TNF-α blockade impairs in vitro tuberculous granuloma formation and down modulate Th1, Th17 and Treg cytokines

TNFα: TNFR1 signaling inhibits maturation and maintains the pro-inflammatory programming of monocyte-derived macrophages in murine chronic granulomatous disease

Introduction

Loss of NADPH oxidase activity results in proinflammatory macrophages that contribute to hyperinflammation in Chronic Granulomatous Disease (CGD). Previously, it was shown in a zymosan-induced peritonitis model that gp91phox-/- (CGD) monocyte-derived macrophages (MoMacs) fail to phenotypically mature into pro-resolving MoMacs characteristic of wild type (WT) but retain the ability to do so when placed in the WT milieu. Accordingly, it was hypothesized that soluble factor(s) in the CGD milieu thwart appropriate programming.

Methods

We sought to identify key constituents using ex vivo culture of peritoneal inflammatory leukocytes and their conditioned media. MoMac phenotyping was performed via flow cytometry, measurement of efferocytic capacity and multiplex analysis of secreted cytokines. Addition of exogenous TNFα, TNFα neutralizing antibody and TNFR1-/- MoMacs were used to study the role of TNFα: TNFR1 signaling in MoMac maturation.

Results

More extensive phenotyping defined normal MoMac maturation and demonstrated failure of maturation of CGD MoMacs both ex vivo and in vivo. Protein components, and specifically TNFα, produced and released by CGD neutrophils and MoMacs into conditioned media was identified as critical to preventing maturation. Exogenous addition of TNFα inhibited WT MoMac maturation, and its neutralization allowed maturation of cultured CGD MoMacs. TNFα neutralization also reduced production of IL-1β, IL-6 and CXCL1 by CGD cells though these cytokines played no role in MoMac programming. MoMacs lacking TNFR1 matured more normally in the CGD milieu both ex vivo and following adoptive transfer in vivo.

Discussion

These data lend mechanistic insights into the utility of TNFα blockade in CGD and to other diseases where such therapy has been shown to be beneficial.

Emerging Therapeutic Options for Refractory Pulmonary Sarcoidosis: The Evidence and Proposed Mechanisms of Action

Sarcoidosis is a systemic disease with heterogenous clinical phenotypes characterized by non-necrotizing granuloma formation in affected organs. Most disease either remits spontaneously or responds to corticosteroids and second-line disease-modifying therapies. These medications are associated with numerous toxicities that can significantly impact patient quality-of-life and often limit their long-term use. Additionally, a minority of patients experience chronic, progressive disease that proves refractory to standard treatments. To date, there are limited data to guide the selection of alternative third-line medications for these patients. This review will outline the pathobiological rationale behind current and emerging therapeutic agents for refractory or drug-intolerant sarcoidosis and summarize the existing clinical evidence in support of their use.

Antibodies as clinical tools for tuberculosis

Tuberculosis (TB) is a leading cause of morbidity and mortality worldwide. Global research efforts to improve TB control are hindered by insufficient understanding of the role that antibodies play in protective immunity and pathogenesis. This impacts knowledge of rational and optimal vaccine design, appropriate diagnostic biomarkers, and development of therapeutics. Traditional approaches for the prevention and diagnosis of TB may be less efficacious in high prevalence, remote, and resource-poor settings. An improved understanding of the immune response to the causative agent of TB, Mycobacterium tuberculosis (Mtb), will be crucial for developing better vaccines, therapeutics, and diagnostics. While memory CD4+ T cells and cells and cytokine interferon gamma (IFN-g) have been the main identified correlates of protection in TB, mounting evidence suggests that other types of immunity may also have important roles. TB serology has identified antibodies and functional characteristics that may help diagnose Mtb infection and distinguish between different TB disease states. To date, no serological tests meet the World Health Organization (WHO) requirements for TB diagnosis, but multiplex assays show promise for improving the sensitivity and specificity of TB serodiagnosis. Monoclonal antibody (mAb) therapies and serum passive infusion studies in murine models of TB have also demonstrated some protective outcomes. However, animal models that better reflect the human immune response to Mtb are necessary to fully assess the clinical utility of antibody-based TB prophylactics and therapeutics. Candidate TB vaccines are not designed to elicit an Mtb-specific antibody response, but evidence suggests BCG and novel TB vaccines may induce protective Mtb antibodies. The potential of the humoral immune response in TB monitoring and control is being investigated and these studies provide important insight into the functional role of antibody-mediated immunity against TB. In this review, we describe the current state of development of antibody-based clinical tools for TB, with a focus on diagnostic, therapeutic, and vaccine-based applications.

Cutaneous Manifestations of Mycobacterium tuberculosis: A Literature Review

Tuberculosis is an ancient disease that humanity struggled with for centuries and continues to struggle with. The bacteria Mycobacterium tuberculosis often infects the lungs through respiratory transmission and manifests itself through various symptoms, including cutaneous infections. Cutaneous tuberculosis (CTB) comprises about 1% to 1.5% of all extrapulmonary manifestations and is often accompanied by polymorphous lesions, including papules, nodules, plaques, ulcers, gummas, and verrucous lesions. CTB is most commonly observed in low-income, HIV, and immunosuppressed populations, similar to intrapulmonary manifestations. The main pathogen for CTB is M. tuberculosis but less commonly with M. bovis and BCG vaccine, and the modes of transmission are largely classified into exogenous and endogenous CTB. Current treatment options for CTB include oral therapy of antibiotic medications such as rifampicin, streptomycin, ethambutol, isoniazid, and pyrazinamide, which is occasionally combined with surgical intervention.

Virulence Factors of Mycobacterium tuberculosis as Modulators of Cell Death Mechanisms

Mycobacterium tuberculosis (Mtb) modulates diverse cell death pathways to escape the host immune responses and favor its dissemination, a complex process of interest in pathogenesis-related studies. The main virulence factors of Mtb that alter cell death pathways are classified according to their origin as either non-protein (for instance, lipomannan) or protein (such as the PE family and ESX secretion system). The 38 kDa lipoprotein, ESAT-6 (early antigen-secreted protein 6 kDa), and another secreted protein, tuberculosis necrotizing toxin (TNT), induces necroptosis, thereby allowing mycobacteria to survive inside the cell. The inhibition of pyroptosis by blocking inflammasome activation by Zmp1 and PknF is another pathway that aids the intracellular replication of Mtb. Autophagy inhibition is another mechanism that allows Mtb to escape the immune response. The enhanced intracellular survival (Eis) protein, other proteins, such as ESX-1, SecA2, SapM, PE6, and certain microRNAs, also facilitate Mtb host immune escape process. In summary, Mtb affects the microenvironment of cell death to avoid an effective immune response and facilitate its spread. A thorough study of these pathways would help identify therapeutic targets to prevent the survival of mycobacteria in the host.

Evaluation of Specific Cellular and Humoral Immune Response to Toxoplasma gondii in Patients with Autoimmune Rheumatic Diseases Immunomodulated Due to the Use of TNF Blockers

(1) Background: TNF antagonists have been used to treat autoimmune diseases (AD). However, during the chronic phase of toxoplasmosis, TNF-α and TNFR play a significant role in maintaining disease resistance and latency. Several studies have demonstrated the risk of latent infections’ reactivation in patients infected with toxoplasmosis. Our objective was to verify whether patients with autoimmune rheumatic diseases, who use TNF antagonists and/or synthetic drugs and had previous contact with Toxoplasma gondii (IgG+), present any indication of an increased risk of toxoplasmosis reactivation. (2) Methods: Blood samples were collected, and peripheral blood mononuclear cells (PBMCs) were evaluated after stimulation with antigens of Toxoplasma gondii, with anti-CD3/anti-CD28 or without stimulus, at 48 and 96 h. CD69+, CD28+, and PD-1 stains were evaluated, in addition to intracellular expression of IFN-γ, IL-17, and IL-10 by CD4+ and the presence of regulatory CD4+ T cells by labeling CD25+, FOXP3, and LAP. The cytokines IL-2, IL-4, IL-6, IL-10, IFN-γ, TNF-α, and IL-17 were measured in the culture supernatant after 96 h. Serology for IgG and IgG1 was evaluated. (3) Results: There were no differences in the levels of IgG and IgG1 between the groups, but the IgG1 avidity was reduced in the immunobiological group compared to the control group. All groups exhibited a significant correlation between IgG and IgG1 positivity. CD4+ T lymphocytes expressing PD-1 were increased in individuals suffering from autoimmune rheumatic diseases and using disease-modifying antirheumatic drugs. In addition, treatment with TNF blockers did not seem to influence the populations of regulatory T cells and did not interfere with the expression of the cytokines IFN-γ, IL-17, and IL-10 by CD4+ cells or the production of cytokines by PBMCs from patients with AD. (4) Conclusions: This study presents evidence that the use of TNF-α blockers did not promote an immunological imbalance to the extent of impairing the anti-Toxoplasma gondii immune response and predisposing to toxoplasmosis reactivation.

Bovine Immunity and Vitamin D3: An Emerging Association in Johne's Disease

Mycobacterium avium subspecies paratuberculosis (MAP) is an environmentally hardy pathogen of ruminants that plagues the dairy industry. Hallmark clinical symptoms include granulomatous enteritis, watery diarrhea, and significant loss of body condition. Transition from subclinical to clinical infection is a dynamic process led by MAP which resides in host macrophages. Clinical stage disease is accompanied by dysfunctional immune responses and a reduction in circulating vitamin D₃. The immunomodulatory role of vitamin D₃ in infectious disease has been well established in humans, particularly in Mycobacterium tuberculosis infection. However, significant species differences exist between the immune system of humans and bovines, including effects induced by vitamin D₃. This fact highlights the need for continued study of the relationship between vitamin D₃ and bovine immunity, especially during different stages of paratuberculosis.

Current Research Describing the Role of CD4+ T Lymphocyte Subsets in the Pathogenesis of Granulomatous Lobular Mastitis

Background: Granulomatous lobular mastitis (GLM) is a rare, benign, chronic inflammatory illness of the mammary gland with an unknown cause. Many scholars believe that the pathogenesis of GLM is mediated by autoimmunity. This article reviews the progress of the role of CD4+ T lymphocyte subsets in the development of GLM to explore potential therapeutic targets.Methods: Original articles from inception to October 2021 were systematically searched by two members on PubMed and China National Knowledge Infrastructure.Results: Current studies have confirmed the presence of disorders of several immune molecules in the serum and tissue microenvironment of GLM patients, including interleukin (IL) -2, IL-4, IL-6, and IL-10. This may be related to the dysregulation of Th1/Th2 and Th17/Treg balance.Conclusions: Altered expression and the malfunctioning of Th, Treg, and associated cytokines may contribute to GLM pathogenesis. Immune molecules and immune-related pathways may be potential targets and breakthroughs for future GLM treatment.

Increased susceptibility to pneumonia due to tumour necrosis factor inhibition and prospective immune system rescue via immunotherapy

Immunomodulators such as tumour necrosis factor (TNF) inhibitors are used to treat autoimmune conditions by reducing the magnitude of the innate immune response. Dampened innate responses pose an increased risk of new infections by opportunistic pathogens and reactivation of pre-existing latent infections. The alteration in immune response predisposes to increased severity of infections. TNF inhibitors are used to treat autoimmune conditions such as rheumatoid arthritis, juvenile arthritis, psoriatic arthritis, transplant recipients, and inflammatory bowel disease. The efficacies of immunomodulators are shown to be varied, even among those that target the same pathways. Monoclonal antibody-based TNF inhibitors have been shown to induce stronger immunosuppression when compared to their receptor-based counterparts. The variability in activity also translates to differences in risk for infection, moreover, parallel, or sequential use of immunosuppressive drugs and corticosteroids makes it difficult to accurately attribute the risk of infection to a single immunomodulatory drug. Among recipients of TNF inhibitors, Mycobacterium tuberculosis has been shown to be responsible for 12.5-59% of all infections; Pneumocystis jirovecii has been responsible for 20% of all non-viral infections; and Legionella pneumophila infections occur at 13-21 times the rate of the general population. This review will outline the mechanism of immune modulation caused by TNF inhibitors and how they predispose to infection with a focus on Mycobacterium tuberculosis, Legionella pneumophila, and Pneumocystis jirovecii. This review will then explore and evaluate how other immunomodulators and host-directed treatments influence these infections and the severity of the resulting infection to mitigate or treat TNF inhibitor-associated infections alongside antibiotics.

Restricted Activation of the NF-κB Pathway in Individuals with Latent Tuberculosis Infection after HIF-1α Blockade

Tuberculous granuloma formation is mediated by hypoxia-inducible factor 1 alpha (HIF-1α), and is essential for establishing latent tuberculosis infection (LTBI) and its progression to active tuberculosis (TB). Here, we investigated whether HIF-1α expression and adjacent mechanisms were associated with latent or active TB infection. Patients with active TB, individuals with LTBI, and healthy controls were recruited, and the expression of cytokine genes IL15, IL18, TNFA, IL6, HIF1A, and A20 in peripheral blood mononuclear cells (PBMCs) and serum vitamin D (25(OH)D3) levels were evaluated. Additionally, nuclear factor kappa B (NF-κB) and tumor necrosis factor-alpha (TNF-α) levels were analyzed in PBMC lysates and culture supernatants, respectively, after HIF-1α blockade with 2-methoxyestradiol. We observed that IL-15 expression was higher in individuals with LTBI than in patients with active TB, while IL-18 and TNF-α expression was similar between LTBI and TB groups. Additionally, serum 25(OH)D3 levels and expression of IL-6, HIF1A, and A20 were higher in patients with active TB than in individuals with LTBI. Moreover, PBMCs from individuals with LTBI showed decreased NF-κB phosphorylation and increased TNF-α production after HIF-1α blockade. Together, these results suggest that under hypoxic conditions, TNF-α production and NF-κB pathway downregulation are associated with the LTBI phenotype.

Assessment of Experimental Techniques That Facilitate Human Granuloma Formation in an In Vitro System: A Systematic Review

The process of granuloma formation is complex, and due to species differences, the validity of animal studies is somewhat questioned. Moreover, the large number of animals needed to observe the different stages of development also raises ethical questions. Therefore, researchers have explored the use of human peripheral blood mononuclear cells (PBMCs), a heterogeneous population of immune cells, in an in vitro model. This review included in vitro studies that focused on exposing PBMCs—from healthy, sensitized, or diseased individuals—to antigens derived from infectious agents—such as mycobacteria or Schistosoma spp.—or inorganic antigens—such as beryllium. The reviewed studies mainly explored how human in vitro granuloma models can contribute towards understanding the pathogenesis of granulomatous diseases, especially during the early stages of granuloma formation. The feasibility of granuloma modelling was thus largely assessed via experimental techniques including (1) granuloma scoring indices (GI), (2) cell surface markers and (3) cytokine secretion profiling. While granuloma scoring showed some similarities between studies, a large variability of culture conditions and endpoints measured have been identified. The lack of any standardization currently impedes the success of a human in vitro granuloma model.

Identifying Infliximab- (IFX-) Responsive Blood Signatures for the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a severe chronic pathogenic inflammatory abnormality that damages small joints. Comprehensive diagnosis and treatment procedures for RA have been established because of its severe symptoms and relatively high morbidity. Medication and surgery are the two major therapeutic approaches. Infliximab (IFX) is a novel biological agent applied for the treatment of RA. IFX improves physical functions and benefits the achievement of clinical remission even under discontinuous medication. However, not all patients react to IFX, and distinguishing IFX-sensitive and IFX-resistant patients is quite difficult. Thus, how to predict the therapeutic effects of IFX on patients with RA is one of the urgent translational medicine problems in the clinical treatment of RA. In this study, we present a novel computational method for the identification of the applicable and substantial blood gene signatures of IFX sensitivity by liquid biopsy, which may assist in the establishment of a clinical drug sensitivity test standard for RA and contribute to the revelation of unique IFX-associated pharmacological mechanisms.

Tuberculosis in Biologic-naïve Patients With Rheumatoid Arthritis: Risk Factors and Tuberculosis Characteristics

OBJECTIVE

To investigate risk factors and characteristics of active tuberculosis (TB) in biologic-naïve patients with rheumatoid arthritis (RA).

METHODS

We conducted a population-based case-control study using the Swedish Rheumatology Quality Register, the National Patient Register, and the Tuberculosis Register to identify RA patients with active TB and matched RA controls without TB between 2001-2014. Clinical data were obtained from medical records. TB risk was estimated as adjusted OR (aOR) with 95% CI using univariate and multivariable logistic regression analyses.

RESULTS

After validation of diagnoses, the study included 31 RA patients with TB and 122 matched RA controls. All except 3 cases had reactivation of latent TB. Pulmonary TB was most prevalent (84%). Ever use of methotrexate was not associated with increased TB risk (aOR 0.8, 95% CI 0.3-2.0), whereas ever treatment with leflunomide (aOR 6.0, 95% CI 1.5-24.7), azathioprine (aOR 3.8, 95% CI 1.1-13.8), and prednisolone (PSL; aOR 2.4, 95% CI 1.0-6.0) was. There were no significant differences between maximum dose of PSL, treatment duration with PSL before TB, or cumulative dose of PSL the year before TB diagnosis between cases and controls. Obstructive pulmonary disease was associated with an increased TB risk (aOR 3.9, 95% CI 1.5-10.7).

CONCLUSION

Several RA-associated factors may contribute to increased TB risk in biologic-naïve patients with RA, making the risk of TB activation difficult to predict in the individual patient. To further decrease TB in patients with RA, the results suggest that screening for latent TB should also be considered in biologic-naïve patients.

The Interplay Between Systemic Inflammation, Oxidative Stress, and Tissue Remodeling in Tuberculosis

Significance: Excessive and prolonged proinflammatory responses are associated with oxidative stress, which is commonly observed during chronic tuberculosis (TB). Such condition favors tissue destruction and consequently bacterial spread. A tissue remodeling program is also triggered in chronically inflamed sites, facilitating a wide spectrum of clinical manifestations. Recent Advances: Since persistent and exacerbated oxidative stress responses have been associated with severe pathology, a number of studies have suggested that the inhibition of this augmented stress response by improving host antioxidant status may represent a reasonable strategy to ameliorate tissue damage in TB. Critical Issues: This review summarizes the interplay between oxidative stress, systemic inflammation and tissue remodeling, and its consequences in promoting TB disease. We emphasize the most important mechanisms associated with stress responses that contribute to the progression of TB. We also point out important host immune components that may influence the exacerbation of cellular stress and the subsequent tissue injury. Future Directions: Further research should reveal valuable targets for host-directed therapy of TB, preventing development of severe immunopathology and disease progression. Antioxid. Redox Signal. 34, 471-485.

Infliximab Can Improve Traumatic Brain Injury by Suppressing the Tumor Necrosis Factor Alpha Pathway

Traumatic brain injury (TBI) has both high morbidity and mortality rates and can negatively influence physical and mental health, while also causing extreme burden to both individual and society. Hitherto, there is no effective treatment for TBI because of the complexity of the brain anatomy and physiology. Currently, management strategies mainly focus on controlling inflammation after TBI. Tumor necrotizing factor alpha (TNF-α) plays a crucial role in neuroinflammation post-TBI. TNF-α acts as the initiator of downstream inflammatory signaling pathways, and its activation can trigger a series of inflammatory reactions. Infliximab is a monoclonal anti-TNF-α antibody that reduces inflammation. Herein, we review the latest findings pertaining to the role of TNF-α and infliximab in TBI. We seek to present a comprehensive clinical application prospect of infliximab in TBI and, thus, discuss potential strategies of infliximab in treating TBI.

Tuberculosis and TNF-α inhibitors in children: how to manage a fine balance

Since the introduction of biologic response modifiers (BRMs) in the management of children affected by the immune-mediated inflammatory disease, these patients substantially improved their quality of life. BRMs are generally well tolerated and effective in most children and adolescents refractory to conventional immunosuppressive therapy. On the other hand, patients receiving BRMs, especially TNF-α inhibitors, display an increased risk of primary infections or reactivations, i.e. due to Mycobacterium tuberculosis. M. tuberculosis can cause severe disease with consequent short- and long-term morbidity in children on anti-TNF-α treatment. The present paper analyses the increased risk of reactivation of latent tuberculosis infection (LTBI) or de novo TB infection in children treated with TNF-α inhibitors, with the purpose to provide recommendations for screening strategies and safety monitoring of paediatric patients. Special attention is also given to the currently available TB screening tools (IGRAs and TST) and their utility in the diagnosis of LTBI before starting the biologic therapy and during the treatment. Finally, the paper analyses the suggested TB-preventing therapies to adopt in these children and the correct timing to overlap anti-TB and anti-TNF-a treatment.

CD3+ Macrophages Deliver Proinflammatory Cytokines by a CD3- and Transmembrane TNF-Dependent Pathway and Are Increased at the BCG-Infection Site

Macrophages are essential cells of the innate immune response against microbial infections, and they have the ability to adapt under both pro- and anti-inflammatory conditions and develop different functions. A growing body of evidence regarding a novel macrophage subpopulation that expresses CD3 has recently emerged. Here, we explain that human circulating monocytes can be differentiated into CD3⁺TCRαβ⁺ and CD3⁺TCRαβ⁻ macrophages. Both cell subpopulations express on their cell surface HLA family molecules, but only the CD3⁺TCRαβ⁺ macrophage subpopulation co-express CD1 family molecules and transmembrane TNF (tmTNF). CD3⁺TCRαβ⁺ macrophages secrete IL-1β, IL-6 IP-10, and MCP-1 by both tmTNF- and CD3-dependent pathways, while CD3⁺TCRαβ⁻ macrophages specifically produce IFN-γ, TNF, and MIP-1β by a CD3-dependent pathway. In this study, we also used a mouse model of BCG-induced pleurisy and demonstrated that CD3⁺ myeloid cells (TCRαβ⁺ and TCRαβ⁻ cells) are increased at the infection sites during the acute phase (2 weeks post-infection). Interestingly, cell increment was mediated by tmTNF, and the soluble form of TNF was dispensable. BCG-infection also induced the expression of TNF receptor 2 on CD3⁺ myeloid cells, which increased after BCG-infection, suggesting that the tmTNF/TNFRs axis plays an important role in the presence or function of these cells in tuberculosis.

Modelling Bovine Granuloma Formation In Vitro upon Infection with Mycobacterium Avium Subspecies Paratuberculosis

Mycobacterium avium subspecies paratuberculosis (Map) causes chronic granulomatous disease in cattle and ruminant livestock, causing substantial economic losses. Current vaccines delay clinical signs but cannot train the immune system to fully eradicate latent Map. During latency, Map uses host defenses, cage-like macrophage clusters called granuloma, as incubators for months or years. We used an in vitro model to investigate the early coordination of macrophages into granuloma upon Map infection over ten days. We found that at multiplicities of infection (MOI; Map:macrophages) of 1:2 and below, the macrophages readily form clusters and evolve pro-inflammatory cytokines in keeping with a cell-mediated immune response. At higher MOIs, viability of host macrophages is negatively impacted. At 1:4 MOI, we quantified viable Map in our model and confirmed that intracellular Map reproduced over the first five days of infection. Host cells expressed Type 1-specific cytokines, and Map-infected macrophages displayed reduced motility compared to Map-exposed, uninfected macrophages, suggesting an important role for uninfected macrophages in the early aggregative response. Reported is the first in vitro JD granuloma model capturing Map and macrophage viability, size distribution of resulting clusters, motility of monocyte-derived macrophages, and cytokine response during clustering, allowing quantitative analysis of multiple parameters of the Map-specific granulomatous response.

The use of biologics for autoimmune rheumatic diseases in fertility and pregnancy

In an age where autoimmune rheumatic diseases are successfully managed with biologics, their discontinuation in pregnancy is inadvisable without careful forethought; maternal disease activity is associated with adverse pregnancy outcomes, which has long-term implications for both mother and offspring. We aim to provide clinicians with the necessary tools to facilitate decision-making - when a biologic should be used, when it can be discontinued in pregnancy if appropriate. The pathophysiology of these biologic molecules and their effect on fertility, pregnancy and parturition are discussed. A summary of the 2016 international guidelines (European League Against Rheumatism and British Society in Rheumatology) on biologics in pregnancy has been tabulated; more recent publications are discussed in depth. Data on transplacental-transfer ratios and breastmilk excretion rates are also included. Biologic effects on organogenesis, their implications for the exposed infant in terms of infection risks and vaccination requirements are included, and future directions for research proposed.

Th1, Th17, and Treg Responses are Differently Modulated by TNF-α Inhibitors and Methotrexate in Psoriasis Patients

Psoriasis is a chronic, recurrent, immune-mediated, hyperproliferative inflammatory skin disease. The role of the adaptive immune system, particularly of Th1 and Th17 lymphocytes, has been regarded as prominent in the immunopathogenesis of psoriasis, as well as decreased Tregs function. Immunobiological drugs were administered in therapeutic pulses and a few studies evaluate their effects on the immune repertoire. The aim of this study was to evaluate the adaptive immune profile of patients with severe psoriasis under immunobiological treatment in two time points. Thirty-two psoriasis patients and 10 control patients were evaluated. In the group of psoriasis patients, 10 patients were on anti-TNF and 14 patients on methotrexate treatment, while 8 individuals were not treated. IL-17, IFN-γ, TNF-α, IL-6, IL-2, and IL-10 were analyzed. CD4 T cell intracellular cytokines were analyzed. It was observed that stimulation could significantly increase the production of IL-17, IFN-γ, TNF-α, and IL-10 only before anti-TNF pulse therapy. The activation of Th1 and Treg cells after stimulation was significantly higher before anti-TNF pulse. Patients on methotrexate or anti-TNF therapy produced significantly lower levels of TNF-α, IL-10, and IL-6. Furthermore, these patients showed a significant decrease in the activated CD4+ T cells. The treatment with immunomodulator or methotrexate modulates the activation of CD4+ T cells, and anti-TNF treatment appears to have a modulating effect on the activation and production of Th1, Th17, and Treg cells.

Simultaneous Adalimumab and Antitubercular Treatment for Latent Tubercular Infection: An Experience from Nepal

Introduction

In Nepal, adalimumab is the most common agent being used, but in a disease activity-based dose tapering to address the economic constraints. Another constraint is the high risk of reactivation of tuberculosis in countries with high burden, especially with the use of tumor necrosis factor blocking agents. Though there are recommendations for screening and treatment of latent tuberculosis infection (LTBI) before using adalimumab, data is not clear regarding the appropriate screening schedule and the timing of initiation of biologic therapy.

Methodology

This retrospective review of prospectively followed cohort of spondyloarthropathy patients aimed to evaluate the efficacy of simultaneous initiation of adalimumab with LTBI treatment. Patients fulfilling either the modified New York criteria for ankylosing spondylitis or Assessment in SpondyloArthritis international Society criteria and who were refractory to oral treatment were screened with Mantoux (≥10mm) and interferon gamma release assay (QuantiFERON) to detected LTBI. Those who tested positive were started on rifampicin/isoniazid combination for 3 months and adalimumab treatment on the same day. The patients were followed up at 2 weeks, 4 weeks, 12 weeks, and then every 3 months for 2 years.

Results

Out of 784 patients diagnosed, 92 were receiving adalimumab. LTBI was detected by positivity of either Mantoux or QuantiFERON in 29.3% patients. None of the patients with LTBI who were started on the 2 drug regime simultaneous with adalimumab developed activation of tuberculosis. However, two patients testing negative for both the tests developed tubercular pleural effusion during treatment.

Conclusions

Our findings indicate that screening for LTBI should be more frequent in patients from high tuberculosis burden countries; treatment of LTBI with rifampicin/isoniazid combination for 3 months is effective in preventing reactivation even when adalimumab is started simultaneously.

Comparative Study of the Molecular Basis of Pathogenicity of M. bovis Strains in a Mouse Model

It is widely accepted that different strains of Mycobacterium tuberculosis have variable degrees of pathogenicity and induce different immune responses in infected hosts. Similarly, different strains of Mycobacterium bovis have been identified but there is a lack of information regarding the degree of pathogenicity of these strains and their ability to provoke host immune responses. Therefore, in the current study, we used a mouse model to evaluate various factors involved in the severity of disease progression and the induction of immune responses by two strains of M. bovis isolated from cattle. Mice were infected with both strains of M. bovis at different colony-forming unit (CFU) via inhalation. Gross and histological findings revealed more severe lesions in the lung and spleen of mice infected with M. bovis N strain than those infected with M. bovis C68004 strain. In addition, high levels of interferon-γ (IFN-γ), interleukin-17 (IL-17), and IL-22 production were observed in the serum samples of mice infected with M. bovis N strain. Comparative genomic analysis showed the existence of 750 single nucleotide polymorphisms and 145 small insertions/deletions between the two strains. After matching with the Virulence Factors Database, mutations were found in 29 genes, which relate to 17 virulence factors. Moreover, we found an increased number of virulent factors in M. bovis N strain as compared to M. bovis C68004 strain. Taken together, our data reveal that variation in the level of pathogenicity is due to the mutation in the virulence factors of M. bovis N strain. Therefore, a better understanding of the mechanisms of mutation in the virulence factors will ultimately contribute to the development of new strategies for the control of M. bovis infection.

Human Monocytic Suppressive Cells Promote Replication of Mycobacterium tuberculosis and Alter Stability of in vitro Generated Granulomas

Tuberculosis (TB) has tremendous public health relevance. It most frequently affects the lung and is characterized by the development of unique tissue lesions, termed granulomas. These lesions encompass various immune populations, with macrophages being most extensively investigated. Myeloid derived suppressor cells (MDSCs) have been recently identified in TB patients, both in the circulation and at the site of infection, however their interactions with Mycobacterium tuberculosis (Mtb) and their impact on granulomas remain undefined. We generated human monocytic MDSCs and observed that their suppressive capacities are retained upon Mtb infection. We employed an in vitro granuloma model, which mimics human TB lesions to some extent, with the aim of analyzing the roles of MDSCs within granulomas. MDSCs altered the structure of and affected bacterial containment within granuloma-like structures. These effects were partly controlled through highly abundant secreted IL-10. Compared to macrophages, MDSCs activated primarily the NF-κB and MAPK pathways and the latter largely contributed to the release of IL-10 and replication of bacteria within in vitro generated granulomas. Moreover, MDSCs upregulated PD-L1 and suppressed proliferation of lymphocytes, albeit with negligible effects on Mtb replication. Further comprehensive characterization of MDSCs in TB will contribute to a better understanding of disease pathogenesis and facilitate the design of novel immune-based interventions for this deadly infection.