Therapeutic Potential of IL-17-Mediated Signaling Pathway in Autoimmune Liver Diseases

FGF4 improves hepatocytes ferroptosis in autoimmune hepatitis mice via activation of CISD3

Autoimmune hepatitis (AIH) is increasingly affecting human health but pharmacotherapies remain to be identified. Growing evidence reveals that ferroptosis, a newly recognized form of programmed cell death, is critical for AIH. However, the exact mechanisms of the ferroptotic cascade remain elusive. Data in this study showed that ferroptosis aggravation was associated with protectively-elevated fibroblast growth factor 4 (FGF4) expression in Concanavalin A (ConA)-induced AIH liver injury, with these effects being effectively reversed by Ferrostatin-1 (Fer-1). Moreover, hepatic Fgf4 depletion was more susceptible to lipid peroxidation and iron accumulation, as well as hepatic lesion and inflammation caused by ConA administration. Conversely, treatment with non-mitogenic recombinant FGF4 (rFGF4) mitigated liver damage and hepatocellular ferroptosis while being accompanied by the upregulation of CDGSH iron-sulfur domain-containing protein 3 (CISD3) in vivo and in vitro. Furthermore, CISD3 overexpression exhibited stronger resistance to ferroptosis while CISD3 knockdown reduced ferroptotic biomarkers cystine/glutamate transporter (xCT) and glutathione peroxidase 4（GPX4) in rFGF4-treated Erastin-induced AML12 cells. In addition, rFGF4 significantly enhanced the levels of heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) in ConA-induced AIH mice. Overall, this study showed that FGF4 can act as a phylactic role in AIH progression, with rFGF4 treatment inhibiting ferroptosis of hepatocytes by increasing CISD3 levels and activating Nrf2/HO-1 signaling.

A pilot study of vidofludimus calcium for treatment of primary sclerosing cholangitis

The purpose of this pilot study was to explore the efficacy, safety, and tolerability of vidofludimus calcium (VC) in the treatment of primary sclerosing cholangitis (PSC). This was a single-arm open-label pilot study with a cohort of 18 patients with PSC. Study patients received VC for a period of 6 months. The study was undertaken at two sites, Mayo Clinic, Rochester, MN, and Mayo Clinic, Phoenix, AZ. The primary endpoint of the study was improvement of serum alkaline phosphatase (ALP) at the end of the study. Secondary endpoints included assessment of other liver biomarkers (bilirubin, alanine aminotransferase, and aspartate aminotransferase). Of 18 patients enrolled, 11 completed the 6 months of study treatment. Patients who completed treatment versus those who did not were similar other than a significantly higher direct bilirubin at baseline in the group that completed treatment (mean ± SD, 0.4 ± 0.3 versus 0.1 ± 0.1, p = 0.04). By intent to treat analysis, the primary outcome was met in 16.7% (3/18) of patients. By per-protocol analysis, including only patients who completed treatment, normalization of ALP occurred in 27.7% (3/11) at week 24 (95% confidence interval, 6.0% to 61.0%). VC was well tolerated with no drug-related serious adverse events. Conclusion: This proof of concept study provides support for further exploration of VC in patients with PSC.

Biological therapies in patients with liver disease: are they really lifesavers?

INTRODUCTION

The liver plays a key role in the setting of immune tolerance. Targeting antigens for presentation by antigen-presenting cells in the liver can induce immune tolerance to either autoantigens from the liver itself or organs outside of the liver. Despite its non-conventional capacity for tolerance induction, the liver remains a target organ for autoimmune diseases. Whereas chronic inflammation and intra-hepatic immuno-suppressive microenvironment occurring during liver fibrosis lead to hepatocellular carcinoma. Monoclonal antibodies have revolutionized the therapeutic strategies of many autoimmune diseases and some cancers.

AREAS COVERED

We review data from literature regarding the safety and efficacy of biologics in treating hepatobiliary autoimmune diseases and primary liver cancers. Furthermore, we describe their potential use in the setting of liver transplants and their main immune-related liver adverse events.

EXPERT OPINION

Biological therapies have changed the natural history of main autoimmune diseases and solid cancers. Compared to other organs and disease settings, the liver lags behind in biologics and their applications. The development of novel diagnostic and therapeutic strategies based on the immunological and antigenic characteristics of the hepatobiliary system could reduce mortality and transplant rates linked to chronic liver diseases.

Comparative Transcriptomic Analysis Reveals the Immunosuppressive Targets of Mesalazine in Dextran Sulfate Sodium-Induced Ulcerative Colitis

Ulcerative colitis (UC) is a complex inflammatory bowel disorder that can induce colonic and rectal dysfunction. Mesalazine, a first-line medicine, is routinely prescribed for UC treatment. However, the pharmacological targets of mesalazine against UC are not detailed in current publications. In the current study, a transcriptomics strategy was applied to reveal the therapeutic targets and molecular mechanisms of mesalazine for treating dextran sulfate sodium (DSS)-induced UC in mice. Compared with the UC group, a total of 1,663 differentially expressed genes were identified in mesalazine-treated mice, of which 262 were upregulated and 1,401 were downregulated. GO and KEGG enrichment analyses indicated that the protective actions of mesalazine for treating UC were related to the functional regulation of immune inflammatory response, such as the regulation of T cells, white blood cells, and cytokine receptor pathways. In addition, ingenuity pathway analysis of the gene network further revealed the inhibitory action of mesalazine on C-C motif chemokine ligands (CCL11 and CCL21) and C-X-C motif chemokine ligands (CXCL3 and CXCR2). Taken together, the current transcriptomic findings revealed anti-UC pharmacological targets, including the newly discovered biotargets CCL11, CCL21, CXCL3, and CXCR2, of mesalazine against DSS-induced intestinal inflammation.

The expression and clinical significance of serum IL-17 in patients with primary biliary cirrhosis

Background

We aimed to investigate the expression and clinical significance of interleukin 17 (IL-17) in patients with primary biliary cirrhosis (PBC).

Methods

PBC patients (n=127), patients without PBC (n=100) were selected from January 2015 to December 2015.The measure of IL-17 level was performed by cytometric beads array (CBA), immunohistochemistry and real-time PCR (QRT-PCR).

Results

The expression levels of serum IL-17, IL-6, IFN-γ, TNF-α and IL-10 in PBC groups were significantly higher than control group, a positively correlation between IL-17 and ALT, ALP, GGT, CIV was observed in PBC patients (r=0.350, P=0.013; r=0.373, P=0.008; r=0.337, P=0.017; r=0.349, P=0.021). In addition, IL-17 mRNA expression level in PBC group was higher than control group. Immunohistochemical results suggest that positive cells did not appear in normal tissues, while they appeared in the PBC liver tissue, mainly in the bile duct.

Conclusions

This study shows that IL-17 over expressed in PBC patients, it played a pro-inflammatory effect in the pathogenesis of PBC, most probably as a targeting drug research.

High-throughput chinmedomics strategy for discovering the quality-markers and potential targets for Yinchenhao decoction

BACKGROUND

Yinchenhao decoction (YCHD) has been widely applied in the clinic for various kinds of liver disease, especially for the therapy of dampness-heat jaundice syndrome (DHJS). Some studies have investigated the pharmacological activity and compositions of YCHD. However, its Q-markers and the action targets are still unrevealed.

PURPOSE

This work aims to clarify the therapeutic effect of YCHD against DHJS and discover the quality-markers (Q-markers) of YCHD based on the high-throughput chinmedomics strategy and then predict the potential targets and action mechanism of YCHD against DHJS.

METHODS

Ultra-high performance liquid chromatography/mass spectrometry (UPLC-MS) combined with pattern recognition method was utilized to analyze serum samples and urine samples. Multivariate data analysis and network pharmacology technology were used to identify the effective components and biomarkers associated with therapeutic effects.

RESULTS

With the high sensitivity UPLC-MS technology, a total of 69 compounds from YCHD were identified and 41 of them were absorbed in blood. Besides, 34 urine biomarkers from DHJS were identified. Of note, we utilized chinmedomics technology on the correlation analysis of urine biomarkers and absorbed components to determine 9 core-compounds as the Q-markers responsible for the efficacy of YCHD. Finally, a total of 12 potential targets were discovered.

CONCLUSION

This work provides a powerful method for clarifying the efficacy of TCM and discovering the effective ingredients as Q-markers.

Novel Diagnostic and Therapeutic Strategies in Juvenile Autoimmune Hepatitis

Juvenile autoimmune hepatitis (JAIH) is a rare, chronic, inflammatory disease of the liver characterized by a complex interaction between genetic, immunological, and environmental factors leading to loss of immunotolerance to hepatic antigens. It affects both children and adolescents, most commonly females, and its clinical manifestations are quite variable. JAIH is progressive in nature and if left untreated may lead to cirrhosis and terminal liver failure. Although JAIH was first described almost 50 years ago, there have been few significant advances in the clinical management of these patients, both in terms of available diagnostic tools and therapeutic options. Aminotransferase activity, class G immunoglobulins and autoantibodies are the biomarkers used to diagnose AIH and monitor treatment response alongside clinical and histological findings. Despite their utility and cost-effectiveness, these biomarkers are neither an accurate expression of AIH pathogenic mechanism nor a precise measure of treatment response. Current standard of care is mainly based on the administration of steroids and azathioprine. This combination of drugs has been proven effective in inducing remission of disease in the majority of patients dramatically improving their survival; however, it not only fails to restore tolerance to hepatic autoantigens, but it also does not halt disease progression in some patients, it is often needed life-long and finally, it has deleterious side-effects. The ideal therapy should be enough selective to contrast immune-mediated live damage while preserving or potentiating the ability to develop permanent tolerance vs. pathogenic autoantigens. By reviewing the state of the art literature, this article highlights novel diagnostic and therapeutic strategies for managing pediatric AIH with a special focus on new strategies of immunotherapy. These promising tools could improve the diagnostic algorithm, more accurately predict disease prognosis, and provide targeted, individualized treatment.

Bone marrow derived-mesenchymal stem cells downregulate IL17A dependent IL6/STAT3 signaling pathway in CCl4-induced rat liver fibrosis

Therapeutic potential of bone marrow–derived mesenchymal stem cells (BM-MSCs) has been reported in several animal models of liver fibrosis. Interleukin (IL) 17A, IL6 and Stat3 have been described to play crucial roles in chronic liver injury. However, the modulatory effect of MSCs on these markers was controversial in different diseases. BM-MSCs might activate the IL6/STAT3 signaling pathway and promote cell invasion in hepatocellular carcinoma, but the immunomodulatory role of BM-MSCs on IL17A/IL6/STAT3 was not fully elucidated in liver fibrosis. In the present study, we evaluated the capacity of the BM-MSCs in the modulation of cytokines milieu and signal transducers, based on unique inflammatory genes Il17a and Il17f and their receptors Il17rc and their effect on the IL6/STAT3 pathway in CCl₄-induced liver fibrosis in rats. A single dose of BM-MSCs was administered to the group with induced liver fibrosis, and the genes and proteins of interest were evaluated along six weeks after treatment. Our results showed a significant downregulation of Il17a, Il17ra, il17f and Il17rc genes. In accordance, BM-MSCs administration declined IL17, IL2 and IL6 serum proteins and downregulated IL17A and IL17RA proteins in liver tissue. Interestingly, BM-MSCs downregulated both Stat3 mRNA expression and p-STAT3, while Stat5a gene was downregulated and p-STAT5 protein was elevated. Also P-SMAD3 and TGFβR2 proteins were downregulated in response to BM-MSCs treatment. Collectively, we suggest that BM-MSCs might play an immunomodulatory role in the treatment of liver fibrosis through downregulation of IL17A affecting IL6/STAT3 signaling pathway.

MAIT cells are chronically activated in patients with autoimmune liver disease and promote profibrogenic hepatic stellate cell activation

Autoimmune liver diseases (AILDs) are chronic liver pathologies characterized by fibrosis and cirrhosis due to immune-mediated liver damage. In this study, we addressed the question whether mucosal-associated invariant T (MAIT) cells, innate-like T cells, are functionally altered in patients with AILD and whether MAIT cells can promote liver fibrosis through activation of hepatic stellate cells (HSCs). We analyzed the phenotype and function of MAIT cells from AILD patients and healthy controls by multicolor flow cytometry and investigated the interaction between human MAIT cells and primary human hepatic stellate cells (hHSCs). We show that MAIT cells are significantly decreased in peripheral blood and liver tissue of patients with AILD. Notably, MAIT cell frequency tended to decrease with increasing fibrosis stage. MAIT cells from AILD patients showed signs of exhaustion, such as impaired interferon-γ (IFN-γ) production and high ex vivo expression of the activation and exhaustion markers CD38, HLA-DR, and CTLA-4. Mechanistically, this exhausted state could be induced by repetitive stimulation of MAIT cells with the cytokines interleukin (IL)-12 and IL-18, leading to decreased IFN-γ and increased exhaustion marker expression. Of note, repetitive stimulation with IL-12 further resulted in expression of the profibrogenic cytokine IL-17A by otherwise exhausted MAIT cells. Accordingly, MAIT cells from both healthy controls and AILD patients were able to induce an activated, proinflammatory and profibrogenic phenotype in hHSCs in vitro that was partly mediated by IL-17.

CONCLUSION

Our data provide evidence that MAIT cells in AILD patients have evolved towards an exhausted, profibrogenic phenotype and can contribute to the development of HSC-mediated liver fibrosis. These findings reveal a cellular and molecular pathway for fibrosis development in AILD that could be exploited for antifibrotic therapy. (Hepatology 2018;68:172-186).

Serum Levels of IL-33 and Correlation with IL-4, IL-17A, and Hypergammaglobulinemia in Patients with Autoimmune Hepatitis

This study investigated the role of IL-33 in the pathogenesis of autoimmune hepatitis (AIH). The levels of IL-33/sST2 and Th1/Th2/Th17-type cytokines were determined by enzyme-linked immunosorbent assay in serum samples obtained from 30 AIH patients and 20 healthy controls (HCs). In addition, a murine model of experimental AIH (EAIH) was established to investigate the role of IL-33 in disease progression. The serum levels of IL-33, sST2, Th17 cytokines (IL-17A), Th1 cytokines (IFN-γ, TNF-α), and Th2 cytokines (IL-4) were significantly elevated in AIH patients compared to HCs. Following immunosuppression therapy, serum levels of IL-33 and sST2 were significantly decreased. Additionally, the serum levels of IL-33 in AIH patients were correlated positively with markers of hypergammaglobulinemia (IgG, IgM, and IgA) and liver injury (γ-GT/ALP). Also, the serum levels of IL-33 in AIH patients were correlated positively with proinflammatory cytokine levels (IL-17A and IL-4). Interestingly, treatment of EAIH mice with a specific IL-33 neutralizing antibody significantly reversed the increasing trend in serum ALT/AST and inhibited the production of the type 2 (IL-4) and type 17 cytokines (IL-17) but not the type 1 cytokine (IFN-γ). Our findings highlight the possible role of the IL-33/sST2 axis in the progression of AIH, opening a new door for developing a novel therapeutic strategy for AIH.

Immune Dysregulation in Cancer Patients Undergoing Immune Checkpoint Inhibitor Treatment and Potential Predictive Strategies for Future Clinical Practice

Realization of the full potential of immune checkpoint inhibitor-targeted onco-immunotherapy is largely dependent on overcoming the obstacles presented by the resistance of some cancers, as well as on reducing the high frequency of immune-related adverse events (IRAEs) associated with this type of immunotherapy. With the exception of combining therapeutic monoclonal antibodies, which target different types of immune checkpoint inhibitory molecules, progress in respect of improving therapeutic efficacy has been somewhat limited to date. Likewise, the identification of strategies to predict and monitor the development of IRAEs has also met with limited success due, at least in part, to lack of insight into mechanisms of immunopathogenesis. Accordingly, considerable effort is currently being devoted to the identification and evaluation of strategies which address both of these concerns and it is these issues which represent the major focus of the current review, particularly those which may be predictive of development of IRAEs. Following an introductory section, this review briefly covers those immune checkpoint inhibitors currently approved for clinical application, as well as more recently identified immune checkpoint inhibitory molecules, which may serve as future therapeutic targets. The remaining and more extensive sections represent overviews of: (i) putative strategies which may improve the therapeutic efficacy of immune checkpoint inhibitors; (ii) recent insights into the immunopathogenesis of IRAEs, most prominently enterocolitis; and (iii) strategies, mostly unexplored, which may be predictive of development of IRAEs.

Liver Illness and Psoriatic Patients

Psoriasis is a chronic inflammatory disease of the skin affecting approximately 2% of the world's population. Systemic treatments, including methotrexate and cyclosporin, are associated with potential hepatotoxicity, due to either direct liver damage or immunosuppression or both immunomediated and a direct liver injury; therefore, treatment of patients with psoriasis poses a therapeutic challenge. The aim of this minireview is to help clinicians in the management of psoriatic patients who develop signs of liver dysfunction. To find relevant articles, a comprehensive search was performed on PubMed, EMBASE, and Cochrane with appropriate combinations of the following keywords being considered: viral hepatitis, nonalcoholic fatty liver disease, psoriasis, hepatotoxicity, drug toxicity, cholestasis, and autoimmune liver diseases.

Implication of increased serum stromal cell-derived factor-1 for primary biliary cholangitis

BACKGROUND

Stromal cell-derived factor-1 (SDF-1), also called chemokine (C-X-C motif) ligand 12 (CXCL12), as a chemokine for premature B cells, T cells and monocytes, is detected in liver, pancreas, spleen and heart. However, its diagnostic value for primary biliary cholangitis (PBC) as well as the association of SDF-1 with inflammatory and fibrotic progression is unclear. The aim of this study was to determine serum stromal cell-derived factor-1 (SDF-1) level and to explore its diagnostic value for primary biliary cholangitis (PBC) as well as the association of SDF-1 with inflammatory and fibrotic progression of PBC.

METHODS

A total of 60 PBC patients who received liver biopsy, 32 age- and sex-matched patients with chronic hepatitis B (CHB) and 30 age- and sex-matched healthy controls (HC) were recruited. The sera were measured for SDF-1, interleukin-4 (IL-4), interferon gamma (IFN-γ) and IL-17 using multiplex immunoassay. PBC was divided into four histologic stages according to Scheuer's classification.

RESULTS

The results showed significantly higher median level of serum SDF-1 (median, interquartile (IQR), 1186.96, 1002.05-1471.33 pg/mL) in PBC patients than those with CHB (median, IQR, 740.69,600.30-1239.27 pg/mL) and HC (median, IQR, 738.44, 687.65-879.33 pg/mL) (P < 0.001). There was no significant difference between CHB patients and HC (P = 0.526). The receiver operating characteristic curves (ROC) showed good diagnostic performance of serum SDF-1 for PBC, AMA-positive and -negative PBC. In particular for AMA-negative PBC, the area under ROC was 0.817, with optimal cutoff value of 802.64 pg/mL and the sensitivity of 100%. Serum SDF-1 level was not associated with other immune, inflammatory and fibrotic indicators, including AMA, ANA, anti-gp210, sp100 and centromere antibodies, bilirubin, ALT, AST, ALP, GGT, WBC, neutrophil, lymphocyte, platelet, Neutrophil- (NLR) and platelet-lymphocyte (PLR), AST to ALT ratio, AST to platelet ratio index (APRI) and FIB-4 index (P > 0.05). Also, there was no significant difference for serum SDF-1 among histological stages (P = 0.091). However, Serum SDF-1 level was significantly correlated with serum IL-17 (r = 0.373, P = 0.004), but not with IL-4 (r = 0.110, P = 0.407) and IFN-γ (r = 0.215, P = 0.098) in those with PBC.

CONCLUSION

Serum SDF-1 is increased in and may be a potential useful marker for PBC. Moreover, it may be associated with Th17 recruitment and differentiation in PBC. However, serum SDF-1 may not be associated with the progression of PBC.

IL-17A blockade or deficiency does not affect progressive renal fibrosis following renal ischaemia reperfusion injury in mice

Objectives

IL-17A contributes to acute kidney injury and fibrosis. Therefore, we asked whether IL-17A deficiency or treatment with a IL-17A blocking antibody impacts severe renal ischaemia reperfusion injury (IRI) and the progression to chronic kidney disease (CKD).

Methods

IL-17A-deficient and wild-type (WT) mice underwent transient unilateral renal pedicle clamping for 45 min to induce IRI and subsequent renal fibrosis. Furthermore, a neutralizing anti-IL-17A antibody (mAb) was injected into WT mice before induction of renal IRI intravenously. On days 1, 7 and 21, inflammation, fibrosis, leukocyte infiltration and pro-inflammatory and pro-fibrotic cytokine expression were assessed in kidneys using histology, qPCR and flow cytometry.

Key findings

IL-17A was significantly increased after renal IRI in WT kidneys. Levels of pro-inflammatory (MCP-1) cytokine and pro-fibrotic (collagen 1α1, fibronectin) transcripts were similar in the experimental groups studied. IL-17A deficiency had no effect on renal T-cell influx or the number, inflammatory phenotype, or spatial distribution of macrophages. Similarly, administration of an IL-17A blocking antibody did not attenuate inflammation.

Conclusions

Despite the effects of IL-17 in other inflammation models, neither genetic IL-17A deficiency nor treatment with an IL-17A blocking antibody attenuated IRI and progression to CKD. We conclude that in severe renal IRI IL-17A is not crucially involved in disease progression.

Psoriatic inflammation causes hepatic inflammation with concomitant dysregulation in hepatic metabolism via IL-17A/IL-17 receptor signaling in a murine model

Psoriatic inflammation has been shown to be associated with cardiovascular dysfunction and systemic inflammation. Recently, psoriasis has also been linked to hepatic disorders, however underlying mechanism connecting the two are unknown. IL-17A being a central pro-inflammatory cytokine in the pathogenesis of psoriasis may be involved in hepatic inflammation through its receptor and downward signaling; however so far no study has investigated IL-17A related signaling in the liver during psoriasis in a murine model. Therefore, this study explored psoriasis-induced hepatic inflammation and concurrent metabolic changes. Mice were applied topically imiquimod (IMQ) to develop psoriatic inflammation. Additionally mice were also treated either with IL-17A or anti-IL17A antibody to explore the role of IL-17 related signaling in liver. Mice were then assessed for hepatic inflammation through assessment of inflammatory/oxidative stress markers (IL-17RC, NFκB, IL-6, MCP-1, IL-1β, GM-CSF, ICAM-1, iNOS, lipid peroxides and myeloperoxidase activity) as well as hepatic injury (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) and protein/lipid metabolic biomarkers (total proteins, albumin, total bilirubin, triglycerides, HDL cholesterol, and total cholesterol). IMQ treatment led to hepatic inflammation as evidenced by increased pro-inflammatory cytokines and oxidative stress with concomitant dysregulation in hepatic protein/lipid metabolism. Treatment with IL-17A further aggravated, whereas treatment with anti-IL17A antibody ameliorated IMQ-induced changes in hepatic injury/inflammation and protein/lipid metabolism. Our study shows for the first time that psoriatic inflammation leads to hepatic inflammation which results in dysregulated protein/lipid metabolism through IL-17RC/NFκB signaling. This could result in increased risk of cardiovascular dysfunction in patients with psoriasis.

The Immunogenetics of Autoimmune Cholestasis

The immune-mediated hepatobiliary diseases, primary biliary cirrhosis and primary sclerosing cholangitis are relatively rare, albeit and account for a significant amount of liver transplant activity and liver-related mortality globally. Precise disease mechanisms are yet to be described although a contributory role of genetic predisposition is firmly established. In addition to links with the major histocompatibility complex, a number of associations outside this region harbor additional loci which underscore the fundamental role of breaks in immune tolerance and mucosal immunogenicity in the pathogenesis of autoimmune biliary disease. We provide an overview of these key discoveries before discussing putative avenues of therapeutic exploitation based on existing findings.

Th1 and Th17 Cells in Tuberculosis: Protection, Pathology, and Biomarkers

The outcome of Mycobacterium tuberculosis (Mtb) infection ranges from a complete pathogen clearance through asymptomatic latent infection (LTBI) to active tuberculosis (TB) disease. It is now understood that LTBI and active TB represent a continuous spectrum of states with different degrees of pathogen “activity,” host pathology, and immune reactivity. Therefore, it is important to differentiate LTBI and active TB and identify active TB stages. CD4⁺ T cells play critical role during Mtb infection by mediating protection, contributing to inflammation, and regulating immune response. Th1 and Th17 cells are the main effector CD4⁺ T cells during TB. Th1 cells have been shown to contribute to TB protection by secreting IFN-γ and activating antimycobacterial action in macrophages. Th17 induce neutrophilic inflammation, mediate tissue damage, and thus have been implicated in TB pathology. In recent years new findings have accumulated that alter our view on the role of Th1 and Th17 cells during Mtb infection. This review discusses these new results and how they can be implemented for TB diagnosis and monitoring.