Spondyloarthritis: update on pathogenesis and management

Exploring the role of gut microbes in spondyloarthritis: Implications for pathogenesis and therapeutic strategies

The gut microbiota plays a pivotal role in regulating host immunity, and dysregulation of this interaction is implicated in autoimmune and inflammatory diseases, including spondyloarthritis (SpA). This review explores microbial dysbiosis and altered metabolic function observed in various forms of SpA, such as ankylosing spondylitis (AS), psoriatic arthritis (PsA), acute anterior uveitis (AAU), and SpA-associated gut inflammation. Studies on animal models and clinical samples highlight the association between gut microbial dysbiosis, metabolic perturbations and immune dysregulation in SpA pathogenesis. These studies have received impetus through next-generation sequencing methods, which have enabled the characterization of gut microbial composition and function, and host gene expression. Microbial/metabolomic studies have revealed potential biomarkers and therapeutic targets, such as short-chain fatty acids, and tryptophan metabolites, offering insights into disease mechanisms and treatment approaches. Further studies on microbial function and its modulation of the immune response have uncovered molecular mechanisms underlying various SpA. Understanding the complex interplay between microbial community structure and function holds promise for improved diagnosis and management of SpA and other autoimmune disorders.

Role of the Gut Microbiota in Osteoarthritis, Rheumatoid Arthritis, and Spondylarthritis: An Update on the Gut-Joint Axis

Dysregulation of the gut microbiota and their metabolites is involved in the pathogenic process of intestinal diseases, and several pieces of evidence within the current literature have also highlighted a possible connection between the gut microbiota and the unfolding of inflammatory pathologies of the joints. This dysregulation is defined as the "gut-joint axis" and is based on the joint-gut interaction. It is widely recognized that the microbiota of the gut produce a variety of compounds, including enzymes, short-chain fatty acids, and metabolites. As a consequence, these proinflammatory compounds that bacteria produce, such as that of lipopolysaccharide, move from the "leaky gut" to the bloodstream, thereby leading to systemic inflammation which then reaches the joints, with consequences such as osteoarthritis, rheumatoid arthritis, and spondylarthritis. In this state-of-the-art research, the authors describe the connections between gut dysbiosis and osteoarthritis, rheumatoid arthritis, and spondylarthritis. Moreover, the diagnostic tools, outcome measures, and treatment options are elucidated. There is accumulating proof suggesting that the microbiota of the gut play an important part not only in immune-mediated, metabolic, and neurological illnesses but also in inflammatory joints. According to the authors, future studies should concentrate on developing innovative microbiota-targeted treatments and their effects on joint pathology as well as on organizing screening protocols to predict the onset of inflammatory joint disease based on gut dysbiosis.

Association between syndecan-4 and subclinical atherosclerosis in ankylosing spondylitis

BACKGROUND

Despite advances in the diagnosis and treatment of ankylosing spondylitis (AS), the risk of cardiovascular complications in AS patients is still higher than in the general population. Macrophages are at the intersection of the basic pathogenetic processes of AS and atherosclerosis. Although syndecan-4 (SDC4) mediates a variety of biological processes, the role of SDC4 in macrophage-mediated atherogenesis in AS patients remains unclear. Herein, we aimed to investigate the role of SDC4 in subclinical atherosclerosis in AS patients.

METHODS

Subjects were selected from eligible AS patients and control subjects without a prior history of AS who were referred to the rheumatology outpatient clinics. All participants' past medical records and clinical, and demographic characteristics were scanned. In addition, carotid intima-media thickness (CIMT) measurement and disease activity index measurement were applied to all patients.

RESULTS

According to our data, serum SDC4 level was significantly higher among AS patients compared with the control group (6.7 [1.5-35.0] ng/mL vs 5.1 [0.1-12.5] ng/mL, P < .001). The calculated CIMT was also significantly higher in AS patients than in the control group (0.6 [0.3-0.9] mm vs 0.4 (0.2-0.7), P < .001]. Additionally, serum C-reactive protein level and SDC4 level were independent predictors of AS and strongly associated with CIMT. Linear regression analysis showed that serum SDC4 level was the best predictor of CIMT (P = .004).

CONCLUSION

Our data indicate that serum SDC4 levels provide comprehensive information about the clinical activity of the disease and subclinical atherosclerosis in AS patients.

Prevalence of HLA B27 in Patients Diagnosed with Ankylosing Spondylitis (AS) in Diyarbakır, Southeastern Region of Turkey

AIM

The research to be conducted on human leukocyte antigen (HLA)-B27 in patients diagnosed with ankylosing spondylitis (AS) in Diyarbakır between 2019-2021 is to contribute to the understanding of the prevalence and effect of this genetic marker in the local population. As a researcher working on HLA-B27 and AS, our focus is to research the following. HLA-B27 Prevalence: To determine the prevalence of HLA-B27 in patients diagnosed with AS during the specified period in Diyarbakır. This information can provide insight into the genetic factors associated with the disease in the local population. Disease Severity: Investigate the relationship between HLA-B27 positivity and severity of AS symptoms. To examine factors such as disease progression, pain levels, functional impairment, and quality of life in HLA-B27 positive patients compared to HLA-B27 negative patients. By Genetic Associations: To enable the discovery of potential genetic relationships between HLA-B27 and other genetic markers known to be associated with AS. To investigate whether there are any specific genetic variants associated with HLA-B27 that contribute to disease susceptibility or severity. Researchers: We recommend considering the following approaches to generate knowledge on this topic globally: Literature Review: Conducting a comprehensive review of the available scientific literature on HLA-B27 and AS. It is to describe relevant studies conducted globally and summarize their findings to provide a broader understanding of the subject. Collaboration and Data Sharing: To encourage cooperation with researchers from other regions or countries doing similar studies on HLA-B27 and ASs. By sharing our data and collaborating on analysis, we can improve the global perspective and generalizability of your findings. International Conferences and Journals: Presenting our research findings at international conferences focusing on rheumatology, genetics or related fields. To disseminate our findings globally is to submit your research articles to reputable journals specializing in AS or genetic studies. Online Platforms: Using online platforms such as Researchgate.net, academia.edu or social media networks to share our research findings, connect with other researchers in the field and participate in discussions on a global scale. By using these fields, it is possible to contribute to the global knowledge and understanding of the relationship between HLA-B27 and AS. It is also to obtain insights from studies carried out in other regions.

MATERIALS AND METHODS

198 (104 male and 94 female) patients who applied to Dicle University Faculty of Medicine Physical Therapy and Rehabilitation Clinic with AS symptoms between 2019-2021 and were referred to Dicle University Medical Biology and Genetics Department for evaluation. HLA-B27 positivity was included in our study as a case group. As the control group, 50 people (25 males, 25 females) were selected among the unrelated people who applied to our laboratory to be a bone marrow donor. In both groups, DNA isolation was performed from peripheral blood using the salt precipitation method. Rotar Gene Q device was used for real-time PCR analysis. As a statistical method in analysis; The prevalences of the variables of interest were calculated. The lower and upper limits of 95% were determined as the confidence interval. According to the presence of HLA 27 positivity, the mean of ESR, CRP, and age variables were compared. Mann-Whitney U test was used due to the small number of subjects. Also, correlations between ESR and CRP were calculated. Spearman rho correlation statistics were used as a statistical method. Analyzed.

RESULT

Radiological examinations and laboratory tests were performed on 198 patients with suspicion AS and 50 healthy control group of 248 subjects. The prevalence of those with a definite diagnosis of AS was calculated as statistical analysis recalculated 20.16 (95% CI: 0.76-0.9552). The prevalence of HLA-B27 in 50 patients diagnosed with AS as a result of radiological examinations and laboratory tests was calculated as 92%.

CONCLUSION

Our study is the first study covering the province of Diyarbakır in the Southeastern Anatolia Region, which we think will contribute to the literature in the evaluation of HLA-B27 positivity in AS patients. The prevalence of HLA-B27 in our region is higher than the prevalence in Turkey.

CC-99677, a novel, oral, selective covalent MK2 inhibitor, sustainably reduces pro-inflammatory cytokine production

BACKGROUND

Mitogen-activated protein kinase (MAPK)-activated protein kinase-2 (MK2) is activated downstream of p38 MAPK and regulates stability of mRNAs encoding inflammatory cytokines. CC-99677 is a novel, irreversible, covalent MK2 inhibitor under development for the treatment of ankylosing spondylitis (AS) and other inflammatory diseases. As part of a phase I clinical trial to assess safety and tolerability, we evaluated target engagement, pharmacokinetics, and pharmacodynamics of CC-99677.

METHODS

The MK2 inhibitor CC-99677 was evaluated for its effect on cytokine expression in vitro in peripheral blood mononuclear cells (PBMCs) from healthy donors and patients with a definitive AS diagnosis. A novel in vitro model was developed to compare the potential for tachyphylaxis of CC-99677 and p38 inhibitors in THP-1 cells. The effect of CC-99677 on tristetraprolin (TTP) and cytokine mRNA was assessed in stimulated human monocyte-derived macrophages. In a first-in-human study, thirty-seven healthy volunteers were randomly assigned to daily oral doses of CC-99677 or placebo, and blood was collected at pre-specified time points before and after dosing. CC-99677 concentrations were assessed in the plasma, and CC-99677 binding to MK2 was evaluated in PBMCs. Ex vivo stimulation of the whole blood was conducted from participants in the first-in-human study to assess the pharmacodynamic effects.

RESULTS

In vitro, CC-99677 inhibited tumor necrosis factor (TNF), interleukin (IL)-6, and IL-17 protein production in samples of monocytes and macrophages from AS patients and healthy volunteers via an mRNA-destabilization mechanism. In the in vitro model of tachyphylaxis, CC-99677 showed a differentiated pattern of sustained TNF protein inhibition compared with p38 inhibitors. CC-99677 reduced TTP phosphorylation and accelerated the decay of inflammatory cytokine mRNA in lipopolysaccharide-stimulated macrophages. Administration of CC-99677 to healthy volunteers was safe and well-tolerated, with linear pharmacokinetics and sustained reduction of ex vivo whole blood TNF, IL-6, and chemokine synthesis.

CONCLUSIONS

CC-99677 inhibition of MK2 is a promising approach for the treatment of inflammatory diseases and may overcome the limitations of p38 MAPK inhibition.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03554993 .

A Case of Axial Spondyloarthritis Triggered by SARS-CoV-2 Infection

Ever since the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there has been a noticeable change in atypical presentations of several rheumatological diseases following COVID-19 infections. In this case report, we present a case of SARS-CoV-2-induced axial and peripheral spondyloarthritis. This case highlights the possibility of SARS-CoV-2 infection accelerating the onset of autoimmune diseases such as axial spondyloarthritis. Although uncommon, these cases warrant a referral to the rheumatologist for appropriate diagnosis and management. This case also highlights the need for further research on the mechanisms behind the viral interaction of SARS-CoV-2 infections with the host immune system, especially about accelerating the onset of autoimmune diseases.

The Use of Janus Kinase Inhibitors in Axial Spondyloarthritis: Current Insights

Current pharmacological treatments of axial spondyloarthritis (axSpA) are limited to non-steroidal anti-inflammatory drugs (NSAIDs) and biological agents, including TNFα inhibitors and IL-17 inhibitors. Despite the availability of these agents, many patients either fail to respond adequately, lose their initial therapeutic response over time, or develop undesirable side effects, thus highlighting the need for new treatment options. Janus kinase (JAK) and signal transducers and activators of transcription (STAT) are a group of intracellular kinases that play a role in the signaling pathway induced by cytokines and certain growth factors associated with the inflammatory process of axSpA. There are several lines of evidence implicating the JAK–STAT pathway in the pathophysiological process of axSpA, including genetic data, the use of certain JAK in the intracellular signal of specific cytokines involved in axSpA (IL-23, IL-22, and IL-6), and data from experimental models of SpA. This provides a rationale for the assessment of JAK inhibitors (JAKi) in clinical trials with patients with axSpA. In this review, we examine the role of JAK–STAT signaling in the pathogenesis of axSpA and summarize the results from recent clinical trials of JAKi (tofacitinib, upadacitinib, and filgotinib) in patients with axSpA.

Adult-onset Still's disease or systemic-onset juvenile idiopathic arthritis and spondyloarthritis: overlapping syndrome or phenotype shift?

OBJECTIVES

Systemic-onset juvenile idiopathic arthritis (SJIA) and adult-onset Still's disease (AOSD) are the same sporadic systemic auto-inflammatory disease. Spondyloarthritis (SpA) is a group of inflammatory non-autoimmune disorders. We report the observations of eight patients with SJIA/AOSD who also presented features of SpA during their disease evolution and estimate the prevalence of SpA in SJIA/AOSD.

METHODS

This was a retrospective national survey of the departments of paediatric and adult rheumatology and internal medicine. To be included, SJIA patients had to fulfil the ILAR criteria, AOSD patients the Yamaguchi or Fautrel criteria, and all patients the ASAS classification criteria for axial or peripheral SpA, ESSG criteria for spondyloarthropathy or CASPAR criteria for psoriatic arthritis. The data were collected with a standardized form.

RESULTS

Eight patients (five adults) were identified in one paediatric and two adult departments. In all but one patient, SpA manifestations occurred several years after SJIA/AOSD onset (mean delay 6.2 ± 3.8 years). Two patients had peripheral and three axial SpA, and four later exhibited psoriatic arthritis and one SAPHO syndrome. The prevalence of SpA in an adult cohort of 76 patients with AOSD was 6.58% (95% CI [2.17-14.69]), greater than the prevalence of SpA in the French general population (0.3%, 95%CI [0.17-0.46]). The prevalence of SpA in an SJIA cohort of 30 patients was 10% (95%CI [2.11-26.53]), more than that reported in the general population of industrialized countries, estimated at 0.016% to 0.15%.

CONCLUSION

Whilst the temporal disassociation between SpA and AOSD in most cases might suggest a coincidental finding, our work raises the possibility of an SpA AOSD spectrum overlap that needs further study.

Novel Interventional Techniques for Chronic Pain with Minimally Invasive Arthrodesis of the Sacroiliac Joint: (INSITE, iFuse, Tricor, Rialto, and others)

Acute and chronic pain are public health issues that clinicians have been battling for years. Opioid medications have been a treatment option for both chronic and acute pain; however, they can cause unwanted complications and are a major contributor to our present opioid epidemic. The sacroiliac (SI) joint is a common cause of both acute and chronic low back pain. It affects about 15–25% of patients with axial low back pain, and up to 40% of patients with ongoing pain following lumbar fusion. Recent advances in the treatment of SI joint pain have led to the development of a wide variety of SI joint fusion devices. These fusion devices seek to stabilize the joints themselves in order that they become immobile and, in theory, can no longer be a source for pain. This is a minimally invasive procedure aimed to address chronic pain without subjecting patients to lengthy surgery or medications, including opioids with the potential for addiction and abuse. Minimally invasive SI fusion can be performed by a lateral approach (i.e., iFuse, Tricor) or posterior approach (i.e., CornerLoc, LinQ, Rialto). The posterior approach requires the patient to be in the prone position but allows for less disruption of muscles with entry. More data are necessary to determine which fusion system may be best for a particular patient. SI fusion devices are a promising way of treating chronic lower back pain related to the SI joint. This narrative review will discuss various types of SI fusion devices, and their potential use in terms of their safety and efficacy.

Detection of Human Leukocyte Antigen B27 by Flowcytometry in Patients With Suspected Ankylosing Spondylitis in a Tertiary Care Centre

Introduction Human leukocyte antigen B27 (HLA-B27) is strongly implicated in the pathogenesis of ankylosing spondylitis (AS). Hence, HLA-B27 testing is routinely used in the diagnosis of AS. Objectives We aimed to establish the frequency of HLA-B27 in AS patients by flow cytometry and relate the differences between B27+ and B27- cases to the serum concentrations of rheumatoid arthritis factor (RA), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Methods  The study population included a total of 210 patients who visited the tertiary health care center. The peripheral blood samples obtained from AS patients were subjected to a qualitative two-color direct immunofluorescence method using the HLA-B27/CD3 antibody for the rapid detection of HLA-B27 antigen expression in erythrocyte-lysed whole blood in FACSCalibur flow cytometer (Becton Dickinson, USA). Results Out of 210 AS patients, the distribution of HLA-B27 positivity was observed only in 46 (22%) patients. The remaining 164 patients (78.1%) were negative for HLA-B27. Of the 46 HLA positive patients, 39 (25.34%) were males and only seven (12.5%) were females. In both sexes, HLA-B27 frequency was significantly higher in the age group 21-30 years, followed by 41-50 years. The current study also revealed a significant association between sex and age of onset of HLA‑B27 detection in patients with suspected AS. Disease activity was not significantly correlated with RA, ESR, and CRP. Conclusions The detection of HLA-B27 by flow cytometry proved to be a reliable test in the screening of AS in the Indian population.

Tackling the autoimmune side in Spondyloarthritis: A systematic review

Spondyloarthritis (SpA) are a heterogeneous group of inflammatory chronic diseases characterized by sharing common pathogenic, clinical and radiologic features. The aim of this review is to support clinicians in understanding and managing this complex disease, from pathogenesis to therapeutic targets, through a systematic review of the current literature in accordance with PRISMA guidelines and checklist. HLA-B27 has been found to be associated with axial involvement either in SA and in PsA patients: it might be involved through presentation of an "arthritogenic peptide" to autoreactive CD8+ T cells or might accumulate in misfolded form and induce production pro-inflammatory cytokines by binding to several innate immune receptors. This genetic background in combination with mechanical stress leads to the activation of both innate and acquired immune responses as well as a possible role of autoimmunity in SpA pathogenesis. The release of IL-23 and IL-17 is relevant for their systemic and local effect on bone, inducing the activation of osteoclasts. Thus, the regulatory role of IL-17 on fibroblasts, osteoblasts and chondrocytes has an impact in both synovial inflammation and joint destruction. Innovative therapies targeting IL-12/23 and IL-17 and the use of small targeted synthetic molecules, as JAK-inhibitors, proved to be effective in SpA patients representing an alternative strategy to TNF-inhibitors.

Usefulness of complex bacteriological and serological analysis in patients with spondyloarthritis

Spondyloarthritis (SpA) is a group of associated chronic systemic inflammatory immune-mediated rheumatic diseases affecting axial and peripheral joints and entheses. The aim of the present study was to identify what parameters are useful to determine in order to better understand the correlation between the disease activity/severity and the microbiological results/immune status against intestinal and/or urogenital pathogens. Microorganisms known to trigger SpA, including Klebsiella spp., Yersinia spp., Salmonella spp., Campylobacter spp. and Chlamydia spp., were analyzed in various specimens (stool, urine, synovial fluid and serum) collected from 27 randomly selected SpA patients and 26 healthy controls using a combined direct and indirect approach relying on conventional culture technique and nucleic acid-based assays together with serological testing by ELISA. Although Escherichia coli derived from phylogroup A prevailed in the gut microflora of the patients and controls, differences were observed regarding the representatives of the other phylogroups with a higher prevalence of E.coli members of phylogenetic group B1 in the stool specimens of patients. Antibodies against the targeted species were detected in SpA patients and controls, and the serological profiles of the former were more diverse and complex. In conclusion, the detection of anti-bacterial antibodies combined with other specific laboratory investigations should be more extensively used to monitor SpA patients in association with their symptoms and in order to determine and administer more effective therapeutics.

Clinical and Radiological Assessment in Axial Spondyloarthritis

The Assessment of SpondyloArthritis International Society (ASAS) has developed the concept of axial spondyloarthritis (SpA) in 2009. The symptoms and burden of disease of nonradiographic axial SpA and Ankylosing Spondylitis (AS) are similar and both can affect multiple organs and systems. Assessment and monitoring in SpA are, therefore, crucial. Different instruments have been developed for assessing and monitoring the wide variety of presentations in SpA. Generally, disease monitoring of patients can include patient reported outcome, clinical findings, laboratory tests, imaging, and disease activity composite scores.

Interethnic Variations and Clinical Features of Spondyloarthropathies in a Middle Eastern Country

Objectives

The study aimed to demonstrate the interethnic differences and clinical features of Spondyloarthropathy(SpA) patients in a diverse Middle Eastern Country.

Methods

A retrospective review of medical records to collect the required data was conducted for SpA patients at two study institutions in the United Arab Emirates.

Results

Of 141 SpA patients found, 88 AS(Ankylosing Spondylitis) patients and 53 'other SpA' patients were identified. Males constituted 81% of AS and 55% of 'other SpA' patients. Patients with AS and 'other SpA' had a mean age of symptom onset of 28 and 34 years, respectively.49% and 40% of AS and 'other SpA' patients had a history of Anti-TNF therapy usage. Enthesitis and Uveitis were noted in 16% and 18% of AS patients whilst 53% and 11% in 'other SpA' patients, respectively.Caucasian, Indian Subcontinent and Arabs constituted 93% of our cohort. Mean age of onset of symptoms in the Indian Subcontinent 'other SpA' group was much greater than the other two ethnicities. Duration of symptoms to diagnosis was 3.5 and 4 years in AS and other SpA patients' respectively. HLA-B27 positivity was found in 53%, 80% and 93% of Arab, Indian Subcontinent and Caucasian AS patients, respectively, whilst seen in 50%, 25% and 33% of the same respective ethnicties in 'other SpA' patients.

Conclusion

This study on 141 patients is the largest to analyse inter-ethnic variations in SpA patients in the region. Our cohort shows a short delay in diagnosis with a relatively higher Anti-TNF usage.

Progress of genome-wide association studies of ankylosing spondylitis

Ankylosing spondylitis (AS) is an immune-mediated arthritis which primarily affects the spine and sacroiliac joints. Significant progress has been made in discovery of genetic associations with AS by genome-wide association studies (GWAS) over past decade. These findings have uncovered novel pathways involved pathogenesis of the disease and have led to introduction of novel therapeutic treatments for AS. In this Review, we discuss the genetic variations associated with AS identified by GWAS, the major pathways revealed by these AS-associated variations and critical cell types involved in AS development.

Discovery of T Cell Receptor β Motifs Specific to HLA-B27-Positive Ankylosing Spondylitis by Deep Repertoire Sequence Analysis

OBJECTIVE

Ankylosing spondylitis (AS), a chronic inflammatory disorder, has a notable association with HLA-B27. One hypothesis suggests that a common antigen that binds to HLA-B27 is important for AS disease pathogenesis. This study was undertaken to determine sequences and motifs that are shared among HLA-B27-positive AS patients, using T cell repertoire next-generation sequencing.

METHODS

To identify motifs enriched among B27-positive AS patients, we performed T cell receptor β (TCRβ) repertoire sequencing on samples from 191 B27-positive AS patients, 43 B27-negative AS patients, and 227 controls, and we obtained >77 million TCRβ clonotype sequences. First, we assessed whether any of 50 previously published sequences were enriched in B27-positive AS patients. We then used training and test cohorts to identify discovered motifs that were enriched in B27-positive AS patients versus controls.

RESULTS

Six previously published and 11 discovered motifs were enriched in the B27-positive AS samples as compared to controls. After combining motifs related by sequence, we identified a total of 15 independent motifs. Both the full set of 15 motifs and a set of 6 published motifs were enriched in the B27-positive AS patients as compared to B27-positive healthy individuals (P = 0.049 and P = 0.001, respectively). Using an independent cohort, we validated that at least some of these motifs were associated with AS, and not simply with B27-positive status.

CONCLUSION

We identified TCRβ motifs that are enriched in B27-positive AS patients as compared to B27-positive healthy controls. This suggests that a common antigen, presented by HLA-B27 and detected by CD8+ T cells, may be associated with AS disease pathogenesis.

Detection of novel diagnostic antibodies in ankylosing spondylitis: An overview

Ankylosing spondylitis (AS) is a debilitating, chronic, rheumatic disease characterized by inflammation and new bone formation resulting in fusion of the spine and sacroiliac joints. Since early treatment is impeded by a delayed diagnosis, it is highly important to find new biomarkers that improve early diagnosis and may also contribute to a better assessment of disease activity, prognosis and therapy response in AS. Because of the absence of rheumatoid factor, AS was long assumed to have a seronegative character and antibodies are thus not considered a hallmark of the disease. However, emerging evidence suggests plasma cells and autoantibodies to be involved in the disease course. In this review, the role of B cells and antibodies in AS is discussed. Furthermore, an overview is provided of antibodies identified in AS up till now, and their diagnostic potential. Many of these antibody responses were based on small study populations and further validation is lacking. Moreover, most were identified by a hypothesis-driven approach and thus limited to antibodies against targets that are already known to be involved in AS pathogenesis. Hence, we propose an unbiased approach to identify novel diagnostic antibodies. The already successfully applied techniques cDNA phage display and serological antigen selection will be used to identify antibodies against both known and new antigen targets in AS plasma. These newly identified antibodies will enhance early diagnosis of AS and provide more insight into the underlying disease pathology, resulting in a more effective treatment strategy and eventually an improved disease outcome.

Association between bone turnover markers, clinical variables, spinal syndesmophytes and bone mineral density in Mexican patients with ankylosing spondylitis

OBJECTIVES

To compare bone turnover marker (BTM) levels and bone mineral density (BMD) between patients with ankylosing spondylitis (AS) and healthy controls (HC) and to evaluate, in AS, the association between BTM levels and clinical variables, spinal syndesmophytes, and BMD using multivariate analysis.

METHOD

Seventy-eight AS patients were compared with 58 HC matched by gender. Spinal syndesmophytes in AS and other characteristics were assessed. C-terminal telopeptide fragments of type I collagen (CTX), bone-specific alkaline phosphatase (BAP), osteocalcin (OC) serum levels, and BMD of the lumbar spine, femoral neck, and forearm were evaluated.

RESULTS

AS males and females had lower BAP levels than their respective HC (p < 0.001 and p = 0.001). AS patients with bridging syndesmophytes had higher OC levels than AS patients either with non-bridging syndesmophytes (p = 0.001) or without spinal syndesmophytes (p < 0.001). OC and CTX levels correlated significantly with the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). In the multivariate linear regression adjusted by age, gender, the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), BMD in the lumbar spine, and C-reactive protein (CRP), we observed an association between BAP levels and anti-tumour necrosis factor (anti-TNF) use (p = 0.05) whereas OC levels were associated with mSASSS (p < 0.001) and anti-TNF use (p = 0.05), and CTX levels were exclusively associated with mSASSS (p = 0.03). In the logistic regression analysis, only OC levels were associated with the presence of syndesmophytes in AS [odds ratio (OR) 2.42, 95% confidence interval (CI) 1.19-5.75].

CONCLUSIONS

We observed an increase in OC levels in AS patients with syndesmophytes. BTM levels were associated with the severity of spinal damage. Future longitudinal studies should evaluate whether these BTMs should be included as tools to determine the prognosis and progression of spinal damage.

Sulfasalazine Treatment Suppresses the Formation of HLA-B27 Heavy Chain Homodimer in Patients with Ankylosing Spondylitis

Human leukocytic antigen-B27 heavy chain (HLA-B27 HC) has the tendency to fold slowly, in turn gradually forming a homodimer, (B27-HC)₂ via a disulfide linkage to activate killer cells and T-helper 17 cells and inducing endoplasmic reticulum (ER) stress to trigger the IL-23/IL-17 axis for pro-inflammatory reactions. All these consequences lead to the pathogenesis of ankylosing spondylitis (AS). Sulfasalazine (SSA) is a common medication used for treatment of patients with AS. However, the effects of SSA treatment on (B27-HC)₂ formation and on suppression of IL-23/IL-17 axis of AS patients remain to be determined. In the current study, we examine the (B27-HC)₂ of peripheral blood mononuclear cells (PBMC), the mean grade of sarcoiliitis and lumbar spine Bath Ankylosing Spondylitis Radiology Index (BASRI) scores of 23 AS patients. The results indicated that AS patients without (B27-HC)₂ on PBMC showed the lower levels of mean grade of sarcoiliitis and the lumbar spine BASRI scores. In addition, after treatment with SSA for four months, the levels of (B27-HC)₂ on PBMCs were significantly reduced. Cytokines mRNA levels, including TNFα, IL-17A, IL-17F and IFNγ, were also significantly down-regulated in PBMCs. However, SSA treatment did not affect the levels of IL-23 and IL-23R mRNAs.

Chronic Periodontitis Is Associated With Spinal Dysmobility in Patients With Ankylosing Spondylitis

BACKGROUND

Although microbes have been suggested to play a role in the pathogenesis of ankylosing spondylitis (AS), several studies present contradictory results regarding the association between AS and chronic periodontitis (CP).

METHODS

Clinical, laboratory, and medication data were collected from 84 patients with AS and 84 age- and sex-matched controls. Periodontal measurements, including probing depths (PDs), clinical attachment loss (AL), serum anti-Porphyromonas gingivalis titers, and the detection of P. gingivalis DNA in gingival crevicular fluid, were recorded. All participants with periodontitis with PD ≥4 to <7 mm received scaling and root planing and were re-evaluated at 12 weeks; those still exhibiting periodontitis with PD of ≥4 to <7 mm at 12 weeks were followed at 24 weeks.

RESULTS

The prevalence of moderate-to-severe CP was not different between patients with AS and controls (70.2% versus 66.6%). The P. gingivalis detection rate was not different between patients with AS and controls or between patients with AS receiving and not receiving anti-tumor necrosis factor (TNF)-α agents. However, CP was positively associated with impaired spinal mobility of patients with AS in multivariate analyses. After periodontal treatment, PD and AL levels were improved in both groups, but the change was significantly greater in patients with AS than in controls. Patients with AS receiving anti-TNF-α agents exhibited a greater improvement in PD and AL than those who did not.

CONCLUSIONS

Although AS was not associated with the presence of CP, CP was associated positively with the severity of spinal dysmobility in Korean patients with AS. These results suggest that periodontitis can have a negative effect on axial movement in AS.

Gait characteristics associated with the foot and ankle in inflammatory arthritis: a systematic review and meta-analysis

BACKGROUND

Gait analysis is increasingly being used to characterise dysfunction of the lower limb and foot in people with inflammatory arthritis (IA). The aim of the systematic review was to evaluate the spatiotemporal, foot and ankle kinematic, kinetic, peak plantar pressure and muscle activity parameters between patients with inflammatory arthritis and healthy controls.

METHODS

An electronic literature search was performed on Medline, CINAHL, SportsDiscus and The Cochrane Library. Methodological quality was assessed using a modified Quality Index. Effect sizes with 95% confidence intervals (CI) were calculated as the standardised mean difference (SMD). Meta-analysis was conducted if studies were homogenous.

RESULTS

Thirty six studies with quality ranging from high to low met the inclusion criteria. The majority of studies reported gait parameters in Rheumatoid arthritis (RA). The gait pattern in RA was characterised by decreased walking speed (SMD 95% CI -1.57, -2.25 to -0.89), decreased cadence (SMD -0.97, -1.49 to -0.45), decreased stride length (SMD -1.66, -1.84 to -1.49), decreased ankle power (SMD -1.36, -1.70 to -1.02), increased double limb support time (SMD 1.03, 0.84 to 1.22), and peak plantar pressures at the forefoot (SMD 1.11, 0.76 to 1.45). Walking velocity was reduced in psoriatic arthritis and gout with no differences in ankylosing spondylitis. No studies have been conducted in polymyalgia rheumatica, systemic sclerosis or systemic lupus erythematosus.

CONCLUSIONS

The review identified the majority of studies reporting gait adaptations in RA, but limited evidence relating to other IA conditions. Poor data reporting, small sample sizes and heterogeneity across IA conditions limit the interpretation of the findings. Future studies may consider a standardised analytical approach to gait analysis that will provide clinicians and researchers with objective evidence of foot function in people with IA.

Pain in systemic inflammatory rheumatic diseases

The sometimes intense, persistent and disabling pain associated with rheumatoid arthritis (RA) and spondyloarthritis frequently has a multifactorial, simultaneously central and peripheral origin, and it may be due to currently active inflammation or joint damage and tissue destruction caused by a previous inflammatory condition. The symptoms of inflammatory pain symptoms can be partially relieved by non-steroidal anti-inflammatory drugs, but many patients continue to experience moderate pain due to alterations in central pain regulation mechanisms, as in the case of the chronic widespread pain (CWP) characterising fibromyalgia. The importance of distinguishing CWP from inflammatory pain is underlined by the fact that drugs such as tumour necrosis factor inhibitors are expensive, and direct costs are higher in patients with concomitant CWP than in those without. The management of pain requires a combination approach that includes pharmacological analgesia, and biological and non-biological treatments because, although joint replacement surgery can significantly improve RA-related pain, it may only be available to patients with the most severe advanced disease.

The risk of asthma in patients with ankylosing spondylitis: a population-based cohort study

Background

The relationship between asthma and ankylosing spondylitis (AS) is controversial. We examined the risk of asthma among AS patients in a nationwide population.

Methods

We conducted a retrospective cohort study using data from the National Health Insurance (NHI) system of Taiwan. The cohort included 5,974 patients newly diagnosed with AS from 2000 to 2010. The date of diagnosis was defined as the index date. A 4-fold of general population without AS was randomly selected frequency matched by age, gender and the index year. The occurrence and hazard ratio (HR) of asthma were estimated by the end of 2011.

Results

The overall incidence of asthma was 1.74 folds greater in the AS cohort than in the non-AS cohort (8.26 versus 4.74 per 1000 person-years) with a multivariable Cox method measured adjusted HR of 1.54 (95% confidence interval (CI), 1.34–1.76). The adjusted HR of asthma associated with AS was higher in women (1.59; 95% CI, 1.33–1.90), those aged 50–64 years (1.66; 95% CI, 1.31–2.09), or those without comorbidities (1.82; 95% CI, 1.54–2.13).

Conclusion

Patients with AS are at a higher risk of developing asthma than the general population, regardless of gender and age. The pathophysiology needs further investigation.

Ankylosing spondylitis: from cells to genes

Ankylosing spondylitis (AS) is a chronic inflammatory disease of unknown etiology, though it is considered an autoimmune disease. HLA-B27 is the risk factor most often associated with AS, and although the mechanism of involvement is unclear, the subtypes and other features of the relationship between HLA-B27 and AS have been studied for years. Additionally, the key role of IL-17 and Th17 cells in autoimmunity and inflammation suggests that the latter and the cytokines involved in their generation could play a role in the pathogenesis of this disease. Recent studies have described the sources of IL-17 and IL-23, as well as the characterization of Th17 cells in autoimmune diseases. Other cells, such as NK and regulatory T cells, have been implicated in autoimmunity and have been evaluated to ascertain their possible role in AS. Moreover, several polymorphisms, mutations and deletions in the regulatory proteins, protein-coding regions, and promoter regions of different genes involved in immune responses have been discovered and evaluated for possible genetic linkages to AS. In this review, we analyze the features of HLA-B27 and the suggested mechanisms of its involvement in AS while also focusing on the characterization of the immune response and the identification of genes associated with AS.

Immunotherapeutic implication of IL-6 blockade

IL-6 is a cytokine featuring redundancy and pleiotropic activity. While IL-6 contributes to host defense against acute environmental stress, continuous IL-6 production plays a significant pathological role in various autoimmune and chronic inflammatory diseases. To counter this drawback, tocilizumab, a humanized anti-IL-6 receptor antibody, was developed. Clinical trials have verified the efficacy of tocilizumab for patients with rheumatoid arthritis, Castleman's disease and systemic juvenile idiopathic arthritis, resulting in approval of this innovative biologic for their treatment. Moreover, a considerable number of case reports and pilot studies have indicated the beneficial effects of tocilizumab on other autoimmune and chronic inflammatory diseases. Further clinical studies to evaluate the efficacy and safety of tocilizumab for these diseases are essential.

Distribution of HLA class I and II genes in ankylosing spondylitis patients from Morocco

OBJECTIVES

In Morocco, the patients affected by ankylosing spondylitis (AS) presents a high frequency of coxitis. Our study reports, for the first time, the polymorphism of Human Leukocyte Antigen (HLA) class I and class II molecules in the Moroccan patients.

METHODS

Forty-six patients diagnosed with an AS and coxitis were compared to a group of 183 healthy controls matched by age, sex and ethnic origin. The HLA typing was performed using microlymphocytotoxicity for the class I (-A, -B) and PCR-SSP for the class II (-DR, -DQ).

RESULTS

We found a significant increase of the HLA-B27 antigen frequency (P<0.0001, RR=20.9) in AS patients (29.3%) compared to the controls (3.2%) and a significant decrease in the frequency of HLA-B12 and HLA-B18 antigens. Examination of HLA class II distribution shows a significant increase of the HLA-DRB1*11 allele frequency in patients (P<0.0001). Concerning HLA-DQB1* alleles, no significant difference between patients and controls was appreciable.

CONCLUSIONS

The HLA-B27 antigen is involved in the predisposition to the AS with coxitis in the Moroccan population. However, the low frequency observed in our population suggests the existence of other genetic and/or environmental factors. Other HLA genes seem to confer a predisposing effect (DRB*11) or a protective effect (B12 and B18) against the disease.

Spondyloarthropathies in autoimmune diseases and vice versa

Polyautoimmunity is one of the major clinical characteristics of autoimmune diseases (ADs). The aim of this study was to investigate the prevalence of ADs in spondyloarthropathies (SpAs) and vice versa. This was a two-phase cross-sectional study. First, we examined the presence of ADs in a cohort of patients with SpAs (N = 148). Second, we searched for the presence of SpAs in a well-defined group of patients with ADs (N = 1077) including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and Sjögren's syndrome (SS). Among patients with SpAs, ankylosing spondylitis was observed in the majority of them (55.6%). There were two patients presenting with SS in the SpA group (1.4%) and 5 patients with autoimmune thyroiditis (3.5%). The global prevalence of ADs in SpAs was 4.86%. In the ADs group, there were 5 patients with SpAs (0.46%). Our results suggest a lack of association between SpAs and ADs. Accordingly, SpAs might correspond more to autoinflammatory diseases rather than to ADs.

Therapeutic targeting of the interleukin-6 receptor

Interleukin (IL)-6 is a typical cytokine featuring redundancy and pleiotropic activity. It contributes to host defense against pathogens, but dysregulation of IL-6 production plays a significant pathological role in various autoimmune and inflammatory diseases. Because IL-6 blockade was expected to constitute a novel strategy for the treatment of such diseases, tocilizumab, a humanized anti-IL-6 receptor antibody (anti-IL-6RAb), was developed. Clinical trials have demonstrated the efficacy of anti-IL-6RAb for patients with rheumatoid arthritis, Castleman's disease, and juvenile idiopathic arthritis, resulting in approval of this innovative biologic for the treatment of these diseases, and it can be expected to become a novel drug for various other autoimmune and inflammatory diseases. In murine models of autoimmune diseases, anti-IL-6RAb induces Treg and inhibits Th17 and/or Th1 differentiation, indicating that anti-IL-6RAb may be able to repair Th17/Treg imbalance in human diseases as well.

Combination antibiotics for the treatment of Chlamydia-induced reactive arthritis: is a cure in sight?

The inflammatory arthritis that develops in some patients subsequent to urogenital infection by the obligate intracellular bacterial pathogen Chlamydia trachomatis, and that induced subsequent to pulmonary infection with C. pneumoniae, both have proved difficult to treat in either their acute or chronic forms. Over the last two decades, molecular genetic and other studies of these pathogens have provided a good deal of information regarding their metabolic and genetic structures, as well as the detailed means by which they interact with their host cells. In turn, these insights have provided for the first time a window into the bases for treatment failures for the inflammatory arthritis. In this article we discuss the biological bases for those treatment failures, provide suggestions as to research directions that should allow improvement in treatment modalities, and speculate on how treatment regimens that currently show promise might be significantly improved over the near future using nanotechological means.

Anti-interleukin-6 receptor antibody, tocilizumab, for the treatment of autoimmune diseases

Interleukin (IL)-6 is a cytokine with multiple biological activities. It contributes to host defense against pathogens, whereas accelerated production of IL-6 plays a significant pathological role in various diseases. Clinical trials have demonstrated the efficacy of tocilizumab, a humanized anti-IL-6 receptor antibody, for patients with rheumatoid arthritis, Castleman's disease or juvenile idiopathic arthritis, leading to approval of this innovative drug for the treatment of these diseases. Since IL-6 has been demonstrated to play a significant role in the development of various other autoimmune and inflammatory diseases, tocilizumab can be expected to become a novel drug for such diseases as well.

Association and frequency of HLA-A, B and HLA-DR genes in south Tunisian patients with spondyloarthritis (SpA)

The aim of this study is to investigate the association of HLA-A, B and HLA-DR gene expression and to assess an association of additional HLA antigens besides HLA-B27 in south Tunisian patients with spondyloarthritis (SpA). Eighty-five patients diagnosed with ankylosing spondylitis (AS, n=68) and reactive arthrithis (ReA, n=17) were selected and compared with 100 healthy controls (HC). HLA class I antigens were typed serologically using microlymphocytotoxicity technique. HLA-DRB1* alleles were studied by polymerase chain reaction amplification with sequence-specific primers. The significance of differences between patients and controls was tested by chi-square analysis. We found significantly increased frequencies of HLA-A3 (30.6%; pC=0.04; OR=2.95), HLA-B27 (62.35%; pC=4.10(-17), OR=53.55), and HLA-DRB1*15 (17.2%; pC=0.026; RR=2.58) alleles in SpA patients compared to HC. The most frequent and strongest association was observed for HLA-B27 in AS (pC=6.6 ×10(-16), OR=52.23). When AS and ReA patients were analysed separately, HLA-DRB1*15 and HLA-A3 were increased only in AS (pC=0.01, OR=2.99 and pC=0.03, OR=3.14, respectively). In ReA patients, HLA-DRB1*04 (p=0.033, pC=NS, OR=2.89) was found to be the most common allele. By analysing the HLA-B27-negative subgroup, HLA-A3 and HLA-DRB1*15 expression was found to be dependent on the presence of HLA-B27. HLA-B27 expression was higher in male (45/53; 85%) as compared to female (8/53; 15%) patients (p=0.03). Apart from HLA-B27, HLA-A3 and HLA-DRB1*15 are the MHC class I and II alleles found most frequent in Tunisian patients with AS, whereas HLA-DRB1*04 was found most frequent in ReA patients. HLA-B27 is more frequent in male than in female patients.

[Reactive arthritis: from pathogenesis to novel strategies]

Reactive arthritis (ReA) was first described 100 years ago. It is defined as a sterile joint inflammation following a primary, extra-articular infection often in the form of urethritis or enteritis and less frequently respiratory infection and is characterized by the presence of bacterial antigens or non-culturable bacteria in the joint,. The prevalence is estimated to be 40/100,000 adults, while the incidence is 4-5/100,000. The classic HLA-B27-associated form with asymmetric involvement of the lower extremities and/or the spine is part of the spondyloarthritis concept. The phenomenon of persistence, which will be discussed in detail herein, plays an important role in the pathogenesis of ReA. Up to 30% of patients develop chronic symptoms posing a therapeutic challenge. Combination antibiotic treatment showing a response in up to 63% of patients has recently been proposed. Biologics could represent an alternative therapeutic option for patients showing a severe and highly active disease course.

Symptomatic noncompressive motoromyelopathy presents as early manifestation in ankylosing spondylitis

Ankylosing spondylitis (AS) is an autoimmune spondyloarthropathy involving principally the sacroiliac joint and axial skeleton. Spinal cord involvement is an infrequent and late complication. It mostly results from compressive myelopathy due to skeletal osteopathy and usually presents with radiculomyelopathic sensory and motor deficits. To report three patients who suffered a progressive paraparesis/tetraparesis compatible with motor myelopathy without typical skeletal symptom. Myelopathy of unknown origin was initially interpreted in these patients. Radiography did not show typical change at sacroiliac joint or vertebrate. Spinal magnetic resonance image revealed cord atrophy at cervical and thoracic segment. A positivity of B27 antigen was found afterward. Their spondyloarthropathic symptoms developed within six months later with radiographic sacroiliitis. Seropositive AS with noncompressive myelopathy was finally established. Patients showed a reverse of motor impairment when their pain was well undercontrolled. Motor myelopathy may be neglected or underestimated in AS, in especially when typical skeletal symptom is absent or minimal. It may progress surreptitiously to harm spinal function or superimpose to crippling disability in compressive spinal cord injury. Therefore, a careful evaluation and monitor of spinal cord function is important for AS patient despite spinal deformity is not observed.

Differences between juvenile-onset ankylosing spondylitis and adult-onset ankylosing spondylitis

BACKGROUND

Ankylosing spondylitis (AS) is a chronic inflammatory disease, which involves the spine, peripheral joints and entheses. Juvenile-onset ankylosing spondylitis (JAS) affects children under the age of 16 years. JAS has been noted to present as clinical courses different from those of adult-onset ankylosing spondylitis (AAS). Therefore, the purpose of the present study was to compare the possible risk factors, clinical manifestations, laboratory markers, radiological changes, and functional outcome between these 2 patient groups.

METHODS

AS patients were enrolled from the rheumatologic clinic of a tertiary medical center from January 1 to June 30 in 2006. The demographic data, clinical symptoms/signs, Bath AS indices, HLA-B27, inflammatory markers, radiological findings, and treatment history were acquired with questionnaires, clinical evaluation, and chart review. The differences between JAS and AAS patients were evaluated and analyzed.

RESULTS

A total of 169 patients (142 males, 27 females) were included, comprising 47 JAS and 122 AAS patients. The ages of onset were 12.8 +/- 2.7 years and 25.0 +/- 7.4 years for JAS and AAS, respectively. They had similar gender distribution, years of delay to diagnosis and disease duration. A substantial proportion of our patients (40.4% of JAS and 34.4% of AAS) had physical trauma in the 1 month before disease onset. Also, 22.7% of JAS patients had intense physical training, while 25.2% of AAS patients did heavy work during the period. The first manifestation of JAS was mainly peripheral enthesopathy or arthritis, but axial symptoms in most AAS. More JAS patients had peripheral enthesopathies and arthritis on any occasion. Although there was a trend of higher score in Bath AS Disease Activity Index (BASDAI), Bath AS Metrology Index (BASMI) and Physician's Global Assessment (PGA) score, JAS patients had a comparable Bath AS Functional Index (BASFI) and Bath AS Patient's Global Assessment (BAS-G) as AAS patients. As to the laboratory and radiological tests, JAS patients had higher levels of C-reactive protein and erythrocyte sedimentation rate, and more radiographic changes of hip joints.

CONCLUSION

JAS and AAS patients had distinct presentations. JAS presented more peripheral enthesopathies and arthritis at disease onset and at any time of the course. If treated effectively, JAS will not lead to a worse functional outcome than AAS. Therefore, it is mandatory to diagnose and treat JAS as early as possible.

Role of Klebsiella and collagens in Crohn's disease: a new prospect in the use of low-starch diet

Crohn's disease is suggested to result from a microbially triggered immune-mediated autoimmune process, involving mainly the terminal ileum and ileo-caecal junction. Klebsiella pneumoniae shares certain molecular structures present in pullulanase pulA and pulD secretion enzymes with various self-antigens present in collagens and HLA-B27 molecules, respectively. A link exists between high dietary starch intake and the growth of intestinal microflora, involving especially Klebsiella microbes. Increased exposure to Klebsiella in the gut as the result of high starch intake would lead to high production of antiKlebsiella antibodies as well as autoantibodies to the cross-reactive self-antigens with the resultant inflammation at the pathological sites. Eradication of these microbes from the gut in patients with Crohn's disease with the use of low-starch diet and antibacterial agents as well as immunomodulatory measures could be beneficial in the management of this disease.

Ankylosing enthesitis associated with up-regulated IFN-gamma and IL-17 production in (BXSB x NZB) F(1) male mice: a new mouse model

We found that in contrast to (BXSB x NZB) F(1) female mice that spontaneously develop severe systemic lupus erythematosus (SLE), male (BXSB x NZB) F(1) mice are not prone to SLE, but instead develop seronegative ankylosing enthesitis in ankle/tarsal joints only when caged in groups, with the incidence reaching 83% at 7 months of age. This ankylosis is microscopically characterized by a marked proliferation of fibroblast-like cells positive for bone morphogenetic protein (BMP)-2 in association with heterotropic formation of cartilages and bones in hyperplastic entheseal tissues and subsequent fusion of tarsal bones. Elevated potentials of popliteal lymph node T cells producing interleukin (IL)-17 and interferon (IFN)-gamma were significantly associated with joint ankylosis, suggesting the involvement of these cytokines in effector phase mechanisms of the disease, including up-regulated BMP signaling pathways. There was no difference in serum autoantibody levels between affected and unaffected mice. Parental BXSB and NZB strains of both sexes did not develop the disease even when caged in groups, indicating that the disease develops under the control of susceptibility genes derived from both parental strains. These results indicate that (BXSB x NZB) F(1) male mice are a suitable model for clarifying genetic, environmental and molecular mechanisms underlying ankylosing enthesitis and related diseases.

Spondyloarthritis: clinical suspicion, diagnosis, and sports

Spondyloarthritis (SpA), a family of inflammatory back diseases including ankylosing spondylitis, is an important and under-recognized cause of chronic back pain in younger patients who are likely to participate in sports and athletic activities. These diseases are characterized by the presence of inflammatory back pain--lumbar or buttock/hip pain lasting longer than 3 months associated with improvement with activity, worsening with rest, relief with non-steroidal anti-inflammatory drugs (NSAIDs), and morning stiffness lasting longer than 30 min. There are also characteristic radiographic findings involving the sacroiliac joints, vertebrae, and in certain diseases, the peripheral joints. Exercise has long been recognized as a key component of the therapy of SpA, yielding benefits in mobility, pain, stiffness, functionality, and depression. Sports also pose a risk to patients with SpA as these patients are at high risk of spinal fracture and spinal cord injury.

Recent advances in the genetics of autoimmune disease

Extraordinary technical advances in the field of human genetics over the past few years have catalyzed an explosion of new information about the genetics of human autoimmunity. In particular, the ability to scan the entire genome for common polymorphisms that associate with disease has led to the identification of numerous new risk genes involved in autoimmune phenotypes. Several themes are emerging. Autoimmune disorders have a complex genetic basis; multiple genes contribute to disease risk, each with generally modest effects independently. In addition, it is now clear that common genes underlie multiple autoimmune disorders. There is also heterogeneity among subphenotypes within a disease and across major racial groups. The current crop of genetic associations are only the start of a complete catalog of genetic factors for autoimmunity, and it remains unclear to what extent common variation versus multiple rare variants contribute to disease susceptibility. The current review focuses on recent discoveries within functionally related groups of genes that provide clues to novel pathways of pathogenesis for human autoimmunity.