Role of tumour necrosis factor (TNF) in host defence against tuberculosis: implications for immunotherapies targeting TNF

The Cyclooxygenase 2 Inhibitor Etoricoxib as Adjunctive Therapy in Tuberculosis Impairs Macrophage Control of Mycobacterial Growth

BACKGROUND

Current tuberculosis treatment regimens could be improved by adjunct host-directed therapies (HDT) targeting host responses. We investigated the antimycobacterial capacity of macrophages from patients with tuberculosis in a phase 1/2 randomized clinical trial (TBCOX2) of the cyclooxygenase-2 inhibitor etoricoxib.

METHODS

Peripheral blood mononuclear cells from 15 patients with tuberculosis treated with adjunctive COX-2i and 18 controls (standard therapy) were collected on day 56 after treatment initiation. The ex vivo capacity of macrophages to control mycobacterial infection was assessed by challenge with Mycobacterium avium, using an in vitro culture model. Macrophage inflammatory responses were analyzed by gene expression signatures, and concentrations of cytokines were analyzed in supernatants by multiplex.

RESULTS

Macrophages from patients receiving adjunctive COX-2i treatment had higher M. avium loads than controls after 6 days, suggesting an impaired capacity to control mycobacterial infection compared to macrophages from the control group. Macrophages from the COX-2i group had lower gene expression of TNF, IL-1B, CCL4, CXCL9, and CXCL10 and lowered production of cytokines IFN-β and S100A8/A9 than controls.

CONCLUSIONS

Our data suggest potential unfavorable effects with impaired macrophage capacity to control mycobacterial growth in patients with tuberculosis receiving COX-2i treatment. Larger clinical trials are required to analyze the safety of COX-2i as HDT in patients with tuberculosis.

CLINICAL TRIALS REGISTRATION

NCT02503839.

Correlation of Increased Soluble Tumor Necrosis Factor Receptor 1 with Mortality and Dependence on Treatment in Non-Small-Cell Lung Cancer Patients: A Longitudinal Cohort Study

BACKGROUND

Tumor necrosis factor (TNF) is a multipotent cytokine involved in inflammation and anti-tumor activity. TNF-α exerts its function upon binding to TNF-receptor 1 (TNF-R1) and TNF-receptor 2 (TNF-R2). This study investigates the relationship of soluble (s) TNF-R1 levels in non-small-cell lung cancer (NSCLC) patients with treatment and overall survival.

METHODS

In total, 134 NSCLC patients treated at the Medical Faculty of Martin Luther University Halle-Wittenberg between 2017 and 2019 were included in this study. Serum levels of sTNF-R1 were measured via ELISA at baseline and during and after treatment. A linear mixed-effects model was used to assess sTNF-R1 changes over time. Linear regression was applied to investigate the association between clinical characteristics and changes in sTNF-R1. Cox regression models were used to estimate associations with overall mortality.

RESULTS

The estimated average sTNFR-1 at baseline was 2091.71 pg/mL, with a change of 6.19 pg/mL per day. Cox models revealed that the individual change in sTNF-R1 was more strongly associated with mortality than its baseline value, especially after adjusting for covariates.

CONCLUSIONS

This study provides evidence that the individual change in sTNF-R1 levels during and after treatment were associated with the risk of mortality, suggesting the use of the sTNF-R1 trajectory as a prognostic marker.

TNFα aggravates detrimental effects of SARS-CoV-2 infection in the liver

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This virus does not only lead to pulmonary infection but can also infect other organs such as the gut, the kidney, or the liver. Recent studies confirmed that severe cases of COVID-19 are often associated with liver damage and liver failure, as well as the systemic upregulation of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNFα). However, the impact these immune mediators in the liver have on patient survival during SARS-CoV-2 infection is currently unknown. Here, by performing a post-mortem analysis of 45 patients that died from a SARS-CoV-2 infection, we find that an increased expression of TNFA in the liver is associated with elevated mortality. Using publicly available single-cell sequencing datasets, we determined that Kupffer cells and monocytes are the main sources of this TNFα production. Further analysis revealed that TNFα signaling led to the upregulation of pro-inflammatory genes that are associated with an unfavorable outcome. Moreover, high levels of TNFA in the liver were associated with lower levels of interferon alpha and interferon beta. Thus, TNFα signaling in the infected SARS-CoV-2 liver correlates with reduced interferon levels and overall survival time.

HIV/Mtb Co-Infection: From the Amplification of Disease Pathogenesis to an “Emerging Syndemic”

Human immunodeficiency virus (HIV) and Mycobacterium tuberculosis (Mtb) are pathogens responsible for millions of new infections each year; together, they cause high morbidity and mortality worldwide. In addition, late-stage HIV infection increases the risk of developing tuberculosis (TB) by a factor of 20 in latently infected people, and even patients with controlled HIV infection on antiretroviral therapy (ART) have a fourfold increased risk of developing TB. Conversely, Mtb infection exacerbates HIV pathogenesis and increases the rate of AIDS progression. In this review, we discuss this reciprocal amplification of HIV/Mtb coinfection and how they influence each other’s pathogenesis. Elucidating the infectious cofactors that impact on pathogenesis may open doors for the design of new potential therapeutic strategies to control disease progression, especially in contexts where vaccines or the sterile clearance of pathogens are not effectively available.

Beyond the Clinic: The Activation of Diverse Cellular and Humoral Factors Shapes the Immunological Status of Patients with Active Tuberculosis

Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis (TB), has killed nearly one billion people in the last two centuries. Nowadays, TB remains a major global health problem, ranking among the thirteen leading causes of death worldwide. Human TB infection spans different levels of stages: incipient, subclinical, latent and active TB, all of them with varying symptoms, microbiological characteristics, immune responses and pathologies profiles. After infection, Mtb interacts with diverse cells of both innate and adaptive immune compartments, playing a crucial role in the modulation and development of the pathology. Underlying TB clinical manifestations, individual immunological profiles can be identified in patients with active TB according to the strength of their immune responses to Mtb infection, defining diverse endotypes. Those different endotypes are regulated by a complex interaction of the patient's cellular metabolism, genetic background, epigenetics, and gene transcriptional regulation. Here, we review immunological categorizations of TB patients based on the activation of different cellular populations (both myeloid and lymphocytic subsets) and humoral mediators (such as cytokines and lipid mediators). The analysis of the participating factors that operate during active Mtb infection shaping the immunological status or immune endotypes of TB patients could contribute to the development of Host Directed Therapy.

Rheumatoid arthritis caused by non-tuberculous mycobacteria infection

A 72-year-old Japanese woman had right digital flexor tenosynovitis with a non-tuberculous mycobacteria (NTM) infection, which was identified as Mycobacterium marinum in culture. She had been treated at another hospital with clarithromycin, rifampicin, and ethambutol for the non-tuberculous tenosynovitis. However, the swelling of her right hand worsened, and 5 months later, her left hand swelled and she exhibited symmetrical arthritis. Blood tests detected elevated serum C-reactive protein and rheumatoid factor positivity. Although rheumatoid arthritis (RA) was suspected and corticosteroid treatment was started, she came to our hospital because of the insufficient treatment effect. Musculoskeletal ultrasonography showed intra-articular and peritendinous power Doppler signal-positive symmetrical synovitis. A contrast-enhanced magnetic resonance imaging (MRI) evaluation of the left hand without NTM tenosynovitis revealed findings of inflammatory synovitis accompanied by bone marrow oedema. We diagnosed RA and started treatment with weekly low-dose methotrexate pulses and 2 weeks of tocilizumab administration; her symptoms then disappeared within 2 months. This is a rare case of RA manifested with NTM-associated arthritis.

In-depth systems biological evaluation of bovine alveolar macrophages suggests novel insights into molecular mechanisms underlying Mycobacterium bovis infection

OBJECTIVE

Bovine tuberculosis (bTB) is a chronic respiratory infectious disease of domestic livestock caused by intracellular Mycobacterium bovis infection, which causes ~$3 billion in annual losses to global agriculture. Providing novel tools for bTB managements requires a comprehensive understanding of the molecular regulatory mechanisms underlying the M. bovis infection. Nevertheless, a combination of different bioinformatics and systems biology methods was used in this study in order to clearly understand the molecular regulatory mechanisms of bTB, especially the immunomodulatory mechanisms of M. bovis infection.

METHODS

RNA-seq data were retrieved and processed from 78 (39 non-infected control vs. 39 M. bovis-infected samples) bovine alveolar macrophages (bAMs). Next, weighted gene co-expression network analysis (WGCNA) was performed to identify the co-expression modules in non-infected control bAMs as reference set. The WGCNA module preservation approach was then used to identify non-preserved modules between non-infected controls and M. bovis-infected samples (test set). Additionally, functional enrichment analysis was used to investigate the biological behavior of the non-preserved modules and to identify bTB-specific non-preserved modules. Co-expressed hub genes were identified based on module membership (MM) criteria of WGCNA in the non-preserved modules and then integrated with protein-protein interaction (PPI) networks to identify co-expressed hub genes/transcription factors (TFs) with the highest maximal clique centrality (MCC) score (hub-central genes).

RESULTS

As result, WGCNA analysis led to the identification of 21 modules in the non-infected control bAMs (reference set), among which the topological properties of 14 modules were altered in the M. bovis-infected bAMs (test set). Interestingly, 7 of the 14 non-preserved modules were directly related to the molecular mechanisms underlying the host immune response, immunosuppressive mechanisms of M. bovis, and bTB development. Moreover, among the co-expressed hub genes and TFs of the bTB-specific non-preserved modules, 260 genes/TFs had double centrality in both co-expression and PPI networks and played a crucial role in bAMs-M. bovis interactions. Some of these hub-central genes/TFs, including PSMC4, SRC, BCL2L1, VPS11, MDM2, IRF1, CDKN1A, NLRP3, TLR2, MMP9, ZAP70, LCK, TNF, CCL4, MMP1, CTLA4, ITK, IL6, IL1A, IL1B, CCL20, CD3E, NFKB1, EDN1, STAT1, TIMP1, PTGS2, TNFAIP3, BIRC3, MAPK8, VEGFA, VPS18, ICAM1, TBK1, CTSS, IL10, ACAA1, VPS33B, and HIF1A, had potential targets for inducing immunomodulatory mechanisms by M. bovis to evade the host defense response.

CONCLUSION

The present study provides an in-depth insight into the molecular regulatory mechanisms behind M. bovis infection through biological investigation of the candidate non-preserved modules directly related to bTB development. Furthermore, several hub-central genes/TFs were identified that were significant in determining the fate of M. bovis infection and could be promising targets for developing novel anti-bTB therapies and diagnosis strategies.

Therapeutic Utility and Adverse Effects of Biologic Disease-Modifying Anti-Rheumatic Drugs in Inflammatory Arthritis

Targeting specific pathologic pro-inflammatory cytokines or related molecules leads to excellent therapeutic effects in inflammatory arthritis, including rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis. Most of these agents, known as biologic disease-modifying anti-rheumatic drugs (bDMARDs), are produced in live cell lines and are usually monoclonal antibodies. Several types of monoclonal antibodies target different pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-17A, IL-6, and IL-23/12. Some bDMARDs, such as rituximab and abatacept, target specific cell-surface molecules to control the inflammatory response. The therapeutic effects of these bDMARDs differ in different forms of inflammatory arthritis and are associated with different adverse events. In this article, we summarize the therapeutic utility and adverse effects of bDMARDs and suggest future research directions for developing bDMARDs.

Uncovering a Hub Signaling Pathway of Antimicrobial-Antifungal-Anticancer Peptides’ Axis on Short Cationic Peptides via Network Pharmacology Study

Short cationic peptides (SCPs) with therapeutic efficacy of antimicrobial peptides (AMPs), antifungal peptides (AFPs), and anticancer peptides (ACPs) are known as an enhancement of the host defense system. Here, we investigated the uppermost peptide(s), hub signaling pathway(s), and their associated target(s) through network pharmacology. Firstly, we selected SCPs with positive amino acid residues on N- and C- terminals under 500 Dalton via RStudio. Secondly, the overlapping targets between the bacteria-responsive targets (TTD and OMIM) and AMPs’ targets were visualized by VENNY 2.1. Thirdly, the overlapping targets between AFPs’ targets and fungal-responsive targets were exhibited by VENNY 2.1. Fourthly, the overlapping targets between cancer-related targets (TTD and OMIM) and fungal-responsive targets were displayed by VENNY 2.1. Finally, a molecular docking study (MDS) was carried out to discover the most potent peptides on a hub signaling pathway. A total of 1833 SCPs were identified, and AMPs’, AFPs’, and ACPs’ filtration suggested that 197 peptides (30 targets), 81 peptides (6 targets), and 59 peptides (4 targets) were connected, respectively. The AMPs―AFPs―ACPs’ axis indicated that 27 peptides (2 targets) were associated. Each hub signaling pathway for the enhancement of the host defense system was “Inactivation of Rap1 signaling pathway on AMPs”, “Activation of Notch signaling pathway on AMPs―AFPs’ axis”, and “Inactivation of HIF-1 signaling pathway on AMPs―AFPs―ACPs’ axis”. The most potent peptides were assessed via MDS; finally, HPIK on STAT3 and HVTK on NOS2 and on HIF-1 signaling pathway were the most stable complexes. Furthermore, the two peptides had better affinity scores than standard inhibitors (Stattic, 1400 W). Overall, the most potent SCPs for the human defense system were HPIK on STAT3 and HVTK on NOS2, which might inactivate the HIF-1 signaling pathway.

TNF-α impairs EP4 signaling through the association of TRAF2-GRK2 in primary fibroblast-like synoviocytes

Our previous study showed that chronic treatment with tumor necrosis factor-α (TNF-α) decreased cAMP concentration in fibroblast-like synoviocytes (FLSs) of collagen-induced arthritis (CIA) rats. In this study we investigated how TNF-α impairs cAMP homeostasis, particularly clarifying the potential downstream molecules of TNF-α and prostaglandin receptor 4 (EP4) signaling that would interact with each other. Using a cAMP FRET biosensor PM-ICUE3, we demonstrated that TNF-α (20 ng/mL) blocked ONO-4819-triggered EP4 signaling, but not Butaprost-triggered EP2 signaling in normal rat FLSs. We showed that TNF-α (0.02-20 ng/mL) dose-dependently reduced EP4 membrane distribution in normal rat FLS. TNF-α significantly increased TNF receptor 2 (TNFR2) expression and stimulated proliferation in human FLS (hFLS) via ecruiting TNF receptor-associated factor 2 (TRAF2) to cell membrane. More interestingly, we revealed that TRAF2 interacted with G protein-coupled receptor kinase (GRK2) in the cytoplasm of primary hFLS and helped to bring GRK2 to cell membrane in response of TNF-α stimulation, the complex of TRAF2 and GRK2 then separated on the membrane, and translocated GRK2 induced the desensitization and internalization of EP4, leading to reduced production of intracellular cAMP. Silencing of TRAF2 by siRNA substantially diminished TRAF2-GRK2 interaction, blocked the translocation of GRK2, and resulted in upregulated expression of membrane EP4 and intracellular cAMP. In CIA rats, administration of paroxetine to inhibit GRK2 effectively improved the symptoms and clinic parameters with significantly reduced joint synovium inflammation and bone destruction. These results elucidate a novel form of cross-talk between TNFR (a cytokine receptor) and EP4 (a typical G protein-coupled receptor) signaling pathways. The interaction between TRAF2 and GRK2 may become a potential new drug target for the treatment of inflammatory diseases.

Biological Therapies for Rheumatoid Arthritis: An Overview for the Clinician

Rheumatoid arthritis (RA) is a disease characterised by inflammation of synovial joints and poses a substantial healthcare burden on both the individual and society. One of the most significant shifts in the RA therapeutic landscape has occurred with the introduction of biological disease modifying anti-rheumatic drugs (bDMARDs). There are five classes of bDMARDs currently available, each with a different molecular target and subtle differences in their efficacy and safety profile. This review also describes the “real-world” use of bDMARDs and how they fit into the overall RA treatment guidelines.

IMPACT OF NON-SURGICAL PERIODONTAL TREATMENT ON SERUM TNF-α LEVELS IN INDIVIDUALS WITH TYPE 2 DIABETES: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVE

The objective of this systematic review and meta-analysis was to search for scientific evidence on the impact of non-surgical periodontal therapy on tumor necrosis factor alpha (TNF-α) in type 2 diabetics.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement has been followed. The study was registered (CRD42020192790) in the International prospective register of systematic reviews. Searches were conducted in five databases. Restrictions on publication date were not imposed in anyway. The studies reporting the serum TNF-α levels of individuals with type 2 diabetes mellitus (DM) before and after non-surgical periodontal therapy were included. Studies' selection, extraction of data and risk of bias assessment were performed in duplicate. Consensus was achieved. Meta-analysis was carried out. The 95% confidence interval and odds ratio were provided.

RESULTS

Six hundred and twenty-three references were retrieved and eighteen studies were included. Meta-analysis demonstrated that the serum levels of TNF-α in individuals with type 2 DM decreased six months after non-surgical periodontal therapy (mean difference = -1.90, confidence interval = -3.05--0.74). Included studies presented low risk of bias.

CONCLUSION

Non-surgical periodontal therapy has an impact on serum TNF-α levels at six months in type 2 DM patients.

Interleukins and cytokine biomarkers in uveitis

Interleukins and cytokines are involved in the pathogenesis of uveitis of heterogeneous origin. Understanding the basics of the ocular immune privilege is a fulcrum to discern their specific role in diverse uveitis to potentially translate as therapeutic targets. This review attempts to cover these elements in uveitis of infectious, noninfectious and masquerade origin. Insights of the molecular targets in novel therapy along with the vision of future research are intriguing.

Tuberculosis endotypes to guide stratified host-directed therapy

There is hope that host-directed therapy (HDT) for Tuberculosis (TB) can either shorten treatment duration, help cure drug resistant disease or limit the immunopathology. Many candidate HDT drugs have been proposed, however solid evidence only exists for a few select patient groups. The clinical presentation of TB is variable, with differences in severity, tissue pathology, and bacillary burden. TB clinical phenotypes likely determine the potential benefit of HDT. Underlying TB clinical phenotypes, there are TB "endotypes," defined as distinct molecular profiles, with specific metabolic, epigenetic, transcriptional, and immune phenotypes. TB endotypes can be characterized by either immunodeficiency or pathologic excessive inflammation. Additional factors, like comorbidities (HIV, diabetes, helminth infection), structural lung disease or Mycobacterial virulence also drive TB endotypes. Precise disease phenotyping, combined with in-depth immunologic and molecular profiling and multimodal omics integration, can identify TB endotypes, guide endotype-specific HDT, and improve TB outcomes, similar to advances in cancer medicine.

-308G/A polymorphism of tumor necrosis factor alpha (TNF-α) gene and metabolic syndrome susceptibility: a meta-analysis

Many studies tried to assess the relationship between -308G/A polymorphism of tumor necrosis factor alpha (TNF-α) gene and risk of metabolic syndrome (MS), but their results were contradictory. This meta-analysis aimed to precisely evaluate this association. A systematic literature search was performed in Pubmed database and WanFang Med Online, STATA software 14.0 was used for the meta-analysis. Eleven independent studies containing 3277 cases and 3312 controls were included in our meta-analysis. In overall analysis, significant association was found between -308G/A polymorphism of TNF-α and MS in both allele model (OR 1.47, 95% CI 1.09–1.98, P 0.013) and dominant model (OR 1.77, 95% CI 1.21–2.58, P 0.003). In the subgroup analysis, the A allele was associated with increased risk of MS in Asia group (allele model: OR 1.82 95% CI 1.31–2.53, P < 0.001; dominant model: OR 2.30, 95% CI 1.64–3.21 P < 0.001; homozygous model: OR 2.29, 95% CI 1.31–4.01, P 0.004), and decreased risk of MS in Europe group (dominant model: OR 0.83, 95% CI 0.70–0.99, P < 0.001; recessive model: OR 0.51, 95% CI 0.28–0.92, P 0.025; homozygous model: OR 0.49 95% CI 0.27–0.89, P 0.02). The A allele also appeared to linked to increased risk of MS in CDS group and IDF groups. No significant association was observed in NCEPATPIII group. Our results suggested that -308G/A of TNF-α gene was a risk factor for MS, but it may played different roles in different ethnics, further studies with larger sample size and more other ethnics should be performed to confirm our conclusions.

Perspective for Precision Medicine for Tuberculosis

Tuberculosis is a bacterial infectious disease that is mainly transmitted from human to human via infectious aerosols. Currently, tuberculosis is the leading cause of death by an infectious disease world-wide. In the past decade, the number of patients affected by tuberculosis has increased by ~20 percent and the emergence of drug-resistant strains of Mycobacterium tuberculosis challenges the goal of elimination of tuberculosis in the near future. For the last 50 years, management of patients with tuberculosis has followed a standardized management approach. This standardization neglects the variation in human susceptibility to infection, immune response, the pharmacokinetics of drugs, and the individual duration of treatment needed to achieve relapse-free cure. Here we propose a package of precision medicine-guided therapies that has the prospect to drive clinical management decisions, based on both host immunity and M. tuberculosis strains genetics. Recently, important scientific discoveries and technological advances have been achieved that provide a perspective for individualized rather than standardized management of patients with tuberculosis. For the individual selection of best medicines and host-directed therapies, personalized drug dosing, and treatment durations, physicians treating patients with tuberculosis will be able to rely on these advances in systems biology and to apply them at the bedside.

Tuberculosis and targeted synthetic or biologic DMARDs, beyond tumor necrosis factor inhibitors

Patients with autoimmune rheumatic diseases (ARD) have an increased risk for tuberculosis (TB). The use of tumor necrosis factor inhibitors (TNFi) and glucocorticoids in these patients has been associated with an increased prevalence of latent TB reactivation. Over the last few years, several biologic disease-modifying anti-rheumatic drugs (bDMARDs), other than TNFi (e.g. rituximab, abatacept, tocilizumab, secukinumab) and targeted synthetic DMARDs (tsDMARDs) [e.g. apremilast, Janus kinase (JAK) inhibitors] have been used for the treatment of patients with ARD. For many of these drugs, especially the newer ones like JAK inhibitors or antibodies against interleukin (IL)-23, most data stem from randomized clinical trials and few are available from real life clinical experience. We sought to review the current evidence for TB risk in patients with ARD treated with tsDMARDs or bDMARDs, other than TNFi. It seems that some of these drugs are associated with a lower TB risk, indirectly compared with TNFi treatment. In fact, it appears that rituximab, apremilast and inhibitors of IL-17 and IL-23 might be safer, while more data are needed for JAK inhibitors. As seen in TNFi, risk for TB is more pronounced in TB-endemic areas. Screening for latent TB must precede initiation of any tsDMARDs or bDMARDs. The growing use of non-TNFi agents has raised the need for more real-life studies that would compare the risk for TB between TNFi and other treatment modalities for ARD. Knowledge about the TB-safety profile of these drugs could help in the decision of drug choice in patients with confirmed latent TB infection or in TB endemic areas.

New Insights on the Effect of TNF Alpha Blockade by Gene Silencing in Noise-Induced Hearing Loss

Noise exposure represents the second most common cause of acquired sensorineural hearing loss and we observed that tumor necrosis factor α (TNFα) was involved in this context. The effect of Tnfα gene silencing on the expression profile related to the TNFα metabolic pathway in an experimental model of noise-induced hearing loss had not previously been studied. Methods: Single ears of Wistar rats were pretreated with Tnfα small interfering RNA (siRNA) by trans-tympanic administration 24 h before they were exposed to white noise (120 dBSPL for three hours). After 24 h of noise exposure, we analyzed the electrophysiological threshold and the amplitude of waves I, II, III, and IV in the auditory brain response click. In addition, qRT-PCR was performed to evaluate the TNFα metabolic pathway in the ears submitted or not to gene silencing. Results: Preservation of the electrophysiological threshold and the amplitude of waves was observed in the ears submitted to gene silencing compared to the ears not treated. Increased anti-apoptotic gene expression and decreased pro-apoptotic gene expression were found in the treated ears. Conclusion: Our results allow us to suggest that the blockade of TNFα by gene silencing was useful to prevent noise-induced hearing loss.

A population-based study of tuberculosis incidence among rheumatic disease patients under anti-TNF treatment

Introduction

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. The advent of immunobiologic therapy with TNF inhibitors agents, has been associated with a significant increase in incident cases of tuberculosis in this population.

Objective

To estimate the incidence of tuberculosis in patients receiving TNF inhibitors therapy for rheumatic diseases. As secondary objectives, we sought to evaluate mortality and the clinical impact of screening for latent tuberculosis infection.

Methods

This retrospective study included patients with rheumatic diseases of Public Health System from the Brazilian state, a high TB incidence area, who received prescriptions of TNF inhibitors agents between 2006 and 2016.

Results

A total of 5853 rheumatic disease patients were included. Patients were predominantly women (68.7%) aged 49.5 (± 14.7) years old. Forty-three cases of TB were found (2.86 cases per 1000 person-years; 18 times higher than in the general population). Adalimumab and certolizumab users presented a higher risk for TB development compared to etanercept users (RR: 3.11, 95%CI 1.16–8.35; 7.47, 95%CI 1.39–40.0, respectively). In a subgroup of patients, screening for latent tuberculosis infection was performed in 86% of patients, and 30.2% had a positive tuberculin skin test. Despite latent TB treatment, TB was diagnosed in 2 out of 74 (2.7%) patients. Overall, TB diagnosis did not increase mortality.

Conclusion

In this population-based study of rheumatic disease patients from a high incident area, TNF inhibitor exposure was associated with an 18-time increased TB incidence. Adalimumab and certolizumab were associated with greater and earlier TB diagnosis compared to etanercept.

Evaluation of TNF-α cytokine production in patients with tuberculosis compared to healthy people

Background:Mycobacterium tuberculosis (TB) is one of the most important causes of human mortality. Approximately one-third of the world’s population is infected with TB and 5–10% of them develop the active form of the disease. Cytokines play a major role in the host defense process against Mycobacterium infections. Among these cytokines, tumor necrosis factor alpha (TNF-α) has a prominent role in the defense of and pathological responses to tuberculosis.

Materials and methods: A case-control study was carried out from May 2016 to June 2017. 45 patients with diagnosis of tuberculosis (smear and positive culture) were included as case group and 45 healthy subjects as control group. The serum levels of TNF-α were determined with the enzyme-linked immunosorbent assay (ELISA) method.

Results: The concentration of TNF-α in patients with TB was significantly higher than in the control group (P<0.05). However, the difference was only significant in the age groups 20–30 and 50–60 years; in the age groups 30–40, 40–50 and 50–70 years, the difference was not significant, although certain trends were apparent.

Discussion and conclusion: Since the level of serum TNF-α is higher in patients with pulmonary tuberculosis than in individuals without it, the measurement of TNF-α levels can be useful as a probable marker for the diagnosis of tuberculosis.

Evaluation of cytokines in peripheral blood mononuclear cell supernatants for the diagnosis of tuberculosis

INTRODUCTION

There is active interest in leveraging host immune responses as biomarkers of tuberculosis (TB) disease activity. We had previously evaluated an immunodiagnostic test called the antibody in lymphocyte supernatant (ALS) assay. Here, we aimed to evaluate a panel of inflammatory mediators and associate the responses with the ALS results to identify a biosignature to distinguish TB cases from controls.

METHODOLOGY

In this case-control study, adults with TB were compared to controls who were hospitalized for non-infectious conditions. Blood was collected at baseline and after 4 weeks of TB treatment (from TB cases only). Peripheral blood mononuclear cells were isolated and cultured without antigenic stimulation for 72 hours. Inflammatory mediators were measured using the Multiplex cytokine kit and compared between TB cases and controls; among TB cases, responses were compared over time. ALS and inflammatory mediator results were evaluated using generalized discriminant analysis to identify the optimal biosignature to predict TB.

RESULTS

When comparing inflammatory mediators between groups, IL-1ra, IL-1β, and granulocyte macrophage-colony stimulating factor (GM-CSF) were lower in TB cases (P<0.002). Fibroblast growth factor-basic significantly increased from baseline to week-4 (P=0.002). Generalized discriminant analysis yielded a model with IL-2, tumor necrosis factor-alpha, vascular endothelial growth factor, and ALS, providing a sensitivity of 82.2% and specificity of 76.2%.

CONCLUSION

Our results suggest that IL-1ra, IL-1β, and GM-CSF might be used as diagnostic biomarkers to distinguish between TB cases and non-TB cases. We could not identify a group of mediators that outperformed the diagnostic accuracy of the ALS alone.

Lethal disseminated tuberculosis in patients under biological treatment - two clinical cases and a short review

Tumour necrosis factor (TNF)-α inhibitors are highly used in Romania for the treatment of autoimmune disorders, such as rheumatoid arthritis (RA), psoriasis, inflammatory bowel diseases, and ankylosing spondylitis. Biological therapy using TNF-α inhibitors is very effective but is associated with an increased risk of opportunistic infections, including active tuberculosis. Here, two cases are presented of patients with RA and psoriasis under biological therapy who developed very aggressive forms of disseminated tuberculosis, with a rapid progression to death. The authors conclude that patients undergoing biological therapy require thorough evaluation prior to initiating treatment, followed by continuous and rigorous monitoring by a multidisciplinary team during biological treatment, particularly in countries with a high incidence of tuberculosis.

[Cytokine neutralization at specific cellular source : A new therapeutic paradigm? German Version]

BACKGROUND

Currently, treatment of autoimmune diseases is based on manipulation of general control mechanisms, including those mediated by immunoregulatory cytokines. This approach is non-curative and may cause unwanted side effects due to numerous beneficial and non-redundant functions of a particular cytokine.

METHODS

Techniques of reverse genetics, such as conditional gene targeting, were employed to uncover the contributions of two proinflammatory and immunomodulatory cytokines, tumour necrosis factor (TNF) and interleukin 6 (IL-6), in various disease states.

RESULTS

Several non-redundant functions of TNF from distinct cellular sources were identified. TNF from myeloid cells is pathogenic in several autoimmune diseases, whereas TNF produced by T cells showed non-redundant protective functions in experimental arthritis and in a Mycobacterium tuberculosis infection model. To test the idea of selective pharmacological inhibition of "bad" TNF produced by myeloid cells while sparing "good" TNF produced by T lymphocytes, a myeloid-specific TNF inhibitor (MYSTI) was designed - a recombinant mini-antibody with dual specificity that can bind to the surface molecule F4/80 on myeloid cells and to TNF. In vitro experiments confirmed retention of TNF on the surface of TNF-producing cells and in vivo experiments indicated that MYSTI can protect mice from lethal TNF-mediated hepatotoxicity. MYSTI is also effective in experimental arthritis.

CONCLUSION

The proposed therapeutic strategy may be more effective than systemic anti-cytokine therapy in several human autoimmune diseases, as it would preserve the potentially beneficial effects of the same cytokine produced by other cell types. Such bispecific biological agents may become interesting tools for experimental studies and, eventually, drug development.

Practical Management of Respiratory Comorbidities in Patients with Rheumatoid Arthritis

Lung disease is one of the most common causes of extra-articular morbidity and mortality in patients with rheumatoid arthritis (RA). Development of pulmonary manifestations may be due to the systemic disease itself; to serious respiratory adverse events such as pneumonitis and infections secondary to therapy; or to lifestyle habits such as smoking. Rheumatologists often need to make important treatment decisions and plan future care in RA patients with respiratory comorbidities, despite the absence of clear evidence or consensus. In this review we evaluate the clinical assessment and management of RA-associated interstitial lung disease, bronchiectasis, serious (including opportunistic) infection, and smoking-related diseases. We summarize the international recommendations for the management of such conditions where available, refer to published best practice on the basis of scientific literature, and propose practical management suggestions to aid informed decision-making.

Tumor Necrosis Factor-Alpha: Role in Development of Insulin Resistance and Pathogenesis of Type 2 Diabetes Mellitus

Pathogenesis of type 2 diabetes mellitus (T2DM) and development of insulin resistance are characterized by multi-stimuli factors notably glucolipotoxicity, generation of reactive oxygen species (ROS), epigenetic factors, activation of various transcriptional mediated pathways along with the augmented levels of various pro-inflammatory cytokines. Among the various pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) is one the most important pro-inflammatory mediator that is critically involved in the development of insulin resistance and pathogenesis of T2DM. TNF-α is mainly produced in adipocytes and/or peripheral tissues, and induces tissue-specific inflammation through the involvement of generation of ROS and activation of various transcriptional mediated pathways. The raised level of TNF-α induces insulin resistance in adipocytes and peripheral tissues by impairing the insulin signaling through serine phosphorylation that leads to the development of T2DM. Anti-TNF-α treatment strategies have been developed to reduce the incidence of insulin resistance and development of T2DM. In this article, we have briefly described how TNF-α plays crucial role to induce insulin resistance and pathogenesis of T2DM. To block the inflammatory responses by blocking TNF-α and TNF-α signaling may be an effective strategy for the treatment of insulin resistance and T2DM. J. Cell. Biochem. 119: 105-110, 2018. © 2017 Wiley Periodicals, Inc.

Cytokine neutralization at specific cellular source : A new therapeutic paradigm?

BACKGROUND

Currently, treatment of autoimmune diseases is based on manipulation of general control mechanisms, including those mediated by immunoregulatory cytokines. This approach is non-curative and may cause unwanted side effects due to numerous beneficial and non-redundant functions of a particular cytokine.

METHODS

Techniques of reverse genetics, such as conditional gene targeting, were employed to uncover the contributions of two proinflammatory and immunomodulatory cytokines, tumour necrosis factor (TNF) and interleukin 6 (IL-6), in various disease states.

RESULTS

Several non-redundant functions of TNF from distinct cellular sources were identified. TNF from myeloid cells is pathogenic in several autoimmune diseases, whereas TNF produced by T cells showed non-redundant protective functions in experimental arthritis and in a Mycobacterium tuberculosis infection model. To test the idea of selective pharmacological inhibition of "bad" TNF produced by myeloid cells while sparing "good" TNF produced by T lymphocytes, a myeloid-specific TNF inhibitor (MYSTI) was designed-a recombinant mini-antibody with dual specificity that can bind to the surface molecule F4/80 on myeloid cells and to TNF. In vitro experiments confirmed retention of TNF on the surface of TNF-producing cells and in vivo experiments indicated that MYSTI can protect mice from lethal TNF-mediated hepatotoxicity. MYSTI is also effective in experimental arthritis.

CONCLUSION

The proposed therapeutic strategy may be more effective than systemic anti-cytokine therapy in several human autoimmune diseases, as it would preserve the potentially beneficial effects of the same cytokine produced by other cell types. Such bispecific biological agents may become interesting tools for experimental studies and, eventually, drug development.

Tumor necrosis factor alpha neutralization has no direct effect on parasite burden, but causes impaired IFN-γ production by spleen cells from human visceral leishmaniasis patients

The pro-inflammatory cytokine tumor necrosis factor (TNF)-α has an important role in control of experimental Leishmania donovani infection. Less is known about the role of TNF-α in human visceral leishmaniasis (VL). Evidence for a protective role is primarily based on case reports of VL development in individuals treated with TNF-α neutralizing antibody. In this study, we have evaluated how TNF-α neutralization affects parasite replication and cytokine production in ex vivo splenic aspirates (SA) from active VL patients. The effect of TNF-α neutralization on cell mediated antigen specific responses were also evaluated using whole blood cultures. Neutralization of TNF-α did not affect parasite numbers in SA cultures. Interferon (IFN)-γ levels were significantly reduced, but interleukin (IL)-10 levels were unchanged in these cultures. Leishmania antigen stimulated SA produced significant TNF-α which suggests that TNF-α is actively produced in VL spleen. Further it stimulates IFN-γ production, but no direct effect on parasite replication.

Virulence-Dependent Alterations in the Kinetics of Immune Cells during Pulmonary Infection by Mycobacterium tuberculosis

A better understanding of the kinetics of accumulated immune cells that are involved in pathophysiology during Mycobacterium tuberculosis (Mtb) infection may help to facilitate the development of vaccines and immunological interventions. However, the kinetics of innate and adaptive cells that are associated with pathogenesis during Mtb infection and their relationship to Mtb virulence are not clearly understood. In this study, we used a mouse model to compare the bacterial burden, inflammation and kinetics of immune cells during aerogenic infection in the lung between laboratory-adapted strains (Mtb H37Rv and H37Ra) and Mtb K strain, a hyper-virulent W-Beijing lineage strain. The Mtb K strain multiplied more than 10- and 3.54-fold more rapidly than H37Ra and H37Rv, respectively, during the early stage of infection (at 28 days post-infection) and resulted in exacerbated lung pathology at 56 to 112 days post-infection. Similar numbers of innate immune cells had infiltrated, regardless of the strain, by 14 days post-infection. High, time-dependent frequencies of F4/80^-CD11c⁺CD11b^-Siglec-H⁺PDCA-1⁺ plasmacytoid DCs and CD11c^-CD11b⁺Gr-1^int cells were observed in the lungs of mice that were infected with the Mtb K strain. Regarding adaptive immunity, Th1 and Th17 T cells that express T-bet and RORγt, respectively, significantly increased in the lungs that were infected with the laboratory-adapted strains, and the population of CD4⁺CD25⁺Foxp3⁺ regulatory T cells was remarkably increased at 112 days post-infection in the lungs of mice that were infected with the K strain. Collectively, our findings indicate that the highly virulent Mtb K strain may trigger the accumulation of pDCs and Gr1^intCD11b⁺ cells with the concomitant down-regulation of the Th1 response and the maintenance of an up-regulated Th2 response without inducing a Th17 response during chronic infection. These results will help to determine which immune system components must be considered for the development of tuberculosis (TB) vaccines and immunological interventions.

Molecular and biochemical characterization of recombinant guinea pig tumor necrosis factor-alpha

Tumor necrosis factor alpha (TNF-α) is a cytokine which plays opposing roles in the context of infectious disease pathogenesis. TNF-α is essential for the development of a protective immune response to some pathogens, for example, Mycobacterium tuberculosis, by synergizing with other cytokines. However, exorbitant or uncontrolled TNF-α activity may also drive pathology and disease symptoms in many infectious diseases. In order to elucidate the beneficial and detrimental roles of TNF-α in tuberculosis (TB) and other diseases for which the guinea pig is the small animal model of choice, recombinant guinea pig (rgp)TNF-α has been produced using prokaryotic expression systems. However, it is unknown whether posttranslational modifications which cannot be made in the prokaryotic expression systems may be important for rgpTNF-α structure and function. Therefore, we carried out a comparative study by expressing rgpTNF-α in prokaryotic and eukaryotic expression systems and analyzed the eukaryotic-expressed rgpTNF-α for the presence of posttranslational modifications by subjecting it to NanoLC-MS/MS. We conclude that the eukaryotic-expressed rgpTNF-α lacks posttranslational modifications, and we found no significant difference in terms of the biological activity between prokaryotic- and eukaryotic-expressed rgpTNF-α. Taken together, results from our study show that a prokaryotic expression system can be used for generating large amounts of rgpTNF-α without concern for the biological integrity.

Nontuberculous mycobacteria infections in immunosuppressed hosts

Diseases and therapies that reduce cell-mediated immunity increase the risk of nontuberculous mycobacterial (NTM) disease. Extrapulmonary NTM disease, including disseminated, skin, and catheter-related disease, is more common in immunosuppressed than immunocompetent patients. Mycobacterium avium complex remains the most common cause of NTM infection, but rapid growers including Mycobacterium abscessus, Mycobacterium chelonae, and Mycobacterium fortuitum play an important role in skin and catheter-related infections. With the exception of antibiotic prophylaxis for AIDS patients, the prevention of NTM remains difficult. Management is complicated, involving restoration of immune function and removal of catheters in addition to treatment with species-specific antibiotics per current guidelines.

Pulmonary tuberculosis in Asian elephants (Elephas maximus): histologic lesions with correlation to local immune responses

Although Mycobacterium tuberculosis infection is an important health concern for Asian elephants (Elephas maximus), no studies have evaluated the associated local immune responses or histologic lesions. In primates including humans, latent tuberculosis is distinguished by well-organized granulomas with TH1 cytokine expression, whereas active disease is characterized by poorly organized inflammation and local imbalance in TH1/TH2 cytokines. This study examined archival, formalin-fixed, paraffin-embedded lung samples from 5 tuberculosis-negative and 9 tuberculosis-positive Asian elephants. Lesions were assessed by light microscopy, and lymphoid infiltrates were characterized by CD3 and CD20 immunolabeling. Expression of TH1 (interferon [IFN]-γ, tumor necrosis factor [TNF]-α) and TH2 (interleukin [IL]-4, IL-10, transforming growth factor [TGF]-β) cytokines was determined using in situ hybridization. In 6 of 9 samples, inflammation was similar to the pattern of primate active disease with low to moderate numbers of lymphocytes, most of which were CD20 positive. In 1 sample, inflammation was most similar to latent tuberculosis in primates with numerous CD3-positive lymphocytes. Expression of IFN-γ was detected in 3 of 8 tuberculosis-positive samples. Expression of TNF-α was detected in 3 of 8 positive samples, including the one with latent morphology. Low-level expression of IL-4 was present in 4 of 8 positive samples. Only single positive samples displayed expression of IL-10 and TGF-β. Tuberculosis-negative samples generally lacked cytokine expression. Results showed heterogeneity in lesions of elephant tuberculosis similar to those of latent and active disease in primates, with variable expression of both TH1 and TH2 cytokines.

Normalization of the levels of inflammatory molecules in Mycobacterium smegmatis-infected U937 cells by fibrate pretreatment

BACKGROUND

Tuberculosis (TB) is a respiratory tract disease caused by Mycobacterium tuberculosis infection. M. tuberculosis exploits immune privilege to grow and divide in pleural macrophages. Fibrates are associated with the immune response and control lipid metabolism through glycolysis with β-oxidation of fatty acids.

RESULTS

In this study, we investigated the effect of fibrate pretreatment on the immune response during M. smegmatis infection in U937 cells, a human leukemic monocyte lymphoma cell line. The protein expression of tumor necrosis factor α (TNF-α), an inflammatory marker, and myeloid differentiation primary response gene 88 (MyD88), a toll like receptor adaptor molecule, in the infected group increased at 1 and 6 h after M. smegmatis infection of U937 cells. Acetyl coenzyme A acetyl transferase-1 (ACAT-1), peroxisome proliferator-activated receptor-α (PPAR-α), TNF-α, and MyD88 decreased in U937 cells treated with fibrates at 12 and 24 h after treatment. More than a 24 h pretreatment with fibrate resulted in similar expression levels of ACAT-1 and PPAR-α between infected vehicle control and infected groups which were pretreated with fibrate for 24 h. However, upon exposure to M. smegmatis, the cellular expression of the TNF-α and MyD88 in the infected groups pretreated with fibrate for 24 h decreased significantly compared to that in the infected vehicle group.

CONCLUSION

These results suggest that fibrate pretreatment normalized the levels of inflammatory molecules in Mycobacterium smegmatis-infected U937 cells. Further studies are needed to confirm the findings on pathophysiology and immune defense mechanism of U937 by fibrates during M. tuberculosis infection.

Etanercept exacerbates inflammation and pathology in a rabbit model of active pulmonary tuberculosis

Treatment of chronic inflammatory diseases with tumor necrosis factor alpha (TNF-α) antagonists has been associated with increased risk of tuberculosis (TB). We examined the usefulness of the rabbit model of active pulmonary TB for studying the impact of the human immune modulatory reagent etanercept on the host immune response. Control of Mycobacterium tuberculosis (Mtb) infection, disease pathology, and the global transcriptional response in Mtb-infected lungs of rabbits were studied. Etanercept treatment exacerbated disease pathology and reduced bacillary control in the lungs, compared with infected untreated animals. Reduced collagen and fibrin deposition in the granulomas was associated with significant downregulation of the collagen metabolism and fibrosis network genes and upregulation of genes in the inflammatory response and cell recruitment networks in the lungs of etanercept treated, compared with untreated rabbits. Our results suggest that targeting the TNF-α signaling pathway disrupts the tissue remodeling process, which is required for the formation and maintenance of well-differentiated granulomas and for control of Mtb growth in the lungs. These results validate the use of the rabbit model for investigating the impact of selected human immune modulatory drugs, such as a TNF-α antagonist, on the host immune response and pathogenesis in TB.

Prokaryotic expression and functional analysis of the Mb1514 gene in Mycobacterium bovis

The ability of mycobacteria to grow and invade target tissues is the key component in the process of Mycobacterium bovis infection. Therefore, analysis of the proteins responsible for cell invasion will assist clinicians in combating bovine tuberculosis. The Mb1514 gene of M. bovis encodes a hypothetical invasion protein (designated here as MbINV protein), whose function has not yet been directly identified. In this study, the Mb1514 gene from M. bovis was cloned, and expressed in E. coli. The recombinant MbINV protein (a single band of approximately 28 kDa) was purified for biological analysis. Our data demonstrated that recombinant MbINV protein significantly inhibited the viability of RAW264.7 macrophages in a dose-dependent manner (P < 0.05), and induced cell necrosis, indicating that the protein is toxic. MbINV protein infection significantly enhanced the mRNA expression levels of TNF-α, IL-1β, and NOS2 (P < 0.01), suggesting that MbINV protein may be one of the virulence factors which directly interact with macrophages and modulate the host immune response to M. bovis. An invasion inhibition assay showed that MbINV-inhibited M. bovis invasion of RAW264.7 cells in a concentration-dependant manner, demonstrating it is an invasion protein.

Dual mechanism for Mycobacterium tuberculosis cytotoxicity on lung epithelial cells

Mycobacterium tuberculosis strains CDC1551 and Erdman were used to assess cytotoxicity in infected A549 human alveolar epithelial cell monolayers. Strain CDC1551 was found to induce qualitatively greater disruption of A549 monolayers than was strain Erdman, although total intracellular and cell-associated bacterial growth rates over the course of the infections were not significantly different. Cell-free culture supernatants from human monocytic cells infected with either of the 2 M. tuberculosis strains produced a cytotoxic effect on A549 cells, correlating with the amount of tumor necrosis factor alpha (TNF-α) released by the infected monocytes. The addition of TNF-α-neutralizing antibodies to the supernatants from infected monocyte cultures did prevent the induction of a cytotoxic effect on A549 cells overlaid with this mixture but did not prevent the death of epithelial cells when added prior to infection with M. tuberculosis bacilli. Thus, these data agree with previous observations that lung epithelial cells infected with M. tuberculosis bacilli are rapidly killed in vitro. In addition, the data indicate that some of the observed epithelial cell killing may be collateral damage; the result of TNF-α released from M. tuberculosis-infected monocytes.

Reactivation of M. tuberculosis infection in trans-membrane tumour necrosis factor mice

Of those individuals who are infected with M. tuberculosis, 90% do not develop active disease and represents a large reservoir of M. tuberculosis with the potential for reactivation of infection. Sustained TNF expression is required for containment of persistent infection and TNF neutralization leads to tuberculosis reactivation. In this study, we investigated the contribution of soluble TNF (solTNF) and transmembrane TNF (Tm-TNF) in immune responses generated against reactivating tuberculosis. In a chemotherapy induced tuberculosis reactivation model, mice were challenged by aerosol inhalation infection with low dose M. tuberculosis for three weeks to establish infection followed chemotherapeutic treatment for six weeks, after which therapy was terminated and tuberculosis reactivation investigated. We demonstrate that complete absence of TNF results in host susceptibility to M. tuberculosis reactivation in the presence of established mycobacteria-specific adaptive immunity with mice displaying unrestricted bacilli growth and diffused granuloma structures compared to WT control mice. Interestingly, bacterial re-emergence is contained in Tm-TNF mice during the initial phases of tuberculosis reactivation, indicating that Tm-TNF sustains immune pressure as in WT mice. However, Tm-TNF mice show susceptibility to long term M. tuberculosis reactivation associated with uncontrolled influx of leukocytes in the lungs and reduced IL-12p70, IFNγ and IL-10, enlarged granuloma structures, and failure to contain mycobacterial replication relative to WT mice. In conclusion, we demonstrate that both solTNF and Tm-TNF are required for maintaining immune pressure to contain reactivating M. tuberculosis bacilli even after mycobacteria-specific immunity has been established.

Soluble TNF, but not membrane TNF, is critical in LPS-induced hepatitis

BACKGROUND & AIMS

: Bacillus Calmette-Guérin (BCG) infection causes hepatic injury following granuloma formation and secretion of cytokines which renders mice highly sensitive to endotoxin-mediated hepatotoxicity. Tumor necrosis factor (TNF) is required for granuloma formation and is one of the most important cytokines in liver injury. TNF inhibitors are effective therapies for inflammatory diseases. However, clinical use of non-selective TNF inhibitors is associated with an increased risk of infections. This work investigates the differential roles of soluble TNF (solTNF) and membrane TNF (memTNF) in BCG infection, BCG/LPS- and D-GALN/LPS-induced liver injury.

METHODS

We have used both genetic and pharmacologic approaches and analyzed liver injury, TLR4, cytokine and iNOS activation induced by BCG, BCG/LPS and D-GALN/LPS.

RESULTS

BCG infection-induced liver injury is seen in wild-type mice but not in TNF(-/-), memTNF knock-in (KI), and sTNFR1-Fc transgenic mice. Severity of BCG-induced liver injury is correlated with BCG-granuloma number and hepatic expression of TLR4 and iNOS. In addition, protection from liver damage caused by BCG/LPS or D-GALN/LPS administration was observed in TNF(-/-), memTNF KI and sTNFR1-Fc transgenic mice. To extend the genetic findings, we then evaluated whether selective pharmacological inhibition of solTNF by dominant-negative (DN)-TNF neutralization and non-selective inhibition of solTNF and memTNF by anti-TNF antibodies and etanercept (TNFR2-IgG1) can protect the mice from liver injury. Both selective and non-selective inhibition of solTNF protected mice from BCG/LPS and D-GALN/LPS-induced liver damage.

CONCLUSIONS

These data suggest that memTNF is not mediating liver injury and that selective inhibition of solTNF sparing memTNF may represent a new therapeutic strategy to treat immune-mediated inflammatory liver diseases.

TNF and IL-10 are major factors in modulation of the phagocytic cell environment in lung and lymph node in tuberculosis: a next-generation two-compartmental model

Tuberculosis (TB) is one of the earliest recorded human diseases and still one of the deadliest worldwide. Its causative agent is the bacteria Mycobacterium tuberculosis (Mtb). Cytokine-mediated macrophage activation is a necessary step in control of bacterial growth, and early immunologic events in lymph node and lung are crucial to the outcome of infection, although the factors that influence these environments and the immune response are poorly understood. Our goal is to build the next-generation two-compartmental model of the immune response to provide a gateway to more spatial and mechanistic investigations of M. tuberculosis infection in the LN and lung. Crucial immune factors emerge that affect macrophage populations and inflammation, namely TNF-dependent recruitment and apoptosis, and IL-10 levels. Surprisingly, bacterial load plays a less important role than TNF in increasing the population of infected macrophages and inflammation. Using a mathematical model, it is possible to distinguish the effects of pro-inflammatory (TNF) and anti-inflammatory (IL-10) cytokines on the spectrum of phagocyte populations (macrophages and dendritic cells) in the lung and lymph node. Our results suggest that TNF is a major mediator of recruitment of phagocytes to the lungs. In contrast, IL-10 plays a role in balancing the dominant macrophage phenotype in LN and lung.

Modelling the time to onset of adverse reactions with parametric survival distributions: a potential approach to signal detection and evaluation

BACKGROUND

It has been postulated that the time to onset of adverse drug reactions is connected to the underlying pharmacological (or toxic) mechanism of adverse drug reactions whether the reaction is time dependent or not.

OBJECTIVE

We have conducted a preliminary study using the parametric modelling of the time to onset of adverse reactions as an approach to signal detection on spontaneous reporting system databases.

METHODS

We performed a parametric modelling of the reported time to onset of adverse drug reactions for which the underlying toxic mechanism is characterized. For the purpose of our study, we have used the reported liver injuries associated with bosentan, and the infections associated with the use of the tumour necrosis factor (TNF) inhibitors, adalimumab, etanercept and infliximab, which are used in Crohn's disease and rheumatoid arthritis, reported to EudraVigilance between December 2001 and September 2006.

RESULTS

The main results reflect the fact that the reported time to onset is a surrogate of the true time to onset of the reaction and combines three hazards (occurrence, diagnosis and reporting) that cannot be disentangled. Consequently, the modelling of the time to onset of reactions reported with TNF inhibitors showed differences that could reflect different pharmacological activities, indications, monitoring of the patients or different reporting patterns. These variations could also limit the interpretation of the parametric modelling.

CONCLUSIONS

Some consistency that was found between the occurrences of the infections with the TNF inhibitors suggests a causal association. There are statistical issues that are important to keep in mind when interpreting the results (the impact of the data quality on the fit of the distributions and the absence of a test of hypothesis linked to the absence of a relevant comparator). The study suggests that the modelling of the reported time to onset of adverse reactions could be a useful adjunct to other signal detection methods.

Identification of key processes that control tumor necrosis factor availability in a tuberculosis granuloma

Tuberculosis (TB) granulomas are organized collections of immune cells comprised of macrophages, lymphocytes and other cells that form in the lung as a result of immune response to Mycobacterium tuberculosis (Mtb) infection. Formation and maintenance of granulomas are essential for control of Mtb infection and are regulated in part by a pro-inflammatory cytokine, tumor necrosis factor-α (TNF). To characterize mechanisms that control TNF availability within a TB granuloma, we developed a multi-scale two compartment partial differential equation model that describes a granuloma as a collection of immune cells forming concentric layers and includes TNF/TNF receptor binding and trafficking processes. We used the results of sensitivity analysis as a tool to identify experiments to measure critical model parameters in an artificial experimental model of a TB granuloma induced in the lungs of mice following injection of mycobacterial antigen-coated beads. Using our model, we then demonstrated that the organization of immune cells within a TB granuloma as well as TNF/TNF receptor binding and intracellular trafficking are two important factors that control TNF availability and may spatially coordinate TNF-induced immunological functions within a granuloma. Further, we showed that the neutralization power of TNF-neutralizing drugs depends on their TNF binding characteristics, including TNF binding kinetics, ability to bind to membrane-bound TNF and TNF binding stoichiometry. To further elucidate the role of TNF in the process of granuloma development, our modeling and experimental findings on TNF-associated molecular scale aspects of the granuloma can be incorporated into larger scale models describing the immune response to TB infection. Ultimately, these modeling and experimental results can help identify new strategies for TB disease control/therapy.

Tuberculosis is a common and deadly infectious disease caused by a highly successful bacterium, Mycobacterium tuberculosis (Mtb). Multiple host immune factors control the formation of a self-organizing aggregate of immune cells termed a granuloma in the lungs after inhalation of Mtb. One such factor, tumor necrosis factor-α (TNF), is a protein that regulates inflammatory immune responses. Availability of TNF within a TB granuloma has been proposed to have a critical role in the protective immunity against TB. However, direct measurement of the level of TNF in a granuloma is not experimentally feasible. Therefore, we develop a mathematical model based on an experimental model of granuloma developed in mice to predict TNF availability in a granuloma. We measure values of critical model parameters and explore mechanisms that influence TNF availability in the granuloma. We find that cellular organization in a granuloma and intracellular trafficking of TNF control TNF availability in a granuloma. Further, our model analysis also highlights anti-TNF drug properties that determine their TNF neutralization power. Our findings complement and extend those of recent studies on the role of TNF in the immune response against TB.

Induction of Treg by monocyte-derived DC modulated by vitamin D3 or dexamethasone: differential role for PD-L1

Specific therapy with modulated DC may restore immunological tolerance, thereby obviating the need for chronic immunosuppression in transplantation or autoimmunity. In this study we compared the tolerizing capacity of dexamethasone (Dex)- and 1 alpha,25-dihydroxyvitamin D3 (VD3)-modulated DC. Treatment of monocytes with either VD3 or Dex resulted in DC with stable, semi-mature phenotypes compared with standard DC, with intermediate levels of co-stimulatory and MHC class II molecules, which remained unaltered after subsequent pro-inflammatory stimulation. IL-12p70 secretion was lost by VD3- and Dex-DC, whereas IL-10 secretion was unaffected. VD3-DC distinctly produced large amounts of TNF-alpha. Both VD3- and Dex-DC possessed the capacity to convert CD4 T cells into IL-10-secreting Treg potently suppressing the proliferation of responder T cells. However, only Treg induced by VD3-DC exhibited antigen specificity. VD3-, but not Dex-, DC expressed significant high levels of PD-L1 (programmed death-1 ligand), upon activation. Blockade of PD-L1 during priming redirected T cells to produce IFN-gamma instead of IL-10 and abolished acquisition of regulatory capacity. Our findings demonstrate that both VD3- and Dex-DC possess durable but differential tolerogenic features, acting via different mechanisms. Both are potentially useful to specifically down-regulate unwanted immune responses and induce immune tolerance. These modulated DC appear suitable as adjuvant in antigen-specific clinical vaccination intervention strategies.

Attenuation of toll-like receptor expression and function in latent tuberculosis by coexistent filarial infection with restoration following antifilarial chemotherapy

Mycobacterium tuberculosis (Mtb) and filarial coinfection is highly prevalent, and the presence of filarial infections may regulate the Toll-like receptor (TLR)-dependent immune response needed to control Mtb infection. By analyzing the baseline and mycobacterial antigen–stimulated expression of TLR1, 2, 4, and 9 (in individuals with latent tuberculosis [TB] with or without filarial infection), we were able to demonstrate that filarial infection, coincident with Mtb, significantly diminishes both baseline and Mtb antigen-specific TLR2 and TLR9 expression. In addition, pro-inflammatory cytokine responses to TLR2 and 9 ligands are significantly diminished in filaria/TB-coinfected individuals. Definitive treatment of lymphatic filariasis significantly restores the pro-inflammatory cytokine responses in individuals with latent TB. Coincident filarial infection exerted a profound inhibitory effect on protective mycobacteria-specific TLR-mediated immune responses in latent tuberculosis and suggests a novel mechanism by which concomitant filarial infections predispose to the development of active tuberculosis in humans.

Lymphatic filariasis afflicts over 120 million people worldwide, while Mycobacterium tuberculosis infects over 2 billion people worldwide. Almost 90% of infected people harbor latent tuberculosis infection with no clinical manifestations. Toll-like receptors (TLRs), pattern-recognition receptors that are present on host immune cells, constitute an important facet of host immune response initiation against a variety of pathogens. Because lymphatic filariasis and tuberculosis are co-endemic in many parts of the world and because TLR modulation is an important feature of both infections, we examined the effect of coexisting filarial infection on TLR-specific immune responses in latent tuberculosis by comparing cellular immune responses to Toll ligands in individuals with latent tuberculosis with or without concomitant lymphatic filariasis. We first examined modulation of TLRs at the gene expression level and determined that downregulation of TLR2 and 9 is associated with coexisting filarial infection. We then determined that Toll ligand-induced pro-inflammatory cytokine production—which is crucial in host defense against TB—is diminished in the presence of filarial coinfection. Treatment of filarial infection restores cytokine production in individuals with latent TB. Thus, we conclude that coexisting filarial infections might significantly compromise essential immune responses in tuberculosis and that treatment of filarial infections would potentially confer tremendous benefit in combating tuberculosis.

The use of etanercept in a patient with disseminated tuberculosis

Tumor necrosis factor (TNF) is a central regulator of chronic inflammatory diseases and plays a major role in the host immune system against tuberculosis (TB). TNF antagonists, infliximab and etanercept are effective in treating chronic inflammatory diseases by inhibiting TNF, but increase the risk of TB as a result of immunosuppression. Previous studies have shown that the risk of TB is greater in patients who received infliximab than in those who received etanercept and several hypotheses on the action mechanisms of the two agents have been presented in order to explain this difference in the risk of TB. As the clinical use of TNF antagonists increase, the incidence rate of TB may increase. Therefore, it is necessary that clinicians considering the use of TNF antagonists pay much attention to the prevention and control of TB and understand the mechanisms of action of the TNF antagonists. This case shows that etanercept treatment can be safely administered during the treatment of TB. In the future, additional studies will be needed to determine the safety of etanercept and the optimal time for the administration of etanercept during the TB treatment.