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Sweeney S, Fielding K, Liu X, Thompson JA, Dong H, Jiang S, Zhao Y, Huan S, Vassall A. Unit costs and cost-effectiveness of a device to improve TB treatment adherence in China. IJTLD OPEN 2024; 1:299-305. [PMID: 39035432 PMCID: PMC11257087 DOI: 10.5588/ijtldopen.23.0451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 05/27/2024] [Indexed: 07/23/2024]
Abstract
BACKGROUND Adherence to TB drugs is crucial for improving treatment outcomes. Digital adherence technologies can improve adherence; however, there is a lack of evidence on cost-effectiveness. This study aimed to explore the cost-effectiveness of medication event reminder monitors (MERM) in China compared with the standard of care, using results from a pragmatic, cluster-randomised superiority trial of an electronic MERM in China. METHODS We collected primary unit cost data from the societal perspective, both at and above the health facility level. We estimated the incremental cost-effectiveness of MERM using a Markov model with a 20-year time horizon; a 3% discount rate was applied to costs and outcomes. We explored uncertainty through a series of sensitivity and scenario analyses. RESULTS The incremental cost of MERM was $27.22 per patient. Probabilistic sensitivity analysis showed significant uncertainty about the intervention's cost-effectiveness. Changing assumptions around key parameters substantially affected our estimated incremental cost-effectiveness ratio. CONCLUSIONS Although the incremental cost of the MERM box was low, current evidence does not indicate that the intervention would be cost-effective. However, the intervention's cost-effectiveness could improve if implemented as part of a broader strategy, including enhanced patient management.
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Affiliation(s)
- S Sweeney
- London School of Hygiene & Tropical Medicine, London, UK
| | - K Fielding
- London School of Hygiene & Tropical Medicine, London, UK
| | - X Liu
- National Center for TB Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - J A Thompson
- London School of Hygiene & Tropical Medicine, London, UK
| | - H Dong
- PATH China Office, Beijing, China
| | - S Jiang
- National Center for TB Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Y Zhao
- National Center for TB Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - S Huan
- Bill & Melinda Gates Foundation China Office, Beijing, China
| | - A Vassall
- London School of Hygiene & Tropical Medicine, London, UK
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Kumar AKH, Kadam A, Karunaianantham R, Tamizhselvan M, Padmapriyadarsini C, Mohan A, Jeyadeepa B, Radhakrishnan A, Singh UB, Bapat S, Mane A, Kumar P, Mamulwar M, Bhavani PK, Haribabu H, Rath N, Guleria R, Khan AM, Menon J. Effect of Metformin on Plasma Exposure of Rifampicin, Isoniazid, and Pyrazinamide in Patients on Treatment for Pulmonary Tuberculosis. Ther Drug Monit 2024; 46:370-375. [PMID: 38019456 PMCID: PMC11078288 DOI: 10.1097/ftd.0000000000001149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 08/08/2023] [Indexed: 11/30/2023]
Abstract
BACKGROUND To evaluate the effect of metformin on the plasma levels of rifampicin, isoniazid, and pyrazinamide in patients with drug-sensitive pulmonary tuberculosis being treated with first-line antituberculosis treatment (ATT) and to assess the influence of gene polymorphisms on the metabolic pathway of metformin and plasma levels of antitubercular drugs. METHODS Nondiabetic adults aged 18-60 years with pulmonary tuberculosis were randomized to either the standard ATT (ATT group) or ATT plus metformin (METRIF group) groups in a phase IIB clinical trial. An intensive pharmacokinetic study with blood collection at 0 hour (predosing), followed by 1, 2, 4, 6, 8, and 12 hours after dosing was conducted during the first month of treatment in a subset of 60 study participants after a minimum of 14 doses. Plasma concentrations of rifampicin, isoniazid, pyrazinamide, and metformin were measured by high-performance liquid chromatography using validated methods, and pharmacokinetic parameters and OCT1 and MATE1 gene polymorphisms were compared between the groups. RESULTS Significant increases in the clearance of rifampicin, isoniazid, and pyrazinamide were observed in patients in the METRIF group (n = 29) compared with those in the ATT group (n = 31). The AA genotypes of the single-nucleotide polymorphism of rs2289669 ( MATE1 ) in the METRIF group showed a significantly decreased area under the concentration-time curve to the last observation point and increased clearance of rifampicin. CONCLUSIONS Metformin altered rifampicin and isoniazid plasma concentrations in patients receiving antituberculosis treatment for pulmonary tuberculosis with little effect on sputum conversion at the end of treatment. Studies with larger sample sizes are needed to understand host drug-drug interactions.
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Affiliation(s)
| | | | | | | | | | - Anant Mohan
- All India Institute of Medical Sciences, New Delhi
| | - B. Jeyadeepa
- ICMR-National Institute for Research in Tuberculosis, Chennai
| | | | | | | | - Aarti Mane
- ICMR-National AIDS Research Institute, Pune
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Fuller NM, McQuaid CF, Harker MJ, Weerasuriya CK, McHugh TD, Knight GM. Mathematical models of drug-resistant tuberculosis lack bacterial heterogeneity: A systematic review. PLoS Pathog 2024; 20:e1011574. [PMID: 38598556 PMCID: PMC11060536 DOI: 10.1371/journal.ppat.1011574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 04/30/2024] [Accepted: 03/25/2024] [Indexed: 04/12/2024] Open
Abstract
Drug-resistant tuberculosis (DR-TB) threatens progress in the control of TB. Mathematical models are increasingly being used to guide public health decisions on managing both antimicrobial resistance (AMR) and TB. It is important to consider bacterial heterogeneity in models as it can have consequences for predictions of resistance prevalence, which may affect decision-making. We conducted a systematic review of published mathematical models to determine the modelling landscape and to explore methods for including bacterial heterogeneity. Our first objective was to identify and analyse the general characteristics of mathematical models of DR-mycobacteria, including M. tuberculosis. The second objective was to analyse methods of including bacterial heterogeneity in these models. We had different definitions of heterogeneity depending on the model level. For between-host models of mycobacterium, heterogeneity was defined as any model where bacteria of the same resistance level were further differentiated. For bacterial population models, heterogeneity was defined as having multiple distinct resistant populations. The search was conducted following PRISMA guidelines in five databases, with studies included if they were mechanistic or simulation models of DR-mycobacteria. We identified 195 studies modelling DR-mycobacteria, with most being dynamic transmission models of non-treatment intervention impact in M. tuberculosis (n = 58). Studies were set in a limited number of specific countries, and 44% of models (n = 85) included only a single level of "multidrug-resistance (MDR)". Only 23 models (8 between-host) included any bacterial heterogeneity. Most of these also captured multiple antibiotic-resistant classes (n = 17), but six models included heterogeneity in bacterial populations resistant to a single antibiotic. Heterogeneity was usually represented by different fitness values for bacteria resistant to the same antibiotic (61%, n = 14). A large and growing body of mathematical models of DR-mycobacterium is being used to explore intervention impact to support policy as well as theoretical explorations of resistance dynamics. However, the majority lack bacterial heterogeneity, suggesting that important evolutionary effects may be missed.
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Affiliation(s)
- Naomi M. Fuller
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher F. McQuaid
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Martin J. Harker
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Chathika K. Weerasuriya
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Timothy D. McHugh
- UCL Centre for Clinical Microbiology, Division of Infection & Immunity, Royal Free Campus, University College London, London, United Kingdom
| | - Gwenan M. Knight
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Antimicrobial Resistance Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Tuberculosis Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Martinecz A, Boeree MJ, Diacon AH, Dawson R, Hemez C, Aarnoutse RE, Abel Zur Wiesch P. High rifampicin peak plasma concentrations accelerate the slow phase of bacterial decline in tuberculosis patients: Evidence for heteroresistance. PLoS Comput Biol 2023; 19:e1011000. [PMID: 37053266 PMCID: PMC10128972 DOI: 10.1371/journal.pcbi.1011000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/25/2023] [Accepted: 03/06/2023] [Indexed: 04/15/2023] Open
Abstract
BACKGROUND Antibiotic treatments are often associated with a late slowdown in bacterial killing. This separates the killing of bacteria into at least two distinct phases: a quick phase followed by a slower phase, the latter of which is linked to treatment success. Current mechanistic explanations for the in vitro slowdown are either antibiotic persistence or heteroresistance. Persistence is defined as the switching back and forth between susceptible and non-susceptible states, while heteroresistance is defined as the coexistence of bacteria with heterogeneous susceptibilities. Both are also thought to cause a slowdown in the decline of bacterial populations in patients and therefore complicate and prolong antibiotic treatments. Reduced bacterial death rates over time are also observed within tuberculosis patients, yet the mechanistic reasons for this are unknown and therefore the strategies to mitigate them are also unknown. METHODS AND FINDINGS We analyse a dose ranging trial for rifampicin in tuberculosis patients and show that there is a slowdown in the decline of bacteria. We show that the late phase of bacterial killing depends more on the peak drug concentrations than the total drug exposure. We compare these to pharmacokinetic-pharmacodynamic models of rifampicin heteroresistance and persistence. We find that the observation on the slow phase's dependence on pharmacokinetic measures, specifically peak concentrations are only compatible with models of heteroresistance and incompatible with models of persistence. The quantitative agreement between heteroresistance models and observations is very good ([Formula: see text]). To corroborate the importance of the slowdown, we validate our results by estimating the time to sputum culture conversion and compare the results to a different dose ranging trial. CONCLUSIONS Our findings indicate that higher doses, specifically higher peak concentrations may be used to optimize rifampicin treatments by accelerating bacterial killing in the slow phase. It adds to the growing body of literature supporting higher rifampicin doses for shortening tuberculosis treatments.
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Affiliation(s)
- Antal Martinecz
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Martin J Boeree
- Department of Lung Diseases, Radboud Institute for Health Sciences, Radboud university medical center, Nijmegen, the Netherlands
| | - Andreas H Diacon
- Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
- TASK Applied Science, Cape Town, South Africa
| | - Rodney Dawson
- Division of Pulmonology and Department of Medicine, University of Cape Town, Cape Town, South Africa
- University of Cape Town Lung Institute, Cape Town, South Africa
| | - Colin Hemez
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Graduate program in Biophysics, Harvard University, Boston, Massachusetts, United States of America
| | - Rob E Aarnoutse
- Department of Pharmacy, Radboud Institute for Health Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Pia Abel Zur Wiesch
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, Eberly College of Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Norwegian Institute of Public Health (Folkehelseinstitutt), Oslo, Norway
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Monique OPPERMAN, Ilse DUPREEZ. FACTORS CONTRIBUTING TO PULMONARY TB TREATMENT LOST TO FOLLOW-UP IN DEVELOPING COUNTRIES: AN OVERVIEW. Afr J Infect Dis 2022; 17:60-73. [PMID: 36756489 PMCID: PMC9885020 DOI: 10.21010/ajidv17i1.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 12/24/2022] Open
Abstract
Background Despite the available treatment options, pulmonary tuberculosis (TB) remains a leading cause of disease-related deaths worldwide. Treatment non-adherence/lost to follow-up (LTFU), particularly in developing countries, is a continuous concern. LTFU prolongs TB infectiousness and contributes to TB treatment failure, relapse, and death. Furthermore, LTFU also delays global TB eradication by promoting TB spread and drug-resistant TB strain development.[1] The purpose of this paper is to give an overview of the commonly observed risk factors associated with TB treatment LTFU in developing countries. Materials and Methods A literature survey was done of studies published in the past decade, which evaluated the risk factors for LTFU in TB patients, specifically in developing countries. Furthermore, some prospective TB treatment adherence initiatives and the feasibility of these initiatives within developing countries were assessed.[3]. Results Several variables, including socio-demographic, patient-related, TB disease and other health-related-factors, healthcare and system determinants, as well as treatment-related factors, were identified to increase the risk of TB treatment LTFU. More recently applied adherence interventions in developing countries, show potential for implementation on a larger scale. Conclusion Successful TB treatment is contingent on treatment adherence, and by addressing these persisting LTFU risk factors, treatment adherence in developing countries may be improved.
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Affiliation(s)
- OPPERMAN, Monique
- Human Metabolomics, North-West University (Potchefstroom Campus), Private Bag x6001, Box 269, Potchefstroom, South Africa, 2531
| | - DU PREEZ, Ilse
- Human Metabolomics, North-West University (Potchefstroom Campus), Private Bag x6001, Box 269, Potchefstroom, South Africa, 2531,Corresponding Author’s E-Mail:
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Abstract
The emergence of drug resistance during antimicrobial therapy is a major global health problem, especially for chronic infections like human immunodeficiency virus, hepatitis B and C, and tuberculosis. Sub-optimal adherence to long-term treatment is an important contributor to resistance risk. New long-acting drugs are being developed for weekly, monthly or less frequent dosing to improve adherence, but may lead to long-term exposure to intermediate drug levels. In this study, we analyse the effect of dosing frequency on the risk of resistance evolving during time-varying drug levels. We find that long-acting therapies can increase, decrease or have little effect on resistance, depending on the source (pre-existing or de novo) and degree of resistance, and rates of drug absorption and clearance. Long-acting therapies with rapid drug absorption, slow clearance and strong wild-type inhibition tend to reduce resistance caused by partially resistant strains in the early stages of treatment even if they do not improve adherence. However, if subpopulations of microbes persist and can reactivate during sub-optimal treatment, longer-acting therapies may substantially increase the resistance risk. Our results show that drug kinetics affect selection for resistance in a complicated manner, and that pathogen-specific models are needed to evaluate the benefits of new long-acting therapies.
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Affiliation(s)
- Anjalika Nande
- Program for Evolutionary Dynamics, Harvard University, Cambridge, MA 02138, USA
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Alison L. Hill
- Program for Evolutionary Dynamics, Harvard University, Cambridge, MA 02138, USA
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, USA
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Sabin LL, Thulasingam M, Carwile M, Babu SP, Knudsen S, Dong L, Stephens J, Fernandes P, Cintron C, Horsburgh CR, Salgame P, Ellner JJ, Sarkar S, Hochberg NS. 'People listen more to what actors say': A qualitative study of tuberculosis-related knowledge, behaviours, stigma, and potential interventions in Puducherry, India. Glob Public Health 2022; 17:2898-2910. [PMID: 34657567 DOI: 10.1080/17441692.2021.1990372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
India has made substantial advancements in reducing the burden of tuberculosis (TB), but persons living with active TB (PLWATB) still face myriad challenges in seeking and receiving care, including TB-related stigma. To meet the END TB targets, it is critical that PLWATB engage in care and are able to adhere to treatment. This qualitative study aimed to understand TB-related stigma (perceived, enacted, and internalised) and possible interventions to reduce stigma in Puducherry and Tamil Nadu, India. We conducted 47 in-depth interviews with PLWATB and household members and eight focus group discussions: two each with PLWATB, their household members, healthcare workers, and key informants. We found varying TB-related knowledge: the vast majority of interview participants reported incorrect modes of transmission, although most were also aware that TB is curable. Participants reported high levels of perceived stigma, with nearly two-thirds of PLWATB choosing to hide their disease to avoid being stigmatised in their community. Participants supported interventions including celebrity advocacy and school-based programming to increase community knowledge and reduce enacted stigma as well as support groups and counselling to reduce internalised stigma in PLWATB. This study has the potential to inform future interventions to reduce TB-related stigma in India.
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Affiliation(s)
- Lora L Sabin
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
| | | | - Madeline Carwile
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
| | | | - Selby Knudsen
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Lijia Dong
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
| | - Jessie Stephens
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
| | - Priyanka Fernandes
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Chelsie Cintron
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - C Robert Horsburgh
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA.,Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
| | | | | | - Sonali Sarkar
- Department of Preventive and Social Medicine, JIPMER, Puducherry, India
| | - Natasha S Hochberg
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.,Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA
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Mtafya B, Sabi I, John J, Sichone E, Olomi W, Gillespie SH, Ntinginya NE, Sabiiti W. Systematic assessment of clinical and bacteriological markers for tuberculosis reveals discordance and inaccuracy of symptom-based diagnosis for treatment response monitoring. Front Med (Lausanne) 2022; 9:992451. [DOI: 10.3389/fmed.2022.992451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/28/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundClinical symptoms are the benchmark of tuberculosis (TB) diagnosis and monitoring of treatment response but are not clear how they relate to TB bacteriology, particularly the novel tuberculosis-molecular bacterial load assay (TB-MBLA).MethodsPresumptive cases were bacteriologically confirmed for TB and assessed for symptoms and bacteriological resolution using smear microscopy (SM), culture, and TB-MBLA over 6-month treatment course. Kaplan–Meier and Kappa statistics were used to test the relationship between symptoms and bacteriological positivity.ResultsA cohort of 46 bacteriologically confirmed TB cases were analyzed for treatment response over a 6-month treatment course. Pre-treatment symptoms and bacteriological positivity concurred in over 70% of the cases. This agreement was lost in over 50% of cases whose chest pain, night sweat, and loss of appetite had resolved by week 2 of treatment. Cough resolved at a 3.2% rate weekly and was 0.3% slower than the combined bacteriological (average of MGIT and TB-MBLA positivity) resolution rate, 3.5% per week. A decrease in TB-MBLA positivity reflected a fall in bacillary load, 5.7 ± 1.3- at baseline to 0.30 ± 1.0- log10 eCFU/ml at month 6, and closer to cough resolution than other bacteriological measures, accounting for the only one bacteriologically positive case out of seven still coughing at month 6. Low baseline bacillary load patients were more likely to be bacteriologically negative, HR 5.6, p = 0.003 and HR 3.2, p = 0.014 by months 2 and 6 of treatment, respectively.ConclusionThe probability of clinical symptoms reflecting bacteriological positivity weakens as the patient progresses on anti-TB therapy, making the symptom-based diagnosis a less reliable marker of treatment response.
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vCOMBAT: a novel tool to create and visualize a computational model of bacterial antibiotic target-binding. BMC Bioinformatics 2022; 23:22. [PMID: 34991453 PMCID: PMC8734216 DOI: 10.1186/s12859-021-04536-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 12/14/2021] [Indexed: 11/16/2022] Open
Abstract
Background As antibiotic resistance creates a significant global health threat, we need not only to accelerate the development of novel antibiotics but also to develop better treatment strategies using existing drugs to improve their efficacy and prevent the selection of further resistance. We require new tools to rationally design dosing regimens from data collected in early phases of antibiotic and dosing development. Mathematical models such as mechanistic pharmacodynamic drug-target binding explain mechanistic details of how the given drug concentration affects its targeted bacteria. However, there are no available tools in the literature that allow non-quantitative scientists to develop computational models to simulate antibiotic-target binding and its effects on bacteria. Results In this work, we have devised an extension of a mechanistic binding-kinetic model to incorporate clinical drug concentration data. Based on the extended model, we develop a novel and interactive web-based tool that allows non-quantitative scientists to create and visualize their own computational models of bacterial antibiotic target-binding based on their considered drugs and bacteria. We also demonstrate how Rifampicin affects bacterial populations of Tuberculosis bacteria using our vCOMBAT tool. Conclusions The vCOMBAT online tool is publicly available at https://combat-bacteria.org/. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04536-3.
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Temporal Factors and Missed Doses of Tuberculosis Treatment. A Causal Associations Approach to Analyses of Digital Adherence Data. Ann Am Thorac Soc 2021; 17:438-449. [PMID: 31860328 PMCID: PMC7175980 DOI: 10.1513/annalsats.201905-394oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Rationale: Tuberculosis treatment lasts for 6 months or more. Treatment adherence is critical; regimen length, among other factors, makes this challenging. Globally, analyses mapping common types of nonadherence are lacking. For example, is there a greater challenge resulting from early treatment cessation (discontinuation) or intermittent missed doses (suboptimal dosing implementation)? This is essential knowledge for the development of effective interventions and more “forgiving” regimens, as well as to direct national tuberculosis programs. Objectives: To granularly describe how patients take their tuberculosis medication and the temporal factors associated with missed doses. Methods: The present study included patients with pulmonary tuberculosis enrolled in the control arm of a pragmatic, cluster-randomized trial in China of electronic reminders to improve treatment adherence. Treatment was the standard 6-month course (180 d), dosed every other day (90 doses). Medication monitor boxes recorded adherence (box opening) without prompting reminders. Patterns of adherence were visualized and described. Mixed-effects logistic regression models examined the temporal factors associated with per-dose suboptimal dosing implementation, adjusting for clustering within a participant. Cox regression models were used to examine the association between early suboptimal dosing implementation and permanent discontinuation. Results: Across 780 patients, 16,794 (23.9%) of 70,200 doses were missed, 9,487 of which were from suboptimal dosing implementation (56.5%). By 60 days, 5.1% of participants had discontinued, and 14.4% had discontinued by 120 days. Most participants (95.9%) missed at least one dose. The majority of gaps were of a single dose (71.4%), although 22.6% of participants had at least one gap of 2 weeks or more. In adjusted models, the initiation–continuation phase transition (odds ratio, 3.07 [95% confidence interval, 2.68–3.51]) and national holidays (1.52 [1.39–1.65]) were associated with increased odds of suboptimal dosing implementation. Early-stage suboptimal dosing implementation was associated with increased discontinuation rates. Conclusions: Digital tools provide an unprecedented step change in describing and addressing nonadherence. In our setting, nonadherence was common; patients displayed a complex range of patterns. Dividing nonadherence into suboptimal dosing implementation and discontinuation, we found that both increased over time. Discontinuation was associated with early suboptimal dosing implementation. These apparent causal associations between temporal factors and nonadherence present opportunities for targeted interventions. Clinical trial registered with the ISRCTN Registry (ISRCTN46846388).
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Ajema D, Shibru T, Endalew T, Gebeyehu S. Level of and associated factors for non-adherence to anti-tuberculosis treatment among tuberculosis patients in Gamo Gofa zone, southern Ethiopia: cross-sectional study. BMC Public Health 2020; 20:1705. [PMID: 33187496 PMCID: PMC7666453 DOI: 10.1186/s12889-020-09827-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 11/04/2020] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Non-adherence to anti-TB treatment is one of the crucial challenges in improving tuberculosis (TB) treatment outcomes and reducing healthcare costs. The poor adherence to anti-TB treatment among patients with TB is a major problem in Ethiopia. This study aimed to assess the level of and associated factors for non-adherence to anti-TB therapy among patients with tuberculosis in the Gamo Gofa Zone. METHODS A cross-sectional study was conducted at Gamo Gofa Zone from July 20 - August 30, 2017. A multi-stage sampling technique was used. The study included 289 patients who were on anti-TB treatment. Data were collected by trained data collectors using a structured and pre-tested questionnaire through interviews. A multiple logistic regression model was fitted using SPSS 23 to identify factors associated with non-adherence to anti-TB treatment at a 5% significance level. RESULTS We found that 16.5% of the participants were non-adherent for anti-TB treatment. Failure to disclose one's TB status to his or her family (AOR = 31.7; 95% CI: 9.1-111.1), having no information on the expected adverse events (AOR = 31.1; 95% CI: 7.5-128.3), past anti-TB treatment history (AOR = 5.3; 95% CI: 1.5-18.8) and a smoking cigarette (AOR = 11.7; 95% CI: 3.2-43.03) were found to be associated with a higher odds of being non-adherent to anti-TB treatment. CONCLUSIONS The level of non-adherence to anti-TB treatment among TB patients was high. Health care providers should counsel TB patients on the expected adverse events and measures to be taken when patients face the expected adverse events. They should also counsel their patients to disclose their TB status to his or her family and for ceasing cigarette smoking.
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Affiliation(s)
- Dessalegn Ajema
- School of Public Health, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Tamiru Shibru
- School of Medicine, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Temesgen Endalew
- School of Medicine, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Selamawit Gebeyehu
- School of Public Health, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
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Stagg HR, Abubakar I, Campbell CN, Copas A, Darvell M, Horne R, Kielmann K, Kunst H, Mandelbaum M, Pickett E, Story A, Vidal N, Wurie FB, Lipman M. IMPACT study on intervening with a manualised package to achieve treatment adherence in people with tuberculosis: protocol paper for a mixed-methods study, including a pilot randomised controlled trial. BMJ Open 2019; 9:e032760. [PMID: 31852704 PMCID: PMC6937100 DOI: 10.1136/bmjopen-2019-032760] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Compared with the rest of the UK and Western Europe, England has high rates of the infectious disease tuberculosis (TB). TB is curable, although treatment is for at least 6 months and longer when disease is drug resistant. If patients miss too many doses (non-adherence), they may transmit infection for longer and the infecting bacteria may develop resistance to the standard drugs used for treatment. Non-adherence may therefore risk both their health and that of others. Within England, certain population groups are thought to be at higher risk of non-adherence, but the factors contributing to this have been insufficiently determined, as have the best interventions to promote adherence. The objective of this study was to develop a manualised package of interventions for use as part of routine care within National Health Services to address the social and cultural factors that lead to poor adherence to treatment for TB disease. METHODS AND ANALYSIS This study uses a mixed-methods approach, with six study components. These are (1) scoping reviews of the literature; (2) qualitative research with patients, carers and healthcare professionals; (3) development of the intervention; (4) a pilot randomised controlled trial of the manualised intervention; (5) a process evaluation to examine clinical utility; and (6) a cost analysis. ETHICS AND DISSEMINATION This study received ethics approval on 24 December 2018 from Camberwell St. Giles Ethics Committee, UK (REC reference 18/LO/1818). Findings will be published and disseminated through peer-reviewed publications and conference presentations, published in an end of study report to our funder (the National Institute for Health Research, UK) and presented to key stakeholders. TRIAL REGISTRATION NUMBER ISRCTN95243114 SECONDARY IDENTIFYING NUMBERS: University College London/University College London Hospitals Joint Research Office 17/0726.National Institute for Health Research, UK 16/88/06.
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Affiliation(s)
- Helen R Stagg
- Centre for Global Health, Usher Institute, University of Edinburgh, Edinburgh, UK
| | - Ibrahim Abubakar
- Institute for Global Health, University College London, London, UK
| | | | - Andrew Copas
- Centre for Pragmatic Global Health Trials, Institute of Global Health, University College London, London, UK
| | | | - Robert Horne
- UCL School of Pharmacy, University College London, London, UK
| | - Karina Kielmann
- Institute for Global Health and Development, Queen Margaret University Edinburgh, Edinburgh, UK
| | - Heinke Kunst
- Department of Respiratory Medicine, Queen Mary University of London, London, UK
| | | | - Elisha Pickett
- Department of Respiratory Medicine, Royal Free London NHS Foundation Trust, London, UK
| | - Alistair Story
- Find&Treat, University College Hospitals NHS Foundation Trust, London, UK
| | - Nicole Vidal
- Institute for Global Health and Development, Queen Margaret University Edinburgh, Edinburgh, UK
| | - Fatima B Wurie
- Institute for Global Health, University College London, London, UK
| | - Marc Lipman
- UCL Respiratory, University College London, London, UK
- Department of Respiratory Medicine, Royal Free London NHS Foundation Trust, London, UK
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Browne SH, Umlauf A, Tucker AJ, Low J, Moser K, Gonzalez Garcia J, Peloquin CA, Blaschke T, Vaida F, Benson CA. Wirelessly observed therapy compared to directly observed therapy to confirm and support tuberculosis treatment adherence: A randomized controlled trial. PLoS Med 2019; 16:e1002891. [PMID: 31584944 PMCID: PMC6777756 DOI: 10.1371/journal.pmed.1002891] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 08/27/2019] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Excellent adherence to tuberculosis (TB) treatment is critical to cure TB and avoid the emergence of resistance. Wirelessly observed therapy (WOT) is a novel patient self-management system consisting of an edible ingestion sensor (IS), external wearable patch, and paired mobile device that can detect and digitally record medication ingestions. Our study determined the accuracy of ingestion detection in clinical and home settings using WOT and subsequently compared, in a randomized control trial (RCT), confirmed daily adherence to medication in persons using WOT or directly observed therapy (DOT) during TB treatment. METHODS AND FINDINGS We evaluated WOT in persons with active Mycobacterium tuberculosis complex disease using IS-enabled combination isoniazid 150 mg/rifampin 300 mg (IS-Rifamate). Seventy-seven participants with drug-susceptible TB in the continuation phase of treatment, prescribed daily isoniazid 300 mg and rifampin 600 mg, used IS-Rifamate. The primary endpoints of the trial were determination of the positive detection accuracy (PDA) of WOT, defined as the percentage of ingestions detected by WOT administered under direct observation, and subsequently the proportion of prescribed doses confirmed by WOT compared to DOT. Initially participants received DOT and WOT simultaneously for 2-3 weeks to allow calculation of WOT PDA, and the 95% confidence interval (CI) was estimated using the bootstrap method with 10,000 samples. Sixty-one participants subsequently participated in an RCT to compare the proportion of prescribed doses confirmed by WOT and DOT. Participants were randomized 2:1 to receive WOT or maximal in-person DOT. In the WOT arm, if ingestions were not remotely confirmed, the participant was contacted within 24 hours by text or cell phone to provide support. The number of doses confirmed was collected, and nonparametric methods were used for group and individual comparisons to estimate the proportions of confirmed doses in each randomized arm with 95% CIs. Sensitivity analyses, not prespecified in the trial registration, were also performed, removing all nonworking (weekend and public holiday) and held-dose days. Participants, recruited from San Diego (SD) and Orange County (OC) Divisions of TB Control and Refugee Health, were 43.1 (range 18-80) years old, 57% male, 42% Asian, and 39% white with 49% Hispanic ethnicity. The PDA of WOT was 99.3% (CI 98.1; 100). Intent-to-treat (ITT) analysis within the RCT showed WOT confirmed 93% versus 63% DOT (p < 0.001) of daily doses prescribed. Secondary analysis removing all nonworking days (weekends and public holidays) and held doses from each arm showed WOT confirmed 95.6% versus 92.7% (p = 0.31); WOT was non-inferior to DOT (difference 2.8% CI [-1.8%, 9.1%]). One hundred percent of participants preferred using WOT. WOT associated adverse events were <10%, consisting of minor skin rash and pruritus associated with the patch. WOT provided longitudinal digital reporting in near real time, supporting patient self-management and allowing rapid remote identification of those who needed more support to maintain adherence. This study was conducted during the continuation phase of TB treatment, limiting its generalizability to the entire TB treatment course. CONCLUSIONS In terms of accuracy, WOT was equivalent to DOT. WOT was superior to DOT in supporting confirmed daily adherence to TB medications during the continuation phase of TB treatment and was overwhelmingly preferred by participants. WOT should be tested in high-burden TB settings, where it may substantially support low- and middle-income country (LMIC) TB programs. TRIAL REGISTRATION ClinicalTrials.gov NCT01960257.
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Affiliation(s)
- Sara H. Browne
- University of California San Diego, La Jolla, California, United States of America
- * E-mail:
| | - Anya Umlauf
- University of California San Diego, La Jolla, California, United States of America
| | - Amanda J. Tucker
- University of California San Diego, La Jolla, California, United States of America
| | - Julie Low
- Orange County Health Care Agency, Santa Ana, California, United States of America
| | - Kathleen Moser
- Health and Human Services Agency, San Diego, California, United States of America
| | | | | | | | - Florin Vaida
- University of California San Diego, La Jolla, California, United States of America
| | - Constance A. Benson
- University of California San Diego, La Jolla, California, United States of America
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Dzeyie KA, Basu S, Dikid T, Bhatnagar AK, Chauhan L, Narain J. Epidemiological and behavioural correlates of drug-resistant tuberculosis in a Tertiary Care Centre, Delhi, India. ACTA ACUST UNITED AC 2019; 66:331-336. [PMID: 31439176 DOI: 10.1016/j.ijtb.2018.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/19/2018] [Accepted: 06/22/2018] [Indexed: 11/15/2022]
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Muzanyi G, Mulumba Y, Mubiri P, Mayanja H, Johnson JL, Mupere E. Predictors of recurrent TB in sputum smear and culture positive adults: a prospective cohort study. Afr Health Sci 2019; 19:2091-2099. [PMID: 31656493 PMCID: PMC6794518 DOI: 10.4314/ahs.v19i2.33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective To explore simple inexpensive non-culture based predictors of recurrent pulmonary tuberculosis (PTB). Setting and study population HIV-infected and uninfected adults with the first episode of smear positive, culture-confirmed pulmonary tuberculosis in a high tuberculosis burden country. Design A nested prospective cohort study of participants with pulmonary tuberculosis (PTB) presenting to a hospital out-patient clinic. Results A total of 630 TB culture confirmed participants were followed up for eighteen months of which 57 (9%) developed recurrent recurrent TB. On univariate analysis,4.7% low grade(1+) pre-treatment sputum smear participants developed recurrent tuberculosis Vs 8.8% with high grade(3+) smears (OR=0.31,95%CI: 0.10–0.93, p=0.037).On multivariate analysis: participants with extensive fibro-cavitation had a high risk of recurrent TB Vs minimal end of treatment fibro-cavitation (18%Vs12%, OR=2.3,95%CI:1.09–4.68, p=0.03). Weight gain with HIV infection was assosciated with a high risk of recurrent TB Vs weight gain with no HIV infection(18%Vs 6%, OR=6.8,95%CI:165–27.83, p=0.008) where as weight gain with a low pre-treatment high bacillary burden was assosciated with a low risk of recurrent TB Vs weight gain with a high pre-treatmentbacillary burden(6.5%Vs7.9%, OR=0.2,95%CI:0.05–0.79, p=0.02). Conclusion Extensive end of treatment pulmonary fibro-cavitation, high pre-treatment bacillary burden with no weight gain and HIV infection could be reliable predictors of recurrent tuberculosis.
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Affiliation(s)
- Grace Muzanyi
- Uganda-Case Western Reserve University Research Collaboration, Kampala, Uganda
| | - Y Mulumba
- Uganda Cancer Institute, Kampala, Uganda
| | - Paul Mubiri
- Uganda-Case Western Reserve University Research Collaboration, Kampala, Uganda
| | - Harriet Mayanja
- Uganda-Case Western Reserve University Research Collaboration, Kampala, Uganda
| | - John L Johnson
- Uganda-Case Western Reserve University Research Collaboration, Kampala, Uganda
- Tuberculosis Research Unit, Department of Medicine, Case Western Reserve University and University Hospitals Case Medical Center, Cleveland, Ohio, U.S.A
| | - Ezekiel Mupere
- Uganda-Case Western Reserve University Research Collaboration, Kampala, Uganda
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Fang XH, Dan YL, Liu J, Jun L, Zhang ZP, Kan XH, Ma DC, Wu GC. Factors influencing completion of treatment among pulmonary tuberculosis patients. Patient Prefer Adherence 2019; 13:491-496. [PMID: 31114167 PMCID: PMC6497847 DOI: 10.2147/ppa.s198007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/12/2019] [Indexed: 12/20/2022] Open
Abstract
Objective: This study aimed to understand the influencing factors of treatment completion among pulmonary tuberculosis (PTB) patients in Anhui province, eastern People's Republic of China, in order to provide scientific evidence for improving the follow-up rate and treatment completion rate. Methods: A total of 262 PTB patients in six counties (districts) of Anhui province were investigated by questionnaire, and data about treatment interruption were collected. Results: The main causes of treatment interruption were forgetting to take medicine (24.5%), drug side effects (23.3%), and symptomatic improvement (19.5%). The education background, patient type, cause of interruption, and tracking method were factors influencing completion of treatment (all P<0.05). The education level was positively associated with the treatment completion rate. New smear-positive patients had a significantly higher completion rate than others. The patients interrupted by drug side effects had the highest risk of interruption. In terms of the tracking method, the completion rate of patients tracked by the rural medical staff was significantly lower. Conclusions: The management of PTB patients by medication supervision should be strengthened, especially for those with low education level and who had drug side effects, in order to improve their treatment completion rate.
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Affiliation(s)
- Xue-Hui Fang
- Department of Science and Education, Anhui Provincial TB Institute, Hefei, Anhui, People’s Republic of China
| | - Yi-Lin Dan
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui, People’s Republic of China
| | - Jie Liu
- Department of Science and Education, Anhui Provincial TB Institute, Hefei, Anhui, People’s Republic of China
| | - Lei Jun
- Department of Science and Education, Anhui Provincial TB Institute, Hefei, Anhui, People’s Republic of China
| | - Zhi-Ping Zhang
- Department of Tuberculosis Prevention, Anqing Center for Disease Control and Prevention, Anqing, Anhui, People’s Republic of China
| | - Xiao-Hong Kan
- Department of Science and Education, Anhui Provincial TB Institute, Hefei, Anhui, People’s Republic of China
| | - Dong-Chun Ma
- Department of Science and Education, Anhui Provincial TB Institute, Hefei, Anhui, People’s Republic of China
- Correspondence: Dong-Chun MaDepartment of Science and Education, Anhui Provincial TB Institute, Hefei, Anhui, 230022, People’s Republic of ChinaEmail
| | - Guo-Cui Wu
- School of Nursing, Anhui Medical University, Hefei, Anhui, People’s Republic of China
- Guo-Cui WuSchool of Nursing, Anhui Medical University, 15 Feicui Road, Hefei, Anhui, 230601, People’s Republic of ChinaEmail
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Hill AL, Rosenbloom DIS, Nowak MA, Siliciano RF. Insight into treatment of HIV infection from viral dynamics models. Immunol Rev 2018; 285:9-25. [PMID: 30129208 PMCID: PMC6155466 DOI: 10.1111/imr.12698] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The odds of living a long and healthy life with HIV infection have dramatically improved with the advent of combination antiretroviral therapy. Along with the early development and clinical trials of these drugs, and new field of research emerged called viral dynamics, which uses mathematical models to interpret and predict the time-course of viral levels during infection and how they are altered by treatment. In this review, we summarize the contributions that virus dynamics models have made to understanding the pathophysiology of infection and to designing effective therapies. This includes studies of the multiphasic decay of viral load when antiretroviral therapy is given, the evolution of drug resistance, the long-term persistence latently infected cells, and the rebound of viremia when drugs are stopped. We additionally discuss new work applying viral dynamics models to new classes of investigational treatment for HIV, including latency-reversing agents and immunotherapy.
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Affiliation(s)
- Alison L. Hill
- Program for Evolutionary DynamicsHarvard UniversityCambridgeMassachusetts
| | - Daniel I. S. Rosenbloom
- Department of PharmacokineticsPharmacodynamics, & Drug MetabolismMerck Research LaboratoriesKenilworthNew Jersey
| | - Martin A. Nowak
- Program for Evolutionary DynamicsHarvard UniversityCambridgeMassachusetts
| | - Robert F. Siliciano
- Department of MedicineJohns Hopkins University School of MedicineBaltimoreMaryland
- Howard Hughes Medical InstituteBaltimoreMaryland
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Distinct MHC class I-like interacting invariant T cell lineage at the forefront of mycobacterial immunity uncovered in Xenopus. Proc Natl Acad Sci U S A 2018; 115:E4023-E4031. [PMID: 29610296 DOI: 10.1073/pnas.1722129115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The amphibian Xenopus laevis is to date the only species outside of mammals where a MHC class I-like (MHC-like) restricted innate-like (i) T cell subset (iVα6 T cells) reminiscent of CD1d-restricted iNKT cells has been identified and functionally characterized. This provides an attractive in vivo model to study the biological analogies and differences between mammalian iT cells and the evolutionarily antecedent Xenopus iT cell defense system. Here, we report the identification of a unique iT cell subset (Vα45-Jα1.14) requiring a distinct MHC-like molecule (mhc1b4.L or XNC4) for its development and function. We used two complementary reverse genetic approaches: RNA interference by transgenesis to impair expression of either XNC4 or the Vα45-Jα1.14 rearrangement, and CRISPR/Cas9-mediated disruption of the Jα1.14 gene segment. Both XNC4 deficiency that ablates iVα45T cell development and the direct disruption of the iVα45-Jα1.14 T cell receptor dramatically impairs tadpole resistance to Mycobacterium marinum (Mm) infection. The higher mortality of Mm-infected tadpoles deficient for iVα45T cells correlates with dysregulated expression responses of several immune genes. In contrast, iVα45-Jα1.14-deficient tadpoles remain fully competent against infection by the ranavirus FV3, which indicates a specialization of this unique iT cell subset toward mycobacterial rather than viral pathogens that involve iVα6 T cells. These data suggest that amphibians, which are evolutionarily separated from mammals by more than 350 My, have independently diversified a prominent and convergent immune surveillance system based on MHC-like interacting innate-like T cells.
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