Characteristics and phenotype heterogeneity in late-onset Behçet's syndrome: a cohort from a referral center in China

Clinical phenotypes of adult-onset Behçet's syndrome: a comprehensive cross-sectional study in China

Behçet's syndrome (BS) is a variant vasculitis that can involve multiple organs with inflammatory manifestations. This study aimed to provide a more comprehensive analysis of the clinical phenotypes and characteristics of BS patients. We enrolled 2792 BS patients referred from China nationwide to Huadong Hospital Affiliated to Fudan University from October 2012 to December 2022. Detailed assessments of demographic information, clinical manifestations, laboratory results, gastroscopy, and medical imaging were conducted. Cluster analysis was performed based on 13 variables to determine the clinical phenotypes, and each phenotype was characterized according to the features of BS patients. A total of 1834 BS patients were included, while 958 invalid patients were excluded. The median age at onset was 31 years (IQR, 24-40 years), and the median disease duration was 10 years (IQR, 5-15 years). Eight clusters were identified, including mucocutaneous (n =  655, 35.7%), gastrointestinal (n =  363, 19.8%), articular (n =  184, 10%), ocular (n =  223, 12.2%), cardiovascular (n =  119, 6.5%), neurological (n =  118, 6.4%), vascular (n =  114, 6.2%), and hematological phenotype (n =  58, 3.2%). Ocular (RR =  1.672 (95% CI, 1.327-2.106); P <  0.001), gastrointestinal (RR = = 1.194 (95% CI, 1.031-1.383); P =  0.018), cardiovascular (RR = = 2.582 (95% CI, 1.842-3.620); P <  0.001), and vascular (RR = = 2.288 (95% CI, 1.600-3.272); P <  0.001) involvement were more prevalent in male BS patients, while the hematological (RR =  0.528 (95% CI, 0.360-0.776); P =  0.001) involvement was more common among female patients. BS presents significant heterogeneity and gender differences. The eight phenotypes of BS patients we propose hold the potential to assist clinicians in devising more personalized treatment and follow-up strategies. Key Points • This cluster analysis divided adult-onset BS into eight clinical phenotypes. • BS demonstrates a high level of clinical heterogeneity and gender differences. • Hematologic phenotypes of BS present distinctive clinical characteristics.

Behçet's syndrome

Behçet's syndrome is a rare, chronic multisystemic inflammatory disorder also known as the Silk Route disease due to its geographical distribution. Behçet's syndrome is a multifactorial disease and infectious, genetic, epigenetic, and immunological factors contribute to its pathogenesis. Its heterogeneous spectrum of clinical features include mucocutaneous, articular, ocular, vascular, neurological, and gastrointestinal manifestations that can present with a relapsing and remitting course. Differential diagnosis is often hampered by the non-specific clinical presentation and the absence of laboratory biomarkers or pathognomonic histological features. The therapeutic approach is tailored on the basis of patient-specific manifestations and relies on glucocorticoids, colchicine, and traditional and biological immunosuppressants. Despite progress in the knowledge and management of the disease, unmet needs in diagnostics, monitoring, prediction, and treatment personalisation challenge clinical practice, making Behçet's syndrome a complex disorder associated with an increased risk of morbidity.

Cluster analysis as a clinical and research tool in Behçet's syndrome

PURPOSE OF REVIEW

The purpose of this review was to comprehensively summarize recent phenotype research findings in Behçet's syndrome.

RECENT FINDINGS

Cluster analysis has recently been employed as a phenotype research tool in Behçet's syndrome. Studies reported different clustering patterns caused by biological variation and some degree of artificial heterogeneity. However, some clusters were more consistent than others: 1) oral ulcers, genital ulcers, and skin lesions 2) oral ulcers, genital ulcers, skin lesions, and arthritis 3) oral ulcers, genital ulcers, skin lesions, and uveitis 4) oral ulcers, genital ulcers, skin lesions, and gastrointestinal involvement. A number of loci suggestive of differential risk for individual disease manifestations were proposed. Peripheral blood gene expression profile and plasma proteome exhibited significant differences in patients with different organ involvements and were able to differentiate between disease phenotypes. However, these observations require further validation and functional studies.

SUMMARY

Clustering patterns in Behçet's syndrome is highly heterogeneous. Artificial heterogeneity might obscure the true biological variation of disease expression. Preliminary genetic, transcriptomic and proteomic data suggest that different pathogenetic mechanisms may operate in different phenotypes of Behçet's syndrome.

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.

Clinical Characteristics and Outcomes of Mexican Patients With Behçet's Syndrome

OBJECTIVE

The aim of this study was to describe the clinical characteristics and outcomes of Mexican patients with Behçet syndrome (BS) from a single center.

METHODS

This medical records review study included patients with established BS diagnosis, followed up in a tertiary care center in Mexico City from 2000 to 2020. Demographics, clinical characteristics, laboratory and imaging studies, disease activity, damage, treatment, and outcomes were assessed and compared according to sex and with other international cohorts. Descriptive statistics were used, and differences between groups were evaluated using the χ2 or Mann-Whitney U tests.

RESULTS

Thirty-eight patients were included, 23 (60%) women and 15 (40%) men; the median age at BS diagnosis was 33 years (range, 24-39 years). The most frequent manifestations at diagnosis were recurrent oral and genital ulcers in 34 (89%) and 29 (76%), respectively, musculoskeletal in 21 (55%), and cutaneous in 15 (39%). The most frequent phenotype was the joint involvement. Treatment comprised prednisone in all, colchicine (24 [63%]), pentoxifylline (12 [32%]), and thalidomide (10 [26%]). During a median follow-up time of 12.5 years (range, 7-23 years), relapses were frequent (97%), severe infections were present in 5 patients (13%), and 2 patients (5%) died due to sepsis and pneumonia. Men showed a higher frequency of arterial hypertension (47% vs. 13%, p = 0.03) and thrombosis (20% vs. 0, p = 0.05), and a lower frequency of genital ulcers (40% vs. 78%, p = 0.03) than women.

CONCLUSIONS

This cohort of Mexican patients with BS showed a predominance of female sex, joint involvement phenotype, frequent relapses, and favorable outcomes. Differences in comorbidities and clinical manifestations were identified according to sex.

Ocular Behçet Disease-Clinical Manifestations, Treatments and Outcomes According to Age at Disease Onset

Behçet disease (BD) is a multisystemic disease that commonly involves the eyes. Although it affects patients in all age groups, data on ocular disease by age of onset are limited. This retrospective, multicenter study aimed to compare epidemiology, systemic and ocular manifestations, treatments and outcomes between three age groups: juvenile (<18 years), adult (18-39 years) and late (≥40 years) disease onset. The study included 175 ocular BD patients (303 eyes) from Israel and Palestine: juvenile-onset (n = 25, 14.3%), adult-onset (n = 120, 68.6%) and late-onset (n = 30, 17.1%). Most patients in all groups were male. Systemic manifestations were similar in all groups. Systemic co-morbidities were more common in late-onset patients. Bilateral panuveitis was the most common ocular manifestation in all patients. Non-occlusive retinal vasculitis, peripheral vessel occlusions, cataract and elevated intraocular pressure were found more commonly among juvenile-onset eyes. Anterior uveitis and macular ischemia were most common among late-onset eyes, while branch retinal vein occlusion was most common in adult and late-onset eyes. All patients were treated with corticosteroids. Methotrexate, immunomodulatory combinations and biologic treatments were more commonly used for juvenile-onset patients. All groups had a similar visual outcome. Our study showed that patients with ocular BD have varied ocular manifestations and require different treatments according to age of disease onset, but visual outcome is similar.

Vascular Behçet syndrome: from pathogenesis to treatment

Behçet syndrome is a rare, chronic inflammatory disease of unknown aetiopathogenesis, most commonly presenting with mucocutaneous and ocular manifestations. Vascular involvement, most frequently superficial vein and deep vein thrombosis, can occur in up to 50% of patients with Behçet syndrome. Venous thrombosis at atypical sites (inferior and superior vena cava, suprahepatic veins with Budd-Chiari syndrome, portal vein, cerebral sinuses and right atrium and/or ventricle) and arterial involvement (mostly in situ thrombosis and aneurysms of the pulmonary arteries, as well as aneurysms of the abdominal aorta, and peripheral and visceral arteries) are also unique features of Behçet syndrome. Behçet syndrome is considered a natural model of inflammation-induced thrombosis in humans, with an impaired immune-inflammatory response rather than traditional cardiovascular risk factors contributing to thrombogenesis. Specifically, neutrophil hyperactivation and neutrophil-mediated mechanisms of damage directly promote endothelial dysfunction, platelet activation and thrombogenesis in Behçet syndrome. This unusual pathogenesis directly determines the treatment approach, which relies mostly on immunosuppressants rather than anticoagulants for treatment of thrombosis and for secondary prevention. This Review discusses the main histopathological, pathogenetic and clinical aspects of vascular Behçet syndrome, addressing their implications for therapeutic management. Future perspectives in terms of pathogenetic studies, disease monitoring and treatment strategies are also discussed.