Th9 cells, new players in adaptive immunity

Emerging Roles of Th9 Cells as an Anti-tumor Helper T Cells

The newly discovered Th9 cells are the distinct subset of CD4⁺ T helper (Th) cells, which are involved in various pathophysiological conditions of an immune response. In addition to its role in allergic inflammation and elimination of extracellular pathogens, Th9 cells were found to play a key role in inducing anti-tumor immune response. Precisely, the anti-tumor functions of Th9 cells were found to be superior as compared to Th1 and other Th subsets. Th9 cells eliminate tumors via activating innate and adaptive immune cells, and in particular, generating a profound effector cytotoxic T lymphocyte (CTL) response against neo antigens. In addition, it was proposed that Th9 cells were found to induce effector functions of innate cells like dendritic cells, mast cells and NK cells, which further promote a robust anti-tumor immune response. In this review, we highlight the recent advances in differentiation and functions of Th9 cells in anti-tumor immunity.

The connection between the Th17 cell related cytokines and cancer stem cells in cancer: Novel therapeutic targets

Cancer Stem Cells (CSCs) are the subpopulation of cells present in the different types of cancers with capabilities of self-renewal, differentiation, and tumorigenicity when transplanted into an animal host. The research work on the CSC has been providing a promising approach for the improvement of cancer therapies in the future. The CSCs have a close connection with the cytokines related with the T helper 17 (Th17) cell and other factors present in the tumor microenvironment, and these play a pivotal role in tumor progression and metastasis. The properties of CSCs are well defined in various type of tumor which is mainly developed by chemically and spontaneously in murine cancer model but in human defined primarily on acute myeloid leukemia, glioma, and breast cancer. The role of Th1, Th2, Natural Killer cells are well described in the cancer biology, but the Th17 cells are the subset which is recently exploited, and lots of research are going on. In this Review, we summarize current findings of the characteristics and functions of the Th17 cell and its signature cytokines in different cancers and their interconnections with cancer stem cells and with their markers. We have also discussed the functional properties of CSCs and how the CSCs markers can be distinguished from normal stem cells markers. We have also talked about the strategies that are efficiently targeting of CSCs and Th17 cells in different cancers.

The amino acid sensor general control nonderepressible 2 (GCN2) controls TH9 cells and allergic airway inflammation

BACKGROUND

T_H9 cells have emerged as important mediators of allergic airway inflammation. There is evidence that general control nonderepressible 2 (GCN2) affects the immune response under some stress conditions. However, whether GCN2 regulates CD4⁺ T-cell differentiation during allergic inflammation remains unknown.

OBJECTIVE

We sought to clarify the regulatory roles of GCN2 in CD4⁺ T-cell subset differentiation and its significance in patients with allergic airway inflammation.

METHODS

The effects of GCN2 in differentiation of T_H cell subsets were detected by using the in vitro induction system. GCN2 knockout mice, ovalbumin-induced allergic airway inflammation, and adoptive transfer mouse models were used to determine the significance of GCN2 in T_H9 differentiation and allergic airway inflammation in vivo. RNA sequencing, real-time PCR, Western blotting, and other molecular approaches were used to identify the molecular mechanisms relevant to regulation of GCN2 in T_H9 cell differentiation.

RESULTS

GCN2 deficiency significantly inhibited differentiation of T_H9 cells but not T_H1, T_H2, and regulatory T cells. GCN2 knockout mice and recombination-activating gene 2 knockout (Rag2KO) mice that received adoptively transferred GCN2-deficient CD4⁺ T cells exhibited reduced T_H9 differentiation and less severe allergic airway inflammation. Furthermore, the isolated GCN2-deficient T_H9 cells also mediated less severe allergic airway inflammation on adoptive transfer. Mechanistically, GCN2 deficiency inhibits T_H9 cell differentiation through a hypoxia-inducible factor 1α-dependent glycolytic pathway.

CONCLUSION

Our results reveal a novel role of GCN2 in T_H9 cell differentiation. Our findings indicate that new strategies to inhibit GCN2 activity might provide novel approaches to attenuate allergic airway inflammation.

Metabolism in Immune Cell Differentiation and Function

The immune system is a central determinant of organismal health. Functional immune responses require quiescent immune cells to rapidly grow, proliferate, and acquire effector functions when they sense infectious agents or other insults. Specialized metabolic programs are critical regulators of immune responses, and alterations in immune metabolism can cause immunological disorders. There has thus been growing interest in understanding how metabolic processes control immune cell functions under normal and pathophysiological conditions. In this chapter, we summarize how metabolic programs are tuned and what the physiological consequences of metabolic reprogramming are as they relate to immune cell homeostasis, differentiation, and function.

The Role of Interleukin-9 in Cancer

Interluekin-9 (IL-9) is produced predominantly by helper T cells such as Th2 and Th9 cells. It normally functions through the activation of a JAK/STAT pathway and plays a critical role in immunity and the pathogenesis of cancer. In cancer, it yields different responses depending on the cancer cell line involved. This review is a summary of what is known about the involvement of IL-9 in various cancer cell lines as well as its role in immunity with a focus on allergic responses.

Hide and seek: Plasticity of innate lymphoid cells in cancer

The advance of immunotherapies has revolutionized the treatment of cancer patients. Mostly agents modulating the adaptive immune system are currently used. More recently, attempts to stimulate the innate immune system are being promoted for clinical evaluation. Innate lymphoid cells (ILCs) are a highly plastic population of immune cells crucial for tissue homeostasis and the regulation of immune responses and maybe a promising target to improve current cancer immunotherapies. Although we have made significant progress in understanding ILC biology, their impact on tumor development, progression and therapy is controversial. In this review, we discuss the recent advances of ILC function and plasticity in the context of cancer.

Stimulation of histamine H4 receptors increases the production of IL-9 in Th9 polarized cells

BACKGROUND AND PURPOSE

Th9 cells represent a recently defined subset of CD4⁺ T-helper cells, characterized by a high production of IL-9. They are found at increased frequency in lesions of atopic dermatitis, where IL-9 is also elevated. As histamine is up-regulated in lesions of inflammatory skin diseases, we investigated the expression profile of histamine receptors and their functional role on Th9 cells.

EXPERIMENTAL APPROACH

Naïve CD4⁺ T-cells were purified from human peripheral blood mononuclear cells, using magnetic beads and further differentiated into Th9 cells. During differentiation, cells were additionally stimulated with histamine receptor agonists or left untreated. Histamine receptor expression as well as IL-9 production was measured.

KEY RESULTS

As proof of a successful differentiation, IL-9 production was measured at mRNA and protein level. Expression of mRNA for histamine H₁ , H₂ and H₄ receptors were up-regulated in differentiated Th9 cells compared to Th0 cells, while no mRNA for the H₃ receptor was detectable. Stimulation of Th9 cells with histamine significantly up-regulated expression of mRNA and protein for IL-9 . Experiments with specific histamine receptor agonists and antagonists revealed that this up-regulation was mediated by H₄ receptors.

CONCLUSIONS AND IMPLICATIONS

In summary, our study demonstrates a functional role for histamine H₄ receptors on Th9 cells, which might amplify the pro-inflammatory potency of these cells. Together with earlier studies on Th2 and Th17 cells, this study underlines the promising approach for the use of H₄ receptor antagonists in inflammatory and allergic diseases such as atopic dermatitis.

LINKED ARTICLES

This article is part of a themed section on New Uses for 21st Century. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.3/issuetoc.

GM-CSF Promotes Antitumor Immunity by Inducing Th9 Cell Responses

GM-CSF as an adjuvant has been shown to promote antitumor immunity in mice and humans; however, the underlying mechanism of GM-CSF-induced antitumor immunity remains incompletely understood. In this study, we demonstrate that GM-CSF potentiates the efficacy of cancer vaccines through IL9-producing Th (Th9) cells. GM-CSF selectively enhanced Th9 cell differentiation by regulating the COX2-PGE₂ pathway while inhibiting the differentiation of induced regulatory T (iTreg) cells in vitro and in vivo GM-CSF-activated monocyte-derived dendritic cells converted tumor-specific naïve Th cells into Th9 cells, and delayed tumor growth by inducing antitumor CTLs in an IL9-dependent manner. Our findings reveal a mechanism for the adjuvanticity of GM-CSF and provide a rationale for the use of GM-CSF in cancer vaccines.

Phylotranscriptomics suggests the jawed vertebrate ancestor could generate diverse helper and regulatory T cell subsets

BACKGROUND

The cartilaginous fishes diverged from other jawed vertebrates ~ 450 million years ago (mya). Despite this key evolutionary position, the only high-quality cartilaginous fish genome available is for the elephant shark (Callorhinchus milii), a chimaera whose ancestors split from the elasmobranch lineage ~ 420 mya. Initial analysis of this resource led to proposals that key components of the cartilaginous fish adaptive immune system, most notably their array of T cell subsets, was primitive compared to mammals. This proposal is at odds with the robust, antigen-specific antibody responses reported in elasmobranchs following immunization. To explore this discrepancy, we generated a multi-tissue transcriptome for small-spotted catshark (Scyliorhinus canicula), a tractable elasmobranch model for functional studies. We searched this, and other newly available sequence datasets, for CD4+ T cell subset-defining genes, aiming to confirm the presence or absence of each subset in cartilaginous fishes.

RESULTS

We generated a new transcriptome based on a normalised, multi-tissue RNA pool, aiming to maximise representation of tissue-specific and lowly expressed genes. We utilized multiple transcriptomic datasets and assembly variants in phylogenetic reconstructions to unambiguously identify several T cell subset-specific molecules in cartilaginous fishes for the first time, including interleukins, interleukin receptors, and key transcription factors. Our results reveal the inability of standard phylogenetic reconstruction approaches to capture the site-specific evolutionary processes of fast-evolving immune genes but show that site-heterogeneous mixture models can adequately do so.

CONCLUSIONS

Our analyses reveal that cartilaginous fishes are capable of producing a range of CD4+ T cell subsets comparable to that of mammals. Further, that the key molecules required for the differentiation and functioning of these subsets existed in the jawed vertebrate ancestor. Additionally, we highlight the importance of considering phylogenetic diversity and, where possible, utilizing multiple datasets for individual species, to accurately infer gene presence or absence at higher taxonomic levels.

Protein Tyrosine Phosphatases: Regulators of CD4 T Cells in Inflammatory Bowel Disease

Protein tyrosine phosphatases (PTPs) play a critical role in co-ordinating the signaling networks that maintain lymphocyte homeostasis and direct lymphocyte activation. By dephosphorylating tyrosine residues, PTPs have been shown to modulate enzyme activity and both mediate and disrupt protein-protein interactions. Through these molecular mechanisms, PTPs ultimately impact lymphocyte responses to environmental cues such as inflammatory cytokines and chemokines, as well as antigenic stimulation. Mouse models of acute and chronic intestinal inflammation have been shown to be exacerbated in the absence of PTPs such as PTPN2 and PTPN22. This increase in disease severity is due in part to hyper-activation of lymphocytes in the absence of PTP activity. In accordance, human PTPs have been linked to intestinal inflammation. Genome wide association studies (GWAS) identified several PTPs within risk loci for inflammatory bowel disease (IBD). Therapeutically targeting PTP substrates and their associated signaling pathways, such as those implicated in CD4⁺ T cell responses, has demonstrated clinical efficacy. The current review focuses on the role of PTPs in controlling CD4⁺ T cell activity in the intestinal mucosa and how disruption of PTP activity in CD4⁺ T cells can contribute to intestinal inflammation.

Integrating Immunology and Microfluidics for Single Immune Cell Analysis

The field of immunoengineering aims to develop novel therapies and modern vaccines to manipulate and modulate the immune system and applies innovative technologies toward improved understanding of the immune system in health and disease. Microfluidics has proven to be an excellent technology for analytics in biology and chemistry. From simple microsystem chips to complex microfluidic designs, these platforms have witnessed an immense growth over the last decades with frequent emergence of new designs. Microfluidics provides a highly robust and precise tool which led to its widespread application in single-cell analysis of immune cells. Single-cell analysis allows scientists to account for the heterogeneous behavior of immune cells which often gets overshadowed when conventional bulk study methods are used. Application of single-cell analysis using microfluidics has facilitated the identification of several novel functional immune cell subsets, quantification of signaling molecules, and understanding of cellular communication and signaling pathways. Single-cell analysis research in combination with microfluidics has paved the way for the development of novel therapies, point-of-care diagnostics, and even more complex microfluidic platforms that aid in creating in vitro cellular microenvironments for applications in drug and toxicity screening. In this review, we provide a comprehensive overview on the integration of microsystems and microfluidics with immunology and focus on different designs developed to decode single immune cell behavior and cellular communication. We have categorized the microfluidic designs in three specific categories: microfluidic chips with cell traps, valve-based microfluidics, and droplet microfluidics that have facilitated the ongoing research in the field of immunology at single-cell level.

Th17 response in patients with cervical cancer

Persistent infection by high-risk human papillomavirus (HR-HPV) is the main risk factor for uterine cervical cancer (UCC). However, viral infection alone is not sufficient for the development and progression of premalignant cervical lesions for cancer. In previous years it has been suggested that the adaptive immune response triggered by the differentiation of naïve helper T cells in Th17 cells may serve an important role in disease development. It has been hypothesized that Th17 cells may be involved in the promotion of UCC, as high levels of interleukin 17 (IL17) expression have been detected in the mucosa of the uterine cervix of patients affected by the disease. However, the role of Th17 cells in the tumor development and progression remains unclear. It is believed that the immune response of the Th17 type during persistent infection of the genital tract with HR-HPV triggers chronic inflammation with a long duration with the production of IL17 and other pro-inflammatory cytokines, creating a favorable environment for tumor development. These cytokines are produced by immune system cells in addition to tumor cells and appear to function by modulating the host immune system, resulting in an immunosuppressive response as opposed to inducing an effective protective immune response, thus contributing to the growth and progression of the tumor. In the present review, the latest advances are presented about the function of Th17 cells and the cytokines produced by them in the development and progression of UCC.

Th9 lymphocytes and functions of interleukin 9 with the focus on IBD pathology

The work presents the newest knowledge on a new phenotype of T helper lymphocytes (Th9) and on Interleukin 9 (IL-9). Processes leading to transformation of naïve T lymphocyte into Th9 lymphocytes are presented, including the role of IL-4 and TGFβ signaling. Involvement of transcription factor network in production of IL-9 is described. Other cells capable of expressing IL-9 and secreting IL-9 are portrayed. Diversity of IL-9 effects caused by activation of IL-9 receptors on various types of cells is presented. Principal effects of the activation of IL-9 receptor on T-cells seem to be antiapoptotic and stimulatory which leads to enhanced defense against parasitic infection and cancer development but, from the other side, it perpetuate chronic inflammation in autoimmune diseases and allergic processes. In the last years the role of IL-9 in autoimmune diseases such as rheumatic diseases and inflammatory bowel disease gained importance since the increased expression of this cytokine has been observed in animal models of intestinal inflammation and in groups of patients with ulcerative colitis. It was also noted that neutralization of IL-9 in animal models of ulcerative colitis leads to amelioration of inflammatory process, what could have significance in the treatment of this disease in humans in the future.

Role of Cytokine Combinations on CD4+ T Cell Differentiation, Partial Polarization, and Plasticity: Continuous Network Modeling Approach

Purpose: We put forward a theoretical and dynamical approach for the semi-quantitative analysis of CD4+ T cell differentiation, the process by which cells with different functions are derived from activated CD4+ T naïve lymphocytes in the presence of particular cytokine microenvironments. We explore the system-level mechanisms that underlie CD4+ T plasticity-the conversion of polarized cells to phenotypes different from those originally induced. Methods: In this paper, we extend a previous study based on a Boolean network to a continuous framework. The network includes transcription factors, signaling pathways, as well as autocrine and exogenous cytokines, with interaction rules derived using fuzzy logic. Results: This approach allows us to assess the effect of relative differences in the concentrations and combinations of exogenous and endogenous cytokines, as well as of the expression levels of diverse transcription factors. We found either abrupt or gradual differentiation patterns between observed phenotypes depending on critical concentrations of single or multiple environmental cytokines. Plastic changes induced by environmental cytokines were observed in conditions of partial phenotype polarization in the T helper 1 to T helper 2 transition. On the other hand, the T helper 17 to induced regulatory T-cells transition was highly dependent on cytokine concentrations, with TGFβ playing a prime role. Conclusion: The present approach is useful to further understand the system-level mechanisms underlying observed patterns of CD4+ T differentiation and response to changing immunological challenges.

Th9 Cells: Probable players in ulcerative colitis pathogenesis

T lymphocytes represent an important part of adaptive immune system undertaking different functions to regulate immune responses. CD4+ T cells are the most important activator cells in inflammatory conditions. Depending on the type of induced cells and inflamed sites, expression and activity of different subtypes of helper T cells are changed. Recent studies have confirmed the existence of a new subset of helper T lymphocytes called Th9. Naive T cells can differentiate into Th9 subtypes if they are exposed simultaneously by interleukin (IL) 4 and transforming growth factor β and also secondary activation of a complicated network of transcription factors such as interferon regulatory factor 4 (IRF4) and Smads which are essential for adequate induction of this phenotype. Th9 cells specifically produce interleukin 9 and their probable roles in promoting intestinal inflammation are being investigated in human subjects and experimental models of ulcerative colitis (UC). Recently, infiltration of Th9 cells, overexpression of IL-9, and certain genes associated with Th9 differentiation have been demonstrated in inflammatory microenvironment of UC. Intestinal oversecretion of IL-9 protein is likely to break down epithelial barriers and compromise tolerance to certain commensal microorganisms which leads to inflammation. Th9 pathogenicity has not yet been adequately explored in UC and they are far from being considered as inflammatory cells in this milieu, therefore precise understanding the role of these newly identified cells in particular their potential role in gut pathogenesis may enable us to develop novel therapeutic approaches for inflammatory bowel disease. So, this article tries to discuss the latest knowledge on the above-mentioned field.

Immunoporosis: Immunology of Osteoporosis-Role of T Cells

The role of immune system in various bone pathologies, such as osteoporosis, osteoarthritis, and rheumatoid arthritis is now well established. This had led to the emergence of a modern field of systems biology called as osteoimmunology, an integrated research between fields of immunology and bone biology under one umbrella. Osteoporosis is one of the most common inflammatory bone loss condition with more than 200 million individuals affected worldwide. T helper (Th) cells along with various other immune cells are major players involved in bone homeostasis. In the present review, we specifically discuss the role of various defined T lymphocyte subsets (Th cells comprising Th1, Th2, Th9, Th17, Th22, regulatory T cells, follicular helper T cells, natural killer T cells, γδ T cells, and CD8⁺ T cells) in the pathophysiology of osteoporosis. The study of the specific role of immune system in osteoporosis has now been proposed by our group as “immunoporosis: the immunology of osteoporosis” with special emphasis on the role of various subsets of T lymphocytes. The establishment of this new field had been need of the hour due to the emergence of novel roles of various T cell lymphocytes in accelerated bone loss observed during osteoporosis. Activated T cells either directly or indirectly through the secretion of various cytokines and factors modulate bone health and thereby regulate bone remodeling. Several studies have summarized the role of inflammation in pathogenesis of osteoporosis but very few reports had delineated the precise role of various T cell subsets in the pathobiology of osteoporosis. The present review thus for the first time clearly highlights and summarizes the role of various T lymphocytes in the development and pathophysiology of osteoporosis, giving birth to a new field of biology termed as “immunoporosis”. This novel field will thus provide an overview of the nexus between the cellular components of both bone and immune systems, responsible for the observed bone loss in osteoporosis. A molecular insight into the upcoming and novel field of immunoporosis would thus leads to development of innovative approaches for the prevention and treatment of osteoporosis.

Induction of specific T helper-9 cells to inhibit glioma cell growth

The effects of Staphylococcal enterotoxin B (SEB) on regulation of immune response have been recognized; whether SEB can enhance the effects of immunotherapy on glioma remains to be investigated. This study tests a hypothesis that administration with SEB enhances the effects of specific immunotherapy on glioma growth in mice. In this study, a glioma-bearing mouse model was developed by adoptive transfer with GL261 cells (a mouse glioma cell line). The mice were treated with the GL261 cell extracts (used as an Ag) with or without administration of SEB. We observed that treating glioma-bearing mice with the glioma Ag and SEB induced glioma-specific Th9 cells in both glioma tissue and the spleen. Treating CD4⁺ CD25⁻ T cells with SEB increased p300 phosphorylation, histone H3K4 acetylation at the interleukin (IL)-9 promoter locus, and increased the IL-9 transcriptional factor binding to the IL-9 promoter. Treating CD4⁺ CD25⁻ T cells with both SEB and glioma Ag induced glioma-specific Th9 cells. The glioma-specific Th9 cells induced glioma cell apoptosis in the culture. Treating the glioma-bearing mice with SEB and glioma Ag significantly inhibited the glioma growth. In conclusion, SEB plus glioma Ag immunotherapy inhibits the experimental glioma growth, which may be a novel therapeutic remedy for the treatment of glioma.

Guidance of super-enhancers in regulation of IL-9 induction and airway inflammation

Xiao et al. demonstrate that formation of super-enhancers at Il9 locus is critical for robust IL-9 expression and Th9 cell induction, and assembly of Il9 super-enhancers is driven by OX40-mediated chromatin acetylation.

Th9 cells are prominently featured in allergic lung inflammation, but the mechanism that regulates IL-9 induction in T helper cells remains poorly defined. Here we demonstrate that formation of super-enhancers (SEs) is critical in robust induction of IL-9 and that assembly of the Il9 SEs in Th cells requires OX40-triggered chromatin acetylation. Mechanistically, we found that OX40 costimulation induces RelB expression, which recruits the histone acetyltransferase p300 to the Il9 locus to catalyze H3K27 acetylation. This allows binding of the SE factor Brd4 to organize assembly of the SE complex, which in turn drives robust IL-9 expression and Th9 cell induction. Thus, Th9 cells are strongly induced upon OX40 stimulation, and disruption of SEs abolished Th9 cell induction in vitro and inhibited Th9 cell–mediated allergic airway inflammation in vivo. Together, our data suggest that formation of SEs is essential in IL-9 expression and Th9 cell induction. These findings may have important clinical implications.

Anti-inflammatory effects of interleukin-23 receptor cytokine-binding homology region rebalance T cell distribution in rodent collagen-induced arthritis

IL-23 is an important cytokine to regulate Th17 cell differentiation and promote the proliferation of inflammatory cells in Th17-mediated autoimmune diseases. The collagen-induced arthritis (CIA) in rat is a model of rheumatoid arthritis characterized by pronounced inflammatory auto-responses from B and T cells, especially Th17 cells in lesions. In the present study, we used rhIL23R-CHR to block the IL-23 signaling pathway to probe the importance of IL-23 in misbalancing the ratio of Th17/Th9/Treg cells in CIA rats. After treatments with rhIL23R-CHR, the CIA rats showed a significant decrease of secretions of IL-17 and IL-9, whereas FoxP3 was activated in the process, indicating that IL-23 can manipulate the balance of Th17/Th9/Treg cells. Similar to the animal model, IL-23 also possessed remarkable proinflammatory effects on human fibroblast-like synoviocyte cells (HFLS), showing synergetic outcomes with TNF-α. Together, IL-23 could act as a modulator to imbalance the ratio of Th17/Th9/Treg cells, and rhIL23R-CHR could serve as a potential therapeutic agent for RA patients.

Preferential susceptibility of Th9 and Th2 CD4+ T cells to X4-tropic HIV-1 infection

OBJECTIVE

The functional polarization of CD4 T cells determines their antimicrobial effector profile, but may also impact the susceptibility to infection with HIV-1. Here, we analyzed the susceptibility of CD4 T cells with different functional polarization to infection with X4 and R5-tropic HIV-1.

METHODS

CD4 T cells with a Th1, Th2, Th17, and Th9 polarization were subjected to in-vitro infection assays with X4, R5, or vesicular stomatitis virus-G protein-pseudotyped HIV-1. In addition, we sorted differentially polarized CD4 T-cell subsets from individuals treated with antiretroviral therapy and analyzed the tropism of viral env sequences.

RESULTS

Th9-polarized CD4 T cells and, to a lesser extent, Th2-polarized CD4 T cells expressed higher surface levels of CXCR4, and are more permissive to X4-tropic infection in vitro. In contrast, Th1 and Th17 CD4 T cells exhibited stronger surface expression of CCR5, and were more susceptible to infection with R5-tropic viruses. Correspondingly, the distribution of X4-tropic viral sequences in antiretroviral therapy-treated HIV-1-infected patients was biased toward Th9/Th2 cells, whereas R5-tropic sequences were more frequently observed in Th17 cells.

CONCLUSION

CD4 T-cell polarization is associated with a distinct susceptibility to X4 and R5-tropic HIV-1 infection.

The Immunogenicity of Branded and Biosimilar Infliximab in Rheumatoid Arthritis According to Th9-Related Responses

Our objective was to evaluate the immunogenicity of branded and biosimilar infliximab by detecting changes in T-helper-9 (Th9) percentages induced by an in vitro stimulation test.

METHODS

Peripheral blood mononuclear cells collected from 55 consecutive rheumatoid arthritis (RA) outpatients (15 drug free, 20 successfully treated with branded infliximab, 20 branded infliximab inadequate responders) and 10 healthy controls were cultured, with or without 50 μg/mL of infliximab originator (Remicade^®) or 50 μg/mL of infliximab biosimilar (Remsima^®) for 18 h. Th9 lymphocytes were identified by means of flow cytometry as PU.1 and IRF4-expressing, IL-9-secreting CD4⁺ T cells. Furthermore, the markers CCR7 and CD45RA were used to distinguish naïve from memory IL-9 producer cells.

RESULTS

Under unstimulated conditions, the drug-free RA patients had the highest percentages of Th9 lymphocytes. Following stimulation with branded infliximab, the percentages of PU.1 and IRF4-expressing Th9 cells, CCR7⁺, CD45RA^- (central memory) and CCR7^-, CD45RA^- (effector memory) cells significantly increased in the group of inadequate responders, but no significant variation was observed after exposure to the biosimilar of infliximab.

CONCLUSIONS

Th9 cells seem to be involved in the immune response to the epitopes of branded, but not biosimilar, infliximab, and this may depend on the recall and stimulation of both central and effector memory cells.

mTORC2 controls Th9 polarization and allergic airway inflammation

BACKGROUND

T helper type 9 (Th9) cells, a subpopulation of CD4⁺ T cells, play a critical role in the pathogenesis of allergic airway inflammation. However, it remains unknown whether mTORC2 regulates Th9 differentiation or function during allergic inflammation.

METHODS

T-cell-specific Rictor-deficient mice, a mouse model of allergic airway inflammation induced by ovalbumin (OVA) sensitization and a mouse model of adoptive transfer of induced Th9 cells, were used to address the roles of mTORC2 in the pathogenesis of allergic airway inflammation. The in vitro Th9 induction, multiple colors flow cytometry, real-time PCR, and Western blots were used to investigate the molecular effects of mTORC2 in Th9 induction.

RESULTS

The differentiation of naïve CD4⁺ T cells into Th9 cells was significantly diminished in the absence of Rictor, the core component of mTORC2. Using a mouse model of allergic airway inflammation induced by OVA sensitization, T-cell-specific Rictor-deficient mice show much less severe allergic airway inflammation characterized by decreased pathological alterations and fibrosis of the lungs, which was accompanied with reduced Th9 differentiation and infiltration. Importantly, the isolated Rictor-deficient Th9 cells mediate less severe allergic pathogenesis upon adoptive transfer. Rictor deficiency impairs Th9 cell differentiation by reducing IRF4 expression rather than affecting Foxo1/Foxo3a transcriptional activity, which is likely due to decreased Akt and/or STAT6 activation.

CONCLUSIONS

These findings uncover a novel role of mTORC2 in Th9 cell differentiation and may have important implications for therapeutic intervention of allergic diseases.

MicroRNA mediated regulation of immunity against gram-negative bacteria

Evidence over the last couple decades has comprehensively established that short, highly conserved, non-coding RNA species called microRNA (miRNA) exhibit the ability to regulate expression and function of host genes at the messenger RNA (mRNA) level. MicroRNAs play key regulatory roles in immune cell development, differentiation, and protective function. Intrinsic host immune response to invading pathogens rely on intricate orchestrated events in the development of innate and adaptive arms of immunity. We discuss the involvement of miRNAs in regulating these processes against gram negative pathogens in this review.

Phosphatase wild-type p53-induced phosphatase 1 controls the development of TH9 cells and allergic airway inflammation

BACKGROUND

Allergic asthma is one of the most common diseases worldwide, resulting in a burden of diseases. No available therapeutic regimens can cure asthma thus far.

OBJECTIVE

We sought to identify new molecular targets for T_H9 cell-mediated allergic airway inflammation.

METHODS

Wild-type p53-induced phosphatase 1 (Wip1) gene knockout mice, Wip1 inhibitor-treated mice, and ovalbumin-induced allergic airway inflammation mouse models were used to characterize the roles of Wip1 in allergic airway inflammation. The induction of T_H cell subsets in vitro, real-time PCR, immunoblots, luciferase assays, and chromatin immunoprecipitation assays were used to determine the regulatory pathways of Wip1 in T_H9 differentiation.

RESULTS

Here we demonstrate that Wip1-deficient mice are less prone to allergic airway inflammation, as indicated by the decreased pathologic alterations in lungs. Short-term treatment with a Wip1-specific inhibitor significantly ameliorates allergic inflammation progression. Intriguingly, Wip1 selectively impaired T_H9 but not T_H1, T_H2, and T_H17 cell differentiation. Biochemical assays show that Wip1 deficiency increases c-Jun/c-Fos activity in a c-Jun N-terminal kinase-dependent manner and that c-Jun/c-Fos directly binds to Il9 promoter and inhibits Il9 transcription.

CONCLUSION

Wip1 controls T_H9 cell development through regulating c-Jun/c-Fos activity on the Il9 promoter and is important for the pathogenesis of allergic airway inflammation. These findings shed light on the previously unrecognized roles of Wip1 in T_H9 cell differentiation. The inhibitory effects of a Wip1 inhibitor on the pathogenesis of allergic airway inflammation can have important implications for clinical application of Wip1 inhibitors in allergy therapies.

Detection of IL-9 producing T cells in the PBMCs of allergic asthmatic patients

BACKGROUND

Interleukin-9 (IL-9) was reported as an active participant in the pathogenesis of allergic asthma. This study aimed to investigate the major source ofIL-9 and its effect on interferon γ (IFN-γ) and immunoglobulin (Ig) secretion by B cells.

METHODS

We isolated peripheral blood mononuclear cells from children with allergic asthma and healthy children. IL-9, IL-4 and IFN-γ expression were detected by ELISA, ELISpot and Flowcytometry. Expression of transcription factor PU.1 was measured by Western Blot. We evaluated the effect of IL-9 on B cell activation and Ig production.

RESULTS

Results showed that compared with healthy children, levels of IL-9, IL-4 and PU.1 were elevated and levels of IFN-γ were lower in children with allergic asthma. IL-9-expressing CD4⁺ T cells did not co-express IL-4. Exogenous IL-9 inhibited IFN-γ production in a dose-dependent manner. Antigen-specific Th9 cells existed in children with house dust mite allergic asthma. IL-9 up-regulated expression of CD69 and CD25 on B cells and combination of IL-9 and IL-4 enhanced IgE production.

CONCLUSIONS

In conclusion, our results showed that Th9 cells may be the major source of IL-9 in children with allergic asthma. In these patients, IL-9 impairs IFN-γ production and synergistically promotes IL-4-induced IgE secretion.

Interleukin-9 Overexpression and Th9 Polarization Characterize the Inflamed Gut, the Synovial Tissue, and the Peripheral Blood of Patients With Psoriatic Arthritis

OBJECTIVE

To investigate the expression and tissue distribution of Th9-related cytokines in patients with psoriatic arthritis (PsA).

METHODS

Quantitative gene expression analysis of Th1, Th17, and Th9 cytokines was performed in intestinal biopsy samples obtained from patients with PsA, HLA-B27-positive patients with ankylosing spondylitis (AS), patients with Crohn's disease (CD), and healthy controls. Expression and tissue distribution of interleukin-23 (IL-23), IL-17, IL-22, IL-9, and IL-9 receptor (IL-9R) were evaluated by immunohistochemistry and confocal microscopy. Flow cytometry was used to study the frequency of Th9 cells among peripheral blood, lamina propria, and synovial fluid mononuclear cells. The functional relevance of IL-9R expression on epithelial cells was assessed in functional in vitro studies. Th9 cells in synovial tissue from patients with PsA were also studied.

RESULTS

Subclinical gut inflammation in PsA patients was characterized by a clear Th17 and Th22, but not Th1, polarized immune response. Unlike AS and CD, a strong and significant up-regulation of IL-9 was observed in PsA gut, especially among infiltrating mononuclear cells, high endothelial venules, and Paneth cells. IL-9-positive mononuclear cells were demonstrated to be in large part Th9 cells. IL-9 overexpression was accompanied by significant Paneth cell hyperplasia. Paneth cells strongly overexpressed IL-9R, and stimulation of epithelial cells, isolated from PsA patients, with IL-9 resulted in overexpression of α-defensin 5 and IL-23p19. Peripheral and synovial expansion of α4β7+ Th9 cells was also observed in patients with PsA. Increased expression of IL-9 and IL-9R was also found in synovial tissue.

CONCLUSION

Strong IL-9/Th9 polarization seems to be the predominant immunologic signature in patients in PsA.

Decreased frequency of circulating Th9 cells in patients with chronic hepatitis B infection

BACKGROUND

Chronic hepatitis B (CHB) is one of the major infectious diseases in which CD4+ T helper (Th) cells play a crucial role. Th9 cells are a distinct subset of CD4+ Th cells with important physiological functions.

OBJECTIVE

The study aimed to assess the potential involvement of Th9 cells in the inadequate immune response leading to chronic HBV infection.

PATIENTS AND METHODS

Peripheral blood samples were collected from 22 CHB patients and 16 healthy controls (HC). The frequencies of circulating Th9, Tc9, Th1, and Tc1 cells were determined by flow cytometry. Serum levels of IL-9 and IL-10 were analyzed by ELISA. Serum biochemical indices of liver function were measured using an automated analyzers. Serum HBV DNA loads were analyzed by real-time PCR. The potential association of the frequency of Th9, Tc9, Th1 or Tc1 cells with clinical parameters was assessed.

RESULTS

The frequency of circulating Th9 cells was significantly lower in CHB patients than those in HC. However, no significant differences in the frequency of Tc9, Th1 or Tc1 cells were observed between the two groups. The percentages of Th9 cells, but not Tc9 cells, were negatively correlated with HBV DNA loads, whereas the percentages of Tc1 cells were positively correlated with viral loads in CHB patients. Moreover, there was a positive correlation between serum levels of IL-9 and IL-10 and HBV DNA loads in patients with chronic HBV infection.

CONCLUSION

The depletion of Th9 cells is associated with the development of chronic HBV infection.

The ST2/IL-33 Axis in Immune Cells during Inflammatory Diseases

Il1rl1 (also known as ST2) is a member of the IL-1 superfamily, and its only known ligand is IL-33. ST2 exists in two forms as splice variants: a soluble form (sST2), which acts as a decoy receptor, sequesters free IL-33, and does not signal, and a membrane-bound form (ST2), which activates the MyD88/NF-κB signaling pathway to enhance mast cell, Th2, regulatory T cell (Treg), and innate lymphoid cell type 2 functions. sST2 levels are increased in patients with active inflammatory bowel disease, acute cardiac and small bowel transplant allograft rejection, colon and gastric cancers, gut mucosal damage during viral infection, pulmonary disease, heart disease, and graft-versus-host disease. Recently, sST2 has been shown to be secreted by intestinal pro-inflammatory T cells during gut inflammation; on the contrary, protective ST2-expressing Tregs are decreased, implicating that ST2/IL-33 signaling may play an important role in intestinal disease. This review will focus on what is known on its signaling during various inflammatory disease states and highlight potential avenues to intervene in ST2/IL-33 signaling as treatment options.

Overexpression and varied clinical significance of Th9 versus Th17 cells in distinct subtypes of oral lichen planus

OBJECTIVE

Oral lichen planus (OLP) presents with large numbers of T lymphocytes accumulating beneath the epithelium of the oral mucosa; however, its aetiology remains obscure. A potential role for an emerging novel T cell subset, Th9, in OLP has recently been suggested but remains to be clarified. The current aim was to investigate the expression and potential clinical significance of Th9 cells in distinct subtypes of OLP.

MATERIALS AND METHODS

Peripheral blood samples were collected from 41 OLP patients and 18 healthy controls (HCs). Flow cytometric analysis was used to detect the CD4+ T helper subset Th9 (IL-9⁺IL-17^-CD4⁺ Th cells) and Th17 (IL-9^-IL-17⁺CD4⁺ Th cells) expression levels.

RESULTS

Flow cytometry results showed significantly elevated levels of Th9 cells in reticular and erosive OLP compared to HCs. Th9 expression in erosive OLP was less than in reticular OLP, indicating that Th9 but not Th17 cells may play a predominant role in reticular disease. However, in erosive OLP patients, we found much higher levels of Th17 cells compared to reticular OLP patients and HCs, indicating that Th17 dominates in erosive OLP. Statistical analysis showed positive correlations of Th9 cells and Th17 cells in patients with reticular or erosive OLP but none in HCs.

CONCLUSIONS

Th9 and Th17 cells may take the predominant roles in reticular and erosive OLP respectively, and their numbers were positively correlated in reticular and erosive OLP patients. Elevated circulating Th9 cells may help maintain immune balance in OLP immunopathogenesis, which requires further investigation.

Melatonin signaling in T cells: Functions and applications

Melatonin affects a variety of physiological processes including circadian rhythms, cellular redox status, and immune function. Importantly, melatonin significantly influences T-cell-mediated immune responses, which are crucial to protect mammals against cancers and infections, but are associated with pathogenesis of many autoimmune diseases. This review focuses on our current understanding of the significance of melatonin in T-cell biology and the beneficial effects of melatonin in T-cell response-based diseases. In addition to expressing both membrane and nuclear receptors for melatonin, T cells have the four enzymes required for the synthesis of melatonin and produce high levels of melatonin. Meanwhile, melatonin is highly effective in modulating T-cell activation and differentiation, especially for Th17 and Treg cells, and also memory T cells. Mechanistically, the influence of melatonin in T-cell biology is associated with membrane and nuclear receptors as well as receptor-independent pathways, for example, via calcineurin. Several cell signaling pathways, including ERK1/2-C/EBPα, are involved in the regulatory roles of melatonin in T-cell biology. Through modulation in T-cell responses, melatonin exerts beneficial effects in various inflammatory diseases, such as type 1 diabetes, systemic lupus erythematosus, and multiple sclerosis. These findings highlight the importance of melatonin signaling in T-cell fate determination, and T cell-based immune pathologies.

T Cells in Osteoarthritis: Alterations and Beyond

Although osteoarthritis (OA) has been traditionally regarded as a non-inflammatory disease, reports increasingly suggest that it is inflammatory, at least in certain patients. OA patients often exhibit inflammatory infiltration of synovial membranes by macrophages, T cells, mast cells, B cells, plasma cells, natural killer cells, dendritic cells, granulocytes, etc. Although previous reviews have summarized the knowledge of inflammation in the pathogenesis of OA, as far as we know, no report review our current understanding about T cells, especially, each T cell subtype, in the biology of OA. This review highlights the current understanding of the role of T cells in the pathogenesis of OA, with attention to Th1 cells, Th2 cells, Th9 cells, Th17 cells, Th22 cells, regulatory T cells, follicular helper T cells, cytotoxic T cells, T memory cells, and even unconventional T cells (e.g., γδ T cells and cluster of differentiation 1 restricted T cells). The findings highlight the importance of T cells to the development and progression of OA and suggest new therapeutic approaches for OA patients based on the manipulation of T-cell responses.

Amino-acid transporters in T-cell activation and differentiation

T-cell-mediated immune responses aim to protect mammals against cancers and infections, and are also involved in the pathogenesis of various inflammatory or autoimmune diseases. Cellular uptake and the utilization of nutrients is closely related to the T-cell fate decision and function. Research in this area has yielded surprising findings in the importance of amino-acid transporters for T-cell development, homeostasis, activation, differentiation and memory. In this review, we present current information on amino-acid transporters, such as LAT1 (l-leucine transporter), ASCT2 (l-glutamine transporter) and GAT-1 (γ-aminobutyric acid transporter-1), which are critically important for mediating peripheral naive T-cell homeostasis, activation and differentiation, especially for Th1 and Th17 cells, and even memory T cells. Mechanically, the influence of amino-acid transporters on T-cell fate decision may largely depend on the mechanistic target of rapamycin complex 1 (mTORC1) signaling. These discoveries remarkably demonstrate the role of amino-acid transporters in T-cell fate determination, and strongly indicate that manipulation of the amino-acid transporter-mTORC1 axis could ameliorate many inflammatory or autoimmune diseases associated with T-cell-based immune responses.

Cells of the innate and adaptive immunity and their interactions in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a group of chronic inflammatory conditions of the gastrointestinal tract that includes two major phenotypes, Crohn's disease and ulcerative colitis that are characterized by different clinical features and different course of the immune response. The exact aetiology of IBD still remains unknown, although it is thought that the diseases result from an excessive immune response directed against microbial or environmentally derived antigens which can be triggered by the disruption of the intestinal epithelial barrier integrity. In this review we present immune mechanisms and interactions between cells of the immune system and tissue environment that contribute to the development and progression of IBD in humans. Since dysregulation of the intestinal immune response is a hallmark of chronic inflammatory conditions, we characterize cells of the innate and adaptive immunity involved in the pathogenesis of IBD and their cross-talks. We describe various subclasses of recently discovered innate lymphoid cells, as well as dendritic cells, macrophages and T cells, including Th17, Th22 and T regulatory cells, present in the intestinal lamina propria and cytokine-mediated regulation of the immune response in IBD, highlighting the role of IL-22 and IL-17A/IL-23 axis. Insights into novel therapeutic modalities targeting certain elements of the immune pathways important for the pathogenesis of IBD have been also shortly presented.

Negative Regulation of Type 2 Immunity

Type 2 immunity encompasses the mechanisms through which the immune system responds to helminths and an array of environmental substances such as allergens. In the developing world, billions of individuals are chronically infected with endemic parasitic helminths. In comparison, in the industrialized world, millions of individuals suffer from dysregulated type 2 immunity, referred to clinically as atopic diseases including asthma, allergic rhinitis, and atopic dermatitis. Thus, type 2 immunity must be carefully regulated to mount protective host responses yet avoid inappropriate activation and immunopathology. In this review, we describe the key players and connections at play in type 2 responses and focus on the emerging mechanisms involved in the negative regulation of type 2 immunity.

Anti-Interleukin-9 Antibody Increases the Effect of Allergen-Specific Immunotherapy in Murine Allergic Rhinitis

Purpose

Interleukin (IL)-9 induces allergic responses; however, the roles of anti-IL-9 antibody in the induction of tolerance remain unclear. This study investigated the effects of anti-IL-9 antibody on oral tolerance (OT) in a mouse model of allergic rhinitis (AR).

Methods

BALB/c mice were divided into 4 groups: the control, AR, OT, and OT with anti-IL-9 antibody (OT+IL9AB) groups. Ovalbumin (OVA) was used for sensitization and challenge. Mice in the OT and OT+IL9AB groups were fed OVA for immunotherapy. During immunotherapy, OT+IL9AB mice were injected with anti-IL-9 antibody. Allergic symptoms, tissue eosinophil counts, and serum OVA-specific immunoglobulin E (IgE) were measured. The mRNA expressions of cytokines and transcription factors of T cells of nasal mucosa were determined by real-time polymerase chain reaction (PCR). The protein levels of GATA3, ROR-γt, and Foxp3 in nasal mucosa were determined by Western blot. CD4⁺CD25⁺Foxp3⁺ T cells in the spleen were analyzed by flow cytometry.

Results

Administration of anti-IL-9 antibody decreased allergic symptoms, OVA-specific IgE levels, and eosinophil counts. In addition, it inhibited T-helper (Th) 2 responses, but had no effect on Th1 responses. Protein levels of ROR-γt and mRNA levels of PU.1 and ROR-γt were reduced by anti-IL-9 antibody. Anti-IL-9 antibody increased Foxp3 and IL-10 mRNA expression, Foxp3 protein, and induction of CD4⁺CD25⁺Foxp3⁺ T cells.

Conclusions

Anti-IL-9 antibody decreased allergic inflammation through suppression of Th2 and Th17 cells. Anti-IL-9 antibody enhanced the tolerogenic effects of regulatory T cells. These results suggest that anti-IL-9 antibody might represent a potential therapeutic agent for allergen immunotherapy in patients with uncontrolled allergic airway disease.

Characterization of Th9 Cells in the Development of EAE and IBD

Encephalitogenic and colitogenic effector T cells have been implicated in the induction of experimental autoimmune encephalomyelitis (EAE) and inflammatory bowel disease (IBD), respectively. Effector functions of Th1 and Th17 cells have been well characterized and described for the induction and development of EAE and IBD; however, the recently identified Th9 cells have also been suggested to play an important role in these autoimmune pathologies. Th9 cells, primarily characterized by their high level of production of IL-9, are not only essential in controlling extracellular pathogens but also contribute to the development of autoimmunity and allergic inflammation. Furthermore, it was also demonstrated that IL-9 promotes Th17 cell-mediated tissue pathology in EAE and it compromises the barrier functions of the gut in IBD. In vivo adoptive transfer of in vitro differentiated Th9 cells induces the development of autoimmune tissue inflammation in EAE and IBD. Here we describe methods for in vitro differentiation of naïve murine CD4+ T cells to generate IL-9-producing Th9 cells and follow their effector functions in EAE and IBD murine models.

Circulating T helper 9 cells and increased serum interleukin-9 levels in patients with knee osteoarthritis

The purpose of this study was to examine the roles of T helper 9 (Th9) cells and the serum interleukin (IL)-9 level in the pathogenesis of osteoarthritis (OA). The numbers of IL-9(+) CD4(+) CD8(-) T cells, interferon (IFN)-γ+ CD4(+) CD8(-) T cells, IL-4(+) CD4(+) CD8(-) T cells, and IL-17A(+) CD4(+) CD8(-) T cells in 25 OA patients and 13 healthy controls (HC) were examined by flow cytometry. The serum concentrations of IL-9, IL-4, IL-17A, and IFN-γ were also determined. The numbers of CD4(+) CD45RO(+) T cells, Th9 cells, Th1 cells, and Th17 cells in OA patients were significantly higher than those in HCs. Furthermore, serum IL-9, IL-17A, and IFN-γ levels in OA patients were higher than those in HCs. The number of Th9 cells was positively correlated with the number of Th17 cells in OA patients. Furthermore, greater numbers of Th9 cells were positively associated with elevated C-reactive protein, and both Th9 cells and IL-9 levels were positively correlated with the Western Ontario and McMaster Universities Osteoarthritis index in OA patients. Th9 cell numbers and IL-9 levels are correlated with OA patient symptoms and joint functionality and may be a marker of disease activity.

Th9 cytokines response and its possible implications in the immunopathogenesis of leprosy

AIMS

Leprosy is an infectious-contagious disease whose clinical evolution depends on the interaction of the infectious agent with the immune response of the host, leading to a clinical spectrum that ranges from lepromatous leprosy (susceptibility, LL) to tuberculoid leprosy (resistance, TT). The immune response profile will depend on the pattern of cytokine production and on the activity of macrophages during infection. Classically, the clinical evolution of leprosy has been associated with Th1/Th2 cytokine profiles, but the role of new cytokine profiles such as T helper 9 (Th9) remains to be elucidated.

METHODS

To evaluate the tissue expression profile of these cytokines, a cross-sectional study was conducted using a sample of 30 leprosy skin lesion biopsies obtained from patients with leprosy, 16 TT and 14 lepromatous LL.

RESULTS

Immunohistochemical analysis revealed a significant difference in interleukin (IL)-9, IL-4 transforming growth factor (TGF)-β and IL-10 levels between the two groups. IL-9 was more expressed in TT lesions compared with LL lesions. Higher expression of IL-4, IL-10 and TGF-β was observed in LL compared with TT. IL-4, IL-10 and TGF-β tended to be negatively correlated with the expression of IL-9, indicating a possible antagonistic activity in tissue.

CONCLUSIONS

The results suggest that Th9 lymphocytes may be involved in the response to Mycobacterium leprae, positively or negatively regulating microbicidal activity of the local immune system in the disease.

TH9 cells in skin disorders

Interleukin 9 secreting T_H9 cells have been proposed as the latest addition to the family of T helper cell subsets. While a growing body of evidence from animal models points to important roles for these cells in allergic inflammation of the lung, autoinflammation of the gastrointestinal tract, and tumor immunity, their role in skin immunity and skin immunopathology remains poorly defined. Interestingly, studies of T helper cells from healthy humans suggest that T_H9 cells are predominantly skin-homing and skin-resident and that they are involved in protection against extracellular pathogens. Thus, T_H9 cells have entered the stage as potential mediators of cutaneous pathology. However, under which conditions and by which mechanisms these cells contribute to skin immunity and disease still has to be investigated. Here, we review our current understanding of T_H9 cells as skin-tropic T helper cells and their involvement in skin pathology. Further, we discuss open questions with regard to the intricate nature of interleukin 9 producing T helper cells.

Friend or Foe? The Ambiguous Role of Innate Lymphoid Cells in Cancer Development

The development of immunotherapies represents a major advance towards the effective eradication of malignant tumors. So far, therapeutic approaches have largely focused on T lymphocytes, but the innate arm of the immune system might be similarly important. Innate lymphoid cells (ILCs) are rapidly-responding cells that are functionally analogous to diverse T cell subsets. In recent years these cells have attracted enormous attention owing to their pleiotropic effects in early host defense to infection and organ pathologies. ILCs might also represent promising targets in the context of cancer therapy because they are an innate immune cell population endowed with potent immunomodulatory properties. In this review we discuss the impact of the three ILC subsets and the signature cytokines they release on cancer development and tumor growth.

Distinct interferon-gamma and interleukin-9 expression in cutaneous and oral lichen planus

BACKGROUND

Cutaneous (CLP) and oral lichen planus (OLP) as the main subtypes of lichen planus (LP) present with different clinical manifestation and disease course, although their histopathologic features such as the band-like lymphocyte infiltrate and keratinocyte apoptosis are similar. So far, the underlying cellular and molecular mechanisms remain poorly understood.

OBJECTIVE

The aim of this study was to characterize and compare the in situ cellular infiltrates, cytokine expression profiles and apoptosis markers in CLP and OLP.

METHODS

Using immunofluorescence staining and laser scanning microscopy, we evaluated the cellular infiltrate (CD1a, CD3, CD4, CD8, CD21, CD57, CD123), cytokine expression (interleukin (IL)-1, IL-6, IL-9, IL-10, IL-17, IL-22, IL-23, tumour necrosis factor-α, transforming growth factor-β, interferon (IFN)-γ), and apoptosis markers (Fas, Fas ligand, cleaved caspase-3, TUNEL) of 21 anonymized biopsy specimens of LP (11 CLP, 10 OLP).

RESULTS

Among infiltrating cells mainly T cells and natural killer (NK) cells as well as plasmacytoid dendritic cells (DC) were observed. A predominance of CD8+ T cells was noted in OLP. In both CLP and OLP, T helper (Th)1, Th9, Th17, and Th22-type cytokines were expressed. The expression of IL-9, IFN-γ and IL-22 was higher in CLP compared to that of OLP (P = 0.0165; P = 0.0016; P = 0.052 respectively). Expression of Fas and Fas ligand as well as cleaved caspase-3-positive cells was observed in the epithelium of all LP samples.

CONCLUSIONS

The cell and cytokine patterns of CLP and OLP were partially distinct and generally resembled those reported for autoimmune diseases. The presence of CD8+ and NK cells as well as Fas/Fas ligand expression suggested that various pathways involved in keratinocyte apoptosis are relevant for LP. These results might help to establish targeted therapies for LP.

IL-23 plasma level is strongly associated with CMV status and reactivation of CMV in renal transplant recipients

Background

Cytomegalovirus seropositivity is an independent risk factor for atherosclerosis in patients with ESRD. Donor CMV seropositivity is associated with higher graft loss. Dendritic cells, macrophages and Th17 lymphocytes are defined as producers of IL-23. IL-23 is thought to be involved in the promotion of Th17 cell polarization. Latent CMV-induced Th17 might be involved in the pathogenesis of CMV infection in patients with ESRD. We aimed to evaluate associations of Th17-dependent cytokines with ESRD, CMV status and post-transplant outcome in kidney transplantation.

Results

IL-21 plasma levels were similar in patients and healthy controls (p = 0.47), whereas IL-9 (p = 0.02) and IL-23 (p < 0.0001) levels were significantly higher in ESRD patients. CMV-seronegative (p = 0.002) and –seropositive (p < 0.001) patients had significantly higher IL-23 plasma levels than controls. CMV-seropositive patients showed excessively higher IL-23 (p < 0.001) plasma levels than CMV-seronegative patients. Patients with post-transplant CMV reactivation had higher IL-23 plasma levels than patients without CMV reactivation (p = 0.025).

Conclusions

Our results indicate that latent CMV induces IL-23. IL-23 might be an inflammatory mediator of latent CMV infection in patients with ESRD and predisposes patients for post-transplant CMV reactivation.