Anti-TNF-alpha therapy induces a distinct regulatory T cell population in patients with rheumatoid arthritis via TGF-beta

Exogenous TNFR2 activation protects from acute GvHD via host T reg cell expansion

Activation of TNFR2 with a novel agonist expands T reg cells in vivo and protects allo-HCT recipients from acute GvHD while sparing antilymphoma and antiinfectious properties of transplanted donor T cells.

Donor CD4⁺Foxp3⁺ regulatory T cells (T reg cells) suppress graft-versus-host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (HCT [allo-HCT]). Current clinical study protocols rely on the ex vivo expansion of donor T reg cells and their infusion in high numbers. In this study, we present a novel strategy for inhibiting GvHD that is based on the in vivo expansion of recipient T reg cells before allo-HCT, exploiting the crucial role of tumor necrosis factor receptor 2 (TNFR2) in T reg cell biology. Expanding radiation-resistant host T reg cells in recipient mice using a mouse TNFR2-selective agonist before allo-HCT significantly prolonged survival and reduced GvHD severity in a TNFR2- and T reg cell–dependent manner. The beneficial effects of transplanted T cells against leukemia cells and infectious pathogens remained unaffected. A corresponding human TNFR2-specific agonist expanded human T reg cells in vitro. These observations indicate the potential of our strategy to protect allo-HCT patients from acute GvHD by expanding T reg cells via selective TNFR2 activation in vivo.

In Vivo Expansion of Activated Foxp3+ Regulatory T Cells and Establishment of a Type 2 Immune Response upon IL-33 Treatment Protect against Experimental Arthritis

IL-33 is strongly involved in several inflammatory and autoimmune disorders with both pro- and anti-inflammatory properties. However, its contribution to chronic autoimmune inflammation, such as rheumatoid arthritis, is ill defined and probably requires tight regulation. In this study, we aimed at deciphering the complex role of IL-33 in a model of rheumatoid arthritis, namely, collagen-induced arthritis (CIA). We report that repeated injections of IL-33 during induction (early) and during development (late) of CIA strongly suppressed clinical and histological signs of arthritis. In contrast, a late IL-33 injection had no effect. The cellular mechanism involved in protection was related to an enhanced type 2 immune response, including the expansion of eosinophils, Th2 cells, and type 2 innate lymphoid cells, associated with an increase in type 2 cytokine levels in the serum of IL-33-treated mice. Moreover, our work strongly highlights the interplay between IL-33 and regulatory T cells (Tregs), demonstrated by the dramatic in vivo increase in Treg frequencies after IL-33 treatment of CIA. More importantly, Tregs from IL-33-treated mice displayed enhanced capacities to suppress IFN-γ production by effector T cells, suggesting that IL-33 not only favors Treg proliferation but also enhances their immunosuppressive properties. In concordance with these observations, we found that IL-33 induced the emergence of a CD39(high) Treg population in a ST2L-dependent manner. Our findings reveal a powerful anti-inflammatory mechanism by which IL-33 administration inhibits arthritis development.

Infliximab therapy balances regulatory T cells, tumour necrosis factor receptor 2 (TNFR2) expression and soluble TNFR2 in sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown aetiology that most commonly affects the lungs. Although elevated levels of regulatory T cells (Tregs ) have been reported, the extent to which they play a role in sarcoidosis pathogenesis remains unclear. Tumour necrosis factor (TNF) is thought to be one of the driving forces behind granuloma formation, illustrated by the efficacy of infliximab in severe sarcoidosis. Tregs express TNF receptor 2 (TNFR2) highly. Here, we examined the influence of infliximab therapy on Tregs and (soluble) TNFR2 levels in sarcoidosis, and correlated these with response to therapy. We observed that relative frequencies of Tregs were significantly higher in patients (n = 54) compared to healthy controls (n = 26; median 6·73 versus 4·36%; P < 0·001) and decreased following therapy (4·95; P < 0·001). Baseline TNFR2 expression on Tregs was increased significantly in patients versus controls (99·4 versus 96·2%; P = 0·031), and also in responders to therapy versus non-responders (99·6 versus 97·3%; P = 0·012). Furthermore, baseline soluble TNFR2 (sTNFR2) was higher in responders than in non-responders (mean 174 versus 107 pg/ml; P = 0·015). After treatment, responders showed a significant reduction in sTNFR2 levels in peripheral blood (-44·7 pg/ml; P < 0·001), in contrast to non-responders (+3·59 pg/ml). Our results demonstrated that Treg frequencies and TNFR2 expression on Tregs are increased in sarcoidosis, followed by a decline during infliximab therapy, suggesting a pathophysiological role of this T cell subset. Interestingly, sTNFR2 levels at baseline differed significantly between responders and non-responders, making it a potential marker in predicting which patients might benefit from infliximab.

Adalimumab ameliorates OVA-induced airway inflammation in mice: Role of CD4(+) CD25(+) FOXP3(+) regulatory T-cells

Asthma is a chronic inflammatory heterogeneous disorder initiated by a dysregulated immune response which drives disease development in susceptible individuals. Though T helper 2 (TH2) biased responses are usually linked to eosinophilic asthma, other Th cell subsets induce neutrophilic airway inflammation which provokes the most severe asthmatic phenotypes. A growing evidence highlights the role of T regulatory (Treg) cells in damping abnormal Th responses and thus inhibiting allergy and asthma. Therefore, strategies to induce or augment Treg cells hold promise for treatment and prevention of allergic airway inflammation. Recently, the link between Tumor necrosis factor-α (TNF-α) and Treg has been uncovered, and TNF-α antagonists are increasingly used in many autoimmune diseases. Yet, their benefits in allergic airway inflammation is not clarified. We investigated the effect of Adalimumab, a TNF-α antagonist, on Ovalbumin (OVA)-induced allergic airway inflammation in CD1 mice and explored its impact on Treg cells. Our results showed that Adalimumab treatment attenuated the OVA-induced increase in serum IgE, TH2 and TH1 derived inflammatory cytokines (IL-4 and IFN-γ, respectively) in bronchoalveolar lavage (BAL) fluid, suppressed recruitment of inflammatory cells in BAL fluid and lung, and inhibited BAL fluid neutrophilia. It also ameliorated goblet cell metaplasia and bronchial fibrosis. Splenocytes flow cytometry revealed increased percentage of CD4(+) CD25(+) FOXP3(+) Treg cells by Adalimumab that was associated with increase in their suppressive activity as shown by elevated BAL fluid IL-10. We conclude that the beneficial effects of Adalimumab in this CD1 neutrophilic model of allergic airway inflammation are attributed to augmentation of Treg cell number and activity.

Recent Advances in Defining the Genetic Basis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is the most common inflammatory arthritis and exhibits genetic overlap with other autoimmune and inflammatory disorders. Although predominant associations with the HLA-DRB1 locus have been known for decades, recent data have revealed additional insight into the likely causative variants within HLA-DRB1 as well as within other HLA loci that contribute to disease risk. In addition, more than 100 common variants in non-HLA loci have been implicated in disease susceptibility. Genetic factors are involved not only in the development of RA, but also with various disease subphenotypes, including production and circulating levels of autoantibodies and joint destruction. The major current challenge is to integrate these new data into a precise understanding of disease pathogenesis, including the critical cell types and molecular networks involved as well as interactions with environmental factors. We predict that delineating the functional effects of genetic variants is likely to drive new diagnostic and therapeutic approaches to the disease.

Gene Therapy Induces Antigen-Specific Tolerance in Experimental Collagen-Induced Arthritis

Here, we investigate induction of immunological tolerance by lentiviral based gene therapy in a mouse model of rheumatoid arthritis, collagen II-induced arthritis (CIA). Targeting the expression of the collagen type II (CII) to antigen presenting cells (APCs) induced antigen-specific tolerance, where only 5% of the mice developed arthritis as compared with 95% of the control mice. In the CII-tolerized mice, the proportion of Tregs as well as mRNA expression of SOCS1 (suppressors of cytokine signaling 1) increased at day 3 after CII immunization. Transfer of B cells or non-B cell APC, as well as T cells, from tolerized to naïve mice all mediated a certain degree of tolerance. Thus, sustainable tolerance is established very early during the course of arthritis and is mediated by both B and non-B cells as APCs. This novel approach for inducing tolerance to disease specific antigens can be used for studying tolerance mechanisms, not only in CIA but also in other autoimmune diseases.

Imbalanced immune homeostasis in immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder resulting from low platelet counts caused by inadequate production as well as increased destruction by autoimmune mechanisms. As with other autoimmune disorders, chronic ITP is characterized by perturbations of immune homeostasis with hyperactivated effector cells as well as defective regulatory arm of the adaptive immune system, which will be reviewed here. Interestingly, some ITP treatments are associated with restoring the regulatory imbalance, although it remains unclear whether the immune system is redirected to a state of tolerance once treatment is discontinued. Understanding the mechanisms that result in breakdown of immune homeostasis in ITP will help to identify novel pathways for restoring tolerance and inhibiting effector cell responses. This information can then be translated into developing therapies for averting autoimmunity not only in ITP but also many autoimmune disorders.

Association of anti-Ro/SSA antibody with response to biologics in patients with rheumatoid arthritis

OBJECTIVE

To compare the effectiveness of three different biologics in anti-Ro/SSA antibody-positive and antibody-negative patients with rheumatoid arthritis (RA).

METHODS

The study subjects were 110 biologics naïve patients with RA who started treatment with biologics and examined for anti-Ro/SSA antibody between December 2003 and March 2014. For patients treated with intravenous infliximab (IFX), tocilizumab (TCZ), or abatacept (ABT), we compared the clinical characteristics and changes in composite disease activity index, such as DAS28, SDAI, and CDAI, for 12 months in anti-Ro/SSA antibody-positive and antibody-negative patients.

RESULTS

We examined 59 patients (nine were positive and 50 were negative for anti-Ro/SSA antibody) treated with IFX, 27 patients (5 positive and 22 negative) treated with TCZ, and 24 patients (13 positive and 11 negative) treated with ABT. For patients treated with IFX, parameters of disease activity did not change significantly from baseline in anti-Ro/SSA antibody-positive patients, whereas they improved in antibody-negative patients. On the other hand, treatment with TCZ and ABT significantly decreased disease activity, relative to baseline, in both anti-Ro/SSA antibody-positive and antibody-negative patients. Anti-Ro/SSA antibody-positive patients treated with IFX showed higher frequency of HACA and seroconversion of ANA, and lower serum TGF-β levels.

CONCLUSIONS

Positivity to anti-Ro/SSA in RA seems to confer resistance to IFX via production of HACA and ANA, and low serum TGF-β levels, but not to TCZ and ABT.

Epigallocatechin-3-gallate ameliorates autoimmune arthritis by reciprocal regulation of T helper-17 regulatory T cells and inhibition of osteoclastogenesis by inhibiting STAT3 signaling

The green tea polyphenol epigallocatechin-3-gallate is a potent antioxidant. Here, we describe the effects of epigallocatechin-3-gallate on T cell differentiation and osteoclast differentiation in an animal model of arthritis. Mice with collagen-induced arthritis were injected intraperitoneally with epigallocatechin-3-gallate, 3 times/wk after the primary immunization. Surface markers of T helper 17 cells and regulatory T cells were analyzed by flow cytometry. Flow cytometry, Western blotting, and enzyme-linked immunosorbent assays were used to evaluate the effect of epigallocatechin-3-gallate on cell signaling in the collagen-induced arthritis model. Epigallocatechin-3-gallate decreased the arthritis index and showed protective effects against joint destruction in collagen-induced arthritis mice. The expression of cytokines, oxidative stress proteins, and phosphorylated-signal transducer and activator of transcription-3, 705 and 727, were significantly less in mice treated with epigallocatechin-3-gallate than it was in controls. Epigallocatechin-3-gallate reduced the expression of osteoclast markers in vitro and in vivo relative to the control, and the antiosteoclastic activity was observed in epigallocatechin-3-gallate-treated, interferon-γ knockout mice. The proportion of forkhead box protein 3-positive regulatory T cells was increased in the spleens of mice treated with epigallocatechin-3-gallate compared with control mice, whereas the proportion of T helper 17 cells was reduced. In vitro, the expression of nuclear respiratory factor 2, heme oxygenase-1, and extracellular signal-regulated kinase was increased significantly by epigallocatechin-3-gallate. We demonstrated that the administration of epigallocatechin-3-gallate attenuated the symptoms of arthritis, inhibited osteoclastogenesis and T helper 17 cell activation, and increased the number of regulatory T cells. At the molecular level, the antiarthritic effects of epigallocatechin-3-gallate may be due to induction of phosphorylated-extracellular signal-regulated kinase, nuclear respiratory factor 2, and heme oxygenase-1 and inhibition of signal transducer and activator of transcription-3 activation.

IL-10/IFNγ co-expressing CD4(+) T cells induced by IL-10 DC display a regulatory gene profile and downmodulate T cell responses

Induced regulatory T cells (iTreg) are imperative for tolerance induction and spreading of infectious tolerance. Ex vivo generated tolerogenic dendritic cells (tDCs) have strong therapeutic potential to induce antigen-specific iTreg. We previously demonstrated that IL-10 tDC-primed T cells are very suppressive and produce IL-10. Here, we show that the majority of IL-10(+) T cells co-express IFNγ, giving rise to the question whether these cells are proinflammatory or regulatory. Whole genome gene expression analysis revealed a strong regulatory gene profile and a suppressed Th1 gene profile for IL-10/IFNγ co-expressing CD4(+) T cells. Protein analysis confirmed an extensive regulatory phenotype for IL-10(+)/IFNγ(+) T cells, with specific enhanced expression of GARP and PD-1. In line with these data, isolated IL-10(+)/IFNγ(+) T cells displayed potent suppressive capacity. Thus, IL-10/IFNγ co-expressing CD4(+) T cells induced by IL-10 tDC show dominance of immunomodulation over Th1-mediated immunoactivation and can contribute to induction or spreading of immunological tolerance.

The Interplay Between Monocytes/Macrophages and CD4(+) T Cell Subsets in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation of the synovial lining (synovitis). The inflammation in the RA joint is associated with and driven by immune cell infiltration, synovial hyperproliferation, and excessive production of proinflammatory mediators, such as tumor necrosis factor α (TNFα), interferon γ (IFNγ), interleukin (IL)-1β, IL-6, and IL-17, eventually resulting in damage to the cartilage and underlying bone. The RA joint harbors a wide range of immune cell types, including monocytes, macrophages, and CD4(+) T cells (both proinflammatory and regulatory). The interplay between CD14(+) myeloid cells and CD4(+) T cells can significantly influence CD4(+) T cell function, and conversely, effector vs. regulatory CD4(+) T cell subsets can exert profound effects on monocyte/macrophage function. In this review, we will discuss how the interplay between CD4(+) T cells and monocytes/macrophages may contribute to the immunopathology of RA.

Manipulating regulatory T cells: a promising strategy to treat autoimmunity

CD4(+)CD25(+)Foxp3(+)regulatory T cells (Treg cells) are extremely important in maintaining immune tolerance. Manipulation of Treg cells, especially autoantigen-specific Treg cells is a promising approach for treatments of autoimmune disease since Treg cells may provide the advantage of antigen specificity without overall immune suppression. However, the clinical application of Treg cells has long been limited due to low numbers of Treg cells and the difficulty in identifying their antigen specificity. In this review, we summarize studies that demonstrate regression of autoimmune diseases using Treg cells as therapeutics. We also discuss approaches to generate polyclonal and autoantigen-specific Treg cells in vitro and in vivo. We also discuss our recent study that describes a novel approach of generating autoantigen-specific Treg cells in vivo and restoring immune tolerance by two steps apoptosis-antigen therapy.

Restoration of Foxp3+ Regulatory T-cell Subsets and Foxp3- Type 1 Regulatory-like T Cells in Inflammatory Bowel Diseases During Anti-tumor Necrosis Factor Therapy

BACKGROUND

A defect in regulatory T cells (Tregs) may be involved in the pathogenesis of inflammatory bowel diseases (IBD). Several subsets of human Foxp3+ Tregs (activated and resting Tregs) have now been identified, as well as an IL-10 and IFN-γ double producing Foxp3 type 1 regulatory-like T cell (Tr1L). We have quantified these Tregs in patients with active IBD and during therapy with infliximab (IFX).

METHODS

Blood samples were obtained from healthy controls (n = 54) and patients with active IBD, either before (n = 62) or during IFX therapy (n = 75). Tregs were identified by immunofluorescent staining and flow cytometry analysis. Resting and activated Foxp3+ Tregs can be differentiated from Foxp3+ effector T cells (Foxp3+ Teff) by the expression of CD45RA. Tr1L are identified as CD4+CD45RA-CD25-CD127-Foxp3- T cells.

RESULTS

A numerical deficiency of circulating resting Tregs, activated Treg cells, and Tr1L was documented in patients with active IBD. Baseline levels of these Treg subsets predicted clinical responses to IFX. We documented an upregulation of all 3 subsets during IFX therapy. Moreover, after therapy, significant differences in Treg subsets were seen between responders and nonresponders to IFX. Restoration of Tregs correlated with the clinical and biological response to IFX therapy. Trough serum levels of IFX positively correlated with the proportion of activated Treg cells and Tr1L during therapy.

CONCLUSIONS

IFX therapy, when successful, results in upmodulation of the different types of Treg cells in the blood of patients with IBD. This effect might be relevant for understanding the mechanism of action of anti-TNF agents.

Oral administration of non-absorbable delayed release 6-mercaptopurine is locally active in the gut, exerts a systemic immune effect and alleviates Crohn's disease with low rate of side effects: results of double blind Phase II clinical trial

Therapy for Crohn's disease (CD) with thiopurines is limited by systemic side effects. A novel formulation of fixed-dose, delayed-release 6-mercaptopurine (DR-6MP) was developed, with local effect on the gut immune system and minimal absorption. The aim of this study was to evaluate the safety and efficacy of DR-6MP in patients with moderately severe CD compared to systemically delivered 6-mercaptopurine (Purinethol). Seventy CD patients were enrolled into a 12-week, double-blind controlled trial. The primary end-point was the percentage of subjects with clinical remission [Crohn's Disease Activity Index (CDAI) < 150] or clinical response (100-point CDAI reduction). Twenty-six (56·5%) and 13 (54·2%) subjects from the DR-6MP and Purinethol cohorts, respectively, completed the study. DR-6MP had similar efficacy to Purinethol following 12 weeks of treatment. However, the time to maximal clinical response was 8 weeks for DR-6MP versus 12 weeks for Purinethol. A higher proportion of patients on DR-6MP showed clinical remission at week 8. A greater improvement in Inflammatory Bowel Disease Questionnaire (IBDQ) score was noted in the DR-6MP group. DR-6MP led to a decrease of CD62(+) expression on T cells, implying a reduction of lymphocyte adhesion to site of inflammation. DR-6MP was safer than Purinethol, with significantly fewer adverse events (AEs). There was no evidence of drug-induced leucopenia in the DR-6MP group; the proportion of subjects who developed hepatotoxicity was lower for the DR-6MP. Non-absorbable DR-6MP is safe and biologically active in the gut. It is clinically effective, exerting a systemic immune response with low systemic bioavailability and a low incidence of side effects.

Targeting VEGF-A with a vaccine decreases inflammation and joint destruction in experimental arthritis

OBJECTIVES

Inflammation and angiogenesis are two tightly linked processes in arthritis, and therapeutic targeting of pro-angiogenic factors may contribute to control joint inflammation and synovitis progression. In this work, we explored whether vaccination against vascular endothelial growth factor (VEGF) ameliorates collagen-induced arthritis (CIA).

METHODS

Anti-VEGF vaccines were heterocomplexes consisting of the entire VEGF cytokine (or a VEGF-derived peptide) linked to the carrier protein keyhole limpet hemocyanin (KLH). Two kinds of vaccines were separately tested in two independent experiments of CIA. In the first, we tested a kinoid of the murine cytokine VEGF (VEGF-K), obtained by conjugating VEGF-A to KLH. For the second, we selected two VEGF-A-derived peptide sequences to produce heterocomplexes (Vpep1-K and Vpep2-K). DBA/1 mice were immunized with either VEGF-K, Vpep1-K, or Vpep2-K, before CIA induction. Clinical and histological scores of arthritis, anti-VEGF, anti-Vpep Ab titers, and anti-VEGF Abs neutralizing capacity were determined.

RESULTS

Both VEGF-K and Vpep1-K significantly ameliorated clinical arthritis scores and reduced synovial inflammation and joint destruction at histology. VEGF-K significantly reduced synovial vascularization. None of the vaccines reduced anti-collagen Ab response in mice. Both VEGF-K and Vpep1-K induced persistently high titers of anti-VEGF Abs capable of inhibiting VEGF-A bioactivity.

CONCLUSION

Vaccination against the pro-angiogenic factor VEGF-A leads to the production of anti-VEGF polyclonal Abs and has a significant anti-inflammatory effect in CIA. Restraining Ab response to a single peptide sequence (Vpep1) with a peptide vaccine effectively protects immunized mice from joint inflammation and destruction.

The role of cytokines in the pathogenesis of rheumatoid arthritis--Practical and potential application of cytokines as biomarkers and targets of personalized therapy

Rheumatoid arthritis (RA), as a common chronic disease leading to severe disability, requires early diagnosis and introduction of proper treatment. Deregulation in the cytokine network plays an undoubtedly crucial role in the pathogenesis of RA. The understanding of the role of cytokines in RA can be used for patients' benefit. Technological advances had already allowed introduction of the tailor-made cytokine-targeted therapies (so far anti-TNF, anti-IL-1 and anti-IL-6) into clinical practice. This type of treatment is currently developing very fast. Moreover, cytokines are considered to be potential powerful biomarkers of RA with roles predicted to grow in the future. Detailed understanding of the cytokine balance in RA may assist both the diagnostic process and therapy.

Paradoxical Expansion of Th1 and Th17 Lymphocytes in Rheumatoid Arthritis Following Infliximab Treatment: a Possible Explanation for a Lack of Clinical Response

PURPOSE

The immunogenicity of anti-TNF-α drugs may affect their safety and efficacy. Infliximab (IFX), a chimeric monoclonal antibody, induces antibody formation in up to 60% of cases. Some studies have suggested the involvement of a Th1 response to TNFα blockers following immunization, but the triggering of Th17 responses has never been reported. The aim of this study is to investigate whether the immunogenicity of IFX affects the Th1, Th17 and Treg compartments in rheumatoid arthritis (RA) patients failing IFX therapy, and verify whether this may be responsible for treatment failure.

METHODS

The study involved 55 patients with RA (15 treatment-naïve patients; 20 IFX responders; 20 IFX non-responders) and 10 healthy controls. PBMCs were cultured in the presence/absence of IFX, and the variations in the percentage of Th1, Th17 and Treg lymphocytes following IFX treatment were analysed.

RESULTS

IFX-specific Th1 and Th17 responses and an increase in IL-21 production were observed in patients failing IFX (p < 0.01, p < 0.05, and p < 0.01 respectively). In contrast, IFX incubation reduced significantly Th1 and Th17 responses and IL-21 production (p < 0.05) in successfully-treated subjects, but did not affect these responses in healthy controls or treatment-naïve patients.

CONCLUSIONS

RA patients may have impaired peripheral tolerance, which could favour the development of an aberrant immunological response to biological drugs. The loss of therapeutic effectiveness of IFX and the onset of adverse events may be due to a paradoxical activation of Th17 or Th1 lymphocytes following sensitisation, thus worsening the patients' inflammatory status.

Methotrexate Restores Regulatory T Cell Function Through Demethylation of the FoxP3 Upstream Enhancer in Patients With Rheumatoid Arthritis

OBJECTIVE

We have previously shown, in a cohort of untreated rheumatoid arthritis (RA) patients, that the suppressive function of Treg cells is defective. However, other studies in cohorts of patients with established RA have shown that Treg cell function is normal. We hypothesized that treatment may restore Treg cell function and lead to reduced disease activity. The aim of this study was to investigate whether treatment with methotrexate (MTX) can result in epigenetic changes that lead to restoration of the Treg cell suppressive function in RA.

METHODS

Peripheral blood samples from RA patients were assessed using (3) H-thymidine incorporation to measure Treg cell suppression of T cell proliferation, and by enzyme-linked immunosorbent assay to determine Treg cell suppression of interferon-γ production. CTLA-4 and FoxP3 expression was measured by flow cytometry and quantitative polymerase chain reaction (qPCR) in Treg cells from healthy individuals and RA patients. CD4+ T cells isolated from healthy individuals were cultured with interleukin-2 (IL-2), IL-6, and tumor necrosis factor α in the presence or absence of MTX, and FoxP3 expression was determined using qPCR and flow cytometry. Methylation of the FOXP3 upstream enhancer was analyzed by bisulfite sequencing PCR.

RESULTS

Defective Treg cell function was observed only in RA patients who had not been treated with MTX, whereas Treg cells from MTX-exposed RA patients had restored suppressive function. This restored suppression was associated with increased expression of FoxP3 and CTLA-4 in Treg cells. Bisulfite sequencing PCR of Treg cells cultured in MTX revealed a significant reduction in methylation of the FOXP3 upstream enhancer.

CONCLUSION

This study identifies a novel mechanism of action of MTX, in which treatment of RA patients with MTX restores defective Treg cell function through demethylation of the FOXP3 locus, leading to a subsequent increase in FoxP3 and CTLA-4 expression.

Expression of TIM-3, Human β-defensin-2, and FOXP3 and Correlation with Disease Activity in Pediatric Crohn's Disease with Infliximab Therapy

BACKGROUND/AIMS

This study investigated the expression of T cell immunoglobulin- and mucin-domain-containing molecule 3 (TIM-3), human β-defensin (HBD)-2, forkhead box protein 3 (FOXP3), and the frequency of CD4(+) CD25(+) FOXP3(+) regulatory T cells (Tregs) in children with Crohn's disease (CD) during infliximab therapy.

METHODS

We enrolled 20 CD patients who received infliximab treatment for 1 year. Peripheral blood and colonic mucosal specimens were collected from all CD patients and from healthy control individuals.

RESULTS

A significant difference in TIM-3 mRNA expression was evident in peripheral blood mononuclear cells and colonic mucosa between CD patients before infliximab therapy and the healthy controls (p<0.001 and p=0.005, respectively). A significant difference in HBD-2 mRNA expression was found in colonic mucosa between CD patients before infliximab therapy and the healthy controls (p=0.013). In the active phase of CD, at baseline, the median percentage of T cells that were CD25(+) FOXP3(+) was 1.5% (range, 0.32% to 3.49%), which increased after inflixmab treatment for 1 year to 2.2% (range, 0.54% to 5.02%) (p=0.008).

CONCLUSIONS

Our study suggests that both the adaptive and innate immune systems are closely linked to each other in CD pathogenesis. And the results of our study indicate that it could be a useful therapeutic tool, where restoration of TIM-3, HBD-2 and the function of Tregs may repair the dysfunctional immunoregulation in CD.

CD11c-mediated deletion of Flip promotes autoreactivity and inflammatory arthritis

Dendritic cells (DCs) are critical for immune homeostasis. To target DCs, we generated a mouse line with Flip deficiency in cells that express cre under the CD11c promoter (CD11c-Flip-KO). CD11c-Flip-KO mice spontaneously develop erosive, inflammatory arthritis, resembling rheumatoid arthritis, which is dramatically reduced when these mice are crossed with Rag^−/− mice. The CD8α⁺ DC subset is significantly reduced, along with alterations in NK cells and macrophages. Autoreactive CD4⁺ T cells and autoantibodies specific for joint tissue are present, and arthritis severity correlates with the number of autoreactive CD4⁺ T cells and plasmablasts in the joint-draining lymph nodes. Reduced T regulatory cells (Tregs) inversely correlate with arthritis severity, and the transfer of Tregs ameliorates arthritis. This KO line identifies a model that will permit in depth interrogation of the pathogenesis of rheumatoid arthritis, including the role of CD8α⁺ DCs and other cells of the immune system.

Dendritic cells are critical for initiation of immune responses and for induction of tolerance. Here the authors show that deletion of survival factor c-flip in CD11c-expressing cells subset perturbs CD8a⁺ dendritic cell, NK and macrophage pools, and leads to development of autoimmune arthritis.

The therapeutic potential of regulatory T cells for the treatment of autoimmune disease

INTRODUCTION

Immune tolerance remains the holy grail of therapeutic immunology in the fields of organ and tissue transplant rejection, autoimmune diseases, and allergy and asthma. We have learned that FoxP3(+)CD4(+) regulatory T cells play a vital role in both the induction and maintenance of self-tolerance.

AREAS COVERED

In this opinion piece, we highlight regulatory T cells (Treg) cell biology and novel immune treatments to take advantage of these cells as potent therapeutics. We discuss the potential to utilize Treg and Treg-friendly therapies to replace current general immunosuppressives and induce tolerance as a path towards a drug-free existence without associated toxicities.

EXPERT OPINION

Finally, we opine on the fact that biomedicine sits on the cusp of a new revolution: the use of human cells as versatile therapeutic engines. We highlight the challenges and opportunities associated with the development of a foundational cellular engineering science that provides a systematic framework for safely and predictably regulating cellular behaviors. Although Treg therapy has become a legitimate clinical treatment, development of the therapy will require a better understanding of the underlying Treg biology, manufacturing advances to promote cost effectiveness and combinations with other drugs to alter the pathogenicity/regulatory balance.

Altered immunoregulation in rheumatoid arthritis: the role of regulatory T cells and proinflammatory Th17 cells and therapeutic implications

In recent years several studies investigated the role of T lymphocyte subpopulations in the pathogenesis of rheumatoid arthritis (RA). Pathogenic Th17 cells mediate pannus growth, osteoclastogenesis, and synovial neoangiogenesis; hence they are key players in the development of the disease. On the other hand, regulatory T (Treg) cells are a T cell subset whose peculiar function is to suppress autoreactive lymphocytes. The imbalance between Th17 and Treg cells has been identified as a crucial event in the pathogenesis of RA. In addition, the effects of currently employed RA therapeutic strategies on these lymphocyte subpopulations have been extensively investigated. This review article aims to discuss current knowledge on Treg and Th17 cells in RA and possible implications of their therapeutic targeting in this disorder.

Immunoregulatory role of IL-35 in T cells of patients with rheumatoid arthritis

OBJECTIVE

IL-35 is the most recently identified member of the IL-12 family. It consists of EBV-induced gene 3 (EBI3) and IL-12α chain p35. We investigated whether IL-35 enhances the in vitro immunosuppressive function of peripheral blood isolated from patients with RA.

METHODS

Peripheral blood was harvested from 17 active and 10 inactive RA patients and IL-35 concentrations were quantified using an ELISA. An expression vector containing IL-35 with a FLAG tag at the carboxyl-terminus was constructed by covalently linking EBI3 and IL-12α (p35). The function of IL-35 was then evaluated in a suppression assay using T cells isolated from human RA patients with CD2, CD3 and CD28 antibodies.

RESULTS

Serum IL-35 levels and the number of Treg were decreased significantly in patients with active RA. There was a significant correlation between serum IL-35 and the 28-joint DAS with ESR (DAS28-ESR) in patients with active RA. IL-35 treatment enhanced the regulatory function, suppressing the levels of inflammatory cytokines such as IL-17 and IFN-γ and the cellular growth of effector T cells stimulated by conjugation with CD2, CD3 and CD28.

CONCLUSION

These data revealed that IL-35 might suppress T cell activation during the peripheral immune responses of RA. Therefore our data suggest that IL-35 might have multiple therapeutic targets.

Specific therapy to regulate inflammation in rheumatoid arthritis: molecular aspects

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which persistent inflammation of synovial tissue results in a progressive functional decline of the joint and premature mortality. TNF inhibitors were the first biological disease-modifying antirheumatic drugs (DMARDs) used to treat RA. Since then, new biological drugs have emerged, such as inhibitors of IL-1, IL-6 and others, with different mechanisms of action that include the depletion of B cells and the inhibition of T-cell costimulation. Recently, RA treatments have incorporated the use of synthetic DMARDs. This review describes the molecular aspects of the mechanisms of action of biological and synthetic DMARDs, discusses the adverse effects and limitations of established therapies and analyses the alternative approaches to RA treatment.

B cells expressing IFN-γ suppress Treg-cell differentiation and promote autoimmune experimental arthritis

Clinical efficacy in the treatment of rheumatoid arthritis with anti-CD20 (Rituximab)-mediated B-cell depletion has garnered interest in the mechanisms by which B cells contribute to autoimmunity. We have reported that B-cell depletion in a murine model of proteoglycan-induced arthritis (PGIA) leads to an increase in Treg cells that correlate with decreased autoreactivity. Here, we demonstrate that the increase in Treg cells after B-cell depletion is due to an increase in the differentiation of naïve CD4(+) T cells into Treg cells. Since the development of PGIA is dependent on IFN-γ and B cells are reported to produce IFN-γ, we hypothesized that B-cell-specific IFN-γ plays a role in the development of PGIA. Accordingly, mice with B-cell-specific IFN-γ deficiency were as resistant to the induction of PGIA as mice that were completely IFN-γ deficient. Importantly, despite a normal frequency of IFN-γ-producing CD4(+) T cells, B-cell-specific IFN-γ-deficient mice exhibited a higher percentage of Treg cells compared with that in WT mice. These data indicate that B-cell IFN-γ production inhibits Treg-cell differentiation and exacerbates arthritis. Thus, we have established that IFN-γ, specifically derived from B cells, uniquely contributes to the pathogenesis of autoimmunity through prevention of immunoregulatory mechanisms.

The impact of biological therapy on regulatory T cells in rheumatoid arthritis

Regulatory T cells (Treg) are functionally defective in patients with RA. Restoring their function may not only control inflammation but also restore tolerance in these patients. Biologic therapies have been tremendously successful in treating RA. Here we review numerous reports suggesting that these immunomodulatory therapies have an impact on Treg and that this may contribute to their beneficial effects. Better understanding of their mode of action may not only lead to improvements in therapies and sustained remission but also enable the development of biomarkers of response, which would be the first steps towards personalized medicine.

Induced CD8+FoxP3+ Treg cells in rheumatoid arthritis are modulated by p38 phosphorylation and monocytes expressing membrane tumor necrosis factor α and CD86

OBJECTIVE

Limiting the severity of inflammation and promoting its eventual resolution are vital for protecting host tissues both in autoimmunity and chronic infection. The aim of this study was to determine the suitability of repurposing anti-CD3 monoclonal antibody (mAb) therapy for rheumatoid arthritis (RA) by analyzing its ability to induce CD8+FoxP3+ Treg cells from peripheral blood mononuclear cells (PBMCs).

METHODS

Anti-CD3 mAb was cultured with RA PBMCs to induce CD8+FoxP3+ Treg cells, which were analyzed by flow cytometry to determine their phenotype. Treg cell induction was investigated via neutralization or blocking antibodies, cellular depletion, or ImageStream technology. Blotting was used to determine the signaling pathways involved in CD8+FoxP3+ Treg cell induction. Suppression of CD4+ T cell effector responses was assessed by Treg cell suppression assays and Mosaic enzyme-linked immunosorbent assay.

RESULTS

Potent CD8+FoxP3+ Treg cells were induced from RA PBMCs by anti-CD3 mAb. Unlike their CD4+ counterparts, CD8+FoxP3+ Treg cells inhibited Th17 responses in a contact-dependent manner, thereby functioning to limit a wider range of inflammatory pathways. CD8+FoxP3+ Treg cell induction was supported both by p38 phosphorylation intrinsic to naive CD8+ T cells and by monocytes via CD86 and membrane tumor necrosis factor α (TNFα). Artificially increasing monocyte membrane TNFα or inhibiting CD8+ T cell p38 phosphorylation drove FoxP3 expression in a subset of initially unresponsive CD8+ T cells.

CONCLUSION

These data define an unknown mechanism of CD8+FoxP3+ Treg cell induction by anti-CD3 mAb, which could be combined with a p38 inhibitor to improve therapeutic efficacy in RA patients and resolve chronic inflammation via the restoration of tolerance.

Regulatory T-cell homeostasis: steady-state maintenance and modulation during inflammation

Regulatory T (Treg) cells play a vital role in the prevention of autoimmunity and the maintenance of self-tolerance, but these cells also have an active role in inhibiting immune responses during viral, bacterial, and parasitic infections. Although excessive Treg activity can lead to immunodeficiency, chronic infection, and cancer, too little Treg activity results in autoimmunity and immunopathology and impairs the quality of pathogen-specific responses. Recent studies have helped define the homeostatic mechanisms that support the diverse pool of peripheral Treg cells under steady-state conditions and delineate how the abundance and function of Treg cells changes during inflammation. These findings are highly relevant for developing effective strategies to manipulate Treg cell activity to promote allograft tolerance and treat autoimmunity, chronic infection, and cancer.

TNFα promotes Th17 cell differentiation through IL-6 and IL-1β produced by monocytes in rheumatoid arthritis

TNFα plays an important role in autoimmune pathogenesis and is the main therapeutic target of rheumatoid arthritis. However, its underlying mechanism is not completely understood. In this study, we described that Th17 cells were accumulated in synovial fluid, which was attributable to TNFα aberrantly produced in rheumatoid synovium. Interestingly, TNFα cannot induce IL-17 production of CD4⁺ T cells directly, but through the monocytes high levels of IL-1β and IL-6 in a TNFRI and TNFRII dependent manner from the active RA patients are produced. TNFα was shown to enhance the phosphorylation level of STAT3 and the expression level of transcription factor RORC of CD4⁺ T cells when cultured with CD14⁺ monocytes. Treatment with an approved TNFα blocking antibody showed marked reduction in the levels of IL-6, IL-1β, and IL-17 and the expression level of STAT3 phosphorylation in relation to Th17 cell differentiation in patients with rheumatoid arthritis. The study provides new evidence supporting the critical role of TNFα in the pathogenic Th17 cell differentiation in rheumatoid arthritis.

Update on research and clinical translation on specific clinical areas: From bench to bedside: How insight in immune pathogenesis can lead to precision medicine of severe juvenile idiopathic arthritis

Despite the enormous progress in the treatment of juvenile idiopathic arthritis (JIA), innovations based on true bench-to-bedside research, performed in JIA patients, are still scarce. This chapter describes novel developments in which clinical innovations go hand in hand with basic discoveries. For the purpose of this review, we will mainly focus on developments in severe forms of JIA, most notably systemic JIA and polyarticular JIA. However, also in less severe forms of JIA, such as oligoarticular JIA, better insight will help to improve diagnosis and treatment. Facilitating the transition from bench to bedside will prove crucial for addressing the major challenges in JIA management. If successful, it will set new standards for a safe, targeted and personalized therapeutic approach for children with JIA.

Utilizing regulatory T cells against rheumatoid arthritis

Regulatory T (Treg) cells are essential for normal immune surveillance systems, and their dysfunction leads to development of diseases, such as autoimmune disorders. CD4⁺CD25⁺ Treg cells are well-known suppressive cells, which express the transcription factor Foxp3, are indispensable for the maintenance of immune self-tolerance and homeostasis by suppressing aberrant or excessive immune response. Other Foxp3⁻ Treg cells include Tr1, Th3, CD8⁺CD28^−/−, and Qa1-restricted T cells; however, the contribution of these Treg cells to self-tolerance, immune homeostasis as well as preventing autoimmunity is not well defined. Here, we discuss the phenotypes and function of Foxp3⁺ Treg cells and the potential use of such Treg cells against rheumatoid arthritis (RA). Of note, even though most expanded populations of Foxp3⁺ Treg cells exhibit suppressive activity, tissue-associated or antigen-specific Treg cells appear superior in suppressing local autoimmune disorders such as RA. In addition, utilizing tissue-associated Foxp3⁺ Treg cells from stem cells may stable Foxp3 expression and avoid induction of a potentially detrimental systemic immunosuppression.

Interleukin-6 receptor blockade enhances CD39+ regulatory T cell development in rheumatoid arthritis and in experimental arthritis

OBJECTIVE

The rationale for blocking interleukin-6 (IL-6) in rheumatoid arthritis (RA) lies chiefly in the proinflammatory effect of this cytokine. Few studies have evaluated the consequences of anti-IL-6 receptor (IL-6R) antibody treatment on Treg cells. This study was undertaken to elucidate the mechanism of action of anti-IL-6R antibody treatment by studying the effects on Treg cells in an experimental arthritis model and in patients with RA.

METHODS

Mice with collagen-induced arthritis (CIA) were treated with a mouse anti-IL-6R antibody (MR16-1), and changes in Treg, Th1, and Th17 cells were assessed at key time points during the course of the disease. Peripheral blood from 15 RA patients was collected on day 0 and after 3 months of tocilizumab treatment for flow cytometry analysis of Th17 and Treg cells.

RESULTS

In MR16-1-treated mice, Th17 cell frequencies were unchanged, whereas Treg cell frequencies were increased. The Treg cell phenotype showed marked changes, with an increase in the frequency of CD39+ Treg cells in the lymph nodes and spleen. Interestingly, similar CD39+ Treg cell expansion was observed in RA patients who were tocilizumab responders at 3 months, with no change in Th17 cell frequency. Moreover, fluorescence-activated cell-sorted CD39+ Treg cells from responder RA patients were functionally able to suppress the proliferation of conventional T cells.

CONCLUSION

In both CIA and RA, the frequency of functionally suppressive CD39+ Treg cells is increased as a result of anti-IL-6R treatment, whereas Th17 cells are unaffected. The modification of Treg cell frequency and phenotype may be one of the mechanisms involved in the therapeutic effect of IL-6 blockade in RA.

Type 1 regulatory T cells specific for collagen type II as an efficient cell-based therapy in arthritis

Introduction

Regulatory T (Treg) cells play a crucial role in preventing autoimmune diseases and are an ideal target for the development of therapies designed to suppress inflammation in an antigen-specific manner. Type 1 regulatory T (Tr1) cells are defined by their capacity to produce high levels of interleukin 10 (IL-10), which contributes to their ability to suppress pathological immune responses in several settings. The aim of this study was to evaluate the therapeutic potential of collagen type II–specific Tr1 (Col-Treg) cells in two models of rheumatoid arthritis (RA) in mice.

Methods

Col-Treg clones were isolated and expanded from collagen-specific TCR transgenic mice. Their cytokine secretion profile and phenotype characterization were studied. The therapeutic potential of Col-Treg cells was evaluated after adoptive transfer in collagen-antibody– and collagen-induced arthritis models. The in vivo suppressive mechanism of Col-Treg clones on effector T-cell proliferation was also investigated.

Results

Col-Treg clones are characterized by their specific cytokine profile (IL-10^highIL-4^negIFN-γ^int) and mediate contact-independent immune suppression. They also share with natural Tregs high expression of GITR, CD39 and granzyme B. A single infusion of Col-Treg cells reduced the incidence and clinical symptoms of arthritis in both preventive and curative settings, with a significant impact on collagen type II antibodies. Importantly, injection of antigen-specific Tr1 cells decreased the proliferation of antigen-specific effector T cells in vivo significantly.

Conclusions

Our results demonstrate the therapeutic potential of Col-Treg cells in two models of RA, providing evidence that Col-Treg could be an efficient cell-based therapy for RA patients whose disease is refractory to current treatments.

Infliximab for intensification of primary therapy for Kawasaki disease: a phase 3 randomised, double-blind, placebo-controlled trial

BACKGROUND

Kawasaki disease, the most common cause of acquired heart disease in developed countries, is a self-limited vasculitis that is treated with high doses of intravenous immunoglobulin. Resistance to intravenous immunoglobulin in Kawasaki disease increases the risk of coronary artery aneurysms. We assessed whether the addition of infliximab to standard therapy (intravenous immunoglobulin and aspirin) in acute Kawasaki disease reduces the rate of treatment resistance.

METHODS

We undertook a phase 3, randomised, double-blind, placebo-controlled trial in two children's hospitals in the USA to assess the addition of infliximab (5 mg per kg) to standard therapy. Eligible participants were children aged 4 weeks-17 years who had a fever (temperature ≥38·0°C) for 3-10 days and met American Heart Association criteria for Kawasaki disease. Participants were randomly allocated in 1:1 ratio to two treatment groups: infliximab 5 mg/kg at 1 mg/mL intravenously over 2 h or placebo (normal saline 5 mL/kg, administered intravenously). Randomisation was based on a randomly permuted block design (block sizes 2 and 4), stratified by age, sex, and centre. Patients, treating physicians and staff, study team members, and echocardiographers were all masked to treament assignment. The primary outcome was the difference between the groups in treatment resistance defined as a temperature of 38·0°C or higher at 36 h to 7 days after completion of the infusion of intravenous immunoglobulin. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00760435.

FINDINGS

196 patients were enrolled and randomised: 98 to the infliximab group and 98 to placebo. One patient in the placebo group was withdrawn from the study because of hypotension before receiving treatment. Treatment resistance rate did not differ significantly (11 [11·2%] for infliximab and 11 [11·3%] for placebo; p=0·81). Compared with the placebo group, participants given infliximab had fewer days of fever (median 1 day for infliximab vs 2 days for placebo; p<0·0001). At week 2, infliximab-treated patients had greater mean reductions in erythrocyte sedimentation rate (p=0·009) and a two-fold greater decrease in Z score of the left anterior descending artery (p=0·045) than did those in the placebo group, but this difference was not significant at week 5. Participants in the infliximab group had a greater mean reduction in C-reactive protein concentration (p=0·0003) and in absolute neutrophil count (p=0·024) at 24 h after treatment than did those given placebo, but by week 2 this difference was not significant. At week 5, none of the laboratory values differed significantly compared with baseline. No significant differences were recorded between the two groups at any timepoint in proximal right coronary artery Z scores, age-adjusted haemoglobin values, duration of hospital stay, or any other laboratory markers of inflammation measured. No reactions to intravenous immunoglobulin infusion occurred in patients treated with infliximab compared with 13 (13·4%) patients given placebo (p<0·0001). No serious adverse events were directly attributable to infliximab infusion.

INTERPRETATION

The addition of infliximab to primary treatment in acute Kawasaki disease did not reduce treatment resistance. However, it was safe and well tolerated and reduced fever duration, some markers of inflammation, left anterior descending coronary artery Z score, and intravenous immunoglobulin reaction rates.

FUNDING

US Food and Drug Administration, Robert Wood Johnson Foundation, and Janssen Biotech.

Caerulomycin A enhances transforming growth factor-β (TGF-β)-Smad3 protein signaling by suppressing interferon-γ (IFN-γ)-signal transducer and activator of transcription 1 (STAT1) protein signaling to expand regulatory T cells (Tregs)

Cytokines play a very important role in the regulation of immune homeostasis. Regulatory T cells (Tregs) responsible for the generation of peripheral tolerance are under the tight regulation of the cytokine milieu. In this study, we report a novel role of a bipyridyl compound, Caerulomycin A (CaeA), in inducing the generation of Tregs. It was observed that CaeA substantially up-regulated the pool of Tregs, as evidenced by an increased frequency of CD4(+) Foxp3(+) cells. In addition, CaeA significantly suppressed the number of Th1 and Th17 cells, as supported by a decreased percentage of CD4(+)/IFN-γ(+) and CD4(+)/IL-17(+) cells, respectively. Furthermore, we established the mechanism and observed that CaeA interfered with IFN-γ-induced STAT1 signaling by augmenting SOCS1 expression. An increase in the TGF-β-mediated Smad3 activity was also noted. Furthermore, CaeA rescued Tregs from IFN-γ-induced inhibition. These results were corroborated by blocking Smad3 activity, which abolished the CaeA-facilitated generation of Tregs. In essence, our results indicate a novel role of CaeA in inducing the generation of Tregs. This finding suggests that CaeA has enough potential to be considered as a potent future drug for the treatment of autoimmunity.

Selective depletion of regulatory T cell subsets by docetaxel treatment in patients with nonsmall cell lung cancer

Regulatory T (Treg) cells are potent suppressors that maintain immune homeostasis. Accumulation of Treg can inhibit effective immune responses in cancer patients, leading to tumor development and progression. Despite direct cytotoxicity, several chemotherapeutic drugs have been reported to deplete Treg cells for better prognosis for cancer patients. Treg cells are a heterogenous population with at least three different subsets, nonsuppressive, resting, and activated Treg cells. However, the characteristics of Treg cell subsets in lung cancer patients and how chemotherapy affects Treg cells remain elusive. In this study, we first analyzed Treg cell subsets in peripheral blood samples from 40 nonsmall cell lung cancer (NSCLC) patients and 20 healthy donors. Treg cells, specifically activated Treg cell subset, significantly increased in patients with NSCLC. Compared to nonsuppressive Treg cells, activated Treg cells expressed higher level of CD39 and predominantly produced inhibitory cytokines. In vitro assay showed that docetaxel reduced all three subsets of Treg cells. More importantly, we found docetaxel-based chemotherapy significantly decreased all three Treg subsets after 4 cycles of treatment in 17 NSCLC patients. Taken together, this study revealed dynamic changes of various Treg cell subsets in NSCLC patients before and after chemotherapy, providing activated Treg cells as a potential target for chemotherapy.

Inhibition of TNF receptor signaling by anti-TNFα biologicals primes naïve CD4(+) T cells towards IL-10(+) T cells with a regulatory phenotype and function

TNFα is a potent pro-inflammatory cytokine playing a pivotal role in several autoimmune diseases. Little is known about the mechanism of TNFα blocking agents on naïve T cell differentiation. Here, we report that neutralizing TNFα during priming of naïve CD4(+) T cells by dendritic cells favors development of IL-10(+) T helper cells. TNFα counteracts IL-10(+) T cell priming mainly via TNFRI receptor signaling. While initial T cell activation was not affected, neutralization of TNFα negatively affected sustained T cell differentiation in later stages of T cell priming. Whole genome gene expression analysis revealed an extended regulatory gene profile for anti-TNFα-treated T cells. Indeed, neutralizing TNFα during naïve T cell priming enhanced the suppressive function of anti-TNFα-treated T cells. Taken together, inhibition of TNFα-TNFR interaction shifts the balance of Th cell differentiation towards IL-10 expressing suppressive T cells, which may be one of the beneficial mechanisms in TNFα blocking therapies.

Current and potential immune therapies and vaccines in the management of psoriasis

Psoriasis is a chronic, immune skin disease associated with significant morbidity. Development of psoriasis is influenced by numerous genes, one allele is HLA-CW*0602. Other genes and single nucleotide polymorphisms affect immunologic pathways and antimicrobial peptide synthesis. Dendritic cells initiate psoriasis by activating T-cells toward a Th1 and Th17 response, with increased cytokines including TNF-α, IL-6, -12, -17, -22, and -23. IL-22 appears to promote keratinocyte dedifferentiation and increased antimicrobial peptide synthesis while TNF-α and IL-17 induce leukocyte localization within the psoriatic plaque. These recent insights identifying key cytokine pathways have led to the development of inhibitors with significant efficacy in the treatment of psoriasis. While a strategy for vaccine modulation of the immune response in psoriasis is in progress, with new technology they may provide a cost-effective long-term treatment that may induce tolerance or targeted self-inhibition for patients with autoimmune disorders, such as psoriasis.