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Infectious and clinical tuberculosis trajectories: Bayesian modeling with case finding implications. Proc Natl Acad Sci U S A 2022; 119:e2211045119. [PMID: 36534797 PMCID: PMC9907102 DOI: 10.1073/pnas.2211045119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The importance of finding people with undiagnosed tuberculosis (TB) hinges on their future disease trajectories. Assays for systematic screening should be optimized to find those whose TB will contribute most to future transmission or morbidity. In this study, we constructed a mathematical model that tracks the future trajectories of individuals with TB at a cross-sectional timepoint ("baseline"), classifying them by bacterial burden (smear positive/negative) and symptom status (symptomatic/subclinical). We used Bayesian methods to calibrate this model to targets derived from historical survival data and notification, mortality, and prevalence data from five countries. We combined resulting disease trajectories with evidence on infectiousness to estimate each baseline TB state's contribution to future transmission. For a person with smear-negative subclinical TB at baseline, the expected future duration of disease was short (mean 4.8 [95% uncertainty interval 3.3 to 8.4] mo); nearly all disease courses ended in spontaneous resolution, not treatment. In contrast, people with baseline smear-positive subclinical TB had longer undiagnosed disease durations (15.9 [11.1 to 23.5] mo); nearly all eventually developed symptoms and ended in treatment or death. Despite accounting for only 11 to 19% of prevalent disease, smear-positive subclinical TB accounted for 35 to 51% of future transmission-a greater contribution than symptomatic or smear-negative TB. Subclinical TB with a high bacterial burden accounts for a disproportionate share of future transmission. Priority should be given to developing inexpensive, easy-to-use assays for screening both symptomatic and asymptomatic individuals at scale-akin to rapid antigen tests for other diseases-even if these assays lack the sensitivity to detect paucibacillary disease.
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Heffernan C, Savić RM, Long RG, Raviglione MC, Ferrara G. Responding to the post-pandemic crisis: post-exposure prophylaxis for TB. Int J Tuberc Lung Dis 2022; 26:807-810. [PMID: 35996295 PMCID: PMC9423019 DOI: 10.5588/ijtld.22.0342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- C Heffernan
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - R M Savić
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, USA
| | - R G Long
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada, Alberta Health Services, Edmonton, AB, Canada
| | - M C Raviglione
- Centre for Multidisciplinary Research in Health Science, University of Milan, Milan, Italy
| | - G Ferrara
- Division of Pulmonary Medicine, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada, Alberta Health Services, Edmonton, AB, Canada
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Karbito K, Susanto H, Adi MS, Sulistiyani S, Handayani OWK, Sofro MAU. Latent tuberculosis infection in family members in household contact with active tuberculosis patients in Semarang City, Central Java, Indonesia. J Public Health Afr 2022; 13:2157. [PMID: 36051527 PMCID: PMC9425956 DOI: 10.4081/jphia.2022.2157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/22/2022] [Indexed: 11/22/2022] Open
Abstract
A quarter of the world’s population is infected with Mycobacterium tuberculosis (M.tb), 10% of cases develop active tuberculosis (TB), and 90% have a latent TB infection. Family members of TB patients have the highest potential for latent TB infection. This study aims to identify latent TB infection and risk factors in family members within the household contacts of active TB patients. This study used a crosssectional study design with a contact tracing method. The selected subjects were 138 people from 241 total family members of 112 active TB patients. Subjects underwent a tuberculin skin test (TST), using 2 units of tuberculin (TU) purified protein derivative (PPD) 0.1 mL (PT. Bio Farma Persero, Bandung, Indonesia). Data risk factors were collected during home visits. Data were analyzed using the chi-square test and multiple logistic regression. A total of 63.8% (88/138) of family members of active TB patients’ household contacts had latent TB infection. The type of occupation of laborers/ farmers/fishers is the most dominant risk factor associated with latent TB infection (AOR: 7.04; 95% CI: 1.70–29.02), followed by unqualified bedroom density (<8 m2/2 people) (AOR: 5.33; 95% CI: 2.44– 12.71) and contact duration ≥5 hours/day (AOR: 4.70; 95% CI:1.33–16.66). Latent TB infection in family members of active TB patients’ household contacts was quite high. Occupation type, contact duration, and bedroom density were simultaneously confirmed as the main risk factors related to latent TB infection. Therefore, it is recommended to identify and prevent latent TB infection in family members in household contact with active TB patients.
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Reddy D, Ma Y, Lakshminarayanan S, Sahu S, White LF, Reshma A, Roy G, Salgame P, Knudsen S, Cintron C, Ellner JJ, Horsburgh CR, Sarkar S, Hochberg NS. Severe undernutrition in children affects tuberculin skin test performance in Southern India. PLoS One 2021; 16:e0250304. [PMID: 34270546 PMCID: PMC8284816 DOI: 10.1371/journal.pone.0250304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/04/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Undernutrition impairs immunity to Mycobacterium tuberculosis and is a risk factor for tuberculosis disease (TB). We aim to investigate if severe undernutrition affects the tuberculin skin test (TST) response among household contacts (HHCs) of pulmonary TB cases. METHODS We analyzed data from HHCs (> five years) of pulmonary TB cases in Southern India. Undernutrition was defined as per World Health Organization based on body mass index (BMI) for adults (undernutrition 16-18.4 and severe undernutrition <16 kg/m2) and BMI relative to the mean for children (undernutrition 2SD-3SD and severe undernutrition < 3SDs below mean). Univariate and multivariate models of TST positivity (> five mm) were calculated using logistic regression with generalized estimating equations. RESULTS Among 1189 HHCs, 342 were children (age 5-17 years) and 847 were adults. Prevalence of TST positivity in well-nourished, undernourished and severely undernourished children was 135/251 (53.8%), 32/68 (47.1%), and 7/23 (30.4%) respectively; among adults, prevalence of TST positivity was 304/708 (42.9%), 43/112 (38.4%) and 12/26 (46.2%), respectively. Severe undernutrition in children was associated with decreased odds of TST positivity (adjusted odds ratio 0.3; 95%CI 0.1-0.9). CONCLUSION Severe undernutrition in children was associated with decreased odds of TST positivity. False-negative TSTs may result from undernutrition; caution is warranted when interpreting negative results in undernourished populations.
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Affiliation(s)
- Divya Reddy
- Department of Medicine, Pulmonary Division, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Yicheng Ma
- Department of Biostatistics, Boston University, School of Public Health, Boston, Massachusetts, United States of America
| | - Subitha Lakshminarayanan
- Department of Preventive and Social Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Swaroop Sahu
- Department of Preventive and Social Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Laura F. White
- Department of Biostatistics, Boston University, School of Public Health, Boston, Massachusetts, United States of America
| | - Ayiraveetil Reshma
- Department of Preventive and Social Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Gautam Roy
- Department of Preventive and Social Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Padmini Salgame
- Department of Medicine, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America
| | - Selby Knudsen
- Department of Medicine, Section of Infectious Diseases, Boston University, School of Medicine, Boston, Massachusetts, United States of America
| | - Chelsie Cintron
- Department of Medicine, Section of Infectious Diseases, Boston University, School of Medicine, Boston, Massachusetts, United States of America
| | - Jerrold J. Ellner
- Department of Medicine, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America
| | - C. Robert Horsburgh
- Department of Biostatistics, Boston University, School of Public Health, Boston, Massachusetts, United States of America
- Department of Medicine, Section of Infectious Diseases, Boston University, School of Medicine, Boston, Massachusetts, United States of America
- Department of Epidemiology, Boston University, School of Public Health, Boston, Massachusetts, United States of America
| | - Sonali Sarkar
- Department of Preventive and Social Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Natasha S. Hochberg
- Department of Medicine, Section of Infectious Diseases, Boston University, School of Medicine, Boston, Massachusetts, United States of America
- Department of Epidemiology, Boston University, School of Public Health, Boston, Massachusetts, United States of America
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5
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Abebe F. Immunological basis of early clearance of Mycobacterium tuberculosis infection: the role of natural killer cells. Clin Exp Immunol 2021; 204:32-40. [PMID: 33315236 DOI: 10.1111/cei.13565] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022] Open
Abstract
Tuberculosis (TB) kills more people than any other single infectious disease globally. Despite decades of research, there is no vaccine to prevent TB transmission. Bacille Calmette-Guérin (BCG) vaccine, developed a century ago, is effective against childhood (disseminated and miliary) TB. However, its protective efficacy against pulmonary TB varies from 0 to 80% in different populations. One of the main reasons for the lack of an effective vaccine against TB is the lack of complete understanding about correlates of protective immunity on which to base vaccine design and development. However, some household contacts who are extensively exposed to Mtb infection remain persistently negative to tuberculin skin test and interferon-gamma assay. These individuals, called 'resisters', clear Mtb infection early before the development of acquired immunity. The immunological basis of early Mtb clearance is yet to be established; however, innate lymphocytes such as monocytes/macrophages, dendritic cells, neutrophils and natural killer cells, and innate-like T cells such as mucosal-associated invariant T cells, invariant natural killer (NK) T cells and gamma-delta (γδ) T cells, have been implicated in this early protection. In recent years, NK cells have attracted increasing attention because of their role in controlling Mtb infection. Emerging data from animal and epidemiological studies indicate that NK cells play a significant role in the fight against Mtb. NK cells express various surface markers to recognize and kill both Mtb and Mtb-infected cells. This review presents recent advances in our understanding of NK cells in the fight against Mtb early during infection, with emphasis on cohort studies.
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Affiliation(s)
- F Abebe
- Faculty of Medicine, Department of Community Medicine and Global Health, Institute of Health and Society, University of Oslo, Oslo, Norway
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Colangeli R, Gupta A, Vinhas SA, Chippada Venkata UD, Kim S, Grady C, Jones-López EC, Soteropoulos P, Palaci M, Marques-Rodrigues P, Salgame P, Ellner JJ, Dietze R, Alland D. Mycobacterium tuberculosis progresses through two phases of latent infection in humans. Nat Commun 2020; 11:4870. [PMID: 32978384 PMCID: PMC7519141 DOI: 10.1038/s41467-020-18699-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 09/03/2020] [Indexed: 12/21/2022] Open
Abstract
Little is known about the physiology of latent Mycobacterium tuberculosis infection. We studied the mutational rates of 24 index tuberculosis (TB) cases and their latently infected household contacts who developed active TB up to 5.25 years later, as an indication of bacterial physiological state and possible generation times during latent TB infection in humans. Here we report that the rate of new mutations in the M. tuberculosis genome decline dramatically after two years of latent infection (two-sided p < 0.001, assuming an 18 h generation time equal to log phase M. tuberculosis, with latency period modeled as a continuous variable). Alternatively, assuming a fixed mutation rate, the generation time increases over the latency duration. Mutations indicative of oxidative stress do not increase with increasing latency duration suggesting a lack of host or bacterial derived mutational stress. These results suggest that M. tuberculosis enters a quiescent state during latency, decreasing the risk for mutational drug resistance and increasing generation time, but potentially increasing bacterial tolerance to drugs that target actively growing bacteria.
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Affiliation(s)
- Roberto Colangeli
- Department of Medicine, Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Aditi Gupta
- Department of Medicine, Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Solange Alves Vinhas
- Núcleo de Doenças Infecciosas, Universidade Federal do Espírito Santo (UFES), Vitória, Brazil
| | | | - Soyeon Kim
- Frontier Science Foundation, 1371 Beacon Street, Suite #203, Brookline, MA, 02446, USA
| | - Courtney Grady
- Department of Medicine, Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Edward C Jones-López
- Division of Infectious Diseases, Department of Medicine. Keck School of Medicine of USC, University of Southern California Los Angeles, Los Angeles, CA, USA
| | - Patricia Soteropoulos
- The Genomics Center, Rutgers-New Jersey Medical School, Newark, NJ, USA
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Moisés Palaci
- Núcleo de Doenças Infecciosas, Universidade Federal do Espírito Santo (UFES), Vitória, Brazil
| | | | - Padmini Salgame
- Department of Medicine, Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Jerrold J Ellner
- Department of Medicine, Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Reynaldo Dietze
- Núcleo de Doenças Infecciosas, Universidade Federal do Espírito Santo (UFES), Vitória, Brazil
- Global Health & Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - David Alland
- Department of Medicine, Rutgers-New Jersey Medical School, Newark, NJ, USA.
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Ryndak MB, Laal S. Mycobacterium tuberculosis Primary Infection and Dissemination: A Critical Role for Alveolar Epithelial Cells. Front Cell Infect Microbiol 2019; 9:299. [PMID: 31497538 PMCID: PMC6712944 DOI: 10.3389/fcimb.2019.00299] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/02/2019] [Indexed: 12/28/2022] Open
Abstract
Globally, tuberculosis (TB) has reemerged as a major cause of morbidity and mortality, despite the use of the Mycobacterium bovis BCG vaccine and intensive attempts to improve upon BCG or develop new vaccines. Two lacunae in our understanding of the Mycobacterium tuberculosis (M. tb)-host pathogenesis have mitigated the vaccine efforts; the bacterial-host interaction that enables successful establishment of primary infection and the correlates of protection against TB. The vast majority of vaccine efforts are based on the premise that cell-mediated immunity (CMI) is the predominating mode of protection against TB. However, studies in animal models and in humans demonstrate that post-infection, a period of several weeks precedes the initiation of CMI during which the few inhaled bacteria replicate dramatically and disseminate systemically. The “Trojan Horse” mechanism, wherein M. tb is phagocytosed and transported across the alveolar barrier by infected alveolar macrophages has been long postulated as the sole, primary M. tb:host interaction. In the current review, we present evidence from our studies of transcriptional profiles of M. tb in sputum as it emerges from infectious patients where the bacteria are in a quiescent state, to its adaptations in alveolar epithelial cells where the bacteria transform to a highly replicative and invasive phenotype, to its maintenance of the invasive phenotype in whole blood to the downregulation of invasiveness upon infection of epithelial cells at an extrapulmonary site. Evidence for this alternative mode of infection and dissemination during primary infection is supported by in vivo, in vitro cell-based, and transcriptional studies from multiple investigators in recent years. The proposed alternative mechanism of primary infection and dissemination across the alveolar barrier parallels our understanding of infection and dissemination of other Gram-positive pathogens across their relevant mucosal barriers in that barrier-specific adhesins, toxins, and enzymes synergize to facilitate systemic establishment of infection prior to the emergence of CMI. Further exploration of this M. tb:non-phagocytic cell interaction can provide alternative approaches to vaccine design to prevent infection with M. tb and not only decrease clinical disease but also decrease the overwhelming reservoir of latent TB infection.
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Affiliation(s)
- Michelle B Ryndak
- Department of Pathology, New York University School of Medicine, New York, NY, United States
| | - Suman Laal
- Department of Pathology, New York University School of Medicine, New York, NY, United States
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Cui Z, Lin D, Chongsuvivatwong V, Graviss EA, Chaiprasert A, Palittapongarnpim P, Lin M, Ou J, Zhao J. Hot and Cold Spot Areas of Household Tuberculosis Transmission in Southern China: Effects of Socio-Economic Status and Mycobacterium tuberculosis Genotypes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16101863. [PMID: 31137811 PMCID: PMC6572207 DOI: 10.3390/ijerph16101863] [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] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/19/2019] [Accepted: 05/23/2019] [Indexed: 11/16/2022]
Abstract
The aims of the study were: (1) compare sociodemographic characteristics among active tuberculosis (TB) cases and their household contacts in cold and hot spot transmission areas, and (2) quantify the influence of locality, genotype and potential determinants on the rates of latent tuberculosis infection (LTBI) among household contacts of index TB cases. Parallel case-contact studies were conducted in two geographic areas classified as "cold" and "hot" spots based on TB notification and spatial clustering between January and June 2018 in Guangxi, China, using data from field contact investigations, whole genome sequencing, tuberculin skin tests (TSTs), and chest radiographs. Beijing family strains accounted for 64.6% of Mycobacterium tuberculosis (Mtb) strains transmitted in hot spots, and 50.7% in cold spots (p-value = 0.02). The positive TST rate in hot spot areas was significantly higher than that observed in cold spot areas (p-value < 0.01). Living in hot spots (adjusted odds ratio (aOR) = 1.75, 95%, confidence interval (CI): 1.22, 2.50), Beijing family genotype (aOR = 1.83, 95% CI: 1.19, 2.81), living in the same room with an index case (aOR = 2.29, 95% CI: 1.5, 3.49), travelling time from home to a medical facility (aOR = 4.78, 95% CI: 2.96, 7.72), history of Bacillus Calmette-Guérin vaccination (aOR = 2.02, 95% CI: 1.13 3.62), and delay in diagnosis (aOR = 2.56, 95% CI: 1.13, 5.80) were significantly associated with positive TST results among household contacts of TB cases. The findings of this study confirmed the strong transmissibility of the Beijing genotype family strains and this genotype's important role in household transmission. We found that an extended traveling time from home to the medical facility was an important socioeconomic factor for Mtb transmission in the family. It is still necessary to improve the medical facility infrastructure and management, especially in areas with a high TB prevalence.
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Affiliation(s)
- Zhezhe Cui
- Department of Tuberculosis Control, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
- Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand.
| | - Dingwen Lin
- Department of Tuberculosis Control, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
| | | | - Edward A Graviss
- Department of Pathology and Genomic Medicine, The Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, TX 77030, USA.
| | - Angkana Chaiprasert
- Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | | | - Mei Lin
- Department of Tuberculosis Control, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
| | - Jing Ou
- Department of Tuberculosis Control, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
| | - Jinming Zhao
- Department of Tuberculosis Control, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
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Ackley SF, Lee RS, Worden L, Zwick E, Porco TC, Behr MA, Pepperell CS. Multiple exposures, reinfection and risk of progression to active tuberculosis. ROYAL SOCIETY OPEN SCIENCE 2019; 6:180999. [PMID: 31031990 PMCID: PMC6458392 DOI: 10.1098/rsos.180999] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 02/20/2019] [Indexed: 05/24/2023]
Abstract
A recent study reported on a tuberculosis (TB) outbreak in a largely Inuit village. Among newly infected individuals, exposure to additional active cases was associated with an increasing probability of developing active disease within a year. Using binomial risk models, we evaluated two potential mechanisms by which multiple infections during the first year following initial infection could account for increasing disease risk with increasing exposures. In the reinfection model, each infectious contact confers an independent risk of an infection, and infections contribute independently to active disease. In the threshold model, disease risk follows a sigmoidal function with small numbers of infectious contacts conferring a low risk of active disease and large numbers of contacts conferring a high risk. To determine the dynamic impact of reinfection during the early phase of infection, we performed simulations from a modified Reed-Frost model of TB dynamics following spread from an initial number of cases. We parametrized this model with the maximum-likelihood estimates from the reinfection and threshold models in addition to the observed distribution of exposures among new infections. We find that both models can plausibly account for the observed increase in disease risk with increasing infectious contacts, but the threshold model confers a better fit than a nested model without a threshold (p = 0.04). Our simulations indicate that multiple exposures to infectious individuals during this critical time period can lead to dramatic increases in outbreak size. In order to decrease TB burden in high-prevalence settings, it may be necessary to implement measures aimed at preventing repeated exposures, in addition to preventing primary infection.
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Affiliation(s)
- Sarah F. Ackley
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
- Proctor Foundation, University of California, San Francisco, CA, USA
| | - Robyn S. Lee
- Department of Epidemiology, Harvard University, School of Public Health, Boston, MA, USA
| | - Lee Worden
- Proctor Foundation, University of California, San Francisco, CA, USA
| | - Erin Zwick
- Department of Population Health Sciences, University of Wisconsin – Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Travis C. Porco
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
- Proctor Foundation, University of California, San Francisco, CA, USA
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Marcel A. Behr
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- McGill International TB Centre, Montreal, Quebec, Canada
| | - Caitlin S. Pepperell
- Medicine and Medical Microbiology and Immunology, University of Wisconsin – Madison, Madison, WI, USA
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Meermeier EW, Lewinsohn DM. Early clearance versus control: what is the meaning of a negative tuberculin skin test or interferon-gamma release assay following exposure to Mycobacterium tuberculosis? F1000Res 2018; 7. [PMID: 29904578 PMCID: PMC5974584 DOI: 10.12688/f1000research.13224.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/22/2018] [Indexed: 01/01/2023] Open
Abstract
The elimination of tuberculosis (TB) cannot reasonably be achieved by treatment of individual cases and will require an improved vaccine or immunotherapy. A challenge in developing an improved TB vaccine has been the lack of understanding what is needed to generate sterilizing immunity against
Mycobacterium tuberculosis (Mtb) infection. Several epidemiological observations support the hypothesis that humans can eradicate Mtb following exposure. This has been termed early clearance and is defined as elimination of Mtb infection prior to the development of an adaptive immune response, as measured by a tuberculin skin test or interferon-gamma release assay. Here, we examine research into the likelihood of and possible mechanisms responsible for early clearance in household contacts of patients with active TB. We explore both innate and adaptive immune responses in the lung. Enhanced understanding of these mechanisms could be harnessed for the development of a preventative vaccine or immunotherapy.
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Affiliation(s)
- Erin W Meermeier
- Pulmonary and Critical Care Medicine, Department of Medicine, Oregon Health and Science University, Portland, USA
| | - David M Lewinsohn
- Pulmonary and Critical Care Medicine, Department of Medicine, Oregon Health and Science University, Portland, USA.,Department of Medicine, VA Portland Health Care System, Portland, OR, USA
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