Simon Stebbings

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.

A comparison of fatigue correlates in rheumatoid arthritis and osteoarthritis: disparity in associations with disability, anxiety and sleep disturbance

OBJECTIVES To investigate correlates of fatigue among individuals with RA and OA, including mood, sleep, disease activity and radiographic damage. METHODS Fatigue was assessed using the Multidimensional Assessment of Fatigue-Global Fatigue Index (MAF-GFI) in 103 patients with RA and 103 with OA. Sleep disturbance and pain were assessed using a visual analogue scale anxiety and depression using the Hospital Anxiety and Depression scale and disability using the HAQ. In the RA cohort, the disease activity score-28 joint count (DAS-28) and the Van der Heijde modified Sharp score were calculated, and in the OA cohort, the Kellgren-Lawrence score and the WOMAC score calculated. RESULTS The MAF-GFI scores were higher in the OA cohort (P = 0.02). This was not significant after controlling for disability (P = 0.59). OA participants reported greater pain, disability, depression and sleeplessness than those with RA (all P < 0.01). The strongest correlates of fatigue in the RA cohort were depression (P < 0.001) and anxiety (P < 0.001). There was no significant association with pain (P = 0.43), DAS-28 (P = 0.07), HAQ (P = 0.10) or Sharp score (P = 0.78). In OA, the correlates of fatigue were older age (P = 0.02), sleep disturbance (P = 0.03), depression (P = 0.04), disability (P = 0.04) and lower CRP (P = 0.001). CONCLUSIONS Fatigue is common and severe in both RA and OA. In RA, fatigue had no significant association with pain, disease activity, disability or erosions, but was associated with depression and anxiety. The disparity in correlates indicates that generalizing the experience of fatigue between OA and RA is not appropriate. Fatigue is an important domain in the assessment of disease impact.

The Role of the Microbiome in Rheumatic Diseases

There is a growing understanding of the mechanisms by which the influence of the microbiota projects beyond sites of primary mucosal occupation to other human body systems. Bacteria present in the intestinal tract exert a profound effect on the host immune system, both locally and at distant sites. The oral cavity has its own characteristic microbiota, which concentrates in periodontal tissues and is in close association with a permeable epithelium. In this review we examine evidence which supports a role for the microbiome in the aetiology of rheumatic disease. We also discuss how changes in the composition of the microbiota, particularly within the gastrointestinal tract, may be affected by genetics, diet, and use of antimicrobial agents. Evidence is presented to support the theory that an altered microbiota is a factor in the initiation and perpetuation of inflammatory diseases, including rheumatoid arthritis (RA), spondyloarthritis (SpA), and inflammatory bowel disease (IBD). Mechanisms through which the microbiota may be involved in the pathogenesis of these diseases include altered epithelial and mucosal permeability, loss of immune tolerance to components of the indigenous microbiota, and trafficking of both activated immune cells and antigenic material to the joints. The potential to manipulate the microbiome, by application of probiotics and faecal microbial transplant (FMT), is now being investigated. Both approaches are in their infancy with regard to management of rheumatic disease but their potential is worthy of consideration, given the need for novel therapeutic approaches, and the emerging recognition of the importance of microbial interactions with human hosts.

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.

Probiotic Therapy for the Treatment of Spondyloarthritis: A Randomized Controlled Trial

Objective. To investigate the effect of an orally administered probiotic on disease activity, fatigue, quality of life, and intestinal symptoms in patients with active spondyloarthritis. Methods. Patients with active spondyloarthritis [defined as Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 3, Bath Ankylosing Spondylitis Functional Index (BASFI) ≥ 3, Maastricht Ankylosing Spondylitis Enthesitis Score (MASES) ≥ 2, or peripheral joint count ≥ 2] were randomized to oral probiotic or placebo for 12 weeks. Patients and assessors were blinded to treatment allocation. The primary outcome measure was 10% improvement in the BASFI. Additional outcome measures were improvements in the ASsessments in Ankylosing Spondylitis (ASAS)-endorsed core domains: pain, spinal mobility, patient global, peripheral joint and entheseal scores, stiffness, C-reactive protein, and fatigue. The ASAS20 criteria, a composite measure of response, were also applied. Quality of life and bowel symptoms were quantified using the Ankylosing Spondylitis Quality of Life Questionnaire (ASQoL) and Dudley Inflammatory Bowel Symptom Questionnaire (DISQ). Results. Sixty-three patients were randomized to oral probiotic (n = 32) or placebo (n = 31). All patients completed the trial. No significant difference was noted between groups in any of the core domains. The mean BASFI fell from 3.5 ± 2.0 to 2.9 ± 1.9 in the probiotic group and from 3.6 ± 1.9 to 3.1 ± 2.2 in the placebo group (p = 0.839). The mean BASDAI fell from 4.2 ± 2.2 to 3.2 ± 2.1 in the probiotic group and 4.5 ± 2.0 to 3.9 ± 2.2 in the placebo group (p = 0.182). No significant adverse events were recorded in the probiotic-treated group. Conclusion. In this randomized controlled trial, the probiotic combination administered did not demonstrate significant benefit over placebo, despite a theoretical rationale for this therapy.

Yoga for Functional Ability, Pain and Psychosocial Outcomes in Musculoskeletal Conditions: A Systematic Review and Meta-Analysis

OBJECTIVES Musculoskeletal conditions (MSCs) are the leading cause of disability and chronic pain in the developed world, impacting both functional ability and psychosocial health. The current review investigates the effectiveness of yoga on primary outcomes of functional ability, pain and psychosocial outcomes across a range of MSCs. METHODS A comprehensive search of 20 databases was conducted for full-text, randomized controlled trials of yoga in clinically diagnosed MSCs. RESULT Seventeen studies met the inclusion criteria, involving 1,626 participants with low back pain (LBP), osteoarthritis (OA), rheumatoid arthritis (RA), kyphosis or fibromyalgia. Studies were quality rated, and analysed for the effect of yoga on primary outcomes, immediately post-intervention. Twelve studies were rated as good quality. Yoga interventions resulted in a clinically significant improvement in functional outcomes in mild-to-moderate LBP and fibromyalgia, and showed a trend to improvement in kyphosis. Yoga significantly improved pain in OA, RA and mild-to-severe LBP. Psychosocial outcomes were significantly improved in mild-to-moderate LBP and OA. Meta-analysis of good-quality studies showed a moderate treatment effect for yoga of -0.64 (95%CI -0.89 to -0.39) for functional outcomes and -0.61 (95%CI -0.97 to -0.26) for pain outcomes. CONCLUSIONS Evidence suggests that yoga is an acceptable and safe intervention, which may result in clinically relevant improvements in pain and functional outcomes associated with a range of MSCs. Future analysis of outcomes which take into account the amount of yoga received by participants may provide insight into any putative duration or dosage effects of yoga interventions for MSCs.

Development of a health index in patients with ankylosing spondylitis (ASAS HI): final result of a global initiative based on the ICF guided by ASAS

Objectives The burden of disease in patients with ankylosing spondylitis (AS) can be considerable. However, no agreement has been reached among expert members of Assessment of SpondyloArthritis International Society (ASAS) to define severity of AS. Based on the International Classification of Functioning, Disability and Health (ICF), a core set of items for AS has been selected to represent the entire spectrum of possible problems in functioning. Based on this, the objective of this study was to develop a tool to quantify health in AS, the ASAS Health Index. Methods First, based on a literature search, experts’ and patients’ opinion, a large item pool covering the categories of the ICF core set was generated. In several steps this item pool was reduced based on reliability, Rasch analysis and consensus building after two cross-sectional surveys to come up with the best fitting items representing most categories of the ICF core set for AS. Results After the first survey with 1754 patients, the item pool of 251 items was reduced to 82. After selection by an expert committee, 50 items remained which were tested in a second cross-sectional survey. The results were used to reduce the number of items to a final set of 17 items. This selection showed the best reliability and fit to the Rasch model, no residual correlation, and absence of consistent differential item function and a Person Separation Index of 0.82. Conclusions In this long sequential study, 17 items which cover most of the ICF core set were identified that showed the best representation of the health status of patients with AS. The ASAS Health Index is a linear composite measure which differs from other measures in the public domain.

The immune response to autologous bacteroides in ankylosing spondylitis is characterized by reduced interleukin 10 production.

Objective. Ileocolitis is a recognized feature of ankylosing spondylitis (AS) and is likely to play a role in the pathogenesis of AS, in conjunction with the normal intestinal microbiota. In order to investigate the host immune response in AS, we measured cytokines in tissue culture following exposure of peripheral blood mononuclear cells (PBMC) to autologous colonic bacteria. Methods. Twenty-one patients with AS and 21 matched controls were recruited. Subjects in the AS group were assessed clinically. Bacteroides species belonging to the B. fragilis group were selectively cultured from stool samples and paired with blood samples from each participant. Ten cultures of autologous Bacteroides were randomly selected from cultures grown from the fecal specimens of each of the 21 patients with AS and 21 controls. These were then tested for reactivity with PBMC and the cytokines produced by proliferating lymphocytes [interleukin 10 (IL-10), IL-17, interferon-γ, tumor necrosis factor-α] were measured in cell culture supernatants. Differences between groups were analyzed using censored normal regression analysis. Results. The patients with AS had severe active AS with Bath AS Disease Activity Index 5.5 (± 1.6) and C-reactive protein (mg/l) 13.8 (± 12.2) (mean ± standard deviation). IL-10 concentrations in ex vivo assay supernatants were lower in the AS group compared with controls (p = 0.047). There were no statistically significant differences between the groups for other cytokines. Conclusion. In AS, reduced IL-10 production in response to stimulation with autologous Bacteroides cultures may represent a mechanism by which intestinal inflammation develops and persists, a situation analogous to inflammatory bowel disease.

STIR MRI to direct muscle biopsy in suspected idiopathic inflammatory myopathy.

Successful management of the idiopathic inflammatory myopathies requires an early and accurate diagnosis. The muscle biopsy remains the definitive test. However, false-negative biopsy results are common, as the disease is typically patchy in distribution. The advent of short tau inversion recovery sequences now allows rapid magnetic resonance imaging of the whole body to be performed, enabling identification of the muscles most suitable for biopsy. It also provides further diagnostic information through the form and anatomic distribution of the pathology. We report 2 cases illustrating the advantages of whole-body short tau inversion recovery magnetic resonance imaging before muscle biopsy. We encourage clinicians to use the technique in this context.

The effects of an orally administered probiotic on sulfasalazine metabolism in individuals with rheumatoid arthritis: a preliminary study

Aim:  To carry out a pilot study to investigate the effect of short‐term oral probiotic administration on the metabolism of sulfasalazine (SSZ) in patients with rheumatoid arthritis (RA) stabilized on SSZ.