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Objectives TNF-induced activation of fibroblast-like synoviocytes (FLS) is a critical determinant for synovial inflammation and joint destruction in RA. The detrimental role of TNF-receptor 1 (TNFR1) has thoroughly been characterized. The contributions of TNFR2, however, are largely unknown. This study was performed to delineate the role of TNFR2 in human FLS activation. Methods TNFR2 expression in synovial tissue samples was determined by immunohistochemistry. Expression of TNFR2 was silenced using RNAi or CRISPR/Cas9 technologies. Global transcriptional changes were determined by RNA-seq. QPCR, ELISA and immunoblotting were used to validate RNA-seq results and to uncover pathways operating downstream of TNFR2 in FLS. Results TNFR2 expression was increased in RA when compared with OA synovial tissues. In particular, RA-FLS demonstrated higher levels of TNFR2 when compared with OA-FLS. TNFR2 expression in RA-FLS correlated with RA disease activity, synovial T- and B-cell infiltration. TNF and IL1β were identified as inflammatory mediators that upregulate TNFR2 in RA-FLS. Silencing of TNFR2 in RA-FLS markedly diminished the TNF-induced expression of inflammatory cytokines and chemokines, including CXCR3-binding chemokines and the B-cell activating factor TNFSF13B. Immunobiochemical analyses revealed that TNFR2-mediated expression of inflammatory mediators critically depends on STAT1. Conclusion Our results define a critical role for TNFR2 in FLS-driven inflammation and unfold its participation in the unresolved course of synovial inflammation in RA. [ABSTRACT FROM AUTHOR]

Objectives RA patients who fail to respond to MTX can receive biologic dMARDs (bDMARDs). The Torque Teno Virus (TTV) is a potential novel candidate for monitoring of immunosuppression. We explore TTV in these patients and its association with clinical response to bDMARDs. Methods The BioBio Study is a multicentre randomized open-label trial, including RA patients with insufficient response to MTX. Patients were randomized to either TNFi (infliximab, INF), anti-IL-6 (tocilizumab, TCZ), CTLA4-Ig (abatacept, ABA) or anti-CD20 (rituximab, RTX) in addition to MTX. PCR was used to quantify TTV in the peripheral blood. Results TTV was measured in 95 patients (INF, n  = 23; TCZ, n  = 22; ABA, n  = 27; RTX; n  = 23). TTV increased by a median of 4.5 × 104 copies/ml [c/ml; interquartile range (IQR) 0–7.5 × 105] after 3 months. TTV levels at month 3 were associated with the Simplified Disease Activity Index (SDAI) (P  = 0.03) and the Clinical Disease Activity Index (CDAI) response (P  = 0.026) at month 6. A TTV cut-off level of 1.2 × 106 c/ml at month 3 had a positive likelihood ratio of 2.7 for prediction of an 85% reduction in SDAI at month 6. Conclusion Our data suggest that TTV levels increase upon TNF, CD20 and costimulation blockade and are associated with the clinical response to bDMARDs in RA patients. Trial registration ClinicalTrials.gov; https://clinicaltrials.gov ; NCT01638715 [ABSTRACT FROM AUTHOR]

Abstract: In this era, it is axiomatic that cytokines have critical roles in cellular development and differentiation, immune homeostasis, and host defense. Equally, dysregulation of cytokines is known to contribute to diverse inflammatory and immune‐mediated disorders. In fact, the past 20 years have witnessed the rapid translation of basic discoveries in cytokine biology to multiple successful biological agents (mAbs and recombinant fusion proteins) that target cytokines. These targeted therapies have not only fundamentally changed the face of multiple immune‐mediated diseases but have also unequivocally established the role of specific cytokines in human disease; cytokine biologists have many times over provided remarkable basic advances with direct clinical benefit. Numerous cytokines rely on the JAK‐STAT pathway for signaling, and new, safe, and effective small molecule inhibitors have been developed for a range of disorders. In this review, we will briefly summarize basic discoveries in cytokine signaling and briefly comment on some major unresolved issues. We will review clinical data pertaining to the first generation of JAK inhibitors and their clinical indications, discuss additional opportunities for targeting this pathway, and lay out some of the challenges that lie ahead. [ABSTRACT FROM AUTHOR]

Objective. Abatacept (CTLA-4Ig) blocks CD28-mediated T cell activation by binding to the costimulatory B7 ligands CD80/CD86 on antigen presenting cells. Costimulatory molecules, however, can also be expressed on T cells upon activation. Therefore, the aim of our study was to investigate direct effects of CTLA-4Ig on distinct T cell subsets in RA patients. Methods. Phenotypic and functional analyses of CD4+ T cells, including CD4+FoxP3+CD25+ regulatory T cells (Treg), from RA patients were performed before and during CTLA-4Ig therapy. In addition T cells from healthy volunteers were analysed on in vitro culture with CTLA-4Ig or anti-CD80 and anti-CD86 antibodies. Apoptotic DNA fragmentation in CD4+ and CD4+FoxP3+ T cells was measured by TUNEL staining. Results. We observed an increase in T cells, including Treg cells, after initiation of CTLA-4Ig therapy, which was linked to a downregulation of activation-associated marker molecules and CD95 on CD4+ T cells and Treg cells. CTLA-4Ig decreased CD95-mediated cell death in vitro in a dose-dependent manner. Functional analysis of isolated Treg cells from RA patients further revealed a diminished suppression of responder T cell proliferation. This was found to be due to CTLA-4Ig-mediated blocking of CD80 and CD86 on responder T cells that led to a diminished susceptibility for Treg cell suppression. Conclusion. CTLA-4Ig therapy in RA patients exerts effects beyond the suppression of T cell activation, which has to be taken into account as an additional mechanism of CTLA-4Ig treatment. [ABSTRACT FROM AUTHOR]

Regulatory T cells (Treg) with the capacity to suppress T-cell proliferation exert various effects on T cell function. In addition, Treg have been shown to modulate the phenotype and function of antigen-presenting cells (APC) including dendritic cells (DC), B cells and monocytes/macrophages. However, the specific mechanism(s) of how Treg affect APC have not been entirely identified so far. In this study, we analyzed the interaction of human Treg and effector T cells (Teff) with peripheral blood myeloid and monocyte-derived dendritic cells in vitro. A strong tendency for cell cluster formation between Treg and DC was observed, which was dependent on the adhesion molecules ICAM-1, LFA-3 and ICAM-3. In addition, Treg were found to express higher levels of LFA-1, LFA-2, LFA-3 and ICAM-3 both before and after activation with anti-CD3 antibodies. Using in vitro live cell imaging, we were further able to show that Treg–DC cell clusters, in contrast to Teff–DC clusters, were stable and long lasting. Co-cultures of DC with Treg diminished the up-regulation of activation induced costimulatory molecule expression on DC, and further reduced the production of tumor necrosis factor alpha and stimulated the production of IL-4. In summary, our data indicate that Treg–DC cluster formation might enable Treg to modulate phenotypic and functional characteristics of DC and help to constrain Teff activation. [ABSTRACT FROM PUBLISHER]

The objective of the study was that the regulatory T cells (Treg) that specialize in the suppression of immune responses might be critically involved in the pathogenesis of autoimmune disease. As for systemic lupus erythematosus (SLE), however, published data concerning Treg phenotype and function are partly conflicting. We therefore performed quantitative and qualitative analyses of naturally occurring CD4+CD25+ Treg from SLE patients as compared with healthy controls (HC) in order to further elucidate the role of Treg in this systemic autoimmune disease. The phenotype of peripheral blood CD4+CD25+ Treg was determined by flow cytometry (FACS) in SLE patients and HC. Treg were isolated from SLE patients and HC and their functional capacity was analyzed in suppression assays. Phenotypic and functional data were correlated with clinical data. Decreased proportions of CD4+ Treg with high-level expression of CD25 (CD4+CD25hi) were observed in active and inactive SLE patients (0.96 ± 0.08 and 1.17 ± 0.08%, respectively) as compared with HC (2 ± 0.1%). In contrast to HC, Treg from SLE patients displayed an activated phenotype as determined by the expression of CD69, CD71 and HLA-DR. The suppressive capacity of isolated Treg from SLE patients, however, was significantly reduced as compared with HC. Proportions of CD4+CD25hi T cells and the suppressive capacity of Treg were inversely correlated with the clinical disease activity in SLE patients. Our data describe quantitative and qualitative defects of Treg in SLE patients. These deficiencies might contribute to the breakdown of self-tolerance and the development of the autoimmune response in SLE patients. [ABSTRACT FROM PUBLISHER]