Monocytes/Macrophages in Helminth Infections: Key Players in Host Defence, Inflammation, and Tissue Repair.

Monocytes/macrophages are pivotal in host defense, inflammation, and tissue repair. They are actively engaged during helminth infections, playing critical roles in trapping pathogens, eliminating them, repairing tissue damage, and mitigating type 2 inflammation. These cells are indispensable in preserving physiological equilibrium and overseeing pathogen resistance as well as metabolic processes. Furthermore, these immune cells are influenced by cellular metabolism, which adjusts in response to host-derived factors and environmental cues. They secrete effector molecules crucial for anti-helminthic immunity and healing tissues damaged by parasites. Helminth parasites manipulate the immune regulatory capabilities of monocytes/macrophages by secreting anti-inflammatory mediators to dodge host defenses. Infections, especially with helminths, induce metabolic adaptations involving monocytes/macrophages that can lead to enhanced insulin sensitivity. This review provides a synthesis of the activation and diversity of monocytes/macrophages, their involvement in inflammation, and the latest insights into the strategies of monocyte/macrophage-mediated host defense against helminth infections. It also sheds light on recent discoveries concerning the immune regulatory interactions between monocytes/macrophages and helminth parasites.

Elucidating systemic immune responses to acute and convalescent SARS-CoV-2 infection in children and elderly individuals.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), a causative pathogen of the COVID-19 pandemic, affects all age groups. However, various studies have shown that COVID-19 presentation and severity vary considerably with age. We, therefore, wanted to examine the differences between the immune responses of children with COVID-19 and elderly COVID-19 individuals. METHODS: We analyzed cytokines, chemokines, growth factors, and acute phase proteins in acute and convalescent COVID-19 children and the elderly with acute and convalescent COVID-19. RESULTS: We show that most of the pro-inflammatory cytokines (interferon [IFN]γ, interleukin [IL]-2, tumor necrosis factor-α [TNFα], IL-1α, IFNα, IFNß, IL-6, IL-12, IL-3, IL-7, IL-1Ra, IL-13, and IL-10), chemokines (CCL4, CCL11, CCL19, CXCL1, CXCL2, CXCL8, and CXL10), growth factors (vascular endothelial growth factor and CD40L) and acute phase proteins (C-reactive protein, serum amyloid P, and haptoglobin) were decreased in children with acute COVID 19 as compared with elderly individuals. In contrast, children with acute COVID-19 exhibited elevated levels of cytokines- IL-1ß, IL-33, IL-4, IL-5, and IL-25, growth factors-fibroblast growth factor-2, platelet- derived growth factors-BB, and transforming growth factorα as compared with elderly individuals. Similar, differences were manifest in children and elderly with convalescent COVID-19. CONCLUSION: Thus, COVID-19 children are characterized by distinct cytokine/chemokine/growth factor/acute phase protein markers that are markedly different from elderly COVID-19 individuals.

Alterations of adipokines, pancreatic hormones and incretins in acute and convalescent COVID-19 children.

BACKGROUND: The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), accountable for Coronavirus disease 2019 (COVID-19), may cause hyperglycemia and additional systemic complexity in metabolic parameters. It is unsure even if the virus itself causes type 1 or type 2 diabetes mellitus (T1DM or T2DM). Furthermore, it is still unclear whether even recuperating COVID-19 individuals have an increased chance to develop new-onset diabetes. METHODS: We wanted to determine the impact of COVID-19 on the levels of adipokines, pancreatic hormones, incretins and cytokines in acute COVID-19, convalescent COVID-19 and control children through an observational study. We performed a multiplex immune assay analysis and compared the plasma levels of adipocytokines, pancreatic hormones, incretins and cytokines of children presenting with acute COVID-19 infection and convalescent COVID-19. RESULTS: Acute COVID-19 children had significantly elevated levels of adipsin, leptin, insulin, C-peptide, glucagon and ghrelin in comparison to convalescent COVID-19 and controls. Similarly, convalescent COVID-19 children had elevated levels of adipsin, leptin, insulin, C-peptide, glucagon, ghrelin and Glucagon-like peptide-1 (GLP-1) in comparison to control children. On the other hand, acute COVID-19 children had significantly decreased levels of adiponectin and Gastric Inhibitory Peptide (GIP) in comparison to convalescent COVID-19 and controls. Similarly, convalescent COVID-19 children had decreased levels of adiponectin and GIP in comparison to control children. Acute COVID-19 children had significantly elevated levels of cytokines, (Interferon (IFN)) IFNγ, Interleukins (IL)-2, TNFα, IL-1α, IL-1ß, IFNα, IFNß, IL-6, IL-12, IL-17A and Granulocyte-Colony Stimulating Factors (G-CSF) in comparison to convalescent COVID-19 and controls. Convalescent COVID-19 children had elevated levels of IFNγ, IL-2, TNFα, IL-1α, IL-1ß, IFNα, IFNß, IL-6, IL-12, IL-17A and G-CSF in comparison to control children. Additionally, Principal component Analysis (PCA) analysis distinguishes acute COVID-19 from convalescent COVID-19 and controls. The adipokines exhibited a significant correlation with the levels of pro-inflammatory cytokines. CONCLUSION: Children with acute COVID-19 show significant glycometabolic impairment and exaggerated cytokine responses, which is different from convalescent COVID-19 infection and controls.

Strongyloidiasis stercoralis coinfection is associated with altered iron status biomarkers in tuberculous lymphadenitis.

Soil-transmitted helminth [mainly Strongyloidiasis stercoralis (Ss)] and tuberculous lymphadenitis (TBL) coinfection in humans is a significant public health problem. We have previously shown that TBL+Ss+ coinfection significantly alters diverse cytokine, matrix metalloproteinase, and tissue inhibitors of metalloproteinase profiles. However, no data is available to understand the influence of Ss coinfection in TBL disease with respect to iron status biomarkers. Hence, we have studied the effect of Ss coinfection on the circulating levels of iron status (ferritin, transferrin [TF], apotransferrin [ApoT], hepcidin, hemopexin) biomarkers in TBL disease. Our results show that TBL+Ss+ and/or TBL+Ss- individuals are associated with significantly altered biochemical and hematological (red blood cell (RBC) counts, hemoglobin (Hb), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) were decreased, and platelets were increased) parameters compared to TBL-Ss+ individuals. Our results also show that TBL+Ss+ coinfection is associated with diminished circulating levels of ferritin, ApoT, hepcidin, and hemopexin compared to TBL+Ss- individuals. TBL+Ss+ and TBL+Ss- groups are associated with altered iron status biomarkers (decreased ferritin [TBL+Ss+ alone] and increased TF, ApoT, hepcidin and hemopexin [TBL+Ss- alone]) compared to TBL-Ss+ group. The heat map expression profile and principal component analysis (PCA) analysis of iron status biomarkers were significantly altered in TBL+Ss+ compared to TBL+Ss- and/or TBL-Ss+ individuals. A significant correlation (positive/negative) was obtained among the biochemical and hematological parameters (white blood cells (WBC)/ferritin, TF, and hepcidin, mean corpuscular hemoglobin concentration (MCHC)/ferritin and hemopexin) with iron status biomarkers. Finally, receiver operating characteristic (ROC) analysis revealed that hemopexin was significantly associated with greater specificity and sensitivity in discriminating TBL+Ss+ and TBL+Ss- coinfected individuals. Thus, our data conclude that Ss coinfection is associated with altered iron status biomarkers indicating that coinfection might alter the host-Mtb interface and could influence the disease pathogenesis.

Enhanced Severe Acute Respiratory Syndrome Coronavirus 2 Antigen-Specific Systemic Immune Responses in Multisystem Inflammatory Syndrome in Children and Reversal After Recovery.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) presents with inflammation and pathology of multiple organs in the pediatric population in the weeks following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: We characterized the SARS-CoV-2 antigen-specific cytokine and chemokine responses in children with MIS-C, coronavirus disease 2019 (COVID-19), and other infectious diseases. RESULTS: MIS-C is characterized by elevated levels of type 1 (interferon-γ, interleukin [IL] 2), type 2 (IL-4, IL-13), type 17 (IL-17), and other proinflammatory cytokines (IL-1α, IL-6, IL-12p70, IL-18, and granulocyte-macrophage colony-stimulating factor) in comparison to COVID-19 and other infectious diseases following stimulation with SARS-CoV-2-specific antigens. Similarly, upon SARS-CoV-2 antigen stimulation, CCL2, CCL3, and CXCL10 chemokines were significantly elevated in children with MIS-C in comparison to the other 2 groups. Principal component analysis based on these cytokines and chemokines could clearly distinguish MIS-C from both COVID-19 and other infections. In addition, these responses were significantly diminished and normalized 6-9 months after recovery. CONCLUSIONS: Our data suggest that MIS-C is characterized by an enhanced production of cytokines and chemokines that may be associated with disease pathogenesis.

Dominant expansion of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines in culture-positive lymph node tuberculosis.

Lymph node culture-positive tuberculosis (LNTB+) is associated with increased mycobacterial antigen-induced pro-inflammatory cytokine production compared to LN culture-negative tuberculosis (LNTB-). However, the frequencies of CD4+, CD8+ T cells and NK cells expressing Th1/Tc1/Type 1 (IFNγ, TNFα, IL-2), Th17/Tc17/Type 17 (IL-17A, IL-17F, IL-22) cytokines and cytotoxic (perforin [PFN], granzyme [GZE] B, CD107a) markers in LNTB+ and LNTB- individuals are not known. Thus, we have studied the unstimulated (UNS) and mycobacterial antigen-induced frequencies of CD4+, CD8+ T and NK cells expressing Th1, Th17 cytokines and cytotoxic markers using flow cytometry. The frequencies of CD4+, CD8+ T and NK cells expressing cytokines and cytotoxic markers were not significantly different between LNTB+ and LNTB- individuals in UNS condition. In contrast, upon Mtb antigen stimulation, LNTB+ individuals are associated with significantly increased frequencies of CD4+ T cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [IFNγ, TNFα, IL-2]), CD8+ T cells (PPD [IFNγ], ESAT-6 PP [IFNγ], CFP-10 PP [TNFα]) and NK cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [TNFα]) expressing Th1/Tc1/Type 1, but not Th17/Tc17/Type 17 cytokines and cytotoxic markers compared to LNTB- individuals. LNTB+ individuals did not show any significant alterations in the frequencies of CD4+, CD8+ T cells and NK cells expressing cytokines and cytotoxic markers compared to LNTB- individuals upon HIV Gag PP and P/I antigen stimulation. Increased frequencies of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines among the LNTB+ group indicates that the presence of mycobacteria plays a dominant role in the activation of key correlates of immune protection or induces higher immunopathology.

Decreased leukocyte exhaustion is associated with decreased IFN-ß and increased α-defensin-1 levels in type-2 diabetes.

Pan-leukocyte exhaustion is a physiological process associated with immune homeostasis. Too much of immune exhaustion can lead to immune impairment and increased susceptibility to infections and cancer; too little can lead to chronic inflammation. Since type-2 diabetes subjects have both impaired immunity and metainflammation, we looked at TLR induced pan-immune exhaustion and its regulation, in these subjects. TLR induced expression of PD-1 and CTLA-4 in T cells, B cells, monocytes and neutrophils, in whole blood cultures, were quantified by flowcytometry. Circulating levels and in vitro secretion of IFN-ß and α-Defensin-1 (α-DEF-1) were quantified by ELISA. TLR induced expression of PU.1, IRF-3,-4 and -5 in whole blood cultures was quantified by qRT-PCR. Systemic lipid and protein peroxidation was quantified by spectrophotometry. TLR induced expression of PD-1 (in monocytes) and CTLA-4 expression (in B cells and neutrophils) were decreased in drug naive newly diagnosed diabetes patients. This was associated with decreased secretion and circulating levels of IFN-ß and increased secretion and circulating levels of α-DEF-1 in these subjects. No major derangement in the transcriptional network was seen. Many of these defects were only partially rectified in those under treatment. Together, we hypothesize that the high defensin levels could inhibit TLR signalling leading to reduced IFN-ß levels, which in turn could lead to reduced expression of PD-1 and CTLA-4 in the immune cells. This effect along with systemic redox stress could fuel metainflammation in type-2 diabetes.

Baseline IL-6 is a biomarker for unfavourable tuberculosis treatment outcomes: a multisite discovery and validation study.

BACKGROUND: Biomarkers of unfavourable tuberculosis (TB) treatment outcomes are needed to accelerate new drug and regimen development. Whether plasma cytokine levels can predict unfavourable TB treatment outcomes is unclear. METHODS: We identified and internally validated the association between 20 a priori selected plasma inflammatory markers and unfavourable treatment outcomes of failure, recurrence and all-cause mortality among adults with drug-sensitive pulmonary TB in India. We externally validated these findings in two independent cohorts of predominantly diabetic and HIV co-infected TB patients in India and South Africa, respectively. RESULTS: Pre-treatment interferon-γ, interleukin (IL)-13 and IL-6 were associated with treatment failure in the discovery analysis. Internal validation confirmed higher pre-treatment IL-6 concentrations among failure cases compared with controls. External validation among predominantly diabetic TB patients found an association between pre-treatment IL-6 concentrations and subsequent recurrence and death. Similarly, external validation among predominantly HIV co-infected TB patients found an association between pre-treatment IL-6 concentrations and subsequent treatment failure and death. In a pooled analysis of 363 TB cases from the Indian and South African validation cohorts, high pre-treatment IL-6 concentrations were associated with higher risk of failure (adjusted OR (aOR) 2.16, 95% CI 1.08-4.33; p=0.02), recurrence (aOR 5.36, 95% CI 2.48-11.57; p<0.001) and death (aOR 4.62, 95% CI 1.95-10.95; p<0.001). Adding baseline IL-6 to a risk prediction model comprised of low body mass index, high smear grade and cavitation improved model performance by 15% (C-statistic 0.66 versus 0.76; p=0.02). CONCLUSIONS: Pre-treatment IL-6 is a biomarker for unfavourable TB treatment outcomes. Future studies should identify optimal IL-6 concentrations for point-of-care risk prediction.

Recovery of Memory B-cell Subsets and Persistence of Antibodies in Convalescent COVID-19 Patients.

It is essential to examine the longevity of the defensive immune response engendered by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. We examined the SARS-CoV-2-specific antibody responses and ex vivo memory B-cell subsets in seven groups of individuals with COVID-19 classified based on days since reverse-transcription polymerase chain reaction confirmation of SARS-CoV-2 infection. Our data showed that the levels of IgG and neutralizing antibodies started increasing from days 15 to 30 to days 61 to 90, and plateaued thereafter. The frequencies of naive B cells and atypical memory B cells decreased from days 15 to 30 to days 61 to 90, and plateaued thereafter. In contrast, the frequencies of immature B cells, classical memory B cells, activated memory B cells, and plasma cells increased from days 15 to 30 to days 61 to 90, and plateaued thereafter. Patients with severe COVID-19 exhibited increased frequencies of naive cells, atypical memory B cells, and activated memory B cells, and lower frequencies of immature B cells, central memory B cells, and plasma cells when compared with patients with mild COVID-19. Therefore, our data suggest modifications in memory B-cell subset frequencies and persistence of humoral immunity in convalescent individuals with COVID-19.

Impact of HIV status on systemic inflammation during pregnancy.

OBJECTIVE: There are limited studies on the association of HIV infection with systemic inflammation during pregnancy. DESIGN: A cohort study (N = 220) of pregnant women with HIV (N = 70) (all on antiretroviral therapy) and without HIV (N = 150) were enrolled from an antenatal clinic in Pune, India. METHODS: The following systemic inflammatory markers were measured in plasma samples using immunoassays: soluble CD163 (sCD163), soluble CD14 (sCD14), intestinal fatty acid-binding protein (I-FABP), C-reactive protein (CRP), alpha 1-acid glycoprotein (AGP), interferon-ß (IFNß), interferon-γ (IFNγ), interleukin (IL)-1ß, IL-6, IL-13, IL-17A, and tumor necrosis factor α (TNFα). Generalized estimating equation (GEE) and linear regression models were used to assess the association of HIV status with each inflammatory marker during pregnancy and by trimester, respectively. RESULTS: Pregnant women with HIV had higher levels of markers for gut barrier dysfunction (I-FABP), monocyte activation (sCD14) and markers of systemic inflammation (IL-6 and TNFα), but surprisingly lower levels of AGP, an acute phase protein, compared with pregnant women without HIV, with some trimester-specific differences. CONCLUSION: Our data show that women with HIV had higher levels of markers of gut barrier dysfunction, monocyte activation and systemic inflammation. These markers, some of which are associated with preterm birth, might help explain the increase in adverse birth outcomes in women with HIV and could suggest targets for potential interventions.

Discovery and Validation of a Three-Cytokine Plasma Signature as a Biomarker for Diagnosis of Pediatric Tuberculosis.

Pediatric TB poses challenge in diagnosis due to the paucibacillary nature of the disease. We conducted a prospective diagnostic study to identify immune biomarkers of pediatric TB and controls (discovery cohort) and obtained a separate "validation" cohort of confirmed cases of pediatric TB and controls. Multiplex ELISA was performed to examine the plasma levels of cytokines. Discovery and validation cohorts revealed that baseline plasma levels of IFNγ, TNFα, IL-2, and IL-17A were significantly higher in active TB (confirmed TB and unconfirmed TB) in comparison to unlikely TB children. Receiver operating characteristics (ROC) curve analysis revealed that IFNγ, IL-2, TNFα, and IL-17A (in the discovery cohort) and TNFα and IL-17A (in the validation cohort) could act as biomarkers distinguishing confirmed or unconfirmed TB from unlikely TB with the sensitivity and specificity of more than 90%. In the discovery cohort, cytokines levels were significantly diminished following anti-tuberculosis treatment. In both the cohorts, combiROC models offered 100% sensitivity and 98% to 100% specificity for a three-cytokine signature of TNFα, IL-2, and IL-17A, which can distinguish confirmed or unconfirmed TB children from unlikely TB. Thus, a baseline cytokine signature of TNFα, IL-2, and IL-17A could serve as an accurate biomarker for the diagnosis of pediatric tuberculosis.

Diminished Circulating Levels of Angiogenic Factors and Rage Ligands in Helminth-Diabetes Comorbidity and Reversal Following Anthelmintic Treatment.

BACKGROUND: Various epidemiological and experimental studies propose that helminths could play a preventive role against the progression of type 2 diabetes mellitus (T2DM). T2DM induces microvascular and large vessel complications mediated by elevated levels of angiogenic factors and soluble receptor for advanced glycation end product (RAGE) ligands. However, the interactions between helminths and host angiogenic factors and RAGE ligands are unexplored. METHODS: To assess the relationship between a soil-transmitted helminth, Strongyloides stercoralis (Ss), and T2DM, we measured plasma levels of vascular endothelial growth factor (VEGF)-A, -C, and -D; angiopoietins 1 and 2 (Ang-1 and Ang-2); and their receptors VEGF-R1, -R2, and -R3 as well as soluble RAGE (sRAGE) and their ligands advanced glycation end products (AGEs), S100A12, and high mobility group box 1 (HMGB-1) in individuals with T2DM with or those without Ss infection. In Ss-infected individuals, we also measured the levels of aforementioned factors 6 months following anthelmintic therapy. RESULTS: Ss-infected individuals exhibited significantly decreased levels of VEGF-A, VEGF-C, VEGF-D, Ang-1, and Ang-2 and their soluble receptors VEGF-R1, -R2, and -R3, that increased following anthelmintic therapy. Likewise, Ss-infected individuals exhibited significantly decreased levels of AGEs and their ligands sRAGE, S100A12, and HMGB-1, which reversed following anthelmintic therapy. CONCLUSIONS: Our data suggest that Ss infection could play a beneficial role by limiting or delaying T2DM-related vascular complications.

Diminished Frequencies of Cytotoxic Marker Expressing T- and NK Cells at the Site of Mycobacterium tuberculosis Infection.

Tuberculous lymphadenitis (TBL) individuals exhibit reduced frequencies of CD8+ T cells expressing cytotoxic markers in peripheral blood. However, the frequencies of cytotoxic marker expressing CD4+, CD8+ T cells, and NK cells at the site of infection is not known. Therefore, we measured the baseline and mycobacterial antigen specific frequencies of cytotoxic markers expressing CD4+, CD8+ T cells, and NK cells in the LN (n = 18) and whole blood (n = 10) of TBL individuals. TBL LN is associated with lower frequencies of CD4+ T cells expressing cytotoxic markers (Granzyme B, CD107a) compared to peripheral blood at baseline and in response to PPD, ESAT-6, and CFP-10 antigen stimulation. Similarly, lower frequencies of CD8+ T cells expressing cytotoxic markers (Perforin, Granzyme B, and CD107a) were also present in the TBL LN at baseline and following (except perforin) antigen stimulation. Finally, at baseline and after antigen (PPD, ESAT-6, and CFP-10) stimulation, frequencies of NK cells expressing cytotoxic markers were also significantly lower in TBL LN compared to whole blood. Hence, TBL is characterized by diminished frequencies of cytotoxic marker expressing CD4+, CD8+ T cells, and NK cells at the site of infection, which might reflect the lack of protective immune responses at the site of Mycobacterium tuberculosis infection.

Low body mass index has minimal impact on plasma levels of cytokines and chemokines in tuberculous lymphadenitis.

Malnutrition, due to low body mass index (LBMI), is considered to be one of the key risk factors for tuberculosis (TB) development. The link between pro and anti-inflammatory cytokines and BMI has been studied in active pulmonary TB. However, the association of BMI with cytokines and chemokines in TB lymphadenitis (TBL) has not been examined. Hence, we wanted to examine the plasma levels of different cytokines and chemokines in TBL individuals with LBMI, normal BMI (NBMI) and high BMI (HBMI). LBMI with TBL disease is associated with enhanced systemic levels of type 1 (tumor necrosis factor alpha [TNFα], interleukin-2 [IL-2]) and type 2 (IL-4, IL-13) cytokines in comparison with NBMI and/or HBMI. However, other pro-inflammatory (IFNγ, IL-1ß, IL-17A, IL-6, IL-7, IL-12, G-CSF, and GM-CSF) and anti-inflammatory (IL-5 and IL-10) cytokines were not significantly different among the TBL individuals with different BMI status. Likewise, no significant differences were observed in the CC (CCL-1, CCL-2/MCP-1, CCL3/MIP1α, CCL4/MIP-1ß, CCL11/eotaxin) and CXC (CXCL-1/GRO-⍺, CXCL2/GRO-ß, CXCL9/MIG, CXCL10/IP-10, CXCL11/ITAC 1) chemokine profile among the TBL individuals with different BMI. Hence, our data implies that TBL individuals with LBMI are characterized by minimal effects on plasma cytokines and chemokines in TBL.

Heterogeneity in the cytokine profile of tuberculosis - diabetes co-morbidity.

Tuberculosis - diabetes (TB-DM) co-morbidity is characterized by heterogeneity in clinical and biochemical parameters between newly diagnosed diabetic individuals with TB (TB-NDM) and known diabetic individuals at incident TB (TB-KDM). However, the immunological profile underlying this heterogeneity is not explored. To identify the cytokine profiles in TB-NDM and TB-KDM individuals, we examined the plasma cytokine levels as well as TB-antigen stimulated levels of pro-inflammatory cytokines. TB-KDM individuals exhibit significantly higher levels of IFNγ, IL-2, TNFα, IL-17A, IL-1α, IL-1ß and IL-6 in comparison to TB-NDM, TB alone and DM alone individuals. TB-NDM individuals are characterized by significantly lower levels of blood glucose and glycated hemoglobin in comparison to TB-KDM with both groups exhibiting a significant lowering of glycated hemoglobin levels at 6  months of anti-tuberculosis therapy (ATT). TB-NDM individuals are characterized by significantly diminished - unstimulated levels of IFNγ, IL-2, TNFα, IL-17A, IL-1α, IL-1ß and IL-12 at pre-treatment, of IFNγ, IL-2 and IL-1α at 2  months of ATT and IL-2 at post-treatment in comparison to TB-KDM. TB-NDM individuals are also characterized by significantly diminished TB-antigen stimulated levels of IFNγ, IL-2, TNFα, IL-17A, IL-17F, IL-1α, IL-1ß and/or IL-6 at pre-treatment and at 2  months of ATT and IFNγ, IL-2, IL-1α and IL-1ß at post-treatment. In addition, TB-NDM individuals are characterized by significantly diminished mitogen - stimulated levels of IL-17F and IL-6 at pre-treatment and IL-6 alone at 6 months of ATT. Therefore, our data reveal considerable heterogeneity in the immunological underpinnings of TB-DM co-morbidity. Our data also suggest that TB-NDM exhibits a characteristic profile, which is both biochemically and immunologically distinct from TB-KDM.

Systemic RAGE ligands are upregulated in tuberculosis individuals with diabetes co-morbidity and modulated by anti-tuberculosis treatment and metformin therapy.

BACKGROUND: Ligands of the receptor for advanced glycation end products (RAGE) are key signalling molecules in the innate immune system but their role in tuberculosis-diabetes comorbidity (TB-DM) has not been investigated. METHODS: We examined the systemic levels of soluble RAGE (sRAGE), advanced glycation end products (AGE), S100A12 and high mobility group box 1 (HMGB1) in participants with either TB-DM, TB, DM or healthy controls (HC). RESULTS: Systemic levels of AGE, sRAGE and S100A12 were significantly elevated in TB-DM and DM in comparison to TB and HC. During follow up, AGE, sRAGE and S100A12 remained significantly elevated in TB-DM compared to TB at 2nd month and 6th month of anti-TB treatment (ATT). RAGE ligands were increased in TB-DM individuals with bilateral and cavitary disease. sRAGE and S100A12 correlated with glycated hemoglobin levels. Within the TB-DM group, those with known diabetes (KDM) revealed significantly increased levels of AGE and sRAGE compared to newly diagnosed DM (NDM). KDM participants on metformin treatment exhibited significantly diminished levels of AGE and sRAGE in comparison to those on non-metformin regimens. CONCLUSIONS: Our data demonstrate that RAGE ligand levels reflect disease severity and extent in TB-DM, distinguish KDM from NDM and are modulated by metformin therapy.

Plasma Eicosanoid Levels in Tuberculosis and Tuberculosis-Diabetes Co-morbidity Are Associated With Lung Pathology and Bacterial Burden.

Host eicosanoids are lipid mediators of inflammation that are commonly accepted as important modulators of the host immune response in Mycobacterium tuberculosis infection. During active tuberculosis (TB), eicosanoids may play an important role in the regulation of inflammatory responses. However, a detailed investigation of the relationship of eicosanoids in TB and TB-diabetes comorbidity (TB-DM) and association to disease pathology or bacterial burdens has not been studied. To study this, we examined the plasma levels of Lipoxin A4 (LXA4), 15-epi-LXA4, Leukotriene B4 (LTB4), and Prostaglandin E2 (PGE2) in individuals with either TB-DM, TB, diabetes mellitus (DM) or healthy controls (HC). Plasma levels of LXA4, 15-epi-LXA4, and PGE2 were significantly increased while the levels of LTB4 were significantly decreased in TB-DM and TB group compared to DM and HC. The ratio of LXA4 to LTB4 and 15-epiLXA4 to LTB4 was significantly enhanced in TB-DM compared to TB. Moreover, the levels of LXA4, 15-epi-LXA4 and the ratios of LXA4 to LTB4 and 15-epiLX4 to LTB4 were significantly increased in TB individuals with bilateral or cavitary disease and these markers also revealed a significant positive relationship with bacterial burden. At the completion of anti-tuberculosis therapy (ATT), levels of LXA4, 15-epi-LXA4, and PGE2 in TB-DM and TB groups were diminished and levels of LTB4 were enhanced in the TB group compared to pre-treatment. Our data imply that alteration and upregulation of eicosanoids are standard characteristics of TB-DM co-morbidity. Our data also demonstrate that modulation in the eicosanoid levels reflect disease severity and extent in TB and TB-DM and are modulated by ATT.

Diminished type 1 and type 17 cytokine expressing - Natural killer cell frequencies in tuberculous lymphadenitis.

Tuberculous lymphadenitis (TBL) is associated with the expansion of CD4+ and CD8+ T cells expressing Type 1 and Type 17 cytokines in the peripheral blood. However, the expression pattern of cytokine producing natural killer (NK) cells in both the peripheral blood and affected lymph nodes i.e. site of infection in TBL have not been examined. Hence, we have analyzed the baseline and mycobacterial antigen specific NK cell cytokine frequencies in whole blood of TBL and pulmonary tuberculosis (PTB) individuals. We have also examined the NK cell frequencies before and after treatment completion and in peripheral blood versus affected lymph nodes (LN) of TBL individuals. TBL is characterized by diminished frequencies of NK cells expressing Type 1 (IFNγ, TNFα), Type 17 (IL-17F) cytokines compared to PTB individuals upon antigen-specific stimulation. In contrast, TBL individuals did not exhibit any significant differences in the frequencies of NK cells expressing Type 1 and Type 17 cytokines upon completion of anti-tuberculosis treatment. LN of TBL is associated with altered frequencies of NK cells expressing Type 17 (increased IL-17F and decreased IL-22) cytokines when compared to peripheral blood. Thus, we conclude that TBL individuals are characterized by diminished frequencies of NK cells expressing Type 1/Type 17 cytokines.

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.

Molecular degree of perturbation of plasma inflammatory markers associated with tuberculosis reveals distinct disease profiles between Indian and Chinese populations.

Tuberculosis (TB) is a chronic inflammatory disease caused by Mycobacterium tuberculosis infection which causes tremendous morbidity and mortality worldwide. Clinical presentation of TB patients is very diverse and disease heterogeneity is associated with changes in biomarker signatures. Here, we compared at the molecular level the extent of individual inflammatory perturbation of plasma protein and lipid mediators associated with TB in patients in China versus India. We performed a cross-sectional study analyzing the overall degree of inflammatory perturbation in treatment-naïve pulmonary TB patients and uninfected individuals from India (TB: n = 97, healthy: n = 20) and China (TB: n = 100, healthy: n = 11). We employed the molecular degree of perturbation (MDP) adapted to plasma biomarkers to examine the overall changes in inflammation between these countries. M. tuberculosis infection caused a significant degree of molecular perturbation in patients from both countries, with higher perturbation detected in India. Interestingly, there were differences in biomarker perturbation patterns and the overall degree of inflammation. Patients with severe TB exhibited increased MDP values and Indian patients with this condition exhibited even higher degree of perturbation compared to Chinese patients. Network analyses identified IFN-α, IFN-ß, IL-1RI and TNF-α as combined biomarkers that account for the overall molecular perturbation in the entire study population. Our results delineate the magnitude of the systemic inflammatory perturbation in pulmonary TB and reveal qualitative changes in inflammatory profiles between two countries with high disease prevalence.