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Background: The Directly Observed Treatment-Short Course (DOTS) Programme was implemented by WHO and includes a combination of four anti-tuberculosis (TB) drugs (isoniazid, pyrazinamide, ethambutol and rifampicin) for a period of six months to eradicate the TB infection completely. Diabetes mellitus (DM) is recognized as one of a strong contributor of TB according to World Health Organization (WHO). The presence of diabetes mellitus type 2 (DM type 2) makes TB treatment complicated. Thus, the objective of the current meta-analysis was to identify and quantify the impact of type 2 DM on treatment outcomes of TB patients treated under the DOTS Programme., Methods: This meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Through a systematic review of relevant literature, we focused on studies investigating treatment outcomes including extended treatment duration and recurrence for individuals with both TB and DM undergoing DOTS therapy. The extracted information included study designs, sample sizes, patient characteristics and reported treatment results., Results: In 44 studies from different parts of the world, the pooled HR for the impact of DM on extended treatment duration and reoccurrence were HR 0.72, 95% CI 0.56-0.83, p  < .01 and HR 0.93, 95% CI 0.70-1.04, p  = .08, respectively. The pooled HR for impact of DM on composite TB treatment outcomes was calculated as 0.76 (95% CI 0.60-0.87), p  < .01 with an effect size of 41.18. The heterogeneity observed among the included studies was moderate ( I 2  = 55.79%)., Conclusions: A negative impact of DM was found on recurrence and extended treatment duration in TB patients treated with DOTS therapy. DM type 2 is responsible for the TB treatment prolongation and TB recurrence rates. By implementing effective management strategies and advancing research, the challenges can be mitigated, arising due to the complex interaction between DM and TB.

Background: Few studies have evaluated the association between preexisting vitamin D deficiency and incident tuberculosis (TB). We assessed the impact of baseline vitamins D levels on TB disease risk., Methods and Findings: We assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6,751 HIV-negative household contacts of TB patients enrolled between September 1, 2009, and August 29, 2012, in Lima, Peru. We screened for TB disease at 2, 6, and 12 months after enrollment. We defined cases as household contacts who developed TB disease at least 15 days after enrollment of the index patient. For each case, we randomly selected four controls from among contacts who did not develop TB disease, matching on gender and year of age. We also conducted a one-stage individual-participant data (IPD) meta-analysis searching PubMed and Embase to identify prospective studies of vitamin D and TB disease until June 8, 2019. We included studies that assessed vitamin D before TB diagnosis. In the primary analysis, we defined vitamin D deficiency as 25-(OH)D < 50 nmol/L, insufficiency as 50-75 nmol/L, and sufficiency as >75nmol/L. We estimated the association between baseline vitamin D status and incident TB using conditional logistic regression in the Lima cohort and generalized linear mixed models in the meta-analysis. We further defined severe vitamin D deficiency as 25-(OH)D < 25 nmol/L and performed stratified analyses by HIV status in the IPD meta-analysis. In the Lima cohort, we analyzed 180 cases and 709 matched controls. The adjusted odds ratio (aOR) for TB risk among participants with baseline vitamin D deficiency compared to sufficient vitamin D was 1.63 (95% CI 0.75-3.52; p = 0.22). We included seven published studies in the meta-analysis and analyzed 3,544 participants. In the pooled analysis, the aOR was 1.48 (95% CI 1.04-2.10; p = 0.03). The aOR for severe vitamin D deficiency was 2.05 (95% CI 0.87-4.87; p trend for decreasing 25-(OH)D levels from sufficient vitamin D to severe deficiency = 0.02). Among 1,576 HIV-positive patients, vitamin D deficiency conferred a 2-fold (aOR 2.18, 95% CI 1.22-3.90; p = 0.01) increased risk of TB, and the aOR for severe vitamin D deficiency compared to sufficient vitamin D was 4.28 (95% CI 0.85-21.45; p = 0.08). Our Lima cohort study is limited by the short duration of follow-up, and the IPD meta-analysis is limited by the number of possible confounding covariates available across all studies., Conclusion: Our findings suggest vitamin D predicts TB disease risk in a dose-dependent manner and that the risk of TB disease is highest among HIV-positive individuals with severe vitamin D deficiency. Randomized control trials are needed to evaluate the possible role of vitamin D supplementation on reducing TB disease risk., Competing Interests: The authors of this manuscript have the following competing interests: MBM is a member of the Editorial Board of PLOS Medicine. All other authors have declared no competing interests.

Introduction: Expression of Suppressor of cytokine signaling (SOCS)-1 molecules is increased in patients with tuberculosis (TB). Early Secreted Antigen Target (ESAT)-6 kDa - induced IFN-γ responses indicate Mycobacterium tuberculosis infection. The effect of ESAT6- stimulation on SOCS1 in the host is not known., Methodology: Healthy asymptomatic controls had a negative (n = 16) or a positive ( n = 13) tuberculin skin test (TST). ESAT6-induced IFN-γ responses classified these controls as positive (EC ESAT6 IFN-γ (+), n = 5) or negative (EC ESAT6 IFN-γ (-), n = 24) responders. Patients had pulmonary (n = 21) or extra-pulmonary (n = 30) tuberculosis. Peripheral blood cells were stimulated with ESAT6 and mRNA expression of IFN-γ and SOCS1 was determined., Results: ESAT6-induced IFN-γ expression was raised in EC ESAT6 IFN-γ (+) as compared with EC ESAT6 IFN-γ (-), p = 0.019. ESAT6-induced SOCS1 mRNA expression was increased in both pulmonary TB and extra-pulmonary TB patients as compared with both EC groups. ESAT6-induced IFN-γ/SOCS1 mRNA expression ratio was decreased in TB patients as compared with both EC groups., Conclusion: M. tuberculosis infection induces increased ESAT6-induced IFN-γ responses in both latent and active TB. Our data shows down-regulation of IFN-γ / SOCS1 expression to be induced only in active TB cases, distinguishing them from healthy individuals likely to have latent TB. A decreasing IFN-γ /SOCS1 ratio may leads to reduced Th1 immunity which contributes to inability of the host to control clinical disease.

Background: Appropriate immune activation of T cells and macrophages is central for the control of Mycobacterium tuberculosis infections. IFN-γ stimulated responses are lowered in tuberculosis (TB), while expression of Suppressor of Cytokine Signaling (SOCS) molecules - 1 and 3 and CD4+CD25+FoxP3+T regulatory cells is increased. Here we investigated the association of these molecules in regard to clinical severity of TB., Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from patients with pulmonary TB (PTB, n = 33), extra-pulmonary TB (ETB, n = 33) and healthy endemic controls (EC, n = 15). Cases were classified as moderately advanced or far advanced PTB, and less severe or severe disseminated ETB. M. tuberculosis -stimulated IFN-γ, SOCS1, SOCS3 and FoxP3 gene expression and secretion of Th1 and Th2 cytokines was measured. Statistical analysis was performed using Mann-Whitney U, Wilcoxon Rank and Kruskal Wallis non-parametric tests., Results: In un-stimulated PBMCs, IL-6 (p = 0.018) and IL-10 (p = 0.013) secretion levels were increased in PTB while IL-10 was also increased in ETB (p = 0.003), all in comparison with EC. M. tuberculosis-stimulated IL-6 (p = 0.003) was lowered in ETB as compared with EC. SOCS1 mRNA expression in M. tuberculosis stimulated PBMCs levels in moderately advanced PTB (p = 0.022), far advanced (p = 0.014) PTB, and severe ETB (p = 0.009) were raised as compared with EC. On the other hand, SOCS1 mRNA titers were reduced in less severe ETB, in comparison with severe ETB (p = 0.027) and far advanced PTB (p = 0.016). SOCS3 mRNA accumulation was reduced in far advanced PTB (p = 0.007) and FoxP3 mRNA expression was increased in less severe ETB as compared with EC (p = 0.017)., Conclusions: The lowered SOCS1 mRNA levels in patients with less severe extra-pulmonary TB as compared to those with more severe ETB and PTB may lead to elevated IFN-γ pathway gene expression in the latter group. As localized ETB has shown to be associated with more effective Th1 immunity and adaptive responses, this suggests a role for SOCS1 in determining disease outcome in extra-pulmonary TB.

Differential T cell trafficking through the blood compartment towards infected foci may be occurring in different stages of tuberculosis disease and infection. The aim of the present study was to identify cytokine signatures in the blood compartment in tuberculosis patients with pulmonary disease (PTB=19), recently exposed household contacts (HC=27) and nonexposed community controls (EC=37). Diluted (1:10) whole blood was cultured for 2 days and cytokine secretion was assessed using Cytometric Bead Array (Th1/Th2 kit II; BD Biosciences) which included IL-2, TNF-α, IFN-γ (Type1/T1), IL-4, IL-6 and IL-10 (Type2/T2). All T1/T2 cytokines were elevated in PTB (AUROC>0.9) while HC showed selective elevation of IL-6 (AUROC>0.7) compared to EC. Principal component analysis (PCA) extracted two groupings with Eigen values >1; IL-6 separated into the second component for PTB, HC and EC. After rotation, IFN-γ was correlated with the first component for PTB and EC and the second component for HC indicating an absence of T1/T2 dichotomy. Therefore endogenous cytokine signatures may indicate differential T cell trafficking in different stages of tuberculosis infection and disease., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Helicobacter pylori, a lifelong and typically asymptomatic infection of the stomach, profoundly alters gastric immune responses, and may benefit the host in protection against other pathogens. We explored the hypothesis that H. pylori contributes to the control of infection with Mycobacterium tuberculosis., Methodology/principal Findings: We first examined M. tuberculosis-specific IFN-gamma and H. pylori antibody responses in 339 healthy Northern Californians undergoing routine tuberculin skin testing. Of 97 subjects (29%) meeting criteria for latent tuberculosis (TB) infection (LTBI), 45 (46%) were H. pylori seropositive. Subjects with LTBI who were H. pylori-seropositive had 1.5-fold higher TB antigen-induced IFN-gamma responses (p = 0.04, ANOVA), and a more Th-1 like cytokine profile in peripheral blood mononuclear cells, compared to those who were H. pylori seronegative. To explore an association between H. pylori infection and clinical outcome of TB exposure, we evaluated H. pylori seroprevalence in baseline samples from two high risk TB case-contact cohorts, and from cynomolgus macaques experimentally challenged with M. tuberculosis. Compared to 513 household contacts who did not progress to active disease during a median 24 months follow-up, 120 prevalent TB cases were significantly less likely to be H. pylori infected (AOR: 0.55, 95% CI 0.0.36-0.83, p = 0.005), though seroprevalence was not significantly different from non-progressors in 37 incident TB cases (AOR: 1.35 [95% CI 0.63-2.9] p = 0.44). Cynomolgus macaques with natural H. pylori infection were significantly less likely to progress to TB 6 to 8 months after M. tuberculosis challenge (RR: 0.31 [95% CI 0.12-0.80], p = 0.04)., Conclusions/significance: H. pylori infection may induce bystander effects that modify the risk of active TB in humans and non-human primates. That immunity to TB may be enhanced by exposure to other microbial agents may have important implications for vaccine development and disease control.

The high prevalence of Mycobacterium tuberculosis makes it imperative that immune responses to evaluate could be predictive of infection. We investigated live Mycobacterium- and recombinant antigen-induced cytokine and chemokine responses in patients with active tuberculosis (TB) compared with those of healthy controls from an area where TB is endemic (ECs). M. tuberculosis-, M. bovis BCG-, ESAT6-, and culture filtrate protein 10 (CFP10)-induced responses were determined in peripheral blood mononuclear cells from patients with pulmonary TB (n = 38) and ECs (n = 39). The levels of the cytokines gamma interferon (IFN-gamma) and interleukin-10 (IL-10) and the chemokines CCL2, CCL3, and CXCL9 were measured. The levels of M. tuberculosis- and BCG-induced IFN-gamma secretion were significantly reduced (P = 0.002 and P < 0.01, respectively), while the amount of IL-10 induced by both virulent (P < 0.01) and avirulent (P = 0.002) mycobacteria was increased in patients with TB. The ESAT6-induced IFN-gamma responses were increased in the patients with TB (P = 0.013) compared with those in the EC group. When tuberculin skin test (TST)-negative (TST(-); induration, <10 mm) and TST-positive (TST(+)) donors were studied separately, both TST(-) and TST(+) individuals showed increased IFN-gamma responses to M. tuberculosis compared with the responses of the patients with TB (P = 0.037 and P = 0.006, respectively). However, only TST(+) ECs showed reduced IFN-gamma responses to ESAT6 (P = 0.008) compared with the responses of the patients with TB. The levels of M. tuberculosis-induced CCL2 (P = 0.006) and CXCL9 (P = 0.017) were greater in the patients with TB. The levels of CCL3 secretion in response to Mycobacterium and antigen stimulation were comparable between the two groups. While the levels of ESAT6-induced chemokines did not differ between the patients with TB and the ECs, the levels of CFP10-induced CCL2 (P = 0.01) and CXCL9 (P = 0.001) were increased in the patients. These data indicate differential host IFN-gamma, CXCL9, and CCL2 responses to live mycobacteria and mycobacterial antigens and have implications for the identification of potential biomarkers of infection which could be used for the diagnosis of TB.

Pakistan ranks eighth in terms of tuberculosis burden worldwide, with an incidence of 181/100000. The predominant genotypes of Mycobacterium tuberculosis are reported to be the Central Asian strain 1 (CAS1) and Beijing families.Mycobacteriumtuberculosis down-regulates host pro-inflammatory cytokines, which are essential for protection against infection. There is currently little information regarding the interaction of the CAS1 genotype with host cells. We studied the growth rates of CAS1 and Beijing clinical isolates, and their ability to induce cytokines compared with the laboratory reference strain H37Rv. Host responses were studied using a THP-1 monocytic cell line model and an ex vivo whole blood assay. Growth rates of CAS1 and Beijing isolates were significantly lower (P=0.011) compared with H37Rv. All clinical isolates induced significantly lower levels of TNF-alpha secretion (P=0.003) than H37Rv in THP-1 cells and in the whole blood assay of healthy donors (n=8). They also induced lower IFN-gamma secretion in the whole blood assay (P<0.001). A positive correlation was observed between the growth indices (GI) of H37Rv, Beijing and CAS1 strains and the TNF-alpha responses they induced [Pearson's correlation coefficient (R(2)): 0.936, 0.775 and 0.55, respectively], and also between GI and IFN-gamma production (R(2): 0.422, 0.946, 0.674). These findings suggest that reduced growth rate, together with down-modulation of pro-inflammatory cytokines, is a contributory mechanism for the predominance of the CAS genotype.

Background: Pakistan ranks 7(th) globally in terms of tuberculosis (TB) disease burden (incidence 181/100000 pop./yr; prevalence of 329/pop./yr). Reports from different populations show variable associations of TB susceptibility and severity with cytokine gene polymorphisms. Tuberculosis clinical severity is multi-factorial and cytokines play a pivotal role in the modulation of disease severity. We have recently reported that the ratio of two key cytokines (IFNgamma and IL10) show significant correlation with the severity spectrum of tuberculosis. The objective of the current study was to analyze the frequency of cytokine gene polymorphisms linked to high and low responder phenotypes (IFNgamma +874 T(hi)-->A(lo) and IL10 -1082 G(lo)-->A(hi)) in tuberculosis patients., Methods and Findings: STUDY GROUPS WERE STRATIFIED ACCORDING TO DISEASE SITE AS WELL AS DISEASE SEVERITY: Pulmonary N = 111 (Minimal, PMN = 19; Moderate, PMD = 63; Advance, PAD = 29); Extra-pulmonary N = 67 (Disseminated DTB = 20, Localized LTB = 47) and compared with healthy controls (TBNA = 188). Genotype analyses were carried out using amplification refractory mutation system-PCR (ARMS-PCR) and stimulated whole blood (WB) culture assay was used for assessing cytokine profiles. Our results suggest that the IFNgamma +874 TT genotype and T allele was overrepresented in PMN (p = 0.01) and PMD (p = 0.02). IFNgamma +874 TT in combination with IL10 GG(lo) genotypes showed the highest association (chi(2) = 6.66, OR = 6.06, 95% CI = 1.31-28.07, p = 0.01). IFNgamma AA(lo) on the other hand in combination with IL10 GG(lo) increased the risk of PAD (OR = 5.26; p = 0.005) and DTB (OR = 3.59; p = 0.045)., Conclusion: These findings are consistent with the role of IL10 in reducing collateral tissue damage and the protective role of IFNgamma in limiting disease in the lung.

Several cytokines (IFN gamma, TNF alpha, IL10 and IL6) show an association with either disease localization or dissemination in tuberculosis. There are also reports of involvement of extra-pulmonary sites in tuberculosis with differential clinical severity. However, no comparative study of biomarkers across the disease severity spectrum is available. This was the purpose of the current study. Cytokines (IFN gamma, TNFalpha, IL10 and IL6) secreted in response to a panel of stimulants (PHA, LPS or mycobacterial antigens) in whole blood were determined in eighty-two tuberculosis patients. WHO criteria was applied for stratification of patients according to disease severity: disseminated and or severe disease (EPTB1; N=29); disease localized to lung parenchyma (PTB; N=32) and disease localized to peripheral sites without lung involvement (EPTB2; N=21). Mycobacterial antigens induced IFN gamma/IL10 ratio showed a direct relationship with disease severity ranking (median ratios: EPTB1=0.21; PTB=0.85; EPTB2=7.7) and the highest correlation (Spearman Rank; rho=0.673, p<0.000001). IFN gamma/IL10 ratio also rank ordered clinical severity as it relates to anatomic sites. IFN gamma/IL10 ratio may therefore provide a useful objective marker of disease severity in both pulmonary and extra-pulmonary tuberculosis.

Background: Tuberculosis causes 3 million deaths annually. The most common site of tuberculosis is pulmonary however; extra-pulmonary forms of the disease also remain prevalent. Restriction of Mycobacterium tuberculosis depends on effective recruitment and subsequent activation of T lymphocytes, mononuclear and polymorphonuclear cells to the site of infection. Tumor necrosis factor (TNF)-alpha is essential for granuloma formation and is a potent activator of monocyte chemotactic protein (MCP-1, CCL2). CCL2 is essential for recruitment of monocytes and T cells and has been shown to play a role in protection against tuberculosis. Interleukin -8 (CXCL8) is a potent activator of neutrophils. Increased levels of CCL2, CXCL8 and TNFalpha are reported in tuberculosis but their significance in different forms of tuberculosis is as yet unclear. We have used an ex vivo assay to investigate differences in immune parameters in patients with either pulmonary or extra-pulmonary tuberculosis., Methods: Serum levels of CCL2, CXCL8 and TNFalpha were measured in patients with pulmonary tuberculosis (N = 12), extra-pulmonary tuberculosis (N = 8) and BCG-vaccinated healthy volunteers (N = 12). Whole blood cells were stimulated with non-pathogenic Mycobacterium bovis bacille-Calmette Guerin (BCG) vaccine strain or bacterial lipopolysaccharide (LPS) and cyto/chemokines were monitored in supernatants., Results: Circulating serum levels of CXCL8 and TNFalpha were raised in all tuberculosis patients, while CCL2 levels were not. There was no difference in spontaneous cytokine secretion from whole blood cells between patients and controls. M. bovis BCG-induced ex vivo CCL2 secretion was significantly greater in pulmonary as compared with both extra-pulmonary tuberculosis patients and endemic controls. In response to LPS stimulation, patients with pulmonary tuberculosis showed increased CCL2 and TNFalpha responses as compared with the extra-pulmonary group. BCG-, and LPS-induced CXCL8 secretion was comparable between patients and controls., Conclusion: CCL2 is activated by TNFalpha and is essential for recruitment of monocytes and T cells to the site of mycobacterial infection. Increased CCL2 activation in pulmonary tuberculosis may result in a stronger cellular response as compared with extra-pulmonary tuberculosis patients, and this may contribute to the localization of infection to the pulmonary site.

Whole-blood assays (WB) provide a simple tool for assessing immune cytokine profiles which may be useful laboratory predictors of early disease, aiding the evaluation of new tuberculosis (TB) vaccines and offering insights into disease pathogenesis. Although BCG does not provide protection against pulmonary disease in TB endemic areas, it does modulate immune responses to mycobacterial antigens. It is important, therefore, to evaluate any new tool in an endemic setting in both BCG vaccinees and patients with tuberculosis. We have assessed the optimal conditions in terms of dose and kinetics of those cytokines which are released early (TNF-alpha, IL6 and TGF-beta, IL10) or (interferon [IFN]-gamma and IL5) in WB cultures stimulated with mitogens and mycobacterial antigens. Responses were studied in parallel in untreated TB patients and endemic control groups. Optimal responses to LPS (predominantly monocyte-derived) occurred on days 1-2, whereas for PHA (predominantly T-cell-derived), they were on days 3-5. Secreted Mycobacterium tuberculosis culture filtrate proteins (CFP) provided a stronger stimulus for monocyte-derived cytokines compared to PPD, but both antigens were comparable for induction of T-cell cytokines. Using unpaired Student's t-tests, pulmonary tuberculosis patients (P.TB; n=11), in response to CFP, showed higher monocyte-derived IL6 (p=0.023) and IL10 (p=0.042) compared to endemic controls (EC; n=13), and significantly suppressed T-cell-derived IFN-gamma (p=0.028) and IL5 (p=0.012) secretion but increased IL10 (p=0.047) on day 5, indicating that CFP is a strong stimulus for IL10 secretion in pulmonary TB patients. Extrapulmonary TB patients (E.TB; n=6) showed no elevation of early monocyte-derived cytokines to either PPD or CFP, but showed a marked suppression of the T-cell-derived cytokines IFN-gamma (PPD, p=0.015; CFP, p=0.05) and IL5 (PPD, p=0.05; CFP, p=0.015). Cytokine analysis in WB cultures is, therefore, able to discriminate between active tuberculosis infection and nondiseased healthy controls.

BackgroundTens of millions of children are exposed to Mycobacterium tuberculosis globally every year; however, there are no contemporary estimates of the risk of developing tuberculosis in exposed children. The effectiveness of contact investigations and preventive therapy remains poorly understood.MethodsIn this systematic review and meta-analysis, we investigated the development of tuberculosis in children closely exposed to a tuberculosis case and followed for incident disease. We restricted our search to cohort studies published between Jan 1, 1998, and April 6, 2018, in MEDLINE, Web of Science, BIOSIS, and Embase electronic databases. Individual-participant data and a pre-specified list of variables were requested from authors of all eligible studies. These included characteristics of the exposed child, the index case, and environmental characteristics. To be eligible for inclusion in the final analysis, a dataset needed to include: (1) individuals below 19 years of age; (2) follow-up for tuberculosis for a minimum of 6 months; (3) individuals with household or close exposure to an individual with tuberculosis; (4) information on the age and sex of the child; and (5) start and end follow-up dates. Studies assessing incident tuberculosis but without dates or time of follow-up were excluded. Our analysis had two primary aims: (1) estimating the risk of developing tuberculosis by time-period of follow-up, demographics (age, region), and clinical attributes (HIV, tuberculosis infection status, previous tuberculosis); and (2) estimating the effectiveness of preventive therapy and BCG vaccination on the risk of developing tuberculosis. We estimated the odds of prevalent tuberculosis with mixed-effects logistic models and estimated adjusted hazard ratios (HRs) for incident tuberculosis with mixed-effects Poisson regression models. The effectiveness of preventive therapy against incident tuberculosis was estimated through propensity score matching. The study protocol is registered with PROSPERO (CRD42018087022).FindingsIn total, study groups from 46 cohort studies in 34 countries-29 (63%) prospective studies and 17 (37%) retrospective-agreed to share their data and were included in the final analysis. 137 647 tuberculosis-exposed children were evaluated at baseline and 130 512 children were followed for 429 538 person-years, during which 1299 prevalent and 999 incident tuberculosis cases were diagnosed. Children not receiving preventive therapy with a positive result for tuberculosis infection had significantly higher 2-year cumulative tuberculosis incidence than children with a negative result for tuberculosis infection, and this incidence was greatest among children below 5 years of age (19·0% [95% CI 8·4-37·4]). The effectiveness of preventive therapy was 63% (adjusted HR 0·37 [95% CI 0·30-0·47]) among all exposed children, and 91% (adjusted HR 0·09 [0·05-0·15]) among those with a positive result for tuberculosis infection. Among all children

Background Mycobacterium tuberculosis infects nearly 1/3 of the world population and this reservoir forms the largest pool from which new cases arise. Among the cytokines, IFN-γ is a key determinant in protection against tuberculosis. Single nucleotide polymorphisms (SNPs) in IFN-γ gene (+874 T/A) which determine TT high (hi), AA low (lo) and TA intermediate (int) responder phenotypes have shown variable associations with tuberculosis disease outcome in different ethnic populations. The objective of the current study was to analyze IFN-γ gene combinations with other IFN-γ regulating cytokine genes (IL-10, TNF -α, IL-6) to see the effect of gene- combinations on disease severity outcome in pulmonary tuberculosis. Methods and Findings Study groups comprised of pulmonary TB patients stratified according to lung tissue involvement into mild (Pmd = 74) or advance (Pad = 23) lung disease and compared with healthy controls (TBNA = 166). Genotype analysis was carried out using amplification refractory mutation system-PCR (ARMS-PCR). IFN-γ gene (+874 T/A) functional SNP combinations in TNFα (-308 G/A), IL-10 (-1082 A/G) and IL-6 (-174 G/C) were analyzed. Single gene analysis (Pearson Χ2) showed a dominant association of IFN-γ TT hi genotype (p = 0.001) and T allele (p = 0.001) with mild disease. IFN-γlo -IL-10lo genotype combination was associated with advanced disease (p = 0.002). IFN-γhi -IL-6 hi combination was associated with mild disease (p = 0.0005) while IFN-γlo -IL-6 int was associated with protection against both forms of pulmonary disease (p = 0.002). Conclusion Our results show that a limited number of IFN-γ gene combinations with other cytokine functional SNPs determine the outcome of disease severity in tuberculosis. [ABSTRACT FROM AUTHOR]

Background: A high prevalence (50-80%) of Tuberculin Skin Test Positivity (TST+ ≥10 mm indurations) has been reported in TB endemic countries. This pool forms a huge reservoir for new incident TB cases. However, immune biomarkers associated with TST conversion are largely unknown. The objective of this study was to identify immune biomarkers associated with TST conversion after acute Mycobacterium tuberculosis (MTB) exposure. Methodology/Principal Findings: A 24 month longitudinal study was carried out in a recently MTB exposed cohort of household contacts (HC = 93; 75% TST+). Control group consisted of unexposed community controls (EC = 59; 46%TST+). Cytokine secretion was assessed in whole blood cultures in response to either mycobacterial culture filtrate (CF) antigens or mitogens (PHA or LPS) using Elisa methodology. Compared to the EC group, the HC group at recruitment (Kruskal-Wallis Test) showed significantly suppressed IFN γ (p = 0.0001), raised IL-10 (p = 0.0005) and raised TNF α (p = 0.001) in response to CF irrespective of their TST status. Seventeen TST-HC, showed TST conversion when retested at 6 months. Post TST conversion (paired t tests) significant increases were observed for CF induced IFN γ (p = 0.038), IL-10 (p = 0.001) and IL-6 (p = 0.006). Cytokine responses were also compared in the exposed HC group with either recent infection [(TST converters (N = 17)] or previous infection [TST+ HC (N = 54)] at 0, 6, 12 and 24 months using ANOVA on repeated measures. Significant differences between the exposed HC groups were noted only at 6 months. CF induced IFN γ was higher in previously infected HC group (p = 0.038) while IL-10 was higher in recently infected HC group (p = 0.041). Mitogen induced cytokine secretion showed similar differences for different group. Conclusions/Significance: Our results suggest that TST conversion is associated with early increases in IFN γ and IL-10 responses and precedes latency by several months post exposure. [ABSTRACT FROM AUTHOR]

Summary: Several cytokines (IFNγ, TNFα, IL10 and IL6) show an association with either disease localization or dissemination in tuberculosis. There are also reports of involvement of extra-pulmonary sites in tuberculosis with differential clinical severity. However, no comparative study of biomarkers across the disease severity spectrum is available. This was the purpose of the current study. Cytokines (IFNγ, TNFα, IL10 and IL6) secreted in response to a panel of stimulants (PHA, LPS or mycobacterial antigens) in whole blood were determined in eighty-two tuberculosis patients. WHO criteria was applied for stratification of patients according to disease severity: disseminated and or severe disease (EPTB1; N=29); disease localized to lung parenchyma (PTB; N=32) and disease localized to peripheral sites without lung involvement (EPTB2; N=21). Mycobacterial antigens induced IFNγ/IL10 ratio showed a direct relationship with disease severity ranking (median ratios: EPTB1=0.21; PTB=0.85; EPTB2=7.7) and the highest correlation (Spearman Rank; rho=0.673, p<0.000001). IFNγ/IL10 ratio also rank ordered clinical severity as it relates to anatomic sites. IFNγ/IL10 ratio may therefore provide a useful objective marker of disease severity in both pulmonary and extra-pulmonary tuberculosis. [Copyright &y& Elsevier]

Mycobacterium leprae (ML) GroES has been shown to induce strong T cell responses in tuberculoid as well as in exposed healthy contacts of leprosy patients, and therefore this antigen has been the focus of study as a potential vaccine candidate. Paradoxically, we have shown that ML GroES also induces extremely high titres of IgG1 antibody in leprosy patients across the disease spectrum, a response associated with disease progression. IgG1 antibodies in leprosy also show a negative association with interferon-γ, a critical T cell cytokine responsible for macrophage activation and intracellular killing of mycobacteria. We therefore queried if antibody and T cell responses were being evoked by different epitopes in ML GroES proteins. To address the issue of epitope recognition in mycobacterial diseases, we have analysed 16 peptides (15-mer peptides) spanning the entire ML and M. tuberculosis GroES protein in leprosy ( n = 19) and tuberculosis ( n = 9) patients and healthy endemic controls ( n = 8). Our analysis demonstrates clearly that the dominant peptides evokingT cell and IgG subclass antibodies were different. The target of both T and B cell responses were cross-reactive epitopes in all groups. Differences in disease and healthy states related to the strength (mean intensity) of the T cell and antibody response. IgG1 and IgG3 antibodies were associated with disseminated disease and IgG 2 and IgG4 with disease limitation. Such comprehensive immune profiling of antigen-specific responses is critical to understanding the disease pathogenesis and also if these reagents are to be exploited for either diagnostic or vaccine purposes. [ABSTRACT FROM AUTHOR]

To assess the association between vitamin D deficiency and tuberculosis disease progression, we studied vitamin D levels in a cohort of tuberculosis patients and their contacts (N = 129) in Pakistan. Most (79%) persons showed deficiency. Low vitamin D levels were associated with a 5-fold increased risk for progression to tuberculosis. [ABSTRACT FROM AUTHOR]