Low body mass index is associated with diminished plasma cytokines and chemokines in both active and latent tuberculosis.

Introduction: Low body mass index (BMI) is a major risk factor for tuberculosis (PTB). Low BMI can impair the immune system and thus might affect TB incidence. Methods: We examined the plasma levels of Type 1, Type 17, pro-inflammatory, Type 2 and regulatory cytokines and CC and CXC chemokines in PTB and latent TB (LTB) individuals with low BMI (LBMI) or normal BMI (NBMI). Results: Our data show that PTB is associated with significantly lower levels of IFNγ, TNFα, IL-2, IL-17A, IL-6, IL-12, IL-4 and IL-5 cytokines but significantly higher levels of IL-10, TGFß and GM-CSF in LBMI compared to NBMI. Similarly, PTB is also associated with significantly lower levels of CCL2, CCL3, CCL11, CXCL1, CXCL9 and CXCL10 chemokines in LBMI compared to NBMI. Our data reveals that LTB is associated with significantly lower levels of IFNγ, TNFα, IL-2, IL1ß, IL-12, IL-13 cytokines but significantly higher levels of IL-10, TGFß, IL-4 and IL-22 in LBMI compared to NBMI. Similarly, LTB is also associated with significantly lower levels of CCL2, CXCL1, CXCL9 and CXCL10 and significantly higher levels of CCL1, CCL3, and CCL4 in LBMI compared to NBMI. Conclusion: Thus, LBMI has a major impact on the cytokine and chemokine milieu of both PTB and LTB and might predispose to the increased risk of tuberculosis by this immunomodulatory effect.

Plasma Chemokines Are Baseline Predictors of Unfavorable Treatment Outcomes in Pulmonary Tuberculosis.

BACKGROUND: Plasma chemokines are biomarkers of greater disease severity, higher bacterial burden, and delayed sputum culture conversion in pulmonary tuberculosis (PTB). Whether plasma chemokines could also serve as biomarkers of unfavorable treatment outcomes in PTB is not known. METHODS: A cohort of newly diagnosed, sputum smear- and culture-positive adults with drug-sensitive PTB were recruited under the Effect of Diabetes on Tuberculosis Severity study in Chennai, India. Plasma chemokine levels measured before treatment initiation were compared between 68 cases with unfavorable outcomes (treatment failure, death, or recurrence) and 136 control individuals who had recurrence-free cure. A second validation cohort comprising newly diagnosed, culture-positive adults with drug-sensitive TB was used to measure plasma chemokine levels in 20 cases and 40 controls. RESULTS: Six chemokines (CCL2, CCL3, CCL4, CXCL8, CXCL10, and CX3CL1) were associated with increased risk, while CXCL1 was associated with decreased risk of unfavorable outcomes in unadjusted and adjusted analyses in the test cohort. Similarly, CCL3, CXCL8, and CXCL10 were associated with increased risk of unfavorable treatment outcomes in the validation cohort. Receiver operating characteristic analysis revealed that combinations of CCL3, CXCL8, and CXCL10 exhibited very high sensitivity and specificity in differentiating cases vs controls. CONCLUSIONS: Our study reveals a plasma chemokine signature that can be used as a novel biomarker for predicting adverse treatment outcomes in PTB.

Association of Plasma Matrix Metalloproteinase and Tissue Inhibitors of Matrix Metalloproteinase Levels With Adverse Treatment Outcomes Among Patients With Pulmonary Tuberculosis.

Importance: Identifying biomarkers of treatment response is an urgent need in the treatment of tuberculosis (TB). Matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) are potential diagnostic biomarkers in pulmonary TB (PTB). Objective: To assess whether baseline plasma levels of MMPs and TIMPs are also prognostic biomarkers for adverse treatment outcomes in patients with PTB. Design, Setting, and Participants: Two different cohorts (test and validation) of individuals with PTB were recruited from 2 different sets of primary care centers in Chennai, India, and were followed up for treatment outcomes. Participants were individuals with newly diagnosed TB that was sputum smear and culture positive and drug sensitive. A total of 68 cases and 133 controls were in the test cohort and 20 cases and 40 controls were in the validation cohort. A nested case-control study was performed by matching case patients to control participants in a 1:2 ratio for age, sex, and body mass index. Data for the test cohort was taken from a study performed from 2014 to 2019, and data for the validation cohort, from a study performed from 2008 to 2012. The data analysis was performed from November 2019 to May 2020. Interventions: Individuals with PTB were treated with antituberculosis chemotherapy for 6 months and followed up for 1 year after completion of treatment. Main Outcomes and Measures: Individuals with PTB with adverse outcomes (treatment failure, all-cause mortality, or recurrent TB) were defined as cases and those with favorable outcomes (recurrence-free cure) were defined as controls. Plasma levels of MMPs and TIMPs were measured before treatment as potential biomarkers. Results: In all, 68 cases and 133 matched controls were enrolled in the study (170 [85%] males and 31 [15%] females; median age, 45 years [range, 23-73 years]) in the test cohort and 20 cases with 40 matched controls (51 [85%] males and 9 [15%] females; median age, 45 years [range, 19-61 years]) in the validation cohort. Baseline plasma levels of 5 MMPs and 2 TIMPs in the test cohort and 5 MMPs and all 4 TIMPS in the validation cohort were significantly higher in cases vs controls. In the test cohort, the geometric means (GMs), cases vs controls, were as follows: for MMP-1, 3680 vs 2484 pg/mL (P = .008); for MMP-2, 6523 vs 4762 pg/mL (P < .001); for MMP-7, 3346 vs 2100 pg/mL (P < .001); for MMP-8, 1915 vs 1066 pg/mL (P < .001); for MMP-9, 2774 vs 2336 pg/mL (P = .009); for TIMP-1, 4491 vs 2910 pg/mL (P < .001); and for TIMP-2, 3082 vs 2115 pg/mL (P < .001). In the validation cohort, the GMs, cases vs controls were as follows: for MMP-1, 3680 vs 2484 pg/mL (P < .001); for MMP-2, 6523 vs 4762 pg/mL (P < .001); for MMP-7, 3346 vs 2100 pg/mL (P < .001); for MMP-9, 1915 vs 1066 pg/mL (P < .001); for MMP-13, 2774 vs 2336 pg/mL (P < .001); for TIMP-1, 4491 vs 2910 pg/mL (P = .003); for TIMP-2, 3082 vs 2115 pg/mL (P = .003); for TIMP-3, 2066 vs 1020 pg/mL (P < .001); and for TIMP-4, 2130 vs 694 pg/mL (P < .001). Plasma levels of MMPs and TIMPs were associated with increased risk of adverse outcomes according to both univariate and multivariable analysis in the test cohort (eg, univariate analysis: odds ratio [OR] for MMP-8, 2.04; 95% CI, 1.33-3.14; P = .001; multivariable analysis: OR for MMP-8, 2.16; 95% CI, 1.34-3.47; P = .001). Combined receiver operating characteristic analysis revealed significant area under the curve (AUC), with high sensitivity and specificity in both cohorts (eg, for a combination of MMP-2, MMP-7, and TIMP-1 in the test cohort: sensitivity, 84%; specificity, 83%; and AUC, 0.886; for a combination of MMP-2, MMP-7, TIMP-1, and TIMP-2 in the validation cohort: sensitivity, 85%; specificity, 95%; and AUC, 0.944). Conclusions and Relevance: Baseline plasma MMP and TIMP levels may be correlates of risk and prognostic biomarkers for treatment failure, relapse, and death in individuals with PTB and merit further evaluation as predictive biomarkers for stratification of patients to shortened or intensified treatment regimens.

Filarial Coinfection Is Associated With Higher Bacterial Burdens and Altered Plasma Cytokine and Chemokine Responses in Tuberculous Lymphadenitis.

Filarial infections are known to modulate cytokine responses in pulmonary tuberculosis by their propensity to induce Type 2 and regulatory cytokines. However, very little is known about the effect of filarial infections on extra-pulmonary forms of tuberculosis. Thus, we have examined the effect of filarial infections on the plasma levels of various families of (IL-1, IL-12, γC, and regulatory) cytokines and (CC and CXC) chemokines in tuberculous lymphadenitis coinfection. We also measured lymph node culture grades in order to assess the burden of Mycobacterium tuberculosis in the two study groups [Fil+ (n = 67) and Fil- (n = 109)]. Our data reveal that bacterial burden was significantly higher in Fil+ compared to Fil- individuals. Plasma levels of IL-1 family (IL-1α, IL-ß, IL-18) cytokines were significantly lower with the exception of IL-33 in Fil+ compared to Fil- individuals. Similarly, plasma levels of IL-12 family cytokines -IL-12 and IL-23 were significantly reduced, while IL-35 was significantly elevated in Fil+ compared to Fil- individuals. Filarial infection was also associated with diminished levels of IL-2, IL-9 and enhanced levels of IL-4, IL-10, and IL-1Ra. Similarly, the Fil+ individuals were linked to elevated levels of different CC (CCL-1, CCL-2, CCL-3, CCL-11) and CXC (CXCL-2, CXCL-8, CXCL-9, CXCL-11) chemokines. Therefore, we conclude that filarial infections exert powerful bystander effects on tuberculous lymphadenitis, effects including modulation of protective cytokines and chemokines with a direct impact on bacterial burdens.

Strongyloides stercoralis Coinfection Is Associated With Greater Disease Severity, Higher Bacterial Burden, and Elevated Plasma Matrix Metalloproteinases in Pulmonary Tuberculosis.

BACKGROUND: Helminths and tuberculosis (TB) largely overlap at the population level. Whether helminth infections influence disease severity and bacterial burdens in TB is not well understood. METHODS: This study was conducted to examine the disease severity in a cohort of pulmonary TB (PTB) individuals with (Ss+) or without (Ss-) seropositivity for Strongyloides stercoralis infection. RESULTS: Ss+ was associated with increased risk of cavitation (odds ratio [OR], 4.54; 95% confidence interval [CI], 2.33-9.04; P < .0001) and bilateral lung involvement (OR, 5.97; 95% CI, 3.03-12.09; P < .0001) in PTB individuals. Ss+ was also associated with higher bacterial burdens (OR, 7.57; 95% CI, 4.18-14.05; P < .0001) in PTB individuals. After multivariate analysis adjusting for covariates, Ss+ was still associated with greater risk of cavitation (adjusted OR [aOR], 3.99; 95% CI, 1.73-9.19; P = .0014), bilateral lung involvement (aOR, 4.09; 95% CI, 1.78-9.41; P = .0011), and higher bacterial burden (aOR, 9.32; 95% CI, 6.30-13.96; P < .0001). Finally, Ss+ was also associated with higher plasma levels of matrix metalloproteinases ([MMP]-1, -2, -7, -8, and -9) in PTB individuals. CONCLUSIONS: Therefore, our data demonstrate that coexistent Ss infection is associated with greater disease severity and higher bacterial burden in PTB. Our data also demonstrate enhanced plasma levels of MMPs in coinfected individuals, suggesting a plausible biological mechanism for these effects.

Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases Are Potential Biomarkers of Pulmonary and Extra-Pulmonary Tuberculosis.

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) are potential regulators of tuberculosis (TB) pathology. Whether they are candidates for non-sputum-based biomarkers for pulmonary TB (PTB) and extra-pulmonary TB (EPTB) is not fully understood. Hence, to examine the association of MMPs and TIMPs with PTB and EPTB, we have measured the circulating levels of MMPs (MMP-1, 2, 3, 7, 8, 9, 12, and 13) and TIMPs (TIMP-1, 2, 3, and 4) in PTB, EPTB and compared them with latent tuberculosis (LTB) or healthy control (HC) individuals. We have also assessed their circulating levels before and after the completion of anti-tuberculosis treatment (ATT). Our data describes that systemic levels of MMP-1, 8, 9, 12 were significantly increased in PTB compared to EPTB, LTB, and HC individuals. In contrast, MMP-7 was significantly reduced in PTB compared to EPTB individuals. Likewise, the systemic levels of MMP-1, 7, 13 were significantly increased in EPTB in comparison to LTB and HC individuals. In contrast, MMP-8 was significantly reduced in EPTB individuals compared to LTB and HC individuals. In addition, the systemic levels of TIMP-1, 2, 3 were significantly diminished and TIMP-4 levels were significantly enhanced in PTB compared to EPTB, LTB, and HC individuals. The circulating levels of TIMP-2 was significantly reduced and TIMP-3 was significantly elevated in EPTB individuals in comparison with LTB and HCs. Some of the MMPs (7, 8, 9, 12, 13 in PTB and 1, 7, 8, 9 in EPTB) and TIMPs (1, 2, 3, 4 in PTB and 4 in EPTB) were significantly modulated upon treatment completion. ROC analysis showed that MMP-1, 9 and TIMP-2, 4 could clearly discriminate PTB from EPTB, LTB and HCs and MMP-13 and TIMP-2 could clearly discriminate EPTB from LTB and HCs. Additionally, multivariate analysis also indicated that these alterations were independent of age and sex in PTB and EPTB individuals. Therefore, our data demonstrates that MMPs and TIMPs are potential candidates for non-sputum-based biomarkers for differentiating PTB and EPTB from LTB and HC individuals.

Heightened systemic levels of anti-inflammatory cytokines in pulmonary tuberculosis and alterations following anti-tuberculosis treatment.

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, TGFß) 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 TGFß 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.

Plasma Proinflammatory Cytokines Are Markers of Disease Severity and Bacterial Burden in Pulmonary Tuberculosis.

BACKGROUND: Type 1, type 17, and other proinflammatory cytokines are important in host immunity to tuberculosis (TB) in animal models. However, their role in human immunity to TB is not completely understood. METHODS: To examine the association of proinflammatory cytokines with pulmonary TB (PTB), we examined the plasma levels of type 1 (interferon [IFN]γ and tumor necrosis factor [TNF]α), type 17 (interleukin [IL]-17A and IL-17F), and other proinflammatory (IL-6, IL-12, and IL-1ß) cytokines in individuals with PTB, latent TB (LTB), or healthy controls (HC). RESULTS: Individuals with PTB exhibited significantly higher plasma levels of most of the above cytokines compared with LTB or HC individuals. Principal component analysis based on these cytokines could clearly distinguish PTB from both LTB or HC individuals. Pulmonary TB individuals with bilateral or cavitary disease exhibited significantly higher levels of IFNγ, TNFα, IL-17A, and IL-1ß compared with those with unilateral or noncavitary disease. Pulmonary TB individuals also exhibited a significant positive relationship between IFNγ, TNFα, and IL-17A levels and bacterial burdens. In addition, PTB individuals with delayed culture conversion exhibited significantly higher levels of IFNγ, TNFα, IL-17A, and IL-1ß at baseline. Finally, the plasma levels of all the cytokines examined were significantly reduced after successful chemotherapy. CONCLUSIONS: Therefore, our data demonstrate that PTB is associated with heightened levels of plasma proinflammatory cytokines, which are reversed after chemotherapy. Our data also reveal that proinflammatory cytokines are markers of disease severity, bacterial burden, and delayed culture conversion in PTB.

Altered circulating levels of B cell growth factors and their modulation upon anti-tuberculosis treatment in pulmonary tuberculosis and tuberculous lymphadenitis.

B cell activating factor/a proliferation-inducing ligand (BAFF/APRIL) are members of the tumor necrosis factor alpha (TNF) α family of ligands, which are essential for B cell survival, development, and modulation of the immune system. To examine the association of circulating levels of BAFF and APRIL with pulmonary tuberculosis (PTB) and tuberculous lymphadenitis (TBL), we measured the systemic levels of APRIL and BAFF in individuals with PTB, TBL, latent tuberculosis (LTB) and healthy controls (HC). Further, we also examined the pre and post-treatment plasma levels of above-mentioned parameters in PTB and TBL individuals upon completion of anti-TB chemotherapy. Next, the association of these cytokines either with extent of disease, disease severity, bacterial burden in PTB and lymph node culture grade or the lymph node size in TBL was also assessed. Finally, ROC analysis was performed to examine the discrimination capacity of APRIL and BAFF between PTB or TBL with LTB. Our study revealed significantly diminished plasma levels of APRIL in PTB and higher plasma levels of BAFF in both PTB and TBL individuals compared to LTB and HC. Furthermore, we observed a significant increase in APRIL levels in TBL and significantly decreased plasma levels of BAFF in both PTB and TBL after the completion of successful anti-TB treatment. There was no statistically positive relationship between BAFF and APRIL levels and the extent of disease, disease severity and bacterial burden in PTB. In TBL, there was a significant correlation between APRIL (but not BAFF) levels with lymph node culture grades. In contrast, APRIL in PTB and BAFF in TBL were able to clearly discriminate from LTB in ROC analysis. In summary, our results showed altered levels of BAFF/APRIL and their modulation upon chemotherapy, suggesting that these cytokines might be involved in the immune-modulation of TB infection.

Altered Systemic Adipokine Levels in Pulmonary Tuberculosis and Changes following Treatment.

Pulmonary tuberculosis (PTB) is associated with modulation of levels of adipokines, specifically adiponectin and leptin, but the effect of standard antituberculosis treatment (ATT) on the systemic levels of adiponectin, resistin, and leptin has not been well explored. To identify the association of adipokines with PTB and their relationship with disease severity and bacterial burden, we measured the levels of adiponectin, resistin, and leptin in PTB individuals and compared them with latent tuberculosis (LTB) and healthy control (HC) individuals. Pulmonary tuberculosis was characterized by diminished circulating levels of adiponectin and leptin and heightened circulating levels of resistin in comparison to that in LTB and HC individuals. However, PTB with bilateral or cavitary disease did not exhibit any increased systemic levels of these adipokines in comparison with those with unilateral or non-cavitary disease, respectively. In addition, none of the adipokines exhibited a positive correlation with bacterial burdens, but adiponectin alone exhibited a negative correlation with body mass index in PTB individuals. Finally, on successful completion of ATT, PTB individuals exhibited significantly increased levels of adiponectin and leptin and significantly decreased levels of resistin. Therefore, our data identify an important association of systemic adipokine levels with PTB disease and its alteration following ATT.

Heightened Systemic Levels of Neutrophil and Eosinophil Granular Proteins in Pulmonary Tuberculosis and Reversal following Treatment.

Granulocytes are activated during Mycobacterium tuberculosis infection and act as immune effector cells, and granulocyte responses are implicated in tuberculosis (TB) pathogenesis. Plasma levels of neutrophil and eosinophil granular proteins provide an indirect measure of degranulation. In this study, we wanted to examine the levels of neutrophil and eosinophil granular proteins in individuals with pulmonary tuberculosis (PTB) and to compare them with the levels in individuals with latent TB (LTB). Hence, we measured the plasma levels of myeloperoxidase (MPO), neutrophil elastase, proteinase 3, major basic protein (MBP), eosinophil-derived neurotoxin (EDN), eosinophil cationic protein (ECP), and eosinophil peroxidase (EPX) in these individuals. Finally, we also measured the levels of all of these proteins in PTB individuals following antituberculosis treatment (ATT). Our data reveal that PTB individuals are characterized by significantly higher plasma levels of MPO, elastase, proteinase 3, as well as MBP and EDN in comparison to those in LTB individuals. Our data also reveal that ATT resulted in the reversal of all of these changes, indicating an association with TB disease. Finally, our data show that the systemic levels of MPO and proteinase 3 can significantly discriminate PTB from LTB individuals. Thus, our data suggest that neutrophil and eosinophil granular proteins could play a potential role in the innate immune response and, therefore, the pathogenesis of pulmonary TB.

Modulation of Th1/Tc1 and Th17/Tc17 responses in pulmonary tuberculosis by IL-20 subfamily of cytokines.

Although IL-10 is known to be an important cytokine in the immune response to TB, very little is known about the role of IL-20 subfamily of cytokines in the host response to TB. To identify the role of CD4+ T and CD8+ T cells producing IL-20 subfamily of cytokines in human TB, we enumerated the frequencies of IL-10, IL-19 and IL-24 expressing CD4+ and CD8+ T cells following Mtb-specific antigen stimulation of cells from individuals with pulmonary TB (PTB) and latent TB (LTB). We first demonstrated that Mtb-specific antigen induce an expansion of CD4+ and CD8+ T cells expressing IL-10, IL-19 and IL-24 in PTB and LTB individuals, with frequencies being significantly higher in PTB. Next, we demonstrated that IL-10, IL-19 and IL-24 play an important role in the regulation of CD4+ and CD8+ T cells expressing Th1/Tc1 and Th17/Tc17 cytokines in PTB but not LTB individuals. Thus, active PTB is characterized by an IL-10, IL-19 and IL-24 mediated down modulation of Th1/Tc1 and/or Th17/Tc17 cytokines in CD4+ and CD8+ T cell subsets. This suggests that the IL-20 subfamily of cytokines, similar to IL-10 might play a potentially crucial role in the modulation of T cell responses in active TB disease.

Modulation of iron status biomarkers in tuberculosis-diabetes co-morbidity.

Tuberculosis (TB) and diabetes mellitus (DM) remain vital disease burdens in developing countries and the dual burden of DM and TB clearly signifies a growing global public health concern. While modulation of iron status biomarkers in TB is well described, very little is known about the association of these markers with TB-DM. To examine the association of circulating iron status biomarkers in TB disease, we examined the systemic levels of ferritin, hepcidin, soluble transferrin receptor (sTfR), transferrin, apotransferrin and hemopexin in pulmonary TB (PTB) individuals with DM (PTB-DM), without DM (PTB) and those with diabetes only (DM). Circulating levels of ferritin and hepcidin were significantly enhanced in PTB-DM and PTB compared to the DM group. On the other hand, the circulating levels of transferrin and apotransferrin were significantly diminished in PTB-DM and PTB compared to the DM group. The levels of ferritin and hepcidin exhibited a significant positive relationship with HbA1c, whereas apotransferrin exhibited negative relationship with HbA1c in PTB-DM and PTB. ROC analysis revealed that ferritin, hepcidin and transferrin are markers that can distinguish PTB-DM from DM individuals. Our results suggest that some of these circulating iron status markers could prove useful as biomarkers to monitor disease severity.

Diminished plasma levels of common γ-chain cytokines in pulmonary tuberculosis and reversal following treatment.

BACKGROUND: The immune response to tuberculosis (TB) is T cell dependent. T cells are the major facilitators of protection and effector functions with CD4+ T cells being the most important players, followed by CD8+ T cells. The common γ-chain cytokines IL-2, IL-7, IL-15, and IL-21 play a vital role in peripheral T cell growth and survival. However, the role of common γ-chain cytokines in pulmonary TB (PTB) is poorly understood. AIM AND METHODS: To examine the association of circulating common γ-chain cytokines with TB disease or infection, we examined the systemic levels of IL-2, IL-7, IL-15, and IL-21 in individuals with PTB, latent TB (LTB) or no TB infection (NTB). We also examined the levels of these cytokines in PTB individuals before and after anti-tuberculosis treatment. RESULTS: Circulating levels of IL-2, IL-7 and IL-21 were significantly diminished in PTB compared to LTB or NTB individuals. Moreover, TB antigen stimulated whole blood also exhibited diminished levels of common γ-chain cytokines in PTB compared to LTB or NTB individuals. The plasma levels of common γ-chain cytokines exhibited no significant association with the severity or extent of TB disease or with bacterial burdens. However, upon standard anti-TB treatment, both the systemic as well as the TB antigen stimulated levels of IL-2, IL-7 and IL-21 were significantly increased in PTB individuals. CONCLUSION: Therefore our data demonstrate that diminished levels of common γ-chain cytokines are a common characteristic of PTB and potentially highlight the importance of boosting these responses to improve treatment outcomes.

Tuberculous Lymphadenitis Is Associated with Enhanced Baseline and Antigen-Specific Induction of Type 1 and Type 17 Cytokines and Reduced Interleukin-1ß (IL-1ß) and IL-18 at the Site of Infection.

Tuberculous lymphadenitis (TBL) is characterized by an expansion of Th1 and Th17 cells with altered serum levels of proinflammatory cytokines. However, the cytokine profile at the site of infection, i.e., the affected lymph nodes, has not been examined in detail. To estimate the baseline and mycobacterial antigen-stimulated concentrations of type 1, type 17, and other proinflammatory cytokines in patients with TBL (n = 14), we examined both the baseline and the antigen-specific concentrations of these cytokines before and after chemotherapy and compared them with those in individuals with pulmonary tuberculosis (PTB) (n = 14). In addition, we also compared the cytokine responses in whole blood and those in the lymph nodes of TBL individuals. We observed significantly enhanced baseline and antigen-specific levels of type 1 cytokines (gamma interferon [IFN-γ] and tumor necrosis factor alpha [TNF-α]) and a type 17 cytokine (interleukin-17 [IL-17]) and significantly diminished baseline and antigen-specific levels of proinflammatory cytokines (IL-1ß and IL-18) in the whole blood of TBL individuals compared to those in the whole blood of PTB individuals. Moreover, we also observed a pattern of baseline and antigen-specific cytokine production at the site of infection (lymph node) similar to that in the whole blood of TBL individuals. Following standard antituberculosis (anti-TB) treatment, we observed alterations in the baseline and/or antigen-specific levels of IFN-γ, TNF-α, IL-1ß, and IL-18. TBL is therefore characterized by enhanced baseline and antigen-specific production of type 1 and type 17 cytokines and reduced baseline and antigen-specific production of IL-1ß and IL-18 at the site of infection.

Circulating Angiogenic Factors as Biomarkers of Disease Severity and Bacterial Burden in Pulmonary Tuberculosis.

BACKGROUND: Angiogenesis and lymphangiogenesis are classical features of granuloma formation in pulmonary tuberculosis (PTB). In addition, the angiogenic factor--VEGF-A is a known biomarker for PTB. AIMS/METHODOLOGY: To examine the association of circulating angiogenic factors with PTB, we examined the systemic levels of VEGF-A, VEGF-C, VEGF-D, VEGF-R1, VEGF-R2 and VEGF-R3in individuals with PTB, latent TB (LTB) or no TB infection (NTB). RESULTS: Circulating levels of VEGF-A, VEGF-C andVEGF-R2 were significantly higher in PTB compared to LTB or NTB individuals. Moreover, the levels of VEGF-A, VEGF-C and VEGF-R2 were significantly higher in PTB with bilateral and/or cavitary disease. The levels of these factors also exhibited a significant positive relationship with bacterial burdens in PTB. ROC analysis revealed VEGF-A and VEGF-R2 as markers distinguishing PTB from LTB or NTB. Finally, the circulating levels of all the angiogenic factors examined were significantly reduced following successful chemotherapy. CONCLUSION: Therefore, our data demonstrate that PTB is associated with elevated levels of circulating angiogenic factors, possibly reflecting vascular and endothelial dysfunction. In addition, some of these circulating angiogenic factors could prove useful as biomarkers to monitor disease severity, bacterial burden and therapeutic responses.

Modulation of pro- and anti-inflammatory cytokines in active and latent tuberculosis by coexistent Strongyloides stercoralis infection.

Helminth infections are known to induce modulation of both innate and adaptive immune responses in active and latent tuberculosis (TB). However, the role of helminth infections in modulating systemic cytokine responses in active and latent tuberculosis (LTB) is not known. To define the systemic cytokine levels in helminth-TB coinfection, we measured the circulating plasma levels of Type 1, Type 2, Type 17, other pro-inflammatory and regulatory cytokines in individuals with active TB (ATB) with or without coexistent Strongyloides stercoralis (Ss) infection by multiplex ELISA. Similarly, we also measured the same cytokine levels in individuals with LTB with or without concomitant Ss infection in a cross-sectional study. Our data reveal that individuals with ATB or LTB and coexistent Ss infection have significantly lower levels of Type 1 (IFNγ, TNFα and IL-2) and Type 17 (IL-17A and IL-17F) cytokines compared to those without Ss infection. In contrast, those with ATB and LTB with Ss infection have significantly higher levels of the regulatory cytokines (IL-10 and TGFß), and those with LTB and Ss infection also have significantly higher levels of Type 2 cytokines (IL-4, IL-5 and IL-13) as well. Finally, those with LTB (but not ATB) exhibit significantly lower levels of other pro-inflammatory cytokines (IFNα, IFNß, IL-6, IL-12 and GM-CSF). Our data therefore reveal a profound effect of Ss infection on the systemic cytokine responses in ATB and LTB and indicate that coincident helminth infections might influence pathogenesis of TB infection and disease.

IL-27 and TGFß mediated expansion of Th1 and adaptive regulatory T cells expressing IL-10 correlates with bacterial burden and disease severity in pulmonary tuberculosis.

CD4(+) T cell expression of IL-10 is an important mechanism controlling immunity to tuberculosis (TB). To identify the CD4(+) T cell subsets producing IL-10 in human TB, we enumerated the frequencies of IL-10 expressing CD4(+) T cell subsets following TB-antigen stimulation of cells from individuals with pulmonary (PTB) and latent TB (LTB). We first demonstrate that TB antigens induce an expansion of IL-10 expressing Th1 (IL-10(+), IFNγ(+), T-bet(+)), Th2 (IL-10(+), IL-4(+), GATA-3(+)), Th9 (IL-10(+), IL-9(+), IL-4(-)), Th17 (IL-10(+), IL-17(+), IFNγ(-)), and natural and adaptive regulatory T cells [nTregs; IL-10(+), CD4(+), CD25(+), Foxp3(+) and aTregs; IL-10 single(+), CD4(+), CD25(-), Foxp3(-)] in PTB and LTB individuals, with frequencies being significantly higher in the former. However, only Th1 cells and adaptive Tregs expressing IL-10 exhibit a positive relationship with bacterial burdens and extent of disease in PTB. Finally, we show that IL-27 and TGFß play an important role in the regulation of IL-10(+) Th cell subsets. Thus, active PTB is characterized by an IL-27 and TGFß mediated expansion of IL-10 expressing CD4(+) T cell subsets, with IL-10(+) Th1 and IL-10(+) aTreg cells playing a potentially pivotal role in the pathogenesis of active disease.

Type 2 diabetes - Tuberculosis co-morbidity is associated with diminished circulating levels of IL-20 subfamily of cytokines.

IL-20 subfamily of cytokines play an important role in both host defense mechanisms and glucose metabolism. Since, the interaction between tuberculosis (TB) and diabetes (DM) involves both of the above processes, we examined the association of IL-20 subfamily of cytokines in TB-DM co-morbidity. We examined circulating plasma cytokine levels in individuals with active TB with (PTB-DM) or without (PTB) diabetes and also those with latent TB with (LTB-DM) or without (LTB) diabetes. PTB-DM is characterized by diminished circulating levels of IL-19, IL-20, IL-22 and IL-24 but increased levels of IL-10. Similarly, LTB-DM was also characterized by diminished circulating levels of IL-10, IL-19, IL-20 and IL-24 but increased levels of IL-22. Moreover, there was a significant negative correlation of IL-10, IL-19, IL-20, IL-22 and IL-24 levels with hemoglobin A1C (HbA1c) levels in both PTB and/or LTB individuals. Finally, PTB is characterized by diminished levels of IL-19, IL-20, IL-22 and IL-24 in comparison to LTB individuals. Our data reveal that coincident diabetes in either PTB or LTB is characterized by decreased production of the IL-20 subfamily of cytokines and suggest that these cytokines might play an important role in pathogenesis or protection.

Heme Oxygenase-1 Regulation of Matrix Metalloproteinase-1 Expression Underlies Distinct Disease Profiles in Tuberculosis.

Pulmonary tuberculosis (TB) is characterized by oxidative stress and lung tissue destruction by matrix metalloproteinases (MMPs). The interplay between these distinct pathological processes and the implications for TB diagnosis and disease staging are poorly understood. Heme oxygenase-1 (HO-1) levels were previously shown to distinguish active from latent TB, as well as successfully treated Mycobacterium tuberculosis infection. MMP-1 expression is also associated with active TB. In this study, we measured plasma levels of these two important biomarkers in distinct TB cohorts from India and Brazil. Patients with active TB expressed either very high levels of HO-1 and low levels of MMP-1 or the converse. Moreover, TB patients with either high HO-1 or MMP-1 levels displayed distinct clinical presentations, as well as plasma inflammatory marker profiles. In contrast, in an exploratory North American study, inversely correlated expression of HO-1 and MMP-1 was not observed in patients with other nontuberculous lung diseases. To assess possible regulatory interactions in the biosynthesis of these two enzymes at the cellular level, we studied the expression of HO-1 and MMP-1 in M. tuberculosis-infected human and murine macrophages. We found that infection of macrophages with live virulent M. tuberculosis is required for robust induction of high levels of HO-1 but not MMP-1. In addition, we observed that CO, a product of M. tuberculosis-induced HO-1 activity, inhibits MMP-1 expression by suppressing c-Jun/AP-1 activation. These findings reveal a mechanistic link between oxidative stress and tissue remodeling that may find applicability in the clinical staging of TB patients.