Systemic Th17 response in the presence of periodontal inflammation

Abstract The relationship between periodontitis and the pathogenesis of other inflammatory diseases, such as diabetes, rheumatoid arthritis and obesity has been an important topic of study in recent decades. The Th17 pathway plays a significant role in how local inflammation can influence systemic inflammation in the absence of systemic pathology. Objective: To determine Th17 biased-cells in systemically healthy patients in the presence of generalized chronic periodontitis. Methodology: A total of 28 patients were recruited without systemic inflammatory pathology, which was determined by clinical history, the Health Assessment Questionnaire (HAQ) and rheumatoid factor detection. Of these patients, 13 were diagnosed as healthy/gingivitis (H/G) and 15 as generalized chronic periodontitis (GCP). Th17 (CD4+CD161+) cells and Th17IL23R+ (CD4+CD161+IL-23R+) cells were quantified by flow cytometry, based on the total cells and on the lymphocyte region, termed the "enriched population" (50,000 events for each). Results: The percentages of Th17 cells of the H/G and periodontitis groups were similar on total cells and enriched population (19 vs 21.8; p=4.134 and 19.6 vs 21.8; p=0.55). However, Th17IL23R+ cells differ significantly between periodontally healthy patients and generalized chronic periodontitis patients in both total cell (0.22% vs 0.65%; p=0.0004) and enriched populations (0.2% vs 0.75%; p=0.0266). Conclusions: GCP patients (otherwise systemically healthy) were characterized by increased Th17-proinflammatory cell phenotype positive for the IL-23 receptor in peripheral blood. The proportion of Th17 cells that are negative for the IL-23 receptor in the peripheral blood of systemically healthy patients seemed to be unaffected by the presence or absence of chronic periodontitis.

Critical role of metabotropic glutamate receptor 4 in bone marrow-derived dendritic cells in the Th17 cell differentiation and the melanogenesis of B16 cells

Vitiligo is an acquired pigmentary disorder resulting from selective destruction of melanocytes. Emerging studies have suggested that T helper cell 17 (Th17) is potentially implicated in vitiligo development and progression. It was recently discovered that metabotropic glutamate receptor 4 (mGluR4) can modulate Th17-mediated adaptive immunity. However, the influence of mGluR4 on melanogenesis of melanocytes has yet to be elucidated. In the present study, we primarily cultured mouse bone marrow-derived dendritic cells (BMDC) and then knocked down and over-expressed mGluR4 using transfection. Transduced BMDC were co-cultured with CD4+ T cells and the expression of Th17-related cytokines were measured. The morphology and melanogenesis of B16 cells were observed after being treated with co-culture medium of CD4+ T cells and transduced BMDC. We found that mGluR4 knockdown did not affect the co-stimulatory CD80 and CD86 upregulation after lipopolysaccharide stimulation but did increase the expression of Th17-related cytokines, and further down-regulated the expression of microphthalmia-associated transcription factor (MITF) and the downstream genes, decreased melanin production, and destroyed the morphology of B16 cells. Conversely, over-expression of mGluR4 reduced the expression of CD80 and CD86, suppressed the production of Th17-related cytokines, increased the expression of MITF, and did not destroy the morphology of B16 cells. Our study confirmed that mGluR4 modulated the Th17 cell polarization and resulted in the alteration of melanogenesis and morphology of B16 cells. Collectively, these findings suggest mGluR4 might be a potent target involved in the immune pathogenesis of vitiligo.

Evaluation of the Th17 pathway in psoriasis and geographic tongue

Abstract Background: Psoriasis is a skin-articular disease with unclear etiopathogenesis. It has been suggested that the disease is immune-mediated by T-lymphocytes, predominantly Th17 cells. Similar to psoriasis, geographic tongue is an inflammatory disease with participation of Th17 cells and direct correlation with psoriasis. Objective: To investigate and compare the inflammatory responses and the Th17 pathway in psoriasis and geographic tongue. Methods: This was a cross-sectional study with 46 participants that were categorized into three groups: (A) patients with psoriasis vulgaris; (B) patients with geographic tongue and psoriasis; (C) patients with geographic tongue without psoriasis. All patients underwent physical examination, and a skin and oral biopsy for histopathological examination and immunohistochemical analysis with anti-IL6, anti-IL17, and anti-IL23 antibodies. Results: Histological analysis of all lesions showed mononuclear inflammatory infiltrate. However, moderate intensity was prevalent for the patients with geographic tongue and psoriasis and geographic tongue groups. Immunopositivity for the antibodies anti-IL6, anti-IL17, and anti-IL23 revealed cytoplasmic staining, mainly basal and parabasal, in both psoriasis and geographic tongue. Regarding IL-6, in patients with geographic tongue and psoriasis cases the staining was stronger than in patients with geographic tongue without psoriasis cases. IL-17 evidenced more pronounced and extensive staining when compared to the other analyzed interleukins. IL-23 presented similar immunopositivity for both geographic tongue and psoriasis, demonstrating that the neutrophils recruited into the epithelium were stained. Study limitation: This study was limited by the number of cases. Conclusion: The inflammatory process and immunostaining of IL-6, IL-17, and IL-23 were similar in geographic tongue and psoriasis, suggesting the existence of a type of geographic tongue that represents an oral manifestation of psoriasis.

Cytokines and chemokines associated with Treg/Th17 response in chronic inflammatory periapical disease

Abstract Cytokines and chemokines have a fundamental role in the maintenance of inflammation and bone response, which culminate in the development of chronic periapical lesions. Regulatory (Treg) and Th17 cytokines play a key role in regulating the immune response involved in this process. The aim of this study was to investigate the role of Treg and Th17 cells in chronic inflammatory periapical disease, by comparing the expression of the immunoregulatory mediators TGF-β, IL-10, CCL4, and the proinflammatory IL-17 and CCL20 in the periapical tissue of teeth with pulp necrosis, with and without associated chronic lesions. Eighty-six periapical tissue samples were obtained from human teeth. The samples were divided into three groups: pulp necrosis with a periapical lesion (n=26); pulp necrosis without a periapical lesion (n=30), and control (n=30). All samples were submitted to histopathological analysis and cytokine and chemokine measurement through ELISA. Statistical analyses were done with Kruskal-Wallis and Mann-Whitney tests and Spearman correlation. The group with pulp necrosis and a periapical lesion showed a higher expression of CCL4 and TGF-β in comparison with pulp necrosis without a lesion. CCL20 was higher in the group with a periapical lesion when compared to the control. In all groups there was a weak positive correlation between IL-17/CCL20, IL-10/CCL4, and IL-17/TGF-β. Both types of cytokines, pro-inflammatory and immunoregulatory, occur simultaneously in periapical tissue. However, a rise in immunosuppressive cytokines and chemokines (CCL4 and TGF-β) in periapical lesions suggests a role of these cytokines in stable periapical disease.

Ultrasound inflammatory parameters and Treg/Th17 cell profiles in established rheumatoid arthritis

Abstract Background: Imbalance and disfuntion in regulatory T-cells (Tregs) and IL-17 producer lymphocytes (Th17) have been implicated in the pathogenesis of rheumatoid arthritis (RA). Gray scale synovial proliferation (GS), power Doppler signal (pD) and bone erosions seen on high resolution muskuloskeletal ultrasound (MSUS) are hallmarks of destructive articular disease. Objective: To evaluate the association of peripheral Tregs and Th17 with MSUS findings in RA. Methods: RA patients (1987 ACR criteria) treated with disease-modifying antirheumatic drugs (DMARDs) were included. Lymphocytes were isolated and immunophenotyped by flow cytometry to investigate regulatory FoxP3+ T cells and IL-17+ cells. MSUS (MyLab 60, Esaote, Genova, Italy, linear probe 6-18 MHz) was performed on hand joints, and a 10-joint US score was calculated for each patient. Results: Data on lymphocytes subsets were avaiable for 90 patients. The majority of patients were Caucasian women with a median disease duration of 6 years (interquartile range: 2-13 years). Mean DAS28 was 4.28 (SD ± 1.64) and mean HAQ score was 1.11 (SD ± 0.83). There was no significant correlation of 10-joint GS score (rS = 0.122, 95% CI: - 0.124 to 0.336, P = 0.254) and 10-joint pD score (rS = 0.056, 95% CI: - 0.180 to 0.273, P = 0.602) with the mean percentage of peripheral Treg cells. Also, 10-joint GS score (rS = 0.083, 95% CI: - 0.125 to 0.302, P = 0.438) and 10-joint pD score 10 (rS = - 0.060, 95% CI: - 0.271 to 0.150, P = 0.575); did not correlate to Th17 profile. No association of bone erosions on MSUS with Treg and Th17 profiles (P = 0.831 and P = 0.632, respectively) was observed. Conclusion: In this first study addressing MSUS features and lymphocytes subtypes in established RA, data did not support an association of circulating Tregs and Th17 lymphocytes with inflammatory and structural damage findings on MSUS.

The potential role of Th17 lymphocytes in patients with psoriasis

Abstract: Background: Psoriasis is a chronic inflammatory disorder, characterized by increased keratinocyte proliferation due to abnormal differentiation of basal keratinocytes. The etiology of the disease is unclear, and according to the survey results, it is hypothesized that a combination of genetic and environmental factors prompts an abnormal immune response in patients with psoriasis. CD4+ Th cells play a multifaceted role in both immune defense and pathogenesis of certain diseases such as psoriasis. Nonetheless, the exact contribution of different subpopulations of Th cells in psoriasis is still not clear. Objective: The aim of present study was to determine the mRNA expression level of RORC as potential inducer of Th17 cell differentiation and expression pattern of Th17-signature cytokines (IL-17A and IL-22). Methods: Twenty patients with psoriasis and twenty-one healthy subjects were included in the study. Peripheral blood mononuclear cells (PBMCs) were separated and expression of three genes were determined by quantitative real-time reverse transcriptase PCR (qRT-PCR). Plasma levels of IL-17 and IL-22 were also evaluated by ELISA. Results: RORC, IL-17A and IL-22 gene expression was significantly higher in patients with psoriasis compared with healthy controls (P<0.05). In addition, a marked increase in plasma IL-17A and IL-22 levels was observed in patient group compared to controls (P<0.001). Study limitations: small number of patients. Conclusion: These data suggest that Th17 response may contribute to the pathogenesis of psoriasis.

Imbalance of γδT17/γδTreg cells in the pathogenesis of allergic asthma induced by ovalbumin

We aimed to explore the imbalance between the T helper 17 γδT cells (γδT17) and the regulatory γδT cells (γδTreg) in asthmatic mice. Male Balb/c mice were randomly divided into the normal control group and the asthmatic model group. The asthmatic model group mice were intraperitoneally injected with the mixture of ovalbumin (OVA)/Al(OH)3 and then activated by exposure of the animals to OVA atomization. Airway hyperresponsiveness (AHR) was determined by a non-invasive lung function machine. Hematoxylin and eosin and Alcian blue-periodic acid Schiff staining were done for histopathological analysis. Interleukin (IL)-17 and IL-35 levels in bronchoalveolar lavage fluid were detected by ELISA. The percentage of IL-17+ γδT cells and Foxp3+ γδT cells in spleen cells suspension were detected and the transcription levels of RORγt and Foxp3 in the lung tissue were determined. Compared with the normal control, the severity of airway inflammation and AHR were higher in the asthmatic mice. Furthermore, mice in the asthmatic group displayed significant increases of IL-17+ γδT cells, expression of IL-17A, and RORγt, whereas control mice displayed marked decreases of Foxp3+ γδT cells, expression of IL-35, and transcription factor Foxp3. In addition, the mRNA expression of RORγt was positively correlated with the percentage of IL-17+γδT cells, and the mRNA level of Foxp3 was positively correlated with the percentage of Foxp3+ γδT cells. The imbalance of γδT17/γδTreg in the asthmatic mice may contribute to the pathogenesis of OVA-induced asthma.

Imbalance of Th17 and Treg in peripheral blood mononuclear cells of active tuberculosis patients

Abstract Objective: Maintaining a right balance between Th17 and Treg might be critical to the immunopathogenesis of active tuberculosis (TB). This study aimed to assess whether the Th17/Treg balance is altered in active TB patients. Methods: 250 study subjects (90 active TB patients, 80 latent TB subjects, and 80 healthy controls) were recruited for the study. The expression of Th17 and Treg in peripheral blood mononuclear cells (PBMCs) in the 250 subjects was investigated by flow cytometry. Plasma levels of cytokines IL-17 and IL-10, which are related to Th17 and Treg, respectively, were determined by ELISA. Results: The percentages of Th17 and Treg in PBMCs from active TB patients were significantly higher than those from latent TB or control groups (Th17: 4.31 ± 1.35% vs. 1.58 ± 0.71% or 1.15 ± 0.49%, p < 0.05; Treg: 11.44 ± 2.69% vs. 7.54 ± 1.56% or 4.10 ± 0.99%, p < 0.05). The expression of IL-17 and IL-10 was significantly increased in active TB patients in comparison to that in latent TB or control groups (IL-17: 16.85 ± 9.68 vs. 7.23 ± 5.19 or 8.21 ± 5.51 pg/mL, p < 0.05; IL-10: 28.70 ± 11.27 vs. 20.25 ± 8.57 or 13.94 ± 9.00 pg/mL, p < 0.05). Conclusions: Our study demonstrated an altered balance of Treg/Th17 in active TB patients, with higher percentages of Th17 and Treg in PBMCs. Further research on this imbalance may offer a new direction for TB treatment.

Tangeretin has anti-asthmatic effects via regulating PI3K and Notch signaling and modulating Th1/Th2/Th17 cytokine balance in neonatal asthmatic mice

Asthma is a chronic allergic disease characterized by airway inflammation, airway hyper-responsiveness (AHR), and mucus hypersecretion. T-lymphocytes are involved in the pathogenesis of asthma, mediating airway inflammatory reactions by secreting cytokines. The phosphoinositide 3-kinase (PI3K) and Notch signaling pathways are associated with T cell signaling, proliferation, and differentiation, and are important in the progression of asthma. Thus, compounds that can modulate T cell proliferation and function may be of clinical value. Here, we assessed the effects of tangeretin, a plant-derived flavonoid, in experimental asthma. BALB/c mice at postnatal day (P) 12 were challenged with ovalbumin (OVA). Separate groups of mice (n=18/group) were administered tangeretin at 25 or 50 mg/kg body weight by oral gavage. Dexamethasone was used as a positive control. Tangeretin treatment reduced inflammatory cell infiltration in bronchoalveolar lavage fluid (BALF) and also restored the normal histology of lung tissues. OVA-specific IgE levels in serum and BALF were reduced. AHR, as determined by airway resistance and lung compliance, was normalized. Flow cytometry analyses revealed a reduced Th17 cell population. Tangeretin reduced the levels of Th2 and Th17 cytokines and raised IFN-γ levels. PI3K signaling was inhibited. The expressions of the Notch 1 receptor and its ligands Jagged 1 and 2 were downregulated by tangeretin. Our findings support the possible use of tangeretin for treating allergic asthma.

BJ-1108, a 6-Amino-2,4,5-trimethylpyridin-3-ol analogue, regulates differentiation of Th1 and Th17 cells to ameliorate experimental autoimmune encephalomyelitis

BACKGROUND: CD4+ T cells play an important role in the initiation of an immune response by providing help to other cells. Among the helper T subsets, interferon-γ (IFN-γ)-secreting T helper 1 (Th1) and IL-17-secreting T helper 17 (Th17) cells are indispensable for clearance of intracellular as well as extracellular pathogens. However, Th1 and Th17 cells are also associated with pathogenesis and contribute to the progression of multiple inflammatory conditions and autoimmune diseases. RESULTS: In the current study, we found that BJ-1108, a 6-aminopyridin-3-ol analogue, significantly inhibited Th1 and Th17 differentiation in vitro in a concentration-dependent manner, with no effect on proliferation or apoptosis of activated T cells. Moreover, BJ-1108 inhibited differentiation of Th1 and Th17 cells in ovalbumin (OVA)-specific OT II mice. A complete Freund's adjuvant (CFA)/OVA-induced inflammatory model revealed that BJ-1108 can reduce generation of proinflammatory Th1 and Th17 cells. Furthermore, in vivo studies showed that BJ-1108 delayed onset of disease and suppressed experimental autoimmune encephalomyelitis (EAE) disease progression by inhibiting differentiation of Th1 and Th17 cells. CONCLUSIONS: BJ-1108 treatment ameliorates inflammation and EAE by inhibiting Th1 and Th17 cells differentiation. Our findings suggest that BJ-1108 is a promising novel therapeutic agent for the treatment of inflammation and autoimmune disease.

Treg and Th17 cells in inflammatory periapical disease: a systematic review

Abstract: The process involved in periapical lesions, which occur as an outcome of pulpal necrosis, is regulated by the immune system including regulatory T cells (Treg) and T helper 17 cell (Th17) responses. The objective of this study was to conduct a frequency systematic review to determine the presence of Treg/Th17 responses and the influence of these cells in the progression of chronic inflammatory periapical lesions in humans. A systematic computerized search was carried out in Pubmed, Medline, Web of Science and Scopus electronic databases from their date of inception through the first week of May 2017. In addition, the reference lists of the included articles and the grey literature were hand-searched. Articles that evaluated the presence and influence of Treg/Th17 in the progression of human periapical lesions were included. Study selection and the quality assessment of the included articles (using the Newcastle-Ottawa scale) were carried out by two authors. Fifty-seven titles/abstracts were screened and eight studies met the eligibility criteria and were included in this systematic review. The included studies showed large variation in the type of periapical lesion assessed, mean age, age range, type of experiment and findings regarding the participation of Th17 and Treg in the status of inflammatory periapical lesions. The studies showed the involvement of Treg in the modulation of the inflammatory response in radicular cysts and periapical granulomas. This systematic review highlights the relationship between Treg and Th17 acting in a subtle balance inhibiting or promoting the progression of human periapical lesions.

Linfócitos Th17 e linfócitos T CD4+ multifuncionais em pacientes com lúpus eritematoso sistêmico / Th17 cells and CD4+ multifunctional T cells in patients with systemic lupus erythematosus

Resumo Introdução/Objetivo: Evidências recentes sugerem que anormalidades que envolvem os linfócitos Th17 estão associadas à fisiopatologia do lúpus eritematoso sistêmico (LES). Além disso, os linfócitos T multifuncionais (LTM), ou seja, aqueles que produzem múltiplas citocinas simultaneamente, estão presentes no meio inflamatório e podem estar implicados no processo autoimune observado no LES. No presente estudo, objetiva-se caracterizar o estado funcional dos linfócitos T CD4+ no LES e determinar simultaneamente a concentração de IL-2, IFN-γ e IL-17 em culturas de linfócitos sob estímulos exógenos e autoantigênicos. Pacientes e métodos: Dezoito pacientes com doença ativa, 18 com doença inativa e 14 controles saudáveis foram submetidos à análise do estado funcional dos linfócitos T CD4+. Resultados: Encontrou-se que os pacientes com LES apresentaram uma diminuição na quantidade total de células CD4+, um aumento na quantidade de linfócitos T ativados e um aumento na frequência de linfócitos Th17 em comparação com controles saudáveis (HC). As células LTM tinha frequência aumentada em pacientes com LES e houve um aumento na frequência de LTM trifuncionais em pacientes com LES ativo em comparação com aqueles com LES inativo. Curiosamente, as células MTF produziram quantidades maiores de IFN-γ do que os linfócitos T monofuncionais em pacientes e controles. Conclusão: Analisados em conjunto, esses dados indicam a participação dos linfócitos Th17 recentemente ativados e células MTF na fisiopatologia do LES.

Abstract Introduction/Objective: Recent evidence suggests that abnormalities involving Th17 lymphocytes are associated with the pathophysiology of systemic lupus erythematosus (SLE). In addition, multifunctional T cells (MFT), i. e., those producing multiple cytokines simultaneously, are present in the inflammatory milieu and may be implicated in the autoimmune process observed in SLE. In the present study, we aimed to characterize the functional status of CD4+ T cells in SLE by simultaneously determining the concentration of IL-2, IFN-γ and IL-17 in lymphocyte cultures under exogenous and self-antigenic stimuli. Patients and methods: Eighteen patients with active disease, 18 with inactive disease, and 14 healthy controls had functional status of CD4+ T cells analyzed. Results: We found that SLE patients presented a decreased number of total CD4+ cells, an increased number of activated T cells, and an increased frequency of Th17 cells compared to healthy controls (HC). MFT cells had increased frequency in SLE patients and there was an increased frequency of tri-functional MFT in patients with active SLE compared with those with inactive SLE. Interestingly, MTF cells produced larger amounts of IFNγ than mono-functional T cells in patients and controls. Conclusion: Taken together these data indicate the participation of recently activated Th17 cells and MTF cells in the SLE pathophysiology.

Follicular helper T cell in immunity and autoimmunity

The traditional concept that effector T helper (Th) responses are mediated by Th1/Th2 cell subtypes has been broadened by the recent demonstration of two new effector T helper cells, the IL-17 producing cells (Th17) and the follicular helper T cells (Tfh). These new subsets have many features in common, such as the ability to produce IL-21 and to express the IL-23 receptor (IL23R), the inducible co-stimulatory molecule ICOS, and the transcription factor c-Maf, all of them essential for expansion and establishment of the final pool of both subsets. Tfh cells differ from Th17 by their ability to home to B cell areas in secondary lymphoid tissue through interactions mediated by the chemokine receptor CXCR5 and its ligand CXCL13. These CXCR5+ CD4+ T cells are considered an effector T cell type specialized in B cell help, with a transcriptional profile distinct from Th1 and Th2 cells. The role of Tfh cells and its primary product, IL-21, on B-cell activation and differentiation is essential for humoral immunity against infectious agents. However, when deregulated, Tfh cells could represent an important mechanism contributing to exacerbated humoral response and autoantibody production in autoimmune diseases. This review highlights the importance of Tfh cells by focusing on their biology and differentiation processes in the context of normal immune response to infectious microorganisms and their role in the pathogenesis of autoimmune diseases.

Pathophysiology of psoriasis.

Psoriasis is a chronic inflammatory papulosquamous disease characterized by multiple remissions and relapses. For long, it was believed to be primarily a disorder of keratinization. However, the successful use of traditional immunosupressants and newer immunomodulatory agents in the treatment of psoriasis led to the belief that psoriasis is primarily a disease of Th1 cell immune dysregulation. Recent developments have brought up several new findings such as the role of Th17 cells and evidence of skin barrier dsysfunction in psoriasis, akin to atopic dermatitis. The present review aims to focus on these new developments and explain the pathogenesis of psoriasis on the basis of currently available information.

Pathophysiology of psoriasis.

Psoriasis is a chronic inflammatory papulosquamous disease characterized by multiple remissions and relapses. For long, it was believed to be primarily a disorder of keratinization. However, the successful use of traditional immunosupressants and newer immunomodulatory agents in the treatment of psoriasis led to the belief that psoriasis is primarily a disease of Th1 cell immune dysregulation. Recent developments have brought up several new findings such as the role of Th17 cells and evidence of skin barrier dsysfunction in psoriasis, akin to atopic dermatitis. The present review aims to focus on these new developments and explain the pathogenesis of psoriasis on the basis of currently available information.

In vivo action of IL-27: reciprocal regulation of Th17 and Treg cells in collagen-induced arthritis

Interleukin (IL)-27 is a novel cytokine of the IL-6/IL-12 family that has been reported to be involved in the pathogenesis of autoimmune diseases and has a pivotal role as both a pro- and anti-inflammatory cytokine. We investigated the in vivo effects of IL-27 on arthritis severity in a murine collagen-induced arthritis (CIA) model and its mechanism of action regarding control of regulatory T (Tregs) and IL-17-producing T helper 17 (Th17) cells. IL-27-Fc-treated CIA mice showed a lower severity of arthritis. IL-17 expression in the spleens was significantly decreased in IL-27-Fc-treated CIA mice compared with that in the CIA model. The Th17 population was decreased in the spleens of IL-27-Fc-treated CIA mice, whereas the CD4+CD25+Foxp3+ Treg population increased. In vitro studies revealed that IL-27 inhibited IL-17 production in murine CD4+ T cells, and the effect was associated with retinoic acid-related orphan receptor gammaT and signal transducer and activator of transcription 3 inhibition. In contrast, fluorescein isothiocyanate-labeled forkhead box P3 (Foxp3) and IL-10 were profoundly augmented by IL-27 treatment. Regarding the suppressive capacity of Treg cells, the proportions of CTLA-4+ (cytotoxic T-lymphocyte antigen 4), PD-1+ (programmed cell death protein 1) and GITR+ (glucocorticoid-induced tumor necrosis factor receptor) Tregs increased in the spleens of IL-27-Fc-treated CIA mice. Furthermore, in vitro differentiated Treg cells with IL-27 exerted a more suppressive capacity on T-cell proliferation. We found that IL-27 acts as a reciprocal regulator of the Th17 and Treg populations in CD4+ cells isolated from healthy human peripheral blood mononuclear cells (PBMCs), as well as from humans with rheumatoid arthritis (RA) PBMCs. Our study suggests that IL-27 has the potential to ameliorate overwhelming inflammation in patients with RA through a reciprocal regulation of Th17 and Treg cells.

Alteration of Cytokine Production during Visceral Larva Migrans by Toxascaris leonina in Mice

To determine alteration of immune responses during visceral larva migrans (VLM) caused by Toxascaris leonina at several time points, we experimentally infected mice with embryonated eggs of T. leonina and measured T-helper (Th) cell-related serial cytokine production after infection. At day 5 post infection (PI), most larvae were detected from the lungs, spleen, intestine, and muscle. Expression of thymic stromal lymphopoietin (TSLP) and CCL11 (eotaxin) showed a significant increase in most infected organs, except the intestine. However, expression of the CXCL1 (Gro-alpha) gene was most highly enhanced in the intestine at day 14 PI. Th1-related cytokine secretion of splenocytes showed increases at day 28 PI, and the level showed a decrease at day 42 PI. Th2-related cytokine secretion of splenocytes also showed an increase after infection; in particular, IL-5 level showed a significant increase at day 14 PI, and the level showed a decrease at day 28 PI. However, levels of Th17-related cytokines, IL-6 and IL-17A, showed gradual increases until day 42 PI. In conclusion, Th1, Th2, and Th17-related cytokine production might be important in immune responses against T. leonina VLM in experimental mice.

Obesity aggravates the joint inflammation in a collagen-induced arthritis model through deviation to Th17 differentiation

White fat cells secrete adipokines that induce inflammation and obesity has been reported to be characterized by high serum levels of inflammatory cytokines such as IL-6 and TNF-alpha. Rheumatoid arthritis (RA) is a prototype of inflammatory arthritis, but the relationship between RA and obesity is controversial. We made an obese inflammatory arthritis model: obese collagen-induced arthritis (CIA). C57BL/6 mice were fed a 60-kcal high fat diet (HFD) from the age of 4 weeks and they were immunized twice with type II collagen (CII). After immunization, the obese CIA mice showed higher arthritis index scores and histology scores and a more increased incidence of developing arthritis than did the lean CIA mice. After treatment with CII, mixed lymphocyte reaction also showed CII-specific response more intensely in the obese CIA mice than lean CIA. The anti-CII IgG and anti-CII IgG2a levels in the sera of the obese CIA mice were higher than those of the lean CIA mice. The number of Th17 cells was higher and the IL-17 mRNA expression of the splenocytes in the obese CIA mice was higher than that of the lean CIA mice. Obese CIA mice also showed high IL-17 expression on synovium in immunohistochemistry. Although obesity may not play a pathogenic role in initiating arthritis, it could play an important role in amplifying the inflammation of arthritis through the Th1/Th17 response. The obese CIA murine model will be an important tool when we investigate the effect of several therapeutic target molecules to treat RA.

Genetic controls of Th17 cell differentiation and plasticity

CD4+ T lymphocytes play a major role in regulation of adaptive immunity. Upon activation, naive T cells differentiate into different functional subsets. In addition to the classical Th1 and Th2 cells, several novel effector T cell subsets have been recently identified, including Th17 cells. There has been rapid progress in characterizing the development and function of Th17 cells. Here I summarize and discuss on the genetic controls of their differentiation and emerging evidence on their plasticity. This information may benefit understanding and treating immune diseases.

Higher infiltration by Th17 cells compared with regulatory T cells is associated with severe acute T-cell-mediated graft rejection

The aim of this study was to evaluate whether the Th17 and Treg cell infiltration into allograft tissue is associated with the severity of allograft dysfunction and tissue injury in acute T cell-mediated rejection (ATCMR). Seventy-one allograft tissues with biopsy-proven ATCMR were included. The biopsy specimens were immunostained for FOXP3 and IL-17. The allograft function was assessed at biopsy by measuring serum creatinine (Scr) concentration, and by applying the modified diet in renal disease (MDRD) formula, which provides the estimated glomerular filtration rate (eGFR). The severity of allograft tissue injury was assessed by calculating tissue injury scores using the Banff classification. The average numbers of infiltrating Treg and Th17 cells were 11.6 +/- 12.2 cells/mm2 and 5.6 +/- 8.0 cells/mm2, respectively. The average Treg/Th17 ratio was 5.6 +/- 8.2. The Treg/Th17 ratio was significantly associated with allograft function (Scr and MDRD eGFR) and with the severity of interstitial injury and tubular injury (P < 0.05, all parameters). In separate analyses of the number of infiltrating Treg and Th17 cells, Th17 cell infiltration was significantly associated with allograft function and the severity of tissue injury. By contrast, Treg cell infiltration was not significantly associated with allograft dysfunction or the severity of tissue injury. The results of this study show that higher infiltration of Th17 cell compared with Treg cell is significantly associated with the severity of allograft dysfunction and tissue injury.