The impact of an oral glucose load on IFN-γ-release in persons infected with Mycobacterium tuberculosis.

BACKGROUND AND OBJECTIVE: To diagnose tuberculosis infection (TBI), whole blood is incubated with M.tuberculosis (Mtb)-specific peptides and the release of interferon-γ (IFN-γ) is measured in IFN-γ-release assays (IGRAs). Hyperglycaemia and fluctuations in blood glucose may modulate IFN-γ-release. Here, we investigated if glucose intake affects IFN-γ-release or IGRA results in IGRAs taken during an oral glucose tolerance test (OGTT). METHODS: Persons with TB disease (TB) or TBI underwent a standard 75-g OGTT at the start and end of treatment for TB or TBI. Blood for the IGRA QuantiFERON-TB Gold Plus (QFT) containing Mtb-specific tubes (TB1 and TB2), a non-specific mitogen tube (MIT) and an empty control tube (NIL) was drawn at sample-timepoints -15 (baseline), 60, 90, 120 and 240 min during the OGTT. Blood glucose was measured in parallel at all timepoints. IFN-γ-release (after subtraction of NIL) at each timepoint was compared with baseline using linear-mixed-model analysis. RESULTS: Twenty-four OGTTs from 14 participants were included in the final analysis. Compared to baseline, IFN-γ-release was increased at sample-timepoint 240 min for TB1; geometric mean (95% confidence interval) 3.0 (1.5-6.2) vs 2.5 (1.4-4.4) IU/mL (p = 0.047), and MIT; 182.6 (103.3-322.9) vs 146.0 (84.0-254.1) IU/mL (p = 0.002). Plasma glucose levels were not associated with IFN-γ-release and the QFT test results were unaffected by the OGTT. CONCLUSION: Ingestion of glucose after a 10-h fast was associated with increased IFN-γ-release after 240 min in the MIT tube. However, there was no association between plasma glucose levels at the QFT sampling timepoint and IFN-γ-release. Furthermore, the QFT test results were not affected by glucose intake. The overall effect of an OGTT and prevailing plasma glucose levels on IFN-γ-release in IGRAs seem limited. TRIAL REGISTRATION: Trial registration ID: NCT04830462 ( https://clinicaltrials.gov/study/NCT04830462 ). Registration date: 05-Apr-2021.

The effect of Mycobacterium tuberculosis treatment on thrombelastography-assessed haemostasis: a prospective cohort study.

BACKGROUND AND OBJECTIVE: Tuberculosis disease (TB) and tuberculosis infection (TBI) have been associated with increased risk of cardiovascular disease which may be connected to infection-related haemostatic changes. It is unknown if treatment of Mycobacterium tuberculosis influences haemostasis. Here, we assessed if TB or TBI treatment affects thrombelastography (TEG)-assessed haemostasis. METHODS: Individuals with TB or TBI were included from a TB outpatient clinic in Copenhagen, Denmark. Patients treated with antithrombotic medication or systemic immunosuppressants were excluded. TEG analysis was performed before and after TB/TBI treatment using the TEG®6s analyser to provide data on the reaction time of clot initiation (R) (min), the speed of clot formation (K) (min) and clot build-up (Angle) (°), maximum clot strength (MA) (mm), and clot breakdown/fibrinolysis (LY30) (%). Differences in TEG were assessed using paired t tests. RESULTS: We included eleven individuals with TB with median [interquartile range] [IQR] age 52 (Liu et al. in Medicine (United States) 95, 2016) years and mean (standard deviation) (SD) body mass index (BMI) 24.7 (6.3) kg/m2 as well as 15 individuals with TBI with median [IQR] age 49 (Wells et al. in Am J Respir Crit Care Med 204:583, 2021) years and BMI 26.0 (3.2) kg/m2. Treatment reduced MA for both TB (64.0 (6.3) vs. 57.9 (5.2) mm, p = 0.016) and TBI (61.3 (4.1) vs. 58.6 (5.0) mm, p = 0.023) whereas R, K, Angle and LY30 were unaffected. CONCLUSION: TEG analysis showed that treatments of TB and TBI were associated with reduced MA which may indicate the existence of cardiovascular benefits from therapy. TRIAL REGISTRATION: Registered at ClinicalTrials.gov 05 April 2021 with registration number NCT04830462.

Sources of knowledge empowerment amongst pregnant women with TB disease: A qualitative study in South Africa.

BACKGROUND: Providing relevant knowledge to empower all pregnant women diagnosed and nondiagnosed with tuberculosis (TB) is essential worldwide. Proper dissemination of health information for pregnant women could assist in preventing TB complications amongst women and babies. The study aimed to describe the sources of knowledge that empower pregnant women diagnosed with TB and improve their quality of life in Limpopo Province, South Africa. METHODOLOGY: The study followed a qualitative, exploratory and descriptive research design. The study was conducted in 12 selected primary healthcare facilities in three crisis districts. Thirty-five pregnant women with TB disease were purposively selected, and face-to-face interviews were conducted to generate data, which were analysed using the thematic approach. Measures to ensure trustworthiness and ethical standards were adhered to. RESULTS: The findings of this study revealed that healthcare workers, community stakeholders, and TB ambassadors are the primary sources of knowledge dissemination for capacitating women diagnosed with TB. CONCLUSION: Most pregnant women lacked knowledge regarding TB ambassadors as sources of information for empowering women, community awareness campaigns, and Google searches as sources of information sharing. All stakeholders need to work together, considering the patients' charter for TB care that sets out the right for respect and information sharing. The emphasis of this study was on developing a comprehensive educational intervention that could assist in improving the quality of TB services offered to pregnant women.

1-Year Incidence of Tuberculosis Infection and Disease Among Household Contacts of Rifampin- and Multidrug-Resistant Tuberculosis.

BACKGROUND: Tuberculosis infection (TBI) and TB disease (TBD) incidence remains poorly described following household contact (HHC) rifampin-/multidrug-resistant TB exposure. We sought to characterize TBI and TBD incidence at 1 year in HHCs and to evaluate TB preventive treatment (TPT) use in high-risk groups. METHODS: We previously conducted a cross-sectional study of HHCs with rifampin-/multidrug-resistant TB in 8 high-burden countries and reassessed TBI (interferon-gamma release assay, HHCs aged ≥5 years) and TBD (HHCs all ages) at 1 year. Incidence was estimated across age and risk groups (<5 years; ≥5 years, diagnosed with human immunodeficiency virus [HIV]; ≥5 years, not diagnosed with HIV/unknown, baseline TBI-positive) by logistic or log-binomial regression fitted using generalized estimating equations. RESULTS: Of 1016 HHCs, 850 (83.7%) from 247 households were assessed (median, 51.4 weeks). Among 242 HHCs, 52 tested interferon-gamma release assay-positive, yielding a 1-year 21.6% (95% confidence interval [CI], 16.7-27.4) TBI cumulative incidence. Sixteen of 742 HHCs developed confirmed (n = 5), probable (n = 3), or possible (n = 8) TBD, yielding a 2.3% (95% CI, 1.4-3.8) 1-year cumulative incidence (1.1%; 95% CI, .5-2.2 for confirmed/probable TBD). TBD relative risk was 11.5-fold (95% CI, 1.7-78.7), 10.4-fold (95% CI, 2.4-45.6), and 2.9-fold (95% CI, .5-17.8) higher in age <5 years, diagnosed with HIV, and baseline TBI high-risk groups, respectively, vs the not high-risk group (P = .0015). By 1 year, 4% (21 of 553) of high-risk HHCs had received TPT. CONCLUSIONS: TBI and TBD incidence continued through 1 year in rifampin-/multidrug-resistant TB HHCs. Low TPT coverage emphasizes the need for evidence-based prevention and scale-up, particularly among high-risk groups.

Contribution of Reinfection to Annual Rate of Tuberculosis Infection (ARI) and Incidence of Tuberculosis Disease.

BACKGROUND: Modeling studies have concluded that 60-80% of tuberculosis (TB) infections result from reinfection of previously infected persons. The annual rate of infection (ARI), a standard measure of the risk of TB infection in a community, may not accurately reflect the true risk of infection among previously infected persons. We constructed a model of infection and reinfection with Mycobacterium tuberculosis to explore the predictive accuracy of ARI and its effect on disease incidence. METHODS: We created a deterministic simulation of the progression from TB infection to disease and simulated the prevalence of TB infection at the beginning and end of a theoretical year of infection. We considered 10 disease prevalence scenarios ranging from 100/100 000 to 1000/100 000 in simulations where TB exposure probability was homogeneous across the whole simulated population or heterogeneously stratified into high-risk and low-risk groups. ARI values, rates of progression from infection to disease, and the effect of multiple reinfections were obtained from published studies. RESULTS: With homogeneous exposure risk, observed ARI values produced expected numbers of infections. However, when heterogeneous risk was introduced, observed ARI was seen to underestimate true ARI by 25-58%. Of the cases of TB disease that occurred, 36% were among previously infected persons when prevalence was 100/100 000, increasing to 79% of cases when prevalence was 1000/100 000. CONCLUSIONS: Measured ARI underestimates true ARI as a result of heterogeneous population mixing. The true force of infection in a community may be greater than previously appreciated. Hyperendemic communities likely contribute disproportionally to the global TB disease burden.

Tuberculosis Infection among Non-US-Born Persons and Persons ≥60 Years of Age, United States, 2019-2020.

We examined tuberculosis (TB) infection results for the United States from the 2019-2020 National Health and Nutrition Examination Survey. Over this period, 10% of non-US-born persons and 7% of those >60 years of age tested positive for TB infection. These results provide up-to-date information on TB infection among study subpopulations.

Vitamin E Status Is Inversely Associated with Risk of Incident Tuberculosis Disease among Household Contacts.

Background: Few studies have previously assessed how pre-existing vitamin E status is associated with risk of tuberculosis (TB) disease progression. Objective: We evaluated the association between baseline plasma concentrations of 3 vitamin E isomers (α-tocopherol, γ-tocopherol, and δ-tocopherol) and TB disease risk. Methods: We conducted a case-control study nested within a longitudinal cohort of household contacts (HHCs) of pulmonary TB cases in Lima, Peru. We defined cases as HHCs who developed active TB disease ≥15 d after the diagnosis of the index patient, and we matched each case to 4 control cases who did not develop active TB based on age by year and gender. We used univariate and multivariate conditional logistic regression to calculate ORs for incident TB disease by plasma concentrations of α-tocopherol, γ-tocopherol, and δ-tocopherol. Results: Among 6751 HIV-negative HHCs who provided baseline blood samples, 180 developed secondary TB during follow-up. After controlling for possible confounders, we found that baseline α-tocopherol deficiency conferred increased risk of incident TB disease (adjusted OR: 1.59; 95% CI: 1.02, 2.50; P = 0.04). Household contacts in the lowest tertile of δ-tocopherol were also at increased risk of progression to TB disease compared to those in the highest tertile (tertile 1 compared with tertile 3, adjusted OR: 2.29; 95% CI: 1.29, 4.09; P-trend = 0.005). We found no association between baseline concentration of γ-tocopherol and incident TB disease. Conclusions: Vitamin E deficiency was associated with an increased risk of progression to TB disease among HHCs of index TB cases. Assessment of vitamin E status among individuals at high risk for TB disease may play a role in TB control efforts.

Impact of Vitamin A and Carotenoids on the Risk of Tuberculosis Progression.

BACKGROUND: Low and deficient levels of vitamin A are common in low- and middle-income countries where tuberculosis burden is high. We assessed the impact of baseline levels of vitamin A and carotenoids on tuberculosis disease risk. METHODS: We conducted a case-control study nested within a longitudinal cohort of household contacts (HHCs) of pulmonary tuberculosis case patients in Lima, Peru. We defined case patients as human immunodeficiency virus (HIV)-negative HHCs with blood samples in whom tuberculosis disease developed ≥15 days after enrollment of the index patient. For each case patient, we randomly selected 4 controls from among contacts in whom tuberculosis disease did not develop, matching for sex and year of age. We used conditional logistic regression to estimate odds ratios for incident tuberculosis disease by vitamin A and carotenoids levels, controlling for other nutritional and socioeconomic factors. RESULTS: Among 6751 HIV-negative HHCs with baseline blood samples, 192 had secondary tuberculosis disease during follow-up. We analyzed 180 case patients with viable samples and 709 matched controls. After controlling for possible confounders, we found that baseline vitamin A deficiency was associated with a 10-fold increase in risk of tuberculosis disease among HHCs (adjusted odds ratio, 10.53; 95% confidence interval, 3.73-29.70; P < .001). This association was dose dependent, with stepwise increases in tuberculosis disease risk with each decreasing quartile of vitamin A level. CONCLUSIONS: Vitamin A deficiency strongly predicted the risk of incident tuberculosis disease among HHCs of patients with tuberculosis. Vitamin A supplementation among individuals at high risk of tuberculosis may provide an effective means of preventing tuberculosis disease.

Tuberculosis progression rates in U.S. Immigrants following screening with interferon-gamma release assays.

BACKGROUND: Interferon-gamma release assays may be used as an alternative to the tuberculin skin test for detection of M. tuberculosis infection. However, the risk of active tuberculosis disease following screening using interferon-gamma release assays in immigrants is not well defined. To address these uncertainties, we determined the incidence rates of active tuberculosis disease in a cohort of high-risk immigrants with Class B TB screened with interferon-gamma release assays (IGRAs) upon arrival in the United States. METHODS: Using a retrospective cohort design, we enrolled recent U.S. immigrants with Class B TB who were screened with an IGRA (QuantiFERON ® Gold or Gold In-Tube Assay) at the San Francisco Department of Public Health Tuberculosis Control Clinic from January 2005 through December 2010. We reviewed records from the Tuberculosis Control Patient Management Database and from the California Department of Public Health Tuberculosis Case Registry to determine incident cases of active tuberculosis disease through February 2015. RESULTS: Of 1233 eligible immigrants with IGRA screening at baseline, 81 (6.6 %) were diagnosed with active tuberculosis disease as a result of their initial evaluation. Of the remaining 1152 participants without active tuberculosis disease at baseline, 513 tested IGRA-positive and 639 tested IGRA-negative. Seven participants developed incident active tuberculosis disease over 7730 person-years of follow-up, for an incidence rate of 91 per 100,000 person-years (95 % CI 43-190). Five IGRA-positive and two IGRA-negative participants developed active tuberculosis disease (incidence rates 139 per 100,000 person-years (95 % CI 58-335) and 48 per 100,000 person-years (95 % CI 12-193), respectively) for an unadjusted incidence rate ratio of 2.9 (95 % CI 0.5-30, p = 0.21). IGRA test results had a negative predictive value of 99.7 % but a positive predictive value of only 0.97 %. CONCLUSIONS: Among high-risk immigrants without active tuberculosis disease at the time of entry into the United States, risk of progression to active tuberculosis disease was higher in IGRA-positive participants compared with IGRA-negative participants. However, these findings did not reach statistical significance, and a positive IGRA at enrollment had a poor predictive value for progressing to active tuberculosis disease. Additional research is needed to identify biomarkers and develop clinical algorithms that can better predict progression to active tuberculosis disease among U.S. immigrants.

Dysregulation of Apoptosis Is a Risk Factor for Tuberculosis Disease Progression.

BACKGROUND: A major barrier to effective tuberculosis control is our limited understanding of risk factors for tuberculosis disease progression. This study examined the role of apoptosis in immunity to tuberculosis. METHODS: Cell subsets from tuberculosis cases and tuberculin skin test-positive (TST(+)) and TST-negative (TST(-)) household contacts (HHCs) were analyzed for expression of annexin-V and propidium iodide by flow cytometry. RNA microarrays were used to determine differences in apoptotic gene expression levels and multiplex ligation-dependent probe amplification was used to analyze gene expression in HHCs who progressed to active tuberculosis. RESULTS: T cells from TST(+)HHC exhibited higher levels of apoptosis than tuberculosis cases; however, tuberculosis cases had a higher proportion of late apoptotic cells within the CD3(+)PD-1(+) subset. Tuberculosis cases had reduced levels of antiapoptotic genes compared to HHCs with a significant reduction in BCL2 associated with disease progression at least 1 year prior to progression. CONCLUSIONS: While T cells are clearly able to mount a robust immune response to Mycobacterium tuberculosis, there are increased levels of apoptosis seen in effector T cells from tuberculosis patients. Dysregulation of several apoptotic genes suggest that apoptosis is a major functional pathway that could be targeted for future host-directed therapeutics.

Combined use of Mycobacterium tuberculosis-specific CD4 and CD8 T-cell responses is a powerful diagnostic tool of active tuberculosis.

Immune-based assays are promising tools to help to formulate diagnosis of active tuberculosis. A multiparameter flow cytometry assay assessing T-cell responses specific to Mycobacterium tuberculosis and the combination of both CD4 and CD8 T-cell responses accurately discriminated between active tuberculosis and latent infection.

Stigma and Associated Sex Disparities Among Patients with Tuberculosis in Uganda: A Cross-Sectional Study.

Background: Tuberculosis (TB) is one of the leading causes of death from a single infectious agent globally. Stigma associated with TB encompassing self-, anticipated-, and public-stigma has significant negative effects on treatment adherence. In Uganda, limited data exist on the prevalence of stigma and its relationship with sex among patients with TB. We evaluate prevalence of three types of stigma and their relationship with the sex of patients undergoing TB treatment. Methods: This cross-sectional study was conducted between July 2020 to March 2021 at selected TB clinics in Kampala, Uganda. Eligible participants were aged 18-65 with confirmed TB and starting their prescribed treatment. We collected data on socio-demographics and used 13 items to capture the self-, anticipated-, and public-stigma from which we composed the dependent variables. The primary independent variable was sex. We employed multivariable logistic regression analysis to evaluate the association between sex and the three stigma types. Additionally, we considered potential confounders such as age, HIV, and employment status. Statistical significance was defined as p<0.05. Results: In this study we enrolled 144 participants with a mean age of 35.8 years (standard deviation = 12). Half of the participants (50%, n=72) were female, 44% had a secondary education, 37.5% were unemployed, and 32.6% were co-infected with HIV. The prevalence of self-stigma was 71.1%, anticipated stigma was 75.7%, and public stigma was 41.7%. Significant factors were associated with self-stigma were female sex (adjusted odds ratio (AOR): 2.35 95% CI: 1.02-5.74) and unemployment (AOR: 2.95 95% CI: 1.16-8.58). HIV-positive status was significantly associated with anticipated stigma (AOR: 3.58 95% CI: 1.38-11.23). However, none of the variables we evaluated showed a significant association with public stigma. Conclusions: Our study showed a high prevalence of self, anticipated and public stigma among TB patients. Notably, females and unemployed individuals were at a higher risk of self-stigma, while those with HIV/AIDS and TB were more likely to report anticipated stigma. To combat stigma effectively, interventions should be tailored to cater to sex-specific needs and persons living with HIV. Future research should delve further in determinants of TB-related stigma in high-burden settings.

Therapy modulates the response to T cell epitopes over the spectrum of tuberculosis infection.

BACKGROUND: Identifying stage-specific antigens is essential for developing tuberculosis (TB) diagnostics and vaccines. In a low TB endemic country, we characterized, the Mycobacterium tuberculosis (Mtb)-specific immune response to a pool of Mtb-derived epitopes (ATB116), demonstrated as associated with TB disease. METHODS: In this prospective observational cross-sectional study, we enrolled healthy donors (HD), subjects with TB disease, and TB infection (TBI) at baseline and therapy completion. T-cell response after whole blood stimulation with the peptide pools was characterized by ELISA, flow cytometry, and multiplex assay. RESULTS: ATB116-specific IFN-γ response (by ELISA) significantly associates with Mtb regardless of infection/disease (p < 0.0001) and decreases during TB therapy (p = 0.0002). Flow cytometry confirms that ATB116-specific CD4+ T-cell response associated with Mtb regardless of infection/disease (p < 0.0001) and shows a significantly higher frequency of IFN-γ/IL-2 and central memory T-cells in TBI compared to TB (p = 0.016; p = 0.0242, respectively). CD4+ T cell-specific response decreases after TB therapy completion. The antigen-specific CD8+ T-cell response mirrors the CD4+ response. Finally, the multiplex assay analysis showed that ATB116 induces several immune factors in both TB and TBI. CONCLUSION: We characterized the immune response to Mtb peptide pools that is modulated by TB therapy. These results are important for our understanding of TB immunopathogenesis and vaccine design.

A Literature Review on the Adherence to Screening Guidelines for Latent Tuberculosis Infection Among Persons Living With HIV.

Human immunodeficiency virus (HIV) infection increases the risk of reactivation of latent tuberculosis infection (LTBI). Although antiretroviral therapy decreases the progression of LTBI to tuberculosis disease (TBD), persons living with HIV (PLHIV) still have higher risk of TBD compared to the general population. LTBI screening is recommended for all newly diagnosed PLHIV to prevent TBD. However, several studies from low TBD incidence countries have reported sub-optimal implementation of these guidelines. This review aims to assess published studies on adherence to LTBI screening among PLHIV by identifying factors and determinants that affect the implementation of LTBI screening among PLHIV in low TBD incidence countries. Electronic databases were used to search for articles describing the adherence to LTBI screening guidelines. Fourteen studies were included in the final review. Ten studies assessed the frequency of PLHIV getting LTBI screening, and 4 studies assessed the compliance of health care providers in implementing the guidelines. PLHIV who were screened for LTBI ranged from 22.4% to 85%, of which 0.8% to 25.6% had positive results. Only 20% to 57.4% of surveyed physicians implemented the guidelines. Country of birth was an independent predictor of receiving LTBI screening. LTBI screening guidelines are inconsistently performed resulting in missed opportunities for TBD prevention. A comprehensive screening policy involving testing all PLHIV may be the best approach, rather than a targeted approach testing foreign-born individuals only. This will minimize missing domestic cases that can worsen disparity in HIV and tuberculosis infection among minority groups, including Asians, Native Hawaiians, and Pacific Islanders.

Safety and Tolerability of Six Months of Isoniazid Plus Pyridoxine or Three Months of Rifampicin for Tuberculosis among Subjects with Diabetes Mellitus: A Randomized Trial.

Tuberculosis (TB) associated with diabetes mellitus (DM) is a growing problem, particularly in low- and medium-resource countries. We conducted an open-label, parallel-group, randomized, and controlled trial in a tertiary care center in Mexico City to assess TB preventive treatment (TPT) with isoniazid (INH) or rifampicin (RIF) in people with type 2 DM. Participants were assigned six months of INH 300 mg/day plus pyridoxine 75 mg or three months of RIF 600 mg/day. The primary outcomes were adverse events resulting in permanent treatment cessation and considered possibly or probably related to study drugs. We included 130 subjects, 68 randomized to INH and 62 to RIF. We prematurely halted the study based on recommendations of the Adverse Event Safety Panel. There was no difference between arms in the overall frequency of adverse events. However, the INH group had significantly more permanent treatment interruptions due to grade 2 recurrent or grade 3 or 4 hepatoxicity. In comparison, the RIF arm had more treatment interruptions due to grade 3 or 4 gastrointestinal intolerance. TPT using INH or RIF is not safe enough to be considered a universal indication to patients with type 2 DM and TB infection. These results underline the need to search for alternative TB preventions with better safety profiles for type 2 DM patients.

Update on the diagnosis and treatment of tuberculosis.

According to World Health Organization estimates, more than 1 million patients aged less than 15 years develop tuberculosis (TB) each year worldwide. In some regions, up to 25% of new TB cases are caused by drug-resistant strains. Although Spain is considered a low-incidence country, several hundred children and adolescents develop TB each year. The importance of paediatric TB has been minimized for years due to the lack of microbiological confirmation in many patients and because these patients are not usually contagious. Nevertheless, in the past 15 years there have been major improvements in the epidemiological reporting of TB in children and adolescents, new immunodiagnostic tests have been developed, molecular methods that allow rapid microbiological diagnosis and detection of variants associated with drug resistance have become available, novel second-line antituberculosis drugs have been discovered, including for paediatric use, and the results of clinical trials have validated shorter courses of treatment for some patients. This document, developed by a group of experts from the Sociedad Española de Infectología Pediátrica and the Sociedad Española de Neumología Pediátrica, updates and complements the previous guidelines for the diagnostic and therapeutic management of children with TB in Spain based on the newly available scientific evidence.

Spoligotyping of Mycobacterium tuberculosis isolates from Pulmonary Tuberculosis patients from North Karnataka, India.

Tuberculosis (TB) is a leading cause of morbidity and mortality in low income countries. Multi-drug resistant (MDR-TB) is seen as the reason for many TB outbreaks globally and is also a threat to control programmes. India accounts for 27% TB cases worldwide. Our study was undertaken to understand the outbreaks related to MTB. All the sputum samples were subjected to microscopy and smear positive samples were cultured on Lowenstein-Jensen (L-J) media. Identification was carried by biochemical analysis. A total of 57 isolates were subjected to Drug Susceptibility testing (DST) and spoligotyping, where eleven MDR-TB isolates were confirmed, of which ten were SIT1/Beijing and one SIT53/T1. Spoligotyping results showed that the predominant lineage in this region was SIT1/Beijing followed by SIT124/U and the strains which did not match spoligodatabase were named as orphans. In this study, MDR-TB was associated with SIT1/Beijing and mono resistance belonged to CAS1_DEL.

Differential expression of maturation and activation markers on NK cells in patients with active and latent tuberculosis.

NK cells were recently suggested to be important for the initial control of M. tuberculosis infection. The phenotypes of the 3 main NK blood subsets, CD56bright , CD56dim , and CD56neg cells, were characterized by flow cytometry in a cohort of 81 prospectively enrolled subjects (21 untreated patients with active tuberculosis -aTB-, 35 latently TB infected -LTBI- subjects, and 25 non-infected controls), using 9 different mAbs added to whole blood. Compared to LTBI subjects, patients with aTB had lower proportions of total NK cells, lower proportions and numbers of CD56neg cells expressing early maturation markers (CD161, NKp30, NKp46), but higher density of NKp30 and NKp46 expression on both CD56neg and CD56dim subsets, associated with higher expression of granzymes A/B. They also had higher proportions of activated CD69pos cells within all 3 NK cell subsets and, the percentage of CD69pos CD56dim cells among CD69pos and/or NKG2Cpos NK cells was identified as a potential biomarker to discriminate aTB from LTBI. LTBI subjects were in contrast characterized by higher expression of late maturation markers (CD57, KIR molecules) on the CD56neg subset, by higher proportions of NKG2Cpos KIRpos CD56dim NK cells, and by higher in vitro IFN-γ production than patients with aTB. Thus, the in-depth phenotypic characterization of blood NK cell subsets provides new insights on possible functional modifications and the potential role of NK cells in the control of M. tuberculosis infection in humans.

Peripheral Blood Markers Correlate with the Progression of Active Tuberculosis Relative to Latent Control of Mycobacterium tuberculosis Infection in Macaques.

Despite a century of research into tuberculosis (TB), there is a dearth of reproducible, easily quantifiable, biomarkers that can predict disease onset and differentiate between host disease states. Due to the challenges associated with human sampling, nonhuman primates (NHPs) are utilized for recapitulating the closest possible modelling of human TB. To establish a predictive peripheral biomarker profile based on a larger cohort of rhesus macaques (RM), we analyzed results pertaining to peripheral blood serum chemistry and cell counts from RMs that were experimentally exposed to Mtb in our prior studies and characterized as having either developed active TB (ATB) disease or latent TB infection (LTBI). We compared lung CFU burdens and quantitative pathologies with a number of measurables in the peripheral blood. Based on our results, the investigations were then extended to the study of specific molecules and cells in the lung compartments of a subset of these animals and their immune responses. In addition to the elevated serum C-reactive protein (CRP) levels, frequently used to discern the level of Mtb infection in model systems, reduced serum albumin-to-globulin (A/G) ratios were also predictive of active TB disease. Furthermore, higher peripheral myeloid cell levels, particularly those of neutrophils, kynurenine-to-tryptophan ratio, an indicator of induced expression of the immunosuppressive molecule indoleamine dioxygenase, and an influx of myeloid cell populations could also efficiently discriminate between ATB and LTBI in experimentally infected macaques. These quantifiable correlates of disease were then used in conjunction with a regression-based analysis to predict bacterial load. Our results suggest a potential biomarker profile of TB disease in rhesus macaques, that could inform future NHP-TB research. Our results thus suggest that specific biomarkers may be developed from the myeloid subset of peripheral blood or plasma with the ability to discriminate between active and latent Mtb infection.