'MHC-I-opathy'-unified concept for spondyloarthritis and Behçet disease

Takayasu arteritis: a geographically distant but immunologically proximal MHC-I-opathy

Takayasu arteritis, a granulomatosis vasculitis with a pathogenesis that is poorly defined but known to be associated with HLA-B*52, shares many features with other MHC-I-opathies. In addition to the shared clinical features of inflammatory bowel diseases, cutaneous inflammation, and HLA-B*52, is shared association of an IL12B single- nucleotide polymorphism encoding the common IL-12 and IL-23 p40 subunit, which might affect not only type 17 cytokine responses, but also IFNγ and TNF production-the cardinal type 1 cytokines in granuloma formation. Considering the translational context of responses to TNF inhibition in Takayasu arteritis, in this Personal View we propose Takayasu arteritis as a type 1 MHC-I-opathy. Additionally, type 1 and type 17 T-cell immune responses show immune plasticity, which connects the overlapping features of Takayasu arteritis and spondyloarthritis spectrum disorders, providing a basis for shared anti-TNF responses, and points to p40 and IFNγ cytokine antagonism and potential selective CD8 T-cell repertoire ablation.

Features Associated with Response to Tonsillectomy in Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis Syndrome in Children

OBJECTIVE

To identify clinical features associated with response to tonsillectomy among children with periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome and to determine optimal management of children with continued episodes after tonsillectomy.

STUDY DESIGN

Patients with PFAPA seen at Vanderbilt University Children's Hospital and the National Institutes of Health (NIH) who underwent tonsillectomy were enrolled and queried regarding symptoms before and after surgery.

RESULTS

Ninety-seven subjects with PFAPA (43 Vanderbilt, 54 NIH) were followed for a median of 49 months following tonsillectomy. Nearly half of participants reported complete resolution of PFAPA episodes (65% at Vanderbilt and 35% at NIH), while 25% had less severe or frequent episodes, 23% had a period of remission with recurrence, and 4% had no change in episodes. By logistic regression, factors associated with a full response to tonsillectomy were episode resolution with glucocorticoid treatment, presence of exudative pharyngitis, absence of rash, and absence of arthralgia/myalgia during pre-tonsillectomy PFAPA flares. Among those requiring treatment for persistent flares post-tonsillectomy, 15/19 (79%) reported improvement with cimetidine or famotidine prophylaxis.

CONCLUSION

Tonsillectomy remains effective in improving PFAPA flares in most patients. However, unique episode features prior to tonsillectomy appear to be clinical predictors of response to tonsillectomy. Histamine receptor 2 antagonists like cimetidine were effective prophylactic agents for refractory cases post-tonsillectomy. Patients with incomplete response to tonsillectomy may represent a subset of PFAPA with unique factors affecting their pathogenesis.

Deficiency of Adenosine Deaminase 2 Masquerading as Behçet's Disease: Phenotypic Mimicry with HLA-B*51 Positivity

PURPOSE

Deficiency of adenosine deaminase 2 (DADA2) is a rare monogenic autoinflammatory disease resulting from biallelic loss-of-function mutations in ADA2 gene. It has variable clinical manifestations, some of which can mimic Behçet's disease (BD). Herein, we present a family of three siblings diagnosed with DADA2, two of whom were initially misdiagnosed as BD based on clinical phenotype including positive human leukocyte antigen B51 (HLA-B*51).

METHODS

Gene mutational analysis was performed by whole exome (WES) and Sanger sequencing.

RESULTS

We reported two siblings presented with recurrent oral ulcers, fever, arthritis, and skin lesions, alongside elevated inflammatory markers and HLA-B*51 positivity, leading to an initial misdiagnosis of BD. Genetic testing later revealed a homozygous ADA2 variant (c.139G > A p.Gly47Arg) in both siblings and their asymptomatic younger sister, confirming DADA2 diagnosis. Thereafter, we reviewed the literature to identify other patients misdiagnosed with BD but later found to have DADA2. This resulted in a cohort of 10 DADA2 patients, including our two reported siblings. The median time from symptoms onset to the final diagnosis of DADA2 was 7 years. All patients exhibited BD-like phenotype, except for uveitis, and 8 were HLA-B*51 positive, which likely contributed to the diagnostic confusion.

CONCLUSION

These findings highlight the broad clinical spectrum of DADA2, which can resemble BD, and suggest that HLA-B*51 positivity in DADA2 may further complicate diagnosis. Clinicians should maintain a high index of suspicion for DADA2 in early-onset BD-like cases, particularly without uveitis, or a family history of similar symptoms. Further studies are warranted to explore HLA-B*51 role in DADA2 phenotype.

Evaluation of inflammatory-thrombosis panel as a diagnostic tool for vascular Behçet's disease

OBJECTIVES

Vascular Behçet's disease (VBD) is prevalent in 40% of BD, but lacks laboratory biomarker for timely diagnosis. We aimed to establish a diagnostic panel for discerning VBD and non-VBD patients and identify hemostatic-thrombotic markers most related to VBD pathogenesis using machine learning algorithm.

OBJECTIVES

A total of 338 BD patients comprising 123 VBD and 215 non-VBD were enrolled. Twenty-six clinical and laboratory features selected from LassoCV were included in multiple classifier to choose the optimal model for VBD differentiation. The Shapley Additive exPlanations (SHAP) was employed to interpret the contribution of model features for VBD prediction. Logistic regression analysis and nomogram were conducted to screen risk factors of VBD.

RESULTS

Inflammatory (neutrophils%, NK cells, IL-6), hematological (hemoglobin, hemoglobin distribution width (HDW)) and thrombosis (activated partial thromboplastin clotting time (APTT), D-dimer) parameters were elevated in VBD. Then we chose top contributors from XGBoost model and performed ten-fold cross validation, the diagnostic accuracy of which exceeded 0.90. Utilizing SHAP method, we identified higher incidence of arterial thrombosis or aneurysm and deep vein thrombosis, upregulated NK cell count, HDW, APTT and D-dimer, downregulated reticulocyte%, B cell count, red blood cell distribution width, cellular hemoglobin (CH) and TNF-α would ultimately generate the phenotype of VBD. Severity, hemoglobin, mean corpuscular hemoglobin, CH, HDW, APTT and D-dimer were found as potential risk factors for vascular outcomes among BD.

RESULTS

Our study developed a well-performed model leveraging clinical and laboratory parameters for differentiating VBD. Inflammatory and thrombotic risk factors are potential contributors to VBD. Key Points • Inflammatory (neutrophils%, NK cells, IL-6), hematological (HGB, HDW) and thrombosis (APTT, D-dimer) parameters were elevated in VBD. • We firstly developed an inflammatory-thrombosis model as a diagnostic tool for VBD. • HGB, MCH, CH, HDW, APTT and D-dimer are potential risk factors for VBD.

Fast, Present and Future of the Concept of Spondyloarthritis

PURPOSE OF REVIEW

Axial spondyloarthritis (axSpA) is a rather prevalent chronic inflammatory rheumatic disease that affects already relatively young patients. It has been known better since the end of the nineteenth century but quite a lot has been learned since the early 60ies when the first classification (diagnostic) criteria for ankylosing spondylitis (AS) were agreed on. I have been part of many developments in the last 30 years, and I'm happy to have been able to contribute to the scientific progress in terms of diagnosis, imaging, pathophysiology and therapy. When I was asked to write a manuscript about the SpA concept I felt honored. Thus, the purpose of this extensive review was, on the one hand, to describe the history of AS and axSpA, and on the other hand, to reason about the concept and the gestalt of axSpA, and finally to deliver some ideas what future researchers could possibly do to further study the disease.

RECENT FINDINGS

The last 3 decades were full of innovations for both, classification and treatment of axSpA which also helped us to learn about the pathophysiology. Thus, TNFa, IL-17, IL-23 and Janus kinase are established targets to reduce inflammation. IL-17 and IL-23 are very special in that regard because they both work for psoriasis but only anti-IL-17 agents which don't work in IBD are approved for axSpA, while IL 23 inhibitors are approved for both, psoriasis and IBD, but they don't work in axSpA. New imaging techniques such as low dose CT and synthetic MRI are likely to improve the detection of both active and structural lesions of axSpA. This manuscript tries to describe the most important findings about axSpA. The main aim of research remains to discover the pathophysiology and to further improve treatment options in order to reduce and abolish inflammation and prevent new bone formation to increase the quality of life of our patients. The differences between male and female disease and the role of the immune system in axSpA are now the main challenges, and the role of special T-cell receptors seem to deserve special interest.

Juvenile Behçet syndrome: a contemporary view and differential diagnosis in pediatric practice

PURPOSE OF REVIEW

This review aims to provide a comprehensive and contemporary overview of juvenile Behçet syndrome (jBS), highlighting its clinical manifestations, diagnostic challenges, and treatment strategies.

RECENT FINDINGS

Behçet syndrome, with its intricate etiopathogenesis and diverse clinical phenotypes, is more aptly classified as a syndrome than a single disease. Its heterogeneous nature requires a broad diagnostic approach and sophisticated differential diagnosis capabilities. The relatively rare occurrence of Behçet syndrome, combined with incomplete clinical presentations and overlapping differential diagnoses, presents significant diagnostic challenges, particularly in pediatric cases. Nevertheless, substantial progress has been made in treatment, especially in managing inflammatory components and preventing complications. Juvenile patients, given their developmental stage, require distinct therapeutic strategies compared to adults, with careful consideration of treatment side effects on growth and psychosocial development.

SUMMARY

To ensure early identification of jBS, it is imperative to refine and develop diagnostic criteria specifically tailored to pediatric populations. With a deeper understanding of the disease mechanisms, treatment protocols should be designed to address the developmental, psychosocial, and individual needs of patients, aiming to minimize long-term side effects. Additionally, comprehensive studies considering age, sex, and ethnic differences are necessary to fill gaps in the literature and resolve existing inconsistencies.

Use of Mendelian randomization to assess the causal status of modifiable exposures for rheumatic diseases

The explosion in Mendelian randomization (MR) publications is hard to ignore and shows no signs of slowing. Clinician readers, who may not be familiar with jargon-ridden methods, are expected to discern the good from the many low-quality studies that make overconfident claims of causality or stretch the plausibility of what MR can investigate. We aim to equip readers with foundational concepts, contextualized using examples in rheumatology, to appraise the many MR papers that are or will appear in their journals. We highlight the importance of assessing whether exposures are under plausibly specific genetic influence, whether the hypothesized causal pathways make biological sense, and whether results stand up to replication and use of control outcomes. Quality of research can vary substantially using MR as with any design, and all methods have inherent limitations. MR studies have provided and can still contribute valuable insights in the context of evidence triangulation.

Systemic auto-inflammatory manifestations in patients with spondyloarthritis

OBJECTIVES

(1) characterizing a group of spondyloarthritis (SpA) patients with systemic auto-inflammatory symptoms (S-SpA); (2) comparing SpA features with and without auto-inflammatory symptoms; (3) comparing the auto-inflammatory features of S-SpA and Still's disease (SD).

METHODS

Retrospective observational study. Clinical data of adult and pediatric patients with S-SpA, SD or SpA were collected retrospectively and analyzed.

RESULTS

Forty-one subjects with S-SpA, 39 with SD and 42 with SpA were enrolled. The median latency between systemic and articular manifestations in S-SpA was 4.4 (IQR: 7.2) years. S-SpA and SpA had similar frequency of peripheral arthritis and enthesitis (N.S.), while tenosynovitis was more frequent (P=0.01) and uveitis less frequent (P<0.01) in S-SpA. MRI showed signs of sacroiliac inflammation and damage in both S-SpA and SpA equally (N.S.). S-SpA patients had less corner inflammatory lesions (P<0.05) and inflammation at the facet joints (P<0.01), more interspinous enthesitis (P=0.01) and inter-apophyseal capsulitis (P<0.01). Compared to SD, S-SpA patients had lower-grade fever (P<0.01), less rash (P<0.01) and weight loss (P<0.05), but more pharyngitis (P<0.01), gastrointestinal symptoms (P<0.01) and chest pain (P<0.05). ESR, CRP, WBC, ANC, LDH tested higher in SD (P<0.01). Resolution of systemic symptoms was less frequent in S-SpA than SD on corticosteroid (P<0.01) and methotrexate (P<0.05) treatment. When considering all SD patients, a complete response to corticosteroids in the systemic phase significantly reduced the likelihood of developing SpA (OR=0.06, coefficient -2.87 [CI: -5.0 to -0.8]).

CONCLUSIONS

SpA should be actively investigated in patients with auto-inflammatory manifestations, including undifferentiated auto-inflammatory disease and SD.

A review of the advances in understanding the genetic basis of spondylarthritis and emerging clinical benefit

Spondyloarthropathies (SpA), including ankylosing spondylitis (AS) and psoriatic arthritis (PsA), have been shown to have a substantial genetic predisposition based on heritability estimates derived from family studies and genome-wide association studies (GWAS). GWAS have uncovered numerous genetic loci associated with susceptibility to SpA, with significant associations to human leukocyte antigen (HLA) genes, which are major genetic risk factors for both AS and PsA. Specific loci differentiating PsA from cutaneous-only psoriasis have been identified, though these remain limited. Further research with larger sample sizes is necessary to identify more PsA-specific genetic markers. Current research focuses on translating these genetic insights into clinical applications. For example, polygenic risk scores are showing promise for the classification of disease risk and diagnosis and future research should focus on refining these risk assessment tools to improve clinical outcomes for individuals with SpA. Addressing these challenges will help integrate genetic testing into patients care and impact clinical practice.

Enthesitis as an initial presentation of vascular Behçet's syndrome: a case-based review

Enthesitis is a characteristic manifestation of spondyloarthropathy (SpA). Historically, Behçet's syndrome (BS) was classified within SpA. Although they are now classified separately, the association between BS and SpA remains controversial. The concept of MHC-I (major histocompatibility complex class I)-opathy has been proposed based on the overlap in immunopathological mechanisms among diseases associated with human leukocyte antigen (HLA) class I. Enthesitis is a frequent complication in patients with BS who also have acne and arthritis. However, information regarding enthesitis in patients with BS without arthritis (BS-WA) is limited. Herein, we report a case of vascular BS complicated by enthesitis. In this case, heel pain was the dominant symptom at presentation. Laboratory tests revealed chlamydia antibody positivity, leading to a tentative diagnosis of reactive arthritis. Despite treatment, C-reactive protein (CRP) levels remained elevated. Imaging revealed numerous aneurysmal lesions in the large vessels. Based on these findings and other symptoms, patient was diagnosed with vascular BS. He tested positive for HLA-B15 and HLA-B46, which are associated with peripheral SpA. Subsequent remission induction therapy for BS was effective and the patient was discharged without complications. Our case and a literature review suggest that there exists a subgroup of BS-WA with a complication of enthesitis, possibly belonging to the spectrum of MHC-I-opathies. It is important to consider BS as a differential diagnosis in patients presenting with enthesitis and to conduct a precise medical history review regarding the symptoms of BS.

Genetically Proxied Interleukin-13 Inhibition Is Associated With Risk of Psoriatic Disease: A Mendelian Randomization Study

OBJECTIVE

Inhibitors of the interleukin 13 (IL-13) pathway, such as dupilumab, are licensed for atopic dermatitis and asthma. Adverse events resembling psoriatic disease after dupilumab initiation have been reported, but evidence is limited to case reports with uncertain causality. We aimed to investigate whether genetically mimicked IL-13 inhibition (IL-13i) is associated with risk of psoriatic arthritis (PsA) and psoriasis.

METHODS

We instrumented IL-13i using a protein-coding variant in the IL13 gene, rs20541, that is associated with circulating eosinophil count (biomarker of IL-13i) at genome-wide significance in a study of 563,946 individuals. Outcome genetic data were taken from studies of PsA, psoriasis, and related spondyloarthritis traits in up to 10,588 cases and 209,287 controls. Colocalization analysis was performed to examine genetic confounding. We additionally used circulating IgE as a biomarker to test whether associations were replicated, both in the test and in an independent genetic dataset. We also replicated analyses using individual-level data from the UK Biobank.

RESULTS

Genetically proxied IL-13i was associated with increased risk of PsA (odds ratio [OR] 37.39; 95% confidence interval [95% CI] 11.52-121.34; P = 1.64 × 10-9) and psoriasis (OR 20.08; 95% CI 4.38-92.01; P = 1.12 × 10-4). No consistent associations were found for Crohn disease, ulcerative colitis, ankylosing spondylitis, or iritis. Colocalization showed no strong evidence of genetic confounding for psoriatic disease. Results were replicated using circulating IgE for the exposure, using independent outcome data and using individual-level data.

CONCLUSION

We provide supportive genetic evidence that IL-13i is linked to increased risk of PsA and psoriasis. Physicians prescribing IL-13 inhibitors should be vigilant for these adverse events.

Clinical profiling, treatment characteristics and outcome in Behcet's Disease (BD)-A retrospective cohort study from Karnataka Rheumatology Association (KRA)

BACKGROUND

Behcet's disease (BD) has a heterogeneous and unpredictable phenotype that differs in various geographical areas.

OBJECTIVE

To describe the clinical phenotype & outcome of Behcet's disease(BD) from Karnataka, India and compare them with large cohorts from endemic regions.

METHODS

Databases of practising rheumatologists from Karnataka were reviewed to retrieve clinical characteristics, course of illness, prescribing information and outcome at last follow-up of patients clinically diagnosed as BD. The classification criteria, namely revised International criteria for Behcet's disease (rICBD) and International study group (ISG) criteria were applied. Outcome was defined as complete or partial remission, persistent disease or relapse.

RESULTS

We included 72 patients, equal gender distribution and mean age 37.4 ± 12.8 years from 8 rheumatology centres. Commonest presentations were recurrent oral aphthosis 58(80.6%), genital ulcers 36(50%) and ocular manifestations 40(55.6%). Three-quarters [51/72(70.8%)] fulfilled rICBD criteria whereas only half [36/72(50%)] fulfilled ISG criteria. Apart from glucocorticoids [53/72(73.6%)], frequently prescribed therapies were colchicine 39(54.2%) and azathioprine 35(48.6%). Eleven-patients received biologics(anti-TNF-α) and JAK inhibitors to treat severe organ involvement. HLA-B*51 and pathergy tests were positive in 27/45(60%) and 12/34(35.3%) patients respectively. Outcomes were documented in 94.4%(68/72) patients at median follow-up of 24 (12;36) months. Majority [46/68(67.6%)] had complete remission, 17/68(25%) had partial remission, 4/68(5.9%) had persistent while 1/68(1.5%) had relapsing course.

CONCLUSION

Majority of BD patients had orogenital aphthosis and ocular manifestations and an excellent response to treatment. Key Points • In our region, Behçet's Disease primarily manifests with recurrent oral aphthae and ocular involvement, with comparatively lower incidence of severe genital ulcers and neurological involvement than in endemic regions. • Apart from glucocorticoids, colchicine and azathioprine are the most commonly used agents. Biologics and JAK inhibitors are prescribed infrequently, primarily in cases of severe organ involvement. • A significant proportion of patients achieved either complete or partial remission during follow-up, with no observed mortality suggesting a milder disease course and better outcome compared to endemic regions. • Gender, HLA-B*51 status, and pathergy response did not exert any significant influence on the clinical profile or outcome in BD patients in Karnataka.

Regulatory role of the lncRNAs MIAT and PVT1 in Behçet's disease through targeting miR-93-5p and miR-124-3p

BACKGROUND

Noncoding RNAs play pivotal roles in the process of autoimmune diseases. However, the definite contributions of these molecules to Behçet's disease (BD) are still unknown. This study aimed to explore the clinical value of a novel competing endogenous (ce) RNA network in the pathogenesis of BD and to assess its use in primary diagnosis.

METHODS

Bioinformatic analysis was applied to construct a BD-related ceRNA network: lncRNA (MIAT and PVT1)-miRNA (miR-93-5p and miR-124-3p)-mRNA (SOD-2 and MICA). Blood was obtained from 70 BD patients and 30 healthy subjects, and the serum expression of the tested RNAs was estimated via quantitative real-time PCR (qPCR). Serum tumor necrosis factor-alpha (TNF-α) levels were also determined. The associations between these RNAs were further analyzed, and receiver operating characteristic (ROC) curve and logistic regression analyses were employed to validate their diagnostic and prognostic values.

RESULTS

The expression levels of the lncRNAs PVT1 and miR-93-5p were significantly increased, whereas those of the lncRNAs MIAT and miR-124-3p, as well as those of the SOD-2 and MICA mRNAs, were significantly decreased in BD patients compared with controls. BD patients had significantly higher serum TNF-α levels than controls did. ROC curve analysis indicated that the selected RNAs could be candidate diagnostic biomarkers for BD. Moreover, the highest diagnostic efficiency was achieved with the combination of MIAT and miR-93-5p or PVT1 and miR-124-3p with either SOD-2 or MICA. Logistic regression analysis revealed that all RNA expression levels could be predictors for BD.

CONCLUSION

Mechanistically, our research revealed a novel ceRNA network that is significantly disrupted in BD. The findings reported herein, highlight the noncoding RNA-molecular pathways underlying BD and identify potential targets for therapeutic intervention. These insights will likely be applicable for developing new strategies for the early diagnosis, management and risk assessment of BD as well as the design of novel preventive measures. Trial registration The protocol for the clinical studies was approved by Cairo University's Faculty of Pharmacy's Research Ethics Committee (approval number: BC 3590).

How underappreciated autoinflammatory (innate immunity) mechanisms dominate disparate autoimmune disorders

Historically inflammation against self was considered autoimmune which stems back to the seminal observations by Ehrlich who described serum factors, now known to be autoantibodies produced by B lineage cells that mediate "horror autotoxicus". The 20th century elucidation of B- and T-cell adaptive immune responses cemented the understanding of the key role of adaptive immune responses in mediating pathology against self. However, Mechnikov shared the Nobel Prize for the discovery of phagocytosis, the most rudimentary aspect of innate immunity. Fast forward some 100 years and an immunogenetic understanding of innate immunity led to the categorising of innate immunopathology under the umbrella term 'auto inflammation' and terminology such as "horror autoinflammaticus" to highlight the schism from the classical adaptive immune understanding of autoimmunity. These concepts lead to calls for a two-tiered classification of inflammation against self, but just as innate and adaptive immunity are functionally integrated, so is immunopathology in many settings and the concept of an autoimmune to autoinflammation continuum emerged with overlaps between both. Herein we describe several historically designated disorders of adaptive immunity where innate immunity is key, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) where the immunopathology phenotype is strongly linked to major histocompatibility complex (MHC) class II associations and responds to drugs that target T-cells. We also consider MHC-I-opathies including psoriasis and Behcet's disease(BD) that are increasingly viewed as archetype CD8 T-cell related disorders. We also briefly review the key role of barrier dysfunction in eczema and ulcerative colitis (UC) where innate tissue permeability barrier dysfunction and microbial dysbiosis contributes to prominent adaptive immune pathological mechanisms. We also highlight the emerging roles of intermediate populations of lymphocytes including gamma delta (γδ) and mucosal-associated invariant T (MAIT) cells that represent a blend of adaptive immune plasticity and innate immune rapid responders that may also determine site specific patterns of inflammation.

Looking back on 51 years of the Carol Nachman Prize in Rheumatology-significance for the field of spondyloarthritis research

The city and casino of Wiesbaden, capital of the German state Hessen, have endowed the Carol Nachman Prize to promote research work in the field of rheumatology since 1972. The prize, endowed with 37,500 €, is the second highest medical award in Germany and serves to promote clinical, therapeutic, and experimental research work in the field of rheumatology. In June 2022, the 50-year anniversary was celebrated. In the symposium preceding the award ceremony, an overview was given on the significance of spondyloarthritis for the work of the awardees in the past 30 years. This overview has now been put together to inform the interested community of the work performed, including the opinion of the awardees regarding what they consider to be their most important contribution.

The safety and efficacy of TNF inhibitors in patients with Behçet's disease: Retrospective study from eastern Turkey

OBJECTIVE

We aimed to evaluate the clinical features, disease course, and associated factors for outcome in severe/refractory BD patients receiving TNF-i treatment.

MATERIAL AND METHODS

This retrospective study was conducted by reviewing medical records from a tertiary referral center in Van province in Eastern Turkey. Data were obtained from patients' charts followed up between June 2019 and June 2022.

RESULTS

We included 469 BD patients (59.3% male) whose 80 patients (17%) received TNF-i treatment in the study. The mean ± standard deviation of the patient age was 36.7 ± 10.1 years and the median (IQR) disease duration was 12 (12) years. IFX and ADAwere initiated in 67.5% (n = 54) and 32.5% (n = 26) patients, respectively. Overall and first-line retention rates of TNF-i were 84.7% and 92.6% for IFX and 83.3% and 80.8% for ADA, respectively. IFX was discontinued in 9 patients which were in 2 patients due to allergic reaction and tuberculosis, 3 patients for inefficacy, one patient for heart failure, and one patient for orbital zona. Although no serious adverse event was observed with ADA, 5 patients switched to IFX due to inefficacy. Overall, 72 patients (90%) resumed TNF-i at the end of the study; TNF-i was discontinued in 3 patients (3.8%) due to severe adverse events and in 5 patients (6.2%) with prolonged remission.

CONCLUSION

In our study, no case of death was observed in TNF-i receiving patients. Most patients achieved attack-free and CS-free disease and retained TNF-i treatment. TNF inhibitors appear to be safe and effective in patients with severe/refractory Behçet's disease.

Ocular Manifestations in Juvenile Behçet's Disease: A Registry-Based Analysis from the AIDA Network

INTRODUCTION

This study aims to characterize ocular manifestations of juvenile Behçet's disease (jBD).

METHODS

This was a registry-based observational prospective study. All subjects with jBD from the Autoinflammatory Diseases Alliance (AIDA) Network BD Registry showing ocular manifestations before 18 years were enrolled.

RESULTS

We included 27 of 1000 subjects enrolled in the registry (66.7% male patients, 45 affected eyes). The median (interquartile range [IQR]) age at ocular involvement was 14.2 (4.7) years. Uveitis affected 91.1% of eyes (anterior 11.1%, posterior 40.0%, panuveitis 40.0%), retinal vasculitis 37.8% and other manifestations 19.8%. Later onset (p = 0.01) and male predominance (p = 0.04) characterized posterior involvement. Ocular complications occurred in 51.1% of eyes. Patients with complications had earlier onset (p < 0.01), more relapses (p = 0.02) and more prolonged steroidal treatment (p = 0.02). The mean (standard deviation [SD]) central macular thickness (CMT) at the enrolment and last visit was 302.2 (58.4) and 293.3 (78.2) μm, respectively. Fluorescein angiography was pathological in 63.2% of procedures, with a mean (SD) Angiography Scoring for Uveitis Working Group (ASUWOG) of 17.9 (15.5). At the last visit, ocular damage according to the BD Overall Damage Index (BODI) was documented in 73.3% of eyes. The final mean (SD) best corrected visual acuity (BCVA) logMAR was 0.17 (0.47) and blindness (BCVA logMAR < 1.00 or central visual field ≤ 10°) occurred in 15.6% of eyes. At multivariate regression analysis, human leukocyte antigen (HLA)-B51 + independently predicted a + 0.35 change in the final BCVA logMAR (p = 0.01), while a higher BCVA logMAR at the first assessment (odds ratio [OR] 5.80; p = 0.02) independently predicted blindness.

CONCLUSIONS

The results of this study may be leveraged to guide clinical practice and future research on this rare sight-threatening condition.

Sex-specific circulating unconventional neutrophils determine immunological outcome of auto-inflammatory Behçet's uveitis

Neutrophils are the most abundant immune cells that first respond to insults in circulation. Although associative evidence suggests that differences in neutrophils may be linked to the sex-specific vulnerability of inflammatory diseases, mechanistic links remain elusive. Here, we identified extensive sex-specific heterogeneity in neutrophil composition under normal and auto-inflammatory conditions at single-cell resolution. Using a combination of single-cell RNA sequencing analysis, neutrophil-specific genetic knockouts and transfer experiments, we discovered dysregulation of two unconventional (interferon-α responsive and T cell regulatory) neutrophil subsets leading to male-biased incidence, severity and poor prognosis of auto-inflammatory Behçet's uveitis. Genome-wide association study (GWAS) and exosome study revealed that male-specific negative effects of both genetic factors and circulating exosomes on unconventional neutrophil subsets contributed to male-specific vulnerability to disease. Collectively, our findings identify sex-specifically distinct neutrophil subsets and highlight unconventional neutrophil subsets as sex-specific therapeutic targets to limit inflammatory diseases.

Frequency and the effects of spondyloarthritis-spectrum disorders on the clinical course and management of Takayasu arteritis: an observational retrospective study

OBJECTIVES

Extravascular findings of Takayasu arteritis (TAK) often share features with the spondyloarthritis (SpA) spectrum of disorders. However, the characteristics of this overlap and its effect on the vascular manifestations of TAK are not fully known. Therefore, we aimed to investigate the frequency of SpA-related features in TAK patients.

MATERIAL AND METHODS

In this observational retrospective study, 350 patients with TAK classified according to ACR 1990 criteria, from 12 tertiary rheumatology clinics, were included and evaluated for the presence of axSpA, IBD, or psoriasis. Demographic, clinical features, angiographic involvement patterns, disease activity, and treatments of TAK patients with or without SpA were analyzed.

RESULTS

Mean age was 45.5 ± 13.6 years and mean follow-up period was 76.1 ± 65.9 months. Among 350 patients, 31 (8.8%) had at least one additional disease from the SpA spectrum, 8 had IBD, 8 had psoriasis, and 20 had features of axSpA. In the TAK-SpA group, TAK had significantly earlier disease onset, compared to TAK-without-SpA (p = 0.041). SpA-related symptoms generally preceded TAK symptoms. Biological treatments, mostly for active vasculitis, were higher in the TAK-SpA group (70.9%) compared to TAK-without-SpA (27.9%) (p < 0.001). Vascular involvements were similar in both.

CONCLUSION

Our study confirmed that diseases in the SpA spectrum are not rare in TAK. Vascular symptoms appeared earlier in such patients, and more aggressive therapy with biological agents was required in the TAK-SpA group, suggesting an association between TAK and SpA spectrum. Key Points • The pathogenesis of Takayasu arteritis is mediated by an MHC class I alelle (HLA-B*52), similar to spondyloarthritis-disorders. • Extravascular findings of Takayasu arteritis are in the spectrum of spondyloarthritis disease. • This frequent coexistence between Takayasu arteritis and spondyloarthritic disorders suggests a relationship rather than a coincidence.

IL-23 past, present, and future: a roadmap to advancing IL-23 science and therapy

Interleukin (IL)-23, an IL-12 cytokine family member, is a hierarchically dominant regulatory cytokine in a cluster of immune-mediated inflammatory diseases (IMIDs), including psoriasis, psoriatic arthritis, and inflammatory bowel disease. We review IL-23 biology, IL-23 signaling in IMIDs, and the effect of IL-23 inhibition in treating these diseases. We propose studies to advance IL-23 biology and unravel differences in response to anti-IL-23 therapy. Experimental evidence generated from these investigations could establish a novel molecular ontology centered around IL-23-driven diseases, improve upon current approaches to treating IMIDs with IL-23 inhibition, and ultimately facilitate optimal identification of patients and, thereby, outcomes.

Novel genetic variants of HLA gene associated with Thai Behcet's disease (BD) patients using next generation sequencing technology

Behçet's disease (BD) manifests as an autoimmune disorder featuring recurrent ulcers and multi-organ involvement, influenced by genetic factors associated with both HLA and non-HLA genes, including TNF-α and ERAP1. The study investigated the susceptible alleles of both Class I and II molecules of the HLA gene in 56 Thai BD patients and 192 healthy controls through next-generation sequencing using a PacBio kit. The study assessed 56 BD patients, primarily females (58.9%), revealing diverse manifestations including ocular (41.1%), vascular (35.7%), skin (55.4%), CNS (5.4%), and GI system (10.7%) involvement. This study found associations between BD and HLA-A*26:01:01 (OR 3.285, 95% CI 1.135-9.504, P-value 0.028), HLA-B*39:01:01 (OR 6.176, 95% CI 1.428-26.712, P-value 0.015), HLA-B*51:01:01 (OR 3.033, 95% CI 1.135-8.103, P-value 0.027), HLA-B*51:01:02 (OR 6.176, 95% CI 1.428-26.712, P-value 0.015), HLA-C*14:02:01 (OR 3.485, 95% CI 1.339-9.065, P-value 0.01), HLA-DRB1*14:54:01 (OR 1.924, 95% CI 1.051-3.522, P-value 0.034), and HLA-DQB1*05:03:01 (OR 3.00, 95% CI 1.323-6.798, P-value 0.008). However, after Bonferroni correction none of these alleles were found to be associated with BD. In haplotype analysis, we found a strong linkage disequilibrium in HLA-B*51:01:01, HLA-C*14:02:01 (P-value 0.0, Pc-value 0.02). Regarding the phenotype, a significant association was found between HLA-DRB1*14:54:01 (OR 11.67, 95% CI 2.86-47.57, P-value 0.001) and BD with ocular involvement, apart from this, no distinct phenotype-HLA association was documented. In summary, our study identifies specific HLA associations in BD. Although limited by a small sample size, we acknowledge the need for further investigation into HLA relationships with CNS, GI, and neurological phenotypes in the Thai population.

Role of non-coding RNAs and exosomal non-coding RNAs in vasculitis: A narrative review

A category of very uncommon systemic inflammatory blood vessel illnesses known as vasculitides. The pathogenesis and etiology of vasculitis are still poorly known. Despite all of the progress made in understanding the genetics and causes behind vasculitis, there is still more to learn. Epigenetic dysregulation is a significant contributor to immune-mediated illnesses, and epigenetic aberrancies in vasculitis are becoming more widely acknowledged. Less than 2 % of the genome contains protein-encoding DNA. Studies have shown that a variety of RNAs originating from the non-coding genome exist. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) have attracted the most attention in recent years as they are becoming more and more important regulators of different biological processes, such as diseases of the veins. Extracellular vehicles (EVs) such as exosomes, are membrane-bound vesicular structures that break free either during programmed cell death, such as apoptosis, pyroptosis, and necroptosis or during cell activation. Exosomes may be involved in harmful ways in inflammation, procoagulation, autoimmune reactions, endothelial dysfunction/damage, intimal hyperplasia and angiogenesis, all of which may be significant in vasculitis. Herein, we summarized various non-coding RNAs that are involved in vasculitides pathogenesis. Moreover, we highlighted the role of exosomes in vasculitides.

The Role of Aminopeptidase ERAP1 in Human Pathology-A Review

Aminopeptidases are a group of enzymatic proteins crucial for protein digestion, catalyzing the cleavage of amino acids at the N-terminus of peptides. Among them are ERAP1 (coding for endoplasmic reticulum aminopeptidase 1), ERAP2 (coding for endoplasmic reticulum aminopeptidase 2), and LNPEP (coding for leucyl and cystinyl aminopeptidase). These genes encoding these enzymes are contiguous and located on the same chromosome (5q21); they share structural homology and functions and are associated with immune-mediated diseases. These aminopeptidases play a key role in immune pathology by cleaving peptides to optimal sizes for binding to the major histocompatibility complex (MHC) and contribute to cellular homeostasis. By their ability to remove the extracellular region of interleukin 2 and 6 receptors (IL2, IL6) and the tumor necrosis factor receptor (TNF), ERAP1 and ERAP2 are involved in regulating the innate immune response and, finally, in blood pressure control and angiogenesis. The combination of specific genetic variations in these genes has been linked to various conditions, including autoimmune and autoinflammatory diseases and cancer, as well as hematological and dermatological disorders. This literature review aims to primarily explore the impact of ERAP1 polymorphisms on its enzymatic activity and function. Through a systematic examination of the available literature, this review seeks to provide valuable insights into the role of ERAP1 in the pathogenesis of various diseases and its potential implications for targeted therapeutic interventions. Through an exploration of the complex interplay between ERAP1 and various disease states, this review contributes to the synthesis of current biomedical research findings and their implications for personalized medicine.

A strategy towards disentangling treatment refractory from misdiagnosed axial Spondyloarthritis

Axial spondyloarthritis (axSpA) encompasses radiographic axial SpA (r-axSpA), formally designated as ankylosing spondylitis (AS) and non-radiographic axial SpA (nr-axSpA). The advent of MRI permitted the description of the "pre-radiographic" (nr-AxSpA) stage characterized by bone marrow oedema lesions, histologically an osteitis, not yet visible on X-rays. Most subjects with a diagnosis of nr-axSpA do not progress to r-axSpA and the risk of misdiagnosis of nr-axSpA is considerable because back pain related to malalignment, degenerative conditions or biomechanical stress including intense exercise may lead to positive MRI scans. Even when nr-axSpA or r-axSpA are accurately diagnosed only about 40-50% achieve the ASAS40 responses with licensed therapies. It is likely that spinal enthesitis/osteitis leading to structural damage and associated damage contributes to post inflammatory disc territory secondary pain responses. Things are complicated as the concept of refractory axSpA itself is not well defined since there is no gold standard test to capture the full burden of inflammatory disease and, in any event, MRI has not been systematically applied. Nevertheless, there is sufficient evidence to borrow from the refractory rheumatoid arthritis field to propose two types of refractory axial SpA- a persistent inflammatory refractory ax-SpA (PIRaxSpA) and non-inflammatory refractory ax-SpA (NIRaxSpA). Both axSpA refractoriness and misdiagnosis need careful considerations when evaluating treatment failure. The immunological basis for axSpA immunotherapeutics non-responses is still rudimentary beyond the knowledge of HLA-B27 positivity status, CRP elevation, and MRI bone oedema that represents osteitis being equated with responder status.

[Autoimmunity in rheumatology: A review]

Autoimmunity and autoinflammation, co-potentiating pathological processes, are considered within the "immune-inflammatory" continuum (continuity with a variety of elements), reflecting the close relationship between the innate and acquired immune responses. Autoimmunity is the leading pathogenetic mechanism for a specific type of human chronic inflammatory disorders - autoimmune diseases, affecting more than 10% of people in the general population. Advances in molecular biology, pharmacogenetics, and bioinformatics provided the background for individualizing therapy for systemic autoimmune rheumatic diseases within personalized medicine. Studying the immunopathogenesis mechanisms, improving diagnostics, interpreting the molecular taxonomy, and developing approaches to the prevention and personalized therapy of systemic autoimmune rheumatic diseases are the priority issues of modern medicine.

Predominant ligament-centric soft-tissue involvement differentiates axial psoriatic arthritis from ankylosing spondylitis

Since the original description of spondyloarthritis 50 years ago, results have demonstrated similarities and differences between ankylosing spondylitis (AS) and axial psoriatic arthritis (PsA). HLA-B27 gene carriage in axial inflammation is linked to peri-fibrocartilaginous sacroiliac joint osteitis, as well as to spinal peri-entheseal osteitis, which is often extensive and which provides a crucial anatomical and immunological differentiation between the AS and PsA phenotypes. Specifically, HLA-B27-related diffuse bone marrow oedema (histologically an osteitis) and bone marrow fatty corners detected via magnetic resonance imaging, as well as radiographic changes such as sacroiliitis, vertebral squaring, corner erosions and Romanus lesions, all indicate initial bone phenotypes in HLA-B27+ axial disease. However, in much of PsA with axial involvement, enthesitis primarily manifests in ligamentous soft tissue as 'ligamentitis', with characteristic lesions that include para-syndesmophytes and sacroiliac joint bony sparing. Like axial PsA, diffuse idiopathic skeletal hyperostosis phenotypes, which can be indistinguishable from PsA, exhibit a thoracic and cervical spinal ligamentous soft-tissue tropism, clinically manifesting as syndesmophytosis that is soft-tissue-centric, including paravertebral soft-tissue ossification and sacroiliac soft-ligamentous ossification instead of joint-cavity fusion. The enthesis bone and soft tissues have radically different immune cell and stromal compositions, which probably underpins differential responses to immunomodulatory therapy, especially IL-23 inhibition.

Behçet's Disease: A Comprehensive Review on the Role of HLA-B*51, Antigen Presentation, and Inflammatory Cascade

Behçet's disease (BD) is a complex, recurring inflammatory disorder with autoinflammatory and autoimmune components. This comprehensive review aims to explore BD's pathogenesis, focusing on established genetic factors. Studies reveal that HLA-B*51 is the primary genetic risk factor, but non-HLA genes (ERAP1, IL-10, IL23R/IL-12RB2), as well as innate immunity genes (FUT2, MICA, TLRs), also contribute. Genome-wide studies emphasize the significance of ERAP1 and HLA-I epistasis. These variants influence antigen presentation, enzymatic activity, and HLA-I peptidomes, potentially leading to distinct autoimmune responses. We conducted a systematic review of the literature to identify studies exploring the association between HLA-B*51 and BD and further highlighted the roles of innate and adaptive immunity in BD. Dysregulations in Th1/Th2 and Th17/Th1 ratios, heightened clonal cytotoxic (CD8+) T cells, and reduced T regulatory cells characterize BD's complex immune responses. Various immune cell types (neutrophils, γδ T cells, natural killer cells) further contribute by releasing cytokines (IL-17, IL-8, GM-CSF) that enhance neutrophil activation and mediate interactions between innate and adaptive immunity. In summary, this review advances our understanding of BD pathogenesis while acknowledging the research limitations. Further exploration of genetic interactions, immune dysregulation, and immune cell roles is crucial. Future studies may unveil novel diagnostic and therapeutic strategies, offering improved management for this complex disease.

The Influence of Time on the Epidemiology and Clinical Manifestations of Behçet's Disease in Brazil

OBJECTIVE

Modifications in the severity and clinical expression of Behçet's disease (BD) have been described in some areas that are considered endemic for the disease. This study aims to evaluate the chronological changes in epidemiology and clinical characteristics of BD patients in a referral center in Brazil, which is considered a non-endemic area for the disease.

METHODS

A descriptive and cross-sectional study involving BD patients divided into two groups: group 1 patients were diagnosed and followed between 1988 and 2010, and group 2 were diagnosed and followed between 2011 and 2022.

RESULTS

No significant differences were found regarding gender and age at onset of symptoms between groups. We found a significant decrease in the frequency of bilateral ocular involvement, posterior uveitis, and retinal vasculitis.

CONCLUSION

The demographic dates of this group of Brazilian BD patients remained similar over the last decade. Our study supports the notion that BD is becoming lighter in some regions. BD is a severe blinding disorder, and we found a lower frequency of ocular involvement over time. These findings may be attributed to a higher level of education of patients and a growing awareness of the disease. Newer immunomodulating and biologic agents may offer an improved prognosis in patients with BD with severe manifestations.

When it looks like Behçet's syndrome but is something else: differential diagnosis of Behçet's syndrome: a two-centre retrospective analysis

OBJECTIVE

To investigate the differential diagnostic spectrum in patients with suspected Behçet's syndrome (BS) in low prevalence regions. In addition, the number of patients fulfilling the ICBD criteria despite not having BS was evaluated.

METHODS

This retrospective analysis was performed in two referral centres for BS. Patients with confirmed BS (clinical diagnosis with fulfilment of ISG criteria or a score of ≥5 points in the ICBD criteria) were excluded. The remaining patients were divided into 11 differential diagnosis categories. If no definitive alternative diagnosis could be established, patients were termed 'probable BS' in case of (i) relapsing orogenital aphthosis in the absence of other causes and either HLA-B51 positivity, or origin from an endemic area or presence of an additional typical BS symptom that is not part of the classification criteria, or (ii) with 3-4 points scored in the ICBD criteria.

RESULTS

In total 202 patients were included and categorized as follows: 58 patients (28.7%) as 'probable BS', 57 (28.2%) skin disease, 26 (12.9%) chronic pain syndrome, 14 (6.9%) eye disease, 11 (5.4%) spondyloarthropathy, 9 (4.5%) gastrointestinal disease, 7 (3.5%) neurological disease, 4 (2%) arthritis, 3 (1.5%) auto-inflammation, 3 (1.5%) connective tissue disease and 10 (5.0%) miscellaneous disease. HLA-B51 was positive in 55/132 (41.7%); 75/202 (37.1%) of the patients fulfilled the ICBD criteria.

CONCLUSION

In a low disease prevalence setting, the straightforward application of the ICBD criteria may lead to overdiagnosis of BS. The differential diagnosis of BS is enormously broad. Clinicians should be aware that HLA-B51 positivity is still not considered as a diagnostic feature in BS.

Neurological involvement by Behçet's syndrome: clinical features, diagnosis, treatment and outcome

Neurological involvement in Behçet's syndrome arises predominately through an inflammatory meningoencephalitis characterised by perivenular inflammation due to activation of Th-17 immunological pathways. The brainstem is involved in 50% of cases, the diencephalon and other areas of the brain in 30%, and the spinal cord in 10%. Movement disorders and epilepsy may occur. Psychiatric syndromes may arise with brain and brainstem involvement, and cognitive disorders relate to the brain disease, to circulating inflammatory factors, and to fatigue and despondency. Eighty per cent of cases begin with a relapsing disease course, of whom 70% have only one attack, and 30% have a progressive disease course either from onset or following an initially relapsing course. Venous thrombosis leading to intracranial hypertension and cerebral venous infarction is less common and caused by inflammation in affected veins and a circulating prothrombotic state. Arterial involvement is rare and relates to an arteritis affecting large-sized and medium-sized vessels within the brain leading to infarction, subarachnoid and parenchymal haemorrhage, aneurysm formation and arterial dissection. There is a newly recognised disorder of cerebral cortical hypoperfusion. Cranial neuropathy, peripheral neuropathy and myositis are rare. There has been significant progress in understanding the pathophysiology and treatment of the systemic disease, leading to improved outcomes, but there has been no randomised trial of treatment in the neurological disorder.

Associations between vitamin D and autoimmune diseases: Mendelian randomization analysis

OBJECTIVE

The VITAL trial of vitamin D supplementation suggested a possible protective effect for autoimmune diseases but uncertainties remain. We investigated potential causal effects of vitamin D on composite and individual autoimmune diseases using Mendelian randomization.

METHODS

We used data from 332,984 participants of the UK Biobank of whom 23,089 had at least one autoimmune disease defined using ICD code and/or self-report. Diseases were further considered in mechanistic subgroups driven by "autoimmunity" (n = 12,774) or "autoinflammation" (n = 11,164), then individually. We selected variants within gene regions implicated in vitamin D biology to generate a weighted genetic score. We performed population-wide analysis using the ratio method, then examined non-linear effects across five quantiles based on 25-hydroxycholecalciferol levels.

RESULTS

Genetically-predicted vitamin D was associated with lower risk of diseases in the autoinflammation group (OR 0.95 per 10 ng/ml increase in 25-hydroxycholecalciferol; 95%CI 0.91-0.99; p = 0.03) but not the autoimmunity group (OR 0.99; 95%CI 0.95-1.03; p = 0.64) or combined. When considering individual diseases, genetically-predicted vitamin D was associated with lower risk of psoriasis (OR 0.91; 95%CI 0.85-0.97; p = 0.005), the most common disease in the autoinflammation group, and suggestively with systemic lupus erythematosus (OR 0.84; 95%CI 0.69-1.02; p = 0.08); results were replicated using data from independent studies. We found no evidence for a plausible non-linear relationship between vitamin D and any outcome.

CONCLUSIONS

We found genetic evidence to support a causal link between 25-hydroxycholecalciferol concentrations and psoriasis and systemic lupus erythematosus. These results have implications for potential disease prevention strategies, and the interpretation and design of vitamin D supplementation trials.

Ankylosing spondylitis is associated with increased prevalence of valvular heart diseases: a cross-sectional population-based study

BACKGROUND

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis primarily affecting the sacroiliac joint and axial skeleton with associated extra-articular involvement including cardiovascular system disease including aortic valve disease with variable reported prevalence. The aim of this study is to determine the prevalence of heart valve disorders in AS patients.

METHODS

This was a retrospective, population-based, cross-sectional study that retrieved data from the Clalit Health Services registry. Cases were defined as having AS, whereas controls were frequency matched by age and sex in a ratio of 5:1. The prevalence of valvular heart diseases was compared between the two groups; a multivariate logistic regression model was applied to estimate the association after controlling for potential confounders.

RESULTS

We included 4082 AS patients and 20 397 controls frequency matched by age and sex. AS patients had a significantly higher prevalence of cardiovascular risk factors (P < .001) and a higher prevalence of valvular heart disease. In the multivariate logistic regression model, adjusting for multiple confounding factors, AS was independently associated with aortic stenosis [odds ratio (OR): 2.25, 95% confidence interval (CI): 1.57-3.23, P < 0.001], aortic insufficiency (OR: 2.44, 95% CI: 1.50-3.94, P < 0.001), and mitral insufficiency (OR: 1.75, 95% CI: 1.17-2.61, P < 0.001) but not mitral stenosis (OR: 1.31, 95% CI: 0.60-2.70, P = 0.47).

CONCLUSIONS

Our study reports the increased risk of valvular heart diseases in patients with AS, possibly due to the inflammatory milieu associated with the disease process and the result of biomechanical stress affecting the enthesis-like valvular structures.

Panniculitis with late onset enthesitis-related arthritis: a case report

BACKGROUND

Panniculitis, a type of inflammation of subcutaneous fat, is a relatively uncommon condition that usually presents as inflammatory nodules or plaques, with various proposed etiologic factors. The association between panniculitis and enthesitis-related arthritis has not been described previously.

CASE PRESENTATION

Herein, we describe a case of a 11-year-old girl who presented with recurrent fever and painful subcutaneous nodules on her extremities and buttocks. Histological examination of the skin biopsy specimen revealed lobular panniculitis. Despite the use of prednisone and mycophenolate mofetil for several months, the patient experienced a relapse of skin lesions and additional symptoms of peripheral joint swelling and inflammatory lumbar pain. She was diagnosed with enthesitis-related arthritis after confirmation by imaging. The panniculitis demonstrated a sustained response when a tumor necrosis factor alpha inhibitor was used for enthesitis-related arthritis. At 2-year follow-up, her skin lesions and arthritis remained stable.

CONCLUSIONS

Although rare, panniculitis can be considered an unusual extra-articular manifestation of enthesitis-related arthritis based on clinical and pathological insights.

Peripheral spondyloarthritis: What have we learned?

The peripheral spondyloarthritis (pSpA) entity remains poorly defined in comparison with axial SpA and psoriatic arthritis, as the clinical symptoms have low specificity, the biological markers are virtually lacking, and dedicated randomized controlled trials in this specific indication remain scarce. In addition, clinical similarities between pSpA and psoriatic arthritis (PsA) have been described, partly explained by a resemblance in the pathophysiology of both entities. Thus, diagnosing pSpA can be challenging because of the overlap with other entities and the absence of a specific test or imaging study that can definitively diagnose the condition. The aim of this review is to summarize the current understanding of pSpA, its epidemiology, physiopathology, clinical diagnosis, and classification criteria. In addition, we present patient-reported outcomes used in pSpA clinical studies, available evidence on therapies, and future directions.

Tutorial: a statistical genetics guide to identifying HLA alleles driving complex disease

The human leukocyte antigen (HLA) locus is associated with more complex diseases than any other locus in the human genome. In many diseases, HLA explains more heritability than all other known loci combined. In silico HLA imputation methods enable rapid and accurate estimation of HLA alleles in the millions of individuals that are already genotyped on microarrays. HLA imputation has been used to define causal variation in autoimmune diseases, such as type I diabetes, and in human immunodeficiency virus infection control. However, there are few guidelines on performing HLA imputation, association testing, and fine mapping. Here, we present a comprehensive tutorial to impute HLA alleles from genotype data. We provide detailed guidance on performing standard quality control measures for input genotyping data and describe options to impute HLA alleles and amino acids either locally or using the web-based Michigan Imputation Server, which hosts a multi-ancestry HLA imputation reference panel. We also offer best practice recommendations to conduct association tests to define the alleles, amino acids, and haplotypes that affect human traits. Along with the pipeline, we provide a step-by-step online guide with scripts and available software ( https://github.com/immunogenomics/HLA_analyses_tutorial ). This tutorial will be broadly applicable to large-scale genotyping data and will contribute to defining the role of HLA in human diseases across global populations.

Characteristics of Patients With Behçet Disease From the Van Province, Eastern Turkey: Definition of Disease Clusters in a Tertiary Referral Center

BACKGROUND

Behçet disease (BD) is a chronic inflammatory systemic disease that affects skin mucosa, joints, eyes, and blood vessels. Behçet disease shows some clinical differences in terms of disease manifestations and prognosis among the Silk Road countries, as well as various ethnicities even in the same country. In this study, we aimed to evaluate the clinical features and disease course of BD using cluster analysis in Van province, Eastern Turkey.

METHODS

This study was carried out in a tertiary referral center in Van province, by reviewing medical records. Seven disease manifestations were included to the cluster analysis as follows: mucocutaneous findings (oral ulcer, genital ulcer, erythema nodosum-like lesions, pseudofolliculitis), uveitis, superficial thrombophlebitis, musculoskeletal involvement, gastrointestinal system involvement, vascular involvement, and parenchymal central nervous system involvement.

RESULTS

We identified 467 patients. After the exclusion of 6 patients who had missing data and 17 patients who did not live in Van, 444 patients (59.2% male) included into the study. Meeting the International Study Group and the International Criteria for Behçet Disease criteria were 91.6% and 96%, respectively, and 91.3% (n = 379/415) of these patients met both criteria. Four clusters were identified in the analyses: 132 patients (31.2%) in vascular (C1), 66 patients (15.6%) in ocular (C2), 60 patients (14.2%) in musculoskeletal (C3), and 165 patients (39%) in mucocutaneous (C4) clusters. Male gender ( p = 0.002; odds ratio [OR], 6.5; 95% confidence interval [CI], 2-21.4), superficial thrombophlebitis ( p = 0.001; OR, 4.7; 95% CI, 1.9-11.4), and uveitis ( p = 0.01; OR, 3.6; 95% CI, 1.3-9.9) were associated with vascular involvement in multivariate analysis.

CONCLUSIONS

In our study, 4 clusters were detected in patients with BD from Van province. The prevalence of severe manifestations of BD may be related to genetic or environmental factors, such as differences in ethnicity and/or geographical differences. Despite the higher proportion of patients with a more severe disease, a favorable outcome was observed in our cohort.

Clinical trait-specific genetic analysis in Behçet's disease identifies novel loci associated with ocular and neurological involvement

Behçet's disease is a complex inflammatory vasculitis with a broad spectrum of clinical manifestations. The purpose of this study was to investigate the genetics underlying specific clinical features of Behçet's disease. A total of 436 patients with Behçet's disease from Turkey were studied. Genotyping was performed using the Infinium ImmunoArray-24 BeadChip. After imputation and quality control measures, logistic regressions adjusting for sex and the first five principal components were performed for each clinical trait using a case-case genetic analysis approach. A weighted genetic risk score was calculated for each clinical feature. Genetic association analyses of previously identified susceptibility loci in Behçet's disease revealed a genetic association between ocular lesions and HLA-B/MICA (rs116799036: OR = 1.85 [95% CI = 1.35-2.52], p-value = 1.1 × 10-4). The genetic risk score was significantly higher in Behçet's disease patients with ocular lesions compared to those without ocular involvement, which is explained by the genetic variation in the HLA region. New genetic loci predisposing to specific clinical features in Behçet's disease were suggested when genome-wide variants were evaluated. The most significant associations were observed in ocular involvement with SLCO4A1 (rs6062789: OR = 0.41 [95% CI = 0.30-0.58], p-value = 1.92 × 10-7), and neurological involvement with DDX60L (rs62334264: OR = 4.12 [95% CI 2.34 to 7.24], p-value = 8.85 × 10-7). Our results emphasize the role of genetic factors in predisposing to specific clinical manifestations in Behçet's disease, and might shed additional light into disease heterogeneity, pathogenesis, and variability of Behçet's disease presentation across populations.

Distinct modulation of cellular immunopeptidome by the allosteric regulatory site of ER aminopeptidase 1

ER aminopeptidase 1 (ERAP1) is an ER-resident aminopeptidase that excises N-terminal residues of peptides that then bind onto Major Histocompatibility Complex I molecules (MHC-I) and indirectly modulates adaptive immune responses. ERAP1 contains an allosteric regulatory site that accommodates the C-terminus of at least some peptide substrates, raising questions about its exact influence on antigen presentation and the potential of allosteric inhibition for cancer immunotherapy. We used an inhibitor that targets this regulatory site to study its effect on the immunopeptidome of a human cancer cell line. The immunopeptidomes of allosterically inhibited and ERAP1 KO cells contain high-affinity peptides with sequence motifs consistent with the cellular HLA class I haplotypes but are strikingly different in peptide composition. Compared to KO cells, allosteric inhibition did not affect the length distribution of peptides and skewed the peptide repertoire both in terms of sequence motifs and HLA allele utilization, indicating significant mechanistic differences between the two ways of disrupting ERAP1 function. These findings suggest that the regulatory site of ERAP1 plays distinct roles in antigenic peptide selection, which should be taken into consideration when designing therapeutic interventions targeting the cancer immunopeptidome.

Role of tumor necrosis factor-alpha in the central nervous system: a focus on autoimmune disorders

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic immune cytokine that belongs to the TNF superfamily of receptor ligands. The cytokine exists as either a transmembrane or a soluble molecule, and targets two distinct receptors, TNF-α receptor 1 (TNFR1) and TNF-α receptor 2 (TNFR2), which activate different signaling cascades and downstream genes. TNF-α cellular responses depend on its molecular form, targeted receptor, and concentration levels. TNF-α plays a multifaceted role in normal physiology that is highly relevant to human health and disease. In the central nervous system (CNS), this cytokine regulates homeostatic functions, such as neurogenesis, myelination, blood-brain barrier permeability and synaptic plasticity. However, it can also potentiate neuronal excitotoxicity and CNS inflammation. The pleiotropism of TNF-α and its various roles in the CNS, whether homeostatic or deleterious, only emphasizes the functional complexity of this cytokine. Anti-TNF-α therapy has demonstrated effectiveness in treating various autoimmune inflammatory diseases and has emerged as a significant treatment option for CNS autoimmune diseases. Nevertheless, it is crucial to recognize that the effects of this therapeutic target are diverse and complex. Contrary to initial expectations, anti-TNF-α therapy has been found to have detrimental effects in multiple sclerosis. This article focuses on describing the various roles, both physiological and pathological, of TNF-α in the CNS. Additionally, it discusses the specific disease processes that are dependent or regulated by TNF-α and the rationale of its use as a therapeutic target.

Oral Lesions as the Primary Manifestations of Behçet's Disease: The Importance of Interdisciplinary Diagnostics-A Case Report

BACKGROUND

Behçet's disease (BD) is a rare chronic auto-inflammatory systemic disease with non-specific oral manifestations, categorised as generalised variable vessel vasculitis that requires an interdisciplinary approach to diagnose due to its phenotypic heterogeneity. Whilst the oral lesions that reoccur in BD underpin the complex diagnostic process, the crucial role of dental professionals is highlighted in a case report summarised herein. We present a case of a 47-year-old male referred to the Oral Medicine Department by a rheumatologist after previous hospitalization for thrombosis of the iliac vein and inferior vena cava. He had elevated inflammatory C-reactive protein biomarker and an increased erythrocyte sedimentation rate. Recurrent episodes of folliculitis, oral and genital ulcers were reported. Clinical examination revealed multiple ulcerations in the oral mucosa. The complementary, histopathological analysis performed to rule out other disorders, based on excisional biopsy, showed non-keratinised stratified squamous epithelium with areas of exocytosis and ulceration. The connective tissue presented an intense mixed inflammatory infiltrate, congested blood vessels, haemorrhage, vasculitis, and HLA-B genotyping identified the expression of HLA-B15, further supporting the BD diagnosis. Treatment was initiated with colchicine, prednisolone, and weekly subcutaneous administration of methotrexate and resulted in the complete remission of oral lesions and no recurrence of other manifestations.

CONCLUSIONS

This BD case report emphasizes the importance of a multidisciplinary approach in diagnosing BD, including the use of histopathological assessment and genetic profiling. It highlights the significance of thorough intraoral assessment and referral to a multidisciplinary team for diagnosis. The oral manifestations of BD as the primary symptoms often indicate underlying major systemic pathologies. The authors stress the need for a structured diagnostic algorithm to facilitate timely and effective management of BD.

Musculoskeletal manifestations in children with Behçet's syndrome: data from the AIDA Network Behçet's Syndrome Registry

This study aims to describe musculoskeletal manifestations (MSM) in children with Behçet's syndrome (BS), their association with other disease manifestations, response to therapy, and long-term prognosis. Data were retrieved from the AIDA Network Behçet's Syndrome Registry. Out of a total of 141 patients with juvenile BS, 37 had MSM at disease onset (26.2%). The median age at onset was 10.0 years (IQR 7.7). The median follow-up duration was 21.8 years (IQR 23.3). Recurrent oral (100%) and genital ulcers (67.6%) and pseudofolliculitis (56.8%) were the most common symptoms associated with MSM. At disease onset, 31 subjects had arthritis (83.8%), 33 arthralgia (89.2%), and 14 myalgia (37.8%). Arthritis was monoarticular in 9/31 cases (29%), oligoarticular in 10 (32.3%), polyarticular in 5 (16.1%), axial in 7 (22.6%). Over time, arthritis became chronic-recurrent in 67.7% of cases and 7/31 patients had joint erosions (22.6%). The median Behçet's Syndrome Overall Damage Index was 0 (range 0-4). Colchicine was inefficacious for MSM in 4/14 cases (28.6%), independently from the type of MSM (p = 0.46) or the concomitant therapy (p = 0.30 for cDMARDs, p = 1.00 for glucocorticoids); cDMARDs and bDMARDs were inefficacious for MSM in 6/19 (31.4%) and 5/12 (41.7%) cases. The presence of myalgia was associated with bDMARDs inefficacy (p = 0.014). To conclude, MSM in children with BS are frequently associated with recurrent ulcers and pseudofolliculitis. Arthritis is mostly mono- or oligoarticular, but sacroiliitis is not unusual. Prognosis of this subset of BS is overall favorable, though the presence of myalgia negatively affects response to biologic therapies. ClinicalTrials.gov Identifier: NCT05200715 (registered on December 18, 2021).

EULAR study group on ‘MHC-I-opathy’: identifying disease-overarching mechanisms across disciplines and borders

The ‘MHC-I (major histocompatibility complex class I)-opathy’ concept describes a family of inflammatory conditions with overlapping clinical manifestations and a strong genetic link to the MHC-I antigen presentation pathway. Classical MHC-I-opathies such as spondyloarthritis, Behçet’s disease, psoriasis and birdshot uveitis are widely recognised for their strong association with certain MHC-I alleles and gene variants of the antigen processing aminopeptidases ERAP1 and ERAP2 that implicates altered MHC-I peptide presentation to CD8+T cells in the pathogenesis. Progress in understanding the cause and treatment of these disorders is hampered by patient phenotypic heterogeneity and lack of systematic investigation of the MHC-I pathway.

Here, we discuss new insights into the biology of MHC-I-opathies that strongly advocate for disease-overarching and integrated molecular and clinical investigation to decipher underlying disease mechanisms. Because this requires transformative multidisciplinary collaboration, we introduce the EULAR study group on MHC-I-opathies to unite clinical expertise in rheumatology, dermatology and ophthalmology, with fundamental and translational researchers from multiple disciplines such as immunology, genomics and proteomics, alongside patient partners. We prioritise standardisation of disease phenotypes and scientific nomenclature and propose interdisciplinary genetic and translational studies to exploit emerging therapeutic strategies to understand MHC-I-mediated disease mechanisms. These collaborative efforts are required to address outstanding questions in the etiopathogenesis of MHC-I-opathies towards improving patient treatment and prognostication.

Association between psoriatic disease and lifestyle factors and comorbidities: cross-sectional analysis and Mendelian randomization

OBJECTIVES

To examine associations between PsA and psoriasis vs lifestyle factors and comorbidities by triangulating observational and genetic evidence.

METHODS

We analysed cross-sectional data from the UK Biobank (1836 PsA, 8995 psoriasis, 36 000 controls) to describe the association between psoriatic disease and lifestyle factors (including BMI and smoking) and 15 comorbidities [including diabetes and coronary artery disease (CAD)] using logistic models adjusted for age, sex and lifestyle factors. We applied bidirectional Mendelian randomization (MR) to genome-wide association data (3609 PsA and 7804 psoriasis cases, up to 1.2 million individuals for lifestyle factors and 757 601 for comorbidities) to examine causal direction, using the inverse-variance weighted method.

RESULTS

BMI was cross-sectionally associated with risk of PsA (OR 1.31 per 5 kg/m2 increase; 95% CI 1.26, 1.37) and psoriasis (OR 1.23; 1.20, 1.26), with consistent MR estimates (PsA OR 1.38; 1.14, 1.67; psoriasis OR 1.36; 1.18, 1.58). In both designs, smoking was more strongly associated with psoriasis than PsA. PsA and psoriasis were cross-sectionally associated with diabetes (OR 1.35 and 1.39, respectively) and CAD (OR 1.56 and 1.38, respective). Genetically predicted glycated haemoglobin (surrogate for diabetes) increased PsA risk (OR 1.18 per 6.7 mmol/mol increase; 1.02, 1.36) but not psoriasis. Genetic liability to PsA (OR 1.05; 1.003, 1.09) and psoriasis (OR 1.03; 1.001, 1.06) were associated with increased risk of CAD.

CONCLUSION

Observational and genetic evidence converge to suggest that BMI and glycaemic control are associated with increased psoriatic disease risk, while psoriatic disease is associated with increased CAD risk. Further research is needed to understand the mechanism of these associations.

From Bench to Bedside in Rheumatoid Arthritis from the "2022 GISEA International Symposium"

While precision medicine is still a challenge in rheumatic disease, in recent years many advances have been made regarding pathogenesis, the treatment of inflammatory arthropathies, and their interaction. New insight into the role of inflammasome and synovial tissue macrophage subsets as predictors of drug response give hope for future tailored therapeutic strategies and a personalized medicine approach in inflammatory arthropathies. Here, we discuss the main pathogenetic mechanisms and therapeutic approaches towards precision medicine in rheumatoid arthritis from the 2022 International GISEA/OEG Symposium.

Role of neutrophil interleukin-23 in spondyloarthropathy spectrum disorders

Neutrophilic inflammation is a pervasive characteristic common to spondyloarthropathies and related disorders. This inflammation manifests as Munro's microabscesses of the skin and osteoarticular neutrophilic inflammation in patients with psoriatic arthritis, intestinal crypt abscesses in patients with inflammatory bowel disease, ocular hypopyon in anterior uveitis, and neutrophilic macroscopic and microscopic inflammation in patients with Behçet's disease. Strong MHC class I associations are seen in these diseases, which represent so-called MHC-I-opathies, and these associations indicate an involvement of CD8 T-cell immunopathology that is not yet well understood. In this Personal View, we highlight emerging data suggesting that the T-cell-neutrophil axis involves both a T-cell-mediated and interleukin (IL)-17-mediated (type 17) recruitment and activation of neutrophils, and also a sequestration of activated neutrophils at disease sites that might directly amplify type 17 T-cell responses. This amplification likely involves neutrophilic production of IL-23 and proteases as well as other feedback mechanisms that could be regulated by local microbiota, pathogens, or tissue damage. This crosstalk between innate and adaptive immunity offers a novel explanation for how bacterial and fungal microbes at barrier sites could innately control type 17 T-cell development, with the aim of restoring tissue homoeostasis, and could potentially explain features of clinical disease and treatment response, such as the fast-onset action of the IL-23 pathway blockade in certain patients. This axis could be crucial to understanding non-response to IL-23 inhibitors among patients with ankylosing spondylitis, as the axial skeleton is a site rich in neutrophils and a site of haematopoiesis with myelopoiesis in adults.

Lesion probability map in cerebral vein thrombosis due to Behçet's disease

AIM

Behçet's disease (BD) is a multisystemic inflammatory disease. Cerebral venous sinus thrombosis (CVST) is the second most common form of neuro-BD after parenchymal central nervous system involvement. The purpose of this study was to construct flow-void probability maps of patients with CVST with and without BD to visually illustrate the impacted cerebral venous sinuses, to compare the subgroups of patients, and investigate the effect of thrombus localization on clinical findings.

METHODS

Seventeen patients with a diagnosis of BD-related CVST (CVST-BD) and 23 patients with a diagnosis of CVST related to other etiologies (CVST-O) were included. We collected data including gender, age at onset of BD and CVST, presenting symptoms, neurological findings, and the etiology. High-resolution magnetic resonance venographies obtained during CVST were used to mark and digitalize thrombosed areas. Thrombus probability and subtraction maps were created to reveal the differences between the subgroups.

RESULTS

Remarkably, all patients with CVST-BD had thrombosis in the transverse sinus (TS). However, TS was affected in 73.9% of the CVST-O patients (17/17 in CVST-BD vs 17/23 in CVST-O, P = .03). Thrombosis developed mostly in the superior sagittal sinus (SSS) and TS in the CVST-O group (11/23, 47.8% and 17/23, 73.9%, respectively). The frequency of SSS thrombosis tended to be higher in the CVST-O (47.8% vs 23.5%, P = .19).

CONCLUSION

Venous infarction and hemorrhage were less common in patients with CVST-BD. The only clinical symptom in most of the CSVT patients with BD was headache due to elevated intracranial pressure. TS thrombosis was more common in patients with BD.

The diagnostic role of pathergy test in patients with Behçet's disease from the Western Europe

The aim of the study is to evaluate the frequency and features of positive pathergy test (PPT) in Italy, its role in the diagnosis of Behçet's disease (BD), and any association with other BD-related manifestations. 52 BD patients, 52 patients with axial spondyloarthritis (ax-SpA), and 26 healthy controls (HCs) underwent intradermal injection of normal saline and intradermal needle soaked with fresh self-saliva. The results of pathergy tests were statistically analysed in the light of demographic, clinical, and therapeutic features of subjects enrolled. Pathergy test performed with saline resulted always negative in all groups. Skin prick test using self-saliva resulted in the occurrence of a papule in 3 (5.8%) BD patients and in 1 (1.9%) patient with ax-SpA. A ≥ 15 mm erythematous area surrounding the needle prick site was observed in 22 (42.3%) BD patients, 5 (9.6%) patients with ax-SpA, and 2 (7.7%) HCs (p = 0.00002). The frequency of skin erythema was significantly more frequent in patients with BD than those with ax-SpA (p < 0.0001) and HCs (p = 0.003). No statistically significant differences were observed between ax-SpA patients and HCs (p = 1.000). The occurrence of skin erythema at pathergy test was not associated with any BD-related clinical manifestation. Erythema at self-saliva prick test presented a sensitivity of 42.31% (CI 28.73-56.80%) and a specificity of 91.03% (CI 82.38-96.32%). The development of a ≥ 15 mm erythematous area at self-saliva prick test could be sufficient to unveil the hyper-reactivity of the innate immune system in BD patients from Western Europe, where the development of skin erythema shows good sensitivity and specificity toward the diagnosis of BD.