HLA-B51/B5 and the risk of Behçet's disease: a systematic review and meta-analysis of case-control genetic association studies

Approaches based on miRNAs in Behçet's Disease: Unveiling pathogenic mechanisms, diagnostic strategies, and therapeutic applications

Behçet's Disease (BD) is an intricate medical puzzle, captivating researchers with its enigmatic pathogenesis. This complex ailment, distinguished by recurrent mouth and genital lesions, eye irritation, and skin injuries, presents a substantial obstacle to therapeutic research. This review explores the complex interaction of microRNAs (miRNAs) with BD, highlighting their crucial involvement in the disease's pathophysiology. miRNAs, recognized for regulatory influence in diverse biological processes, hold a pivotal position in the molecular mechanisms of autoimmune diseases, such as BD. The exploration begins with examining miRNA biogenic pathways and functions, establishing a foundational understanding of their regulatory mechanisms. Shifting to the molecular landscape governing BD, the review highlights miRNA-mediated impacts on critical signaling pathways like Notch, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and protein kinase B (AKT)/mammalian target of rapamycin (mTOR), offering insights into intricate pathophysiological mechanisms. Dissecting the immunological landscape reveals the profound influence of miRNAs on BD, shedding light on the intricate modulation of immune responses and offering novel perspectives on disease etiology and progression. Beyond molecular intricacies, the review explores the clinical relevance of miRNAs in BD, emphasizing their potential as diagnostic and prognostic indicators. The discussion extends to the promising realm of miRNA-based therapeutic interventions, highlighting their potential in alleviating symptoms and altering disease progression. This comprehensive review, serving as a valuable resource for researchers, clinicians, and stakeholders, aims to decipher the intricate molecular tapestry of BD and explore the therapeutic potential of miRNAs.

Cardiovascular Manifestations in Behçet's Disease

Cardiovascular involvement in Behçet's disease (BD) is considerably related to morbidity and mortality. However, the cardiovascular manifestation is sometimes difficult to distinguish from those of other causes. The suspicion of BD and proper treatment is pivotal in the management of BD. Histology demonstrates perivasculitis. Neutrophil seems to play an important role in the inflammation of BD. It is thought that inflammation causes venous thrombosis and arterial aneurysm. Characteristically, BD involves both arteries and veins of variable size in any region. Venous thrombosis needs immunosuppression, and inferior vena cava thrombosis and Budd-Chiari syndrome require intensive immunosuppressive therapy. Arterial involvement causes aneurysm which usually is treated by surgical or endovascular intervention with immunosuppression. Pulmonary artery aneurysm and cardiac involvement require multimodal managements.

Carnosic Acid: A Novel Selective Inhibitor of ERAP1 by Direct Binding and Its Modulation of Antigen Processing and Presentation

ERAP1 is an emerging target for a large subclass of severe autoimmune diseases known as "MHC-I-opathy", together with tumor immunity. Nevertheless, effective inhibitors targeting ERAP1 remain a challenge. In this study, a novel food-derived natural product ERAP1-targeting inhibitor, carnosic acid, was identified, and to our knowledge, it is one of the best active compounds among the highly selective inhibitors targeting the orthosteric site of ERAP1. The results reveal that carnosic acid could bind strongly, like a key to the ERAP1 active site in the biased S1' pocket, which is different from the binding mode of the existing orthosteric site inhibitors. HLA-B27-mediated cell modeling validated that carnosic acid has the activity to reverse the AS-associated cellular phenotype brought on by ERAP1 through inhibition. Our findings provide insights into the design of potent inhibitors against the ERAP1 orthosteric site and the discovery of a key direct target of carnosic acid.

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.

Fever, Leukocytosis, and Ulcerated Vulvar Lesions: An Atypical Presentation Concerning Behcet's Disease

Behcet's disease (BD) is a variable-vessel vasculitis commonly presenting in early adulthood with painful oral aphthous ulcers, genital ulcers, uveitis, pathergy, and skin lesions. The diagnosis of BD is made clinically based on criteria from the International Study Group (ISG) and the International Criteria for Behcet's Disease (ICBD). Due to the wide constellation of symptoms BD can cause, it can be challenging to diagnose in an acute setting. Here, we discuss a patient who presented with a clinical picture of sepsis, with profound ulcerated vulvar and herpetiform oral mucosal lesions, that led us to a presumptive diagnosis of Behcet's disease.

Blue Toe Syndrome in Behçet's Disease: A Case Report

BACKGROUND Vascular Behçet's disease (VBD) is a rare but potentially life-threatening subtype of Behçet's disease that is characterized by multisystemic vasculitis. It primarily affects males with ancestry traced back to regions along the ancient Silk Road. Both arteries and veins, regardless of size, may exhibit complications, including aneurysmal degeneration or occlusion. While venous involvement is observed in two-thirds of VBD cases, arterial complications are notably the most severe and lethal. Arterial aneurysmal degeneration is more common than occlusive complications, with larger arteries being predominantly affected in VBD. Data regarding isolated small-vessel arterial occlusive disease in VBD are limited. Given the rarity of this presentation in this patient population, it becomes mandatory to thoroughly evaluate such patients to differentiate small-vessel vasculitis from other similar diseases, such as Raynaud's phenomenon, which has a different etiology and management and generally has a more benign course. Here, we delineate the concept of isolated small-vessel vasculitis as a cause of blue toe syndrome in patients with VBD. CASE REPORT This report describes a distinctive case of vascular Behçet's disease in a 51-year-old man who initially exhibited unilateral blue toe syndrome, which swiftly progressed to dry gangrene of the toes. Despite reports of large-vessel involvement, there is a paucity of data on isolated small-vessel vasculitis-induced digital ischemia in VBD. CONCLUSIONS This atypical case underscores the necessity of clinical discernment in differentiating inflammatory microvascular occlusive disease from vasospastic Raynaud's syndrome, both of which can complicate Behçet's disease.

Unique presentation of acute neuro-Behçet's disease involving a cytotoxic edema core surrounded by vasogenic edema

A 53-year-old woman with recurrent stomatitis, genital ulcers, and folliculitis was admitted to our hospital after experiencing visual disturbances for the past two weeks, and a non-throbbing headache for the past three days. She had also developed numbness in her left extremities. An ophthalmological examination revealed inflammatory changes in the eye. Cerebrospinal fluid analysis showed increased cell counts, protein, and interleukin-6 levels. Brain magnetic resonance imaging revealed multiple high signal intensities on T2-weighted (T2W)/fluid-attenuated inversion recovery (FLAIR) images of the pons and occipital and parietal lobes. The T2W/FLAIR high-signal-intensity lesion in the pons was hyperintense on diffusion-weighted imaging (DWI) and hypointense on apparent diffusion coefficient mapping (ADC), suggesting cytotoxic edema. Another high-signal-intensity lesion on T2W/FLAIR was isointense to hyperintense on DWI and hyperintense on ADC, indicating vasogenic edema. The vasogenic edema in the left occipital lobe contained a small core that was hyperintense on DWI and hypointense on ADC, suggesting cytotoxic edema. The patient was diagnosed with acute neuro-Behçet's disease (neuro-BD) and responded well to high-dose glucocorticoid and colchicine treatment. The present report emphasizes that patients with acute neuro-BD may present with cytotoxic edema in the pons and cerebral spheres. Further reports of similar cases would contribute to a better understanding of the role of cytotoxic edema in the pathophysiology of neuro-BD and help elucidate the mechanisms underlying a unique presentation characterized by a central cytotoxic edema core within vasogenic edema. (233 words).

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.

Decoding Behcet's Uveitis: an In-depth review of pathogenesis and therapeutic advances

Behcet's disease (BD) is a rare but globally distributed vasculitis that primarily affects populations in the Mediterranean and Asian regions. Behcet's uveitis (BU) is a common manifestation of BD, occurring in over two-thirds of the patients. BU is characterized by bilateral, chronic, recurrent, non-granulomatous uveitis in association with complications such as retinal ischemia and atrophy, optic atrophy, macular ischemia, macular edema, and further neovascular complications (vitreous hemorrhage, neovascular glaucoma). Although the etiology and pathogenesis of BU remain unclear, numerous studies reveal that genetic factors (such as HLA-B51), dysregulated immune responses of both the innate and adaptive immune systems, infections (such as streptococcus), and environmental factors (such as GDP) are all involved in its development. Innate immunity, including hyperactivity of neutrophils and γδT cells and elevated NK1/NK2 ratios, has been shown to play an essential role in this disease. Adaptive immune system disturbance, including homeostatic perturbations, Th1, Th17 overaction, and Treg cell dysfunction, is thought to be involved in BU pathogenesis. Treatment of BU requires a tailored approach based on the location, severity of inflammation, and systemic manifestations. The therapy aims to achieve rapid inflammation suppression, preservation of vision, and prevention of recurrence. Systemic corticosteroids combined with other immunosuppressive agents have been widely used to treat BU, and beneficial effects are observed in most patients. Recently, biologics have been shown to be effective in treating refractory BU cases. Novel therapeutic targets for treating BU include the LCK gene, Th17/Treg balance, JAK pathway inhibition, and cytokines such as IL-17 and RORγt. This article summarizes the recent studies on BU, especially in terms of pathogenesis, diagnostic criteria and classification, auxiliary examination, and treatment options. A better understanding of the significance of microbiome composition, genetic basis, and persistent immune mechanisms, as well as advancements in identifying new biomarkers and implementing objective quantitative detection of BU, may greatly contribute to improving the adequate management of BU patients.

A Changed Man: A Rare Case of Behcet's Disease Autoimmune Encephalitis

Behcet's disease (BD) is characterized by recurrent oral ulcers with concomitant systemic multi-organ involvement, which may include neurological disease, ocular disease, vascular disease, genital ulcers, skin lesions, and arthritis. The clinical symptoms arise from vasculitis that involves small, medium, and large blood vessels. We present the case of a young male who presented with atypical Behcet's autoimmune encephalitis with recurrent oral ulcers, neurological manifestations, HLA-B51 positivity, abnormal EEG findings, and improvement following multiple plasma exchange treatments.

Replication Study of the Association of GAS6 and PROS1 Polymorphisms with Behçet's Disease in a Japanese Population

PURPOSE

To investigate whether polymorphisms of GAS6 and PROS1, which each encode protein ligands for a family of tyrosine kinase receptors, are associated with Behçet's disease (BD) in a Japanese population.

METHODS

We recruited 734 Japanese patients with BD and 1789 Japanese healthy controls. In all participants, we genotyped two single-nucleotide polymorphisms (SNPs) reportedly associated with BD: rs9577873 in GAS6 and rs4857037 in PROS1.

RESULTS

We found that GAS6 rs9577873 was not significantly associated with BD. In contrast, PROS1 rs4857037, specifically the A allele, was associated with increased risk for BD. The A allele was also significantly associated with BD under additive and recessive genetic models. Expression analysis revealed that this allele was significantly associated with increased PROS1 expression.

CONCLUSIONS

Our findings suggest that increased PROS1 expression related to the A risk allele of rs4857037 affects tyrosine kinase receptor signaling, contributing to the development of BD.

Biology of HLA class I associated inflammatory diseases

Human leukocyte antigen (HLA) class I association is a well-established feature of common and uncommon inflammatory diseases, but it is unknown whether it impacts the pathogenesis of these disorders. The "arthritogenic peptide" hypothesis proposed initially for HLA-B27-associated ankylosing spondylitis (AS) seems the most intuitive to serve as a model for other HLA class I-associated diseases, but evidence supporting it has been scarce. Recent technological advances and the discovery of epistatic relationships between disease-associated HLA class I and endoplasmic reticulum aminopeptidase (ERAP) coding variants have led to the generation of new data and conceptual approaches to the problem requiring its re-examination. Continued success in these endeavors holds promise to resolve a Gordian Knot in human immunobiology. It may ultimately benefit patients by enabling the development of new therapies and precision tools for assessing disease risk and predicting treatment responses.

Prevalence, types, and characteristics of headache in Behcets disease without involvement of the central nervous system in the Syrian population: a case-cohort study

Introduction

Oral ulcers, genital ulcers, and uveitis represent the typical trial of Behcet's disease (BD). It is well common on the Old Silk Road. The mucocutaneous lesions are the hallmark of BD, but neurological involvement is one of the severe symptoms. Headaches may be an early sign of BD neurological involvement. This study aims to investigate the headache prevalence and its types, and characteristics in a Syrian sample of BD patients.

Methods

BD patients were clinically interviewed and examined to collect their information, symptoms, and signs. the International Study Group for Behcet's Disease diagnosis criteria was used to confirm the BD diagnosis. The International Classification of headaches was used when classifying the headaches.

Results

One hundred twenty participants were included in the study. half of them were BD patients and the control group was also 60 participants. Among Syrian BD patients, 36.7% suffer from primary headaches and 36.7% suffer from secondary headaches. These findings were not significantly different between the BD patients and the healthy population. Our results showed that there was no statistically significant difference between the two groups.

Conclusion

Headache should not be considered a predictor for neurological involvement among BD patients. Additional attention to BD patients or the specific treatment for headaches is not required and does not differ from the general population.

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.

Characterization and Management of Amicrobial Pustulosis of the Folds, Aseptic Abscess Syndrome, Behçet Disease, Neutrophilic Eccrine Hidradenitis, and Pyostomatitis Vegetans-Pyodermatitis Vegetans

Neutrophilic dermatoses are a broadly heterogeneous group of inflammatory skin disorders. This article reviews 5 conditions: amicrobial pustulosis of the folds, aseptic abscess syndrome, Behçet disease, neutrophilic eccrine hidradenitis, and pyostomatitis vegetans-pyodermatitis vegetans.The authors include up-to-date information about their epidemiology, pathogenesis, clinicopathologic features, diagnosis, and management.

"Deficiency in ELF4, X-Linked": a Monogenic Disease Entity Resembling Behçet's Syndrome and Inflammatory Bowel Disease

Defining monogenic drivers of autoinflammatory syndromes elucidates mechanisms of disease in patients with these inborn errors of immunity and can facilitate targeted therapeutic interventions. Here, we describe a cohort of patients with a Behçet's- and inflammatory bowel disease (IBD)-like disorder termed "deficiency in ELF4, X-linked" (DEX) affecting males with loss-of-function variants in the ELF4 transcription factor gene located on the X chromosome. An international cohort of fourteen DEX patients was assessed to identify unifying clinical manifestations and diagnostic criteria as well as collate findings informing therapeutic responses. DEX patients exhibit a heterogeneous clinical phenotype including weight loss, oral and gastrointestinal aphthous ulcers, fevers, skin inflammation, gastrointestinal symptoms, arthritis, arthralgia, and myalgia, with findings of increased inflammatory markers, anemia, neutrophilic leukocytosis, thrombocytosis, intermittently low natural killer and class-switched memory B cells, and increased inflammatory cytokines in the serum. Patients have been predominantly treated with anti-inflammatory agents, with the majority of DEX patients treated with biologics targeting TNFα.

Diagnosis and Management of Non-Infectious Uveitis in Pediatric Patients

Uveitis in children accounts for 5-10% of all cases. The causes vary considerably. Classically, uveitis is distinguished according to its infectious or inflammatory origin and whether it is part of a systemic disease or represents an isolated ocular disease. It is important to highlight the specificity of certain etiologies among children such as juvenile idiopathic arthritis. The development of visual function can potentially be hindered by amblyopia (children aged < 7 years), in addition to the usual complications (synechiae, macular edema) seen in adult patients. Moreover, the presentation of uveitis in children is often "silent" with few warning signs and few functional complaints from young children, which frequently leads to a substantial diagnostic delay. The diagnostic approach is guided by the presentation of the uveitis, which can be characterized by its location, and corresponds to the initial and main site of intraocular inflammation; its presentation, whether acute or chronic, granulomatous or not; and the response to treatment. Pediatricians have an important role to play and must be aware of the various presentations and etiologies of uveitis in children. Juvenile idiopathic arthritis is the most common etiology of pediatric non-infectious uveitis, but other causes must be recognized. Promptly initiated treatment before complications arise requires early diagnosis, recognition, and treatment. Any dependence on prolonged local corticosteroid therapy justifies discussing the introduction of a corticosteroid-sparing treatment considering the risk to develop corticoid-induced glaucoma and cataracts. Systemic corticosteroid therapy can be required for urgent control of inflammation in the case of severe uveitis. Long-lasting immunosuppressive treatment and biotherapies are most often prescribed at the same time to reinforce treatment efficacy and to prevent relapse and corticosteroid dependency. We review the different causes of uveitis, excluding infection, and the diagnostic and therapeutic management aimed at limiting the risk of irreversible sequelae.

Case report: Deep vein thrombosis as the sole clinical feature of Behcet's syndrome

Introduction

Behcet's syndrome is a rare, chronic, systemic condition often categorized within the group of vasculitides. It presents a diagnostic challenge due to its varied clinical manifestations and the absence of a definitive laboratory test. Its etiology remains unclear but may involve genetic, infectious, and environmental factors.

Case presentation

We report the case of a 16-year-old male who presented with deep vein thrombosis, followed by recurrent episodes of breakthrough thrombosis, despite adequate anticoagulant therapy. The patient did not meet the International Study Group (ISG) criteria nor the International Criteria for Behcet's syndrome (ICBD) due to the absence of characteristic features such as oral aphthous ulcers, genital ulcers, and uveitis. Later in the disease course, after ruling out other causes of breakthrough thrombosis, he tested positive for HLA-B51, an allele associated with Behcet's syndrome, and exhibited a pathergy reaction.

Discussion

The patient's clinical course underlines the diagnostic complexity associated with Behcet's syndrome and highlights the importance of maintaining a broad differential diagnosis in cases of recurrent thrombosis. Although HLA-B51 testing is not routinely recommended, it played a pivotal role in our case, underscoring the value of an integrated diagnostic approach. Furthermore, this case reinforces the potential for atypical presentations of Behcet's syndrome, necessitating vigilant clinical awareness. After establishing the diagnosis, we successfully treated the patient with immunosuppressive therapy, significantly improving his condition.

Behçet's syndrome: recent advances to aid diagnosis

Behçet's syndrome is a recurring inflammatory multiorgan disorder affecting the skin, mucosa, eyes, joints, stomach, and central nervous system. Behçet's syndrome epidemiology varies greatly among populations (0.64-420/100,000), and Behçet's syndrome has gained increasing international acclaim in the recent 50 years due to raising awareness of the syndrome, although it is rare in most population. In addition to the unclear etiology of the syndrome, the diagnosis of Behçet's syndrome is complicated by a vague clinical presentation, phenotypic heterogeneity and/or incomplete representation, and the lack of any specific laboratory, radiographic, or histological findings. There exists a dire need to elucidate factors that contribute to disease pathogenesis and/or are associated with clinical features of Behçet's syndrome and the classification of different forms of the syndrome. The identification of such molecular, cellular, and/or clinical factors are crucial for timely diagnosis and efficacious management of Behçet's syndrome. We discuss recent advances in the clinical diagnosis of Behçet's syndrome and related contributions of genetics, epigenetics, microbiome, inflammasomes, and autoantibodies to the improved diagnosis, management, and understanding of Behçet's syndrome.

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.

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.

The relationship between HLA-B*51 subtypes, clinical manifestations and severity of Behçet's syndrome: a large Italian cohort study

Objectives

Behçet's syndrome (BS) is a chronic multisystemic inflammatory disorder of unclear aetiology. The predominant BS susceptibility locus was identified within HLA-B*51. HLA-B*51 subtypes were previously studied as disease susceptibility markers. Few data are now available about the relationship between B*51 subtypes and clinical phenotype. The aim of this study was to genotype HLA-B*51 subtypes in a series of Italian BS patients and to test the association with clinical manifestations and disease severity (Krause's index).

Methods

HLA-B*51 subtype genotyping for 63 alleles (B*51:01-B*51:63) was performed by PCR after DNA extraction from whole blood of BS patients. The correlation of disease clinical manifestations and severity (Krause's index) with the HLA-B*51 allele and its subtypes was analysed.

Results

We enrolled 241 (140 male and 101 female) BS patients, and HLA-B*51 frequency was 62.7% (151 of 241). One hundred and eight of the HLA-B*51-positive patients carried the B*51:01 subtype (108 of 151, 71.5%), 39 of 151 (25.8%) the B*51:08 subtype, 2 of 151 (1.3%) the B*51:02 subtype, 1 of 151 (0.7%) the B*51:05 subtype, and 1 of 151 (0.7%) the B*51:07 subtype. We found that ocular involvement was statistically associated with HLA-B*51 positivity and with B*51:01 and B*51:08 subtypes (P < 0.05). We also found that disease severity was higher in HLA-B*51-positive patients than in negative patients, but without statistical significance (median Krause's index 5.1 vs 4.1, P > 0.05).

Conclusion

Here, we confirm a high frequency of the HLA-B*51 allele in our group of BS patients. B*51:01 and B*51:08 were found to be the most common subtypes, and an association of both subtypes with ocular involvement was also underlined.

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.

A rare case of Behcet's disease in Nepal: multisystem manifestations and diagnostic challenges

Behcet's disease (BD) is a chronic inflammatory disorder characterized by a relapsing and remitting course and multisystem involvement. The authors present a case report of a 20-year-old male who presented with bilateral knee joint pain, oral and genital ulcers, and papulopustular skin lesions. The patient's clinical history, physical examination, laboratory findings, and biopsy results were consistent with the diagnosis of BD. The patient tested positive for the HLA-B51 allele, confirming a genetic predisposition. The diagnosis was supported by a positive pathergy test and a skin biopsy showing vasculitis. The diagnostic criteria established by the international study group and the International Criteria for Behcet's Disease were fulfilled. Treatment consisted of colchicine, azathioprine, and topical corticosteroids. This case highlights the importance of recognizing the varied clinical presentations of BD and the need for a multidisciplinary approach to diagnosis and management. Early and accurate diagnosis is crucial to prevent severe complications and improve patient outcomes.

Advances in pathogenesis and treatment of ocular involvement in Behcet's disease

Behcet's disease (BD) is a chronic multi-systemic disease characterized by relapsing-remitting oral ulcers, genital ulcers, ocular inflammatory involvements, and numerous other systemic features. Ocular involvements are quite common in BD and may cause severe tissue damage and potentially blindness. Even though the pathogenesis of BD remains ambiguous, growing evidences have shown that genetic factors, environmental triggers and immunological abnormalities play significant roles in its development and progression. Novel biotherapies targeting IFN-γ, TNF-α and interleukins have been used in recent years. In this review, we mainly pay attention to the ocular involvement of BD, and discuss the current understanding of mechanisms and advances in therapeutic approaches, especially novel biologics. Finally, we discuss the management in patients with pregnancy.

Heat Shock Proteins in Behçet Syndrome

Behçet syndrome (BS) is a systemic vasculitis of unknown etiology that affects the skin, mucosa, joints, eyes, central nervous system, gastrointestinal system, arteries, and veins. It is generally believed to have a complex genetic background where both innate and adaptive immune systems are activated through environmental factors, such as infections, and auto-antigens. Heat shock proteins (HSPs) are highly conserved and immunogenic endogenous proteins that are thought to play both an enhancing and regulating role in several autoimmune and inflammatory diseases, such as rheumatoid arthritis, juvenile idiopathic arthritis, and Type I diabetes. There is evidence supporting the role of various microorganisms in BS, which may be using a common pathway to trigger or activate BS through molecular mimicry. The significant homology between microbial and human HSPs suggests that HSPs could serve as a common trigger. This review summarizes the work on the role of HSPs in the pathogenesis of BS. However, it remains unknown whether the HSPs detected in BS lesions play a causative role, their presence is a result of the ongoing inflammation, or they have a protective role against inflammation, as suggested in some other diseases.

[Diagnosis and Treatment of Neuro-Behçet: A Clinical Update]

Behçet's disease is a relapsing multisystemic inflammatory syndrome characterized by recurrent oral and/or genital ulcers, uveitis, arthritis, skin lesions, and gastrointestinal and neurological involvement. Neuro-Behçet corresponds to nervous system involvement and is one of the most severe complications of Behçet disease. It occurs in 3% to 30% of cases and is categorized into parenchymal (most common) or non-parenchymal disease. The most common manifestation of parenchymal neuro-Behçet is meningoencephalitis with involvement of the brainstem, where patients present with cranial neuropathies, encephalopathy, sensory-motor syndromes, epilepsy, or myelitis. The main non-parenchymal manifestation is cerebral venous thrombosis. Neuro-Behçet has a predominantly subacute course, with remission within weeks, or clinical progression in one third of the cases. The diagnosis is essentially clinical and diagnostic tests help to corroborate the suspicion, distinguish from differential diagnoses, and exclude complications. Brain magnetic resonance imaging allows the identification of acute lesions (hypointense or isointense on T2-weighted and hypointense on T1-weighted sequences) contrast-enhanced, and chronic lesions characterized by non-contrast enhanced small lesions and brainstem atrophy. If non-parenchymal involvement is suspected, cerebral veno-magnetic resonance imaging /computed tomography should be performed. Cerebrospinal fluid shows elevated proteinorachia and pleocytosis in parenchymal and no changes in non-parenchymal neuro-Behçet (except increased opening pressure). Outbursts of parenchymal disease should be treated with high dose intravenous corticosteroid therapy, with subsequent switch to oral corticoids, followed by biologic therapy, usually an anti-TNF. The treatment of cerebral venous thrombosis is controversial and may consist of a combination of corticosteroids and anticoagulation.

The complex HLA-E-nonapeptide in Behçet disease

Introduction

The knowledge of the aetiology of Behçet disease (BD), an immune-mediated vasculitis, is limited. HLA-B, mainly HLA-B51, and HLA-A molecules are associated with disease, but the ultimate cause of this association remains obscure. There is evidence that NK cells participate in the etiopathology of BD. NK cells have activator and inhibitor surface receptors, like the KIR and the NKG2 families. Classical HLA-class I molecules (A, B and C) are keys in the activity control of the NK because they are KIR ligands. Most NKG2 receptors bind HLA-E, which presents only nonapeptides derived from the signal peptide of other class-I molecules.

Objective

This study investigates the contribution of the pair HLA-E and ligand, nonapeptide derived from the 3-11 sequence of the signal peptides of class I classical molecules, to the susceptibility to BD.

Methods

We analyzed the frequency of the HLA-derivated nonapeptide forms in 466 BD patients and 444 controls and an HLA-E functional dimorphism in a subgroup of patients and controls. Results: In B51 negative patients, the frequency of VMAPRTLLL was lower (70.4% versus 80.0% in controls; P=0.006, Pc=0.04, OR=0.60, 95%CI 0.41-0.86), and the frequency of VMAPRTLVL was higher (81.6% versus 71.4% in controls; P=0.004, Pc=0.03, OR=1.78, 95%CI 1.20-2.63). In homozygosity, VMAPRTLLL is protective, and VMAPRTLVL confers risk. The heterozygous condition is neutral. There were no significant differences in the distribution of the HLA-E dimorphism.

Discussion

Our results explain the association of BD with diverse HLA-A molecules, reinforce the hypothesis of the involvement of the NK cells in the disease and do not suggest a significant contribution of the HLA-E polymorphism to disease susceptibility.

Inferior Vena Cava Thrombosis and Pulmonary Embolism in a Patient With Behcet Disease: A Rare Presentation

Behcet syndrome is a systemic vasculitic syndrome. Vascular involvement in Behcet syndrome affects both arterial and venous vascular systems, contributing to significant morbidity and mortality. However, diagnosing vascular lesions can be challenging due to their resemblance to common vascular diseases, leading to potential misdiagnoses. This case report emphasizes the importance of recognizing atypical manifestations of this disease to ensure a prompt and accurate diagnosis. This case report describes a unique presentation of Behcet syndrome in a 23-year-old male patient who presented with per rectal bleeding, abdominal distension, right quadrant abdominal pain, pleuritic chest pain, and fever. The patient also reported a history of recurrent oral and genital ulcers, skin lesions, and a previous episode of dural venous sinus thrombosis. Extensive investigations revealed the involvement of the inferior vena cava and right hepatic vein, representing an atypical vascular manifestation of Behcet syndrome. Prompt diagnosis by a multidisciplinary team led to appropriate treatment with cyclophosphamide and steroids, resulting in the resolution of vascular thrombosis. In this particular case, the patient presented with involvement of the inferior vena cava and right hepatic vein, a rare and unusual manifestation of the disease. This case highlights the diverse nature of vascular complications in Behcet syndrome and underscores the importance of considering this diagnosis in patients with unexplained vascular abnormalities. Overall, this case report highlights the importance of considering Behcet syndrome in the differential diagnosis of patients with unexplained vascular manifestations. It also emphasizes the need for a comprehensive clinical evaluation and collaborative approach to ensure timely and effective management.

Behçet disease in Latin American countries: A systematic literature review of demographic and clinical features, and HLA-B*51 allele frequency

OBJECTIVE

To describe the demographic and clinical features, as well as the frequency of the HLA-B*51 allele in Behçet disease (BD) patients in Latin American countries.

METHODS

A systematic literature review of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines was conducted without performing a meta-analysis. We included observational studies (cross-sectional or cohort) of BD patients fulfilling the International Study Group for BD classification criteria and reported the demographic, clinical, and laboratory features of the disease in adult patients.

RESULTS

Twelve studies were included in the SLR. Information from 532 patients across 5 Latin American countries was included for the analysis. Mean age at disease diagnosis was 33 years, 58.3% were female and 41.7% male; most patients were non-Caucasian. The most common clinical manifestations were recurrent oral ulcers and genital ulcers, followed by skin, eye, joint, neurological, gastrointestinal, vascular, and cardiac involvement. The prevalence of BD was described in 2 studies, 1 conducted in Brazil that reported a prevalence of .3/100,000 inhabitants, and another in Colombia with a prevalence of 1.1/100,000 inhabitants. The frequency of HLA-B*51 allele in BD patients was 38%, 30.1%, and 9% in Argentina, Brazil, and Mexico, respectively.

CONCLUSIONS

The prevalence of BD in the Latin American countries seems to be low, as well as the frequency of HLA-B*51 allele. However, the strength of association between HLA-B*51 and BD remains high in our population. The key clinical features of BD are like those reported in countries/regions where BD is endemic.

Behçet Syndrome

Behçet's syndrome is a systemic vasculitis affecting arteries and veins of all sizes as well as recurrent oral, genital, and intestinal ulcers, skin lesions, predominantly posterior uveitis, and parenchymal brain lesions. These can be present in various combinations and sequences over time and diagnosis is made by recognizing the manifestations, as there are no diagnostic biomarkers or genetic tests. Treatment modalities include immunomodulatory agents, immunosuppressives and biologics, tailored according to prognostic factors, disease activity, severity, and patients' preferences.

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.

Case of elderly onset possible neuro-Behçet's disease with HLA-B51 homozygosity

Behçet's disease commonly affects 20-40-year-old men and shows ophthalmo-dermatological manifestations. Here, we report a man in his 70s with acute onset of dysarthria, dysphagia and hemiplegia showing brainstem and subcortical lesions, which responded to steroid and colchicine therapy. He had a history of uveitis and was homozygous for the human leucocyte antigen-B51 allele, and we clinically diagnosed him with acute neuro-Behçet's disease. Old-age onset neuro-Behçet's disease is uncommon, and as far as we know, this is the oldest case of the first attack of neuro-Behçet's disease. Clinicians should consider Behçet's disease even for elderly patients.

Frail Silk: Is the Hughes-Stovin Syndrome a Behçet Syndrome Subtype with Aneurysm-Involved Gene Variants?

Hughes-Stovin syndrome is a rare disease characterized by thrombophlebitis and multiple pulmonary and/or bronchial aneurysms. The etiology and pathogenesis of HSS are incompletely known. The current consensus is that vasculitis underlies the pathogenic process, and pulmonary thrombosis follows arterial wall inflammation. As such, Hughes-Stovin syndrome may belong to the vascular cluster with lung involvement of Behçet syndrome, although oral aphtae, arthritis, and uveitis are rarely found. Behçet syndrome is a multifactorial polygenic disease with genetic, epigenetic, environmental, and mostly immunological contributors. The different Behçet syndrome phenotypes are presumably based upon different genetic determinants involving more than one pathogenic pathway. Hughes-Stovin syndrome may have common pathways with fibromuscular dysplasias and other diseases evolving with vascular aneurysms. We describe a Hughes-Stovin syndrome case fulfilling the Behçet syndrome criteria. A MYLK variant of unknown significance was detected, along with other heterozygous mutations in genes that may impact angiogenesis pathways. We discuss the possible involvement of these genetic findings, as well as other potential common determinants of Behçet/Hughes-Stovin syndrome and aneurysms in vascular Behçet syndrome. Recent advances in diagnostic techniques, including genetic testing, could help diagnose a specific Behçet syndrome subtype and other associated conditions to personalize the disease management.

Single nucleotide polymorphisms rs7799039 and rs2167270 in leptin gene and elevated serum levels of adiponectin predispose Iranians to Behçet's disease

BACKGROUND

Behçet's Disease (BD) is a chronic autoimmune disease with unknown etiology. Adipokines due to their roles in the regulation of immune responses might be important in the induction and progression of BD.

SUBJECTS AND METHODS

This case-control study included 340 patients with BD and 310 healthy controls. Single nucleotide polymorphisms (SNPs) in adiponectin (rs266729 and rs1501299) and leptin (rs7799039 and rs2167270) genes were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and serum levels of adipokines were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

A higher frequency of leptin rs7799039 GG, AG, and AG +GG genotypes and G allele was revealed in patients. Besides, patients had more leptin rs2167270 AG and AG +AA genotypes and A allele. Furthermore, rs2167270 AA genotype and A allele were more frequently seen in total and female patients who had genital aphthous. Patients had significantly more serum levels of adiponectin while those with genital aphthous had significantly more leptin levels. No significant association was observed between genotypes and alleles of adiponectin SNPs and BD.

CONCLUSION

Our findings indicated that leptin gene polymorphisms might predispose Iranian individuals to BD. Besides, elevated serum levels of adiponectin might facilitate BD pathogenesis.

The Role of Colchicine in Different Clinical Phenotypes of Behcet Disease

PURPOSE

Behcet disease (BD) is a multisystemic disorder characterized by variable clinical manifestations that affect nearly all systems and organs. Colchicine, an alkaloid plant extract, is considered as the first-line therapy for gout, pericarditis, and familial Mediterranean fever. However, the role of colchicine in the treatment of different clinical phenotypes of BD has not been clearly described. This narrative review summarizes the clinical use of colchicine in BD.

METHODS

All relevant literature from 1980 to March 2021 was searched in PubMed, MEDLINE, and Cochrane Library. The Medical Subject Heading terms and related words that were searched are as follows: Behcet's disease, Behcet's syndrome, BD, colchicine, management, treatment, and therapy.

FINDINGS

BD is an autoimmune systemic vasculitis with various clinical phenotypes, with involvement of skin mucosa, joints, eyes, and gastrointestinal, vascular, and neurologic systems. Colchicine has been used for centuries, acts by binding to tubulin to prevent the mitotic process, and has anti-inflammatory, antitumor, and antifibrotic properties. Colchicine has been reported to be an effective option for the treatment of skin, mucosal, and joint involvement in patients with certain BD clinical phenotypes.

IMPLICATIONS

Colchicine reduces the severity of certain clinical phenotypes and may improve the overall disease activity index in patients with BD. More randomized clinical trials are needed to confirm the value of colchicine in the treatment of BD, and further elucidation of the mechanisms is also needed, which may reveal new application of colchicine that has been used for centuries.

Behcet disease: an undifferentiating and complex vasculitis

Behçet Disease is a relapsing and remitting variable vessel vasculitis characterized by recurrent mucocutaneous ulcers that can involve almost every organ system in the body. Indeed, the presence of recurrent oral or genital ulcers with other auto-inflammatory symptoms should raise suspicion for this elusive disease. It is unique among the vasculitides in that it can affect vessels of small, medium, and large size and tends to involve venous rather than arterial circulation, and its effects on the pulmonary venous circulation are particularly notable for their role in disease mortality. Classically seen in Mediterranean, Middle-Eastern, and eastern Asian countries, and relatively rare in the United States, prevalence has been increasing, prompting an increased need for internists to be aware of Behcet's clinical presentation and treatment. As early recognition and diagnosis of the disease is key to successful treatment and better prognosis, this review provides a brief summary of the current etiological theories, important clinical manifestations, and treatments including newer biologic alternatives.

Mucocutaneous manifestations of Behçet's disease: Pathogenesis and management from perspectives of vasculitis

Behçet's disease (BD) is a systemic inflammatory disorder characterized by vasculitis affecting blood vessels of any caliber or type. It can present with a wide spectrum of vasculitic lesions, including erythema nodosum-like lesions and retinal vasculitis, and may also lead to larger vessel diseases, such as aortic aneurysm and deep vein thrombosis. The full etiology of BD remains unclear, but it is considered a polygenetic disease with multiple genetic risk factors that promote immune dysregulation and thrombophilia. Inflammation can be triggered by environmental factors, such as bacteria or viruses, and the dysregulation of innate and adaptive immune cell subsets. Neutrophils and lymphocytes are the primary players involved in BD pathogenesis, with specific innate (i.e., neutrophil-derived reactive oxygen species and neutrophil extracellular traps) and adaptive (i.e., anti-endothelial cell antibodies) processes inducing endothelial cell activation and chemotaxis of inflammatory cells, leading to coagulation and vasculitis. These inflammation-induced vasculitic or vasculopathic features are observed in most mucocutaneous BD lesions, although vasculitis per se is often pathologically evident only during a brief period of the disease process. Due to the multifactorial nature of BD-associated inflammation, broad-spectrum anti-inflammatory medications, including glucocorticoids and immunosuppressive drugs, have been the mainstay for managing BD. In addition, inhibitors of interleukin (IL)-1, tumor necrosis factor (TNF)-α, and IL-17, which target innate and adaptive immune functions dysregulated in BD, have emerged as promising new therapeutics. In this review, we discuss the muco-cutaneous manifestations of BD by focusing on the underlying vasculitic components in their pathologies, as well as the current array of treatment options.

The neutrophil: A key resourceful agent in immune‐mediated vasculitis

The term "vasculitis" refers to a group of rare immune-mediated diseases characterized by the dysregulated immune system attacking blood vessels located in any organ of the body, including the skin, lungs, and kidneys. Vasculitides are classified according to the size of the vessel that is affected. Although this observation is not specific to small-, medium-, or large-vessel vasculitides, patients show a high circulating neutrophil-to-lymphocyte ratio, suggesting the direct or indirect involvement of neutrophils in these diseases. As first responders to infection or inflammation, neutrophils release cytotoxic mediators, including reactive oxygen species, proteases, and neutrophil extracellular traps. If not controlled, this dangerous arsenal can injure the vascular system, which acts as the main transport route for neutrophils, thereby amplifying the initial inflammatory stimulus and the recruitment of immune cells. This review highlights the ability of neutrophils to "set the tone" for immune cells and other cells in the vessel wall. Considering both their long-established and newly described roles, we extend their functions far beyond their direct host-damaging potential. We also review the roles of neutrophils in various types of primary vasculitis, including immune complex vasculitis, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, Takayasu arteritis, and Behçet's disease.

Sex-specific analysis in Behçet's disease reveals higher genetic risk in male patients

OBJECTIVES

Behçet's disease tends to be more severe in men than women. This study was undertaken to investigate sex-specific genetic effects in Behçet's disease.

METHODS

A total of 1762 male and 1216 female patients with Behçet's disease from six diverse populations were studied, with the majority of patients of Turkish origin. Genotyping was performed using an Infinium ImmunoArray-24 BeadChip, or extracted from available genotyping data. Following imputation and extensive quality control measures, genome-wide association analysis was performed comparing male to female patients in the Turkish cohort, followed by a meta-analysis of significant results in all six populations. In addition, a weighted genetic risk score for Behçet's disease was calculated and compared between male and female patients.

RESULTS

Genetic association analysis comparing male to female patients with Behçet's disease from Turkey revealed an association with male sex in HLA-B/MICA within the HLA region with a GWAS level of significance (rs2848712, OR = 1.46, P = 1.22 × 10-8). Meta-analysis of the effect in rs2848712 across six populations confirmed these results. Genetic risk score for Behçet's disease was significantly higher in male compared to female patients from Turkey. Higher genetic risk for Behçet's disease was observed in male patients in HLA-B/MICA (rs116799036, OR = 1.45, P = 1.95 × 10-8), HLA-C (rs12525170, OR = 1.46, P = 5.66 × 10-7), and KLRC4 (rs2617170, OR = 1.20, P = 0.019). In contrast, IFNGR1 (rs4896243, OR = 0.86, P = 0.011) was shown to confer higher genetic risk in female patients.

CONCLUSIONS

Male patients with Behçet's disease are characterized by higher genetic risk compared to female patients. This genetic difference, primarily derived from our Turkish cohort, is largely explained by risk within the HLA region. These data suggest that genetic factors might contribute to differences in disease presentation between men and women with Behçet's disease.

Neuro-Behcet's syndrome: Case report and literature review

Behcet's disease (BD) is a multisystem, autoimmune vasculitis disorder affecting small, medium, and large blood vessels, with poorly understood pathogenesis. It commonly presents with recurrent aphthous ulcers, genital ulcers, skin lesions, and bilateral uveitis. Neurological symptoms are present in less than 10% of cases and develop, on average, 5-6 years after the first non-neurological symptoms. This presentation, known as Neuro-Behcet's disease (NBD), is associated with a worse prognosis of BD. Treatment for NBD is dependent on the severity of symptoms and the presence of other systemic manifestations but often initially involves glucocorticoids and a disease-modifying agent. This case report presents a 44-year-old female patient, previously diagnosed with BD, who presented with neurological symptoms and MRI findings consistent with NBD.

IL-1 and autoinflammatory disease: biology, pathogenesis and therapeutic targeting

Over 20 years ago, it was first proposed that autoinflammation underpins a handful of rare monogenic disorders characterized by recurrent fever and systemic inflammation. The subsequent identification of novel, causative genes directly led to a better understanding of how the innate immune system is regulated under normal conditions, as well as its dysregulation associated with pathogenic mutations. Early on, IL-1 emerged as a central mediator for these diseases, based on data derived from patient cells, mutant mouse models and definitive clinical responses to IL-1 targeted therapy. Since that time, our understanding of the mechanisms of autoinflammation has expanded beyond IL-1 to additional innate immune processes. However, the number and complexity of IL-1-mediated autoinflammatory diseases has also multiplied to include additional monogenic syndromes with expanded genotypes and phenotypes, as well as more common polygenic disorders seen frequently by the practising clinician. In order to increase physician awareness and update rheumatologists who are likely to encounter these patients, this review discusses the general pathophysiological concepts of IL-1-mediated autoinflammation, the epidemiological and clinical features of specific diseases, diagnostic challenges and approaches, and current and future perspectives for therapy.

Genetics in Behcet's Disease: An Update Review

Behcet's disease (BD) is one of the most vision-threatening clinical entities of uveitis. Although the etiopathogenesis of BD remains obscure, accumulating evidence has demonstrated that both genetic and environmental factors may contribute to the development of BD. Genome-wide association studies (GWAS) and candidate association studies have identified several genetic variants strongly associated with BD, including variants in human leukocyte antigen (HLA) -A02, -A03, -A24, -A26, -A31, -B15, -B27, -B35, -B49, -B51, -B57, -B58, -C0704, CIITA, ERAP1, MICA, IL1A-IL1B, IL10, IL12, IL23R, IL-23R/IL-12RB2, IL1RL1-IL18R1, STAT4, TFCP2L1, TRAF5, TNFAIP3, CCR1/CCR3, RIPK2, ADO-ZNF365-EGR2, KLRC4, LACC1, MEFV, IRF8, FUT2, CEBPB-PTPN1, ZMIZ1, RPS6KA4, IL10RA, SIPA1-FIBP-FOSL1, VAMP1, JRKL/CTCN5, IFNGR1 and miRNA-146a. Epigenetic modifications are also reported to play essential roles in the development of BD, including DNA methylation and histone modification. We review here the recent advances in the genetic and epigenetic factors associated with the BD pathogenesis.

[Thoracic manifestations of Behcet's disease]

Behcet's disease (BD) is a multisystemic vasculitis involving arteries and veins of all sizes. While joint and dermatological manifestations are the most common features of BD and are associated with a good prognosis; vascular involvement, remains the principal cause of death. Arterial manifestations occur in 5-10% of cases and manifest as occlusion/thrombosis or aneurysms. Arterial aneurysms are likely multiple and the most common sites are pulmonary arteries, aorta and arteries of lower limbs. Parenchymal involvement is less frequent and may manifest as consolidation or nodules, which may evolve to excavation. Aneurysms may occur at the sites of arterial puncture; then, non-traumatic techniques are favored. Patients with arterial manifestations may present with fever and increased inflammatory markers. Artery damage is rare, serious, and may result in massive hemoptysis. The prognosis of pulmonary artery aneurysms is severe (mortality estimated up to 26%) but has been improved by earlier diagnosis and the introduction of immunosuppressants. Treatment of severe arterial manifestations is based on high-dose corticosteroids along with cyclophosphamide or anti-TNF antagonists. Anticoagulation could be added to immunosuppressants in case of venous thrombosis if a coexisting pulmonary aneurysm is ruled out. Endovascular treatment should be performed in case of severe symptomatic pulmonary aneurysms, along with an adequate medical management. Long-term maintenance therapy of these severe forms is of paramount importance because of relapse risk (40% at five years).

Parental uveitis causes elevated hair loss in offspring of C57BL/6J mice

Our previous study demonstrated that parental uveitis in a susceptible population can cause hair loss and increase the susceptibility to experimental autoimmune uveitis (EAU) in offspring. However, it is unclear whether parental uveitis affects the development of offspring in an EAU-moderate-susceptible population. Herein, moderate-susceptible C57BL/6J mice were immunized with inter-photoreceptor retinoid binding protein (IRBP) 651-670 to develop EAU and were kept together for mating. Gross examination and histopathological changes of the offspring gestated with parental uveitis were observed to evaluate the impact of parental uveitis on the development of the offspring. Differentially expressed genes (DEGs) were screened by RNA sequencing in the affected skin and eyeball of the offspring on postnatal day 27. Adult offspring were injected 75 μg IRBP_651-670 to evaluate their susceptibility to EAU. Gross examination in the offspring revealed hair loss on postnatal days 11-31. Histopathological observation showed increased melanin granules and hair follicles of skin in the affected offspring with hair loss. Gene Ontology (GO) analysis in the skin revealed differential expression of genes involved in the mitotic cell cycle, response to endogenous stimulus, hair follicle development, and hair cycle. The DEGs in the skin were predominately associated with the cell cycle and peroxisome proliferator-activated receptor (PPAR) signaling pathway. The GO enrichment analysis in the eyeball showed differential expression of genes involved in the nervous system development, camera-type eye photoreceptor cell differentiation, neuron projection morphogenesis, axon development, and calcium-induced calcium release activity; enriched pathways included the circadian entrainment and glutamatergic synapses. No increased susceptibility to EAU in offspring gestated from parental remitting EAU was observed at a low-dose 75 μg IRBP induction. These results suggested that parental uveitis in a moderate-susceptible population could affect the skin development and DEG profiles of skin and eyeball related to the response to endogenous stimulus, the PPAR signaling pathway, and glutamatergic synapse, which provides the molecular evidence to explain the influence of parental uveitis on offspring development.