Inflammatory bowel disease serologies in ankylosing spondylitis patients: a pilot study

Elevated Calprotectin Levels Reveal Loss of Vascular Pattern and Atrophy of Villi in Ileum by Digital Chromoendoscopy and Magnification Colonoscopy in Patients with Spondyloarthritis Without Having Inflammatory Bowel Disease

OBJECTIVE

This study aimed to establish a correlation between fecal calprotectin levels (FC) and intestinal inflammation in patients with spondyloarthritis without inflammatory bowel disease.

METHODS

A total of 180 SpA patients were included in the study of them 20.6% required Digital chromoendoscopy (DCE). FC, C-reactive protein (CRP), HLA-B*27 and clinical indices were assessed.

RESULTS

Positive fecal calprotectin (PFC) and high fecal calprotectin (HFC) levels were observed in 27.0% and 16.0% of patients, respectively. HFC correlated with a Bath Ankylosing Spondylitis Functional Index (BASFI) score > 4.0 (p = 0.036) and a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score > 4.0 (p = 0.047). Loss of vascular pattern in the ileum (LVPI) was observed in approximately 70.0% of patients (p = 0.005), which was associated with PFC and abdominal bloating (p = 0.020). LVPI was also linked to microscopic inflammation (p = 0.012) and PFC with abdominal pain (p = 0.007). HFC was significantly associated with alterations in the ileal mucosa (p = 0.009) and LVPI (p = 0.001). Additionally, HFC and diarrhea were associated with LVPI in 27.3% of patients (p = 0.037) and with erosions in the ileum (p = 0.031). Chronic ileal inflammation correlated with HFC (p = 0.015), ASDAS-CRP > 2.1 (p = 0.09), LVPI (p = 0.001), and villous atrophy (p = 0.014). Factorial analysis of mixed data (FAMD) identified significant associations between micro/macroscopic changes in chronic inflammation and HFC (CC = 0.837); increased levels of CRP and microscopic acute inflammation (CC = 0.792); and clinical activity scores of ASDAS-CRP and BASDAI (CC = 0.914).

CONLUSIONS

FC levels were significantly elevated in patients with SpA, particularly those with LVPI, suggesting their potential as a valuable biomarker for managing SpA when joint manifestations coincide with ileal villous atrophy. This indicates a shared immune pathway linked to chronic gut damage.

Comprehensive Association Analyses of Extraintestinal Manifestations in Inflammatory Bowel Disease

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) frequently develop extraintestinal manifestations (EIMs) that contribute substantially to morbidity. We assembled the largest multicohort data set to date to investigate the clinical, serologic, and genetic factors associated with EIM complications in IBD.

METHODS

Data were available in 12,083 unrelated European ancestry IBD cases with presence or absence of EIMs (eg, ankylosing spondylitis [ankylosing spondylitis and sacroiliitis], primary sclerosing cholangitis [PSC], peripheral arthritis, and skin and ocular manifestations) across 4 cohorts (Cedars-Sinai Medical Center, National Institute for Diabetes and Digestive and Kidney Diseases IBD Genetics Consortium, Sinai Helmsley Alliance for Research Excellence Consortium, and Risk Stratification and Identification of Immunogenetic and Microbial Markers of Rapid Disease Progression in Children with Crohn's Disease cohort). Clinical and serologic parameters were analyzed by means of univariable and multivariable regression analyses using a mixed-effects model. Within-case logistic regression was performed to assess genetic associations.

RESULTS

Most EIMs occurred more commonly in female subjects (overall EIM: P = 9.0E-05, odds ratio [OR], 1.2; 95% CI, 1.1-1.4), with CD (especially colonic disease location; P = 9.8E-09, OR, 1.7; 95% CI, 1.4-2.0), and in subjects who required surgery (both CD and UC; P = 3.6E-19, OR, 1.7; 95% CI, 1.5-1.9). Smoking increased risk of EIMs except for PSC, where there was a "protective" effect. Multiple serologic associations were observed, including with PSC (anti-nuclear cytoplasmic antibody; IgG and IgA, anti-Saccharomyces cerevisiae antibodies; and anti-flagellin) and any EIM (anti-nuclear cytoplasmic antibody; IgG and IgA, anti-Saccharomyces cerevisiae antibodies; and anti-Pseudomonas fluorescens-associated sequence). We identified genome-wide significant associations within major histocompatibility complex (ankylosing spondylitis and sacroiliitis, P = 1.4E-15; OR, 2.5; 95% CI, 2.0-3.1; PSC, P = 2.7E-10; OR, 2.8; 95% CI, 2.0-3.8; ocular, P = 2E-08, OR, 3.6; 95% CI, 2.3-5.6; and overall EIM, P = 8.4E-09; OR, 2.2; 95% CI, 1.7-2.9) and CPEB4 (skin, P = 2.7E-08; OR, 1.5; 95% CI, 1.3-1.8). Genetic associations implicated tumor necrosis factor, JAK-STAT, and IL6 as potential targets for EIMs. Contrary to previous reports, only 2% of our subjects had multiple EIMs and most co-occurrences were negatively correlated.

CONCLUSIONS

We have identified demographic, clinical, and genetic associations with EIMs that revealed underlying mechanisms and implicated novel and existing drug targets-important steps toward a more personalized approach to IBD management.

Serum biomarkers and their relationship to axial spondyloarthritis associated with inflammatory bowel diseases

Spondyloarthritis (SpA) constitute a group of chronic inflammatory immune-mediated rheumatic diseases characterized by genetic, clinical, and radiological features. Recent efforts have concentrated on identifying biomarkers linked to axial SpA associated with inflammatory bowel disease (IBD), offering predictive insights into disease onset, activity, and progression. Genetically, the significance of the HLA-B27 antigen is notably diminished in ankylosing spondylitis (AS) associated with IBD, but is heightened in concurrent sacroiliitis. Similarly, certain polymorphisms of endoplasmic reticulum aminopeptidase (ERAP-1) appear to be involved. Carriage of variant NOD2/CARD15 polymorphisms has been demonstrated to correlate with the risk of subclinical intestinal inflammation in AS. Biomarkers indicative of pro-inflammatory activity, including C-reactive protein (CRP) along with erythrocyte sedimentation rate (ESR), are among the consistent predictive biomarkers of disease progression. Nevertheless, these markers are not without limitations and exhibit relatively low sensitivity. Other promising markers encompass IL-6, serum calprotectin (s-CLP), serum amyloid (SAA), as well as biomarkers regulating bone formation such as metalloproteinase-3 (MMP-3) and Dickkopf-related protein 1 (DKK-1). Additional candidate indicators of structural changes in SpA patients include matrix metalloproteinase-3 (MMP-3), vascular endothelial growth factor (VEGF), tenascin C (TNC), and CD74 IgG. Fecal caprotein (f-CLP) levels over long-term follow-up of AS patients have demonstrated predictive value in anticipating the development of IBD. Serologic antibodies characteristic of IBD (ASCA, ANCA) have also been compared; however, results exhibit variability. In this review, we will focus on biomarkers associated with both axial SpA and idiopathic intestinal inflammation, notably enteropathic spondyloarthritis.

Meta-analysis of anti-Saccharomyces cerevisiae antibodies as diagnostic markers of Behçet's disease with gastrointestinal involvement

OBJECTIVE

Due to common exposure to yeast in the alcoholic and baking industry, positive rate of anti-Saccharomyces cerevisiae antibodies (ASCA) is reportedly high in patients with Behçet's disease (BD) who have gastrointestinal symptoms (gastrointestinal BD (GIBD)). We performed a meta-analysis to assess the diagnostic value of ASCA in differentiating patients with BD from those with other chronic inflammatory bowel diseases.

METHODS

The meta-analysis is presented with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-analysis of Observational Studies in Epidemiology checklist. Relevant studies that investigated ASCA levels in patients with BD were retrieved from PubMed, EMBASE, Web of Science, SCOPUS and the Cochrane Library on 12 July 2019; the search was rerun on 12 February 2020. Stata/SE V.12.0 and Meta-DiSc V.1.4 were used to perform the meta-analysis and sensitivity analysis, disaggregated by isotypes of ASCA.

RESULTS

Nine studies were included in the meta-analysis. The results revealed a strong association between ASCA and GIBD, especially ASCA-IgG (OR=5.50 (95% CI 2.58 to 11.55), p=0.000) and ASCA-IgG+IgA (OR=5.36 (95% CI 1.40 to 20.45), p=0.014). The positivity rate of ASCA in GIBD was significantly higher than that in ulcerative colitis (UC): IgA (OR=2.13 (95% CI 1.30 to 3.50), p=0.003); IgG+IgA (OR=2.19 (95% CI 1.03 to 4.66), p=0.042); IgG/IgA ((=2.03 (95% CI 1.30 to 3.17), p=0.002). However, the frequency of ASCA-IgG was significantly higher in patients with Crohn's disease than GIBD (OR=0.48 (95% CI 0.28 to 0.83), p=0.009). There was no significant difference in ASCA positivity between BD without gastrointestinal involvement and healthy controls and between GIBD and intestinal tuberculosis (iTB) (p>0.05).

CONCLUSION

ASCA may play a role in the pathogenesis of gastrointestinal involvement. Negative result of IgG favours the diagnosis of GIBD/BD when differentiated from Crohn's disease. ASCA-IgA showed moderate diagnostic performance in distinguishing GIBD and UC and the diagnostic performance was better in combination with IgG. However, ASCA may not be a useful serologic marker distinguishing GIBD and iTB.

PROSPERO REGISTRATION NUMBER

CRD42020115245.

Biomarkers in Inflammatory Bowel Disease-Associated Spondyloarthritis: State of the Art and Unmet Needs

Inflammatory bowel disease-associated spondyloarthritis is a systemic disease characterized by the chronic inflammation of both the gastrointestinal tract and the musculoskeletal system. Since inflammatory bowel disease-associated spondyloarthritis has been associated with a significant diagnostic delay, which may lead to poor quality of life and progression of joint damage, efforts to discover new reliable and noninvasive diagnostic biomarkers have been made. We reviewed the state of the art of biomarker research in inflammatory bowel disease-associated spondyloarthritis, showing that to date it has been largely unsatisfactory. Only a few of the biomarkers that have been investigated are likely to enter the clinical practice upon further validation in independent cohorts. The research of new and innovative biomarkers for inflammatory bowel disease-associated spondyloarthritis is warranted.

The Pathogenesis of Extraintestinal Manifestations: Implications for IBD Research, Diagnosis, and Therapy

This article reports on the sixth scientific workshop of the European Crohn's and Colitis Organisation [ECCO] on the pathogenesis of extraintestinal manifestations [EIMs] in inflammatory bowel disease [IBD]. This paper has been drafted by 15 ECCO members and 6 external experts [in rheumatology, dermatology, ophthalmology, and immunology] from 10 European countries and the USA. Within the workshop, contributors formed subgroups to address specific areas. Following a comprehensive literature search, the supporting text was finalized under the leadership of the heads of the working groups before being integrated by the group consensus leaders.

Autoantibodies in Spondyloarthritis, Focusing on Anti-CD74 Antibodies

Spondyloarthritis (SpA) is an inflammatory rheumatic disease with diverse clinical presentation. The diagnosis of SpA remains a big challenge in daily clinical practice because of the limitation in specific biomarkers of SpA, more biomarkers are still needed for SpA diagnosis and disease activity monitoring. In the past, SpA was considered predominantly as auto-inflammatory disease vs. autoimmune disease. However, in recent years several researches demonstrated a broad autoantibody response in SpA patients. Study also indicated that mice lack of ZAP70 in T cell develop SpA featured inflammation. These studies indicated the autoimmune features of SpA and gave rise to the potential use of autoantibody in SpA management. In this article, we reviewed recent reports of autoantibodies associated with SpA patients, revealing the autoimmune features of SpA, suggesting the hypothesis that SpA was also an autoimmune disease, studies about the autoimmune features might provide more insights in the pathogenesis of SpA. In addition, as there are two opposite conclusions in the role of anti-CD74 autoantibody in the diagnosis of SpA, we also gave our own data on the diagnostic value of anti-CD74 in Chinese SpA patients. Though our data indicated that anti-CD74 might not be a good biomarker for SpA diagnosis in Asian people, CD74 was still a good molecule target in the research of SpA pathogenesis.

Spondyloarthritis, Acute Anterior Uveitis, and Fungi: Updating the Catterall-King Hypothesis

Spondyloarthritis is a common type of arthritis which affects mostly adults. It consists of idiopathic chronic inflammation of the spine, joints, eyes, skin, gut, and prostate. Inflammation is often asymptomatic, especially in the gut and prostate. The HLA-B*27 allele group, which presents intracellular peptides to CD8+ T cells, is by far the strongest risk factor for spondyloarthritis. The precise mechanisms and antigens remain unknown. In 1959, Catterall and King advanced a novel hypothesis explaining the etiology of spondyloarthritis: an as-yet-unrecognized sexually acquired microbe would be causing all spondyloarthritis types, including acute anterior uveitis. Recent studies suggest an unrecognized sexually acquired fungal infection may be involved in prostate cancer and perhaps multiple sclerosis. This warrants reanalyzing the Catterall-King hypothesis based on the current literature. In the last decade, many links between spondyloarthritis and fungal infections have been found. Antibodies against the fungal cell wall component mannan are elevated in spondyloarthritis. Functional polymorphisms in genes regulating the innate immune response against fungi have been associated with spondyloarthritis (CARD9 and IL23R). Psoriasis and inflammatory bowel disease, two common comorbidities of spondyloarthritis, are both strongly associated with fungi. Evidence reviewed here lends credence to the Catterall-King hypothesis and implicates a common fungal etiology in prostate cancer, benign prostatic hyperplasia, multiple sclerosis, psoriasis, inflammatory bowel disease, and spondyloarthritis. However, the evidence available at this time is insufficient to definitely confirm this hypothesis. Future studies investigating the microbiome in relation to these conditions should screen specimens for fungi in addition to bacteria. Future clinical studies of spondyloarthritis should consider antifungals which are effective in psoriasis and multiple sclerosis, such as dimethyl fumarate and nystatin.

Detection of Crohn Disease in Patients with Spondyloarthropathy: The SpACE Capsule Study

OBJECTIVE

Inflammatory bowel disease (IBD) is generally reported to be associated with spondylarthropathies (SpA) in 5%-15% of cases. Systematic colonoscopic assessment by protocol demonstrated mucosal inflammation characteristic of Crohn disease (CD) in up to one-third of patients with SpA. Video capsule endoscopy (CE) is a superior diagnostic tool to detect small bowel mucosal disease. Our study compared the accuracy of CE to standard colonoscopy for detection of inflammatory bowel lesions in patients with SpA, and to describe predictors of small bowel inflammation (SBI) in this cohort.

METHODS

Prospective cross-sectional study of adult patients followed for SpA. Patients were evaluated by CE and standard colonoscopy with biopsies. SBI was quantified using the Lewis Score. Additional screening tests included fecal calprotectin (FCP), C-reactive protein (CRP), and a diagnostic panel of serologic, inflammatory and genetic tests (SGI).

RESULTS

There were 64 patients recruited (53% female, mean age 42 ± 13 yrs). Chronic gastrointestinal (GI) symptoms were present in 57%. CE revealed significant SBI in 27/64 (42.2%), compared to 7/64 (10.9%) by standard colonoscopy (p = 0.035). Elevated FCP was associated with small bowel CD (OR 4.5, 95% CI 1.01-19.9; p = 0.042). No correlation was observed with presence of GI symptoms, CRP, or SGI results. Finding CD led to a change in management in 65.2% of cases.

CONCLUSION

CE uncovered SBI consistent with CD in 42.2% of patients with SpA, with a significant incremental yield over colonoscopy of 31%. FCP levels were significantly correlated with CE results, while GI symptoms and SGI results were poor predictors of SBI.

Gastrointestinal Symptoms and Elevated Levels of Anti-Saccharomyces cerevisiae Antibodies Are Associated with Higher Disease Activity in Colombian Patients with Spondyloarthritis

Background

Spondyloarthritis (SpA) is a group of articular inflammatory rheumatic diseases that their gastrointestinal manifestations are around 10% of their extra-articular symptoms, supporting that the inflammatory response of the intestinal mucosa could be associated with the clinical status.

Objectives

To investigate the association between gastrointestinal symptoms and autoantibodies and disease activity between SpA patients, healthy subjects (HS), and patients with inflammatory bowel disease (IBD).

Methods

102 SpA patients, 29 IBD patients, and 117 HS were included. Autoantibodies as ASCA, ANCA, anti-tTG, anti-DGP, ANA, and IgA were measured. The patients were assessed to evaluate clinical and gastrointestinal symptoms. An association analysis was performed using Chi square test and a logistic regression.

Results

Significant differences were found for ASCA levels in SpA (28.2%) compared to IBD (14.2%) and HS (6.0%) (p = 0.029), as well as for ANAS in SpA (49.5%) and IBD (37.9%) (p < 0.001) and abdominal pain (p = 0.012) between SpA (54.3%) and IBD (27.5%). Significant associations were found between BASDAI > 4 and gastrointestinal symptoms (p < 0.05) and IgA (p = 0.007). The association for abdominal bloating was maintained (OR: 3.93, CI-95%, 1.14–13.56; p = 0.030).

Conclusions

Gastrointestinal symptoms, ASCA, ANAS, and IgA levels were associated with high disease activity in SpA compared with IBD and HS.

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.

Anti-Saccharomyces cerevisiae antibodies (ASCA) in spondyloarthritis: Prevalence and associated phenotype

OBJECTIVE

The aim of the study was to compare the prevalence of ASCA in spondyloarthrites (SpA) patients and to investigate the association between ASCA status and disease phenotype.

METHODS

We performed a case-control study including SpA individuals fulfilling the ESSG SpA criteria. The following data were collected for analysis: gender, age, disease duration, clinical or associated features of SpA, treatments, HLAB27 and ASCA status. A control group of patients without SpA was also analyzed.

RESULTS

A total of 235 patients with SpA and 54 control patients were studied. The median age of SpA patients (53.6% of male patients, 52.2% of HLAB27) was 46.0 [IQR 35.0-57.0] years old. Disease duration was 60.0 [IQR 24.0-156.0] months. Inflammatory bowel diseases were observed in 11% of SpA patients. ASCA positivity was significantly higher in SpA patients than in control patients (25.5% [95% CI 20.1-31.6] (IgG: 9.8%; IgA: 21.7%) vs. 7.4% [95% CI 2.1-17.9], P=0.004). Multivariate analysis revealed that ASCA positivity was associated with peripheral involvement (OR: 3.30 [1.26-8.62], P=0.015), presence of IBD (OR: 3.43 [1.15-10.20], P=0.026), past of present history of uveitis (OR: 4.36 [1.08-17.64], P=0.039) and arthritis (OR: 3.78 [1.57-9.15], P=0.003).

CONCLUSION

Our results provided evidence that SpA patients had an increased prevalence of ASCA and that ASCA positivity might be associated with a particular phenotype, notably peripheral involvement and uveitis.

Gut inflammation and microbiome in spondyloarthritis

Spondyloarthritis (SpA) is chronic inflammatory disease involving joints and the spine. Bowel inflammation is common in SpA, which may be classified as acute or chronic. Chronic gut inflammation is most common in SpA patients with axial involvement as compared to those presenting with peripheral involvement alone. The pathogenesis of gut inflammation in SpA could be explained by two factors-over-activation of immunological cells and altered gut microbiome. This is exemplified by SpA animal models, namely HLA-B27-expressing transgenic animals and SKG mice models. Immunological mechanisms include homing of activated T cells from gut into synovium, excess pro-inflammatory cytokines secretion by immune cells such as IL-23 and genetic variations in immunological genes. The evidence for role of gut microbiome in SpA is gradually emerging. Recently, metagenomic study of gut microbiome by sequencing of microbial nucleic acids has enabled identification of new microbial taxa and their functions in gut of patients with SpA. In SpA, the gut microbiome could emerge as diagnostic and prognostic marker of disease. Modulation of gut microbiome is slated to have therapeutic potential as well.

The intestinal microbiome in human disease and how it relates to arthritis and spondyloarthritis

Humans and microbes have developed a symbiotic relationship over time, and alterations in this symbiotic relationship have been linked to several immune mediated diseases such as inflammatory bowel disease, type 1 diabetes and spondyloarthropathies. Improvements in sequencing technologies, coupled with a renaissance in 16S rRNA gene based community profiling, have enabled the characterization of microbiomes throughout the body including the gut. Improved characterization and understanding of the human gut microbiome means the gut flora is progressively being explored as a target for novel therapies including probiotics and faecal microbiota transplants. These innovative therapies are increasingly used for patients with debilitating conditions where conventional treatments have failed. This review discusses the current understanding of the interplay between host genetics and the gut microbiome in the pathogenesis of spondyloarthropathies, and how this may relate to potential therapies for these conditions.

Microbiology, genomics, and clinical significance of the Pseudomonas fluorescens species complex, an unappreciated colonizer of humans

Pseudomonas fluorescens is not generally considered a bacterial pathogen in humans; however, multiple culture-based and culture-independent studies have identified it at low levels in the indigenous microbiota of various body sites. With recent advances in comparative genomics, many isolates originally identified as the "species" P. fluorescens are now being reclassified as novel Pseudomonas species within the P. fluorescens "species complex." Although most widely studied for its role in the soil and the rhizosphere, P. fluorescens possesses a number of functional traits that provide it with the capability to grow and thrive in mammalian hosts. While significantly less virulent than P. aeruginosa, P. fluorescens can cause bacteremia in humans, with most reported cases being attributable either to transfusion of contaminated blood products or to use of contaminated equipment associated with intravenous infusions. Although not suspected of being an etiologic agent of pulmonary disease, there are a number of reports identifying it in respiratory samples. There is also an intriguing association between P. fluorescens and human disease, in that approximately 50% of Crohn's disease patients develop serum antibodies to P. fluorescens. Altogether, these reports are beginning to highlight a far more common, intriguing, and potentially complex association between humans and P. fluorescens during health and disease.

Gut microbes, immunity, and spondyloarthritis

The last decade has witnessed an explosion of studies evaluating the impact of the human microbiota on a variety of disease states. The microbiota can impact diseases in multiple ways, including through abnormalities in the diversity and contents of the microbiota, as well as by acting as targets of immunologic dysregulation. Herein, evidence that the microbiota in spondyloarthritis is both altered and abnormally targeted by the immune system will be presented.

Spondyloarthritis and inflammatory bowel disease. Comorbidity and treatment implications

Spondyloarthritides (SpA) and inflammatory bowel disease (IBD) are chronic, idiopathic inflammatory disorders of the axial and peripheral joints and the intestinal tract, respectively, affecting up to 1 % of the population. There is clinical and genetic evidence supporting some degree of overlap between the pathogenesis of these two entities. Nevertheless, their treatment is at times conflicting. NSAIDs, although useful in SpA, are considered to be possible risk factors for flares in IBD. Moreover, etanercept, a soluble TNF receptor blocker used in SpA, is ineffective in IBD. As patients with SpA often develop microscopic gut inflammation, it is important to understand the impact on disease progression or even therapeutic response. Further research is mandatory in this regard.

Deoxyribonuclease activity of polyclonal IgGs: a putative serological marker in patients with spondyloarthritides

Antibodies executing catalytic activity are referred to as antibody enzymes or short "abzymes" and may have diagnostic relevance. Abzymes with deoxyribonuclease (DNase) activity have been demonstrated in patients with autoimmune and infectious diseases. Despite several reports on the occurrence of DNase abzymes in systemic autoimmune rheumatic diseases, conclusive data about DNase activity of antibodies in patients with spondyloarthritides (SpAs) are lacking. In recent cross-sectional studies evaluating levels of IgG DNase activity in patients with psoriatic arthritis (PsA), reactive arthritis (ReA), and ankylosing spondylitis (AS), DNase activity of IgG has been assessed by the rivanol clot method and confirmed by agarose gel electrophoresis. Remarkably, levels of IgG DNase activity were significantly higher in sera of SpA patients than those in control subjects. In patients with PsA, ReA, and AS, a positive correlation of DNase IgG activity with synovitis, disease activity, and stage of spondylitis was observed, respectively. Given the involvement of autoimmune reactions in cytolysis and connective tissue degradation in PsA, ReA, and to a lesser extent in AS, abzymes might have an impact on the pathophysiology of SpAs. Detection of IgG DNase activity in patients suffering from SpA represents an exciting new research field and may assist in the differential diagnosis of SpA.

Pfit is a structurally novel Crohn's disease-associated superantigen

T cell responses to enteric bacteria are important in inflammatory bowel disease. I2, encoded by the pfiT gene of Pseudomonas fluorescens, is a T-cell superantigen associated with human Crohn's disease. Here we report the crystal structure of pfiT at 1.7Å resolution and provide a functional analysis of the interaction of pfiT and its homolog, PA2885, with human class II MHC. Both pfiT and PA2885 bound to mammalian cells and stimulated the proliferation of human lymphocytes. This binding was greatly inhibited by anti-class II MHC HLA-DR antibodies, and to a lesser extent, by anti HLA-DQ and DP antibodies, indicating that the binding was class II MHC-specific. GST-pfiT efficiently precipitated both endogenous and in vitro purified recombinant HLA-DR1 molecules, indicating that pfiT directly interacted with HLA-DR1. Competition studies revealed that pfiT and the superantigen Mycoplasma arthritidis mitogen (MAM) competed for binding to HLA-DR, indicating that their binding sites overlap. Structural analyses established that pfiT belongs to the TetR-family of DNA-binding transcription regulators. The distinct structure of pfiT indicates that it represents a new family of T cell superantigens.

Human inflammatory bowel disease (IBD) is a family of chronic inflammatory disorders of the gastrointestinal tract which affect genetically susceptible individuals. IBD is a lifelong disease involving mostly young people, often severely. Crohn's disease (CD) and ulcerative colitis are the two major forms of IBD. Although the exact cause of these diseases remains unknown, both genetic and environmental factors together play significant roles in the disease pathogenesis. Several lines of evidence implicate commensal bacteria as an important pathogenic element in clinical disease, particularly in CD. We recently identified a novel microbial gene, I2, encoded by Pseudomonas fluorescens, a gram-negative commensal, which may be involved in the pathogenesis of CD. Both molecular and immunological approaches were used to identify the human receptor for the microbial antigen encoded by I2, to characterize the ligand-receptor interactions, and to determine the three-dimensional structure of the microbial gene product. In particular, we show that the pfiT is a T cell superantigen, which may help to explain how microbial flora can trigger immune activation in IBD, and may provide the groundwork for novel therapies to treat CD.

Elevated serum anti-flagellin antibodies implicate subclinical bowel inflammation in ankylosing spondylitis: an observational study

INTRODUCTION

Ankylosing spondylitis (AS) and inflammatory bowel disease (IBD) share genetic and clinical features. IBD is associated with the presence of antibodies to a variety of commensal microorganisms including anti-Saccharomyces cerevesiae antibodies (ASCA), antineutrophil cytoplasmic antibodies (ANCA), anti-I2 (associated with anti-Pseudomonas activity), anti-Eschericia coli outer membrane porin C (anti-OmpC) and anti-flagellin antibodies (anti-CBir1). Subclinical intestinal inflammation may be present in up to 65% of patients with AS. This study evaluated the presence of antimicrobial antibodies in patients with AS alone, patients with AS and concomitant IBD (AS-IBD) and a control group of patients with mechanical back pain (MBP).

METHODS

Sera were tested by ELISA for ASCA IgG and IgA, anti-OmpC, anti-CBir1 and ANCA in 76 patients with AS alone, 77 patients with AS-IBD and 48 patients with MBP. Antibody positivity rates, median quantitative antibody levels and the proportion of patients with antibody levels in the 4th quartile of a normal distribution were compared between the three groups of patients.

RESULTS

Patients with AS alone demonstrated higher anti-CBir1 antibody positivity rates and median antibody levels than MBP patients. Anti-CBir1 positivity in AS was associated with elevation of acute phase reactants. AS-IBD patients demonstrated elevated responses when compared to AS alone for ASCA, anti-OmpC and anti-CBir1. Quartile analysis confirmed the findings.

CONCLUSIONS

These data suggest that adaptive immune responses to microbial antigens occur in AS patients without clinical IBD and support the theory of mucosal dysregulation as a mechanism underlying the pathophysiology of AS.

Markers of intestinal inflammation in patients with ankylosing spondylitis: a pilot study

Introduction

Inflammatory bowel disease (IBD) and ankylosing spondylitis (AS) are similar chronic inflammatory diseases whose definitive etiology is unknown. Following recent clinical and genetic evidence supporting an intertwined pathogenic relationship, we conducted a pilot study to measure fecal calprotectin (fCAL) and IBD-related serologies in AS patients.

Methods

Consecutive AS patients were recruited from a long-term prospectively collected longitudinal AS cohort at Cedars-Sinai Medical Center. Controls were recruited from Cedars-Sinai Medical Center employees or spouses of patients with AS. Sera were tested by ELISA for IBD-associated serologies (antineutrophil cytoplasmic antibodies (ANCA), anti-Saccharomyces cerevisiae antibody IgG and IgA, anti-I2, anti-OmpC, and anti-CBir1). The Bath Ankylosing Spondylitis Disease Activity Index, the Bath Ankylosing Spondylitis Functional Index, and the Bath Ankylosing Spondylitis Radiology Index were completed for AS patients.

Results

A total of 81 subjects (39 AS patients and 42 controls) were included for analysis. The average age of AS patients was 47 years and the average disease duration was 22 years. AS patients were predominantly male; 76% were HLA-B27-positive. Median fCAL levels were 42 μg/g and 17 μg/g in the AS group and controls, respectively (P < 0.001). When using the manufacturer's recommended cutoff value for positivity of 50 μg/g, stool samples of 41% of AS patients and 10% of controls were positive for fCAL (P = 0.0016). With the exception of ANCA, there were no significant differences in antibody levels between patients and controls. Median ANCA was 6.9 ELISA units in AS patients and 4.3 ELISA units in the controls. Among AS patients stratified by fCAL level, there were statistically significant differences between patients and controls for multiple IBD-associated antibodies.

Conclusion

Calprotectin levels were elevated in 41% of patients with AS with a cutoff value for positivity of 50 μg/g. fCAL-positive AS patients displayed higher medians of most IBD-specific antibodies when compared with healthy controls or fCAL-negative AS patients. Further studies are needed to determine whether fCAL can be used to identify and characterize a subgroup of AS patients whose disease might be driven by subclinical bowel inflammation.

The transition of acute to chronic bowel inflammation in spondyloarthritis

That gut and joint inflammation are linked in spondyloarthritis (SpA) has been recognized for almost three decades. Intriguingly, microscopic gut inflammation, which occurs frequently in patients with SpA, is an important risk factor for clinically overt Crohn's disease and ankylosing spondylitis. This Review describes current insights into the underlying mechanisms that lead to chronic gut inflammation in patients with SpA. We propose that the development of chronic bowel inflammation in these individuals occurs through a transition phase, in which inflammation evolves from an acute into a chronic state. Our transition model implies that different cell types are involved at different stages during disease progression, with stromal cells having an important role in chronicity. In addition, deficient regulatory feedback mechanisms or genetically determined alterations in antigen presentation, endoplasmic reticulum stress, autophagy or cytokine signaling might also favor a transition from self-limiting acute inflammation to chronic inflammation. We anticipate that this transition phase might be an important window for therapeutic intervention.

Serologic markers: impact on early diagnosis and disease stratification in inflammatory bowel disease

Inflammatory bowel disease (IBD) is difficult to diagnose, and differentiating between ulcerative colitis (UC) and Crohn's disease (CD) can be challenging. Overlapping symptoms of UC and CD often delay diagnosis, despite availability of endoscopic, radiologic, and histologic tools. This delay in diagnosis is quite common in clinical practice, which may also delay initiation of appropriate treatment. Abnormal immune responses found in IBD have led to the use of serum biomarkers (eg, anti-Saccharomyces cerevisiae antibody [ASCA], perinuclear antineutrophil cytoplasmic antibody [pANCA], antibodies to flagellin [anti-CBir1]) to improve diagnostic confidence in IBD. These biomarkers are beginning to be used to stratify patients with UC and CD according to disease phenotype and risk of complications. Associations between quantity and quality of immune reactivity and severe disease phenotypes are increasingly evident. This suggests that serologic panels of multiple IBD biomarkers can be used to identify the relative risk of progression to complicated disease behaviors, and that this information may ultimately impact therapeutic decisions. This review discusses the diagnostic process and challenges in IBD, with emphasis on the role that serologic markers may play in addressing these challenges.

pANCA, ASCA, and OmpC antibodies in patients with ankylosing spondylitis without inflammatory bowel disease

OBJECTIVE

Patients with ankylosing spondylitis (AS) can suffer concurrently from inflammatory bowel disease (IBD), as ulcerative colitis (UC) or Crohn's disease (CD). Serological markers have been described to diagnose IBD. We investigated IBD serological markers in AS patients without IBD and whether these antibodies enable differentiating patients with AS and IBD from those without IBD.

METHODS

Frequencies of perinuclear antineutrophil cytoplasmic antibodies (pANCA), antibodies to the cell-wall mannan of Saccharomyces cerevisiae (ASCA), and antibodies to porin protein C of Escherichia coli (OmpC) were evaluated in 179 patients: 52 with AS, 50 with UC, 51 with CD, and 26 with IBD and AS. Patient groups were matched for age and sex. All AS patients fulfilled the 1984 modified New York criteria. IBD was ascertained by clinical, endoscopic, and microscopic findings.

RESULTS

In 55% of the AS patients without manifest IBD at least one antibody associated with IBD was observed. pANCA, ASCA (IgA and/or IgG), and OmpC antibodies were found in 21%, 30%, and 19% of the AS patients, respectively. pANCA was more frequently present in AS with concurrent UC than in AS alone (OR 8.2, 95% CI 1.2-55.6), thus being an indicator for UC in AS patients.

CONCLUSION

Antibodies associated with IBD are detectable in more than half of AS patients without symptoms or signs of IBD. A relatively recent marker in this setting, OmpC antibodies, does not contribute to the differentiation between AS and type of IBD. Presence of pANCA, however, is significantly increased in AS patients who also have UC, and is an indicator to perform endoscopy. These results corroborate a pathophysiological link between AS and IBD.