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Persons with rheumatoid arthritis (RA) or diabetes have increased risk of cardiovascular disease (CVD) and higher death rates compared to the general population. This study used data from the population-based Nord-Trøndelag Health Study (HUNT) and the Norwegian Cause of Death registry to compare all-cause mortality rates for RA or diabetes patients to the general population. We used Cox regression with age as time variable, adjusting for sex, smoking, body mass index, hypertension, total cholesterol, creatinine and previous CVD. To achieve proportional hazards, an interaction term with an age group variable (≤75 years or >75 years) was included for diabetes, smoking and previous CVD. Median follow-up was 18.1 years. Mortality occurred for 123 (32%) of the RA patients, 1,280 (44%) of the diabetes patients, 17 (52%) of the patients with both diseases and 11,641 (18%) of the controls. Both diseases were associated with statistically significantly increased mortality rates. The hazard ratio (HR) for RA was 1.24 (95% CI: 1.03-1.44). The HR of diabetes was 1.82 (1.60-2.04) for individuals ≤75 years old and 1.49 (1.39-1.59) for individuals >75 years. Diabetes had a significantly higher HR for death than RA for participants ≤75 years, but not significantly different for participants >75 years. © The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Background IL-6 receptor (IL-6R) signaling drives development of T cell populations important to type 1 diabetes pathogenesis. We evaluated whether blockade of IL-6R with monoclonal antibody tocilizumab would slow loss of residual β cell function in newly diagnosed type 1 diabetes patients. Methods We conducted a multicenter, randomized, placebo-controlled, double-blind trial with tocilizumab in new-onset type 1 diabetes. Participants were screened within 100 days of diagnosis. Eligible participants were randomized 2:1 to receive 7 monthly doses of tocilizumab or placebo. The primary outcome was the change from screening in the mean AUC of C-peptide collected during the first 2 hours of a mixed meal tolerance test at week 52 in pediatric participants (ages 6–17 years). Results There was no statistical difference in the primary outcome between tocilizumab and placebo. Immunophenotyping showed reductions in downstream signaling of the IL-6R in T cells but no changes in CD4 memory subsets, Th17 cells, Tregs, or CD4+ T effector cell resistance to Treg suppression. A DC subset decreased during therapy but regressed to baseline once therapy stopped. Tocilizumab was well tolerated. Conclusion Tocilizumab reduced T cell IL-6R signaling but did not modulate CD4+ T cell phenotypes or slow loss of residual β cell function in newly diagnosed individuals with type 1 diabetes. Trial Registration ClinicalTrials.gov NCT02293837. Funding NIH National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and National Institute of Allergy and Infectious Diseases (NIAID) UM1AI109565, UL1TR000004 from NIH/National Center for Research Resources (NCRR) Clinical and Translational Science Award (CTSA), NIH/NIDDK P30DK036836, NIH/NIDDK U01DK103266, NIH/NIDDK U01DK103266, 1UL1TR000064 from NIH/NCRR CTSA, NIH/National Center for Advancing Translational Sciences (NCATS) UL1TR001878, UL1TR002537 from NIH/CTSA; National Health and Medical Research Council Practitioner Fellowship (APP1136735), NIH/NIDDK U01-DK085476, NIH/CTSA UL1-TR002494, Indiana Clinical and Translational Science Institute Award UL1TR002529, Vanderbilt Institute for Clinical and Translational Research UL1TR000445. NIH/NCATS UL1TR003142, NIH/CTSA program UL1-TR002494, Veteran Affairs Administration, and 1R01AI132774.

Antigen-specific immunotherapy (ASI) holds great promise for type 1 diabetes (T1D). Preclinical success for this approach has been demonstrated in vivo, however, clinical translation is still pending. Reasons explaining the slow progress to approve ASI are complex and span all stages of research and development, in both academic and industry environments. The basic four hurdles comprise a lack of translatability of pre-clinical research to human trials; an absence of robust prognostic and predictive biomarkers for therapeutic outcome; a need for a clear regulatory path addressing ASI modalities; and the limited acceptance to develop therapies intervening at the pre-symptomatic stages of disease. The core theme to address these challenges is collaboration—early, transparent, and engaged interactions between academic labs, pharmaceutical research and clinical development teams, advocacy groups, and regulatory agencies to drive a fundamental shift in how we think and treat T1D.

ObjectiveTo investigate baseline use of biologic or targeted synthetic (b/ts) disease-modifying antirheumatic drugs (DMARDs) and COVID-19 outcomes in rheumatoid arthritis (RA).MethodsWe analysed the COVID-19 Global Rheumatology Alliance physician registry (from 24 March 2020 to 12 April 2021). We investigated b/tsDMARD use for RA at the clinical onset of COVID-19 (baseline): abatacept (ABA), rituximab (RTX), Janus kinase inhibitors (JAKi), interleukin 6 inhibitors (IL-6i) or tumour necrosis factor inhibitors (TNFi, reference group). The ordinal COVID-19 severity outcome was (1) no hospitalisation, (2) hospitalisation without oxygen, (3) hospitalisation with oxygen/ventilation or (4) death. We used ordinal logistic regression to estimate the OR (odds of being one level higher on the ordinal outcome) for each drug class compared with TNFi, adjusting for potential baseline confounders.ResultsOf 2869 people with RA (mean age 56.7 years, 80.8% female) on b/tsDMARD at the onset of COVID-19, there were 237 on ABA, 364 on RTX, 317 on IL-6i, 563 on JAKi and 1388 on TNFi. Overall, 613 (21%) were hospitalised and 157 (5.5%) died. RTX (OR 4.15, 95% CI 3.16 to 5.44) and JAKi (OR 2.06, 95% CI 1.60 to 2.65) were each associated with worse COVID-19 severity compared with TNFi. There were no associations between ABA or IL6i and COVID-19 severity.ConclusionsPeople with RA treated with RTX or JAKi had worse COVID-19 severity than those on TNFi. The strong association of RTX and JAKi use with poor COVID-19 outcomes highlights prioritisation of risk mitigation strategies for these people.

Ankylosing spondylitis (AS) is a chronic inflammatory disease with hallmarks of both autoimmune and autoinflammatory pathology. In this Review, the authors examine the evidence for both disease processes and aim to reconcile the two.Ankylosing spondylitis (AS) is a chronic inflammatory disorder of unknown aetiology. Unlike other systemic autoimmune diseases, in AS, the innate immune system has a dominant role characterized by aberrant activity of innate and innate-like immune cells, including gamma delta T cells, group 3 innate lymphoid cells, neutrophils, mucosal-associated invariant T cells and mast cells, at sites predisposed to the disease. The intestine is involved in disease manifestations, as it is at the forefront of the interaction between the mucosal-associated immune cells and the intestinal microbiota. Similarly, biomechanical factors, such as entheseal micro-trauma, might also be involved in the pathogenesis of the articular manifestation of AS, and sentinel immune cells located in the entheses could provide links between local damage, genetic predisposition and the development of chronic inflammation. Although these elements might support the autoinflammatory nature of AS, studies demonstrating the presence of autoantibodies (such as anti-CD74, anti-sclerostin and anti-noggin antibodies) and evidence of activation and clonal expansion of T cell populations support an autoimmune component to the disease. This Review presents the evidence for autoinflammation and the evidence for autoimmunity in AS and, by discussing the pathophysiological factors associated with each, aims to reconcile the two hypotheses.

Transient partial remission, a period of low insulin requirement experienced by most patients soon after diagnosis, has been associated with mechanisms of immune regulation. A better understanding of such natural mechanisms of immune regulation might identify new targets for immunotherapies that reverse type 1 diabetes (T1D). In this study, using Cox model multivariate analysis, we validated our previous findings that patients with the highest frequency of CD4+CD25+CD127hi (127-hi) cells at diagnosis experience the longest partial remission, and we showed that the 127-hi cell population is a mix of Th1- and Th2-type cells, with a significant bias toward antiinflammatory Th2-type cells. In addition, we extended these findings to show that patients with the highest frequency of 127-hi cells at diagnosis were significantly more likely to maintain β cell function. Moreover, in patients treated with alefacept in the T1DAL clinical trial, the probability of responding favorably to the antiinflammatory drug was significantly higher in those with a higher frequency of 127-hi cells at diagnosis than those with a lower 127-hi cell frequency. These data are consistent with the hypothesis that 127-hi cells maintain an antiinflammatory environment that is permissive for partial remission, β cell survival, and response to antiinflammatory immunotherapy.

Objective Type 1 diabetes (T1D) is an autoimmune disorder in which autoreactive T cells destroy insulin‐producing β‐cells. Interventions that preserve β‐cell function represent a fundamental therapeutic goal in T1D and biomarkers that predict and monitor β‐cell function, and changes in islet autoantigenic signatures are needed. As proinsulin and neoantigens derived from proinsulin peptides (hybrid insulin peptides, HIPs) are important T1D autoantigens, we analysed peripheral blood CD4+ T‐cell autoantigen‐specific proliferative responses and their relationship to estimated β‐cell function. Methods We recruited 72 people with and 42 without T1D, including 17 pre‐diabetic islet antibody‐positive and 9 antibody‐negative first‐degree relatives and 16 unrelated healthy controls with T1D‐risk HLA types. We estimated C‐peptide level at 3‐month intervals for 2 years post‐diagnosis and measured CD4+ T‐cell proliferation to proinsulin epitopes and HIPs using an optimised bioassay. Results We show that CD4+ T‐cell proliferation to any islet peptide and to multiple epitopes were significantly more frequent in pre‐diabetic islet antibody‐positive siblings and participants with T1D ≤ 3 months of duration, than in participants with T1D > 3 months or healthy controls. Among participants with T1D and first‐degree relatives, CD4+ T‐cell proliferation occurred most frequently in response to proinsulin33‐63 (full‐length C‐peptide). Proinsulin33‐63‐specific responses were associated with HLA‐DR3‐DQ2 and/or HLA‐DR4/DQ8. In children with T1D, proinsulin33‐63‐specific T‐cell proliferation positively associated with concurrent estimated C‐peptide and predicted survival in honeymoon. Conclusion CD4+ T‐cell proliferative responses to proinsulin‐containing autoantigens are common before and immediately after diagnosis of T1D but decline thereafter. Proinsulin33‐63‐specific CD4+ T‐cell response is a novel marker of estimated residual endogenous β‐cell function and predicts a better 2‐year disease outcome., In this study, we found CD4+ T‐cell proliferative responses to proinsulin‐containing autoantigens are common before and immediately after diagnosis of type 1 diabetes but decline thereafter. Proinsulin33‐63‐specific CD4+ T‐cell response is a novel marker that correlates with increased estimated endogenous insulin production.

Objectives Adoptive transfer of chimeric antigen receptor (CAR)‐modified T cells is a form of cancer immunotherapy that has achieved remarkable efficacy in patients with some haematological cancers. However, challenges remain in CAR T‐cell treatment of solid tumours because of tumour‐mediated immunosuppression. Methods We have demonstrated that CAR T‐cell stimulation through T‐cell receptors (TCRs) in vivo can generate durable responses against solid tumours in a variety of murine models. Since Clec9A‐targeting tailored nanoemulsion (Clec9A‐TNE) vaccine enhances antitumour immune responses through selective activation of Clec9A+ cross‐presenting dendritic cells (DCs), we hypothesised that Clec9A‐TNE could prime DCs for antigen presentation to CAR T cells through TCRs and thus improve CAR T‐cell responses against solid tumours. To test this hypothesis, we used CAR T cells expressing transgenic TCRs specific for ovalbumin (OVA) peptides SIINFEKL (CAROTI) or OVA323‐339 (CAROTII). Results We demonstrated that the Clec9A‐TNEs encapsulating full‐length recombinant OVA protein (OVA‐Clec9A‐TNE) improved CAROT T‐cell proliferation and inflammatory cytokine secretion in vitro. Combined treatment using the OVA‐Clec9A‐TNE and CAROT cells resulted in durable responses and some rejections of tumours in immunocompetent mice. Tumour regression was accompanied by enhanced CAROT cell proliferation and infiltration into the tumours. Conclusion Our study presents Clec9A‐TNE as a prospective avenue to enhance CAR T‐cell efficacy for solid cancers., Clec9A‐targeting tailored nanoemulsion (Clec9A‐TNE) induced extensive proliferation, persistence and activation of chimeric antigen receptor (CAR) T cells, leading to the eradication of solid tumours in murine models. This novel approach could lead to the development of new CAR T‐cell therapies against some common solid tumour types in patients.

Background: Mucosal-associated invariant T (MAIT) cells are innate-like T cells that recognise bacterial metabolites presented by MHC class I-related protein 1 (MR1). Bacterial dysbiosis has been implicated in auto-inflammatory disease development. We investigated MAIT cells in early, untreated rheumatoid arthritis (RA) and spondyloarthritis (SpA) patients.Methods: Blood and synovial fluid mononuclear cells obtained from patients (SpA/RA) and controls were stimulated with fixed Escherichia coli to provide MAIT ligand. Cells were analysed by flow cytometry and MAIT cells were identified by MR1-5-OP-RU tetramers. Synovial biopsies were studied by confocal microscopy.Results: Peripheral and synovial CD3+ MR1-tet+ MAIT cell frequencies were comparable in all groups. MAIT cells were detected in RA and SpA synovium based on CD3, CD161 and Vα7.2 expression. Peripheral RA MAIT cells were mostly CD4+ (controls 8.3%, SpA 12.3%, RA 52.6%; p p E. coli stimulation (control, CD25 MFI = 177, CD69 MFI = 1307; SpA, CD25 MFI = 95, CD69 MFI = 1257; RA, CD25 MFI = 0, CD69 MFI = 467; p p = 0.01 respectively).Conclusion: In early untreated RA patients, the peripheral MAIT cell composition was altered, with reduced levels of CD161 expression, and cells were hyporesponsive to stimulation. MAIT cell dysfunction may provide a link between the microbiome and development of RA.

Polymorphisms impacting thymic function may decrease peripheral tolerance and hasten autoimmune disease. The NF-κB transcription factor subunit, RelB, is essential for the development and differentiation of medullary thymic epithelial cells (mTECs): RelB-deficient mice have reduced thymic cellularity and markedly fewer mTECs, lacking AIRE. The precise mechanism of this mTEC reduction in the absence of RelB is unclear. To address this, we studied mTECs and dendritic cells (DCs), which critically regulate negative selection, and thymic regulatory T-cells (tTreg) in RelB−/− mice, which have spontaneous multiorgan autoimmune disease. RelB−/− thymi were organized, with medullary structures containing AIRE− mTECs, DCs, and CD4+ thymocytes, but fewer tTreg. Granulocytes infiltrated the RelB−/− thymic cortex, capsule, and medulla, producing inflammatory thymic medullary atrophy, which could be treated by granulocyte depletion or RelB+ DC immunotherapy, with concomitant recovery of mTEC and tTreg numbers. These data indicate that central tolerance defects may be accelerated by autoimmune thymic inflammation where impaired RelB signaling impairs the medullary niche, and may be reversible by therapies enhancing peripheral Treg or suppressing inflammation.

Background Clinician-scientists are in decline worldwide. They represent a unique niche in medicine by bridging the gap between scientific discovery and patient care. A national, integrated approach to training clinician-scientists, typically programs that comprise a comprehensive MD-PhD pathway, are customary. Such a pathway is lacking in Australia. The objective was to gather perceptions from Australian medical students on factors they perceive would influence their decision to pursue clinician-scientist training. Methods A cross-sectional mixed methods design used quantitative and qualitative questions in an online self-report survey with medical students from a four-year MD program. Quantitative measures comprised scaled response questions regarding prior experience and current involvement in research, and short- and long-term opinions about factors that influence their decisions to undertake a research higher degree (RHD) during medical school. Qualitative questions gathered broader perceptions of what a career pathway as a clinician-scientist would include and what factors are most conducive to a medical student’s commitment to MD-PhD training. Results Respondents (N = 418; 51% female) indicated Time, Funding and Pathway as the major themes arising from the qualitative data, highlighting negative perceptions rather than possible benefits to RHD training. The lack of an evident Pathway was inter-related to Time and Funding. Themes were supported by the quantitative data. Sixty percent of students have previous research experience of varying forms, and 90% report a current interest, mainly to improve their career prospects. Conclusions The data emphasise the need for an MD-PhD pathway in Australia. A model that provides an early, integrated, and exclusive approach to research training pathways across all stages of medical education is suggested as the best way to rejuvenate the clinician-scientist. A national pathway that addresses factors influencing career decision making throughout the medical education continuum should include an appropriate funding structure, and provide early and continuing advice and mentoring. It should be flexible, gender equitable, and include post-graduate training. The implications of implementing MD-PhD programs represent a substantial investment. However this should not be a deterrent to Australia’s commitment to an MD-PhD pathway, but rather a challenge to help ensure our future healthcare is guided by highly trained and competent clinician-scientists.

ObjectiveThe pathogenetic mechanisms by which HLA-DRB1 alleles are associated with anticitrullinated peptide antibody (ACPA)-positive rheumatoid arthritis (RA) are incompletely understood. RA high-risk HLA-DRB1 alleles are known to share a common motif, the ‘shared susceptibility epitope (SE)’. Here, the electropositive P4 pocket of HLA-DRB1 accommodates self-peptide residues containing citrulline but not arginine. HLA-DRB1 His/Phe13β stratifies with ACPA-positive RA, while His13βSer polymorphisms stratify with ACPA-negative RA and RA protection. Indigenous North American (INA) populations have high risk of early-onset ACPA-positive RA, whereby HLA-DRB1*04:04 and HLA-DRB1*14:02 are implicated as risk factors for RA in INA. However, HLA-DRB1*14:02 has a His13βSer polymorphism. Therefore, we aimed to verify this association and determine its molecular mechanism.MethodsHLA genotype was compared in 344 INA patients with RA and 352 controls. Structures of HLA-DRB1*1402-class II loaded with vimentin-64Arg59-71, vimentin-64Cit59-71 and fibrinogen β−74Cit69-81 were solved using X-ray crystallography. Vimentin-64Cit59-71-specific and vimentin59-71-specific CD4+ T cells were characterised by flow cytometry using peptide-histocompatibility leukocyte antigen (pHLA) tetramers. After sorting of antigen-specific T cells, TCRα and β-chains were analysed using multiplex, nested PCR and sequencing.ResultsACPA+ RA in INA was independently associated with HLA-DRB1*14:02. Consequent to the His13βSer polymorphism and altered P4 pocket of HLA-DRB1*14:02, both citrulline and arginine were accommodated in opposite orientations. Oligoclonal autoreactive CD4+ effector T cells reactive with both citrulline and arginine forms of vimentin59-71 were observed in patients with HLA-DRB1*14:02+ RA and at-risk ACPA- first-degree relatives. HLA-DRB1*14:02-vimentin59-71-specific and HLA-DRB1*14:02-vimentin-64Cit59-71-specific CD4+ memory T cells were phenotypically distinct populations.ConclusionHLA-DRB1*14:02 broadens the capacity for citrullinated and native self-peptide presentation and T cell expansion, increasing risk of ACPA+ RA.

Objective. Self-reported diagnoses of inflammatory arthritis are not accurate. The primary study aim was to ascertain self-reported diagnoses of rheumatoid arthritis (RA) and ankylosing spondylitis (AS) in the Norwegian population-based Nord-Trøndelag Health Study (HUNT) using hospital case files. The secondary aim was to provide updated estimates of the prevalence and incidence of RA and AS. Methods. All inhabitants ≥ 20 years old from the county of Nord-Trøndelag were invited. Data from 70,805 unique participants from HUNT2 (1995–1997) and HUNT3 (2006–2008) were included. For participants who self-reported RA or AS, case files from all 3 hospitals in the catchment area were evaluated using standardized diagnostic criteria. Results. Of 2703 self-reported cases of RA, 19.1% were verified in hospital files. Of 1064 self-reported cases of AS, 15.8% were verified. Of 259 cases self-reporting both RA and AS, 8.1% had RA and 5.4% had AS. Overall, a self-report of 1 or both diagnoses could not be verified in 82.1%, including 22.8% with insufficient information or no case file. The prevalence of RA was 768 (95% CI 705–835) per 100,000. The incidence of RA from HUNT2 to HUNT3 was 0.48 (0.41–0.56) per 1000 per year. The prevalence of AS was 264 (228–305) per 100,000. The incidence of AS from HUNT2 to HUNT3 was 0.19 (0.15–0.24) per 1000 per year. Conclusion. Self-reported diagnoses of RA and AS are often false-positive. The prevalence and incidence of RA were comparable to reports from similar populations. The incidence of AS was higher than previously reported in a mixed population from Norway. © 2017. This is a pre-copy-editing, author-produced PDF of an article accepted for publication in The Journal of Rheumatology following peer review. LOCKED until 1.8.2018 due to copyright restrictions. The definitive publisher-authenticated version [Self-reported diagnosis of rheumatoid arthritis or ankylosing spondylitis has low accuracy: Data from the Nord-Trøndelag Health Study] is available online at: http://www.jrheum.org/content/44/8/1134

A comprehensive structural portrait of the association between citrullination, the HLA-DRB1 locus, and T cell autoreactivity in rheumatoid arthritis., Rheumatoid arthritis (RA) is strongly associated with the human leukocyte antigen (HLA)-DRB1 locus that possesses the shared susceptibility epitope (SE) and the citrullination of self-antigens. We show how citrullinated aggrecan and vimentin epitopes bind to HLA-DRB1*04:01/04. Citrulline was accommodated within the electropositive P4 pocket of HLA-DRB1*04:01/04, whereas the electronegative P4 pocket of the RA-resistant HLA-DRB1*04:02 allomorph interacted with arginine or citrulline-containing epitopes. Peptide elution studies revealed P4 arginine–containing peptides from HLA-DRB1*04:02, but not from HLA-DRB1*04:01/04. Citrullination altered protease susceptibility of vimentin, thereby generating self-epitopes that are presented to T cells in HLA-DRB1*04:01+ individuals. Using HLA-II tetramers, we observed citrullinated vimentin- and aggrecan-specific CD4+ T cells in the peripheral blood of HLA-DRB1*04:01+ RA-affected and healthy individuals. In RA patients, autoreactive T cell numbers correlated with disease activity and were deficient in regulatory T cells relative to healthy individuals. These findings reshape our understanding of the association between citrullination, the HLA-DRB1 locus, and T cell autoreactivity in RA.

The immune system has evolved to survey and respond appropriately to the universe of foreign pathogens, while at the same time deploying an intricate repertoire of mechanisms that keep responses to host tissues in check. For the adaptive immune system, specificity and sensitivity are provided by a large repertoire of antigen T-cell receptors (TCRs) constructed in their extracellular domain to recognize antigenic peptide fragments restricted and presented by histocompatibility complex molecules, and coupled through intracellular domains to signal transduction modules that serve to transmit environmental cues inside the cell. In this review we consider recent evidence that has provided insight into how altered TCR signaling thresholds could contribute to human autoimmune arthritis, including rheumatoid arthritis (RA), and the spondyloarthropathies (SpA). We also discuss mechanistic studies that demonstrate how perturbations of T-cell antigen receptor signaling in the SKG mouse model can promote systemic autoimmunity and the intersection with essential innate immune pathways that lead to the development of chronic inflammatory phenotypes.

In animals, immunomodulatory dendritic cells (DCs) exposed to autoantigen can suppress experimental arthritis in an antigen-specific manner. In rheumatoid arthritis (RA), disease-specific anti-citrullinated peptide autoantibodies (ACPA or anti-CCP) are found in the serum of about 70% of RA patients and are strongly associated with HLA-DRB1 risk alleles. This study aimed to explore the safety and biological and clinical effects of autologous DCs modified with a nuclear factor κB (NF-κB) inhibitor exposed to four citrullinated peptide antigens, designated "Rheumavax," in a single-center, open-labeled, first-in-human phase 1 trial. Rheumavax was administered once intradermally at two progressive dose levels to 18 human leukocyte antigen (HLA) risk genotype-positive RA patients with citrullinated peptide-specific autoimmunity. Sixteen RA patients served as controls. Rheumavax was well tolerated: adverse events were grade 1 (of 4) severity. At 1 month after treatment, we observed a reduction in effector T cells and an increased ratio of regulatory to effector T cells; a reduction in serum interleukin-15 (IL-15), IL-29, CX3CL1, and CXCL11; and reduced T cell IL-6 responses to vimentin(447-455)-Cit450 relative to controls. Rheumavax did not induce disease flares in patients recruited with minimal disease activity, and DAS28 decreased within 1 month in Rheumavax-treated patients with active disease. This exploratory study demonstrates safety and biological activity of a single intradermal injection of autologous modified DCs exposed to citrullinated peptides, and provides rationale for further studies to assess clinical efficacy and antigen-specific effects of autoantigen immunomodulatory therapy in RA.

International audience; Objective The spondyloarthritides share genetic susceptibility, interleukin-23 (IL-23) dependence, and the involvement of microbiota. The aim of the current study was to elucidate how host genetics influence gut microbiota and the relationship between microbiota and organ inflammation in spondyloarthritides. Methods BALB/c ZAP-70(W163C)-mutant (SKG) mice, Toll-like receptor 4 (TLR-4)-deficient SKG mice, and wild-type BALB/c mice were housed under specific pathogen-free conditions. SKG and wild-type BALB/c mice were maintained under germ-free conditions, and some of these mice were recolonized with altered Schaedler flora. All of the mice were injected intraperitoneally with microbial -1,3-glucan (curdlan). Arthritis, spondylitis, and ileitis were assessed histologically. Microbiome composition was analyzed in serial fecal samples obtained from mice that were co-housed beginning at the time of weaning, using 454 pyrosequencing. Infiltrating cells and cytokines in the peritoneal cavity were measured by flow cytometry and enzyme-linked immunosorbent assay. Cytokine, endoplasmic reticulum (ER) stress marker, and tight junction protein transcription was measured by quantitative real-time polymerase chain reaction. Results Microbiota content and response to curdlan varied according to whether T cell receptor signal strength was normal or was impaired due to the ZAP-70(W163C) mutation. Curdlan triggered acute inflammation regardless of the presence of the SKG allele or microbiota. However, no or limited microbiota content attenuated the severity of arthritis. In contrast, ileal IL-23 expression, ER stress, lymph node IL-17A production, goblet cell loss, and ileitis development were microbiota-dependent. Ileitis but not arthritis was suppressed by microbiota transfer upon co-housing SKG mice with wild-type BALB/c mice, as well as by TLR-4 deficiency. Conclusion The interaction between immunogenetic background and host microbiota leads to an IL-23-dependent loss of mucosal function, triggering ileitis in response to curdlan.

The severity of malaria can range from asymptomatic to lethal infections involving severe anaemia and cerebral disease. However, the molecular and cellular factors responsible for these differences in disease severity are poorly understood. Identifying the factors that mediate virulence will contribute to developing antiparasitic immune responses. Since immunity is initiated by dendritic cells (DCs), we compared their phenotype and function following infection with either a nonlethal or lethal strain of the rodent parasite, Plasmodium yoelii, to identify their contribution to disease severity. DCs from nonlethal infections were fully functional and capable of secreting cytokines and stimulating T cells. In contrast, DCs from lethal infections were not functional. We then transferred DCs from mice with nonlethal infections to mice given lethal infections and showed that these DCs mediated control of parasitemia and survival. IL-12 was necessary for survival. To our knowledge, our studies have shown for the first time that during a malaria infection, DC function is essential for survival. More importantly, the functions of these DCs are determined by the strain of parasite. Our studies may explain, in part, why natural malaria infections may have different outcomes., Author Summary Malaria is a complex disease and there is little data on why Plasmodium infections have different outcomes that can range from asymptomatic to lethal infections. Since immunity is initiated by dendritic cells (DCs), several studies have investigated DC function during malaria. Current data on the effects of infection on DC functions are inconclusive, with one school of thought being that DC function is normal and the other that DC function is compromised. However, these studies have used different species and strains of Plasmodium. We have compared DC function during a lethal and nonlethal infection and found significant differences. Our study shows that the strain of parasite determines if DCs remain functional following infection. Moreover, by transferring DCs between mice, we show that DC function is essential for survival from a lethal infection. This study offers some insight into the current controversy and offers a plausible explanation for differences in the severity of disease.

Self-reactive T cells with low signalling capacity through the T-cell receptor were recently observed in the SKG mouse model of rheumatoid arthritis (RA) and have been linked to a spontaneous mutation in the ZAP-70 signal transduction molecule. Here we hypothesize that similar mechanisms also drive RA, associated with an abnormal innate and adaptive immune response driven by nuclear factor-kappaB activation and tumour necrosis factor secretion. Similar to the essential role played by pathogens in SKG mice, we propose that HLA-associated immunity to chronic viral infection is a key factor in the immune dysregulation and joint inflammation that characterize RA.

Objective: Gut-derived innate lymphoid cell 3 (ILC3) has been shown to participate in the pathogenesis of ankylosing spondylitis (AS). CX3CR1+ mononuclear phagocytes (MNPs) have been demonstrated to modulate ILC3 function in the gut. This study was undertaken to investigate the role of proinflammatory CX3CR1+CD59+ MNPs in modulating ILC3 function in AS patients. Methods: MNP subsets in the blood of AS patients and controls were analyzed by flow cytometry. The presence of CX3CR1+CD59+ cells in tissue was confirmed by confocal microscopy. Expression of the proinflammatory chemokines CX3CL1 and CCL2 and decoy receptor 6 (DcR-6) was analyzed. Peripheral CX3CR1+CD59+ cells were cocultured with ILC3, and changes in their frequency were evaluated by flow cytometry. Transcriptome analysis of circulating CX3CR1+ monocytes was also performed. Results: DcR-6 deficiency and CCL2 overexpression were observed in inflamed tissues from AS patients. In the gut, the proinflammatory CX3CR1+CD59+ MNP population was expanded, correlated with the presence of bacteria, and produced high levels of tumor necrosis factor–like molecule 1A (TL1A) and interleukin-23 (IL-23). MNPs positive for CD11b, CD11c, and major histocompatibility complex class II, predominantly expressing CX3CR1, were also expanded in the small intestines of treatment-naive SKG relative to BALB/c mice. The frequency of gut-derived CX3CR1+CD59+CCR9+TL1A+IL-23+ MNPs was significantly higher in the peripheral blood and synovial fluid of AS patients than controls. CCR9+CX3CR1+CD59+ monocytes were also expanded in AS synovial and bone marrow samples. Transcriptome analysis of isolated CX3CR1+CD59+ monocytes demonstrated a specific proinflammatory profile in AS. Isolated proinflammatory CX3CR1+CD59+ MNPs from AS patients induced the expansion and activation of ILC3. Conclusion: Proinflammatory CX3CR1+CD59+TL1A+IL-23+ MNPs are expanded in AS patients and display a specific proinflammatory transcriptome profile. Given the ability of these cells to support ILC3 expansion, they may promote a sustained proinflammatory status in AS.

Antigen-specific suppression of a previously primed immune response is a major challenge for immunotherapy of autoimmune disease. RelB activation is required for myeloid DC differentiation. Here, we show that antigen-exposed DCs in which RelB function is inhibited lack cell surface CD40, prevent priming of immunity, and suppress previously primed immune responses. DCs generated from CD40-deficient mice similarly confer suppression. Regulatory CD4 + T cells induced by the DCs transfer antigen-specific "infectious" tolerance to primed recipients in an interleukin-10-dependent fashion. Thus CD40, regulated by RelB activity, determines the consequences of antigen presentation by myeloid DCs. These observations have significance for autoimmune immunotherapy and suggest a mechanism by which peripheral tolerance might be constitutively maintained by RelB − CD40 − DCs.

Summary Autoimmune diseases, including rheumatoid arthritis, develop and persist due to impaired immune self-tolerance, which has evolved to regulate inflammatory responses to injury or infection. After diagnosis, patients rarely achieve drug-free remission, and although at-risk individuals can be identified with genotyping, antibody tests, and symptoms, rheumatoid arthritis cannot yet be successfully prevented. Precision medicine is increasingly offering solutions to diseases that were previously considered to be incurable, and immunotherapy has begun to achieve this aim in cancer. Comparatively, modulating autoantigen-specific immune responses with immunotherapy for the cure of autoimmune diseases is at a relatively immature stage. Current treatments using non-specific immune or inflammatory suppression increase susceptibility to infection, and are rarely curative. However, early stage clinical trials suggesting that immunotherapy might allow extended duration of remission and even prevention of progression to disease suggest modulating tolerance in rheumatoid arthritis could be a promising opportunity for therapy.