Arthritis prevention in the pre-clinical phase of RA with abatacept (the APIPPRA study): a multi-centre, randomised, double-blind, parallel-group, placebo-controlled clinical trial protocol.

TRIAL DESIGN: We present a study protocol for a multi-centre, randomised, double-blind, parallel-group, placebo-controlled trial that seeks to test the feasibility, acceptability and effectiveness of a 52-week period of treatment with the first-in-class co-stimulatory blocker abatacept for preventing or delaying the onset of inflammatory arthritis. METHODS: The study aimed to recruit 206 male or female subjects from the secondary care hospital setting across the UK and the Netherlands. Participants who were at least 18 years old, who reported inflammatory sounding joint pain (clinically suspicious arthralgia) and who were found to be positive for serum autoantibodies associated with rheumatoid arthritis (RA) were eligible for enrolment. All study subjects were randomly assigned to receive weekly injections of investigational medicinal product, either abatacept or placebo treatment over the course of a 52-week period. Participants were followed up for a further 52 weeks. The primary endpoint was defined as the time to development of at least three swollen joints or to the fulfilment of the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for RA using swollen but not tender joints, whichever endpoint was met first. In either case, swollen joints were confirmed by ultrasonography. Participants, care givers, and those assessing the outcomes were all blinded to group assignment. Clinical assessors and ultrasonographers were also blinded to each other's assessments for the duration of the study. CONCLUSIONS: There is limited experience of the design and implementation of trials for the prevention of inflammatory joint diseases. We discuss the rationale behind choice and duration of treatment and the challenges associated with defining the "at risk" state and offer pragmatic solutions in the protocol to enrolling subjects at risk of RA. TRIAL REGISTRATION: Current Controlled Trials, ID: ISRCTN46017566 . Registered on 4 July 2014.

Detection of a microbial metabolite by STING regulates inflammasome activation in response to Chlamydia trachomatis infection.

The innate immune system is a critical component of host defence against microbial pathogens, but effective responses require an ability to distinguish between infectious and non-infectious insult to prevent inappropriate inflammation. Using the important obligate intracellular human pathogen Chlamydia trachomatis; an organism that causes significant immunopathology, we sought to determine critical host and pathogen factors that contribute to the induction of inflammasome activation. We assayed inflammasome activation by immunoblotting and ELISA to detect IL-1ß processing and LDH release to determine pyroptosis. Using primary murine bone marrow derived macrophages or human monocyte derived dendritic cells, infected with live or attenuated Chlamydia trachomatis we report that the live organism activates both canonical and non-canonical inflammasomes, but only canonical inflammasomes controlled IL-1ß processing which preceded pyroptosis. NADPH oxidase deficient macrophages were permissive to Chlamydia trachomatis replication and displayed elevated type-1 interferon and inflammasome activation. Conversely, attenuated, non-replicating Chlamydia trachomatis, primed but did not activate inflammasomes and stimulated reduced type-1 interferon responses. This suggested bacterial replication or metabolism as important factors that determine interferon responses and inflammasome activation. We identified STING but not cGAS as a central mediator of interferon regulated inflammasome activation. Interestingly, exogenous delivery of a Chlamydia trachomatis metabolite and STING ligand-cyclic di-AMP, recovered inflammasome activation to attenuated bacteria in a STING dependent manner thus indicating that a bacterial metabolite is a key factor initiating inflammasome activation through STING, independent of cGAS. These data suggest a potential mechanism of how the innate immune system can distinguish between infectious and non-infectious insult and instigate appropriate immune responses that could be therapeutically targeted.

Clinical experience with the European Ankylosing Spondylitis Infliximab Cohort (EASIC): long-term extension over 7 years with focus on clinical efficacy and safety.

OBJECTIVES: Knowledge on the long-term effects of anti-TNF therapy in patients with ankylosing spondylitis (AS) is still limited. Our objective was to study the long-term efficacy and safety of anti-TNF therapy in AS. METHODS: After having completed the first part of the EASIC trial a total of 71 patients were enrolled into this 96-week extension study. Patients were treated with the same dosages and dosing intervals of infliximab as in the EASIC core study. Efficacy was assessed by using standardised assessment tools such as BASDAI, BASFI, BASMI, patient global assessment, CRP levels and the proportion of patients without any sign of enthesitis or arthritis. Long-term safety was assessed by documenting adverse events (AE), serious adverse events (SAE) and reasons for dropping out. RESULTS: Of the 71 patients included, 64 (90.1%) completed the trial , and 7 discontinued: one was lost to follow-up, 3 withdrew informed consent and in 3 patients therapy was stopped for different reasons: secondary loss of response, recurrent infections and basal cell carcinoma of the skin. The completers showed rather stable low scores of BASDAI (mean 2.4, median 2.52), BASFI (mean 3.1, median 2.76) and BASMI (mean 3.2, median 3) as well as patients global assessment and CRP. The vast majority of patients did not have enthesitis or arthritis. A total of 476 AE were observed, 13 of which were SAE. The majority of these were infections and most of them affected the respiratory tract. Two malignancies occurred: one basal cell carcinoma and one malignant melanoma. These were the only SAE judged to be possibly related to the study drug. CONCLUSIONS: Anti-TNF treatment with infliximab is efficacious over long periods of time in patients with AS. The observation of two skin related malignancies, including one melanoma, during the whole study period of 7 years is in line with reports from previous large AS data sets.

TCR usage, gene expression and function of two distinct FOXP3(+)Treg subsets within CD4(+)CD25(hi) T cells identified by expression of CD39 and CD45RO.

FOXP3+ regulatory T (Treg) cells are indispensable for immune homeostasis, but their study in humans is complicated by heterogeneity within Treg, the difficulty in purifying Tregs using surface marker expression (e.g. CD25) and the transient expression of FOXP3 by activated effector cells. Here, we report that expression of CD39 and CD45RO distinguishes three sub-populations within human CD4(+)CD25(hi) T cells. Initial phenotypic and functional analysis demonstrated that CD4(+)CD25(hi)CD39(+)CD45RO(+) cells had properties consistent with effector Treg, CD4(+)CD25(hi)CD39(-)CD45RO(-) cells were naïve Treg and CD4(+)CD25(hi)CD39(-)CD45RO(+) cells were predominantly non-Treg with effector T-cell function. Differences in these two newly identified Treg subsets were corroborated by studies of gene expression and TCR analysis. To apply this approach, we studied these two newly identified Treg subsets in ankylosing spondylitis, and showed impairment in both effector and naïve Treg. This work highlights the importance of discriminating Treg subsets to enable proper comparisons of immune regulatory capacity in healthy individuals and those with inflammatory disease.

Major histocompatibility complex associations of ankylosing spondylitis are complex and involve further epistasis with ERAP1.

Ankylosing spondylitis (AS) is a common, highly heritable, inflammatory arthritis for which HLA-B*27 is the major genetic risk factor, although its role in the aetiology of AS remains elusive. To better understand the genetic basis of the MHC susceptibility loci, we genotyped 7,264 MHC SNPs in 22,647 AS cases and controls of European descent. We impute SNPs, classical HLA alleles and amino-acid residues within HLA proteins, and tested these for association to AS status. Here we show that in addition to effects due to HLA-B*27 alleles, several other HLA-B alleles also affect susceptibility. After controlling for the associated haplotypes in HLA-B, we observe independent associations with variants in the HLA-A, HLA-DPB1 and HLA-DRB1 loci. We also demonstrate that the ERAP1 SNP rs30187 association is not restricted only to carriers of HLA-B*27 but also found in HLA-B*40:01 carriers independently of HLA-B*27 genotype.

Th17 and Th22 cells in psoriatic arthritis and psoriasis.

INTRODUCTION: The aim of this study was to characterize interleukin 17 (IL-17) and interleukin 22 (IL-22) producing cells in peripheral blood (PB), skin, synovial fluid (SF) and synovial tissue (ST) in patients with psoriasis (Ps) and psoriatic arthritis (PsA). METHODS: Flow cytometry was used to enumerate cells making IL-22 and IL-17, in skin and/or SF and PB from 11 patients with Ps and 12 patients with PsA; skin and PB of 15 healthy controls and SF from rheumatoid arthritis (RA) patients were used as controls. Expression of the interleukin 23 receptor (IL-23R) and chemokine receptors CCR4 and CCR6 was examined. Secretion of IL-17 and IL-22 was measured by ELISA. ST was analysed by immunohistochemical staining of IL-17 and IL-22. RESULTS: Increased frequencies of IL-17+ and IL-22+ CD4+ T cells were seen in PB of patients with PsA and Ps. IL-17 secretion was significantly elevated in both PsA and Ps, whilst IL-22 secretion was higher in PsA compared to Ps and healthy controls. A higher proportion of the CD4+ cells making IL-17 or IL-22 expressed IL-23R and frequencies of IL-17+, CCR6+ and CCR4+ T cells were elevated in patients with Ps and those with PsA. In patients with PsA, CCR6+ and IL-23R + T cells numbers were elevated in SF compared to PB. Increased frequencies of IL-17+ and IL-22+ CD4+ T cells were demonstrated in Ps skin lesions. In contrast, whilst elevated frequencies of CD4+ IL-17+ cells were seen in PsA SF compared to PB, frequencies of CD4+ IL-22+ T cells were lower. Whereas IL-17 expression was equivalent in PsA, osteoarthritis (OA) and RA ST, IL-22 expression was higher in RA than either OA or PsA ST, in which IL-22 was strikingly absent. CONCLUSIONS: Elevated frequencies of IL-17 and IL-22 producing CD4+ T cells were a feature of both Ps and PsA. However their differing distribution at disease sites, including lower frequencies of IL-22+ CD4+ T cells in SF compared to skin and PB, and lack of IL-22 expression in ST suggests that Th17 and Th22 cells have common, as well as divergent roles in the pathogenesis of Ps and PsA.

Identification of multiple risk variants for ankylosing spondylitis through high-density genotyping of immune-related loci.

Ankylosing spondylitis is a common, highly heritable inflammatory arthritis affecting primarily the spine and pelvis. In addition to HLA-B*27 alleles, 12 loci have previously been identified that are associated with ankylosing spondylitis in populations of European ancestry, and 2 associated loci have been identified in Asians. In this study, we used the Illumina Immunochip microarray to perform a case-control association study involving 10,619 individuals with ankylosing spondylitis (cases) and 15,145 controls. We identified 13 new risk loci and 12 additional ankylosing spondylitis-associated haplotypes at 11 loci. Two ankylosing spondylitis-associated regions have now been identified encoding four aminopeptidases that are involved in peptide processing before major histocompatibility complex (MHC) class I presentation. Protective variants at two of these loci are associated both with reduced aminopeptidase function and with MHC class I cell surface expression.

Mutations in the selenocysteine insertion sequence-binding protein 2 gene lead to a multisystem selenoprotein deficiency disorder in humans.

Selenium, a trace element that is fundamental to human health, is incorporated into some proteins as selenocysteine (Sec), generating a family of selenoproteins. Sec incorporation is mediated by a multiprotein complex that includes Sec insertion sequence-binding protein 2 (SECISBP2; also known as SBP2). Here, we describe subjects with compound heterozygous defects in the SECISBP2 gene. These individuals have reduced synthesis of most of the 25 known human selenoproteins, resulting in a complex phenotype. Azoospermia, with failure of the latter stages of spermatogenesis, was associated with a lack of testis-enriched selenoproteins. An axial muscular dystrophy was also present, with features similar to myopathies caused by mutations in selenoprotein N (SEPN1). Cutaneous deficiencies of antioxidant selenoenzymes, increased cellular ROS, and susceptibility to ultraviolet radiation-induced oxidative damage may mediate the observed photosensitivity. Reduced levels of selenoproteins in peripheral blood cells were associated with impaired T lymphocyte proliferation, abnormal mononuclear cell cytokine secretion, and telomere shortening. Paradoxically, raised ROS in affected subjects was associated with enhanced systemic and cellular insulin sensitivity, similar to findings in mice lacking the antioxidant selenoenzyme glutathione peroxidase 1 (GPx1). Thus, mutation of SECISBP2 is associated with a multisystem disorder with defective biosynthesis of many selenoproteins, highlighting their role in diverse biological processes.

Mechanisms of Disease: the immunopathogenesis of spondyloarthropathies.

Research into the pathogenesis of the spondyloarthropathies has examined the role of HLA-B27 and other genes in susceptibility to these diseases. Novel characteristics of HLA-B27 have been discovered, which have allowed hypotheses for an influence of HLA-B27 on disease to be developed that do not reflect its ability to present arthritogenic peptides to CD8(+) T cells. Although a role for CD8(+) T cells has not been excluded, they are not required in the HLA-B27 transgenic rat model, and do not dominate at sites of disease in humans. Studies have also focused on the consequences of the (rather inefficient) intracellular folding of the HLA-B27 heavy chain, the ability of cells to deal with intracellular infection, and their expression of unusual forms of HLA-B27 on cell surfaces (including free heavy chains and dimers). Unusual surface forms of HLA-B27 interact with a different set of receptors from those that recognize conventional class I MHC molecules and thus can be implicated in driving inflammatory responses. Additional candidate susceptibility genes are being identified, either using gene-targeting technology in mice, or genomic screening approaches in humans. In several cases, as with HLA-B27, the evidence suggests that these genes influence the response of the host to bacteria, including pathogens and commensal organisms of the skin and gastrointestinal tract. The concept that spondyloarthropathies are the result of interactions between susceptibility genes, bacteria and the immune system remains a useful model for the pathogenesis of these diseases.

Heat shock protein 60: identification of specific epitopes for binding to primary macrophages.

In the present study, we characterized regions of human heat shock protein (HSP) 60 responsible for binding to primary macrophages. Studies using 20-mer peptides of the HSP60 sequence to compete with HSP60-binding to macrophages from C57BL/6J mice showed that regions aa241-260, aa391-410 and aa461-480 are involved in surface-binding. HSP60 mutants, lacking the N-terminal 137, 243 or 359 amino acids, inhibited HSP60-binding to primary macrophages to different degrees, demonstrating that all three regions are required for optimal binding. Analysis of different pro- and eukaryotic HSP60 species indicated that phylogenetically separate HSP60 species use different binding sites on primary macrophages.

Identification of the heat shock protein 60 epitope involved in receptor binding on macrophages.

In the present study, we identified the human heat shock protein 60 (HSP60) epitope responsible for binding to macrophages. Studies using overlapping 15- and 20-mer peptides of the human HSP60 sequence to compete with binding of HSP60 to macrophages indicated that surface binding was accounted for by the region aa481-500. Deletion mutants of HSP60, lacking the N-terminal 137, 243 or 359 amino acids, strongly inhibited HSP60 binding to macrophages. Monoclonal antibodies addressing regions aa1-200, aa335-366 or aa383-447 did not block HSP60 binding. We conclude that a single C-terminal region, aa481-500, accounts for the binding of HSP60 to macrophages.

Cardiovascular risk factors and atherosclerosis in young males: ARMY study (Atherosclerosis Risk-Factors in Male Youngsters).

BACKGROUND: Necropsy studies suggest that atherosclerosis begins in childhood, but in vivo confirmation of this concept is sparse and limited to selected population samples. Furthermore, new risk concepts of atherosclerosis focusing on inflammation, infections, and immunity have not yet been evaluated in this age group. METHODS AND RESULTS: This study was conducted in a sample of 141 17- to 18-year-old white males homogenous in age and sex. In addition to classic risk factors, C-reactive protein and the humoral and cellular immune reactivity to heat-shock proteins (HSPs) were assessed. Intima-media thickness (IMT) was quantified at 4 vessel segments of the carotid and femoral arteries. High IMT was considered to be present if the IMT of at least 1 vessel segment exceeded the 90th percentile. In a multivariate logistic regression analysis, cigarette smoking, high diastolic blood pressure, prominent immune reactivity to human and/or mycobacterial HSP60s, alcohol consumption (inverse), and low HDL cholesterol levels were all associated with high IMT. The prevalence of high IMT substantially increased from 0 to 60% when the number of risk conditions in a single individual increased from 0 to 4 (P<0.001 for linear trend). CONCLUSIONS: Our study supports the concept that atherosclerosis begins in the first decades of life and suggests a role of the immune system, especially immunoreactivity against HSP60s, in atherosclerosis of young individuals.