Radiological sacroiliitis, a hallmark of spondylitis, is linked with CARD15 gene polymorphisms in patients with Crohn's disease

NOD2 and Crohn's Disease Clinical Practice: From Epidemiology to Diagnosis and Therapy, Rewired

Crohn's disease (CD) is a chronic inflammatory bowel disease with a multifactorial pathogenesis involving environmental and genetic factors. Since the late 20th century, the discovery of the first susceptibility gene (NOD2, previously referred to as CARD15) for CD has paved the way for further investigations into the correlations between clinical features and genetics, and its potential impact on clinical practice has fueled the research in the last 2 decades. Recent therapeutic advancements involving novel biologic drugs and small molecules have shifted inflammatory bowel disease management from a disease-centered to a patient-centric approach. To date, the role of NOD2 has not been fully understood yet. Recent data suggest that its clinical impact may be greater than currently recognized. This review overviews the most common NOD2 variants' role in real-life clinical practice. These genetic variants increase the risk of developing the disease and can aid in tailoring diagnosis and treatment. They are associated with the stricturing phenotype and ileal involvement and increase the risk of steroid refractoriness. In the meantime, limited and inconclusive evidence exists regarding their predictive role in response to azathioprine, biologic drugs, and small molecules. Eventually, their role in increasing the risk for surgery is evident, especially in those with the L1007fs variant. If further trials will support the initial evidence reported so far, NOD2 genetic variants will emerge as possible candidates for developing precision medicine in CD.

Extraintestinal Manifestations of Inflammatory Bowel Disease: Current Concepts, Treatment, and Implications for Disease Management

Inflammatory bowel diseases (IBDs) are systemic diseases that manifest not only in the gut and gastrointestinal tract, but also in the extraintestinal organs in many patients. The quality of life for patients with IBD can be substantially affected by these extraintestinal manifestations (EIMs). It is important to have knowledge of the prevalence, pathophysiology, and clinical presentation of EIMs in order to adapt therapeutic options to cover all aspects of IBD. EIMs can occur in up to 24% of patients with IBD before the onset of intestinal symptoms, and need to be recognized to initiate appropriate diagnostic procedures. EIMs most frequently affect joints, skin, or eyes, but can also affect other organs, such as the liver, lung, and pancreas. It is a frequent misconception that a successful therapy of the intestinal inflammation will be sufficient to treat EIMs satisfactorily in most patients with IBD. In general, peripheral arthritis, oral aphthous ulcers, episcleritis, or erythema nodosum can be associated with active intestinal inflammation and can improve on standard treatment of the intestinal inflammation. However, anterior uveitis, ankylosing spondylitis, and primary sclerosing cholangitis usually occur independent of disease flares. This review provides a comprehensive overview of epidemiology, pathophysiology, clinical presentation, and treatment of EIMs in IBD.

Managing Psoriatic Arthritis With Inflammatory Bowel Disease and/or Uveitis

Psoriatic arthritis (PsA) is a chronic inflammatory disease that presents with psoriasis (PsO), peripheral and axial arthropathy. The heterogeneity of disease presentation leads to the term "psoriatic disease (PsD)" which is thought to better encompass the range of clinical manifestations. PsA is associated with several comorbidities such as cardiovascular diseases, metabolic syndrome and other extra-articular manifestations including uveitis, and inflammatory bowel disease (IBD). While novel therapeutics are being developed following advances in our understanding of the pathogenesis of the disease, the diverse combinations of PsA with its various comorbidities still pose a clinical challenge in managing patients with PsA. This article reviews our current understanding of the pathogenesis of PsA and how various pathways in the pathogenesis lead to the two comorbid extra-articular manifestations - uveitis and IBD. We also review current evidence of treatment strategies in managing patients with PsA with comorbidities of uveitis and/or IBD.

[Update: enterogenic spondylarthritis]

Spondylarthritis (SpA) is one of the most frequent extraintestinal manifestations of chronic inflammatory bowel disease (IBD). Several arthritogenic enterobacterial infections can induce sequelae such as reactive SpA. Studies on the gut-synovium axis in view of genetic, immunological, clinical and therapeutic aspects has made enterogenic SpA a model disease of all forms of SpA. The same applies for investigating IBD, as subclinical gut inflammation seen in SpA patients has provided significant evidence for a better understanding of mucosa-associated early immune events in Crohn's disease (CD). This article summarizes the pathognomonic clinical features, diagnostic steps, differential diagnosis and current pathogenetic models of enterogenic SpA. Knowledge of pathogenetic contexts leads to concrete treatment recommendations. These vary individually depending on the underlying IBD, on the inflammatory intestinal or rheumatic activity and on the rheumatological manifestation pattern.

Prevalence of axial spondyloarthritis in patients with inflammatory bowel disease using cross-sectional imaging: a systematic literature review

BACKGROUND

Patients with inflammatory bowel disease (IBD) have an excess burden of axial spondyloarthritis (axSpA), which, if left untreated, may significantly impact on clinical outcomes. We aimed to estimate the prevalence of axSpA, including previously undiagnosed cases, in IBD patients from studies involving cross-sectional imaging and identify the IBD features potentially associated with axSpA.

METHODS

PubMed, Embase and Cochrane databases were searched systematically between 1990 and 2018. Article reference lists and key conference abstract lists from 2012 to 2018 were also reviewed. All abstracts were reviewed by two authors to determine eligibility for inclusion. The study inclusion criteria were (a) adults aged 18 years or above, (b) a clinical diagnosis of IBD and (c) reporting identification of sacroiliitis using cross-sectional imaging.

RESULTS

A total of 20 observational studies were identified: 12 used CT, 6 used MR and 2 utilised both computed tomography (CT) and magnetic resonance (MR) imaging. Sample sizes ranged from 25 to 1247 (a total of 4096 patients); 31 studies were considered to have low selection bias, 13 included two or more radiology readers, and 3 included rheumatological assessments. The prevalence of sacroiliitis, the most commonly reported axSpA feature, ranged from 2.2% to 68.0% with a pooled prevalence of 21.0% [95% confidence interval (CI) 17-26%]. Associated IBD features include increasing IBD duration, increasing age, male sex, IBD location, inflammatory back pain and peripheral arthritis. No significant difference in the prevalence of sacroiliitis between Crohn's disease and ulcerative colitis was identified. Study limitations include variability in the individual study sample sizes and patient demographics.

CONCLUSION

This review highlights the need for larger, well-designed studies using more sensitive imaging modalities and multivariable modelling to better estimate the prevalence of axSpA in IBD. An improved knowledge of the IBD phenotype(s) associated with axSpA and use of cross-sectional imaging intended for IBD assessment to screen for axSpA may help clinicians identify those patients most at risk.

Inflammatory Bowel Diseases and Coexisting Spondyloarthritis: A Neglected and too Often Under-Reported Association by Radiologists. A Multicenter Study by Italian Research Group of Imaging in Rheumatology

Purpose: The purpose of this study was to evaluate the prevalence and the underreporting rate of sacroiliitis (SI) in a large cohort of patients with biopsy-proved Crohn’s disease (CD) who underwent magnetic resonance enterography (MRE) or computed tomography enterography (CTE). Materials and Methods: Patients with CD were recruited from eight Italian health centers in the period from January 2013 to December 2017. Disease activity was recorded according to the CD activity index (CDAI). The scans were read by two blinded readers who defined the presence of SI according to Assessment of SpondyloArthritis International Society (ASAS) classifications and European League Against Rheumatism (EULAR) recommendations. Moreover, SI was scored using a simplified Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system. Results: Interobserver agreement in diagnosing SI on imaging was good (K = 0.72–0.83). SI was diagnosed in 129 (14.4%, 54 men, 75 women) out of 894 patients; however, sacroiliac joint (SIJ) abnormalities were not mentioned in the radiological reports of 112 patients (86%). Fifty (38.7%) out of 129 patients also underwent a subsequent SIJ evaluation through a dedicated MRI protocol to confirm SI. SI was found in a higher percentage of patients with “active” than “inactive” CD (18% vs. 4%). Conclusion: This study confirms the feasibility of CTE and MRE for the screening of SI in CD patients; however, it also underlines the remarkable problem concerning the underreporting of this entity in radiological practice.

Bidirectional Causal Associations Between Inflammatory Bowel Disease and Ankylosing Spondylitis: A Two-Sample Mendelian Randomization Analysis

Background

Associations between inflammatory bowel disease (IBD) [including ulcerative colitis (UC) and Crohn’s disease (CD)] and ankylosing spondylitis (AS) were discovered in observational studies, but no evidence supported the causal relationship between the two diseases.

Methods

We employed two-sample Mendelian randomization (MR) to estimate the unconfounded bidirectional causal associations between IBD (including UC and CD) and AS. We selected single-nucleotide polymorphisms (SNPs) from genome-wide association studies (GWAS) after strictly assessing the quality of the studies in the IEU GWAS database. Sensitivity analyses were also conducted to verify whether heterogeneity and pleiotropy can bias the MR results.

Results

We found positive causal effects of genetically increased UC, CD, and IBD risk on AS (e.g., UC and AS, IVW OR: 1.0256, 95% CI: 1.0130∼1.0385, p = 6.43E-05). However, we did not find significant causal associations of AS with UC, CD, or IBD (e.g., AS and UC, IVW OR: 1.1858, 95% CI: 0.8639∼1.6278, p = 0.2916). The sensitivity analysis also confirmed that horizontal pleiotropy was unlikely to bias the causality (e.g., UC and AS, MR-Egger: intercept p = 0.1326). The leave-one-out analysis also demonstrated that the observed links were not driven by SNP. No evidence of heterogeneity was found between the genetic variants (e.g., UC and AS, MR-Egger: Q statistic = 43.1297, I²<0.0001, p = 0.7434).

Conclusion

Our results provide new evidence indicating there are positive causal effects of IBD on AS in the European population. We suggest that the features of inflammatory bowel disease in particular should be assessed in the diagnosis of ankylosing spondylitis. We also provide some advice for preventing and treating the two diseases.

Gut Microbiome and Its Interaction with Immune System in Spondyloarthritis

Emerging evidence suggests there is a gut-joint axis in spondyloarthritis (SpA). In a study, subclinical gut inflammation occurred in nearly 50% of SpA. Chronic gut inflammation also correlated with disease activity in SpA. Trillions of microorganisms reside in the human gut and interact with the human immune system. Dysbiosis affects gut immune homeostasis and triggers different autoimmune diseases including SpA. The absence of arthritis in HLA-B27 germ-free mice and the development of arthritis after the introduction of commensal bacteria to HLA-B27 germ-free mice proved to be the important role of gut bacteria in shaping SpA, other than the genetic factor. The recent advance in gene sequencing technology promotes the identification of microorganisms. In this review, we highlighted current evidence supporting the link between gut and axial SpA (axSpA). We also summarized available findings of gut microbiota and its interaction with the immune system in axSpA. Future research may explore the way to modulate gut microorganisms in axSpA and bring gut microbiome discoveries towards application.

Etiopathogenesis of sacroiliitis: implications for assessment and management

The sacroiliac joints connect the base of the sacrum to the ilium. When inflamed, they are suspected to cause low back pain. Inflammation of the sacroiliac joints is called sacroiliitis. The severity of the pain varies and depends on the degree of inflammation. Sacroiliitis is a hallmark of seronegative spondyloarthropathies. The presence or absence of chronic sacroiliitis is an important clue in the diagnosis of low back pain. This article aims to provide a concise overview of the anatomy, physiology, and molecular biology of sacroiliitis to aid clinicians in the assessment and management of sacroiliitis. For this narrative review, we evaluated articles in English published before August 2019 in PubMed. Then, we selected articles related to the painful manifestations of the sacroiliac joint. From the retrieved articles, we found that chronic sacroiliitis may be caused by various forms of spondyloarthritis, such as ankylosing spondyloarthritis. Sacroiliitis can also be associated with inflammatory bowel disease, Crohn’s disease, gout, tuberculosis, brucellosis, and osteoarthritis, indicating common underlying etiological factors. The pathophysiology of sacroiliitis is complex and may involve internal, environmental, immunological, and genetic factors. Finally, genetic factors may also play a central role in progression of the disease. Knowing the genetic pre-disposition for sacroiliitis can be useful for diagnosis and for formulating treatment regimens, and may lead to a substantial reduction in disease severity and duration and to improved patient performance.

Rheumatic manifestations in inflammatory bowel disease

Rheumatic manifestations are the most frequent extra-intestinal manifestations (EIMs) in inflammatory bowel disease (IBD) patients, and they are responsible for a relevant reduction of quality of life. IBD is associated with a variety of musculoskeletal manifestations such as arthritis and non-inflammatory pain as well as with metabolic diseases, such as osteoporosis. Different imaging techniques (primarily ultrasound, magnetic resonance imaging and X-rays) can help the clinician to correctly identify the nature of manifestations and to treat the patient accordingly. Nowadays, in the setting of IBD-related arthritides, different drugs are available and can be effective on both articular and intestinal involvement. Therefore, a multi-disciplinary approach provides an early diagnosis and a better clinical outcome that can only be given from the recognition and consideration of the different EIMs. As for rheumatic manifestations, namely IBD-related arthritis, an early intervention allows to control disease activity and to prevent structural damage.

Pathogenesis and clinical perspectives of extraintestinal manifestations in inflammatory bowel diseases

A considerable number of patients with inflammatory bowel disease (IBD) experience extraintestinal manifestations (EIMs), which can present either before or after IBD diagnosis. Unraveling the pathogenic pathways of EIMs in IBD is challenging because of the lack of reliable criteria for diagnosis and difficulty in distinguishing EIMs from external pathologies caused by drugs or other etiologies. Optimizing treatment can also be difficult. Early diagnosis and management of EIM revolve around multidisciplinary teams, and they should have the resources necessary to make and implement appropriate decisions. In addition, specialists of the affected organs should be trained in IBD treatment. Furthermore, patient awareness regarding the extraintestinal symptoms of IBD is of paramount importance for improving patient understanding of disease and health outcomes. Herein, we review the pathogenesis and clinical perspectives of EIMs in IBD.

Infliximab levels and antibodies in IBD-related peripheral arthralgia

BACKGROUND

Extra-intestinal manifestations (EIM) are common in inflammatory bowel diseases (IBD) and may affect up to 40% of the patients during the course of the disease. Peripheral arthralgia (PA) is by far the most common EIM. To date, TNFα inhibitors are the most established treatment for EIMs in IBD. Infliximab (IFX) trough levels (TL) and anti-IFX antibodies (ATI) are correlated with multiple outcomes in IBD such as clinical response and remission, mucosal healing, fistular healing, and more. So far, a correlation between PA and IFX TL\ATI has not been evaluated.

METHODS

This retrospective study included IBD patients followed by the gastroenterology department of Sheba Medical Center. Patients with active PA at onset of IFX treatment were included. IFX TL and ATI were evaluated at week 6, 14, and 26 and correlated with PA persistence.

RESULTS

Forty patients (37 Crohn's and 3 ulcerative colitis) with IBD-related PA were included. The overall prevalence of PA was 55% (22/40), 42.5% (17/40), and 55% (22/40) after 6, 14, and 26 weeks, respectively. IFX trough drug levels were not associated with reported PA at week 6 [median, 11.8 μg/ml (IQR 6.6-15.5) vs 10.05 μg/ml (IQR 7.35-12.87), p = 0.56], week 14 [median, 4.7 μg/ml (IQR 2.3-7) vs 3.1 μg/ml (IQR 1.35-7.35), p = 0.55], and week 26 [median, 3 μg/ml (IQR 1.15-5.17) vs 3.4 μg/ml (IQR 0.13-6.75), p = 0.94]. Detectable ATI were significantly more prevalent in patients with PA than in patients without PA at week 26 [11/22 (50%) vs 3/18 (16.7%), p = 0.028].

CONCLUSIONS

In patients with IBD-related PA, ATI are associated with an increased risk of persistence of PA. No direct correlation was demonstrated between IFX TL and persistence of PA.

[Systemic manifestations of inflammatory bowel diseases]

The article is devoted to the current data regarding the pathogenesis, classification and frequency of extraintestinal manifestations (EIMs) in inflammatory bowel diseases. We discuss two distinct theories of EIMs pathogenesis. First, EIMs arise from an extension of antigen-specific immune responses from the intestine to non-intestinal sites. Second, EIMs are independent inflammatory events initiated or perpetuated by the presence of IBD or by shared genetic or environmental risk factors in the host. These mechanisms are not mutually exclusive and may contribute to varying degrees in different EIMs. Early diagnosis of EIMs contributes to prevention disability and enhancement of quality of life of IBD patients. It is concluded that treatment of extraintestinal manifestations should be carried out taking into account the course of the IBD and the multidisciplinary approach, which requires close cooperation of doctors of various specialties. Assessment of prognostic markers and predictors for EIM in IBD will be part of a future investigation.

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.

Extraintestinal manifestations in inflammatory bowel disease - epidemiology, genetics, and pathogenesis

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder, primarily of, but not restricted to the gut. Extraintestinal manifestations (EIMs) are frequently observed and involve the joints, eyes, hepatobiliary tract, and skin. Areas covered: In this review, we discuss classical EIM focusing on epidemiology, genetics, and pathogenesis, highlighting recent advances in the understanding of EIM. We further discuss treatment-induced immunological phenomena, which are increasingly recognized and might challenge IBD-treating physicians in the era of biological treatment. Expert opinion: EIM considerably contributes to morbidity and mortality. Genetic studies have revealed a common genetic background between EIM and IBD and among specific EIM. Identified protein interactions have been shown to cluster in shared biological pathways. However - despite these recent advances - pathogenesis of EIM is at best partially understood. Several pathogenic mechanisms have been proposed such as upregulation of tumor necrosis factor, aberrant lymphocyte homing, and cross-reactive antigen presentation. It still remains unclear whether EIM is a direct result of the inflammatory process in the gut or rather a consequence of a shared genetic background leading to dysfunctional immune responses to environmental stimuli. Exploration and understanding of EIM genetics and pathophysiology will pave the road for better and more efficacious treatment options in the future.

Red flags for appropriate referral to the gastroenterologist and the rheumatologist of patients with inflammatory bowel disease and spondyloarthritis

Collaboration between gastroenterologists and rheumatologists is recommended for the correct management of patients with associated spondyloarthritis (SpA) and inflammatory bowel disease (IBD). We aimed to establish the appropriateness of several red flags for a prompt specialist referral. A systematic review of the literature was performed using the GRADE method to describe the prevalence of co-existing IBD-SpA and the diagnostic accuracy of red flags proposed by a steering committee. Then, a consensus among expert gastroenterologists and rheumatologists (10 in the steering committee and 13 in the expert panel) was obtained using the RAND method to confirm the appropriateness of each red flag as 'major' (one sufficient for patient referral) or 'minor' (at least three needed for patient referral) criteria for specialist referral. The review of the literature confirmed the high prevalence of co-existing IBD-SpA. Positive and negative predictive values of red flags were not calculated, given the lack of available data. A consensus among gastroenterology and rheumatology specialists was used to confirm the appropriateness of each red flag. Major criteria to refer patients with SpA to the gastroenterologist included: rectal bleeding, chronic abdominal pain, perianal fistula or abscess, chronic diarrhoea and nocturnal symptoms. Major criteria to refer patients with IBD to the rheumatologist included: chronic low back pain, dactylitis, enthesitis and pain/swelling of peripheral joints. Several major and minor red flags have been identified for the diagnosis of co-existing IBD-SpA. The use of red flags in routine clinical practice may avoid diagnostic delay and reduce clinic overload.

Arthropathies in Inflammatory Bowel Disease: A Review for Clinicians

Inflammatory bowel disease (IBD) is a systemic, chronic autoimmune disease of the digestive tract. The etiology and pathophysiology of IBD is not fully understood, though it is believed to be due to a complex interaction among the patient's genotype, immune system, and environmental factors. Inflammatory bowel disease is frequently accompanied by extraintestinal manifestations that occur in almost half of all patients. The most common extraintestinal manifestation that occurs is joint disease, collectively termed the arthropathies of IBD. While epidemiological studies have estimated that the arthropathies of IBD occur in over 46% of the IBD population, there is a paucity of nursing literature concerning the extraintestinal manifestations of IBD and the role of nurses in patient care. Thus, the purpose of this article is to facilitate a greater understanding for nurses and nurse clinicians regarding the arthropathies associated with IBD including classifications, pathophysiology, diagnosis, and management.

Contribution of ancient human remains analysis to the understanding of the variability in HLA-B gene variants in relation to the diagnosis of spondyloarthropathies

Genetic investigations on ancient human remains affected by rheumatological pathologies are a research field of particular interest for identifying the pathogenesis of diseases, especially those having an autoimmune background such as spondyloarthopaties (SpA). Reliable studies concerning this topic require collaboration between multiple disciplines, usually starting from paleopathologic observations up to molecular genetic screening. Here, we focused our investigation in a medieval necropolis in the Basque Country (13th-15th century, N = 163), which presents a high frequency of joint pathologies through two approaches: on the one hand, the analysis of joint manifestations for the differential diagnosis of the SpA and, on the other hand, the determination of the alleles of the HLA-B gene. The morphological analysis allowed determining that 30% of the individuals had rheumatic bone manifestations, with SpA being the most frequent (45%). The genetic analysis of individuals with and without pathologies, based on the study of the HLA-B gene, allowed finding 17 alleles for this gene, with HLA-B40, HLA-B27 and HLA-B35 being the most frequent. Although these alleles have been traditionally described as genetic markers associated to the development of SpA, in this study they were also found in individuals with other rheumatic diseases (osteoarthritis and rheumatoid arthritis) and even in individuals without pathologies. These data confirm the complexity of the relationship of the HLA-B gene variants with SpA, since it is not possible to establish a diagnosis of SpA with these variants alone. However, we suggest that allele HLA-B40, in combination with some specific rheumatic bone manifestations, facilitates the diagnosis of SpA.

The clinical utility of human leucocyte antigen B27 in axial spondyloarthritis

The association between HLA-B27 and AS was first established in the early 1970s. Since then, our understanding of this disease has changed, such that we now recognize AS to be the extreme of the clinical phenotype within a disease spectrum known as axial SpA (axSpA). Recent advances in therapeutic options have driven the need for earlier diagnosis and many screening strategies have been proposed to facilitate this. In parallel, our understanding of axSpA genetics, and especially the contribution of HLA-B27, has expanded. In this article we will present and discuss the evidence supporting the use of HLA-B27 in clinical practice. We will briefly summarize the evolution of the concept of axSpA, the prevalence of HLA-B27 and axSpA and the potential role of HLA-B27 in the aetiopathogenesis of axSpA and focus on the utility of HLA-B27 in everyday clinical practice.

NOD2/CARD15 gene mutations in patients with gouty arthritis

Nucleotide binding and oligomerization domains/caspase recruitment domain-containing protein 15 (NOD2/CARD15) is a cytoplasmic molecule controlling apoptosis and inflammatory processes by recognizing some microbial components. We aimed to identify the frequencies of NOD2/CARD15 gene mutations in patients with gouty arthritis and to determine their possible correlation with the disease phenotype. The study included 93 patients with gouty arthritis and 51 healthy controls matched for age, gender, and ethnicity. The NOD2/CARD15 R702W and G908R gene mutations were explored by the polymerase chain reaction restriction fragment length polymorphism method while the 3020insC mutation was analyzed by DNA sequencing. The mean patient age was 54.2 ± 14.2 years and mean duration of the disease was 3.1 ± 2.9 years. The first metatarsophalangeal and finger joint involvements were detected in 72 (77.4%) and 18 (19.5%) patients, respectively. Ankle arthritis and knee arthritis were detected in 43 (46.2%) and 20 (21.5%) patients, respectively. In total, 4 (9%) heterozygous mutations were detected in the G908R and R702W genes, while no mutation was detected in the 3020insC gene. Compared to the control group, there were no significant differences in all three DNA regions (G908R, R702W, and 3020insC; p = 0.452, p = 0.583, and p = 0.350, respectively). No correlation between the NOD2/CARD15 variants and clinical or laboratory findings (p > 0.05) was found. The frequencies of the NOD2/CARD15 gene mutations in the patients were similar to healthy control group. No association between clinical or laboratory findings and the NOD2/CARD15 gene mutations was observed.

Prevalence and Characteristics of Extra-intestinal Manifestations in a Large Cohort of Greek Patients with Inflammatory Bowel Disease

BACKGROUND AND AIMS

Extraintestinal manifestations [EIMs] are common in inflammatory bowel disease [IBD]. Data on epidemiology and risk factors of EIMs in IBD patients are limited. The aim of this study was to investigate the prevalence of EIMs in a large cohort of Greek IBD patients and identify risk factors for their development.

METHODS

The study population consisted of IBD patients, who were followed in eight tertiary Greek hospitals. Demographic and clinical characteristics of patients were analysed. The diagnosis of EIMs was based on standard criteria and on specialist consultation.

RESULTS

In total, 1860 IBD patients (1001 with Crohn's disease [CD], 859 with ulcerative colitis [UC]) were registered. Among them 615 [33.1%] exhibited at least one EIM; 238 patients [38.6%] developed an EIM before IBD diagnosis. An association between active IBD and presence of an EIM was established in 61.1% of the patients. Arthritic [peripheral arthritis], mucocutaneous [erythema nodosum], and ocular [episcleritis] were the most common manifestations. EIMs were more prevalent in females, patients with CD, smokers [for all p <0.0001], patients with extensive UC [p = 0.007], and patients with a previous appendectomy [p < 0.0001] or a major IBD-related surgery [p = 0.012].

CONCLUSIONS

About one-third of Greek IBD patients developed at least one EIM. Of those, more than one-third had their EIM diagnosed before IBD, and in about two-thirds it was related to disease activity. EIMs were more frequently present in females and patients with extensive UC in multivariate analysis.

Occult spondyloarthritis in inflammatory bowel disease

Spondyloarthritis (SpA) is a frequent extra-intestinal manifestation in patients with inflammatory bowel disease (IBD), although its real diffusion is commonly considered underestimated. Abnormalities in the microbioma and genetic predisposition have been implicated in the link between bowel and joint inflammation. Otherwise, up to date, pathogenetic mechanisms are still largely unknown and the exact influence of the bowel activity on rheumatic manifestations is not clearly explained. Due to evidence-based results of clinical studies, the interest on clinically asymptomatic SpA in IBD patients increased in the last few years. Actually, occult enthesitis and sacroiliitis are discovered in high percentages of IBD patients by different imaging techniques, mainly enthesis ultrasound (US) and sacroiliac joint X-ray examinations. Several diagnostic approaches and biomarkers have been proposed in an attempt to correctly classify and diagnose clinically occult joint manifestations and to define clusters of risk for patient screening, although definitive results are still lacking. The correct recognition of occult SpA in IBD requires an integrated multidisciplinary approach in order to identify common diagnostic and therapeutic strategies. The use of inexpensive and rapid imaging techniques, such as US and X-ray, should be routinely included in daily clinical practice and trials to correctly evaluate occult SpA, thus preventing future disability and worsening of quality of life in IBD patients.

Disease severity in familial cases of IBD

BACKGROUND

Phenotypic traits of familial IBD relative to sporadic cases are controversial, probably related to limited statistical power of published evidence.

AIM

To know if there are phenotype differences between familial and sporadic IBD, evaluating the prospective Spanish registry (ENEIDA) with 11,983 cases.

METHODS

5783 patients (48.3%) had ulcerative colitis (UC) and 6200 (51.7%) Crohn's disease (CD). Cases with one or more 1st, 2nd or 3rd degree relatives affected by UC/CD were defined as familial case.

RESULTS

In UC and CD, familial cases compared with sporadic cases had an earlier disease onset (UC: 33 years [IQR 25-44] vs 37 years [IQR 27-49]; p<0.0001); (CD: 27 years [IQR 21-35] vs 29 years [IQR 22-40]; p<0.0001), higher prevalence of extraintestinal immune-related manifestations (EIMs) (UC: 17.2% vs 14%; p=0.04); (CD: 30.1% vs 23.6%; p<0.0001). Familial CD had higher percentage of ileocolic location (42.7% vs 51.8%; p=0.0001), penetrating behavior (21% vs 17.6%; p=0.01) and perianal disease (32% vs 27.1%; p=0.003). Differences are not influenced by degree of consanguinity.

CONCLUSION

When a sufficiently powered cohort is evaluated, familial aggregation in IBD is associated to an earlier disease onset, more EIMs and more severe phenotype in CD. This feature should be taken into account at establishing predictors of disease course.

Current issues in pediatric inflammatory bowel disease-associated arthropathies

Joint involvement is the most common extraintestinal manifestation in children with inflammatory bowel disease (IBD) and may involve 16%-33% of patients at diagnosis or during follow-up. It is possible to distinguish asymmetrical, transitory and migrating arthritis (pauciarticular and polyarticular) and spondyloarthropathy (SpA). Clinical manifestations can be variable, and peripheral arthritis often occurs before gastrointestinal symptoms develop. The inflammatory intestinal pattern is variable, ranging from sub-clinical inflammation conditions, classified as indeterminate colitis and nodular lymphoid hyperplasia of the ileum, to Crohn’s disease or ulcerative colitis. Unlike the axial form, there is an association between gut inflammation and evolution of recurrent peripheral articular disease that coincides with a flare-up of intestinal disease. This finding seems to confirm a key role of intestinal inflammation in the pathogenesis of SpA. An association between genetic background and human leukocyte antigen-B27 status is less common in pediatric than n adult populations. Seronegative sacroiliitis and SpA are the most frequent forms of arthropathy in children with IBD. In pediatric patients, a correct therapeutic approach relies on the use of nonsteroidal antiinflammatory drugs, local steroid injections, physiotherapy and anti-tumor necrosis factor therapy (infliximab). Early diagnosis of these manifestations reduces the risk of progression and complications, and as well as increasing the efficacy of the therapy.

Extraintestinal manifestations and complications in IBD

More than one-third of patients with IBD are affected by extraintestinal manifestations or extraintestinal complications beyond the intestinal manifestation of the disease. The most common manifestations include arthropathies, mucocutaneous and ophthalmological manifestations, as well as conditions affecting the hepatobiliary system, both in Crohn's disease and ulcerative colitis. However, less frequent manifestations, such as pulmonary or neurological manifestations, should also be considered in patients with IBD. Several extraintestinal manifestations follow the course of the underlying intestinal activity, whereas others are independent from the intestinal inflammation. Extraintestinal complications such as iron-deficiency anaemia and osteoporosis are consequences of the intestinal disease or of disease-specific treatment. As extraintestinal manifestations and complications strongly influence quality of life, and to avoid severe complications, adequate treatment is mandatory in affected patients. We provide a comprehensive overview of different extraintestinal manifestations and complications, including their management, in patients with IBD.

Pathophysiology and role of the gastrointestinal system in spondyloarthritides

Inflammatory bowel disease (IBD) is a well-known extra-articular manifestation in spondyloarthritis (SpA); about 6.5% of patients with ankylosing spondylitis develop IBD during the course of the disease. The pathogenesis of both SpA and IBD is considered to be the result of a complex interplay between the host (genetic predisposition), the immune system and environmental factors, notably microorganisms, leading to a disturbed immune system and chronic inflammation. Over the past decade, the role of tumor necrosis factor inhibition (infliximab, etanercept, adalimumab, golimumab) in improving signs and symptoms and overall quality of life has been well documented in various forms of SpA. Future research will clarify the role of other potential targets.

Ubiquitination and phosphorylation in the regulation of NOD2 signaling and NOD2-mediated disease

The immune system is exquisitely balanced. It has the ability to effectively respond to and control infections while at the same time preventing inappropriate responses to self and environmental antigens. When this response goes awry, either through a failure to activate the immune response, or failure to terminate it, inflammatory pathology results. Posttranslational modifications (PTMs) such as ubiquitination and phosphorylation help ensure that the delicate balance underlying immune signal transduction is maintained. Ubiquitination and phosphorylation affect localization, activity, stability, and interactions of various components of the immune signal transduction machinery. Moreover, ubiquitination and phosphorylation are tightly linked, with one PTM affecting the other. Therefore, in order to find potential therapies for many immune-related pathologies, it is necessary to understand not only how the immune response is activated by ubiquitination and phosphorylation, but also how it is regulated by these PTMs at different stages of the response. An excellent system to study such activation and regulation is the NOD2 pathway. Dysregulation of NOD2 signaling is involved in the pathogenesis of a variety of inflammatory disorders including Crohn's disease, early onset sarcoidosis, and Blau syndrome. More recently NOD2 has been implicated in the development of autoimmune disease, allergy and asthma. This review will focus on what is currently known about how ubiquitination and phosphorylation regulate NOD2 signaling with particular emphasis on novel in vitro substrates which may serve as potential in vivo therapeutic targets for hyperactive NOD2 states. This article is part of a Special Issue entitled: Ubiquitin Drug Discovery and Diagnostics.

Rheumatological manifestations in inflammatory bowel disease

Rheumatological manifestations in inflammatory bowel disease (IBD) are frequent and include peripheral arthritis, axial involvement and peripheral enthesitis. Secondary osteoporosis and hypertrophic osteoarthropathy may also occur. Complications of IBD (e.g. septic arthritis) must be distinguished from sterile inflammation. Adverse effects of corticosteroid treatment, such as osteonecrosis, may also affect joints. Axial involvement ranges from low back pain to true ankylosing spondylitis. Human leukocyte antigen B27 is associated with axial involvement of IBD. Peripheral arthritis has been classified into two types. Type I is a pauciarticular, asymmetric usually non destructive arthritis affecting large joints and is usually associated with active bowel disease. Type II is a polyarthritis affecting small joints and tends to run a course independent of the bowel disease. Treatment of joint symptoms in IBD include sulphasalazine, azathioprine, methotrexate and glucocorticoids. Anti-tumor necrosis factor antibodies are effective in treating resistant or complicated Crohn's disease as well as peripheral arthritis and axial involvement.

The joint-gut axis in inflammatory bowel diseases

Inflammatory bowel diseases, Crohn's disease and ulcerative colitis, are associated with a variety of extraintestinal manifestations. The most common extraintestinal manifestation, articular involvement, occurs in 16% to 33% of inflammatory bowel disease patients. These arthropathies may increase morbidity, resulting in a worse quality of life compared with inflammatory bowel disease patients without arthropathies. Thus, arthropathies in inflammatory bowel diseases represent a major medical problem in these patients. Arthritis associated with inflammatory bowel diseases is one of the diseases captured under the umbrella of spondyloarthritis. Spondyloarthritis is a group of inflammatory diseases with overlapping features and is linked to Human Leukocyte Antigen-B27. Arthropathy in inflammatory bowel diseases is clinically divided into peripheral and axial involvement. Peripheral arthritis often flares with relapses of bowel disease resulting in a different treatment approach than axial arthritis in which the course is independent of inflammatory bowel disease activity. Definitions, prevalence, pathophysiology and treatment of the arthropathies commonly seen in inflammatory bowel diseases such as peripheral arthritis, dactylitis, enthesitis, arthralgia, sacroiliitis, inflammatory back pain and ankylosing spondylitis are summarized.

Extraintestinal manifestations of inflammatory bowel disease

The idiopathic inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, may be complicated by extraintestinal manifestations (EIMs) in up to 40% of patients. Reports suggest that almost every organ system may be affected. The EIMs are a significant cause of morbidity and may be particularly distressing for the patient. Recent attempts have been made to define the phenotype of IBD in patients of different ethnicities. These studies have highlighted potential racial variations in the prevalence of specific EIMs, findings that are perhaps not surprising given the influence of genetic factors in their pathogenesis. Certain EIMs are related to the activity of the bowel disease, and their management often involves careful monitoring while the IBD is brought under control. Other EIMs, however, typically run a course independent of the IBD activity, and specific, targeted treatments may be required, even including biologic agents such as infliximab.

The prevalence, clinical features and association of HLA-B27 in sacroiliitis associated with established Crohn's disease

BACKGROUND

Sacroiliitis is a recognized complication of Crohn's disease and may occur distinct from progressive ankylosing spondylitis (AS).

AIM

To estimate prospectively the prevalence of sacroiliitis in patients with established Crohn's disease, to characterize the clinical features and to correlate these with the presence of HLA-B27.

METHODS

All Crohn's disease patients under active follow-up of between 5 and 12 years duration were invited to participate. Patients underwent a clinical evaluation including symptom questionnaire, rheumatological examination and underwent HLA genotyping. Patients then underwent magnetic resonance imaging (MRI) of the sacroiliac joints. The clinical and radiological factors were correlated with HLA-B27 status.

RESULTS

56 patients underwent initial assessment and 44 had MRI scans. Seventeen of 44 (39%) patients had MRI evidence of sacroiliitis, of whom 5 fulfilled the criteria for AS. Symptoms of low back pain were elicited in a majority of these patients--11/17 (65%) compared to 3 of 27 (11%) patients with normal scans (P = 0.003). There were no differences in functional indices with the exception of patients with AS. HLA-B27 was present in seven patients, and all seven had MRI evidence of sacroiliitis, five had AS.

CONCLUSIONS

Sacroiliitis is common in patients with established Crohn's disease and in the majority of cases, patients have symptoms of inflammatory low back pain if questioned carefully. HLA-B27 is not associated with isolated sacroiliitis, but is associated with AS. However, possession of HLA-B27 appears to convey a very high risk of developing axial inflammation in Crohn's disease.

Clinical and genetic factors associated with sacroiliitis in Crohn's disease

BACKGROUND AND AIM

Radiographic sacroiliitis (SI), often asymptomatic, is considered the most frequent extra-intestinal manifestation (EIM) of Crohn's disease (CD). Data on the association of SI with other clinical features of CD are limited. Association of SI with CARD15 polymorphisms has recently been suggested. In a multicenter study, we investigated the association of SI in CD patients with clinical phenotypes, other EIM and CARD15 polymorphisms.

METHODS

Radiographs of the sacroiliac joints were taken in 251 CD patients from three Belgian university hospitals and scored by two blinded rheumatologists. Clinical features were obtained from medical records. Forty-three percent of patients carried at least one CARD15 polymorphism.

RESULTS

Sacroiliitis, defined as the presence of at least grade 2 unilateral changes, was diagnosed in 65 of the 244 scorable radiographs (27%). Only 16 of these patients were previously diagnosed with ankylosing spondylitis (AS). HLA-B27 positivity was observed in 53% of patients with AS and 7% of patients with radiographic SI. In univariate and multivariate analysis, associations between the presence of SI and peripheral arthritis (P = 0.005) and between AS and uveitis (P = 0.005) were found. No associations with other recorded clinical features or with CARD15 polymorphisms were observed.

CONCLUSION

We confirm the high prevalence of radiographic sacroiliitis in a multicenter CD cohort. Uveitis is only associated with AS whereas all patients with SI are more prone to develop peripheral arthritis during their disease course, suggesting similar pathogenetic mechanisms in the development of these EIM. The previously reported association between SI and CARD15 polymorphisms was not confirmed.

The intimate relationship between gut and joint in spondyloarthropathies

PURPOSE OF REVIEW

The aim of this article is to highlight recent progress in the combined joint and gut disease in spondyloarthropathies.

RECENT FINDINGS

A set of genes has been identified that are differentially expressed in the colon of spondyloarthropathy and Crohn's disease patients. Reduction of human leukocyte antigen B27 (HLA B27) misfolding by additional beta2-microglobulin in HLA B27 transgenic rats unexpectedly increased disease severity, with more similarities to spondyloarthropathies. By contrast, colitis disappeared.

SUMMARY

Human genomic studies combined with animal model research provide new clues concerning the common pathogenesis of spondyloarthropathy and Crohn's disease, further substantiating the unique relationship between gut and joint inflammation.

Relationship between clinical features of Crohn's disease and the risk of developing extraintestinal manifestations

OBJECTIVES

Crohn's disease is frequently associated with extraintestinal manifestations. The aim of this study was to evaluate the degree of association between the development of extraintestinal manifestations, the clinical forms of Crohn's disease according to the Vienna Classification and to the presence of several potential risk factors of the disease.

METHODS

One hundred and seventy-three consecutive Crohn's disease patients were studied. Sex, smoking habits, previous Crohn's disease-related surgery, family history of Crohn's disease, steroid dependency, steroid resistance and the presence of at least one mutant allele in any of the three considered variants of CARD15 gene were considered as potential risk factors. The Vienna Classification was applied, and the presence of extraintestinal manifestations was evaluated.

RESULTS

A total of 61 (35.3%) patients developed extraintestinal manifestations. They were more frequently seen in women than in men (41.1 vs. 26.7%), (odds ratio 1.92, 95% confidence interval: 0.99-3.70; P=0.05) and in steroid-dependent patients than in steroid responders (61.1 vs. 28.5%), (odds ratio 3.94, 95% confidence interval: 1.83-8.49; P<0.01). No relationship was found in general between the extraintestinal manifestations of Crohn's disease and smoking habits, previous Crohn's disease-related surgery, a family history of Crohn's disease, steroid resistance and CARD15 mutations. Such relationships were, however, detected for some individual extraintestinal manifestations as between both smoking habits (odds ratio 9.09, 95% confidence interval: 1.15-71.66; P<0.05) and the G908R CARD15 mutation (odds ratio 4.76, 95% confidence interval: 1.11-20.43; P<0.05), respectively, and erythema nodosum. Patients with any colonic involvement of Crohn's disease (L2+L3) suffered from extraintestinal manifestations of the disease more frequently than patients without colonic involvement (42.7 vs. 25.9%, respectively; odds ratio 2.12, 95% confidence interval: 1.10-4.07; P<0.05).

CONCLUSIONS

Female gender, steroid-dependency and colonic involvement are associated with the risk of developing extraintestinal manifestations of Crohn's disease.

Ankylosing spondylitis and bowel disease

Between 5 and 10% of cases of ankylosing spondylitis (AS) are associated with inflammatory bowel disease (IBD), either Crohn's disease or ulcerative colitis. A much larger percentage of AS patients have subclinical gut inflammation manifested either by endoscopic findings or by histology. The association with HLA-B27 is less strong in IBD-associated AS than in idiopathic AS, and there is evidence for an association between gut inflammation in AS with the Crohn's-disease-related CARD15 mutations. Despite the different genetics, the immunopathology suggests common inflammatory pathways in gut and joint inflammation in AS, and in gut inflammation in AS and IBD. Although this observation is of interest to unravel the pathophysiology of the disease, systematic screening of AS patients by ileocolonoscopy is not indicated in the absence of gut symptomatology as only a small proportion of AS patients with subclinical gut inflammation will develop overt IBD over time. Treatment of AS associated with IBD with non-steroidal anti-inflammatory drugs (NSAIDs) is problematic because of concerns of potential re-activation of IBD by NSAIDs. Major advances have been made in recent years with the establishment of anti-tumour necrosis factor (TNF) therapy in AS, the other spondyloarthritides and IBD. Anti-TNF agents are of particular relevance to AS patients with concomitant IBD who are at risk of exacerbation of the underlying bowel disease when treated with NSAIDs. In IBD, infliximab, unlike etanercept, is effective in treating clinical symptoms, inducing and maintaining remission, and mucosal healing. Adalimumab appears to be effective in treating both AS and IBD; however, official approval is pending. Currently, infliximab is the drug of choice for the treatment of patients with active AS associated with IBD.

Extraintestinal manifestations and complications in inflammatory bowel diseases

Crohn’s disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases (IBD) that often involve organs other than those of the gastrointestinal tract. These nonintestinal affections are termed extraintestinal symptoms. Differentiating the true extraintestinal manifestations of inflammatory bowel diseases from secondary extraintestinal complications, caused by malnutrition, chronic inflammation or side effects of therapy, may be difficult. This review concentrates on frequency, clinical presentation and therapeutic implications of extraintestinal symptoms in inflammatory bowel diseases. If possible, extraintestinal manifestations are differentiated from extraintestinal complications. Special attention is given to the more recently described sites of involvement; i.e. thromboembolic events, osteoporosis, pulmonary involvement and affection of the central nervous system.

Do host genetic traits in the bacterial sensing system play a role in the development of Chlamydia trachomatis-associated tubal pathology in subfertile women?

Background

In women, Chlamydia (C.) trachomatis upper genital tract infection can cause distal tubal damage and occlusion, increasing the risk of tubal factor subfertility and ectopic pregnancy. Variations, like single nucleotide polymorphisms (SNPs), in immunologically important host genes are assumed to play a role in the course and outcome of a C. trachomatis infection. We studied whether genetic traits (carrying multiple SNPs in different genes) in the bacterial sensing system are associated with an aberrant immune response and subsequently with tubal pathology following a C. trachomatis infection. The genes studied all encode for pattern recognition receptors (PRRs) involved in sensing bacterial components.

Methods

Of 227 subfertile women, serum was available for C. trachomatis IgG antibody testing and genotyping (common versus rare allele) of the PRR genes TLR9, TLR4, CD14 and CARD15/NOD2. In all women, a laparoscopy was performed to assess the grade of tubal pathology. Tubal pathology was defined as extensive peri-adnexal adhesions and/or distal occlusion of at least one tube.

Results

Following a C. trachomatis infection (i.e. C. trachomatis IgG positive), subfertile women carrying two or more SNPs in C. trachomatis PRR genes were at increased risk of tubal pathology compared to women carrying less than two SNPs (73% vs 33% risk). The differences were not statistically significant (P = 0.15), but a trend was observed.

Conclusion

Carrying multiple SNPs in C. trachomatis PRR genes tends to result in an aberrant immune response and a higher risk of tubal pathology following a C. trachomatis infection. Larger studies are needed to confirm our preliminary findings.

Chlamydia trachomatis-associated tubal factor subfertility: Immunogenetic aspects and serological screening

Chlamydia (C.) trachomatis female genital tract infections usually remain asymptomatic and untreated. Therefore, an adequate immune response, rather than antibiotic treatment, is essential to clear the pathogen. Most women will effectively clear C. trachomatis infections, but some will have persistent C. trachomatis infections, which may ascend to the upper genital tract and increase the risk of tubal factor subfertility. Pattern recognition receptors (PRRs) of the toll-like receptor (TLR) and nucleotide-binding oligomerization domain (NOD) families recognize C. trachomatis and initiate the immune response. Host immune factors are determinants of the course of C. trachomatis infections. Genetic variations in TLR and NOD genes may affect receptor function, leading to inadequate recognition of C. trachomatis, an inadequate immune response, and consequently an increased risk of persistence and late sequelae. For the risk assessment of tubal pathology in subfertile women, C. trachomatis immunoglobulin (Ig) G antibody testing (CAT) in serum is widely used. A positive CAT is indicative of a previous infection but not of a persistent infection. Measuring serological markers of persistence, of which C-reactive protein (CRP) seems promising, in CAT-positive women may identify a subgroup of subfertile women with persistent C. trachomatis infections and the highest risk of tubal pathology.

Extraintestinal manifestations of inflammatory bowel diseases

Inflammatory bowel diseases are associated with extraintestinal manifestations involving almost every organ system in the body. They occur in approximately 20% to 40% of patients with inflammatory bowel diseases. Immune-related and genetic mechanisms play an important role in the pathogenesis of these complications. Peripheral arthritis, erythema nodosum, and episcleritis respond to the treatment of the underlying intestinal inflammation, whereas axial arthropathy, pyoderma gangrenosum, and uveitis do not. Immunomodulator therapy, particularly with biologic agents has been shown to be effective in treating some of the extraintestinal manifestations. Early recognition and treatment are crucial in preventing major morbidity.

Extraintestinal manifestations in inflammatory bowel disease

Inflammatory bowel diseases (IBD) can be really considered to be systemic diseases since they are often associated with extraintestinal manifestations, complications, and other autoimmune disorders. Indeed, physicians who care for patients with ulcerative colitis and Crohn's disease, the two major forms of IBD, face a new clinical challenge every day, worsened by the very frequent rate of extraintestinal complications. The goal of this review is to provide an overview and an update on the extraintestinal complications occurring in IBD. Indeed, this paper highlights how virtually almost every organ system can be involved, principally eyes, skin, joints, kidneys, liver and biliary tracts, and vasculature (or vascular system) are the most common sites of systemic IBD and their involvement is dependent on different mechanisms.

Additional human β2-microglobulin curbs HLA–B27 misfolding and promotes arthritis and spondylitis without colitis in male HLA–B27–transgenic rats

OBJECTIVE

Ankylosing spondylitis and related spondylarthritides are associated with HLA-B27, and also with intestinal inflammation, by unknown mechanisms. The folded HLA-B27 molecule is a trimer of heavy chain, beta2-microglobulin (beta2m), and short peptide. However, B27 heavy chain has an unusual propensity to misfold and trigger the unfolded protein response (UPR). This study was initiated to test the hypothesis that B27 misfolding plays a role in the pathogenesis of spondylarthritis.

METHODS

Rats with high transgene copy numbers of HLA-B27 heavy chain together with human beta2m (Hubeta2m) spontaneously develop colitis, peripheral arthritis, and occasional spondylitis, and those with lower transgene copy numbers remain healthy. We crossed disease-prone and healthy HLA-B27/Hubeta2m-transgenic rat lines with a healthy line, 283-2, carrying only the Hubeta2m transgene. HLA-B27 assembly was assessed by pulse-chase analysis of B27 molecules, and UPR triggering was assessed by measuring BiP/Grp78 messenger RNA (mRNA) in splenic concanavalin A blasts. Surface expression of B27 and Hubeta2m was determined by flow cytometry. Disease manifestations were identified by clinical observation, histology, and measurement of cytokine mRNA.

RESULTS

The extra Hubeta2m from the 283-2 line significantly reduced B27 misfolding and UPR triggering. Unexpectedly, however, F1 male offspring of the healthy 21-3 line crossed with the 283-2 line showed a high prevalence, severity, and duration of arthritis and spondylitis, in the absence of colitis. The arthropathy showed many features characteristic of human spondylarthritis.

CONCLUSION

These results suggest that B27 misfolding is associated with intestinal inflammation, but that neither B27 misfolding nor intestinal inflammation is critical to the development of B27-associated arthropathy.

Radiologic case study. Seronegative spondyloarthropathy associated with Crohn's disease

Seronegative arthropathies are a heterogeneous group of arthropathic disorders with negative rheumatoid factors and varying association with the HLA-B27 phenotype. The distribution of involvement and pattern of presentation within this group is variable. However, these disorders share common features of aggressive erosions, bone density preservation, and proliferative bony response to inflammation. These features along with asymmetric involvement of the appendicular skeleton, sacroiliitis, and spine abnormalities usually allow differentiation from rheumatoid arthritis and other inflammatory arthritides based on imaging studies.

Caspase recruitment domain 15 mutations and rheumatic diseases

PURPOSE OF REVIEW

The purpose of this article is to review the foundational work and current developments on a group of rheumatic disorders associated with mutations in the caspase recruitment domain 15/nucleotide oligomerization domain 2 gene.

RECENT FINDINGS

To date, there are at least 10 arthritic conditions for which specific genetic mutations have been demonstrated. They include familial Mediterranean fever; tumor necrosis factor receptor associated periodic syndrome; hyper immunoglobulin D syndrome; neonatal onset multisystemic inflammatory disease; pyogenic arthritis pyoderma gangrenosum and acne; Muckle-Wells syndrome; familial cold autoinflammatory syndrome; immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome; Crohn's disease; and familial and sporadic sarcoid granulomatous arthritis. This review focuses on recent progress in the last two diseases and the caspase recruitment domain 15 genetic defects with which they are associated. Up to 50% of patients with familial granulomatous arthritis (Blau's syndrome), 90% of those with sporadic granulomatous arthritis (early-onset sarcoidosis), and 40% of individuals with Crohn's disease have documented mutations in the caspase recruitment domain 15 gene.

SUMMARY

Although histologically, Crohn's disease and familial and sporadic sarcoid granulomatous arthritis are distinct from rheumatoid arthritis because of the defining presence (albeit in not all cases) of non-caseating granulomata in the synovial and intestinal tissues, respectively, they still represent a promising model of both chronic synovitis and uveitis. In addition, once the actual mechanism is discovered by which defects of the caspase recruitment domain 15 gene product lead to chronic arthritis, it may uncover unsuspected biologic targets for therapeutics.

NOD-LRR PROTEINS: Role in Host-Microbial Interactions and Inflammatory Disease

Nods are cytosolic proteins that contain a nucleotide-binding oligomerization domain (NOD). These proteins include key regulators of apoptosis and pathogen resistance in mammals and plants. A large number of Nods contain leucine-rich repeats (LRRs), hence referred to as NOD-LRR proteins. Genetic variation in several NOD-LRR proteins, including human Nod2, Cryopyrin, and CIITA, as well as mouse Naip5, is associated with inflammatory disease or increased susceptibility to microbial infections. Nod1, Nod2, Cryopyrin, and Ipaf have been implicated in protective immune responses against pathogens. Together with Toll-like receptors, Nod1 and Nod2 appear to play important roles in innate and acquired immunity as sensors of bacterial components. Specifically, Nod1 and Nod2 participate in the signaling events triggered by host recognition of specific motifs in bacterial peptidoglycan and, upon activation, induce the production of proinflammatory mediators. Naip5 is involved in host resistance to Legionella pneumophila through cell autonomous mechanisms, whereas CIITA plays a critical role in antigen presentation and development of antigen-specific T lymphocytes. Thus, NOD-LRR proteins appear to be involved in a diverse array of processes required for host immune reactions against pathogens.