmonary TB (n = 10) versus TBM (n = 60). Antibody studies included analysis of immunoglobulin isotypes (IgG, IgM, IgA) and subclass levels (IgG1-4) and the capacity of M. tuberculosis-specific antibodies to bind to Fc receptors or C1q and to activate innate immune effector functions (complement and natural killer cell activation; monocyte or neutrophil phagocytosis). Machine learning methods were applied to characterize serum and CSF responses in TBM, identify prognostic factors associated with disease severity, and define the key antibody features that distinguish TBM from pulmonary TB. In individuals with TBM, we identified CSF-specific antibody profiles that marked a unique and compartmentalized humoral response against M. tuberculosis, characterized by an enrichment of M. tuberculosis-specific antibodies able to robustly activate complement and drive phagocytosis by monocytes and neutrophils, all of which were associated with milder TBM severity at presentation. Moreover, individuals with TBM exhibited M. tuberculosis-specific antibodies in the serum with an increased capacity to activate phagocytosis by monocytes, compared with individuals with pulmonary TB, despite having lower IgG titres and Fcγ receptor-binding capacity. Collectively, these data point to functionally divergent humoral responses depending on the site of infection (i.e. lungs versus brain) and demonstrate a highly compartmentalized M. tuberculosis-specific antibody response within the CSF in TBM. Moreover, our results suggest that phagocytosis- and complement-mediating antibodies may promote attenuated neuropathology and milder TBM disease.


Assuntos
Mycobacterium tuberculosis , Tuberculose Meníngea , Tuberculose Pulmonar , Humanos , Mycobacterium tuberculosis/imunologia , Masculino , Adulto , Feminino , Tuberculose Meníngea/imunologia , Tuberculose Pulmonar/imunologia , Pessoa de Meia-Idade , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Anticorpos Antibacterianos/líquido cefalorraquidiano , Encéfalo/imunologia , Adulto Jovem
11.
Clin Microbiol Rev ; 36(4): e0008823, 2023 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-38032192

RESUMO

Tuberculosis (TB) is a major global health problem and the second most prevalent infectious killer after COVID-19. It is caused by Mycobacterium tuberculosis (Mtb) and has become increasingly challenging to treat due to drug resistance. The World Health Organization declared TB a global health emergency in 1993. Drug resistance in TB is driven by mutations in the bacterial genome that can be influenced by prolonged drug exposure and poor patient adherence. The development of drug-resistant forms of TB, such as multidrug resistant, extensively drug resistant, and totally drug resistant, poses significant therapeutic challenges. Researchers are exploring new drugs and novel drug delivery systems, such as nanotechnology-based therapies, to combat drug resistance. Nanodrug delivery offers targeted and precise drug delivery, improves treatment efficacy, and reduces adverse effects. Along with nanoscale drug delivery, a new generation of antibiotics with potent therapeutic efficacy, drug repurposing, and new treatment regimens (combinations) that can tackle the problem of drug resistance in a shorter duration could be promising therapies in clinical settings. However, the clinical translation of nanomedicines faces challenges such as safety, large-scale production, regulatory frameworks, and intellectual property issues. In this review, we present the current status, most recent findings, challenges, and limiting barriers to the use of emulsions and nanoparticles against drug-resistant TB.


Assuntos
Mycobacterium tuberculosis , Nanopartículas , Tuberculose Resistente a Múltiplos Medicamentos , Humanos , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Preparações Farmacêuticas , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Sistemas de Liberação de Medicamentos
12.
Immunol Rev ; 301(1): 98-121, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33955564

RESUMO

BCG turns 100 this year and while it might not be the perfect vaccine, it has certainly contributed significantly towards eradication and prevention of spread of tuberculosis (TB). The search for newer and better vaccines for TB is an ongoing endeavor and latest results from trials of candidate TB vaccines such as M72AS01 look promising. However, recent encouraging data from BCG revaccination trials in adults combined with studies on mucosal and intravenous routes of BCG vaccination in non-human primate models have renewed interest in BCG for TB prevention. In addition, several well-demonstrated non-specific effects of BCG, for example, prevention of viral and respiratory infections, give BCG an added advantage. Also, BCG vaccination is currently being widely tested in human clinical trials to determine whether it protects against SARS-CoV-2 infection and/or death with detailed analyses and outcomes from several ongoing trials across the world awaited. Through this review, we attempt to bring together information on various aspects of the BCG-induced immune response, its efficacy in TB control, comparison with other candidate TB vaccines and strategies to improve its efficiency including revaccination and alternate routes of administration. Finally, we discuss the future relevance of BCG use especially in light of its several heterologous benefits.


Assuntos
Vacina BCG/imunologia , Mycobacterium tuberculosis/imunologia , Tuberculose/imunologia , Tuberculose/prevenção & controle , Vacinação , Imunidade Adaptativa , Vacina BCG/administração & dosagem , Humanos , Imunidade Heteróloga , Imunidade Inata , Imunogenicidade da Vacina , Memória Imunológica
13.
Immunol Rev ; 301(1): 10-29, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33751597

RESUMO

Tuberculosis is a significant health problem without an effective vaccine to combat it. A thorough understanding of the immune response and correlates of protection is needed to develop a more efficient vaccine. The immune response against Mycobacterium tuberculosis (Mtb) is complex and involves all aspects of the immune system, however, the optimal protective, non-pathogenic T cell response against Mtb is still elusive. This review will focus on discussing CD4 T cell immunity against mycobacteria and its importance in Mtb infection with a primary focus on human studies. We will in particular discuss the large heterogeneity of immune cell subsets that have been revealed by recent immunological investigations at an unprecedented level of detail. These studies have identified specific classical CD4 T cell subsets important for immune responses against Mtb in various states of infection. We further discuss the functional attributes that have been linked to the various subsets such as upregulation of activation markers and cytokine production. Another important topic to be considered is the antigenic targets of Mtb-specific immune responses, and how antigen reactivity is influenced by both disease state and environmental exposure(s). These are key points for both vaccines and immune diagnostics development. Ultimately, these factors are holistically considered in the definition and investigations of what are the correlates on protection and resolution of disease.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Antígenos de Bactérias , Linfócitos T CD4-Positivos , Humanos , Imunidade , Subpopulações de Linfócitos T
14.
J Infect Dis ; 229(3): 813-823, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38262629

RESUMO

BACKGROUND: Tuberculosis (TB) treatment-related adverse drug reactions (TB-ADRs) can negatively affect adherence and treatment success rates. METHODS: We developed prediction models for TB-ADRs, considering participants with drug-susceptible pulmonary TB who initiated standard TB therapy. TB-ADRs were determined by the physician attending the participant, assessing causality to TB drugs, the affected organ system, and grade. Potential baseline predictors of TB-ADR included concomitant medication (CM) use, human immunodeficiency virus (HIV) status, glycated hemoglobin (HbA1c), age, body mass index (BMI), sex, substance use, and TB drug metabolism variables (NAT2 acetylator profiles). The models were developed through bootstrapped backward selection. Cox regression was used to evaluate TB-ADR risk. RESULTS: There were 156 TB-ADRs among 102 of the 945 (11%) participants included. Most TB-ADRs were hepatic (n = 82 [53%]), of moderate severity (grade 2; n = 121 [78%]), and occurred in NAT2 slow acetylators (n = 62 [61%]). The main prediction model included CM use, HbA1c, alcohol use, HIV seropositivity, BMI, and age, with robust performance (c-statistic = 0.79 [95% confidence interval {CI}, .74-.83) and fit (optimism-corrected slope and intercept of -0.09 and 0.94, respectively). An alternative model replacing BMI with NAT2 had similar performance. HIV seropositivity (hazard ratio [HR], 2.68 [95% CI, 1.75-4.09]) and CM use (HR, 5.26 [95% CI, 2.63-10.52]) increased TB-ADR risk. CONCLUSIONS: The models, with clinical variables and with NAT2, were highly predictive of TB-ADRs.


Assuntos
Arilamina N-Acetiltransferase , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Soropositividade para HIV , Tuberculose Pulmonar , Humanos , Antituberculosos/efeitos adversos , Brasil/epidemiologia , Hemoglobinas Glicadas , Soropositividade para HIV/tratamento farmacológico , Tuberculose Pulmonar/tratamento farmacológico , Arilamina N-Acetiltransferase/metabolismo
15.
J Infect Dis ; 230(3): e524-e535, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-38412342

RESUMO

BACKGROUND: Coinfection of human immunodeficiency virus type 1 (HIV-1) is the most significant risk factor for tuberculosis (TB). The immune responses of the lung are essential to restrict the growth of Mycobacterium tuberculosis and avoid the emergence of the disease. Nevertheless, there is still limited knowledge about the local immune response in people with HIV-1-TB coinfection. METHODS: We employed single-cell RNA sequencing (scRNA-seq) on bronchoalveolar lavage fluid from 9 individuals with HIV-1-TB coinfection and 10 with pulmonary TB. RESULTS: A total of 19 058 cells were grouped into 4 major cell types: myeloid cells, T/natural killer (NK) cells, B cells, and epithelial cells. The myeloid cells and T/NK cells were further divided into 10 and 11 subsets, respectively. The proportions of dendritic cell subsets, CD4+ T cells, and NK cells were lower in the HIV-1-TB coinfection group compared to the TB group, while the frequency of CD8+ T cells was higher. Additionally, we identified numerous differentially expressed genes between the CD4+ and CD8+ T-cell subsets between the 2 groups. CONCLUSIONS: HIV-1 infection not only affects the abundance of immune cells in the lungs but also alters their functions in patients with pulmonary TB.


Assuntos
Líquido da Lavagem Broncoalveolar , Coinfecção , Infecções por HIV , HIV-1 , Análise de Célula Única , Tuberculose Pulmonar , Humanos , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/complicações , Infecções por HIV/complicações , Infecções por HIV/imunologia , Coinfecção/virologia , Coinfecção/imunologia , Coinfecção/microbiologia , HIV-1/imunologia , Masculino , Adulto , Líquido da Lavagem Broncoalveolar/microbiologia , Líquido da Lavagem Broncoalveolar/virologia , Líquido da Lavagem Broncoalveolar/imunologia , Feminino , Mycobacterium tuberculosis/imunologia , Pessoa de Meia-Idade , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Células Matadoras Naturais/imunologia , Pulmão/microbiologia , Pulmão/imunologia , Pulmão/virologia
16.
J Infect Dis ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38723117

RESUMO

BACKGROUND: The latent TB infection (LTBI) is an asymptomatic infection caused by Mycobacterium tuberculosis (M.bt). Previous studies have shown a host-protective role for Heme oxygenase-1 (HO-1) during Mtb infection and an important involvement of Glutathione peroxidase-4 (Gpx4) in the necrotic pathology of the disease. Furthermore, increasing evidence suggested a crucial role for Glutathione in the granulomatous response to M. tb infection, with altered GSH levels associated to decreased host resistance. The aim of this study was to provide additional tools for discriminating the pathologic TB state and the asymptomatic infection. METHODS: We analyzed the gene expression of HO-1 and Gpx4 enzymes in blood of subjects with LTBI, active TB and healthy controls, and we also measured blood levels of the reduced (GSH) and oxidized (GSSG) forms of glutathione, together with the evaluation of GCL expression, the gene responsible for the GSH de novo synthesis. RESULTS: Our findings highlight a shift of glutathione homeostasis towards a more reducing conditions in LTBI, and a different modulation of GSH-dependent genes and HO-1 expression respect to active TB. CONCLUSION: This study can provide useful tools to understand the redox background that address the infection toward the asymptomatic or active disease.

17.
Clin Infect Dis ; 2024 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-39378332

RESUMO

BACKGROUND: In countries with low tuberculosis (TB) burden, the risk of TB in people with HIV (PWH) once HIV virological suppression is achieved is not fully understood. METHODS: In a nationwide cohort, we included all adult PWH from the Danish HIV Cohort initiating antiretroviral therapy (ART) (1995-2017) without prior TB disease. We used Kaplan-Meier estimation and Poisson regression to calculate TB incidence rate (IR) after six months of ART, along with associated risk factors and mortality rates (MR). RESULTS: Among 6,849 PWH initiating ART (median follow-up 7.4 years), 84 developed TB (IR 1.4/1000 person-year [PY]), 54 of them beyond six months of ART initiation, IR 0.97/1000 PY (95%CI:1.17-1.79): 1.95 (95%CI:1.34-2.76) in non-Danish born, 0.36 (95%CI:0.21-0.62) in Danish-born without injection drug use (IDU), and 2.95 (95%CI:1.53-5.66) in Danish-born with IDU. Danish-born with suppressed viremia, and no IDU or known TB exposures had the lowest risk (IR 0.05/1000 PY).In the adjusted analysis, being non-Danish born (aIRR 4.27[95%CI:2.36-7.72]), IDU (aIRR 4.95[95%CI:2.55-9.62]), and previous AIDS-defining events (aIRR 2.05[95%CI:1.06-3.94]) raised TB risk, while suppressed HIV-RNA (aIRR 0.58[95%CI:0.34-0.99]) reduced it. The overall MR for HIV/TB co-infected post- ART was high, at 48.9/1000 PY (95%CI:30.4-78.7). CONCLUSIONS: The TB risk remains elevated in PWH beyond six months of ART initiation, especially among migrants, IDU, those without suppressed HIV-RNA, and individuals exposed to high TB endemic areas or with social risk determinants of health. Conversely, PWH without these risk factors have a TB risk similar to the general population and would not require targeted TB screening strategies.

18.
Clin Infect Dis ; 2024 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-38824440

RESUMO

Data on alcohol use and incident Tuberculosis (TB) infection are needed. In adults aged 15+ in rural Uganda (N=49,585), estimated risk of incident TB infection was 29.2% with alcohol use vs. 19.2% without (RR: 1.49; 95%CI: 1.40-1.60). There is potential for interventions to interrupt transmission among people who drink alcohol.

19.
Clin Infect Dis ; 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38170196

RESUMO

BACKGROUND: The Xpert® MTB/RIF rapid molecular test provides a quantitative measure of Mycobacterium tuberculosis (Mtb) DNA in the form of cycle threshold (Ct) values. This information can be translated into mycobacterial load and used as a potential risk measure of bacterial spread for tuberculosis cases, which can impact infection control. However, the role of Ct values in assessing Mtb transmission to close contacts has not yet been demonstrated. METHODS: A prospective study was performed to investigate the association between Xpert® MTB/RIF Ct values and Mtb transmission to close contacts of patients with culture-confirmed pulmonary TB in a multi-center Brazilian cohort. We evaluated clinical and laboratory data, such as age, sex, race, smoking habits, drug use, alcohol use, chest radiograph, Xpert® MTB/RIF results among pulmonary tuberculosis cases, and QuantiFERON(QFT)-Plus results at baseline and after six months for close contacts who had a negative result at baseline. RESULTS: A total of 1,055 close contacts of 382 pulmonary tuberculosis cases were included in the study. The median Ct values from pulmonary tuberculosis cases of QFT-Plus positive (at baseline or six months) close contacts were lower compared with those who were QFT-Plus negative. An adjusted logistic regression demonstrated that reduced Ct values from the index cases were independently associated with QFT-Plus conversion from negative to positive (OR: 1.61, 95% CI: 1.12-2.32) after adjusting for clinical characteristics. CONCLUSION: Close contacts of pulmonary TB index cases exhibiting low Xpert MTB/RIF Ct values displayed higher rates of TB infection, reflecting Mtb transmission.

20.
Clin Infect Dis ; 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38748183

RESUMO

BACKGROUND: People with HIV (PHIV) admitted to hospital have high mortality, with tuberculosis (TB) being the major cause of death. Systematic use of new TB diagnostics could improve TB diagnosis and might improve outcomes. METHODS: We conducted a cluster randomised trial among adult PHIV admitted to Zomba Central Hospital, Malawi. Admission-days were randomly assigned to: enhanced TB diagnostics using urine lipoarabinomannan (LAM) antigen tests (SILVAMP-LAM, Fujifilm, Japan and Determine-LAM, Alere/Abbot, USA), digital chest X-ray with computer aided diagnosis (dCXR-CAD, CAD4TBv6, Delft, Netherlands), plus usual care ("enhanced TB diagnostics"); or usual care alone ("usual care"). The primary outcome was TB treatment initiation during admission. Secondary outcomes were 56-day mortality, TB diagnosis within 24-hours, and undiagnosed TB at discharge, ascertained by culture of one admission sputum sample. FINDINGS: Between 2 September 2020 and 15 February 2022, we recruited 419 people. Four people were excluded post-recruitment, leaving 415 adults recruited during 207 randomly assigned admission-days in modified intention-to-treat analysis. At admission, 90.8% (377/415) were taking antiretroviral therapy (ART) with median (IQR) CD4 cell count 240 cells/mm3. In the enhanced diagnostic arm, median CAD4TBv6 score was 60 (IQR: 51-71), 4.4% (9/207) had SILVAMP-LAM-positive and 14.4% (29/201) had Determine-LAM positive urine with three samples positive by both urine tests. TB treatment was initiated in 46/208 (22%) in enhanced TB diagnostics arm and 24/207 (12%) in usual care arm (risk ratio [RR] 1.92, 95% CI 1.20-3.08). There was no difference in mortality by 56 days (enhanced TB diagnosis: 54/208, 26%; usual care: 52/207, 25%; hazard ratio 1.05, 95% CI 0.72-1.53); TB treatment initiation within 24 hours (enhanced TB diagnosis: 8/207, 3.9%; usual care: 5/208, 2.4%; RR 1.61, 95% CI 0.53-4.71); or undiagnosed microbiological-confirmed TB at discharge (enhanced TB diagnosis, 0/207 (0.0%), usual care arm 2/208 (1.0%) (p = 0.50). INTERPRETATION: Urine SILVAMP-LAM/Determine-LAM plus dCXR-CAD diagnostics identified more hospitalised PHIV with TB than usual care. The increase in TB treatment appeared mainly due to greater use of Determine-LAM, rather than SILVAMP-LAM or dCXR-CAD. Poor concordance between Determine-LAM and SILVAMP-LAM urine tests requires further investigation. Inpatient mortality for adults with HIV remains unacceptability high.

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