Development and function of TH17 cells in health and disease

COX/PGE(2) axis critically regulates effects of LPS on eosinophilia-associated cytokine production in nasal polyps

BACKGROUND

Lipopolysaccharide (LPS) has shown heterogeneous effects on eosinophilic inflammation in airways. However, little is known about how LPS regulates pathogenesis of chronic rhinosinusitis with nasal polyps, a major form of eosinophilic inflammation in the upper airway.

OBJECTIVE

We sought to investigate the effect of LPS on cytokine production by dispersed nasal polyp cells (DNPCs).

METHODS

Either diclofenac-treated or untreated DNPCs were cultured with or without staphylococcal enterotoxin B (SEB) in the presence or absence of LPS, after which the levels of IL-5, IL-13, IL-17A and IFN-γ within the supernatant were measured. The effects of PGE(2) on LPS-induced responses by diclofenac-treated DNPCs were also examined. LPS-induced PGE(2) production and mRNA expression of COX-1, COX-2 and microsomal PGE(2) synthase-1 (m-PGES-1) were measured.

RESULTS

Staphylococcal enterotoxin B induced IL-5, IL-13, IL-17A and IFN-γ production by DNPCs. Pre-treatment with LPS prior to SEB stimulation inhibited production of these cytokines. After stimulation with LPS, PGE(2) production and expression of COX-2 and m-PGES-1 mRNA by DNPCs increased significantly. In the presence of diclofenac, the suppressive effects of LPS were eliminated. LPS pre-treatment enhanced SEB-induced IL-5, IL-13 and IL-17A production in diclofenac-treated DNPCs, while addition of PGE(2) inhibited IL-5, IL-13 and IFN-γ production. LPS alone induced IL-5, IL-13 and IFN- γ production by diclofenac-treated DNPCs, while the addition of EP2 and EP4 receptor-selective agonists, as well as PGE(2) itself, inhibited IL-5 and IL-13 production.

CONCLUSIONS AND CLINICAL RELEVANCE

These results suggest that the regulatory effects of LPS on eosinophilic airway inflammation are controlled via the COX-2/PGE(2) axis. For clinical implications, indiscreet use of non-steroidal anti-inflammatory drugs should be avoided in patients with chronic rhinosinusitis with nasal polyps.

Association of single nucleotide polymorphisms on Interleukin 17 receptor A (IL17RA) gene with aspirin hypersensitivity in asthmatics

AIM

To investigate the association of single nucleotide polymorphisms (SNP) on IL17RA gene with Aspirin Exacerbated Respiratory Disease (AERD) and the functional effect of these variants on expression of IL17RA gene products.

MATERIAL & METHODS

15 SNPs of IL17RA gene were analyzed in 825 normal controls and 143 subjects with AERD and 411 with aspirin-tolerant asthma (ATA) and functionally characterized using measurement of protein and m-RNA expression.

RESULT

Minor alleles frequencies of the three SNPs (-1075 A>G, -947 A>G, -50 C>T) and one haplotype (BL1_ht1) were significantly lower in AERD compared to those in ATA (p(corr)=0.002-0.03). IL17RA protein expression and mRNA amount in CD14(+) peripheral blood monocytes and mononuclear cells were significantly increased in subjects carrying the common alleles homozygote compared with those carrying the minor alleles.

CONCLUSIONS

The minor alleles of the three SNPs may decrease the risk of AERD via attenuation of IL17RA gene expression.

Differences in airway inflammation according to atopic status in patients with chronic rhinitis

Background

Chronic rhinitis is a heterogeneous group of diseases that cause nasal inflammation. And the nose may be a window into the lung in the concept of "one airway one disease."

Objective

This study was conducted to evaluate differences between the different forms of chronic rhinitis in terms of lower airway inflammation.

Methods

Patients that attended the allergy clinic and presented with moderate/severe persistent rhinitis symptoms for more than 1 year were enrolled. The patients with chronic rhinitis were classified into two groups (house dust mites [HDM]-sensitive allergic rhinitis [AR] or non-allergic rhinitis [NAR]) according to the presence of atopy, and additionally according to nasal polyposis and airway hyperresponsiveness, respectively. Medical records were reviewed and the mRNA expression levels of IL-5, IFN-γ, TGF-β1, IL-17A, and IL-25 were evaluated in induced sputum samples in each group.

Results

Induced sputum samples of 53 patients were evaluated. Patients with NAR were significantly older than patients with HDM-sensitive AR (p < 0.05). Nasal polyposis was more prevalent in NAR patients than in HDM-sensitive AR patients (10.2% vs. 62.5%, p < 0.001). The expression levels of IL-17A mRNA were higher in NAR patients, regardless of the presence of airway hyperresponsiveness (p = 0.005).

Conclusion

These results suggest that patients with different forms of chronic rhinitis could have different inflammatory environments in their lower airway and NAR patients might have bronchial inflammation related to the elevated levels of IL-17A compared to HDM-sensitive AR patients.

Th17 helper cell and T-cell immunoglobulin and mucin domain 3 involvement in Guillain-Barré syndrome

OBJECTIVE AND DESIGN

We investigated the involvement of Th17 cells and T-cell immunoglobulin and mucin domain 3 (TIM-3) in Guillain-Barré syndrome (GBS) in comparison to healthy subjects.

MATERIALS AND SUBJECTS

Peripheral blood samples were obtained from 29 healthy subjects and 29 GBS patients.

TREATMENT

Peripheral blood mononuclear cells (PBMCs) and CD4(+) T cells were stimulated with anti-CD3 and anti-CD28 mAbs, in the absence or presence of anti-TIM-3 mAb.

METHODS

mRNA levels of TIM-3 and the transcription factor retinoic acid-related orphan receptor γt (RORγt) were determined by RT-PCR and were expressed relative to β-actin mRNA (housekeeping gene). Serum IFN-γ and IL-17 levels were determined by ELISA.

RESULTS

Compared to controls, relative TIM-3 mRNA levels were lower in both stimulated and unstimulated PBMCs from GBS patients. Unstimulated GBS CD4(+) T cells and GBS CD4+ T cells stimulated with anti-CD3 and CD28 mAbs had higher relative RORγt mRNA expression compared to controls. GBS CD4(+) T cells secreted significantly more IFN-γ and IL-17 in the presence of anti-TIM-3 mAb. GBS patients had (1) higher numbers of Th17, but not Th1 or Th2 cells in peripheral blood and (2) higher serum concentrations of IFN-γ and IL-17 compared to controls.

CONCLUSION

TIM-3 may inhibit Th17 cell activation, thereby modulating their cytokine secretion patterns. Th17 cell differentiation, IL-17 levels, and TIM-3 regulation may be involved in the pathogenesis of GBS.

Innate and adaptive immune responses in asthma

The recognition that asthma is primarily an inflammatory disorder of the airways associated with T helper type 2 (T(H)2) cell-dependent promotion of IgE production and recruitment of mast cells and eosinophils has provided the rationale for disease control using inhaled corticosteroids and other anti-inflammatory drugs. As more has been discovered about the cytokine, chemokine and inflammatory pathways that are associated with T(H)2-driven adaptive immunity, attempts have been made to selectively inhibit these in the hope of discovering new therapeutics as predicted from animal models of allergic inflammation. The limited success of this approach, together with the recognition that asthma is more than allergic inflammation, has drawn attention to the innate immune response in this disease. Recent advances in our understanding of the sentinel role played by innate immunity provides new targets for disease prevention and treatment. These include pathways of innate stimulation by environmental or endogenous pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) to influence the activation and trafficking of DCs, innate sources of cytokines, and the identification of new T cell subsets and lymphoid cells.

Association between polymorphisms in cytokine genes IL-17A and IL-17F and development of allergic rhinitis and comorbid asthma in Chinese subjects

BACKGROUND

Th17 cell lineage, a distinct pro-inflammatory lineage characterized by preferential synthesis of cytokines IL-17A and IL-17F, is thought to play an important role in the pathogenesis of allergic rhinitis (AR).

OBJECTIVES

Our aim was to investigate whether polymorphisms in and around IL-17A and IL-17F genes are associated with AR and comorbid asthma.

METHODS

A case-control comparison was performed in a cohort of 279 AR patients, 197 allergic rhinitis with asthma (AR-A) patients and 281 control Chinese subjects, to investigate associations between 19 tagging single-nucleotide polymorphisms (SNPs) in IL-17A and IL-17F gene regions and manifestation of AR or AR-A. Genotyping was performed using the Sequenom MassARRAY platform.

RESULTS

SNP rs3819024 in IL-17A gene, intergenic SNPs rs1892280 and rs10807439 were specifically associated with AR protective or risk effects, while rs3819024 in IL-17A gene, intergenic SNP rs13192563 in IL-17F gene were associated with AR-A protective or risk effects. Haplotype analysis showed significant AR risk in haplotype AA (rs1892280G-rs13192563A) and AR protective effect in haplotype GT (rs7758579A-rs11966760T); the haplotype AT(rs7758579-rs11966760) were considered AR-A risk.

CONCLUSIONS

Our findings preliminarily indicate IL17A and IL17F SNPs, and some intergenic variants have the potential association with AR and comorbid asthma in Chinese population.

Contribution of interleukin 17A to the development and regulation of allergic inflammation in a murine allergic rhinitis model

BACKGROUND

Interleukin (IL) 17A, a key cytokine of T(H)17 cells, is a well-known proinflammatory cytokine. Despite the important role of T(H)17 cells in acute airway inflammation, the role of IL-17A in allergic rhinitis (AR) remains unclear.

OBJECTIVE

To investigate the role of IL-17A in the allergic response in AR.

METHODS

Wild-type BALB/c and IL-17A-deficient mice were immunized intraperitoneally and were challenged intranasally with ovalbumin. Allergic symptom scores, eosinophil infiltration, serum IgE level, and the levels of several cytokines in nasal lavage fluid and splenocyte supernatants were analyzed.

RESULTS

IL-17A levels increased significantly more in ovalbumin-sensitized wild-type mice than in the negative control group. IL-17A-deficient mice showed a significant decrease in allergic symptoms, serum IgE levels, and eosinophil infiltration into the nasal mucosa compared with wild-type mice. IL-17A-deficient mice also showed decreased histamine and cysteinyl leukotriene release. Bone marrow-derived mast cells from IL-17A-deficient mice showed significantly lower degranulation and secretion of tumor necrosis factor α. Moreover, IL-17A deficiency attenuated the IL-5 level in nasal lavage fluid and its production in response to ovalbumin but did not increase interferon γ production and its level in nasal lavage fluid. In addition, secretion of IL-17A from spleen cells induced the expression of proinflammatory cytokine messenger RNA in macrophages. The mean level of proinflammatory cytokines, including tumor necrosis factor α and IL-17, decreased in IL-17A-deficient mice.

CONCLUSION

These results suggest that IL-17A may partly contribute to the development of nasal allergic inflammation in an AR animal model and regulate AR via the activation of proinflammatory cytokines and modulation of T(H)2 cytokine.

The E3 ubiquitin ligase adaptor Ndfip1 regulates Th17 differentiation by limiting the production of proinflammatory cytokines

Ndfip1 is an adaptor for the E3 ubiquitin ligase Itch. Both Ndfip1- and Itch-deficient T cells are biased toward Th2 cytokine production. In this study, we demonstrate that lungs from Ndfip1(-/-) mice showed increased numbers of neutrophils and Th17 cells. This was not because Ndfip1(-/-) T cells are biased toward Th17 differentiation. In fact, fewer Ndfip1(-/-) T cells differentiated into Th17 cells in vitro due to high IL-4 production. Rather, Th17 differentiation was increased in Ndfip1(-/-) mice due to increased numbers of IL-6-producing eosinophils. IL-6 levels in mice that lacked both Ndfip1 and IL-4 were similar to wild-type controls, and these mice had fewer Th17 cells in their lungs. These results indicate that Th2 inflammation, such as that observed in Ndfip1(-/-) mice, can increase Th17 differentiation by recruiting IL-6-producing eosinophils into secondary lymphoid organs and tissues. This may explain why Th17 cells develop within an ongoing Th2 inflammatory response.

Mechanisms of rapid induction of interleukin-22 in activated T cells and its modulation by cyclosporin a

IL-22 is an immunoregulatory cytokine displaying pathological functions in models of autoimmunity like experimental psoriasis. Understanding molecular mechanisms driving IL-22, together with knowledge on the capacity of current immunosuppressive drugs to target this process, may open an avenue to novel therapeutic options. Here, we sought to characterize regulation of human IL22 gene expression with focus on the established model of Jurkat T cells. Moreover, effects of the prototypic immunosuppressant cyclosporin A (CsA) were investigated. We report that IL-22 induction by TPA/A23187 (T/A) or αCD3 is inhibited by CsA or related FK506. Similar data were obtained with peripheral blood mononuclear cells or purified CD3(+) T cells. IL22 promoter analysis (-1074 to +156 bp) revealed a role of an NF-AT (-95/-91 nt) and a CREB (-194/-190 nt) binding site for gene induction. Indeed, binding of CREB and NF-ATc2, but not c-Rel, under the influence of T/A to those elements could be proven by ChIP. Because CsA has the capability to impair IκB kinase (IKK) complex activation, the IKKα/β inhibitor IKKVII was evaluated. IKKVII likewise reduced IL-22 induction in Jurkat cells and peripheral blood mononuclear cells. Interestingly, transfection of Jurkat cells with siRNA directed against IKKα impaired IL22 gene expression. Data presented suggest that NF-AT, CREB, and IKKα contribute to rapid IL22 gene induction. In particular the crucial role of NF-AT detected herein may form the basis of direct action of CsA on IL-22 expression by T cells, which may contribute to therapeutic efficacy of the drug in autoimmunity.

Plasma IL-6 and IL-9 predict the failure of interferon-α plus ribavirin therapy in HIV/HCV-coinfected patients

BACKGROUND

The cytokine profile plays an important role in treatment outcome of hepatitis C virus (HCV) infection, and probably modulates the immune response against HCV. The aim of this study was to evaluate which cytokines affect the response to interferon-α (IFN-α) and ribavirin therapy and how these cytokines change 72 weeks after starting anti-HCV therapy in HIV/HCV-coinfected patients.

METHODS

We carried out a retrospective follow-up study of 65 patients on anti-HCV therapy. A sustained virological response (SVR) was defined as an undetectable HCV viral load up to 24 weeks after the end of treatment. Cytokines were measured using a multiplex immunoassay kit.

RESULTS

On starting anti-HCV therapy, non-responder (NR) patients had higher levels of interleukin (IL)-6, IL-9, IL-10 and tumour necrosis factor (TNF)-α (P < 0.05), while IL-17A levels were increased in SVR patients (P = 0.058). However, only patients with high levels of IL-6 and IL-9 had decreased odds to achieve SVR (P < 0.05). Plasma levels of IL-6 and IL-9 had a high predictive value for SVR failure [area under the ROC curve (AUC) 0.839 (95% CI 0.733-0.945) and AUC 0.769 (95% CI 0.653-0.884)]. In addition, during anti-HCV therapy, IL-1β showed an increase in NR patients (P = 0.015) and IL-10 decreased in SVR patients (P = 0.049). After clearing HCV infection, low levels of TNF-α, IL-6, IL-9, IL-10, IL-13 and IL-22 were found in SVR patients (P < 0.05), as well as IL-1β, but only near statistical significance (P = 0.073).

CONCLUSIONS

High plasma levels of IL-6 and IL-9 had a high predictive value for SVR failure. Furthermore, clearing of HCV infection was associated with low inflammatory and T helper (Th)2/Th9/Th22 cytokine levels.

Dectin-1 is an extracellular pathogen sensor for the induction and processing of IL-1β via a noncanonical caspase-8 inflammasome

Production of the proinflammatory cytokine interleukin 1β (IL-1β) by dendritic cells is crucial in host defense. Here we identify a previously unknown role for dectin-1 in the activation of a noncanonical caspase-8 inflammasome in response to fungi and mycobacteria. Dectin-1 induced both the production and maturation of IL-1β through signaling routes mediated by the kinase Syk. Whereas the CARD9-Bcl-10-MALT1 scaffold directed IL1B transcription, the recruitment of MALT1-caspase-8 and ASC into this scaffold was crucial for processing of pro-IL-1β by caspase-8. In contrast to activation of the canonical caspase-1 inflammasome, which requires additional activation of cytosolic receptors, activation of the noncanonical caspase-8 inflammasome was independent of pathogen internalization. Thus, dectin-1 acted as an extracellular sensor for pathogens that induced both IL-1β production and maturation through a noncanonical caspase-8-dependent inflammasome for protective immunity.

The antimicrobial peptide hLF1-11 drives monocyte-dendritic cell differentiation toward dendritic cells that promote antifungal responses and enhance Th17 polarization

The hLF1-11 peptide comprising the first 11 N-terminal residues of human lactoferrin exerts antimicrobial activity in vivo, enhances the inflammatory response of monocytes and directs monocyte-macrophage differentiation toward cells with enhanced antimicrobial properties. In this study, we investigated the effects of hLF1-11 on human monocyte-dendritic cell (DC) differentiation and subsequent T cell activation. Results revealed that - compared to control (peptide-incubated) DCs - hLF1-11-differentiated DCs displayed enhanced expression of HLA class II antigens and dectin-1, and increased phagocytosis of Candida albicans. In addition, hLF1-11-differentiated DCs produced enhanced amounts of reactive oxygen species, IL-6 and IL-10, but not IL-12p40 and TNF-α, upon stimulation with C. albicans. Moreover, 6-day-cultured hLF1-11-differentiated DCs and control (peptide-incubated) DCs that had been stimulated with a Th17-inducing mix of antigens (including C. albicans) for 24 h were cocultured with autologous CD4+ T cells for 72 h and then the levels of IL-10, IL-17 and IFN-γ production and the percentage of cytokine-producing T cells were assessed. The results revealed that the hLF1-11-differentiated DCs induced an enhanced IL-17, but reduced IFN-γ, production by T cells as compared to control (peptide-incubated) DCs. Collectively, the hLF1-11 peptide drives monocyte-DC differentiation toward DCs that promote antifungal responses and enhance Th17 polarization.

Effector T-cell subsets in systemic lupus erythematosus: update focusing on Th17 cells

PURPOSE OF REVIEW

The discovery of T helper (Th)17 cells that produce the proinflammatory cytokine IL-17 has substantially advanced our understanding of T-cell biology and autoimmunity. We will review recent findings on effector T cells, in particular Th17 cells, in lupus.

RECENT FINDINGS

Studies reported increased IL-17 levels in the circulation and tissues in human and murine lupus. Patients with systemic lupus erythematosus (SLE or lupus) had an increased frequency of Th17 cells in peripheral blood which correlated with disease activity. However, the frequency of IFN-γ-producing Th1 cells did not change in the same patients, suggesting a selective dysregulation of Th17 cells in SLE. In addition, patients with SLE had an increased frequency of IL-17-producing CD3CD4CD8 (double negative) T cells in the peripheral blood and kidneys. Similar findings were noticed in lupus-prone MRL/MP-lpr/lpr (MRL/lpr) mice. A recent study demonstrated that IL-17 could promote B-cell survival and differentiation into antibody-producing cells. This raises the possibility that IL-17 is implicated in the pathogenesis of SLE by promoting humoral immunity against self-antigen.

SUMMARY

Emerging data show a body of evidence that IL-17 and Th17 cells may play a role in the pathogenesis of SLE. Further studies are warranted to dissect the mechanism for increased IL-17 production and the therapeutic implication of targeting this cytokine in SLE.

Low level of regulatory T cells and maintenance of balance between regulatory T cells and TH17 cells in HIV-1-infected elite controllers

BACKGROUND

A subgroup of HIV-1-infected individuals, elite controllers, have spontaneous viral control and offer an exceptional opportunity to study virological and immunolocigal factors of possible involvement in control of HIV-1 infection.

METHODS

The frequencies of Tregs and TH17 cells was evaluated and correlated to markers of disease progression in peripheral blood mononuclear cells from 3 different groups of individuals infected with HIV-1: treatment-naive viremic individuals, individuals on successful highly active antiretroviral therapy, and elite controllers. In addition, a group of HIV-1-negative individuals were included.

RESULTS

We demonstrate that elite controllers have lower levels of Tregs compared with HIV-1-infected viremic individuals, but that the low Treg level does not differ between individuals with HIV-1 control, whether natural or therapy induced. We also show that T-cell activation and proliferation both correlate to the level of Tregs. Finally, the TH17/Treg ratio was similar in Elite Controllers and uninfected controls, whereas in viremic and treated HIV-1-infected individuals, the TH17/Treg ratio was lower compared with uninfected controls.

CONCLUSIONS

We show that one feature of spontaneous HIV-1 control is a maintained balance between regulatory T cells and TH17 cells.

Mechanisms of subcutaneous allergen immunotherapy

Allergen-specific immunotherapy (SIT) is the only curative approach in the treatment of allergic diseases defined up-to-date. Peripheral T-cell tolerance to allergens, the goal of successful allergen-SIT, is the primary mechanism in healthy immune responses to allergens. By repeated administration of increased doses of the causative allergen, allergen-SIT induces a state of immune tolerance to allergens through the constitution of T regulatory (Treg) cells, including allergen-specific interleukin (IL)-10-secreting Treg type 1 cells and CD4(+)CD25(+)Treg cells; induction of suppressive cytokines, such as IL-10 and transforming growth factor β; suppression of allergen-specific IgE and induction of IgG4 and IgA; and suppression of mast cells, basophils, eosinophils, and inflammatory dendritic cells. This review summarizes the current knowledge on the mechanisms of allergen-SIT with emphasis on the roles of Treg cells in allergen-SIT.

The expression of Foxp3 and ROR gamma t in lung tissues from normal smokers and chronic obstructive pulmonary disease patients

Foxp3- and ROR gamma t-expressing cells are involved in acquired immune responses. The change in Foxp3 and ROR gamma t expression in lung tissue and their role in emphysema has not been studied for COPD patients and normal smokers. In the present study, Foxp3 and ROR gamma t were assessed using real-time quantitative polymerase chain reaction and western blotting, and the expression and distribution of Foxp3, IL-17, IL-23R and CCR6 were measured by immunohistochemistry in peripheral lung tissue (10 smokers with COPD, 10 smokers and 10 nonsmokers with normal lung function). Foxp3 expression was lower and ROR gamma t expression was higher in COPD patients when compared with smokers and nonsmokers (all P values were less than 0.001). The ratios of Foxp3/ROR gamma t mRNA and protein were positively correlated to FEV1%pred and negatively correlated to the mean alveoli area. Foxp3(+) cell numbers were decreased, while the number of IL-17(+) cells, IL-23R(+) cells and CCR6(+) cells were increased in the lung alveolar walls of COPD patients compared with normal smokers and nonsmokers (all P values were less than 0.001). The IL-17(+) cell numbers were positively correlated to both CCR6(+) and IL-23R(+) cells. Our data show a decreased Foxp3 expression and an increased ROR gamma t expression in COPD patients and normal smokers that parallels the aggravation of the disease. The IL-17(+)-cell-related cytokines receptors CCR6 and IL-23R had an association with the mechanism of IL-17(+) cell number increasing, which will provide a new immuno-therapeutic target for COPD.

Gut derived lactic acid bacteria induce strain specific CD4(+) T cell responses in human PBMC

BACKGROUND & AIMS

Probiotic bacteria are used as food supplement in many different disease settings. The immune modulating capacity of different strains is not always properly tested which might result in a suboptimal choice of strains for clinical use.

METHODS

The CD4 T cell responses to 19 different gut derived lactic acid bacteria were tested with different methods to show their diversity in immune modulation and to make a well-founded choice on which strains to use in future clinical trials. After co-culture of PBMC with bacteria, the induction of CD4(+) T cell subsets (regulatory T cells, T helper type (TH)1, TH2 and TH17) was analysed by rtPCR of transcription factor mRNA, intracellular FACS staining of transcription factors and cytokine production.

RESULTS

Bacterial strains all have diverse, unique immune modulatory properties. Strains can induce Treg, TH1, TH2 and TH17 cells which can be shown at different levels of T cell activation, and is consistent for most strains tested. For TH1, TH17 and Treg, a positive correlation between the different methods was found. For TH2 cells the correlation was less consistent.

CONCLUSIONS

Probiotic bacteria have very different immune modulating capacities. Analysis of transcription factor mRNA is a suitable method for in vitro characterization of strains prior to clinical application.

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.

Immuno-modulatory activity of Ganoderma lucidum-derived polysacharide on human monocytoid dendritic cells pulsed with Der p 1 allergen

Background

Ganoderma lucidum-derived polysaccharide (PS-G) can rapidly and effectively promote the activation and maturation of immature dendritic cells (DCs), suggesting that PS-G possesses the capacity to regulate immune responses. This study aimed to clarify the immunologic effect of PS-G on monocyte-derived dendritic cells (MD-DCs) from asthmatic children allergic to house dust mites. The MD-DCs were stimulated for 24 h with the related allergen, Der p 1, in the presence or absence of PS-G. Cell surface markers and phagocytic capacity were assessed by FACS analysis, and key polarizing cytokines (IL-12 p40, IL-12 p70, IL-6, IL-23, and IL-10) were quantified. The subsequent regulatory effect of pulsed MD-DCs on naïve T cells was evaluated by determining the T-cell cytokine profile.

Results

PS-G induced the maturation of MD-DCs and decreased phagocytic capacity, even if pulsed with Der p 1. After incubation with PS-G and Der p 1, MD-DCs produced higher amounts of IL-12 p70, IL-12 p40, IL-6, IL-23, and IL10 than Der p 1-pulsed DCs. Furthermore, type 1 helper T (Th1) cell cytokine (INF-γ) production was highly increased when naïve autologous T cells were co-cultured with Der p 1-pulsed MD-DCs. Naïve T cells stimulated by MD-DCs pulsed with Der p 1 failed to produce proliferation of T-cells, whereas the addition of PS-G to Der p 1 induced a significant proliferation of T-cells similar to that observed with PS-G alone.

Conclusion

The presence of PS-G in an allergen pulse promoted allergic MD-DCs to produce IL-12 p70, IL-12 p40, IL-6, IL-23, and IL-10, and exerted an effect on shifting the immune balance towards Th1 in children with allergic asthma.

Immunotherapy in asthma

Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. Chronic inflammation is associated with airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness and coughing, as well as variable airflow obstruction within the lung. With time, such airflow obstruction may become permanent due to remodeling. It has been treated for more than 100 years by subcutaneous immunotherapy with allergen extracts but in recent years, other forms and types of immunotherapy have been introduced. Perhaps the most successful of these to date, is sublingual immunotherapy, which has attained significant usage in European countries but has yet to make inroads into clinical practice in North America. Other mechanisms to modify the inflammatory responses of asthma have included immunotherapy with recombinant allergens, the use of allergen peptides targeting antigen-specific T cells and the administration of Toll-like receptor agonists coupled to allergen proteins. As the inflammatory responses in asthma frequently involve IgE, a modified monoclonal antibody to IgE and interfering with its binding to the IgE receptor have gained acceptance for treating severe allergic asthma. Other monoclonal antibodies or recombinant receptor antagonists are being assessed for their ability to block other contributors to the inflammatory response. Finally, attempts have been made to generate autoantibody responses to cytokines implicated in asthma. Most of these therapies aim to modify or inhibit the so-called Th 2 immune response, which is implicated in many forms of asthma, or to inhibit cytokines involved in these responses. However, an added benefit of classical immunotherapy seems to be the ability to prevent the allergic progression to new sensitivities and new forms of allergic disease.

Vitamin D and asthma

PURPOSE OF REVIEW

asthma is a disease that continues to carry a significant health burden on humanity. Vitamin D is thought to play a role in many chronic diseases as it may possess immunomodulatory properties. This article will review the role of vitamin D regulation on the immune system and its potential implication in the pathophysiology of asthma.

RECENT FINDINGS

vitamin D receptors are present on many cells in the body, specifically peripheral blood mononuclear cells. Vitamin D has been shown to regulate the balance of several pro-inflammatory and anti-inflammatory responses in the immune system. Studies have suggested that prenatal vitamin D intake has an effect on childhood wheezing and asthma. Additionally, vitamin D may play a role in asthma exacerbations, and recent evidence also suggests its importance in steroid resistant asthma.

SUMMARY

vitamin D has a complex role on the immune system and its regulation of various aspects of immunity has allowed speculation on its potential role in asthma. However, the net effect of vitamin D on the immune system and its role in asthma still remains unanswered. More research needs to address the diagnostic and therapeutic implications vitamin D may have in the future of asthma management.

Osteopontin and allergic disease: pathophysiology and implications for diagnostics and therapy

Osteopontin (OPN) is a phosphoglycoprotein that is expressed by various immune cells in a secreted and intracellular form. It has cytokine, chemotactic and cell signaling functions enhancing Th1 and Th17 immunity and protects against apoptosis. Recent studies found OPN to be modulatory in cell-mediated and immediate-type allergic diseases. In allergic asthma, OPN enhances sensitization but downmodulates Th2-driven IL-4-dominated inflammation. The finding that OPN expression is augmented during specific immunotherapy supports a Th2 suppressive effect of OPN. In Th1-driven delayed-type allergy, such as allergic contact dermatitis, OPN supports dendritic cell migration and IL-12 expression and is secreted by T effector cells and keratinocytes, augmenting Th1-mediated allergy and supporting disease chronification. There are numerous missing links as to how OPN variants modulate allergic inflammation through different OPN receptors. OPN research in allergy is an interesting, rapidly expanding field that has high potential for translational research.

The TLR7 ligand 9-benzyl-2-butoxy-8-hydroxy adenine inhibits IL-17 response by eliciting IL-10 and IL-10-inducing cytokines

This study evaluates the ability of a novel TLR7 ligand (9-benzyl-2-butoxy-8-hydroxy adenine, called SA-2) to affect IL-17 response. The SA-2 activity on the expression of IL-17A and IL-17-related molecules was evaluated in acute and chronic models of asthma as well as in in vivo and in vitro α-galactosyl ceramide (α-GalCer)-driven systems. SA-2 prepriming reduced neutrophils in bronchoalveolar lavage fluid and decreased methacoline-induced airway hyperresponsiveness in murine asthma models. These results were associated with the reduction of IL-17A (and type 2 cytokines) as well as of molecules favoring Th17 (and Th2) development in lung tissue. The IL-17A production in response to α-GalCer by spleen mononuclear cells was inhibited in vitro by the presence of SA-2. Reduced IL-17A (as well as IFN-γ and IL-13) serum levels in mice treated with α-GalCer plus SA-2 were also observed. The in vitro results indicated that IL-10 produced by B cells and IL-10-promoting molecules such as IFN-α and IL-27 by dendritic cells are the major player for SA-2-driven IL-17A (and also IFN-γ and IL-13) inhibition. The in vivo experiments with anti-cytokine receptor Abs provided evidence of an early IL-17A inhibition essentially due to IL-10 produced by resident peritoneal cells and of a delayed IL-17A inhibition sustained by IFN-α and IL-27, which in turn drive effector T cells to IL-10 production. These findings suggest that such TLR7 agonist downregulating Th17 (as well as Th2) response has to be considered a valid candidate for novel vaccine formulations in allergy.

Joining the immunological dots in recurrent miscarriage

While raised cellular immunity mediated by T helper (Th) 1 type cells may be harmful for the developing embryo/foetus, it is likely that Th2 type immunity may be helpful. The role of natural killer (NK) cells is presently underestimated, although they are clearly important in angiogenesis and the coordinated invasion of the decidua by the trophoblast. Deficient T regulatory cell (Treg) function is evident in women with recurrent miscarriage particularly when this occurs in early pregnancy. The role of the pro-inflammatory Th17 cells is presently unclear. However, early evidence suggests that excessive Th17 activity may promote miscarriage and preterm delivery. This may relate to the ability of these cells to produce those cytokines that encourage Th1 and NK cell activity. As such recurrent miscarriage may be caused not only by chromosomal abnormalities, autoimmunity and uterine abnormalities but also by subclinical uterine infection and inflammation which by stimulating interleukin 6 favours Th17 development over Tregs. This review examines the role of these different cells in early pregnancy and suggests a schema that may join the dots of the immunological puzzle called pregnancy. Finally, suggestions are made as to how inappropriate immunity in recurrent miscarriage may be down-regulated using currently available therapies.

Inducible NO synthase and antibacterial host defence in times of Th17/Th22/T22 immunity

During the last two decades nitric oxide (NO) produced by inducible NO synthase (iNOS or NOS2) has been characterized as immunoregulatory and antimicrobial principle displaying the potential to determine course of disease in a range of infections. Being an enzyme primarily regulated on expressional level, cytokine-driven iNOS appears to be connected in particular with activation of Th1-type immunity. However, with the recent advent of additional, partly overlapping CD4(+) T cell effector subsets, namely Th17 and Th22 cells, a further layer of complexity has been added to immunoregulatory networks determining inflammatory gene expression in the context of microbial infections. Here, we review current knowledge on activation of iNOS function by interleukin (IL)-17 and IL-22 with focus on Th17/Th22-directed antibacterial immunity.

Role of inducible nitric oxide synthase on the development of virus-associated asthma exacerbation which is dependent on Th1 and Th17 cell responses

Asthma is characterized by airway inflammation induced by immune dysfunction to inhaled antigens. Although respiratory viral infections are the most common cause of asthma exacerbation, immunologic mechanisms underlying virus-associated asthma exacerbation are controversial. Clinical evidence indicates that nitric oxide (NO) levels in exhaled air are increased in exacerbated asthma patients compared to stable patients. Here, we evaluated the immunologic mechanisms and the role of NO synthases (NOSs) in the development of virus-associated asthma exacerbation. A murine model of virus-associated asthma exacerbation was established using intranasal challenge with ovalbumin (OVA) plus dsRNA for 4 weeks in mice sensitized with OVA plus dsRNA. Lung infiltration of inflammatory cells, especially neutrophils, was increased by repeated challenge with OVA plus dsRNA, as compared to OVA alone. The neutrophilic inflammation enhanced by dsRNA was partly abolished in the absence of IFN-gamma or IL-17 gene expression, whereas unaffected in the absence of IL-13. In terms of the roles of NOSs, dsRNA-enhanced neutrophilic inflammation was significantly decreased in inducible NOS (iNOS)-deficient mice compared to wild type controls; in addition, this phenotype was inhibited by treatment with a non-specific NOS inhibitor (L-NAME) or an specific inhibitor (1400 W), but not with a specific endothelial NOS inhibitor (AP-CAV peptide). Taken together, these findings suggest that iNOS pathway is important in the development of virus-associated exacerbation of neutrophilic inflammation, which is dependent on both Th1 and Th17 cell responses.

Identification of Baicalin as an immunoregulatory compound by controlling T(H)17 cell differentiation

T_H17 cells have been implicated in a growing list of inflammatory disorders. Antagonism of T_H17 cells can be used for the treatment of inflammatory injury. Currently, very little is known about the natural compound controlling the differentiation of T_H17 cells. Here, we showed that Baicalin, a compound isolated from a Chinese herb, inhibited T_H17 cell differentiation both in vitro and in vivo. Baicalin might inhibit newly generated T_H17 cells via reducing RORγt expression, and together with up-regulating Foxp3 expression to suppress RORγt-mediated IL-17 expression in established T_H17 cells. In vivo treatment with Baicalin could inhibit T_H17 cell differentiation, restrain T_H17 cells infiltration into kidney, and protect MRL/lpr mice against nephritis. Our findings not only demonstrate that Baicalin could control T_H17 cell differentiation but also suggest that Baicalin might be a promising therapeutic agent for the treatment of T_H17 cells-mediated inflammatory diseases.

Selective C-Rel activation via Malt1 controls anti-fungal T(H)-17 immunity by dectin-1 and dectin-2

C-type lectins dectin-1 and dectin-2 on dendritic cells elicit protective immunity against fungal infections through induction of T_H1 and T_H-17 cellular responses. Fungal recognition by dectin-1 on human dendritic cells engages the CARD9-Bcl10-Malt1 module to activate NF-κB. Here we demonstrate that Malt1 recruitment is pivotal to T_H-17 immunity by selective activation of NF-κB subunit c-Rel, which induces expression of T_H-17-polarizing cytokines IL-1β and IL-23p19. Malt1 inhibition abrogates c-Rel activation and T_H-17 immunity to Candida species. We found that Malt1-mediated activation of c-Rel is similarly essential to induction of T_H-17-polarizing cytokines by dectin-2. Whereas dectin-1 activates all NF-κB subunits, dectin-2 selectively activates c-Rel, signifying a specialized T_H-17-enhancing function for dectin-2 in anti-fungal immunity by human dendritic cells. Thus, dectin-1 and dectin-2 control adaptive T_H-17 immunity to fungi via Malt1-dependent activation of c-Rel.

Fungal infections are a major health threat and the incidence is growing worldwide. There is a need for efficient antifungal vaccines. Adaptive immune responses and in particular T helper cell type 17 (T_H-17) responses are crucial in the defence against fungal infections. Human dendritic cells (DCs) induce T_H-17 responses after interaction with fungi. DCs express C-type lectins dectin-1 and dectin-2 that interact with the carbohydrate structures present in the cell-wall of fungi. It is unclear how signaling by these C-type lectins leads to specific T_H-17 responses. Here we demonstrate that the signaling molecule Malt1 present in the CARD9-Bcl10-Malt1 complex is responsible for T_H-17 induction by selectively activating the NF-κB transcription factor c-Rel, which drives transcription of the T_H-17-polarizing cytokines. Inhibition of either Malt1 or c-Rel prevents T_H-17 induction in response to fungi. Furthermore, we show that the C-type lectin dectin-2 selectively activates c-Rel, signifying a specialized T_H-17-enhancing function for this C-type lectin. Thus, novel vaccination strategies that target dectin-2 or activate Malt1 can induce predominant T_H-17 responses. Since aberrant T_H-17 responses underlie the pathology of atopic dermatitis and various autoimmune diseases, Malt1 is a rational therapeutic target to attenuate anomalous adaptive immune responses.

[Natural history of atopic dermatitis-outside-inside-outside story-]

In this review, I summarized recent studies about nonatopic dermatitis, IgE associated atopic dermatitis and autoallergic atopic dermatitis in the natural history of atopic dermatitis with gene -gene and gene -environment interaction. Also, new hypothesis of the mechanism of atopic dermatitis which was called OUTSIDE-INSIDE-OUTSIDE story wes introduced.

Forkhead box P3+ T cells express interleukin-17 in nasal mucosa of patients with both allergic rhinitis and polyposis

The pathogenesis of nasal polyposis remains unclear; it severely affects patients' quality of life and complicates inflammation in adjacent organs such as sinusitis and asthma. Aberrant immune regulatory function in these patients is proposed. The present study aims to examine the regulatory T cells (T(reg) ) in nasal mucosa of patients with allergic rhinitis (AR) and nasal polyposis (NP). Patients with AR or AR/NP were treated with inferior turbinectomy for their inferior turbinate hyperplasia. Surgically removed nasal mucosa was collected to examine the T(reg) by immunohistochemistry and flow cytometry. The results showed that more forkhead box P3 (FoxP3)(+) cells were found in AR with polyps than in those with AR alone. Further studies revealed that these FoxP3(+) T cells from AR/NP group also expressed interleukin (IL)-17. In vitro study showed that staphylococcal enterotoxin B (SEB) induced CD4(+) FoxP3(+) T cells to become FoxP3(+) IL-17(+) cells via facilitating the expression of IL-6, that in synergy with transforming growth factor-beta, induce the expression of IL-17 in FoxP3(+) cells. We conclude that FoxP3(+) IL-17(+) T cells were localized in the nasal mucosa of patients with AR and NP. SEB may play a role in converting FoxP3(+) T(reg) to FoxP3(+) IL-17(+) T cells. The presence of IL-17(+) FoxP3(+) T cells may play a role in the remodelling of the nasal airways in certain people who develop polyps, irrespective of whether or not they are atopic.

T(H)2 heterogeneity: Does function follow form?

T(H)2 immune responses are required for the 2 fundamental pathological processes characteristic of allergic disease: IgE-mediated hypersensitivity and eosinophilic inflammation. The 3 established T(H)2 cytokines, IL-4, IL-5, and IL-13, each play a nonredundant role in allergic disease pathology. The recent explosion of T(H) subpopulations combined with the wide availability of polychromatic cytokine staining has facilitated the discovery of T(H)2 lineage heterogeneity. In this article we review T(H)2 heterogeneity and ask the following question: At what point do these subpopulations graduate from in vitro curiosities to immunologically robust therapeutic targets? We propose criteria to establish a T-cell subset as a biologically relevant entity and address the evidence to support these T(H)2 subpopulations having a unique function or specific contribution to allergic pathology or host defense.

Early production of IL-22 but not IL-17 by peripheral blood mononuclear cells exposed to live Borrelia burgdorferi: the role of monocytes and interleukin-1

If insufficiently treated, Lyme borreliosis can evolve into an inflammatory disorder affecting skin, joints, and the CNS. Early innate immunity may determine host responses targeting infection. Thus, we sought to characterize the immediate cytokine storm associated with exposure of PBMC to moderate levels of live Borrelia burgdorferi. Since Th17 cytokines are connected to host defense against extracellular bacteria, we focused on interleukin (IL)-17 and IL-22. Here, we report that, despite induction of inflammatory cytokines including IL-23, IL-17 remained barely detectable in response to B. burgdorferi. In contrast, T cell-dependent expression of IL-22 became evident within 10 h of exposure to the spirochetes. This dichotomy was unrelated to interferon-γ but to a large part dependent on caspase-1 and IL-1 bioactivity derived from monocytes. In fact, IL-1β as a single stimulus induced IL-22 but not IL-17. Neutrophils display antibacterial activity against B. burgdorferi, particularly when opsonized by antibodies. Since neutrophilic inflammation, indicative of IL-17 bioactivity, is scarcely observed in Erythema migrans, a manifestation of skin inflammation after infection, protective and antibacterial properties of IL-22 may close this gap and serve essential functions in the initial phase of spirochete infection.

Host defense mechanisms in secondary syphilitic lesions: a role for IFN-gamma-/IL-17-producing CD8+ T cells?

Cell-mediated immunity is thought to be of critical importance in antisyphilitic host defense, but the exact mechanisms are still unknown. This fact is particularly true for HIV-infected persons with a deficit in CD4+ T-cell number. We therefore obtained lesional skin samples from HIV+ and HIV- patients with secondary syphilis at different time points of lesional age to search both for causative microorganisms and to characterize the inflammatory infiltrate. By doing so, we detected Treponema pallidum spirochetes with a much greater abundance in late lesions of HIV+ individuals compared with the HIV- cohort. The dominating inflammatory cells were T cells, macrophages, and neutrophils at all stages and plasma cells in older lesions. In HIV- persons, T cells consisted of equal numbers of CD4+ and CD8+ T-cells, whereas in HIV+ patients, the majority of T cells belonged to the CD8 lineage and produced both IFN-γ and IL-17. Regulatory T cells and Langerhans cells were reduced in these patients compared with their HIV- counterparts. Because of our observations, we propose that T cells of both the CD4 and CD8 lineage are needed for an at least partial protective antisyphilitic immunity. Compensation mechanisms in HIV+ individuals, such as an increase of Tc1/17 cells as well as a reduction in immunoregulatory Langerhans cells and T cells, apparently do not overcome the deficiencies in these patients to eliminate the spirochete.

A formal analysis of cytokine networks in chronic fatigue syndrome

Chronic Fatigue Syndrome (CFS) is a complex illness affecting 4 million Americans for which no characteristic lesion has been identified. Instead of searching for a deficiency in any single marker, we propose that CFS is associated with a profound imbalance in the regulation of immune function forcing a departure from standard pre-programmed responses. To identify these imbalances we apply network analysis to the co-expression of 16 cytokines in CFS subjects and healthy controls. Concentrations of IL-1a, 1b, 2, 4, 5, 6, 8, 10, 12, 13, 15, 17 and 23, IFN-γ, lymphotoxin-α (LT-α) and TNF-α were measured in the plasma of 40 female CFS and 59 case-matched controls. Cytokine co-expression networks were constructed from the pair-wise mutual information (MI) patterns found within each subject group. These networks differed in topology significantly more than expected by chance with the CFS network being more hub-like in design. Analysis of local modularity isolated statistically distinct cytokine communities recognizable as pre-programmed immune functional components. These showed highly attenuated Th1 and Th17 immune responses in CFS. High Th2 marker expression but weak interaction patterns pointed to an established Th2 inflammatory milieu. Similarly, altered associations in CFS provided indirect evidence of diminished NK cell responsiveness to IL-12 and LT-α stimulus. These observations are consistent with several processes active in latent viral infection and would not have been uncovered by assessing marker expression alone. Furthermore this analysis identifies key sub-networks such as IL-2:IFN-γ:TNF-α that might be targeted in restoring normal immune function.

Stimulation of lymphangiogenesis via VEGFR-3 inhibits chronic skin inflammation

The role of lymphangiogenesis in inflammation has remained unclear. To investigate the role of lymphatic versus blood vasculature in chronic skin inflammation, we inhibited vascular endothelial growth factor (VEGF) receptor (VEGFR) signaling by function-blocking antibodies in the established keratin 14 (K14)-VEGF-A transgenic (Tg) mouse model of chronic cutaneous inflammation. Although treatment with an anti-VEGFR-2 antibody inhibited skin inflammation, epidermal hyperplasia, inflammatory infiltration, and angiogenesis, systemic inhibition of VEGFR-3, surprisingly, increased inflammatory edema formation and inflammatory cell accumulation despite inhibition of lymphangiogenesis. Importantly, chronic Tg delivery of the lymphangiogenic factor VEGF-C to the skin of K14-VEGF-A mice completely inhibited development of chronic skin inflammation, epidermal hyperplasia and abnormal differentiation, and accumulation of CD8 T cells. Similar results were found after Tg delivery of mouse VEGF-D that only activates VEGFR-3 but not VEGFR-2. Moreover, intracutaneous injection of recombinant VEGF-C156S, which only activates VEGFR-3, significantly reduced inflammation. Although lymphatic drainage was inhibited in chronic skin inflammation, it was enhanced by Tg VEGF-C delivery. Together, these results reveal an unanticipated active role of lymphatic vessels in controlling chronic inflammation. Stimulation of functional lymphangiogenesis via VEGFR-3, in addition to antiangiogenic therapy, might therefore serve as a novel strategy to treat chronic inflammatory disorders of the skin and possibly also other organs.