The link between IL-23 and Th17 cell-mediated immune pathologies

Immune system benefits of pulmonary rehabilitation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by pulmonary and systemic inflammation. Inflammatory mediators show relationships with shortness of breath, exercise intolerance and health related quality of life. Pulmonary rehabilitation (PR), a comprehensive education and exercise training programme, is the most effective therapy for COPD and is associated with reduced exacerbation and hospitalization rates and increased survival. Exercise training, the primary physiological intervention within PR, is known to exert a beneficial anti-inflammatory effect in health and chronic diseases. The question of this review article is whether exercise training can also make such a beneficial anti-inflammatory effect in COPD. Experimental studies using smoke exposure mice models suggest that the response of the immune system to exercise training is favourably anti-inflammatory. However, the evidence about the response of most known inflammatory mediators (C-reactive protein, tumour necrosis factor α, interleukin 6, interleukin 10) to exercise training in COPD patients is inconsistent, making it difficult to conclude whether regular exercise training has an anti-inflammatory effect in COPD. It is also unclear whether COPD patients with more persistent inflammation are a subgroup that would benefit more from hypothesized immunomodulatory effects of exercise training (i.e., personalized treatment). Nevertheless, it seems that PR combined with maintenance exercise training (i.e., lifestyle change) might be more beneficial in controlling inflammation and slowing disease progress in COPD patients, specifically in those with early stages of disease.

Cytokines in gingivitis and periodontitis: from pathogenesis to therapeutic targets

Chronic inflammatory processes in the oral mucosa and periodontitis are common disorders caused by microflora and microbial biofilms. These factors activate both the innate and adaptive immune systems, leading to the production of pro-inflammatory cytokines. Cytokines are known to play a crucial role in the pathogenesis of gingivitis and periodontitis and have been proposed as biomarkers for diagnosis and follow-up of these diseases. They can activate immune and stromal cells, leading to local inflammation and tissue damage. This damage can include destruction of the periodontal ligaments, gingiva, and alveolar bone. Studies have reported increased local levels of pro-inflammatory cytokines, such as interleukin-1beta (IL-1beta), tumor necrosis factor (TNF), IL-6, IL-17, and IL-23, in patients with periodontitis. In experimental models of periodontitis, TNF and the IL-23/IL-17 axis play a pivotal role in disease pathogenesis. Inactivation of these pro-inflammatory pathways through neutralizing antibodies, genetic engineering or IL-10 function has been demonstrated to reduce disease activity. This review discusses the role of cytokines in gingivitis and periodontitis, with particular emphasis on their role in mediating inflammation and tissue destruction. It also explores new therapeutic interventions that offer potential for research and clinical therapy in these chronic inflammatory diseases.

Blimp-1 and c-Maf regulate immune gene networks to protect against distinct pathways of pathobiont-induced colitis

Intestinal immune responses to microbes are controlled by the cytokine IL-10 to avoid immune pathology. Here, we use single-cell RNA sequencing of colon lamina propria leukocytes (LPLs) along with RNA-seq and ATAC-seq of purified CD4+ T cells to show that the transcription factors Blimp-1 (encoded by Prdm1) and c-Maf co-dominantly regulate Il10 while negatively regulating proinflammatory cytokines in effector T cells. Double-deficient Prdm1fl/flMaffl/flCd4Cre mice infected with Helicobacter hepaticus developed severe colitis with an increase in TH1/NK/ILC1 effector genes in LPLs, while Prdm1fl/flCd4Cre and Maffl/flCd4Cre mice exhibited moderate pathology and a less-marked type 1 effector response. LPLs from infected Maffl/flCd4Cre mice had increased type 17 responses with increased Il17a and Il22 expression and an increase in granulocytes and myeloid cell numbers, resulting in increased T cell-myeloid-neutrophil interactions. Genes over-expressed in human inflammatory bowel disease showed differential expression in LPLs from infected mice in the absence of Prdm1 or Maf, revealing potential mechanisms of human disease.

Colonic mucosal associated invariant T cells in Crohn's disease have a diverse and non-public T cell receptor beta chain repertoire

OBJECTIVES

Mucosal-Associated Invariant T (MAIT) cells are T cells with a semi-invariant T cell receptor (TCR), recognizing riboflavin precursors presented by a non-polymorphic MR1 molecule. As these precursors are produced by the gut microbiome, we characterized the frequency, phenotype and clonality of MAIT cells in human colons with and without Crohn's disease (CD).

METHODS

The transcriptome of MAIT cells sorted from blood and intestinal lamina propria cells from colectomy recipients were compared with other CD8+ T cells. Colon biopsies from an additional ten CD patients and ten healthy controls (HC) were analyzed by flow cytometry. TCR genes were sequenced from individual MAIT cells from these biopsies and compared with those of MAIT cells from autologous blood.

RESULTS

MAIT cells in the blood and colon showed a transcriptome distinct from other CD8 T cells, with more expression of the IL-23 receptor. MAIT cells were enriched in the colons of CD patients, with less NKG2D in inflamed versus uninflamed segments. Regardless of disease, most MAIT cells expressed integrin α4β7 in the colon but not in the blood, where they were enriched for α4β7 expression. TCR sequencing revealed heterogeneity in the colon and blood, with few public sequences associated with cohorts.

CONCLUSION

MAIT cells are enriched in the colons of CD patients and disproportionately express molecules (IL-23R, integrin α4β7) targeted by CD therapeutics, to suggest a pathogenic role for them in CD. Public TCR sequences were neither common nor sufficiently restricted to a cohort to suggest protective or pathogenic antigen-specificities.

Inferred Causal Mechanisms of Persistent FMDV Infection in Cattle from Differential Gene Expression in the Nasopharyngeal Mucosa

Foot-and-mouth disease virus (FMDV) can persistently infect pharyngeal epithelia in ruminants but not in pigs. Our previous studies demonstrated that persistent FMDV infection in cattle was associated with under-expression of several chemokines that recruit immune cells. This report focuses on the analysis of differentially expressed genes (DEG) identified during the transitional phase of infection, defined as the period when animals diverge between becoming carriers or terminators. During this phase, Th17-stimulating cytokines (IL6 and IL23A) and Th17-recruiting chemokines (CCL14 and CCL20) were upregulated in animals that were still infected (transitional carriers) compared to those that had recently cleared infection (terminators), whereas chemokines recruiting neutrophils and CD8+ T effector cells (CCL3 and ELR+CXCLs) were downregulated. Upregulated Th17-specific receptor, CCR6, and Th17-associated genes, CD146, MIR155, and ThPOK, suggested increased Th17 cell activity in transitional carriers. However, a complex interplay of the Th17 regulatory axis was indicated by non-significant upregulation of IL17A and downregulation of IL17F, two hallmarks of TH17 activity. Other DEG suggested that transitional carriers had upregulated aryl hydrocarbon receptor (AHR), non-canonical NFκB signaling, and downregulated canonical NFκB signaling. The results described herein provide novel insights into the mechanisms of establishment of FMDV persistence. Additionally, the fact that ruminants, unlike pigs, produce a large amount of AHR ligands suggests a plausible explanation of why FMDV persists in ruminants, but not in pigs.

Epigenetic modulation of selected immune response genes and altered functions of T lymphocytes and macrophages collectively contribute to autoimmune diabetes protection

We have previously demonstrated that weekly treatment of female prediabetic NOD mice with a low dose of the histone deacetylase inhibitor Trichostatin A (TSA) bestowed long-lasting, irreversible protection against autoimmune diabetes. Herein we show that drug treatment diminished the infiltration of the pancreas with CD4+, CD8+ T cells, and Ly-6C+ monocytes. Significantly, TSA administration selectively repressed the expression of a set of genes exaggerated during diabetes and constitutively expressed primarily in the spleen and rarely in the pancreas. These genes encode lymphokines, macrophage-associated determinants, and transcription factors. Although the copy numbers of many histone deacetylases increased during diabetes in the spleen and pancreas, only those upregulated in the spleen were rendered sensitive to repression by TSA treatment. Mitogen-activated T lymphocytes derived from drug-treated donors displayed diminished diabetogenic potential following transfer into immunodeficient NOD.scid mice. In the immunocompromised recipients, diabetes caused by the transfer of activated T lymphocytes from untreated diabetic mice was hampered by the co-transfer of highly purified splenic CD11b+Ly-6C+ macrophages from drug-treated mice. However, the transfer of CD11b+Ly-6C+ macrophages from drug-treated mice failed to block ongoing diabetes in wild-type NOD mice. These data demonstrate that the modified gene expression and functional alteration of T lymphocytes and macrophages collectively contribute to diabetes protection afforded by the histone modifier in female NOD mice.

Mycobacterium tuberculosis RpfE-Induced Prostaglandin E2 in Dendritic Cells Induces Th1/Th17 Cell Differentiation

Prostaglandin E2 (PGE2) is an important biological mediator involved in the defense against Mycobacterium tuberculosis (Mtb) infection. Currently, there are no reports on the mycobacterial components that regulate PGE2 production. Previously, we have reported that RpfE-treated dendritic cells (DCs) effectively expanded the Th1 and Th17 cell responses simultaneously; however, the mechanism underlying Th1 and Th17 cell differentiation is unclear. Here, we show that PGE2 produced by RpfE-activated DCs via the MAPK and cyclooxygenase 2 signaling pathways induces Th1 and Th17 cell responses mainly via the EP4 receptor. Furthermore, mice administered intranasally with PGE2 displayed RpfE-induced antigen-specific Th1 and Th17 responses with a significant reduction in bacterial load in the lungs. Furthermore, the addition of optimal PGE2 amount to IL-2-IL-6-IL-23p19-IL-1β was essential for promoting differentiation into Th1/Th17 cells with strong bactericidal activity. These results suggest that RpfE-matured DCs produce PGE2 that induces Th1 and Th17 cell differentiation with potent anti-mycobacterial activity.

Exercise-induced downregulation of serum interleukin-6 and tumor necrosis factor-alpha in Egyptian handball players

Muscles of candidates work at various grades of intensity during handball exercises according to the pace of exercise. The movement pattern involves large number of contractions, feints, dodges and numerous changes in movements, all of which are highly responsible for changes in trainer's organs, including the immune system. In this study, inflammatory mediators involving interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in serum of 18 Egyptian male handball players, selected from Tanta club handball under 21 year’s old team, were analyzed. The analysis was established on samples collected just before and immediately after intermediate reasonable exercise via enzyme linked immunosorbent assay (ELISA). Moreover, white blood cells (WBCs) count and other hematological markers including hemoglobin %, hematocrit value, and platelet count were assessed. Our results demonstrated a significant decrease in the levels of IL-6 and TNF-α after exercise compared to those before exercise. This was coupled with an increase in WBCs and platelets count. It is also noteworthy that there was a significant positive correlation between serum levels of IL-6 and TNF-α in the study subjects coupled with a significant negative correlation between IL-6 and WBCs after the exercise. Therefore, it is concluded that intermediate reasonable exercises result in decreased levels of IL-6 and TNF-α, which result in decreasing of the inflammation and help in healing and rapid recovery of muscles of the candidates.

Genetic and pharmacological inhibition of the nuclear receptor RORα regulates TH17 driven inflammatory disorders

Full development of IL-17 producing CD4+ T helper cells (TH17 cells) requires the transcriptional activity of both orphan nuclear receptors RORα and RORγt. However, RORα is considered functionally redundant to RORγt; therefore, the function and therapeutic value of RORα in TH17 cells is unclear. Here, using mouse models of autoimmune and chronic inflammation, we show that expression of RORα is required for TH17 cell pathogenicity. T-cell-specific deletion of RORα reduces the development of experimental autoimmune encephalomyelitis (EAE) and colitis. Reduced inflammation is associated with decreased TH17 cell development, lower expression of tissue-homing chemokine receptors and integrins, and increased frequencies of Foxp3+ T regulatory cells. Importantly, inhibition of RORα with a selective small molecule antagonist mostly phenocopies our genetic data, showing potent suppression of the in vivo development of both chronic/progressive and relapsing/remitting EAE, but with no effect on overall thymic cellularity. Furthermore, use of the RORα antagonist effectively inhibits human TH17 cell differentiation and memory cytokine secretion. Together, these data suggest that RORα functions independent of RORγt in programming TH17 pathogenicity and identifies RORα as a safer and more selective therapeutic target for the treatment of TH17-mediated autoimmunity.

Immune Signatures of Treatment-Resistant Schizophrenia: A FondaMental Academic Centers of Expertise for Schizophrenia (FACE-SZ) Study

Treatment-resistant schizophrenia (TRS) affects around 30% of patients with schizophrenia (SZ) resulting in poor functioning, relapses, and reduced quality of life. Convergent findings show that inflammation could contribute to resistance. We thus search for immune signatures of patients with TRS/ultra TRS (UTRS) in a sample of community-dwelling outpatients with SZ. In total, 195 stabilized SZ patients (mean age = 31.2 years, 73% male gender) were consecutively included in the network of the FondaMental Expert Centers for Schizophrenia in France and received a thorough clinical assessment. At inclusion, psychotic symptomatology was evaluated by the Positive and Negative Syndrome Scale (PANSS) for schizophrenia. Circulating serum/plasma levels of a large panel of markers reflecting the main inflammatory pathways were evaluated. TRS was defined by current treatment by clozapine (CLZ) and UTRS by current CLZ treatment + PANSS total score ≥ 70. The frequency of TRS and UTRS patients was, respectively, 20% and 7.7% and was defined using multivariable analysis elevated by high levels of interleukin (IL)-12/IL-23p40, IL-17A, IL-10, and beta 2 microglobulin (B2M) and IL-12/IL-23p40, IL-17A, IL-6, IL-10, IFNγ, and B2M, respectively. These observations suggest that resistance and ultra resistance to CLZ treatment are underpinned by pro-inflammatory molecules mainly belonging to the T helper 17 pathway, a finding making sense given the interplay between inflammation and antipsychotic treatment responses. If confirmed, our findings may allow us to consider IL-23/IL-17 pathway as a therapeutic target for patients with resistance to antipsychotics.

Th17 associated cytokines in sputum samples from patients with cystic fibrosis

Cystic fibrosis (CF) is a genetic disease leading to chronic bacterial airway infection and inflammation. T helper 17 (Th17) cells are identified by their production of interleukin (IL)-17A, which recruit neutrophils to the site of airway infection. IL-23 is an important inducer of IL-17 and IL-22 production. The aim of this study was to study the role of Th17 cells in CF airway infection by measuring the levels of Th17 associated cytokines in sputum from CF patients with or without airway infection and by comparison with non-CF-controls. In a cross-sectional screening study, cytokine levels were measured with a Th17 multiplex cytokine ELISA. Significantly lower levels of IL-17A and IL-23 were found in sputa from infected CF patients. The lowest levels of IL-17A were found in patients chronically infected with P. aeruginosa, which also had the lowest IL-17/IL-22 ratio, while children had a higher ratio. Children also had higher IL-23 levels than adults. IL-1ß and IL-10 were significantly lower in CF sputum compared to controls. Thus, in our study CF patients with chronic infections had a lower production of Th17 associated cytokines in sputum compared with non-infected CF patients and infected patient without CF.

Differential Th Cell-Related Immune Responses in Young Physically Active Men after an Endurance Effort

The participation of T cell subsets in the modulation of immunity in athletes triggered by maximal effort was investigated. In total, 80 physically active young men (range 16-20 years) were divided into 5 age groups: 16, 17, 18, 19, and 20 years old. They performed efficiency tests on mechanical treadmills until exhaustion. White blood cell (WBC) and lymphocyte (LYM) counts were determined, and the type 1 (Th1), type 2 (Th2) helper T cells, T helper 17 (Th17), and T regulatory (Treg) cell distribution and plasma levels of selected cytokines were analyzed. An increase in WBC and LYM counts after the test and in Th1 and Treg cells after the test and in recovery was observed. There were no changes in Th2 cells. An increase in interleukins (IL): IL-2 and IL-8 was observed. The IL-6 level was altered in all studied groups. IL-17A and interferon gamma (IFN-γ) levels were increased in all studied groups. The mechanism of differential T cell subset activation may be related to athletes' age. The novel findings of this study are the involvement of Th17 cells in post-effort immune responses and the participation of IL-6 in post-effort and the long-term biological effect of endurance effort.

Inflammatory and mitogenic signals drive interleukin 23 subunit alpha (IL23A) secretion independent of IL12B in intestinal epithelial cells

The heterodimeric cytokine interleukin-23 (IL-23 or IL23A/IL12B) is produced by dendritic cells and macrophages and promotes the proinflammatory and regenerative activities of T helper 17 (Th17) and innate lymphoid cells. A recent study has reported that IL-23 is also secreted by lung adenoma cells and generates an inflammatory and immune-suppressed stroma. Here, we observed that proinflammatory tumor necrosis factor (TNF)/NF-κB and mitogen-activated protein kinase (MAPK) signaling strongly induce IL23A expression in intestinal epithelial cells. Moreover, we identified a strong crosstalk between the NF-κB and MAPK/ERK kinase (MEK) pathways, involving the formation of a transcriptional enhancer complex consisting of proto-oncogene c-Jun (c-Jun), RELA proto-oncogene NF-κB subunit (RelA), RUNX family transcription factor 1 (RUNX1), and RUNX3. Collectively, these proteins induced IL23A secretion, confirmed by immunoprecipitation of endogenous IL23A from activated human colorectal cancer (CRC) cell culture supernatants. Interestingly, IL23A was likely secreted in a noncanonical form, as it was not detected by an ELISA specific for heterodimeric IL-23 likely because IL12B expression is absent in CRC cells. Given recent evidence that IL23A promotes tumor formation, we evaluated the efficacy of MAPK/NF-κB inhibitors in attenuating IL23A expression and found that the MEK inhibitor trametinib and BAY 11-7082 (an IKKα/IκB inhibitor) effectively inhibited IL23A in a subset of human CRC lines with mutant KRAS or BRAFV600E mutations. Together, these results indicate that proinflammatory and mitogenic signals dynamically regulate IL23A in epithelial cells. They further reveal its secretion in a noncanonical form independent of IL12B and that small-molecule inhibitors can attenuate IL23A secretion.

The role of the interleukin-23/Th17 pathway in cardiometabolic comorbidity associated with psoriasis

Alterations in the innate and adaptive immunity underpin psoriasis pathophysiology, with the Th17 cells subset now recognized as the fundamental cells in the key controlling pathway involved in its pathogenesis. Since psoriasis is a systemic disease with important comorbidity, further knowledge on the interleukin (IL)‐23/Th17 axis led to the hypothesis that there may be shared pathogenic pathways between primary skin disease and comorbidity. Psoriasis has been identified as a risk factor for cardiovascular and metabolic disease, and increasing evidence gives support to this epidemiological observation from the clinical‐pathologically field. As an example, increased levels of IL‐23 and IL‐23R have been found in human atherosclerotic plaque, and levels correlated with symptom duration and mortality. Also, upregulation of IL‐23/IL‐17 seems to play an important role in both myocardial damage and stroke, with interesting reports on deleterious effect neutralization after administration of related anti‐bodies in both associated conditions. In diabetic patients, increased levels of IL‐23/IL‐17 have also been observed and available data support a synergistic role of IL‐23/IL‐17 in β‐cells damage. In obesity, signs of an expansion of Th17 subset in adipose tissue have been reported, as well as elevated concentrations of IL‐23 in obese patients. In non‐alcoholic fatty liver disease, closely related to metabolic syndrome, but also in other mentioned cardiometabolic disorders, a predominance of IL‐23 and other related pro‐inflammatory factors has been identified as participating in their pathogenesis. Thus, the involvement of the IL‐23/Th17 axis in these shared psoriasis‐cardiometabolic pathogenic mechanisms is reviewed and discussed in the light of the existing preclinical and clinical evidence, including that from comorbid psoriasis patients.

PPARγ Deficiency in Carbon Nanotube-elicited Granulomatous Inflammation Promotes a Th17 Response to a Microbial Antigen

BACKGROUND

The pathological consequences of interaction between environmental carbon pollutants and microbial antigens have not been fully explored. We developed a murine model of multi-wall carbon nanotube (MWCNT)-elicited granulomatous disease which bears a striking resemblance to sarcoidosis, a human granulomatous disease. Because of reports describing lymphocyte reactivity to mycobacterial antigens in sarcoidosis patients, we hypothesized that addition of mycobacterial antigen (ESAT-6) to MWCNT might elicit activation in T cells.

METHODS

Macrophage-specific peroxisome-proliferator-activated receptor gamma (PPARγ) knock out (KO) mice were studied along with wild-type mice because our previous report indicated PPARγ deficiency in sarcoidosis alveolar macrophages. MWCNT+ESAT-6 were instilled into mice. Controls received vehicle (surfactant-PBS) or ESAT-6 and were evaluated 60 days post-instillation. As noted in our recent publication, lung tissues from PPARγ KO mice instilled with MWCNT+ESAT-6 yielded more intensive pathophysiology, with elevated fibrosis.

RESULTS

Inspection of mediastinal lymph nodes (MLN) revealed no granulomas but deposition of MWCNT. MLN cell counts were higher in PPARγ KO than in wild-type instilled with MWCNT+ESAT-6. Moreover, the CD4:CD8 T cell ratio, a major clinical metric for human disease, was increased in PPARγ KO mice. Bronchoalveolar lavage (BAL) cells from PPARγ KO mice instilled with MWCNT+ESAT-6 displayed increased Th17 cell markers (RORγt, IL-17A, CCR6) which associate with elevated fibrosis.

CONCLUSION

These findings suggest that PPARγ deficiency in macrophages may promote ESAT-6-associated T cell activation in the lung, and that the MWCNT+ESAT-6 model may offer new insights into pathways of lymphocyte-mediated sarcoidosis histopathology.

Inflammatory bowel disease pathobiology: the role of the interferon signature

The pathogenesis of inflammatory bowel disease (IBD) is still unclear, but includes both inflammatory and autoimmune reactions. Current methodological approaches could better elucidate the cytokine pathways and the genetics involved in the etiopathogenesis of this disease. Interferons (IFNs) are cytokines that play a key role in autoimmune/inflammatory disorders because of their pro- and anti-inflammatory properties as well as their immunoregulatory functions. An increased expression of IFN-regulated genes, widely known as an IFN signature, has been reported in blood and tissue from patients with autoimmune disorders. In this review, we present the function as well as the clinical and therapeutic potential of the IFN signature. Current data demonstrate that the IFN signature can be used as a biomarker that defines disease activity in autoimmune diseases, although this has not been thoroughly studied in IBD. Consequently, further investigation of the IFN signature in IBD would be essential for a better understanding of its actions.

T Cell Subsets' Distribution in Elite Karate Athletes as a Response to Physical Effort

Background

During karate fight muscles work at a very high intensity, and their contractions are extremely strong. The movement pattern contains a great number of feints, dodges, frequent changes in movements’ tempo and direction, hits and kicks, all of which is highly stressful for athlete’s organism, including the immune system.

Methods

T lymphocyte subsets’ distribution and selected cytokines in peripheral blood of three elite karate athletes aged 30 years old (range 21–31 years) with minimum 15 years of training experience were analysed in two experiments: at the beginning of the preparatory phase (a progressive test until exhaustion; an analysis of immune system’s selected parameters and cardiorespiratory fitness measures, including VO₂max, VE, AT, MVV, MET, Rf), and during the start-up period (Karate Championships; an analysis of selected parameters of the immune system).

Results

Maximal effort caused an increase in total lymphocyte percentage (p<0.05). A decrease in Th cells in recovery (p<0.05 compared to post-exercise), and an increase in Th naïve cells in recovery (p<0.05) were observed. A significant increase in CD8⁺ central memory cells (p<0.05) was found only after the progressive test, and no changes in both central and effector memory subsets of CD4⁺ cells during the first experiment. An increase (p<0.05) in Treg and Th1 and a decrease (p<0.05) in Th2 cells’ distribution during recovery time were found. Additionally, changes (p<0.05) in TNF-α, IL-6, IL-8, IL-10 and IL-12p70 were observed.

Conclusion

Post-effort disorder in immune balance activated compensation pathways involving CD4⁺ cells. Treg and Th1 cells seem to be subsets of key importance involved in the anabolic effect of physical effort, at least among karate athletes.

Analysis of selected T cell subsets in peripheral blood after exhaustive effort among elite soccer players

Introduction

Physical exercise induces developing of naïve T lymphocyte subsets into polarised effector ones by immune system. The aim of the study was to examine the influence of exhaustive effort on the selected Th cell subsets and inflammation markers among soccer players.

Materials and methods

Fourteen soccer players aged 18 (16-21) years old performed the progressive efficiency test on mechanical treadmill. Th and Tc memory lymphocytes’ subsets and selected cytokine concentrations pre-exercise, post-exercise and in recovery were analysed by flow cytometry.

Results

Physical effort induced changes in Th cell percentages. Increase in recovery Treg and Th17 cell subsets’ percentages in comparison to pre-exercise values were observed (10.98 (9.83-14.07) vs. 3.95 (3.15-5.53), P < 0.001 in autumn; 10.58 (7.54-12.67) vs. 4.83 (3.73-6.81), P < 0.010 in spring for Treg and 29.21 (26.34-32.16) vs. 21.64 (18.48-25.76) in autumn; 27.15 (24.60-29.16) vs. 17.43 (15.83-19.77) in spring, both P < 0.010; for Th17, respectively). Increases in Th1 cell percentages post-exercise (31.86 (28.72-33.72) in autumn, 25.60 (21.50-29.19) in spring, both P < 0.010) and in recovery (34.64 (31.21-38.20) in autumn; 26.68 (25.17-28.07) in spring, both P < 0.001) compared to pre-exercise (22.70 (21.21-26.74) for autumn and 15.64 (14.38-19.63) for spring, respectively) were found. Interestingly, no changes in Th2 cell subsets were found. Post-exercise and recovery changes in IL-6, IL-8, TNF-α and IL-10 were also observed.

Conclusions

It seems that the given effort in the progressive test induced an anabolic effect being related not only with cytokine profile but also with CD4⁺ T cells’ differentiation and peripheral distribution.

A review of ixekizumab in the treatment of psoriatic arthritis

INTRODUCTION

Psoriatic arthritis (PsA) is a heterogeneous inflammatory disorder with articular, peri-articular, and extra-articular features along with selected co-morbidities as a sequela to chronic inflammation. There is accumulating evidence that the Th-17 signaling pathway is of critical importance in PsA pathogenesis. Areas covered: Ixekizumab (IXE) is a humanized immunoglobulin G subclass 4 (IgG4) monoclonal antibody directed against IL-17A. Two phase III randomized clinical trials, SPIRIT-P1 and SPIRIT-P2, unequivocally demonstrated superiority of IXE (80 mg every two or 4 weeks) dosing over placebo in moderate-to-severe PsA patients that failed either NSAIDs, conventional disease-modifying anti-rheumatic drugs (csDMARDs), or tumor necrosis factor-α inhibitors (TNFi) for numerous articular and cutaneous parameters. IXE also delayed structural progression of PsA. No new safety signals were identified as compared with chronic plaque psoriasis studies which included many more patients. Expert opinion: IXE is a highly effective treatment for moderate to severe PsA patients, including those that have been previously exposed to csDMARD and TNFi. Most domains of PsA significantly improved with IXE treatment and disease modification was achieved.

Characterization of variations in IL23A and IL23R genes: possible roles in multiple sclerosis and other neuroinflammatory demyelinating diseases

Multiple sclerosis is among the most serious inflammatory demyelinating diseases (IDD). Interleukin-23A (IL23A) regulates and coordinates the activities of immune cells by interacting with its receptor IL23R and plays key roles in the pathogenesis of immune inflammatory diseases. IDD, deemed to be a kind of autoimmune diseases, may involve IL23A in the pathogenesis. The aim of this work was to validate the hypothesized involvement of IL-23A and its receptor in IDD. We sequenced the IL-23A and IL-23R genes for 206 Chinese Han IDD patients and evaluated SNPs within or near those genes. The serum levels of IL23A in IDD participants were analyzed using ELISA. The statistical analyses were conducted using Chi-Square Tests as implemented in SPSS (version 19.0). The Hardy-Weinberg equilibrium test of the population was carried out using online software OEGE. Three variants rs2066808, rs2371494, rs11575248 in IL-23A gene and one variant rs1884444 in IL-23R gene were demonstrated to be associated with the risk of MS or other IDD diseases, and the expression level of serum IL-23A in the MS patients was also altered. We conclude that variants in IL-23A and IL-23R genes were associated with the risk of MS or other IDD diseases.

Exercise Inhibits the Effects of Smoke-Induced COPD Involving Modulation of STAT3

PURPOSE

Evaluate the participation of STAT3 in the effects of aerobic exercise (AE) in a model of smoke-induced COPD.

METHODS

C57Bl/6 male mice were divided into control, Exe, COPD, and COPD+Exe groups. Smoke were administered during 90 days. Treadmill aerobic training begun on day 61 until day 90. Pulmonary inflammation, systemic inflammation, the level of lung emphysema, and the airway remodeling were evaluated. Analysis of integral and phosphorylated expression of STAT3 by airway epithelial cells, peribronchial leukocytes, and parenchymal leukocytes was performed.

RESULTS

AE inhibited smoke-induced accumulation of total cells (p < 0.001), lymphocytes (p < 0.001), and neutrophils (p < 0.001) in BAL, as well as BAL levels of IL-1β (p < 0.001), CXCL1 (p < 0.001), IL-17 (p < 0.001), and TNF-α (p < 0.05), while increased the levels of IL-10 (p < 0.001). AE also inhibited smoke-induced increases in total leukocytes (p < 0.001), neutrophils (p < 0.05), lymphocytes (p < 0.001), and monocytes (p < 0.01) in blood, as well as serum levels of IL-1β (p < 0.01), CXCL1 (p < 0.01), IL-17 (p < 0.05), and TNF-α (p < 0.01), while increased the levels of IL-10 (p < 0.001). AE reduced smoke-induced emphysema (p < 0.001) and collagen fiber accumulation in the airways (p < 0.001). AE reduced smoke-induced STAT3 and phospho-STAT3 expression in airway epithelial cells (p < 0.001), peribronchial leukocytes (p < 0.001), and parenchymal leukocytes (p < 0.001).

CONCLUSIONS

AE reduces smoke-induced COPD phenotype involving STAT3.

New treatment targets for axial spondyloarthritis

Axial spondyloarthritis (axSpA) patients can be divided into those with structural damage in the SI joint visible on X-rays, termed radiographic axSpA or AS, and those in an earlier phase of the disease, without structural damage in the SI joint, termed non-radiographic axSpA. TNF-blockers have been shown to be highly effective in the treatment of active axSpA. Interestingly, conventional DMARDs and also non-TNF-blocker biologics targeting IL-1, IL-6 and T cells (abatacept) are not effective. Recent interest has focused on the cytokines IL-23 and IL-17 as potential treatment targets in axSpA. An open-label trial with ustekinumab showed a good efficacy in AS patients. Two placebo-controlled phase 3 trials with a mAb blocking IL-17, secukinumab, showed a good reduction in disease activity, similar to that shown for TNF blockers. Probably triggered by inflammation, new bone formation is another hallmark in AS and a potentially important treatment target. However, a previously reported inhibitory effect of NSAID treatment could not be confirmed in a recent NSAID trial.

Mapping the Energetic Epitope of an Antibody/Interleukin-23 Interaction with Hydrogen/Deuterium Exchange, Fast Photochemical Oxidation of Proteins Mass Spectrometry, and Alanine Shave Mutagenesis

Epitope mapping the specific residues of an antibody/antigen interaction can be used to support mechanistic interpretation, antibody optimization, and epitope novelty assessment. Thus, there is a strong need for mapping methods, particularly integrative ones. Here, we report the identification of an energetic epitope by determining the interfacial hot-spot that dominates the binding affinity for an anti-interleukin-23 (anti-IL-23) antibody by using the complementary approaches of hydrogen/deuterium exchange mass spectrometry (HDX-MS), fast photochemical oxidation of proteins (FPOP), alanine shave mutagenesis, and binding analytics. Five peptide regions on IL-23 with reduced backbone amide solvent accessibility upon antibody binding were identified by HDX-MS, and five different peptides over the same three regions were identified by FPOP. In addition, FPOP analysis at the residue level reveals potentially key interacting residues. Mutants with 3-5 residues changed to alanine have no measurable differences from wild-type IL-23 except for binding of and signaling blockade by the 7B7 anti-IL-23 antibody. The M5 IL-23 mutant differs from wild-type by five alanine substitutions and represents the dominant energetic epitope of 7B7. M5 shows a dramatic decrease in binding to BMS-986010 (which contains the 7B7 Fab, where Fab is fragment antigen-binding region of an antibody), yet it maintains functional activity, binding to p40 and p19 specific reagents, and maintains biophysical properties similar to wild-type IL-23 (monomeric state, thermal stability, and secondary structural features).

Analysis of the association of chronic spontaneous urticaria with interlekin-4, -10, transforming growth factor-β1, interferon-γ, interleukin-17A and -23 by autologous serum skin test

Aim

To contribute to the understanding of the pathogenesis of chronic spontaneous urticaria (CSU) by identifying its relationship with autoimmunity and cytokines using the autologous serum skin test (ASST) and peripheral blood mononuclear cell culture (PBMC) method.

Material and methods

Interleukins (IL)-4, IL-10, transforming growth factor (TGF-β1), interferon (IFN)-γ, IL-17A, and IL-23 levels in cell supernatants obtained by the PBMC method were measured using ELISA. Disease activity was assessed by determining the urticaria activity score (UAS).

Results

A total of 40 patients diagnosed with CSU participated in this study. Twenty patients had positive ASST results, and 20 had negative results. The control group included 20 healthy volunteers. We found that the IL-23 (p = 0.01), IL-10 (p = 0.04) and IL-4 (p = 0.04) levels of the patient groups were significantly lower compared with those of the control group. The IL-23 (p = 0.009), IL-10 (p = 0.009), IL-4 (p = 0.001), and IL-17 (p = 0.05) levels of the ASST(–) patient group were significantly lower compared with those of the control group. In addition, the IL-4 (p = 0.03) and IFN-γ (p = 0.05) levels of the ASST(+) patient group were significantly lower compared with those of the control group, and the ASST(+) patients had a significantly higher UAS than the ASST(–) patients (p = 0.021).

Conclusions

These results, when considered together with current reports in the literature, indicate that immune dysregulation occurs in the pathogenesis of CSU, causing cytokine imbalance.

CCAAT/Enhancer-binding protein β promotes pathogenesis of EAE

The CCAAT/Enhancer Binding Protein β (C/EBPβ) transcription factor is activated by multiple inflammatory stimuli, including IL-17 and LPS, and C/EBPβ itself regulates numerous genes involved in inflammation. However, the role of C/EBPβ in driving autoimmunity is not well understood. Here, we demonstrate that Cebpb^-/- mice are resistant to EAE. Cebpb^-/- mice exhibited reduced lymphocyte and APC infiltration into CNS following EAE induction. Furthermore, MOG-induced Th17 cytokine production was impaired in draining LN, indicating defects in Th17 cell priming. In vitro Th17 polarization studies indicated that T cell responses are not inherently defective, instead supporting the known roles for C/EBPβ in myeloid lineage cell activation as the likely mechanism for defective Th17 priming in vivo. However, we did uncover an unexpected role for C/EBPβ in regulating ll23r expression in APCs. ChIP assays confirmed that C/EBPβ binds directly to the Il23r gene promoter in dendritic cells and Th17 cells. These data establish C/EBPβ as a key driver of autoimmune inflammation in EAE, and propose a novel role for C/EBPβ in regulation of IL-23R expression.

Plasma levels of Th17-related cytokines and complement C3 correlated with aggressive behavior in patients with schizophrenia

Increasing evidence indicates that immune inflammatory processes, especially autoimmune reaction, should be considered in the pathophysiology of schizophrenia and aggressive behavior. The present study aimed to explore the correlation between immune factors (C3 and Th17-related cytokines) and aggressive behavior in schizophrenia patients. Forty schizophrenia patients and forty age- and gender-matched healthy controls participated in the study. Blood samples were assessed by ELISA upon enrollment. Positive and negative syndrome scale (PANSS) and modified overt aggression scale (MOAS) were used to estimate the severity and aggressive symptoms of schizophrenia patients. Plasma levels of IL-17, IL-23, and TGF-β1 in schizophrenia patients were significantly higher than those in healthy controls [(37.63±17.82) vs. (29.34±10.38)pg/ml, p=0.02; (101.40±135.26) vs. (13.09±5.94) pg/ml, p=0.01; (2864.57±2163.61) vs. (1839.69±1797.73)pg/ml, p=0.04], whereas C3 levels were significantly lower in schizophrenia patients [( 120,479.67± 65,612.50) vs. ( 208,060.21± 217,008.21)ng/ml, p=0.02]. IL-17, IL-23, and TGF-β1 levels were positively related to total scores of MOAS (p=0.02, p=0.02 and p=0.03, respectively) and PANSS (p=0.04, p=0.04 and p=0.02, respectively), whereas C3 levels were negatively related to total PANSS scores (p=0.03). IL-17 and IL-23 levels were positively correlated with PANSS excited component scores (p=0.04 and p=0.01, respectively). Our findings suggested that the Th17-related cytokine levels were positively related to the severity of schizophrenia and aggressive behavior, whereas C3 levels were negatively related to the severity of schizophrenia. This study demonstrated that elevated levels of Th17-related cytokines and decreased levels of C3 could be potential biomarkers for schizophrenia and aggressive behavior.

Smad-dependent mechanisms of inflammatory bone destruction

Homeostatic bone remodelling becomes disturbed in a variety of pathologic conditions that affect the skeleton, including inflammatory diseases. Rheumatoid arthritis is the prototype of an inflammatory arthritis characterised by chronic inflammation, progressive cartilage destruction and focal bone erosions and is a prime example for a disease with disturbed bone homeostasis. The inflammatory milieu favours the recruitment and activation of osteoclasts, which have been found to be the cells that are primarily responsible for bone erosions in many animal models of inflammatory arthritis. Among the inflammatory modulators, members of the transforming growth factor (TGF)-β super family are shown to be important regulators in osteoclastogenesis with Smad-mediated signalling being crucial for inducing osteoclast differentiation. These findings have opened a new field for exploring mechanisms of osteoclast differentiation under inflammatory conditions. Recent studies have shown that the TGF-β superfamily members TGF-β1, myostatin and activin A directly regulate osteoclast differentiation through mechanisms that depend on the RANKL–RANK interplay. These growth factors transduce their signals through type I and II receptor serine/threonine kinases, thereby activating the Smad pathway. In this review, we describe the impact of inflammation-induced Smad signalling in osteoclast development and subsequently bone erosion in rheumatoid arthritis.

Tiam1/Rac1 complex controls Il17a transcription and autoimmunity

RORγt is a master transcription factor of Th17 cells and considered as a promising drug target for the treatment of autoimmune diseases. Here, we show the guanine nucleotide exchange factor, Tiam1, and its cognate Rho-family G protein, Rac1, regulate interleukin (IL)17A transcription and autoimmunity. Whereas Tiam1 genetic deficiency weakens IL-17A expression partially and inhibits the development of experimental autoimmune encephalomyelitis (EAE), deletion of Rac1 in T cells exhibits more robust effects on Th17 cells and EAE. We demonstrate Tiam1 and Rac1 form a complex with RORγt in the nuclear compartment of Th17 cells, and together bind and activate the Il17 promoter. The clinical relevance of these findings is emphasized by pharmacological targeting of Rac1 that suppresses both murine and human Th17 cells as well as EAE. Thus, our findings highlight a regulatory pathway of Tiam1/Rac1 in Th17 cells and suggest that it may be a therapeutic target in multiple sclerosis.

Tiam1 is a guanine nucleotide exchange factor for the Rho-family GTPase Rac1. Here, the authors show that nuclear Tiam1 and Rac1 bind to RORγt on the IL-17 promoter, activating its transcription, and that inhibiting Tiam1/Rac1 is beneficial in a mouse model of autoimmunity.

Suppression of TH17-mediated pathology through BET bromodomain inhibition

Epigenetic control of gene expression is enforced in part through histone modifications. Bromodomain and extra terminal domain (BET) proteins function as crucial chromatin readers, responsible for interpretation of the chromatin code in diverse cellular contexts, ultimately impacting gene transcription. BET proteins can play a major role in inflammation by profoundly affecting the biology of the T_helper 17 (T_H17) lineage. We summarize recent studies focusing on BET inhibition as a viable therapeutic alternative for the control of autoimmune diseases driven by aberrant activation of T_H17 cells.

Biotin deficiency enhances the inflammatory response of human dendritic cells

The water-soluble biotin (vitamin B7) is indispensable for normal human health. The vitamin acts as a cofactor for five carboxylases that are critical for fatty acid, glucose, and amino acid metabolism. Biotin deficiency is associated with various diseases, and mice deficient in this vitamin display enhanced inflammation. Previous studies have shown that biotin affects the functions of adaptive immune T and NK cells, but its effect(s) on innate immune cells is not known. Because of that and because vitamins such as vitamins A and D have a profound effect on dendritic cell (DC) function, we investigated the effect of biotin levels on the functions of human monocyte-derived DCs. Culture of DCs in a biotin-deficient medium (BDM) and subsequent activation with LPS resulted in enhanced secretion of the proinflammatory cytokines TNF-α, IL-12p40, IL-23, and IL-1β compared with LPS-activated DCs cultured in biotin-sufficient (control) and biotin-oversupplemented media. Furthermore, LPS-activated DCs cultured in BDM displayed a significantly higher induction of IFN-γ and IL-17 indicating Th1/Th17 bias in T cells compared with cells maintained in biotin control or biotin-oversupplemented media. Investigations into the mechanisms suggested that impaired activation of AMP kinase in DCs cultured in BDM may be responsible for the observed increase in inflammatory responses. In summary, these results demonstrate for the first time that biotin deficiency enhances the inflammatory responses of DCs. This may therefore be one of the mechanism(s) that mediates the observed inflammation that occurs in biotin deficiency.

Antibodies from donor B cells perpetuate cutaneous chronic graft-versus-host disease in mice

Cutaneous sclerosis is one of the most common clinical manifestations of chronic graft-versus-host disease (cGVHD). Donor CD4(+) T and B cells play important roles in cGVHD pathogenesis, but the role of antibodies from donor B cells remains unclear. In the current studies, we generated immunoglobulin (Ig)H(µγ1) DBA/2 mice whose B cells have normal antigen-presentation and regulatory functions but cannot secrete antibodies. With a murine cGVHD model using DBA/2 donors and BALB/c recipients, we have shown that wild-type (WT) grafts induce persistent cGVHD with damage in the thymus, peripheral lymphoid organs, and skin, as well as cutaneous T helper 17 cell (Th17) infiltration. In contrast, IgH(µγ1) grafts induced only transient cGVHD with little damage in the thymus or peripheral lymph organs or with little cutaneous Th17 infiltration. Injections of IgG-containing sera from cGVHD recipients given WT grafts but not IgG-deficient sera from recipients given IgH(µγ1) grafts led to deposition of IgG in the thymus and skin, with resulting damage in the thymus and peripheral lymph organs, cutaneous Th17 infiltration, and perpetuation of cGVHD in recipients given IgH(µγ1) grafts. These results indicate that donor B-cell antibodies augment cutaneous cGVHD in part by damaging the thymus and increasing tissue infiltration of pathogenic Th17 cells.

Th17 and regulatory T cells contribute to the in situ immune response in skin lesions of Jorge Lobo's disease

Jorge Lobo's disease (JLD) is a chronic granulomatous mycosis described in various Latin American countries. The main objective of the present study was to investigate the possible role of Th17 and Foxp3+ Treg cells in the pathogenesis of Jorge Lobo's disease. Human skin biopsies were submitted to an immunohistochemistry protocol to detect Foxp3, interleukin (IL)-1beta, CD25, IL-6, IL-17, and IL-23. The epidermis presented acanthosis, hyperkeratosis, and frequent presence of fungi. The dermis presented inflammatory infiltrate comprising macrophages, lymphocytes, epithelioid and multinucleated cells, and an intense number of fungi. Foxp3+ Treg cells and IL-17+ cells were visualized in lymphocytes in the inflammatory infiltrate. IL-1, IL-2R (CD25), IL-6, and IL-23 were visualized in the dermis, intermingled with fungal cells, permeating or participating of the granuloma. Following IL-17, the most prominent cytokine was IL-6. IL-23 and cells expressing CD25 were present in fewer number. The comparative analysis between IL-17 and Foxp3 demonstrated a statistically significant increased number of IL-17+ cells. Th17 cells play a role in the immune response of JLD. IL-1beta and IL-6 added to the previously described increased number of TGF-beta would stimulate such pattern of response. Th17 cells could be present as an effort to modulate the local immune response; however, high levels of a Th17 profile could overcome the role of Treg cells. The unbalance between Treg/Th17 cells seems to corroborate with the less effective immune response against the fungus.

NFATc1 deficiency in T cells protects mice from experimental autoimmune encephalomyelitis

NFATc1 is a member of the nuclear factor of activated T cells (NFAT) family of transcription factors. NFAT is activated upon T-cell receptor activation followed by intracytoplasmatic calcium influx where calmodulin, a calcium sensor protein, activates the phosphatase calcineurin that dephosphorylates NFAT proteins and results in NFAT nuclear import. Here, we show the analysis of conditional NFATc1-deficient mice bearing a deletion of NFATc1 in CD4(+) and CD8(+) T cells. NFATc1-deficient CD4(+) T cells polarized under Th17 conditions express reduced levels of the Th17-associated transcription factor RORγT (where ROR is RAR-related orphan receptor) as well as the Th17-associated cytokines IL-17A, IL-17F, IL-21, and IL-10. In the murine model of experimental EAE, we found a strong reduction of the disease outcome in conditional NFATc1-deficient mice, as compared with control littermates. This was accompanied by a diminished inflammation in the brain and spinal cord and reduced IL-17A and IFN-γ expression by antigen-specific spleen, spinal cord, and brain cells. Altogether, these results reveal an important role of NFATc1 in inducing Th17-cell responses and IFN-γ, both being relevant for the EAE development.

Selective targeting of the IL23 pathway: Generation and characterization of a novel high-affinity humanized anti-IL23A antibody

Herein, we describe the generation and characterization of BI 655066, a novel, highly potent neutralizing anti-interleukin-23 (IL23) monoclonal antibody in clinical development for autoimmune conditions, including psoriasis and Crohn's disease. IL23 is a key driver of the differentiation, maintenance, and activity of a number of immune cell subsets, including T helper 17 (Th17) cells, which are believed to mediate the pathogenesis of several immune-mediated disorders. Thus, IL23 neutralization is an attractive therapeutic approach. Designing an antibody for clinical activity and convenience for the patient requires certain properties, such as high affinity, specificity, and solubility. These properties were achieved by directed design of the immunization, lead identification, and humanization procedures. Favorable substance and pharmacokinetic properties were established by biophysical assessments and studies in cynomolgus monkeys.

IL-23 and TGF-β1 levels as potential predictive biomarkers in treatment of bipolar I disorder with acute manic episode

BACKGROUND

Growing evidence suggests that immune dysfunction may be involved in the physiopathology of bipolar disorders, with typical first-line treatment using lithium and quetiapine serving to restore pro-inflammation status. This study aimed to explore the relationship between inflammatory cytokines-especially regulatory factors and the effect of combination treatment-with quetiapine and lithium in manic patients.

METHODS

41 patients of bipolar I disorder with manic episode were enrolled and received combination treatment with quetiapine and lithium. Blood sampling and assessments were performed at baseline and after 8-week treatment. YMRS was used to evaluate the severity of manic symptoms at the same time of detecting plasma levels. A control group comprised of 36 age and gender matched healthy volunteers were enrolled, and their blood samples were assessed at the time of enrollment.

RESULTS

TGF-β1 and IL-23 plasma levels in patients were significantly higher than healthy controls at baseline (P<0.05). When comparing remitted patients with non-remitted patients, initial plasma level TGF-β1 was higher (P=0.029) while IL-23 was lower (P=0.035). The plasma levels of TNF-α, TGF-β1, IL-23 and IL-17 significantly decreased after treatment among the patients who achieved response (P<0.05).

LIMITATIONS

The relatively small sample size in patients and control groups should be considered as a limitation of the study.

CONCLUSIONS

The high initial plasma level of TGF-β1 and low initial plasma level of IL-23 indicated better prognosis during combination treatment with quetiapine and lithium in manic patients. The trend of decreasing plasma levels of TNF-α, TGF-β1, IL-23 and IL-17 indicated therapeutic effect.

Increased interleukin-23/17 axis and C-reactive protein are associated with severity of acute pancreatitis in patients

OBJECTIVE

The interleukin (IL)-23/IL-17 axis plays an important role in various inflammatory conditions but its function in acute pancreatitis (AP) is not well understood. The present study investigated the relationship between serum levels of IL-23, IL-17, and C-reactive protein (CRP) in patients and the severity of AP.

METHODS

Eighty-five patients with AP were categorized into mild group, moderately severe group, and severe group according to the revised Atlanta classification, 2012. Serum levels of IL-23 and IL-17 were measured by enzyme-linked immunosorbent assay in patients 48 hours after admission. The CRP levels of patients were also measured on admission and 48 hours after admission.

RESULTS

The serum levels of CRP of patients on admission and 48 hours after admission and levels of IL-23 and IL-17 of patients 48 hours after admission increased alone with the severity of AP, respectively (P < 0.01). The serum levels of IL-23 and IL-17 in the patients were correlated with CRP levels (r = 0.234, r = 0.552, P < 0.001, respectively).

CONCLUSIONS

The serum levels of IL-17, IL-23, and CRP are correlated with the severity of AP and represent valuable prognostic factors in the assessment of disease severity of patients with AP.

The involvement of TLR2 and TLR4 in cytokine and nitric oxide production in visceral leishmaniasis patients before and after treatment with anti-leishmanial drugs

Toll-like receptors (TLRs) have significant involvement in Leishmania infection, although little is known about the relationship between these receptors, cytokines and nitric oxide (NO) in patients with visceral leishmaniasis (VL) before or after treatment with anti-leishmanial drugs. The goal of this study was to evaluate the expression of TLR2 and TLR4 in CD3+ and CD14+ cells and the production of TNF-α, IFN-γ, IL-17, IL-10, TGF-β and NO in peripheral blood mononuclear cells (PBMCs) from VL patients pre- and post-treatment with anti-leishmanial drugs. In addition, we investigated whether these receptors were involved in the production of these cytokines and NO. In the active VL patients, increased TLR2 and TLR4 expression in lymphocytes and monocytes, increased production of TNF-α, IL-10 and TGF-β and decreased production of IFN-γ, IL-17 and NO were observed. After treatment, TLR2 and TLR4 were still expressed in lymphocytes and monocytes, the TNF-α and IL-10 levels were lower, the production of IFN-γ, IL-17 and NO was higher, and the TGF-β level remained high. Before treatment, the production of TNF-α and NO was associated with TLR2 and TLR4 expression, while IL-10 production was only associated with TLR2 expression. After treatment, both receptors were associated with the production of TNF-α, IFN-γ, IL-10 and NO, while the production of IL-17 was associated only with TLR4 expression. The results presented in this study suggest that both TLR2 and TLR4 participate in the modulation of cytokine and NO production in VL patients, contributing to the pathogenesis of VL prior to treatment and the protective immune response after treatment.

Effects of isoxazolo-pyridinone 7e, a potent activator of the Nurr1 signaling pathway, on experimental autoimmune encephalomyelitis in mice

Multiple sclerosis (MS) is an autoimmune chronic disease of the central nervous system (CNS) characterized by immune-mediated inflammation, demyelination and subsequent axonal damage. Gene expression profiling showed that Nurr1, an orphan nuclear receptor, is down-regulated in peripheral blood mononuclear cells of MS patients. Nurr1 exerts an anti-inflammatory role repressing the activity of the pro-inflammatory transcription factor NF-kB. Here, we report that the preventive treatment with isoxazolo-pyridinone 7e, an activator of Nurr1 signaling pathway, reduces the incidence and the severity of a MS murine model, i.e. experimental autoimmune encephalomyelitis (EAE). The compound is able to attenuate inflammation and neurodegeneration in spinal cords of EAE mice by an NF-kB pathway-dependent process.

IL-23 promotes TCR-mediated negative selection of thymocytes through the upregulation of IL-23 receptor and RORγt

Transient thymic involution is frequently found during inflammation, yet the mode of action of inflammatory cytokines is not well defined. Here we report that interleukin-23 (IL-23) production by the thymic dendritic cells (DCs) promotes apoptosis of the CD4^hiCD8^hi double positive (DP) thymocytes. A deficiency in IL-23 signaling interferes with negative selection in the male D^b/H-Y T-cell receptor (TCR) transgenic mice. IL-23 plus TCR signaling results in significant up-regulation of IL-23 receptor (IL-23R) expressed predominantly on CD4^hiCD8^hiCD3⁺αβTCR⁺ DP thymocytes, and leads to RORγt dependent apoptosis. These results extend the action of IL-23 beyond its peripheral effects to a unique role in TCR mediated negative selection including elimination of natural T regulatory cells in the thymus.

Autoimmune pancreatitis: pathogenesis, latest developments and clinical guidance

Recently, autoimmune pancreatitis has been classified into two subtypes. Type 1 is related to immunoglobulin G4 and type 2 is related to granulocytic epithelial lesions, but pathogenetic mechanisms in both still remain unclear. Apart from type 2 autoimmune pancreatitis, the pathological features of type 1 autoimmune pancreatitis with increased serum immunoglobulin G4/immunoglobulin E levels, abundant infiltration of immunoglobulin G4+plasmacytes and lymphocytes, fibrosis, and steroid responsiveness are suggestive of abnormal immunity such as allergy or autoimmunity. Although pathophysiological conditions seem to be different in each, both respond well to steroid drugs. After remission, the patients with type 1 autoimmune pancreatitis show high relapse rates (30-50% within 6-12 months), whereas those with type 2 autoimmune pancreatitis seldom relapse. After remission, the steroid maintenance therapy and therapeutic strategy for relapsing patients with type 1 is different among local expertise. In this paper, recent advances in pathogenesis and clinical guidance for therapy are discussed.

Focused specificity of intestinal TH17 cells towards commensal bacterial antigens

T-helper-17 (TH17) cells have critical roles in mucosal defence and in autoimmune disease pathogenesis. They are most abundant in the small intestine lamina propria, where their presence requires colonization of mice with microbiota. Segmented filamentous bacteria (SFB) are sufficient to induce TH17 cells and to promote TH17-dependent autoimmune disease in animal models. However, the specificity of TH17 cells, the mechanism of their induction by distinct bacteria, and the means by which they foster tissue-specific inflammation remain unknown. Here we show that the T-cell antigen receptor (TCR) repertoire of intestinal TH17 cells in SFB-colonized mice has minimal overlap with that of other intestinal CD4(+) T cells and that most TH17 cells, but not other T cells, recognize antigens encoded by SFB. T cells with antigen receptors specific for SFB-encoded peptides differentiated into RORγt-expressing TH17 cells, even if SFB-colonized mice also harboured a strong TH1 cell inducer, Listeria monocytogenes, in their intestine. The match of T-cell effector function with antigen specificity is thus determined by the type of bacteria that produce the antigen. These findings have significant implications for understanding how commensal microbiota contribute to organ-specific autoimmunity and for developing novel mucosal vaccines.

Specific microbiota-induced intestinal Th17 differentiation requires MHC class II but not GALT and mesenteric lymph nodes

IL-17-expressing CD4+ T lymphocytes (Th17 cells) naturally reside in the intestine where specific cytokines and microbiota, such as segmented filamentous bacteria (SFB), promote their differentiation. Intestinal Th17 cells are thought to initially differentiate in the GALT and/or mesenteric lymph nodes upon Ag encounter and subsequently home to the lamina propria (LP) where they mediate effector functions. However, whether GALT and/or mesenteric lymph nodes are required for intestinal Th17 differentiation as well as how microbiota containing SFB regulate Ag-specific intestinal Th17 cells remain poorly defined. In this study, we observed that naive CD4+ T cells were abundant in the intestinal LP prior to weaning and that the accumulation of Th17 cells in response to microbiota containing SFB occurred in the absence of lymphotoxin-dependent lymphoid structures and the spleen. Furthermore, the differentiation of intestinal Th17 cells in the presence of microbiota containing SFB was dependent on MHC class II expression by CD11c+ cells. Lastly, the differentiation of Ag-specific Th17 cells required both the presence of cognate Ag and microbiota containing SFB. These findings suggest that microbiota containing SFB create an intestinal milieu that may induce Ag-specific Th17 differentiation against food and/or bacterial Ags directly in the intestinal LP.

Inflammatory bowel disease

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic, relapsing inflammatory condition of the gastrointestinal tract. CD and UC have distinct pathologic and clinical characteristics and despite the extensive amount of research conducted over the past decades, their pathogenesis remains still poorly understood. So far, the accepted dogma is that IBD results from dysregulated mucosal immune response to environmental factors in genetical susceptible hosts. Various components are implicated in the pathogenesis of IBD, including genetic susceptibility, environmental and microbial factors, intestinal epithelial cells and components of innate and adaptive immune system. Given the complexity of IBD, several different animal models of IBD have been developed during the last years. Animal models are very important tools to study the involvement of various factors in the pathogenesis of IBD and, importantly, to test new therapeutic options. This review examines some of the key components that have been found to be closely associated to IBD and describe the distinct features of some of the most important IBD models.

Unexpected targets and triggers of autoimmunity

Recent findings indicate that the role of Th17 cells in the pathogenesis of tissue inflammation and autoimmunity has become rather complicated. While interleukin-17 (IL-17) producing CD4+ T cells are found frequently within the peripheral target tissue during the course of autoimmune disease, these cells may contribute to or protect from inflammation. Accumulating reports have revealed the existence of both pathogenic and non-pathogenic Th17 cells. These Th17 subsets produce the signature cytokines IL-17A and IL-17F yet have distinct and divergent roles in inducing autoimmune tissue inflammation. Comparative genomic sequence analyses between the pathogenic and non-pathogenic Th17 cells have exposed unexpected and extensive population heterogeneity within the Th17 subset. Here we review some of the unexpected factors that may drive pathogenic divergence. Understanding the functional consequences of Th17 cell diversity may allow for the selection of more precise targets for intervention in autoimmune and inflammatory diseases.

Role of Th17 Cells in the Pathogenesis of Human IBD

The gastrointestinal tract plays a central role in immune system, being able to mount efficient immune responses against pathogens, keeping the homeostasis of the human gut. However, conditions like Crohn's disease (CD) or ulcerative colitis (UC), the main forms of inflammatory bowel diseases (IBD), are related to an excessive and uncontrolled immune response against normal microbiota, through the activation of CD4(+) T helper (Th) cells. Classically, IBD was thought to be primarily mediated by Th1 cells in CD or Th2 cells in UC, but it is now known that Th17 cells and their related cytokines are crucial mediators in both conditions. Th17 cells massively infiltrate the inflamed intestine of IBD patients, where they produce interleukin- (IL-) 17A and other cytokines, triggering and amplifying the inflammatory process. However, these cells show functional plasticity, and they can be converted into either IFN- γ producing Th1 cells or regulatory T cells. This review will summarize the current knowledge regarding the regulation and functional role of Th17 cells in the gut. Deeper insights into their plasticity in inflammatory conditions will contribute to advancing our understanding of the mechanisms that regulate mucosal homeostasis and inflammation in the gut, promoting the design of novel therapeutic approaches for IBD.

Parasites: what are they good for?

Parasitic diseases caused by helminth and protozoan infections remain one of the largest global public health problems for mankind. While natural immunity in man is rare or slow to develop for many parasites, the immune response is capable of recognizing and responding to infection by utilizing a number of different immunological mechanisms. This special topics journal issue examines many of the key findings in the recent literature regarding the immune response against helminth and protozoan infections, as well as highlighting areas in which our current knowledge falls short. The question of how we can tailor immune responses to prevent or reduce disease burden is a burning question within the field of immunoparasitology.

Interleukin-22: A Bridge Between Epithelial Innate Host Defense and Immune Cells

Interleukin-22 (IL-22), an IL-10 family cytokine, is produced by various leukocytes. The receptor of IL-22, however, is preferentially detected on peripheral tissue epithelial cells. IL-22 functions as a unique messenger from immune system to tissue epithelial cells and to regulate homeostasis of epithelia. IL-22 is able to directly enhance antimicrobial defense mechanisms in epithelial cells and to facilitate epithelial barrier repair and wound healing process. It, therefore, possesses an irreplaceable role in host defense against certain pathogens that specifically invade epithelial cells. In addition, IL-22 can help to preserve the integrity and homeostasis of various epithelial organs during infection or inflammation. The importance of its tissue-protective function is manifested in many inflammatory situations such as inflammatory bowel diseases (IBD) and hepatitis. On the other hand, as a cytokine, IL-22 is capable of induction of proinflammatory responses, especially in synergy with other cytokines. Consequently, IL-22 contributes to pathogenesis of certain inflammatory diseases for example psoriasis.