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OBJECTIVE: To study the expression levels and immunostimulatory capacities of interleukin-7 (IL-7) in primary Sjögren's syndrome. METHODS: Labial salivary gland (LSG) IL-7 expression was determined by immunohistochemistry, using a quantitative scoring system, in 30 patients with sicca syndrome: 15 patients with primary Sjögren's syndrome (SS) and 15 patients with non-SS sicca syndrome. The correlation of IL-7 expression in LSGs with parameters of local and peripheral disease was studied, and serum and salivary IL-7 levels were determined. Additionally, the effects of IL-7 on cytokine production by peripheral blood mononuclear cells (PBMCs) from patients with primary SS were determined in vitro by Luminex multicytokine assay and compared with the effects in control subjects. RESULTS: The expression of IL-7 in LSGs was higher in patients with primary SS compared with that in patients with non-SS sicca syndrome. IL-7 was observed primarily in the vicinity of lymphocytic infiltrates. Salivary IL-7 levels in patients with primary SS were higher than those in control subjects. In all 30 patients with sicca syndrome, IL-7 expression in LSGs correlated with parameters of both local and peripheral disease. Furthermore, IL-7 stimulated T cell-attracting and T cell-differentiating cytokines (monokine induced by interferon-gamma [IFNgamma], IFNgamma-inducible 10-kd protein, IL-12, and IL-15), as well as Th1 (IFNgamma), Th2 (IL-4), Th17 (IL-17A), proinflammatory (tumor necrosis factor alpha and IL-1alpha), and regulatory (IL-10 and IL-13) cytokine production by PBMCs. All of these cytokines were previously shown to be associated with primary SS. The IL-7-induced increase in IL-10 production in patients with primary SS was reduced compared with that in control subjects. CONCLUSION: The correlation between LSG IL-7 expression and (local) disease parameters in primary SS as well as the IL-7-mediated induction of inflammatory cytokines indicate that IL-7 might contribute to the immunopathology of primary SS. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To evaluate the expression and functional ability of the high-affinity interleukin-7 receptor (IL-7Ralpha) in patients with rheumatoid arthritis (RA). METHODS: Expression of IL-7Ralpha and IL-7 was determined in synovial tissue from RA patients and was compared with that in synovial tissue from patients with undifferentiated arthritis (UA) and osteoarthritis (OA). IL-7Ralpha expression on CD4 T cells, CD19 B cells, and CD14 monocyte/macrophages from RA synovial tissue, synovial fluid, and peripheral blood was also assessed. The proliferative capacity of IL-7Ralpha(bright) and IL-7Ralpha(dim/-) T cells was measured. In addition, we examined IL-7R blockade with soluble human IL-7Ralpha (hIL-7Ralpha) in the prevention of immune activation of peripheral blood mononuclear cells. RESULTS: We found significantly higher IL-7Ralpha expression in RA and UA synovial tissue than in OA synovial tissue, and the level of IL-7Ralpha expression correlated significantly with the levels of CD3 and IL-7 expression. CD4 T cells from RA synovial fluid and synovial tissue strongly expressed IL-7Ralpha. A substantial percentage of B cells and macrophages from RA synovial fluid and synovial tissue also expressed IL-7Ralpha, although less prominently than T cells. We found that peripheral blood IL-7Ralpha(bright) T cells that did not express FoxP3 were highly proliferative as compared with IL-7Ralpha(dim/-) T cells that did express high levels of FoxP3. Soluble hIL-7Ralpha inhibited IL-7-induced proliferation and interferon-gamma production by mononuclear cells from RA patients. CONCLUSION: Our data suggest that enhanced expression of IL-7Ralpha and IL-7 in RA patients contributes significantly to the joint inflammation by activating T cells, B cells, and macrophages. The inhibition of IL-7R-mediated immune activation by soluble hIL-7Ralpha further indicates an important role of IL-7Ralpha in inflammatory responses in RA, suggesting IL-7Ralpha as a therapeutic target for immunotherapy in RA. [ABSTRACT FROM AUTHOR]

Objectives: To assess to what extent leflunomide (LEF) and hydroxychloroquine (HCQ) therapy in patients with primary Sjögren's syndrome (RepurpSS-I) targets type I IFN-associated responses and to study the potential of several interferon associated RNA-based and protein-based biomarkers to predict and monitor treatment., Methods: In 21 patients treated with LEF/HCQ and 8 patients treated with placebo, blood was drawn at baseline, 8, 16 and 24 weeks. IFN-signatures based on RNA expression of five IFN-associated genes were quantified in circulating mononuclear cells and in whole blood. MxA protein levels were measured in whole blood, and protein levels of CXCL10 and Galectin-9 were quantified in serum. Differences between responders and non-responders were assessed and receiver operating characteristic analysis was used to determine the capacity of baseline expression and early changes (after 8 weeks of treatment) in biomarkers to predict treatment response at the clinical endpoint., Results: IFN-signatures in peripheral blood mononuclear cell and whole blood decreased after 24 weeks of LEF/HCQ treatment, however, changes in IFN signatures only poorly correlated with changes in disease activity. In contrast to baseline IFN signatures, baseline protein concentrations of galectin-9 and decreases in circulating MxA and Galectin-9 were robustly associated with clinical response. Early changes in serum Galectin-9 best predicted clinical response at 24 weeks (area under the curve 0.90)., Conclusions: LEF/HCQ combination therapy targets type-I IFN-associated proteins that are associated with strongly decreased B cell hyperactivity and disease activity. IFN-associated Galectin-9 is a promising biomarker for treatment prediction and monitoring in pSS patients treated with LEF/HCQ., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Type 2 conventional dendritic cells (cDC2s) are key orchestrators of inflammatory responses, linking innate and adaptative immunity. Here we explored the regulation of immunological pathways in cDC2s from patients with primary Sjögren's syndrome (pSS)., Methods: RNA sequencing of circulating cDC2s from patients with pSS, patients with non-Sjögren's sicca and healthy controls (HCs) was exploited to establish transcriptional signatures. Phenotypical and functional validation was performed in independent cohorts., Results: Transcriptome of cDC2s from patients with pSS revealed alterations in type I interferon (IFN), toll-like receptor (TLR), antigen processing and presentation pathways. Phenotypical validation showed increased CX3CR1 expression and decreased integrin beta-2 and plexin-B2 on pSS cDC2s. Functional validation confirmed impaired capacity of pSS cDC2s to degrade antigens and increased antigen uptake, including self-antigens derived from salivary gland epithelial cells. These changes in antigen uptake and degradation were linked to anti-SSA/Ro (SSA) autoantibodies and the presence of type I IFNs. In line with this, in vitro IFN-α priming enhanced the uptake of antigens by HC cDC2s, reflecting the pSS cDC2 profile. Finally, pSS cDC2s compared with HC cDC2s increased the proliferation and the expression of CXCR3 and CXCR5 on proliferating CD4 + T cells., Conclusions: pSS cDC2s are transcriptionally altered, and the aberrant antigen uptake and processing, including (auto-)antigens, together with increased proliferation of tissue-homing CD4 + T cells, suggest altered antigen presentation by pSS cDC2s. These functional alterations were strongly linked to anti-SSA positivity and the presence of type I IFNs. Thus, we demonstrate novel molecular and functional pieces of evidence for the role of cDC2s in orchestrating immune response in pSS, which may yield novel avenues for treatment., Competing Interests: Competing interests: TRDJR was the principal investigator in the immune catalyst programme of GlaxoSmithKline, which was an independent research programme. He did not receive any financial support other than the research funding for the current project. Currently, He is an employee of Abbvie, where he holds stock. He had no part in the design and interpretation of the study results after he started at Abbvie.The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To develop a composite responder index in primary Sjögren's syndrome (pSS): the Sjögren's Tool for Assessing Response (STAR)., Methods: To develop STAR, the NECESSITY (New clinical endpoints in primary Sjögren's syndrome: an interventional trial based on stratifying patients) consortium used data-driven methods based on nine randomised controlled trials (RCTs) and consensus techniques involving 78 experts and 20 patients. Based on reanalysis of rituximab trials and the literature, the Delphi panel identified a core set of domains with their respective outcome measures. STAR options combining these domains were proposed to the panel for selection and improvement. For each STAR option, sensitivity to change was estimated by the C-index in nine RCTs. Delphi rounds were run for selecting STAR. For the options remaining before the final vote, a meta-analysis of the RCTs was performed., Results: The Delphi panel identified five core domains (systemic activity, patient symptoms, lachrymal gland function, salivary gland function and biological parameters), and 227 STAR options combining these domains were selected to be tested for sensitivity to change. After two Delphi rounds, a meta-analysis of the 20 remaining options was performed. The candidate STAR was then selected by a final vote based on metrological properties and clinical relevance., Conclusion: The candidate STAR is a composite responder index that includes all main disease features in a single tool and is designed for use as a primary endpoint in pSS RCTs. The rigorous and consensual development process ensures its face and content validity. The candidate STAR showed good sensitivity to change and will be prospectively validated by the NECESSITY consortium in a dedicated RCT., Competing Interests: Competing interests: RS has received consulting fees from GlaxoSmithKline, Boehringer, Janssen and Novartis, participated in an advisory board for Janssen, and received support for attending meeting from GlaxoSmithKline and Amgen. DC has received consulting fees from GlaxoSmithKline, Bristol Myers Squibb, Janssen, Amgen, Pfizer and Roche. J-EG has received honoraria from AbbVie, Bristol Myers Squibb, Eli Lilly, Galapagos, Gilead, Pfizer, Roche, Sanofi, Novartis, MSD, CSL Behring and Genzyme and received grant from Bristol Myers Squibb. SJB and BF receive funding from the National Institute for Health Research (NIHR) Birmingham Biomedical Research Centre, Birmingham, UK. SJB has provided consultancy services in the field of clinical trial design for Sjögren’s syndrome for AbbVie, AstraZeneca, Galapagos and Novartis Pharmaceuticals in 2018–2021. BF has received grants from Servier, Galapagos and Janssen, provided consultancy services for Novartis, Bristol Myers Squibb, Janssen and Servier, and received honoraria from Bristol Myers Squibb and Novartis. MB has received grants from Amgen/MedImmune, Janssen and GlaxoSmithKline, and personal fees from UCB, Amgen/MedImmune, Janssen and GlaxoSmithKline. HB has received grants from Bristol Myers Squibb and Roche, and consulting fees from Bristol Myers Squibb, Roche, Novartis, MedImmune and Union Chimique Belge. WH and PG are employees of Novartis Pharma and recipients of Novartis stocks. XM has received a grant from Ose Pharmaceuticals and consultancy fees from Bristol Myers Squibb, Galapagos, GlaxoSmithKline, Janssen, Novartis, Pfizer and UCB. GB, MC, EP, JAvR, VD-P and RP declare no competing interests., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Objectives: Systemic sclerosis (SSc) is an autoimmune disease with unknown pathogenesis manifested by inflammation, vasculopathy and fibrosis in skin and internal organs. Type I interferon signature found in SSc propelled us to study plasmacytoid dendritic cells (pDCs) in this disease. We aimed to identify candidate pathways underlying pDC aberrancies in SSc and to validate its function on pDC biology., Methods: In total, 1193 patients with SSc were compared with 1387 healthy donors and 8 patients with localised scleroderma. PCR-based transcription factor profiling and methylation status analyses, single nucleotide polymorphism genotyping by sequencing and flow cytometry analysis were performed in pDCs isolated from the circulation of healthy controls or patients with SSc. pDCs were also cultured under hypoxia, inhibitors of methylation and hypoxia-inducible factors and runt-related transcription factor 3 (RUNX3) levels were determined. To study Runx3 function, Itgax -Cre: Runx3 f/f mice were used in in vitro functional assay and bleomycin-induced SSc skin inflammation and fibrosis model., Results: Here, we show downregulation of transcription factor RUNX3 in SSc pDCs. A higher methylation status of the RUNX3 gene, which is associated with polymorphism rs6672420, correlates with lower RUNX3 expression and SSc susceptibility. Hypoxia is another factor that decreases RUNX3 level in pDC. Mouse pDCs deficient of Runx3 show enhanced maturation markers on CpG stimulation. In vivo, deletion of Runx3 in dendritic cell leads to spontaneous induction of skin fibrosis in untreated mice and increased severity of bleomycin-induced skin fibrosis., Conclusions: We show at least two pathways potentially causing low RUNX3 level in SSc pDCs, and we demonstrate the detrimental effect of loss of Runx3 in SSc model further underscoring the role of pDCs in this disease., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective : Effective treatment for primary Sjögren's syndrome (pSS) is not available. pSS immunopathology involves a variety of immune-cells and dysregulated pathways; targeting several pathways instead of only one could therefore be effective. Treatment with leflunomide (LEF) and hydroxychloroquine (HCQ) might be successful given their unique immunosuppressive properties. We aimed to study the in vitro effects of LEF, HCQ and their combination on T- and B-cell proliferation, cytokine and immunoglobulin production by activated PBMCs. Methods : PBMCs of six healthy individuals and nine pSS patients were stimulated with superantigen and TLR9 agonist to mimic the hallmark features. LEF, HCQ and their combinations were tested at clinically observed concentrations and proliferation, cytokine and immunoglobulin production were measured. Results : TCR/TLR9 activation of PBMCs induced strong proliferation of T and B-cells and production of CXCL13, IFN-α, IFN-γ, IgG and IgM. LEF dose-dependently inhibited all measured parameters, where HCQ potently and dose-dependently decreased B cell proliferation, CXCL13, IFN-α, IgG and IgM production. At different concentration combinations, HCQ and LEF inhibited several immune hallmark features more potently than each single compound. Conclusion : A combination of LEF and HCQ at clinically applicable concentrations additively inhibits immune activation, supporting a potential implementation of this drug combination in pSS treatment.

Unlabelled: Chronic pain is a major clinical problem that is difficult to treat and requires novel therapies. Although most pain therapies primarily target neurons, neuroinflammatory processes characterized by spinal cord and dorsal root ganglion production of proinflammatory cytokines play an important role in persistent pain states and represent potential therapeutic targets. Anti-inflammatory cytokines are attractive candidates to regulate aberrant neuroinflammatory processes, but the therapeutic potential of these cytokines as stand-alone drugs is limited. Their optimal function requires concerted actions with other regulatory cytokines, and their relatively small size causes rapid clearance. To overcome these limitations, we developed a fusion protein of the anti-inflammatory cytokines interleukin 4 (IL4) and IL10. The IL4-10 fusion protein is a 70 kDa glycosylated dimeric protein that retains the functional activity of both cytokine moieties. Intrathecal administration of IL4-10 dose-dependently inhibited persistent inflammatory pain in mice: three IL4-10 injections induced full resolution of inflammatory pain in two different mouse models of persistent inflammatory pain. Both cytokine moieties were required for optimal effects. The IL4-10 fusion protein was more effective than the individual cytokines or IL4 plus IL10 combination therapy and also inhibited allodynia in a mouse model of neuropathic pain. Mechanistically, IL4-10 inhibited the activity of glial cells and reduced spinal cord and dorsal root ganglion cytokine levels without affecting paw inflammation. In conclusion, we developed a novel fusion protein with improved efficacy to treat pain, compared with wild-type anti-inflammatory cytokines. The IL4-10 fusion protein has potential as a treatment for persistent inflammatory pain., Significance Statement: The treatment of chronic pain is a major clinical and societal challenge. Current therapies to treat persistent pain states are limited and often cause major side effects. Therefore, novel analgesic treatments are urgently needed. In search of a novel drug to treat chronic pain, we developed a fusion protein consisting of two prototypic regulatory cytokines, interleukin 4 (IL4) and IL10. The work presented in this manuscript shows that this IL4-10 fusion protein overcomes some major therapeutic limitations of pain treatment with individual cytokines. The IL4-10 fusion protein induces full resolution of persistent inflammatory pain in two different mouse models. These novel findings are significant, as they highlight the IL4-10 fusion protein as a long-needed potential new drug to stop persistent pain states., (Copyright © 2016 the authors 0270-6474/16/367353-11$15.00/0.)

Objective: Indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme that converts tryptophan to kynurenine, is driven in part by type I and type II interferons (IFNs). Naive T cells are polarized into FoxP3+ Treg cells upon exposure to either IDO+ cells or kynurenine. Recent studies have suggested that the kynurenine pathway reflects a crucial interface between the immune and nervous system. The aims of the present study were to evaluate whether Treg cell levels are elevated, in conjunction with increased IDO activity, in patients with primary Sjögren's syndrome (SS) who are positive for the IFN gene expression signature, and to investigate the downstream kynurenine pathway in these patients., Methods: Serum from 71 healthy controls, 58 IFN-negative patients with primary SS, and 66 IFN-positive patients with primary SS was analyzed using high-performance liquid chromatography to measure the levels of tryptophan and kynurenine. Expression levels of messenger RNA (mRNA) for IDO and downstream enzymes in the kynurenine pathway were assessed in CD14+ monocytes using real-time quantitative polymerase chain reaction. CD4+CD45RO+ T helper memory cell populations were analyzed by flow cytometry., Results: Significantly increased levels of IDO activity (assessed as the kynurenine:tryptophan ratio) (P = 0.0054) and percentages of CD25(high) FoxP3+ Treg cells (P = 0.039) were observed in the serum from IFN-positive patients with primary SS, and these parameters were significantly correlated with one another (r = 0.511, P = 0.002). In circulating monocytes from IFN-positive patients with primary SS, the expression of IDO1 mRNA was up-regulated (P < 0.0001), and this was correlated with the IFN gene expression score (r = 0.816, P < 0.0001). Interestingly, the proapoptotic and neurotoxic downstream enzyme kynurenine 3-monooxygenase was up-regulated (P = 0.0057), whereas kynurenine aminotransferase I (KATI) (P = 0.0003), KATIII (P = 0.016), and KATIV (P = 0.04) were down-regulated in IFN-positive patients with primary SS compared to healthy controls., Conclusion: These findings demonstrate enhanced IDO activity in conjunction with increased percentages of CD25(high) FoxP3+ Treg cells in primary SS patients who carry the IFN signature. In addition, IFN-positive patients with primary SS exhibit an imbalanced kynurenine pathway, with evidence of a shift toward potentially more proapoptotic and neurotoxic metabolites. Intervening in these IFN- and IDO-induced immune system imbalances may offer a new array of possibilities for therapeutic interventions in patients with primary SS., (© 2016, American College of Rheumatology.)

The antiphospholipid syndrome (APS) is a systemic autoimmune disease that is characterized serologically by the presence of antiphospholipid antibodies (aPL) and clinically by vascular thrombosis and obstetric complications. The protein β2 glycoprotein I (β2GPI) is identified as the most important autoantigen in this syndrome. Activation of endothelial cells, thrombocytes and placental tissue by anti-β2GPI antibodies relates to the clinical manifestations of APS. This review describes genetic and environmental factors in relation to APS and summarizes the current knowledge on abnormalities in components of both the innate and adaptive immune system in APS. The role of dendritic cells, T-cells, B-cells, monocytes, neutrophils and NK-cells as well as the complement system in APS are discussed. Several gaps in our knowledge on the pathophysiology of APS are identified and a plea is made for future extensive immune cell profiling by a systems medicine approach in order to better unravel the pathogenesis of APS, to gain more insight in the role of the immune system in APS as well as having the potential to reveal biomarkers or novel therapeutic targets., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Objectives: Thymic Stromal Lymphopoietin (TSLP) is a potent immunomodulatory cytokine involved in Th2- and Th17-mediated immune responses in different autoimmune diseases. TSLP expression in relation to disease activity was studied in salivary glands of primary Sjögren's syndrome (pSS) patients as compared to non-SS sicca (nSS) controls., Methods: Tissue sections of minor salivary glands from pSS and nSS patients were stained with monoclonal antibodies against human TSLP, CD3, CD19 and cytokeratin high molecular weight (CK HMW) or stained for Alcian blue to detect mucus production. The number of TSLP-expressing cells was quantified and expression was correlated to local and systemic disease parameters., Results: The number of TSLP-expressing cells was significantly lower in pSS patients than in nSS controls and correlated with a range of disease markers. In pSS patients, TSLP was expressed outside of lymphocytic infiltrates at sections that also encompassed high numbers of intact acinar cells. This difference was independent of tissue destruction., Conclusions: Reduced TSLP expression in pSS patients is associated with increased local and systemic inflammatory markers. Loss of TSLP expression may contribute to Th1/Th17-associated immunopathology in pSS, in line with previous studies demonstrating that TSLP promotes a protective Th2 milieu at mucosal sites.

Objective: Innate lymphoid cells (ILCs) are a recently discovered group of cells that are essential to epithelial homeostasis and are implicated in psoriasis pathogenesis, yet they have never been reported in psoriatic arthritis (PsA)., Methods: ILC classes and subsets were characterized in the peripheral blood (PB) of healthy controls, patients with psoriasis, and patients with PsA and in the synovial fluid (SF) of patients with PsA and patients with rheumatoid arthritis (RA). Cell surface marker expression and intracellular cytokine production following stimulation were analyzed using flow cytometry., Results: ILCs were identified in the SF and were 4-fold more abundant in PsA SF than in PsA PB. Fewer CCR6+ ILCs were found in PsA PB than in healthy control PB, while PsA SF was enriched for CCR6+ ILCs compared to PsA PB and RA SF. Natural cytotoxicity receptor NKp44+ group 3 ILCs were rare in PB and RA SF, but abundant in PsA SF. Increased numbers of interleukin-17A (IL-17A)-producing ILCs were present in PsA SF compared to RA SF. CCR6, NKp44, and melanoma cell adhesion molecule (MCAM) were expressed on the cell surface of SF ILCs that produced IL-17A. The number of circulating NKp44+, CCR6+, and MCAM+ ILCs in blood was inversely correlated with PsA disease activity., Conclusion: Our findings indicate that PsA SF is enriched for group 3 ILCs that express CCR6 and NKp44, which distinguishes the synovial compartment from RA. The increased IL-17A production by SF ILCs indicates a novel role for ILCs in PsA., (© 2015, American College of Rheumatology.)

Thymic stromal lymphopoietin (TSLP) is an IL-7-related cytokine that has been studied extensively in atopic diseases and more recently in various rheumatic disorders. It is involved in T cell development in the thymus and promotes homeostatic T cell expansion by classical dendritic cells. However, deregulated TSLP expression in various rheumatic diseases has implicated this cytokine as a strong mediator in immunopathology. Overexpressed TSLP induces strong T cell activation and production of pro-inflammatory cytokines in human cells and animal models for RA, SSc and LN, underscoring the therapeutic potential of targeting the TSLP-TSLP receptor axis., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Introduction: The cytokines interleukin (IL)-7 and thymic stromal lymphopoietin (TSLP) signal through the IL-7R subunit and play proinflammatory roles in experimental arthritis and rheumatoid arthritis (RA). We evaluated the effect of inhibition of IL-7R- and TSLPR-signalling as well as simultaneous inhibition of IL-7R- and TSLPR-signalling in murine experimental arthritis. In addition, the effects of IL-7 and TSLP in human RA dendritic cell (DC)/T-cell co-cultures were studied., Methods: Arthritis was induced with proteoglycan in wildtype mice (WT) and in mice deficient for the TSLP receptor subunit (TSLPR-/-). Both mice genotypes were treated with anti-IL-7R or phosphate buffered saline. Arthritis severity was assessed and local and circulating cytokines were measured. Autologous CD1c-positive DCs and CD4 T-cells were isolated from peripheral blood of RA patients and were co-cultured in the presence of IL-7, TSLP or both and proliferation and cytokine production were assessed., Results: Arthritis severity and immunopathology were decreased in WT mice treated with anti-IL-7R, in TSLPR-/- mice, and the most robustly in TSLPR-/- mice treated with anti-IL-7R. This was associated with strongly decreased levels of IL-17, IL-6 and CD40L. In human DC/T-cell co-cultures, TSLP and IL-7 additively increased T-cell proliferation and production of Th17-associated cytokines, chemokines and tissue destruction factors., Conclusion: TSLP and IL-7 have an additive effect on the production of Th17-cytokines in a human in vitro model, and enhance arthritis in mice linked with enhanced inflammation and immunopathology. As both cytokines signal via the IL-7R, these data urge for IL-7R-targeting to prevent the activity of both cytokines in RA.

Objective: To investigate whether the potential of abatacept to inhibit vigorous CD1c myeloid dendritic cell (MDC)-driven activation of naive and memory CD4 T cells is abrogated in the presence of T cell-activating cytokines., Methods: CD4 T cell subsets (naive [Tn], central memory [Tcm], and effector memory [Tem] T cells) were isolated from the peripheral blood (PB) of healthy controls and the PB and synovial fluid (SF) of rheumatoid arthritis (RA) patients. CD4 T cells were cocultured with autologous, thymic stromal lymphopoietin (TSLP)-primed CD1c MDCs in the presence or absence of abatacept (CTLA-4Ig) and/or interleukin-7 (IL-7) or IL-15. Subsequently, T cell proliferation and cytokine production were measured., Results: The percentages of each CD4 T cell subset from the circulation of healthy controls and RA patients were comparable and mainly consisted of Tn and Tcm cells, whereas the SF of RA patients mainly consisted of Tcm and Tem cells. Activation of CD4 T cell subsets by TSLP-primed MDCs from the RA PB was completely blocked by abatacept. Addition of IL-7 or IL-15 to the cocultures strongly increased CD4 T cell activation and overruled the inhibitory capacity of abatacept. IL-7-induced reversal was associated with robust induction of interferon-γ, tumor necrosis factor α, and IL-17 secretion. Similarly, CD4 T cell proliferation induced by TSLP-primed MDCs from the SF of RA patients was strongly blocked by abatacept, but this inhibitory effect was vigorously overruled in the presence of IL-7., Conclusion: These findings indicate that the presence of T cell-activating cytokines such as IL-7 or IL-15 in the joints of RA patients reduces the capacity of abatacept to inhibit MDC-driven CD4 T cell activation. This mechanism may be one explanation for the partial, and sometimes absent, response to abatacept therapy in a subset of patients., (Copyright © 2015 by the American College of Rheumatology.)

The lifespan of humans has increased drastically over the last decades; considerable effort has been applied to delineate the mechanisms behind aging in order to find strategies for longevity. As the benefits of the gained knowledge might extend to diseases, where accelerated aging is suspected, the role of aging in the systemic autoimmune disease Systemic Lupus Erythematosus (SLE) is of particular interest. In this review the immunological similarities of SLE and aging are analyzed on three levels: the clinical, the cellular and the molecular, in order to find possible common pathological mechanisms. Common clinical features (e.g. increased infection rates, incidence of tumors and cardiovascular diseases) of SLE-patients and elderly individuals and shared characteristics of immuno-senescence and SLE are identified. These similarities are strongest in the adaptive immune system, where terminally differentiated T-cells and an immunological risk profile are found in both conditions. Also the aging innate immune system has overlapping features with SLE, exemplified by a generally lowered phagocytic capacity. However, great disparities between the aging immune system and SLE become apparent on a closer look, affecting numbers, phenotype and function of most immune cells, ranging from NETosis by granulocytes to the mechanisms underlying abnormal IL-2 production by T-cells. On the molecular level, also the increased presence of aging mechanisms like telomere attrition, DNA damage, autophagy and the characteristics of the mTOR pathway in SLE, possibly contributing to the shared changes on the cellular and clinical level are elaborated. The possible implications thereof concern existing (hydroxychloroquine, rapamycine, Glucocorticoids) as well as novel therapeutic strategies targeting more specific pathways which might rapidly reach the clinical arena. Overall a differential view on the similarities of aging and SLE and possible consequences is presented.

Introduction: The aim of this study was to investigate PD-1/PD-L1 involvement in the hyporesponsiveness of rheumatoid arthritis (RA) synovial fluid (SF) CD4 T cells upon stimulation by thymic stromal lymphopoietin (TSLP)-primed CD1c myeloid dendritic cells (mDCs)., Methods: Expression of PD-1 on naïve (Tn), central memory (Tcm) and effector memory (Tem) CD4 T cell subsets was assessed by flow cytometry. PD-L1 expression and its regulation upon TSLP stimulation of mDCs from peripheral blood (PB) and SF of RA patients were investigated by quantitative RT-PCR and flow cytometry. The involvement of PD-1/PD-L1 interactions in SF T cell hyporesponsiveness upon (TSLP-primed) mDC activation was determined by cell culture in the presence of PD-1 blocking antibodies, with or without interleukin 7 (IL-7) as a recognized suppressor of PD-1 expression., Results: PD-1 expression was increased on CD4 T cells derived from SF compared with PB of RA patients. TSLP increased PD-L1 mRNA expression in both PB and SF mDCs. PD-L1 protein expression was increased on SF mDCs compared with PB mDCs and was associated with T cell hyporesponsiveness. Blockade of PD-1, as well as IL-7 stimulation, during cocultures of memory T cells and (TSLP-primed) mDCs from RA patients significantly recovered T cell proliferation., Conclusion: SF T cell hyporesponsiveness upon (TSLP-primed) mDC stimulation in RA joints is partially dependent on PD-1/PD-L1 interactions, as PD-1 and PD-L1 are both highly expressed on SF T cells and mDCs, respectively, and inhibiting PD-1 availability restores T cell proliferation. The potential of IL-7 to robustly reverse this hyporesponsiveness suggests that such proinflammatory cytokines in RA joints strongly contribute to memory T cell activation.

Objectives: To investigate the prognostic value of the lymphocytic focus score (LFS) and the percentages of IgA+, IgM+ and IgG+ plasma cells for disease severity of primary Sjögren syndrome (pSS)., Methods: Medical charts of 174 pSS patients were retrospectively analysed, comparing histology results (LFS and percentages of IgA+, IgM+ and IgG+ plasma cells) with disease outcomes as non-Hodgkin lymphoma (NHL) and clinical scores including cumulative EULAR (European League against Rheumatism) Sjögren syndrome disease activity index (ESSDAI) and the total number of extraglandular manifestations., Results: The mean LFS was significantly higher in patients developing NHL (3.0±0.894 vs 2.25±1.086; p=0.021). The threshold of ≥3 foci has a positive predictive value of 16% for lymphoma, and a negative predictive value of 98%. Only LFS ≥3 contributed significantly and independently to NHL development in a standard multiple regression model. Ig class distribution of plasma cells did not help to identify patients developing lymphoma. Patients with LFS ≥3, ≤40% IgA+ or ≥25% IgM+ plasma cells in salivary gland biopsy specimens had significantly enhanced systemic disease., Conclusions: Routine histopathological minor salivary gland assessment has important prognostic value. The LFS might help to identify patients with an increased risk for lymphoma., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Objective: To determine the levels of thymic stromal lymphopoietin (TSLP) and the numbers of TSLP receptor (TSLPR)-expressing CD1c+ (blood dendritic cell antigen 1-positive) myeloid dendritic cells (MDCs) in the joints as compared with the peripheral blood (PB) of patients with rheumatoid arthritis (RA), as well as to determine the capacity of TSLP to induce MDC-dependent T cell activation., Methods: TSLP levels were measured in synovial fluid (SF) samples from patients with RA and those with osteoarthritis (OA). MDC numbers in PB and SF samples from RA patients and TSLPR expression on these cells were assessed by fluorescence-activated cell sorter analysis. PB and SF MDCs from RA patients were stimulated with TSLP, and cytokine production was measured by multiplex immunoassay. TSLP-primed MDCs were cocultured with autologous CD4+ T cells in the absence of additional stimuli, and subsequently, cell proliferation and cytokine production were measured., Results: TSLP levels were significantly increased in SF samples from RA versus OA patients. The numbers of TSLPR-expressing MDCs in the SF of RA patients were significantly increased as compared to those in the PB, and SF MDCs displayed increased levels of TSLPR. TSLP selectively stimulated the production of thymus and activation-regulated chemokine and macrophage inflammatory protein 1α by CD1c+ MDCs. TSLP-primed MDCs from PB and SF potently stimulated the proliferation of autologous CD4+ T cells as compared to unstimulated MDCs. Enhanced proliferation was associated with increased production of interferon-γ, interleukin-17 (IL-17), and IL-4., Conclusion: These data support an inflammatory mechanism by which increased intraarticular TSLP in RA potently activates TSLPR-expressing CD1c+ MDCs in the joints to secrete chemokines, causing chemotaxis and subsequent activation of CD4+ T cells. In addition to the demonstrated inflammatory potential of TSLP in experimental arthritis, this suggests that TSLP and TSLPR-expressing MDCs could both play a pivotal role in the immunopathology of RA., (Copyright © 2014 by the American College of Rheumatology.)

Objectives: To investigate the potential synergy of IL-7-driven T cell-dependent and TLR7-mediated B cell activation and to assess the additive effects of monocyte/macrophages in this respect., Methods: Isolated CD19 B cells and CD4 T cells from healthy donors were co-cultured with TLR7 agonist (TLR7A, Gardiquimod), IL-7, or their combination with or without CD14 monocytes/macrophages (T/B/mono; 1 : 1 : 0,1). Proliferation was measured using 3H-thymidine incorporation and Ki67 expression. Activation marker (CD19, HLA-DR, CD25) expression was measured by FACS analysis. Immunoglobulins were measured by ELISA and release of cytokines was measured by Luminex assay., Results: TLR7-induced B cell activation was not associated with T cell activation. IL-7-induced T cell activation alone and together with TLR7A synergistically increased numbers of both proliferating (Ki67+) B cells and T cells, which was further increased in the presence of monocytes/macrophages. This was associated by up regulation of activation markers on B cells and T cells. Additive or synergistic induction of production of immunoglobulins by TLR7 and IL-7 was associated by synergistic induction of T cell cytokines (IFNγ, IL-17A, IL-22), which was only evident in the presence of monocytes/macrophages., Conclusions: IL-7-induced CD4 T cell activation and TLR7-induced B cell activation synergistically induce T helper cell cytokine and B cell immunoglobulin production, which is critically dependent on monocytes/macrophages. Our results indicate that previously described increased expression of IL-7 and TLR7 together with increased numbers of macrophages at sites of inflammation in autoimmune diseases like RA and pSS significantly contributes to enhanced lymphocyte activation.

In recent years considerable progress has been made in our understanding of the immunopathology of primary Sjögren's syndrome. Several genetic and environmental risk factors as well as cellular and molecular pathways have been identified, providing multiple targets for therapeutic strategies. Establishment of disease activity scores allows careful monitoring of therapeutic strategies and has set the stage for definition of clinical response criteria. Early detection of autoimmune symptoms before the onset of primary Sjögren's syndrome might trigger early intervention strategies to prevent immunopathology. New studies that indicated a strong association between lymphoid neogenesis and development of lymphoma and extra-glandular manifestations indicate that future therapeutic strategies should perhaps be directed at patients at risk for more severe disease. Several challenges remain, such as dissecting the causes and consequences of several types of IFN signatures or elucidating how viral triggering of the immune system is involved and could be targeted. The biggest challenge may be prevention of dryness since the causes of dryness remain elusive and could include non-immunological ones. In the coming years it will become clear to what extent novel drugs can prevent immunopathology and clinical symptoms like dryness and fatigue.

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease that is characterized by mononuclear cell infiltration of exocrine glands. T-cells have been shown to play a central role in tissue destruction and regulation of B-cell activity and the production of autoantibodies typifying pSS. Despite the fact that dendritic cells (DCs) are candidate key players in the activation of T- and B-cells in pSS, their contribution has been under evaluated. This manuscript reviews current insights in DC biology and examines literature on the role of DCs in the immunopathology of primary Sjögren's syndrome, focusing on the interplay between dendritic cells, epithelial cells and T-cells.

Inflammatory fibrotic disorders have been of high interest both for dermatologists and rheumatologists. Although the phenotypic end stage of this group of diseases is ultimately the same, namely fibrosis, patients present with different clinical features and are often treated with distinct therapeutic modalities. This review addresses whether there is evidence for different underlying molecular pathways in the various inflammatory fibrotic diseases such as localized scleroderma, pediatric lichen sclerosus, adult lichen sclerosus, eosinophilic fasciitis and systemic sclerosis. To investigate this, a large number of gene expression microarray studies performed on skin or fibroblasts from patients with these aforementioned diseases were described, (re-)analysed, and compared. As suspected by the heterogeneous phenotype, most diseases showed unique gene expression features. Intriguingly, a clear overlap was observed between adult and pediatric lichen sclerosus and localized scleroderma, in antigen processing and the interferon pathway. Delineating the cause and consequence of these pathways may generate novel tools to better characterize and more effectively treat these patients.

Introduction: Myeloid dendritic cells (mDCs) are potent T cell-activating antigen-presenting cells that have been suggested to play a crucial role in the regulation of immune responses in many disease states, including rheumatoid arthritis (RA). Despite this, studies that have reported on the capacity of naturally occurring circulating mDCs to regulate T cell activation in RA are still lacking. This study aimed to evaluate the phenotypic and functional properties of naturally occurring CD1c (BDCA-1)+ mDCs from synovial fluid (SF) compared to those from peripheral blood (PB) of RA patients., Methods: CD1c+ mDC numbers and expression of costimulatory molecules were assessed by fluorescence-activated cell sorting (FACS) analysis in SF and PB from RA patients. Ex vivo secretion of 45 inflammatory mediators by mDCs from SF and PB of RA patients was determined by multiplex immunoassay. The capacity of mDCs from SF to activate autologous CD4+ T cells was measured., Results: CD1c+ mDC numbers were significantly increased in SF versus PB of RA patients (mean 4.7% vs. 0.6%). mDCs from SF showed increased expression of antigen-presenting (human leukocyte antigen (HLA) class II, CD1c) and costimulatory molecules (CD80, CD86 and CD40). Numerous cytokines were equally abundantly produced by mDCs from both PB and SF (including IL-12, IL-23, IL-13, IL-21). SF mDCs secreted higher levels of interferon γ-inducible protein-10 (IP-10), monokine induced by interferon γ (MIG) and, thymus and activation-regulated chemokine (TARC), but lower macrophage-derived chemokine (MDC) levels compared to mDCs from PB. mDCs from SF displayed a strongly increased capacity to induce proliferation of CD4+ T cells associated with a strongly augmented IFNγ, IL-17, and IL-4 production., Conclusions: This study suggests that increased numbers of CD1c+ mDCs in SF are involved in the inflammatory cascade intra-articularly by the secretion of specific T cell-attracting chemokines and the activation of self-reactive T cells.

Background: The soluble form of the interleukin 7 receptor (sIL-7R) is produced by fibroblasts after stimulation with proinflammatory cytokines. Increased sIL-7R serum and synovial fluid levels were recently demonstrated in patients with rheumatoid arthritis., Objectives: To investigate whether sIL-7R production is dysregulated in systemic lupus erythematosus (SLE), and whether this correlates with disease activity., Methods: Serum and urine sIL-7R concentrations were measured by ELISA, and sIL-7R quantitative PCR (qPCR) studies were performed in peripheral blood mononuclear cells (PBMCs). IL-7R, tumour necrosis factor α (TNFα), IL-1β and IL-17 immunostainings were performed on kidney sections., Results: sIL-7R concentrations were significantly higher in SLE sera than in controls, and correlated with SLE Disease Activity Index (SLEDAI) scores. Accordingly, serum sIL-7R levels were strongly raised in patients with nephritis. Moreover in patients with lupus nephritis, serum sIL-7R decreased upon treatment. sIL-7R gene expression in PBMCs was similar in patients with lupus nephritis and controls. By contrast, abundant perivascular IL-7R expression was seen in SLE kidney biopsy specimens, which was associated with expression of TNFα in the surrounding tissue., Conclusions: Our data indicate that sIL-7R is a marker of SLE disease activity, especially nephritis. In contrast to conventional disease activity markers, sIL-7R is not produced by immune cells, but might instead reflect activation of tissue cells in the target organ.

Objectives: To determine whether the presence of germinal centers (GCs) in salivary glands of patients with primary Sjögren's syndrome (pSS) is related to the severity of disease course and distinct immunopathology features., Methods: A systematic search was performed in September 2011 for terms and synonyms of Sjögren's syndrome and germinal centers. A total of 80 articles were retrieved, of which 16 were included for (meta-) analysis., Results: GC morphology was present in a mean ± SD 25.1 ± 5.0% of pSS patients. Mean lymphocyte focus scores were 1.25 points higher in patients with GCs as compared to those without GCs. Saliva production was reduced in patients with GCs, although this did not reach statistical significance. Percentages of patients positive for rheumatoid factor, anti-Sjögren's syndrome A (SSA), and anti-Sjögren's syndrome B (SSB) antibodies were significantly higher in patients with GCs (mean increase, 15%, 18%, and 18%, respectively). Additionally, patients with GCs were characterized by enhanced levels of local and systemic proinflammatory mediators. Importantly, these patients have a higher risk of lymphoma development (14% versus 1%)., Conclusions: Patients with GCs are characterized by more severe disease, although the small number of studies and their design hamper generalizability of results. The precise mechanisms that contribute to the development and persistence of germinal centers in pSS are largely unknown. This and the strongly increased risk of lymphoma development warrant intensive studies for the role of germinal centers in the immunopathology of pSS., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objectives: To investigate whether the immunomodulatory capacities of leflunomide are associated with clinical efficacy in the treatment of primary Sjögren's syndrome (SS) in a phase II pilot study., Methods: Peripheral blood mononuclear cells from 13 primary SS patients were obtained at baseline and after 24 weeks of leflunomide treatment. Ex-vivo production of interleukin (IL) 1β and tumour necrosis factor α (TNFα) and of interferon (IFN), IL-4, as well as TNFα ELISA measured production on T-cell and monocyte stimulation. In addition, the authors investigated the ability of leflunomide to influence systemic levels of inflammatory cytokines, as well as T-cell activation markers and the expression of IL-7 receptor α by flow cytometry. Correlations between changes in cytokine levels and changes in clinical response parameters were studied., Results: Ex-vivo production of IL-1β and TNFα was decreased at 24 weeks in the whole patient group, whereas IFN and IL-4 production were not significantly changed. However, a significant decrease in T-cell-stimulated IFN and TNFα production was observed in clinical responders, but not in non-responders. Moreover, significant correlations were found between increased sialometry values and decreased IFN and TNFα production. In addition, leflunomide reduced levels of inflammatory serum cytokines and CD40L expression, whereas it upregulated IL-7Rα expression on CD4 T cells with persistent serum IL-7 concentrations., Conclusions: Leflunomide treatment suppressed cytokine release from circulating immune cells. Inhibition of T-helper 1 cell cytokine production was related to clinical efficacy. This suggests that selective T-cell targeting might be a relevant therapeutic strategy in primary SS, possibly enhancing clinical efficacy and safety.

Objectives: To evaluate the performance of individual biomarkers and a multi-biomarker disease activity (MBDA) score in the early rheumatoid arthritis (RA) patient population from the computer assisted management in early rheumatoid arthritis (CAMERA) study., Methods: Twenty biomarkers were measured in the CAMERA cohort, in which patients were treated with either intensive or conventional methotrexate-based treatment strategies. The MBDA score was calculated using the concentrations of 12 biomarkers (SAA, IL-6, TNF-RI, VEGF-A, MMP-1, YKL-40, MMP-3, EGF, VCAM-1, leptin, resistin and CRP) according to a previously trained algorithm. The performance of the scores was evaluated relative to clinical disease activity assessments. Change in MBDA score over time was assessed by paired Wilcoxon rank sum test. Logistic regression was used to evaluate the ability of disease activity measures to predict radiographic progression., Results: The MBDA score had a significant correlation with the disease activity score based on 28 joints-C reactive protein (DAS28-CRP) (r=0.72; p<0.001) and an area under the receiver operating characteristic curve for distinguishing remission/low from moderate/high disease activity of 0.86 (p<0.001) using a DAS28-CRP cut-off of 2.7. In multivariate analysis the MBDA score, but not CRP, was an independent predictor of disease activity measures. Additionally, mean (SD) MBDA score decreased from 53 (18) at baseline to 39 (16) at 6 months in response to study therapy (p<0.0001). Neither MBDA score nor clinical variables were predictive of radiographic progression., Conclusions: This multi-biomarker test performed well in the assessment of disease activity in RA patients in the CAMERA study. Upon further validation, this test could be used to complement currently available disease activity measures and improve patient care and outcomes.

Objective: It has been reported that interleukin (IL)-10 limits blood-induced cartilage damage. Our aim was to study the effect of IL-4 alone and in combination with IL-10 on blood-induced cartilage damage., Design: Healthy human full thickness cartilage explants were cultured for 4 days in the presence of 50% v/v blood. IL-4, IL-10, or a combination of both cytokines was added during blood exposure. Cartilage matrix turnover was determined after a recovery period; additionally cytokine production, chondrocyte apoptosis, and expression of the IL-4 and IL-10 receptors were analyzed directly after exposure., Results: Blood-induced damage to the cartilage matrix was limited by IL-4 in a dose-dependent way (P<0.05). Also IL-10 limited this damage, although to a lesser extent (P<0.03). The effect of IL-4 plus IL-10 was more pronounced and protective than IL-10 alone (P<0.05). Production of IL-1β and tumor necrosis factor (TNF)-α was limited by both IL-4 and IL-10 (P<0.05), but more strongly by IL-4. Blood-induced apoptosis of chondrocytes was limited by IL-4 and the combination, and not by IL-10 alone. No direct beneficial effect of IL-4 or IL-10 on cartilage was found, however, the chondrocyte receptor expression of both cytokine receptors was upregulated by exposure to blood., Conclusions: This study demonstrates that IL-4 alone and in combination with IL-10 prevents blood-induced cartilage damage. Expectedly, anti-inflammatory effects on monocytes in the blood fraction and protective effects on chondrocytes are both involved. IL-4 in combination with IL-10 might be used to prevent blood-induced joint damage as a result of trauma or surgery., (Copyright © 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Introduction: We sought to investigate the capacity of interleukin (IL)-7 to enhance collagen-induced arthritis and to study by what mechanisms this is achieved., Methods: Mice received multiple injections with IL-7 or phosphate-buffered saline (PBS) as a control. Arthritis severity and incidence were determined by visual examination of the paws. Joint destruction was determined by assessing radiographs and immunohistochemistry of the ankle joints. Total cellularity and numbers of T-cell and B-cell subsets were assessed, as well as ex vivo production of interferon-γ (IFN-γ), IL-17, and IL-4. Proinflammatory mediators were measured in serum with multianalyte profiling., Results: IL-7 increased arthritis severity and radiology-assessed joint destruction. This was consistent with IL-7-increased intensity of cell infiltrates, bone erosions, and cartilage damage. Splenic CD19+ B cells and CD19+/GL7+ germinal center B cells, as well as CD4 and CD8 numbers, were increased by IL-7. IL-7 expanded memory T cells, associated with increased percentages of IFN-γ-, IL-4-, and IL-17-producing CD4+ T cells. On antigen restimulation of draining lymph node cells in vitro IL-7 treatment was found to increase IFN-γ and IL-17 production, whereas IL-4 was reduced. IL-7 also increased concentrations of proinflammatory mediators, indicative of T-cell activation (sCD40L), vascular activation (VCAM-1, VEGF), tissue destruction (fibroblast growth factor-basic (FGF-b), LIF), and chemotaxis (MIP-1γ, MIP-3β, lymphotactin, MDC, and MCP-5)., Conclusions: In arthritic mice, IL-7 causes expansion of T and B cells, associated with increased levels of proinflammatory mediators. IL-7 intensifies arthritis severity and joint destruction, accompanied by increased Th1 and Th17 activity. These data indicate that IL-7 could be an important mediator in arthritic conditions and that targeting IL-7 or its receptor represent novel therapeutic strategies.

Objective: To study the phenotypic characteristics of and the balance between systemic IL-7 receptor (IL-7R)α+ and IL-7Rα- Tregs in primary SS (pSS) patients as compared with control subjects and to assess the functional consequences this has for (IL-7-induced) T-cell activation., Methods: The functional properties of IL-7Rα+ and IL-7Rα- (CD25+) CD4 T cells from pSS patients were tested in vitro. Expression of CD25 and FoxP3 by IL-7Rα+ and IL-7Rα- CD4 T cells from pSS patients and healthy controls (HCs) were assessed. Also, the net ex vivo T-cell cytokine production and the capacity of IL-7 to activate total CD4 T cells from pSS patients compared with HCs in vitro was tested., Results: IL-7Rα+ T cells from pSS patients strongly proliferated and their numbers were slightly reduced compared with HCs. This reduced number was caused by an increase in both anergic and suppressive IL-7Rα- CD25+ T cells expressing high levels of FoxP3, but also by increases in IL-7Rα- CD25- CD4 T cells that only moderately expressed FoxP3. This altered balance in IL-7Rα+ and IL-7Rα- CD4 T cells was accompanied by unchanged ex vivo Th1, Th2 and Th17 cytokine production of total CD4 T cells. Furthermore, the increased numbers of IL-7Rα- CD25+ T cells did not prevent specific IL-7-induced Th1 and Th17 cytokine production by IL-7Rα+ T cells., Conclusion: IL-7Rα+ cells are highly proliferating cells that respond strongly to IL-7 despite an increased number of IL-7Rα- T cells that express FoxP3 and CD25. The recent finding that IL-7 and IL-7Rα+ T cells were both found to be increased in exocrine glands of pSS patients indicates that IL-7 could contribute to glandular inflammation by activation of IL-7Rα+ responder T cells despite the increased numbers of Tregs.

IL-7, expressed by stromal cells in primary lymphoid organs, is known for its critical role in the development and homeostatic expansion of T cells in humans and mice. IL-7 is equally important for B cell development in human and mice, but only in mice seems critical for B cell development and expansion. Recent studies demonstrate that this potent immunostimulatory cytokine is overexpressed in inflamed tissues of patients with (rheumatic) autoimmune diseases and that expression levels correlate with clinical parameters of disease. In inflamed tissues several cell types, including macrophages, dendritic cells, and fibroblasts produce IL-7. IL-7 primarily acts on T cells that abundantly express the IL-7 receptor and that are increased at the inflammatory sites, and predominantly induces Th1 and Th17-associated cytokine secretion. IL-7-mediated T cell-dependent activation of macrophages, dendritic cells and B cells is accompanied by up regulation of T cell differentiating factors, chemokines, adhesion/co-stimulatory molecules and catabolic cytokines and enzymes. Moreover, overexpression of IL-7 is associated with ectopic lymphoid aggregate formation, corresponding with the capacity of IL-7 to induce LTβ and TNFα and to activate innate lymphoid tissue inducer cells. Additionally, IL-7 promotes T cell-driven osteoclastogenesis and fibroblast activation, processes involved in tissue destruction in chronic inflammation. Altogether this suggests that IL-7 is an important proinflammatory mediator in several chronic (rheumatic) inflammatory autoimmune diseases. The substantial amelioration of inflammation and immunopathology in experimental animal models for these diseases by blocking IL-7(receptor) supports this role of IL-7 and demonstrates that IL-7 and its receptor represent novel targets for immunotherapy.

Objective: Human leukocyte-associated immunoglobulin-like receptor 1 (hLAIR-1) is an immune inhibitory receptor for collagen that is expressed on most immune cells. We previously showed that the LAIR-1-collagen interaction could be antagonized by the secreted homolog hLAIR-2, which can be detected in the synovial fluid of rheumatoid arthritis (RA) patients. In addition, the extracellular part of hLAIR-1 is a putative antagonist upon shedding from the cell membrane. The purpose of this study was to determine the relative roles of hLAIR-2 and soluble hLAIR-1 (shLAIR-1) in the regulation of the LAIR-1-collagen interaction., Methods: The ability of recombinant LAIR proteins to abrogate LAIR-1-collagen binding was tested by flow cytometry and adhesion assays. Collagen binding capacity was analyzed by surface plasmon resonance. Plasma, urine, and synovial fluid were screened for the presence of sLAIR-1 and LAIR-2 by enzyme-linked immunosorbent assay., Results: Recombinant LAIR-2 proteins abrogated the binding of collagen to LAIR-1 more efficiently than did recombinant sLAIR-1. Consistent with these findings, surface plasmon resonance analysis showed that LAIR-2 had a higher affinity for collagen than did LAIR-1. Activated CD4+ T cells were the main producers of LAIR-2, whereas the source of sLAIR-1 remains elusive. Both soluble LAIR-1 and LAIR-2 could be detected in the plasma and urine of healthy control subjects and patients with RA. Urinary levels of both proteins were significantly increased in RA patients, and LAIR-2 levels in urine were significantly correlated with markers of inflammation., Conclusion: Our data suggest that LAIR-2 is a more potent antagonist of LAIR-1 function in vivo, while both sLAIR-1 and LAIR-2 are potential biomarkers that may be used to monitor urine samples for evidence of systemic inflammation., (Copyright © 2011 by the American College of Rheumatology.)

Objectives: To investigate whether changes in bone density and turnover are associated with changes in inflammatory mediators in RA patients treated with glucocorticoids (GCs) upon vitamin D treatment in comparison with alendronate treatment., Methods: RA patients (n = 40) on long-term oral GC treatment received either alfacalcidol or alendronate. At baseline and after 18 months, we measured cytokines capable of antagonizing GCs [macrophage migration inhibitory factor (MIF), IL-13 and IL-7], cytokines causing T-cell differentiation (IL-6, IL-7, IL-12, IL-10 and IL-23) and cytokines produced by effector T cells (IFN-γ, IL-4, IL-17, IL-22). Associations of cytokine profiles with bone markers and BMD changes of the lumbar spine were explored using multiple regression analyses that corrected for study medication and risk factors of osteoporosis (gender, age, cumulative/change in GC dose)., Results: Alendronate, unlike alfacalcidol, increased BMD changes in the lumbar spine. Most cytokines were below detection limits. MIF and IL-23 were detectable in almost all samples; neither alfacalcidol nor alendronate significantly influenced serum concentrations of these cytokines. Interestingly, changes in MIF correlated positively with changes in BMD of the lumber spine (Pearson's correlation = 0.31), and in multivariate analysis adjusting for treatment, age and change in GC dose (P = 0.022)., Conclusion: During GC treatment, changes in the GC-antagonist MIF were positively correlated with changes in BMD, which could mean MIF has bone-protecting capacities in patients suffering from GC-induced bone destruction. Further studies need to validate the importance of these findings.

Objective: The interleukin-7 (IL-7)-related cytokine thymic stromal lymphopoietin (TSLP) is a potent activator of myeloid dendritic cells, enhancing Th2-mediated hypersensitivity, and it has been implicated in the pathogenesis of atopic diseases. Although intraarticular concentrations of TSLP have been shown to be increased in patients with rheumatoid arthritis (RA), the functional capacities of TSLP in arthritis are poorly studied. The purpose of this study was to investigate the effects of TSLP administration and TSLP receptor deficiency on immune activation, arthritis severity, and tissue destruction in T cell-driven arthritis models of RA., Methods: Immunopathology was studied in arthritic mice that were given multiple injections of murine recombinant TSLP and in mice that were deficient in the TSLP receptor (TSLPR(-/-)). Arthritis severity and incidence were determined by visual examination of the paws. Joint destruction was determined by assessing radiographs and the immunohistochemistry of ankle joints. Total cellularity and numbers of T cell subsets were assessed. Proinflammatory mediators were measured by multianalyte profiling of serum or paw protein extracts., Results: Administration of TSLP significantly exacerbated the severity of collagen-induced arthritis and the joint damage that was associated with increased T cell activation. Furthermore, TSLPR(-/-) mice had less severe arthritis than did wild-type mice. TSLPR(-/-) mice had diminished concentrations of local proinflammatory and catabolic mediators, including IL-17, IL-1β, IL-6, basic fibroblast growth factor, and matrix metalloproteinase 9, while levels of the regulatory cytokines IL-10 and IL-13 were increased., Conclusion: TSLP and its receptor enhance Th17-driven arthritis and tissue destruction in experimental arthritis. The increased expression of TSLP as well as the increased number of TSLPR-expressing cells in the joints of patients with RA suggest that TSLP and its receptor constitute novel therapeutic targets in RA., (Copyright © 2011 by the American College of Rheumatology.)