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Background: Identification of non-sputum diagnostic markers for tuberculosis (TB) is urgently needed. This exploratory study aimed to discover potential serum protein biomarkers for the diagnosis of active pulmonary TB (PTB)., Method: We employed Proximity Extension Assay (PEA) to measure levels of 92 protein biomarkers related to inflammation in serum samples from three patient groups: 30 patients with active PTB, 29 patients with other respiratory diseases with latent TB (ORD with LTBI+), and 29 patients with other respiratory diseases without latent TB (ORD with LTBI-). To understand the functional mechanisms associated with differentially expressed proteins, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Least absolute shrinkage and selection operator (LASSO) regression was employed to identify potential TB diagnostic protein biomarkers. Network interactions among the identified candidate diagnostic markers were then analyzed, and their diagnostic performance was evaluated using logistic regression and receiver operating characteristic (ROC) analysis., Result: The analysis revealed 37 differentially expressed proteins (DEPs) in the active PTB group compared to both ORD with LTBI + and ORD with LTBI- groups. Gene Ontology analysis indicated that these DEPs were primarily involved in the inflammatory response, while KEGG enrichment analysis highlighted the cytokine-cytokine receptor interaction pathway as the top significant hit. LASSO regression identified eight promising candidate protein biomarkers: IFN-gamma, LIF, uPA, CSF-1, SCF, SIRT2, 4E-BP1, and GDNF. The combined set of these eight proteins yielded an AUC of 0.943 for differentiating active PTB from ORD with LTBI+, and an AUC of 0.927 for distinguishing PTB from ORD with LTBI-., Conclusion: We have identified eight protein markers that reliably differentiate active PTB from ORD irrespective of LTBI presence. Further large-scale validation and translation of these protein markers into a user-friendly and affordable point-of-care test hold the potential to significantly enhance TB control in high-burden regions., Competing Interests: Declarations. Ethics approval and consent to participate: Written informed consent was obtained from all the study participants. The study was approved by the Armauer Hansen Research Institute /All Africa Leprosy Rehabilitation and Training Center (AHRI/ALERT) Ethics Review Committee (AAERC) (P021/16). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Tuberculosis (TB) and HIV co-infections are extensively overlapping, especially in developing countries. HIV infection is known as a major risk factor for the reactivation of latent TB into active TB. Although not fully understood and needs further study, HIV infection might enhance the reactivation of latent TB by breaching immune control mechanisms. We investigated the influence of HIV infection on the cytokine response of LTB-infected individuals. Heparinized venous blood was collected from 40 ART-naïve HIV-infected and 30 HIV-negative healthy controls for LTB screening, plasma collection, and PBMC isolation and stimulation. The level of cytokines in plasma and their production by PBMCs stimulated with purified protein derivative (PPD), staphylococcus enterotoxin B (SEB), or unstimulated PBMCs were analyzed using a cytometric bead array (CBA) assay. PPD-induced IL-2 by PBMCs was higher in LTB-infected groups compared with HIV-negative LTB-negative groups (p = 0.0015). When LTB-infected groups were co-infected with HIV (HIV+LTB+), the IL-2 (p < 0.0001) and IFN-gamma (p = 0.0144) production by PPD-stimulated PBMCs was reduced. The level of IL-2 (p = 0.0070), IL-6 (p = 0.0054), and TNF-alpha (p = 0.0045) in plasma were lower in HIV+LTB+ individuals compared with HIV-negative LTB-positive (HIV-LTB+) groups. Our findings suggested that HIV co-infection in LTB-positive individuals is associated with the diminished production of PPD-induced Th1 (IFN-gamma and IL-2) cytokines by PBMCs and in the plasma level of IL-2 and proinflammatory cytokines (IL-6 and TNF-alpha)., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Girmay et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Dormancy survival regulator (DosR) and resuscitation-promoting factor (Rpf) antigens of Mycobacterium tuberculosis are activated during dormant phase of tuberculosis (TB). This study evaluates the differential immunogenicity potentials of DosR and Rpf antigens in individuals with latent tuberculosis infection (LTBI) and active TB patients., Methods: After a literature search in electronic databases, studies were selected by following precise eligibility criteria. Outcomes were synthesized systematically, and meta-analyses were performed to estimate standardized mean differences (SMDs) in interferon-gamma (IFNγ) levels, and IFNγ positive immune cells between individuals with LTBI and active TB patients., Results: Twenty-six studies (1278 individuals with LTBI and 1189 active TB patients) were included. DosR antigens Rv0569 (Standardized mean difference; SMD 2.44 [95%CI: 1.21, 3.66]; p < 0.0001), Rv1733c (SMD 0.60 [95%CI: 0.14, 1.07]; p = 0.011), Rv1735c (SMD 1.16 [95%CI: 0.44, 1.88]; p = 0.002), Rv1737c (SMD 1.26 [95%CI: 0.59, 1.92]; p < 0.0001), Rv2029c (SMD 0.89 [95%CI: 0.35, 1.42]; p = 0.002), RV2626c (SMD 1.24 [95%CI: 0.45, 2.02); p = 0.002), and Rv2628 (SMD 0.65 [95%CI: 0.38, 0.91]; p < 0.0001) and Rpf antigens Rv0867c (SMD 1.33 [95%CI: 0.48, 2.18]; p = 0.002), Rv1009 (SMD 0.65 [95%CI: 0.05, 1.25]; p = 0.034), and Rv2450c (SMD 1.54 [95%CI: 0.92, 2.16]; p < 0.0001) elicited higher IFNγ levels in individuals with LTBI in comparison with active TB patients. IFNγ-positive immunoresponsive cells were significantly higher in individuals with LTBI than in active TB patients for antigens Rv1733c (SMD 1.02 [95%CI: 0.15, 1.88]; p = 0.021), Rv2029c (SMD 0.57 [95%CI: 0.05, 1.09]; p = 0.031), and Rv2628 [SMD 0.38 [95%CI: 0.15, 0.61]; p = 0.001)., Conclusion: DosR antigens Rv0569, Rv1733c, Rv1735c, Rv1737c, RV2626c, Rv2628, and Rv2029c, and Rpf antigens Rv0867c, Rv1009, and Rv2450c are found to elicit immune responses differently in individuals with LTBI and active TB patients., (© 2024. The Author(s).)

Diabetes mellitus (DM) is predisposing to the development of latent tuberculosis infection (LTBI). An understanding of the underlying factors of LTBI-DM is important for tuberculosis prevention and control. This study aims to evaluate the association between LTBI and DM among the noninstitutionalized civilian population in the United States, focusing on the impact of serum globulins. We performed a cross-sectional study design using public data from 2011 to 2012 National Health and Nutrition Examination Survey, focusing on participants diagnosed with LTBI who were aged 20 and above. Weighted Wilcoxon rank-sum and weighted chi-square tests were used to compare group differences. A multivariable logistic regression model was constructed to assess the association between serum globulin and DM, with subgroup analyses and evaluations of nonlinear relationships. Receiver operating characteristic curves were used to assess the predictive power of the models. A total of 694 participants (512 DM and 182 nonDM) were included in our study and the incidence of DM was 22%. Higher serum globulin levels were significantly associated with an increased risk of DM, with a 21% increase in risk for each unit increase in serum globulin (odds ratio = 1.21, 95% confidence interval [1.03, 1.43], P < .001). The relationship between serum globulin and DM was linear, and higher serum globulin levels were associated with a higher risk of DM, particularly in males (P = .043) and obese individuals (P = .019). The area under the curve for serum globulin predicting DM was 0.795, with an optimal cutoff value of 2.9. Elevated serum globulin levels are significantly associated with an increased risk of DM among individuals with LTBI, highlighting the potential role of serum globulin as a predictive biomarker for DM in this population. However, the specific mechanism between globulin and LTBI-DM needs to be further investigated., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Interferon-gamma release assay (IGRA) for tuberculosis (TB) remains limited in its ability to discriminate between active TB (ATB) and latent TB infection (LTBI). Activation markers on host T and NK cells are currently considered to be promising markers in the diagnosis of ATB., Methods: This prospective observational study enrolled 213 participants and the participants were divided into ATB, LTBI, other lung-related diseases (ORD), and health control (HC) groups. CD69 and HLA-DR on T and NK cells were detected in QFT-TB assay, and a composite scoring system (TB-Flow) was created for the diagnosis of ATB., Results: The expression of activation markers (CD69 and HLA-DR) were significantly increased in ATB. HLA-DR on NK cells, CD69 on T cells, and QFT-TB in the differential diagnosis of ATB and HC were all of good diagnostic value (AUC>0.90). In addition, the TB-Flow greatly improved the efficiency of differential diagnosis between ATB and LTBI (AUC=0.90, 95%CI: 0.84-0.96), with sensitivity and specificity of 79.17 % (95%CI: 64.60%-89.04 %) and 88.68 % (95%CI: 76.28%-95.31 %)., Conclusions: CD69 and HLA-DR on host T and NK cells are promising markers in distinguishing different TB infection status. Our blood-based TB-Flow scoring system can distinguish ATB from LTBI with good diagnostic efficacy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The associations between blood heavy metal levels and latent tuberculosis infection (LTBI) have not been fully elucidated. The aim of this study was to investigate the potential association between blood heavy metal levels and LTBI in adults using National Health and Nutrition Examination Survey data from 2011 to 2012., Methods: We enrolled 1710 participants in this study, and compared the baseline characteristics of participants involved. Multivariate logistic regression analysis, restricted cubic splines (RCS) analysis, along with subgroup analysis and interaction tests were utilized to explore the association between blood manganese (Mn) level and LTBI risk., Results: Participants with LTBI had higher blood Mn level compared to non-LTBI individuals ( p < 0.05), while the levels of lead, cadmium, total mercury, selenium, copper, and zinc did not differ significantly between the two groups ( p > 0.05). In the fully adjusted model, a slight increase in LTBI risk was observed with each 1-unit increase in blood Mn level (OR = 1.00, 95% CI: 1.00-1.01, p  = 0.02). Participants in the highest quartile of blood Mn level had a threefold increase in LTBI risk compared to those in the lowest quartile (OR = 4.01, 95% CI: 1.22-11.33, p  = 0.02). RCS analysis did not show a non-linear relationship between blood Mn level and LTBI (non-linear p -value = 0.0826). Subgroup analyses and interaction tests indicated that age, alcohol consumption, and income-to-poverty ratio significantly influenced LTBI risk (interaction p -values<0.05)., Conclusion: Individuals with LTBI had higher blood Mn level compared to non-LTBI individuals, and higher blood Mn level associated with increased LTBI risk., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Qi, Zhang and He.)

The World Health Organization End TB strategy aims for a 90% reduction of tuberculosis (TB) incidence by 2035. Systematic testing and treatment of latent TB infection (LTBI) among contacts of active TB patients is recommended as one of the ways to curtail TB incidence. However, there is a shortage of tools to accurately diagnose LTBI. We assessed the appropriateness of whole blood host transcriptomic markers (TM) to diagnose LTBI among household contacts of bacteriologically confirmed index cases compared to HIV negative healthy controls (HC). QuantiFERON-TB Gold Plus Interferon gamma release assay (IGRA) and reverse-transcriptase quantitative PCR were used to determine LTBI and quantify TM expression respectively. Association between TM expression and LTBI was evaluated by logistic regression modelling. A total of 100 participants, 49 TB exposed (TBEx) household contacts and 51 HC, were enrolled. Twenty-five (51%) TBEx individuals tested positive by IGRA, and were denoted as LTBI individuals, and 37 (72.5%) HC were IGRA-negative. Expression of 11 evaluated TM was significantly suppressed among LTBI compared to HC. Out of the 11 TM, ZNF296 and KLF2 expression were strongly associated with LTBI and successfully differentiated LTBI from HC. Paradoxically, 21 (49%) TBEx participants who tested IGRA negative exhibited the same pattern of suppressed TM expression as IGRA positive (LTBI-confirmed individuals). Results suggest that suppression of gene expression underlies LTBI and may be a more sensitive diagnostic biomarker than standard-of-care IGRA., (© 2024. The Author(s).)

Objective: To analyse the expression profiles of serum exosome tRFs/tiRNAs and to explore their diagnostic value in tuberculosis (TB) activity., Methods: The serum exosome tRF/tiRNA profile was analysed using high-throughput sequencing technology in 5 active tuberculosis (ATB) patients, 5 latent tuberculosis infection (LTBI) patients and 5 healthy controls (HCs). Then, serum exosome tRFs/tiRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR), and their diagnostic value was evaluated by receiver operating characteristic curve (ROC) and area under the curve (AUC). Finally, bioinformatics analysis was performed to explore and identify the potential biological pathways induced by tRFs/tiRNAs., Results: The sequencing results revealed that serum exosome tRF/tiRNA expression profiles were different among ATB patients, LTBI patients and HCs. Three tRFs (tRF-56:75-Trp-CCA-4, tRF-1:22-chrM.Ser-GCT and tRF-56:76-Val-TAC-1-M2) were selected for qRT-PCR validation. The results demonstrated that the expression level of tRF-1-22-chrM.Ser-GCT was upregulated in ATB patients, while tRF-56-75-Trp-CCA-4 was downregulated, which was consistent with the sequencing data. The AUCs of tRF-56:75-Trp-CCA-4 and tRF-1:22-chrM. Ser-GCT were 0.824 and 1.000, respectively, which have significant values in the diagnosis of ATB patients. Moreover, the expression levels of tRF-56:75-Trp-CCA-4 and tRF-1:22-chrM.Ser-GCT and tRF-56:76-Val-TAC-1-M2 in ATB patients and LTBI were different, which indicated that these three tRFs could effectively distinguish ATB patients and LTBI patients., Conclusion: Our findings indicate that serum exosome tRFs can be used as potential markers for the diagnosis of ATB and LTBI., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Tuberculosis (TB) is still the main cause of mortality due to a single transfectant, Mycobacterium tuberculosis (MTB). Latent tuberculosis infection (LTBI) is a condition characterized by the presence of tuberculosis (TB) that is not clinically apparent but nonetheless shows a sustained response to MTB. Presently, tuberculin skin test (TST) and interferon gamma (IFN-γ) release assays (IGRAs) are mainly used to detect LTBI via cell-mediated immunity of T-cells. For people with end-stage renal disease (ESRD), the diagnosis of patients infected with MTB is difficult because of T-cell dysfunction. To get more accurate diagnosis results of LTBI, it must compensate for the deficiency of IGRA tests., Methods: Sixty-seven hemodialysis (HD) patients and 96 non-HD patients were enrolled in this study and the study population is continuously included. IFN-γ levels were measured by the QuantiFERON-TB Gold In-Tube (QFT-GIT) test. Kidney function indicators, blood urea nitrogen (BUN), serum creatinine (Cr), and estimated glomerular filtration rate (eGFR) were used to compensate for the declined IFN-γ levels in the IGRA test., Results: In individuals who were previously undetected, the results of compensation with serum Cr increased by 10.81%, allowing for about 28% more detection, and compensation with eGFR increased by 5.41%, allowing for approximately 14% more detectable potential among them and employing both of them could enhance the prior shortcomings of IGRA tests. when both are used, the maximum compensation results show a sensitivity increase rate of 8.81%, and approximately 23% of patients who were previously undetectable may be found., Conclusion: Therefore, the renal function markers which are routine tests for HD patients to compensate for the deficiency of IGRA tests could increase the accuracy of LTBI diagnosis.

Introduction: There is no useful method to discriminate between latent tuberculosis infection (LTBI) and active pulmonary tuberculosis (PTB). This study aimed to investigate the potential of cytokine profiles to discriminate between LTBI and active PTB using whole-blood stimulation with Mycobacterium tuberculosis (MTB) antigens, including latency-associated antigens., Materials and Methods: Patients with active PTB, household contacts of active PTB patients and community exposure subjects were recruited in Manila, the Philippines. Peripheral blood was collected from the participants and used for whole-blood stimulation (WBS) with either the early secretory antigenic target and the 10-kDa culture filtrate protein (ESAT-6/CFP-10), Rv3879c or latency-associated MTB antigens, including mycobacterial DNA-binding protein 1 (MDP-1), α-crystallin (Acr) and heparin-binding hemagglutinin (HBHA). Multiple cytokine concentrations were analyzed using the Bio-Plex™ multiplex cytokine assay., Results: A total of 78 participants consisting of 15 active PTB patients, 48 household contacts and 15 community exposure subjects were eligible. The MDP-1-specific IFN-γ level in the active PTB group was significantly lower than that in the household contact group (p < 0.001) and the community exposure group (p < 0.001). The Acr-specific TNF-α and IL-10 levels in the active PTB group were significantly higher than those in the household contact (TNF-α; p = 0.001, IL-10; p = 0.001) and community exposure (TNF-α; p < 0.001, IL-10; p = 0.01) groups. However, there was no significant difference in the ESAT-6/CFP-10-specific IFN-γ levels among the groups., Conclusion: The patterns of cytokine profiles induced by latency-associated MTB antigens using WBS have the potential to discriminate between LTBI and active PTB. In particular, combinations of IFN-γ and MDP-1, TNF-α and Acr, and IL-10 and Acr are promising. This study provides the first demonstration of the utility of MDP-1-specific cytokine responses in WBS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Yasuda, Saludar, Sayo, Suzuki, Yokoyama, Ozeki, Kobayashi, Nishiyama, Matsumoto, Cox, Tanaka and Yamashita.)

Background: Tuberculosis (TB) is caused by Mycobacterium tuberculosis (Mtb) and kills more than 1.5 million people each year., Methods: We examine the frequency and function of NK cells in the blood and airways over the course of Mtb infection in a TB macaque model and demonstrate differences in NK marker expression between the two compartments. Flow cytometry and intracellular cytokine staining were utilized to identify NK cell subsets (expressing NKG2A, CD56, or CD16) and function (IL-10, TNF, IL-2, IFN-g, IL-17, and CD107a)., Results: Blood and airway NK cell frequencies were similar during infection though there were differences in subset populations between blood and airway. Increased functional (cytokine/CD107a) parameters were observed in airway NK cells during the course of infection while none were seen in the blood., Conclusions: This study suggests that NK cells in the airway may play an important role in TB host response., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

IL-38 is a recently discovered, novel anti-inflammatory cytokine, which belongs to the IL-1β family. The role played by this cytokine in diabetes-tuberculosis nexus is not known. Serum levels of IL-38, TNF-α, IL-6, and IL-1β in Normal Glucose Tolerance (NGT) and chronic Diabetes (DM) subjects, both with and without latent tuberculosis (LTB) (n = 256) were quantified by ELISA. While, serum levels of IL-38 were significantly reduced, the levels of TNF-α, IL-6, and IL-1β were not altered, in LTB infected diabetes patients. While no significant secretion of IL-38 was detected in the quantiferon supernatant, secretion of TNF-α, IL-6, and IL-1β was significantly reduced in LTB infected diabetes patients. The decreased systemic levels of IL-38 and reduced in vitro secretion of other pro-inflammatory cytokines might represent a crucial pathway associated with diabetes-tuberculosis nexus., (Copyright © 2022 Elsevier Inc. All rights reserved.)

SARS-CoV-2 and latent Mycobacterium tuberculosis infection are both highly co-prevalent in many parts of the globe. Whether exposure to SARS-CoV-2 influences the antigen specific immune responses in latent tuberculosis has not been investigated. We examined the baseline, mycobacterial antigen and mitogen induced cytokine and chemokine responses in latent tuberculosis (LTBI) individuals with or without SARS-CoV-2 seropositivity, LTBI negative individuals with SARS-CoV-2 seropositivity and healthy control (both LTBI and SARS-CoV-2 negative) individuals. Our results demonstrated that LTBI individuals with SARS-CoV-2 seropositivity (LTBI+/IgG +) were associated with increased levels of unstimulated and TB-antigen stimulated IFNγ, IL-2, TNFα, IL-17, IL-1β, IL-6, IL-12, IL-4, CXCL1, CXCL9 and CXCL10 when compared to those without seropositivity (LTBI+/IgG-). In contrast, LTBI+/IgG+ individuals were associated with decreased levels of IL-5 and IL-10. No significant difference in the levels of cytokines/chemokines was observed upon mitogen stimulation between the groups. SARS-CoV-2 seropositivity was associated with enhanced unstimulated and TB-antigen stimulated but not mitogen stimulated production of cytokines and chemokines in LTBI+ compared to LTBI negative individuals. Finally, most of these significant differences were not observed when LTBI negative individuals with SARS-CoV-2 seropositivity and controls were examined. Our data clearly demonstrate that both baseline and TB - antigen induced cytokine responses are augmented in the presence of SARS-CoV-2 seropositivity, suggesting an augmenting effect of prior SARS-CoV-2 infection on the immune responses of LTBI individuals., (Copyright © 2021. Published by Elsevier Ltd.)

Although only a small fraction will ever develop the active form of tuberculosis (ATB) disease, chemoprophylaxis treatment in latent TB infected (LTBI) individuals is an effective strategy to control pathogen transmission. Characterizing immune responses in LTBI upon chemoprophylactic treatment is important to facilitate treatment monitoring, and thus improve TB control strategies. Here, we studied changes in the blood transcriptome in a cohort of 42 LTBI and 8 ATB participants who received anti-TB therapy. Based on the expression of previously published gene signatures of progression to ATB, we stratified the LTBI cohort in two groups and examined if individuals deemed to be at elevated risk of developing ATB before treatment (LTBI-Risk) differed from others (LTBI-Other). We found that LTBI-Risk and LTBI-Other groups were associated with two distinct transcriptomic treatment signatures, with the LTBI-Risk signature resembling that of treated ATB patients. Notably, overlapping genes between LTBI-Risk and ATB treatment signatures were associated with risk of progression to ATB and interferon (IFN) signaling, and were selectively downregulated upon treatment in the LTBI-Risk but not the LTBI-Other group. Our results suggest that transcriptomic reprogramming following treatment of LTBI is heterogeneous and can be used to distinguish LTBI-Risk individuals from the LTBI cohort at large., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: There is an urgent medical need to differentiate active tuberculosis (ATB) from latent tuberculosis infection (LTBI) and prevent undertreatment and overtreatment. The aim of this study was to identify biomarker profiles that may support the differentiation between ATB and LTBI and to validate these signatures., Materials and Methods: The discovery cohort included adult individuals classified in four groups: ATB (n = 20), LTBI without prophylaxis (untreated LTBI; n = 20), LTBI after completion of prophylaxis (treated LTBI; n = 20), and healthy controls (HC; n = 20). Their sera were analyzed for 40 cytokines/chemokines and activity of adenosine deaminase (ADA) isozymes. A prediction model was designed to differentiate ATB from untreated LTBI using sparse partial least squares (sPLS) and logistic regression analyses. Serum samples of two independent cohorts (national and international) were used for validation., Results: sPLS regression analyses identified C-C motif chemokine ligand 1 (CCL1), C-reactive protein (CRP), C-X-C motif chemokine ligand 10 (CXCL10), and vascular endothelial growth factor (VEGF) as the most discriminating biomarkers. These markers and ADA(2) activity were significantly increased in ATB compared to untreated LTBI (p ≤ 0.007). Combining CCL1, CXCL10, VEGF, and ADA2 activity yielded a sensitivity and specificity of 95% and 90%, respectively, in differentiating ATB from untreated LTBI. These findings were confirmed in the validation cohort including remotely acquired untreated LTBI participants., Conclusion: The biomarker signature of CCL1, CXCL10, VEGF, and ADA2 activity provides a promising tool for differentiating patients with ATB from non-treated LTBI individuals., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer HD declared a past co-authorship with the authors SJ and TO to the handling editor., (Copyright © 2021 Delemarre, van Hoorn, Bossink, Drylewicz, Joosten, Ottenhoff, Akkerman, Goletti, Petruccioli, Navarra, van den Broek, Paardekooper, van Haeften, Koenderman, Lammers, Thijsen, Hofland and Nierkens.)

Background: HIV-exposed uninfected (HEU) infants have increased risk of tuberculosis (TB). Testing for Mycobacterium tuberculosis (Mtb) infection is limited by reduced Quantiferon (QFT) sensitivity in infants and tuberculin skin test (TST) cross-reactivity with Bacillus Calmette-Guérin vaccine. Our objective is to assess if non-IFNγ cytokine responses to Mtb-specific antigens have improved sensitivity in detecting Mtb infection in HEU infants compared with QFT., Methods: HEU infants were enrolled in a randomized clinical trial of isoniazid preventive therapy (IPT) to prevent Mtb infection in Kenya (N = 300) and assessed at 12 months postrandomization (14 months of age) by TST and QFT-Plus. Non-IFNγ cytokine secretion (IL2, TNF, IP10, N = 229) in QFT-Plus supernatants was measured using Luminex assay. Logistic regression was used to assess the effect of IPT on Mtb infection outcomes in HEU infants., Results: Three of 251 (1.2%) infants were QFT-Plus positive. Non-IFNγ Mtb antigen-specific responses were detected in 12 additional infants (12/229, 5.2%), all TST negative. IPT was not associated with Mtb infection defined as any Mtb antigen-specific cytokine response (odds ratio = 0.7, P = 0.54). Mtb antigen-specific IL2/IP10 responses had fair correlation (τ = 0.25). Otherwise, non-IFNγ cytokine responses had minimal correlation with QFT-Plus and no correlation with TST size., Conclusions: We detected non-IFNg Mtb antigen-specific T-cell responses in 14-month HEU infants. Non-IFNg cytokines may be more sensitive than IFNg in detecting infant Mtb infection. IPT during the first year of life was not associated with Mtb infection measured by IFNg, IL2, IP10 and TNF Mtb-specific responses., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

CXCL17 is a novel mucosal chemokine that mediates myeloid cell recruitment and bactericidal activity and highly expressed in the respiratory tract. However, its role in tuberculosis (TB) immunopathogenesis or protection remains unknown. In this study, we evaluated the function of CXCL17 in a mouse model of aerosol infection with the clinical W-Beijing lineage Mycobacterium tuberculosis hypervirulent HN878 strain. Our results show that CXCL17 production increases in the lung of M. tuberculosis -infected mice during acute and chronic stages of infection. Moreover, in vitro M. tuberculosis infection of epithelial cells and myeloid cells induces production of CXCL17. In humans, lower serum CXCL17 levels are observed among active pulmonary TB patients when compared with subjects with latent TB infection and healthy controls, suggesting a protective role. However, mice treated with rCXCL17 show similar lung bacterial burden and inflammation compared with control animals, despite an increased lung myeloid cell accumulation. Finally, CXCL17 -/- mice are not more susceptible to TB than wild-type animals. These findings suggest that CXCL17 is induced in both murine epithelial and myeloid cells upon M. tuberculosis infection and increased expression during human latent TB infection. However, CXCL17 may have a dispensable role during pulmonary TB., (Copyright © 2021 The Authors.)

This study was aimed at exploring whether latent tuberculosis infection (LTBI) contributes to the pathogenesis of immune-mediated inflammatory diseases in a TB endemic setting. We screened 198 rheumatoid arthritis (RA) patients with tuberculin skin test (TST) and studied 61 (median DAS28-ESR = 6.3) who were positive. Whole blood T cell proliferative responses to Mycobacterium tuberculosis (Mtb) membrane (MtM) antigens, including the latency-induced protein alpha crystallin (Acr), were determined by flow cytometry using Ki67 expression as the marker for nuclear proliferation. Serum antibody levels were determined by ELISA. Follow-up investigations (at 3-6, 9-12 and 15-18 months after baseline) were performed in 41 patients who were classified empirically as 'high' (HR-T/HR-B) or 'low' (LR-T/LR-B) responders based on their dynamic T cell or antibody responses. Significant correlations were seen between baseline T cell responses to MtM and Acr, and between IgG, IgA and IgM antibody responses to MtM. However, no correlation was seen between T and B cell responses. At all time points during the follow-up, T cell responses to both antigens (except for MtM at one point) were significantly higher in HR-T (n = 25) than LR-T (n = 16) patients. Levels of IgA and IgM (but not IgG) antibodies to MtM were also significantly higher in HR-B (n = 13) than LR-B (n = 28) at all time points. Importantly, HR-T patients exhibited significantly higher baseline and follow-up DAS28 scores than LR-T. Ten (of 61) patients had a history of TB and developed RA 6 years (median) after contracting TB. Three new TB cases (1 from TST-positive and 2 from TST-negative groups) emerged during the follow-up. Our results suggest that persistently elevated T cell responses to Mtb antigens may contribute to disease activity in RA., Competing Interests: The authors have declared that no competing interests exist.

Background: Vitamin D is essential in the host defense against tuberculosis (TB). Suboptimal vitamin D status is common in the hemodialysis population. Hemodialysis patients have an increased risk compared to the general population latent tuberculosis infection (LTBI). However, the association between vitamin D deficiency and LTBI in this population remains unclear., Materials and Methods: We conducted a cross-sectional study between March and May 2017. Interferon-gamma release assay (IGRA) through QuantiFERON-TB Gold In-Tube was used to assess LTBI. Plasma 25-hydroxycholecalciferol (25-OHD) levels were measured by Elecsys Vitamin D Total assay. Suboptimal vitamin D levels included vitamin D insufficiency 20-29 ng/mg and vitamin D deficiency <20 ng/mL. Predictors for LTBI were analyzed., Results: A total of 287 participants were enrolled. The suboptimal vitamin D level was 31.4% (90/287), which including the vitamin D deficiency was 13.9% (40/287). A total of 49.1% (141/287) people received nutritional vitamin D supplementation. The prevalence of IGRA positivity in this study was 25.1% (72/287). There was no significant difference in vitamin D concentrations or the proportion of vitamin D supplementation among the IGRA-positive and IGRA-negative groups (p = 0.789 and 0.496, respectively). In multivariate analysis, age >65 years old (odds ratio (OR), 1.89; 95% CI, 1.08-3.31; p = 0.026) and TB history (OR, 3.51; 95% CI, 1.38-8.91; p = 0.008) were independent predictors of IGRA positivity., Conclusion: This is the first study to report that vitamin D deficiency was not associated with IGRA positivity in a hemodialysis population. Aging and TB history were both independent predictors for LTBI., Competing Interests: Declaration of Competing Interest All authors have no conflicts of interest to declare., (Copyright © 2020. Published by Elsevier B.V.)

Bacterial culture of M. tuberculosis (MTB), the causative agent of tuberculosis (TB), from clinical specimens is the gold standard for laboratory diagnosis of TB, but is slow and culture-negative TB cases are common. Alternative immune-based and molecular approaches have been developed, but cannot discriminate between active TB (ATB) and latent TB (LTBI). Here, to identify biomarkers that can discriminate between ATB and LTBI/healthy individuals (HC), we profiled 116 serum samples (HC, LTBI and ATB) using a protein microarray containing 257 MTB secreted proteins, identifying 23 antibodies against MTB antigens that were present at significantly higher levels in patients with ATB than in those with LTBI and HC (Fold change > 1.2; p < 0.05). A 4-protein biomarker panel (Rv0934, Rv3881c, Rv1860 and Rv1827), optimized using SAM and ROC analysis, had a sensitivity of 67.3% and specificity of 91.2% for distinguishing ATB from LTBI, and 71.2% sensitivity and 96.3% specificity for distinguishing ATB from HC. Validation of the four candidate biomarkers in ELISA assays using 440 serum samples gave consistent results. The promising sensitivity and specificity of this biomarker panel suggest it merits further investigation for its potential as a diagnostic for discriminating between latent and active TB., (© 2021. The Author(s).)

There is a crucial need for non-sputum-based TB tests. Here, we evaluate the performance of RISK6, a human-blood transcriptomic signature, for TB screening, triage and treatment monitoring. RISK6 performance was also compared to that of two IGRAs: one based on RD1 antigens (QuantiFERON-TB Gold Plus, QFT-P, Qiagen) and one on recombinant M. tuberculosis HBHA expressed in Mycobacterium smegmatis (IGRA-rmsHBHA). In this multicenter prospective nested case-control study conducted in Bangladesh, Georgia, Lebanon and Madagascar, adult non-immunocompromised patients with bacteriologically confirmed active pulmonary TB (ATB), latent TB infection (LTBI) and healthy donors (HD) were enrolled. ATB patients were followed-up during and after treatment. Blood RISK6 scores were assessed using quantitative real-time PCR and evaluated by area under the receiver-operating characteristic curve (ROC AUC). RISK6 performance to discriminate ATB from HD reached an AUC of 0.94 (95% CI 0.89-0.99), with 90.9% sensitivity and 87.8% specificity, thus achieving the minimal WHO target product profile for a non-sputum-based TB screening test. Besides, RISK6 yielded an AUC of 0.93 (95% CI 0.85-1) with 90.9% sensitivity and 88.5% specificity for discriminating ATB from LTBI. Moreover, RISK6 showed higher performance (AUC 0.90, 95% CI 0.85-0.94) than IGRA-rmsHBHA (AUC 0.75, 95% CI 0.69-0.82) to differentiate TB infection stages. Finally, RISK6 signature scores significantly decreased after 2 months of TB treatment and continued to decrease gradually until the end of treatment reaching scores obtained in HD. We confirmed the performance of RISK6 signature as a triage TB test and its utility for treatment monitoring.

Objectives: The timely diagnosis of pulmonary tuberculosis (PTB) is challenging. Although pathogen-derived circulating cell-free DNA (cfDNA) has been detected in humans, the significance of Mycobacterium tuberculosis (MTB)-cfDNA detection in patients with PTB remains unclear., Methods: This study enrolled patients with PTB and persons with latent tuberculosis infection (LTBI) as the study and control groups, respectively, from 2018 to 2020. We measured interferon-γ levels and calculated blood monocyte-to-lymphocyte ratio (MLR). We conducted plasma cfDNA extraction, quantitative polymerase chain reaction (qPCR), and droplet digital PCR targeting the IS6110 gene of MTB. We calculated the sensitivity and specificity of using MTB-cfDNA to identify PTB and analyzed the factors associated with PTB diagnosis and MTB-cfDNA positivity., Results: We enrolled 24 patients with PTB and 57 LTBI controls. The sensitivity of using MTB-cfDNA to identify PTB was 54.2%(13/24) in total and 46.2%(6/13) in smear-negative cases. Two LTBI controls (3.5%) tested positive for MTB-cfDNA, indicating a specificity of 96.5%(55/57). By using MTB-cfDNA positivity and an MLR ≥0.42 to identify PTB, sensitivity increased to 79.2%(19/24). Among patients with PTB, MTB-specific interferon-γ levels were higher in MTB-cfDNA positive participants than in those who tested negative (7.0 ±2.7 vs 2.7±3.0 IU/mL, p<0.001). MTB-cfDNA levels declined after 2 months of anti-tuberculosis therapy (p<0.001)., Conclusion: The sensitivity of using MTB-cfDNA to identify PTB in participants was 54.2%, which increased to 79.2% after incorporating an MLR ≥0.42 into the analysis. MTB-cfDNA positivity was associated with MTB-specific immune response, and MTB-cfDNA levels declined after treatment. The clinical value of MTB-cfDNA in PTB management necessitates further investigation., Competing Interests: The authors have declared that no competing interests exist.

Background: Neutrophils are important for host innate immune defense and mediate inflammatory responses. Pulmonary tuberculosis (PTB) is associated with increased neutrophil granular protein (NGP) levels in the circulation. However, the systemic levels of neutrophil granular proteins were not examined in tuberculous lymphadenitis (TBL) disease., Methods: We measured the systemic levels of NGP (myeloperoxidase [MPO], elastase and proteinase 3 [PRTN3]) in TBL and compared them to latent tuberculosis (LTB) and healthy control (HC) individuals. We also measured the pre-treatment (Pre-T) and post-treatment (Post-T) systemic levels of neutrophil granular proteins in TBL individuals upon anti-tuberculosis treatment (ATT) completion. In addition, we studied the correlation and discriminatory ability of NGPs using receiver operating characteristic (ROC) analysis., Results: Our data suggests that systemic levels of NGPs (MPO, PRTN3, elastase) were significantly reduced in TBL individuals compared to LTB and HC individuals. Similarly, after ATT, the plasma levels of MPO and elastase but not PRTN3 were significantly elevated compared to pre-treatment levels. NGPs (except PRTN3) were positively correlated with absolute neutrophil count of TBL, LTB and HC individuals. Further, NGPs were able to significantly discriminate TBL from LTB and HC individuals., Conclusion: Hence, we conclude reduced neutrophil granular protein levels might be associated with disease pathogenesis in TBL., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Protective host responses in those exposed to or infected with tuberculosis (TB) is thought to require a delicate balance between pro-inflammatory and regulatory immune responses. Myeloid-derived suppressor cells (MDSCs), regulatory cells that dampen T-cell function, have been described in cancer and other infectious diseases but there are limited data on their role in TB., Methods: Peripheral blood was obtained from patients with active pulmonary TB and participants with presumed latent TB infection (LTBI) from Cape Town, South Africa. MDSC frequency was ascertained by flow cytometry. Purified MDSCs were used to assess (i) their suppressive effect on T-cell proliferation using a Ki67 flow cytometric assay and (ii) their effect on mycobacterial containment by co-culturing with H37 Rv -infected monocyte-derived macrophages and autologous pre-primed effector T-cells with or without MDSCs. Mycobacterial containment was measured by plating colony forming units (CFU)., Results: MDSCs (CD15 + HLA-DR - CD33 + ) had significantly higher median frequencies (IQR) in patients with active TB (n=10) versus LTBI (n= 10) [8.2% (6.8-10.7) versus 42.2% (27-56) respectively; p=0.001]. Compared to MDSC-depleted peripheral blood mononuclear and effector T cell populations, dilutions of purified MDSCs isolated from active TB patients suppressed T-cell proliferation by up to 72% (n=6; p=0.03) and significantly subverted effector T-cell-mediated containment of H37 Rv in monocyte-derived macrophages (n=7; 0.6% versus 8.5%; p=0.02)., Conclusion: Collectively, these data suggest that circulating MDSCs are induced during active TB disease and can functionally suppress T-cell proliferation and subvert mycobacterial containment. These data may inform the design of vaccines and immunotherapeutic interventions against TB but further studies are required to understand the mechanisms underpinning the effects of MDSCs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Davids, Pooran, Smith, Tomasicchio and Dheda.)

Background: Identifying and treating individuals with high risk of progression from latent tuberculosis infection to active tuberculosis (TB) disease is critical for eliminating the disease. We aimed to conduct a systematic review and meta-regression analysis to quantify the dose-response relationship between interferon-gamma release assay (IGRA) levels and the risk of progression to active TB., Methods: We searched PubMed and Embase from 1 January 2001 to 10 May 2020 for longitudinal studies that reported the risk of progression from latent to active TB as a function of baseline IGRA values. We used a novel Bayesian meta-regression method to pool effect sizes from included studies and generate a continuous dose-response risk curve. Our modeling framework enabled us to incorporate random effects across studies, and include data with different IGRA ranges across studies. The quality of included studies were assessed using the Newcastle-Ottawa scale (NOS)., Results: We included 34 studies representing 581,956 person-years of follow-up with a total of 788 incident cases of TB in the meta-regression analysis. Higher levels of interferon-gamma were associated with increased risk of progression to active tuberculosis. In the dose-response curve, the risk increased sharply between interferon-gamma levels 0 and 5 IU/ml, after which the risk continued to increase moderately but at a slower pace until reaching about 15 IU/ml where the risk levels off. Compared to 0 IU/ml, the relative risk of progression to active TB among those with interferon-gamma levels of 0.35, 1, 5, 10, 15, and 20 IU/ml were: 1.64 (1.28-2.08), 2.90 (2.02-3.88), 11.38 (6.64-16.38), 19.00 (13.08-26.90), 21.82 (14.65-32.57), and 22.31 (15.43-33.00), respectively. The dose-response relationship remains consistent when limiting the analysis to studies that scored highest in the NOS., Conclusion: The current practice of dichotomizing IGRA test results simplifies the TB infection disease continuum. Evaluating IGRA test results over a continuous scale could enable the identification of individuals at greatest risk of progression to active TB.

The mechanisms underlying the immunopathology of tuberculous meningitis (TBM), the most severe clinical form of extrapulmonary tuberculosis (TB), are not understood. It is currently believed that the spread of Mycobacterium tuberculosis (Mtb) from the lung is an early event that occurs before the establishment of adaptive immunity. Hence, several innate immune mechanisms may participate in the containment of Mtb infection and prevent extrapulmonary disease manifestations. Natural killer (NK) cells participate in defensive processes that distinguish latent TB infection (LTBI) from active pulmonary TB (PTB). However, their role in TBM is unknown. Here, we performed a cross-sectional analysis of circulating NK cellCID="C008" value="s" phenotype in a prospective cohort of TBM patients ( n = 10) using flow cytometry. Also, we addressed the responses of memory-like NK cell subpopulations to the contact with Mtb antigens in vitro . Finally, we determined plasma levels of soluble NKG2D receptor ligands in our cohort of TBM patients by enzyme-linked immunosorbent assay (ELISA). Our comparative groups consisted of individuals with LTBI ( n = 11) and PTB ( n = 27) patients. We found that NK cells from TBM patients showed lower absolute frequencies, higher CD69 expression, and poor expansion of the CD45RO + memory-like subpopulation upon Mtb exposure in vitro compared to LTBI individuals. In addition, a reduction in the frequency of CD56 bright CD16 - NK cells characterized TBM patients but not LTBI or PTB subjects. Our study expands on earlier reports about the role of NK cells in TBM showing a reduced frequency of cytokine-producing cells compared to LTBI and PTB., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 José Alberto Choreño-Parra et al.)

Immunocompromised status can result in indeterminate QuantiFERON-TB Gold In-Tube (QFT-GIT) results, but the association of indeterminate results with immunocompetent status in children is unknown. Therefore, we aimed to identify factors associated with indeterminate QFT-GIT results for immunocompetent children. We conducted a retrospective chart review of children (aged ≤ 18 years) who underwent QFT-GIT between September 2006 and July 2017 at the Severance Hospital, Seoul, South Korea. Of the 2037 QFT-GIT assays included in the present study, 7.7% yielded indeterminate QFT-GIT results. Multivariable logistic regression analysis identified younger age (OR 0.88; 95% CI 0.836-0.927; P < 0.001), elevated white blood cell (WBC) count (OR 1.066; 95% CI 1.020-1.115; P = 0.005), decreased albumin levels (OR 0.505; 95% CI 0.316-0.807; P = 0.004), and low-dose steroid therapy (< 1 mg/kg per day of prednisone or equivalent for < 2 weeks) (OR 76.146; 95% CI 8.940-648.569; P < 0.001) as significant factors influencing indeterminate results. Younger age, high WBC count, low albumin levels, and low-dose steroid therapy were associated with indeterminate QFT-GIT results. Low-dose steroid therapy had the highest OR for the indeterminate results compared to other significant risk factors. Our study suggests that screening for steroid doses is important prior to performing interferon-gamma release assays for immunocompetent children.

Background: Alterations in β common (βC) and γ common (γC) chain cytokines have been described in pulmonary tuberculosis. However, their role in tuberculous lymphadenitis (TBL) disease has not been assessed., Methods: Thus, in the present study, we have examined the systemic levels of βC and γC chain cytokines in TBL, latent tuberculosis (LTB) and healthy control (HC) individuals. We have examined the discriminatory potential of both family of cytokines using ROC analysis. Finally, we measured the pre and post-treatment responses of these cytokines after anti-tuberculosis treatment., Results: TBL individuals exhibit significantly increased (IL-3) and diminished systemic levels of (IL-5, GM-CSF) βC cytokines compared to LTB and HC individuals. TBL individuals also exhibit significantly diminished (IL-2, IL-7) and elevated (IL-4, IL-9) levels of γC cytokines compared to LTB and/or HC. ROC analysis shows a clear discriminatory capacity of both βC (IL-5) and γC (IL-2) chain cytokines to distinguish TBL from LTB and HCs. The systemic levels of βC chain cytokines were not significantly altered, but in contrast γC (IL-2 and IL-7) cytokines were significantly modulated after treatment. Finally, no significant correlation was observed for βC and γC chain cytokines with their respective lymphocyte count of TBL individuals., Conclusions: Hence, we conclude that altered plasma levels of βC and γC cytokines are the characteristics of immune alteration in TBL disease and certain cytokines were modulated after treatment., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Recent studies in adults have characterized differences in systemic inflammation between adults with and without latent tuberculosis infection (LTBI+ vs . LTBI-). Potential differences in systemic inflammation by LTBI status has not been assess in pregnant women., Methods: We conducted a cohort study of 155 LTBI+ and 65 LTBI- pregnant women, stratified by HIV status, attending an antenatal clinic in Pune, India. LTBI status was assessed by interferon gamma release assay. Plasma was used to measure systemic inflammation markers using immunoassays: IFN β , CRP, AGP, I-FABP, IFN γ , IL-1 β , soluble CD14 (sCD14), sCD163, TNF, IL-6, IL-17a and IL-13. Linear regression models were fit to test the association of LTBI status with each inflammation marker. We also conducted an exploratory analysis using logistic regression to test the association of inflammatory markers with TB progression., Results: Study population was a median age of 23 (Interquartile range: 21-27), 28% undernourished (mid-upper arm circumference (MUAC) <23 cm), 12% were vegetarian, 10% with gestational diabetes and 32% with HIV. In multivariable models, LTBI+ women had significantly lower levels of third trimester AGP, IL1β, sCD163, IL-6 and IL-17a. Interestingly, in exploratory analysis, LTBI+ TB progressors had significantly higher levels of IL1 β , IL-6 and IL-13 in multivariable models compared to LTBI+ non-progressors., Conclusions: Our data shows a distinct systemic immune profile in LTBI+ pregnant women compared to LTBI- women. Data from our exploratory analysis suggest that LTBI+ TB progressors do not have this immune profile, suggesting negative association of this profile with TB progression. If other studies confirm these differences by LTBI status and show a causal relationship with TB progression, this immune profile could identify subsets of LTBI+ pregnant women at high risk for TB progression and who can be targeted for preventative therapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer GW declared a past co-authorship with one of the authors BA to the handling editor., (Copyright © 2021 Naik, Alexander, Kumar, Kulkarni, Deshpande, Yadana, Leu, Araújo-Pereira, Andrade, Bhosale, Babu, Gupta, Mathad and Shivakoti.)

Anti-inflammatory cytokines act as double edged swords- they can dampen inflammation but can also suppress immunity. The role played by these cytokines in latent TB infected (LTBI) subjects, with various grades of glucose intolerance was studied. Both serum levels and recall-secretion of IL-27, IL-10, IL-1Ra and TGF-β in Normal Glucose Tolerance (NGT), Pre-Diabetes (PDM), Newly diagnosed Diabetes (NDM) and Known Diabetes (KDM) subjects, both with and without LTBI (n = 382), were quantified by ELISA. All the subjects were screened for LTBI by QuantiFERON-TB Gold test. Serum levels of IL-27, IL-10 and IL-1Ra were significantly elevated in the LTB - PDM, compared to LTB - NGT group. Increased IL-27 and IL-10 levels and decreased levels of TGF-β were seen in the LTB - NDM, compared to LTB - NGT group. Decreased serum levels of IL-27 and increased levels of IL-1Ra and TGF-β were seen in the LTB - KDM, compared to LTB - NGT group. TB antigens induced the secretion of IL-1Ra in LTB + subjects in the NGT, PDM and NDM groups, but not in the KDM group. Co-morbidity with LTBI brought about (diabetic) stage-specific modulation, in these cytokine levels. Major defects in the circulating levels and recall secretion of anti-inflammatory cytokines, as seen in LTB + KDM subjects, could fuel DM-TB synergy., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Current diagnostic tests for tuberculosis (TB) are not able to predict reactivation disease progression from latent TB infection (LTBI). The main barrier to predicting reactivation disease is the lack of our understanding of host biomarkers associated with progression from latent infection to active disease. Here, we applied an immune-based gene expression profile by NanoString platform to identify whole blood markers that can distinguish active TB from other lung diseases (OPD), and that could be further evaluated as a reactivation TB predictor. Among 23 candidate genes that differentiated patients with active TB from those with OPD, nine genes (CD274, CEACAM1, CR1, FCGR1A/B, IFITM1, IRAK3, LILRA6, MAPK14, PDCD1LG2) demonstrated sensitivity and specificity of 100%. Seven genes (C1QB, C2, CCR2, CCRL2, LILRB4, MAPK14, MSR1) distinguished TB from LTBI with sensitivity and specificity between 82 and 100%. This study identified single gene candidates that distinguished TB from OPD and LTBI with high sensitivity and specificity (both > 82%), which may be further evaluated as diagnostic for disease and as predictive markers for reactivation TB.

Although 23% of world population is infected with Mycobacterium tuberculosis ( M. tb ), only 5-10% manifest the disease. Individuals surely exposed to M. tb that remain asymptomatic are considered potential latent TB (LTB) cases. Such asymptomatic M. tb .-exposed individuals represent a reservoir for active TB cases. Although accurate discrimination and early treatment of patients with active TB and asymptomatic M. tb .-exposed individuals are necessary to control TB, identifying those individuals at risk of developing active TB still remains a tremendous clinical challenge. This study aimed to characterize the differences in the serum metabolic profile specifically associated to active TB infected individuals or to asymptomatic M. tb .-exposed population. Interestingly, significant changes in a specific set of metabolites were shared when comparing either asymptomatic house-hold contacts of active TB patients (HHC-TB) or active TB patients (A-TB) to clinically healthy controls (HC). Furthermore, this analysis revealed statistically significant lower serum levels of aminoacids such as alanine, lysine, glutamate and glutamine, and citrate and choline in patients with A-TB, when compared to HHC-TB. The predictive ability of these metabolic changes was also evaluated. Although further validation in independent cohorts and comparison with other pulmonary infectious diseases will be necessary to assess the clinical potential, this analysis enabled the discrimination between HHC-TB and A-TB patients with an AUC value of 0.904 (confidence interval 0.81-1.00, p -value < 0.0001). Overall, the strategy described in this work could provide a sensitive, specific, and minimally invasive method that could eventually be translated into a clinical tool for TB control.

Objectives: This study aims to explore the role of M2a polarization and formyl peptide receptor (FPR) regulation in the reactivation of Mycobacterium tuberculosis (Mtb) infection., Methods: M1/M2a monocyte percentage and FPR1/2/3 protein expression of blood immune cells were measured in 38 patients with sputum culture (+) active pulmonary TB disease, 18 subjects with latent TB infection (LTBI), and 28 noninfected healthy subjects (NIHS) using flow cytometry method., Results: M1 percentage was decreased in active TB versus either NIHS or LTBI group, while M2a percentage and M2a/M1 percentage ratio were increased. FPR1 expression on M1/M2a, FPR2 expression on M1, and FPR3 expression of M1 were all decreased in active TB versus LTBI group, while FPR1 over FPR2 expression ratio on NK T cell was increased in active TB versus either NIHS or LTBI group. In 11 patients with active TB disease, M1 percentage became normal again after anti-TB treatment. In vitro Mtb-specific antigen stimulation of monocytic THP-1 cells resulted in M2a polarization in association with increased FPR2 expression on M2a., Conclusions: Increased M2a and decreased M1 phenotypes of blood monocyte may serve as a marker for active TB disease, while decreased FPR1 on blood monocyte may indicate LTBI status., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Data from China have shown that the ratio of Mycobacterium tuberculosis-specific antigen (TBAg) spots obtained from the T-SPOT.TB test to the number of positive control phytohemagglutinin (PHA) spots (TBAg/PHA ratio) could help distinguish between active tuberculosis infection (ATBI) and latent tuberculosis infection (LTBI). As the applicability of the T-SPOT.TB test may differ according to region and race, we retrospectively verified the utility of the TBAg/PHA ratio in distinguishing between ATBI and LTBI in Japan. The TBAg/PHA ratio was significantly lower in the LTBI group than in the ATBI group. Area under the receiver operating characteristic curve (AUC) analysis between ATBI and LTBI according to the TBAg/PHA ratio was 0.76, with a sensitivity of 65.8% and a specificity of 75.6%. The best AUC was obtained when the TBAg/PHA ratio was divided by both lymphocyte count and albumin levels. Our results demonstrate that, in Japan, the TBAg/PHA ratio is superior to TBAg alone for distinguishing between ATBI and LTBI. In addition, the sensitivity and specificity were improved by combining the TBAg/PHA ratio with lymphocyte count and albumin levels., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Introduction: The World Health Organization has identified the need for a non-sputum-based test capable of detecting active tuberculosis (TB) as a priority. The plasma kynurenine-to-tryptophan (K/T) ratio, largely mediated by activity of the enzyme indoleamine 2,3-dioxygenase, may have potential as a suitable biomarker for active TB., Method: We evaluated a commercial enzyme-linked immunosorbent assay (ELISA) in comparison to mass spectrometry for measuring the K/T ratio. We also used ELISA to determine the K/T ratio in plasma from patients with active TB compared to latently infected controls, with and without HIV., Results: The two methods showed good agreement, with a mean bias of 0.01 (limit of agreement from -0.06 to 0.10). Using ELISA, it was found that HIV-infected patients with active TB disease had higher K/T ratios than those without TB (median, 0.101 [interquartile range (IQR), 0.091-0.140] versus 0.061 [IQR, 0.034-0.077], P<0.0001). At a cutoff of 0.080, the K/T ratio produced a sensitivity of 90%, a specificity of 80%, a positive predictive value (PPV) of 82%, and a negative predictive value (NPV) of 90%. In a receiver operating characteristics analysis, the K/T ratio had an area under the curve of 0.93. HIV-uninfected patients with active TB also had higher K/T ratios than those with latent TB infections (median, 0.064 [IQR, 0.040-0.088] versus 0.022 [IQR, 0.016-0.027], P<0.0001). A cutoff of 0.040 gave a sensitivity of 85%, a specificity of 92%, a PPV of 91%, and an NPV of 84%., Conclusion: The plasma K/T ratio is a sensitive biomarker for active TB. The K/T ratio can be measured from blood using ELISA. The K/T ratio should be evaluated as an initial test for TB., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: One forth whole-world population is infected with Mycobacterium tuberculosis (Mtb), but 90% of them are asymptotic latent infection without any symptoms but positive result in IFN-γ release assay. There is lack of ideal strategy to distinguish active tuberculosis (TB) and latent tuberculosis infection (LTBI). Some scientist had focused on a set of cytokines as biomarkers besides interferon- gamma (IFN-γ) to distinguish active TB and LTBI, but with considerable variance of results. This meta-analysis aimed to evaluate the overall discriminative ability of potential immune molecules to distinguish active TB and LTBI., Methods: PubMed, the Cochrane Library, and Web of Science databases were searched to identify studies assessing diagnostic roles of cytokines for distinguishing active TB and LTBI published up to August 2018. The quality of enrolled studies was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). The pooled diagnostic sensitivity and specificity of each cytokine was calculated by using Meta-DiSc software. Area under the summary receiver operating characteristic curve (AUC) was used to summarize the overall diagnostic performance of each biomarker., Results: Fourteen studies with 982 subjects met the inclusion criteria, including 526 active TB and 456 LTBI patients. Pooled sensitivity, specificity and AUC for discriminating between active TB and LTBI were analyzed for IL-2 (0.87, 0.61 and 0.9093), IP-10 (0.77, 0.73 and 0.8609), IL-5 (0.64, 0.75 and 0.8533), IL-13 (0.75, 0.71 and 0.8491), IFN-γ (0.67, 0.75 and 0.8031), IL-10 (0.68, 0.74 and 0.7957) and TNF-α (0.67, 0.64 and 0.7783). The heterogeneous subgroup analysis showed that cytokine detection assays, TB incidence, and stimulator with Mtb antigens are main influence factors for their diagnostic performance., Conclusions: The meta-analysis showed cytokine production could assist the distinction between active TB and LTBI, IL-2 with the highest overall accuracy. No single biomarker is likely to show sufficiently diagnostic performance due to limited sensitivity and specificity. Further prospective studies are needed to identify the optimal combination of biomarkers to enhanced diagnostic capacity in clinical practice.

Borderline interferon-gamma (IFN-γ) results (near the cut-off level 0.35 IU/ml) occur in QuantiFERON (QFT) assays. We investigated the performance of alternative biomarkers for classification of latent tuberculosis infection (LTBI) status in pregnant women with borderline QFT IFN-γ responses. Pregnant women (n = 96) were identified from a cohort study in Ethiopia, based on QFT-Plus IFN-γ results (QFT-low: <0.20 IU/ml, n = 33; QFT-borderline: 0.20-0.70 IU/ml, n = 31; QFT-high: >0.70 IU/ml, n = 32), including 12 HIV-positive individuals in each group and with 20 HIV-negative non-pregnant women from the same cohort with QFT IFN-γ <0.20 IU/ml as controls. Concentrations of 8 markers (IL-1ra, IL-6, IL-8, IP-10, MCP-1, MCP-2, osteopontin and resistin) were measured in whole blood QFT supernatants, stimulated separately with TB1 and TB2 antigens. K-nearest neighbor analysis (KNN) was used to classify participants with regard to likelihood of LTBI. Concentrations of MCP-2, IP-10 and IL-1ra were higher in QFT-borderline compared to QFT-low participants in both antigen stimulations (p < 0.001). KNN classification indicated high likelihood of LTBI in 13/31 (42%) women with QFT-borderline IFN-γ results. MCP-2, IP-10 and IL-1ra expressed in whole blood after TB antigen stimulation may be considered as alternative biomarkers for classification of LTBI status in pregnant women with borderline QFT IFN-γ results., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Discriminating active tuberculosis (ATB) from latent tuberculosis infection (LTBI) remains challenging. This study aimed to investigate a diagnostic model based on a combination of iron metabolism and the TB-specific antigen/phytohemagglutinin ratio (TBAg/PHA ratio) in T-SPOT.TB assay for differentiation between ATB and LTBI., Methods: A total of 345 participants with ATB (n=191) and LTBI (n=154) were recruited based on positive T-SPOT.TB results at Tongji hospital between January 2017 and January 2020. Iron metabolism analysis was performed simultaneously. A diagnostic model for distinguishing ATB from LTBI was established according to multivariate logistic regression., Results: The TBAg/PHA ratio showed 64.00% sensitivity and 90.10% specificity in distinguishing ATB from LTBI when a threshold of 0.22 was used. All iron metabolism biomarkers in the ATB group were significantly different from those in the LTBI group. Specifically, serum ferritin and soluble transferrin receptor in ATB were significantly higher than LTBI. On the contrary, serum iron, transferrin, total iron binding capacity, and unsaturated iron binding capacity in ATB were significantly lower than LTBI. The combination of iron metabolism indicators accurately predicted 60.00% of ATB cases and 91.09% of LTBI subjects, respectively. Moreover, the combination of iron metabolism indexes and TBAg/PHA ratio resulted in a sensitivity of 88.80% and specificity of 90.10%. Furthermore, the performance of models established in the Qiaokou cohort was confirmed in the Caidian cohort., Conclusions: The data suggest that the combination of iron metabolism indexes and TBAg/PHA ratio could serve as a biomarker to distinguish ATB from LTBI in T-SPOT-positive individuals., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

In our work, we aim to identify new candidate host biomarkers to discriminate between active TB patients (n = 28), latent infection (LTBI; n = 27) and uninfected (NoTBI; n = 42) individuals. For that, active TB patients and their contacts were recruited that donated serum and saliva samples. A multiplex assay was performed to study the concentration of different cytokines, chemokines and growth factors. Proteins with significant differences between groups were selected and logistic regression and the area under the ROC curve (AUC) was used to assess the diagnostic accuracy. The best marker combinations that discriminate active TB from NoTBI contacts were [IP-10 + IL-7] in serum and [Fractalkine + IP-10 + IL-1α + VEGF] in saliva. Best discrimination between active TB and LTBI was achieved using [IP-10 + BCA-1] in serum (AUC = 0.83) and IP-10 in saliva (p = 0.0007; AUC = 0.78). The levels of TNFα (p = 0.003; AUC = 0.73) in serum and the combination of [Fractalkine+IL-12p40] (AUC = 0.83) in saliva, were able to differentiate between NoTBI and LTBI contacts. In conclusion, different individual and combined protein markers could help to discriminate between active TB and both uninfected and latently-infected contacts. The most promising ones include [IP-10 + IL-7], [IP-10 + BCA-1] and TNFα in serum and [Fractalkine + IP-10 + IL-1α + VEGF], IP-10 and [Fractalkine+IL-12p40] in saliva., Competing Interests: A González-Fernández is co-promotor of the company NanoImmunoTech. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Background: Dynamically changed levels of serum cytokines might predict the development of active TB from latent tuberculosis infection (LTBI) and monitor preventive treatment effectiveness. The aim of the study was to identify potential serum cytokines associated with LTBI treatment which might predict active disease development in a Chinese population., Methods: Based on a randomized controlled trial aiming to explore short-course regimens for LTBI treatment, the dynamic changes of serum cytokines determined by bead-based multiplex assays were investigated for the participants who developed active TB during follow-up and age and gender matched controls stayed healthy., Results: Totally, 21 patients diagnosed with active tuberculosis (TB) during the 2-year follow-up (12 from treated groups and 9 from untreated controls) and 42 age and gender matched healthy controls (24 from treated groups and 18 from untreated controls) were included in the study. Before treatment, serum IL-1ra was statistically higher among those who developed active disease during follow-up as compared with those stayed healthy. As for treated participants, the levels of IL-1ra were significantly lower after treatment in comparison with those before treatment both in active TB group (p = 0.002) and non-TB group (p = 0.009). For untreated participants, the levels of IL-1ra were not statistically different between different time points both in active TB group (p = 0.078) and non-TB group (p = 0.265)., Conclusion: Our results suggested that declined serum level of IL-1ra was associated with LTBI treatment. Further studies are needed to verify whether it could be used to evaluate LTBI treatment and to predict active disease development.

Tuberculin skin test (TST) and IFN-γ release assays are currently used to detect Mycobacterium tuberculosis (Mtb) infection but none of them differentiate active from latent infection (LTBI). Since improved tests to diagnose Mtb infection are required, we studied the immune response to Mtb latency antigen Rv2626c in individuals exposed to the bacteria during different periods. Tuberculosis patients (TB), TB close contacts (CC: subjects exposed to Mtb for less than three months) and healthcare workers (HW: individuals exposed to Mtb at least two years) were recruited and QuantiFERON (QFT) assay, TST and IFN-γ secretion to Rv2626c were analyzed. Twenty-two percent of the individuals assessed had discordant results between QFT and TST tests. Furthermore, QFT negative and QFT positive individuals produced differential levels of IFN-γ against Rv2626c, in direct association with their exposure period to Mtb. Actually, 91% of CC QFT negative subjects secreted low levels of IFN-γ to Rv2626c, whereas 43% of HW QFT negative people produced elevated IFN-γ amounts against Rv2626c. Conversely, 69% of CC QFT positive subjects didn´t produce IFN-γ to Rv2626c. Interestingly, a similar pattern of IgG anti-Rv2626c plasma levels was observed. Therefore, determination of IFN-γ and IgG levels against the dormancy antigen Rv2626c allows to identify established LTBI.

Pulmonary tuberculosis is associated with higher plasma levels of antimicrobial peptides (AMPs) and lower granulysin levels. However, the association of AMPs with tuberculous lymphadenitis (TBL) is not well studied. Hence, we measured the plasma levels of human beta defensin-2 (HBD2), granulysin, human neutrophil peptides 1-3 (HNP1-3) and cathelicidin (LL37) in TBL compared to latent tuberculosis (LTB) and healthy controls (HC) and in TBL individuals upon completion of anti-tuberculosis treatment (ATT). We examined the association of AMPs with TBL lymph node culture grade or lymph node involvement. Finally, the discriminatory potential of these proteins was assessed using receiver operating characteristic (ROC) analysis. TBL individuals display significantly diminished circulating levels of AMPs (granulysin and HNP1-3) but not HBD-2 and LL-37 in comparison to LTB and HCs. Similarly, after ATT, both HBD-2 and HNP1-3 were significantly elevated and LL-37 was significantly reduced in TBL individuals. Granulysin and HNP1-3 discriminates TBL from LTB and HC individuals upon ROC analysis. AMPs did not exhibit significant correlation either with lymph node culture grades or lymph node involvement. Overall, TBL individuals show decreased AMPs and their reversal after ATT suggesting their association with underlying immune alteration in this poorly studied form of TB disease., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objective: To explore the non-target metabonomics of serum in worker's pneumoconiosis (CWP) patients with latent tuberculosis and the biomarkers of latent tuberculosis infection of pneumoconiosis. Methods: In December 2018, 39 CWP inpatients from a hospital in Beijing were taken as subjects. The subjects were screened for latent tuberculosis using the in vitro release test of mycobacterium tuberculosis-interferon (IGRAs) test. According to the screening results, 21 positive patients with latent tuberculosis infection were selected as the latent tuberculosis group of pneumoconiosis. While 18 negative patients with CWP alone were selected as the pneumoconiosis group. Polarity components of metabolites were analyzed by UPLC-QTOF/MS. The data was processed with Progenesis QI software for multidimensional statistical analysis. Identification of structure of differential metabolites were matched through accurate mass and secondary mass spectrum. Searching the Human Metabolome Database (HMDB) , differential metabolites were imported into MetaboAnalyst 4.0 to analyze the metabolic pathways. Results: All 42 differential metabolites were screened out. Excepted for exogenous metabolites, 14 endogenous differential metabolites were identified. Compared with the pneumoconiosis group, 6 metabolites including PC [18∶4 (6Z, 9Z, 12Z, 15Z) /P-18∶1 (11Z) ], 3-Oxododecanoyl-CoA in the latent tuberculosis group were up-regulated, while 8 metabolites including the Stearoyl-CoA, (2S) -Pristanoyl-CoA were down-regulated. These results might be related to lipid, fatty acid and arachidonic acid metabolism pathways. Conclusion: There are significant differences in serum metabonomics between the patients with latent tuberculosis of pneumoconiosis and the patients with ordinary pneumoconiosis, which provide a reference for the study of biomarkers for the diagnosis of latent tuberculosis infection of pneumoconiosis.

Markers for monitoring clearance of Mycobacterium tuberculosis (Mtb) infection during anti-TB drug treatment could facilitate management of tuberculosis (TB) treatment, but are lacking. We aimed to screen for Mtb clearance markers from in-vitro-infected leucocytes and to evaluate these markers in followed-up active TB (ATB) patients and latent TB (LTBI) cases after anti-TB drug treatment. Extracellular proteins from primary leucocytes infected with each of the Mtb lineages (East-Asian, Indo-Oceanic, Euro-American and the laboratory strain H37Rv) were screened as possible clearance markers. Leucocytes infected with Staphylococcus aureus acted as controls. The proteomic analysis was performed using GeLC-MS/MS. Several quantitative and qualitative candidate clearance markers were found. These proteins were suppressed during the infection stage of all Mtb lineages and re-expressed after bacillary clearance. PSTK, FKBP8 and MGMT were common clearance markers among the four Mtb lineages in our model. Only PSTK was a potential clearance marker based on western blot validation analysis from culture supernatants. The PSTK marker was further validated with western blot analysis using serum samples (n = 6) from ATB patients and LTBI cases during anti-TB drug treatment, and from healthy controls (n = 3). Time-dependent increase of PSTK was found both in ATB and LTBI patients during the course of anti-TB drug treatment, but not in healthy controls. We have demonstrated that PSTK is a potential treatment-monitoring marker for active and latent TB., Competing Interests: The authors declare there are no competing interests.

Background: To facilitate better discrimination between patients with active tuberculosis (TB) and latent TB infection (LTBI), whole blood transcriptomic studies have been performed to identify novel candidate host biomarkers. SERPING1, which encodes C1-inhibitor (C1-INH), the natural inhibitor of the C1-complex has emerged as candidate biomarker. Here we collated and analysed SERPING1 expression data and subsequently determined C1-INH protein levels in four cohorts of patients with TB., Methods: SERPING1 expression data were extracted from online deposited datasets. C1-INH protein levels were determined by ELISA in sera from individuals with active TB, LTBI as well as other disease controls in geographically diverse cohorts., Findings: SERPING1 expression was increased in patients with active TB compared to healthy controls (8/11 cohorts), LTBI (13/14 cohorts) and patients with other (non-TB) lung-diseases (7/7 cohorts). Serum levels of C1-INH were significantly increased in The Gambia and Italy in patients with active TB relative to the endemic controls but not in South Africa or Korea. In the largest cohort (n = 50), with samples collected longitudinally, normalization of C1-INH levels following successful TB treatment was observed. This cohort, also showed the most abundant increase in C1-INH, and a positive correlation between C1q and C1-INH levels. Combined presence of increased levels of both C1q and C1-INH had high specificity for active TB (96 %) but only very modest sensitivity 38 % compared to the endemic controls., Interpretation: SERPING1 transcript expression is increased in TB patients, while serum protein levels of C1-INH were increased in half of the cohorts analysed., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Tuberculosis (TB) continues to be a critical global health problem, which killed millions of lives each year. Certain circulating cell subsets are thought to differentially modulate the host immune response towards Mycobacterium tuberculosis (Mtb) infection, but the nature and function of these subsets is unclear., Methods: Peripheral blood mononuclear cells (PBMC) were isolated from healthy controls (HC), latent tuberculosis infection (LTBI) and active tuberculosis (TB) and then subjected to single-cell RNA sequencing (scRNA-seq) using 10 × Genomics platform. Unsupervised clustering of the cells based on the gene expression profiles using the Seurat package and passed to tSNE for clustering visualization. Flow cytometry was used to validate the subsets identified by scRNA-Seq., Findings: Cluster analysis based on differential gene expression revealed both known and novel markers for all main PBMC cell types and delineated 29 cell subsets. By comparing the scRNA-seq datasets from HC, LTBI and TB, we found that infection changes the frequency of immune-cell subsets in TB. Specifically, we observed gradual depletion of a natural killer (NK) cell subset (CD3-CD7+GZMB+) from HC, to LTBI and TB. We further verified that the depletion of CD3-CD7+GZMB+ subset in TB and found an increase in this subset frequency after anti-TB treatment. Finally, we confirmed that changes in this subset frequency can distinguish patients with TB from LTBI and HC., Interpretation: We propose that the frequency of CD3-CD7+GZMB+ in peripheral blood could be used as a novel biomarker for distinguishing TB from LTBI and HC. FUND: The study was supported by Natural Science Foundation of China (81770013, 81525016, 81772145, 81871255 and 91942315), National Science and Technology Major Project (2017ZX10201301), Science and Technology Project of Shenzhen (JCYJ20170412101048337) and Guangdong Provincial Key Laboratory of Regional Immunity and Diseases (2019B030301009). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Pro-inflammatory cytokines are markers of disease severity and bacterial burden in pulmonary tuberculosis (PTB). However, the association of Type 2, regulatory and other anti-inflammatory cytokines with disease severity and bacterial burden in PTB is not well understood., Aims/methodology: To examine the association of anti-inflammatory cytokines with PTB, we examined the plasma levels of Type 2 (IL-4, IL-5, IL-13), regulatory (IL-10, TGFβ) and other anti-inflammatory (IL-19, IL-27, IL-37) cytokines in individuals with PTB, latent TB (LTB) or healthy controls (HC). We also examined the plasma levels of these cytokines in PTB individuals following anti-tuberculosis therapy (ATT)., Results: PTB individuals exhibited significantly higher plasma levels of IL-4, IL-13, IL-10, IL-19 and IL-27 in comparison to LTB and HC individuals and of TGFβ in comparison to HC individuals. In contrast, PTB individuals exhibited significantly lower plasma levels of IL-5 and IL-37 in comparison to both LTB and HC individuals. PTB individuals with bilateral or cavitary disease did not exhibit significantly different plasma levels of these cytokines in comparison to those with unilateral or non-cavitary disease nor did the cytokines exhibit any significant relationship with bacterial burdens. Finally, following ATT, the plasma levels of IL-4, IL-5 and IL-10 were significantly decreased, while the plasma levels of IL-13 and IL-37 were significantly increased in PTB individuals., Conclusion: Therefore, our data demonstrate that PTB is associated with altered levels of Type 2, regulatory and other anti-inflammatory cytokines, some of which are altered followed chemotherapy. Our data also reveal that anti-inflammatory cytokines are not markers of disease severity or bacterial burden in PTB. Elevations in anti-inflammatory cytokines might help prevent the detrimental effects of pro-inflammatory responses in PTB., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)