Behçet's disease: general concepts and recent advances

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.

Comparing biologic options for the management of Behcet's disease-related uveitis

INTRODUCTION

Behçet's disease (BD) associated uveitis occurs in approximately 50-70% of the patients. Ocular involvement in BD may induce a severe affection of visual function, leading to a considerable decrease in patients' quality of life. The risk for severe visual loss increases when the ocular posterior segment is involved and in patients with no adequate treatment.

AREAS COVERED

Monoclonal tumor necrosis factor (TNF) biotechnological inhibitors represent a relatively recent milestone for the treatment of non-infectious uveitis (NIU) also in BD patients. In addition to TNF inhibitors, further biologic agents have been increasingly proposed for multi-recalcitrant cases, as for interleukin (IL)-1 and IL-6 inhibitors. However, evidence on these new opportunities requires to be widened in the next future.

EXPERT OPINION

Joining the forces for scientific efforts is essential to quickly obtain solid acquisitions useful for the everyday clinical practice. To this end, the Auto-Inflammatory Disease Alliance (AIDA) Network has recently supported the development of an international registry dedicated to NIU and other inflammatory ocular involvement observed in BD patients. This will be essential to resolve current and future unmet needs burdening the everyday clinical practice.

Adamantiades-Behçet disease: from clinical heterogeneity to diagnosis during the COVID-19 pandemic

Adamantiades-Behçet Disease (ABD) is a systemic disease with vasculitis, characterised by recurrent oral aphthosis and ocular, cutaneous, articular, vascular, cardiopulmonary manifestations and it is mainly found in the territories of the antique "silk road. ABD pathogenesis remains unknown although genetic, infectious and environmental factors seem to be implicated in the development of the disease, which is considered an auto-inflammatory condition. COVID-19 infection can present some symptoms, in particular at the level of oral and pulmonary mucosa, which require a differential diagnosis with ABD. Furthermore, the immunological alterations of this disease, and the drugs used for its treatment could influence the infection by COVID-19, and its clinical evolution. Nevertheless, vaccination anti-COVID-19 is recommended in ABD patients. The most commonly used diagnostic criteria for ABD are those established in 2014 by the International Team for the Revision of the International Criteria for BD (ITR-ICBD). Furthermore, criteria for disease severity according to the Overall Damage Index of Behçet's syndrome (BODI) have recently been proposed in order to quantify the severity of the disease as well as the evolution during follow-up. In ABD patients it is mandatory to investigate on the presence of active/latent tuberculosis, because of the common organ involvement, such as eyes and bowel. ABD has a high morbidity and low mortality, sometimes linked to the rupture of an arterial aneurysm and/or neurological complications. This article is based on a general review on ABD ranging from the history of ABD to possible causes and clinical manifestations. A specific section has been dedicated to the COVID-19 pandemic.

Retinal microvasculature features in patients with Behcet's disease: a systematic review and meta-analysis

This meta-analysis aimed to analyze retinal microvasculature features in eyes with Behçet's disease (BD) using optical coherence tomography angiography (OCTA). Electronic databases, including PubMed, Web of Science, Embase, and Cochrane Library, were comprehensively searched for published studies comparing retinal microvasculature characteristics between eyes with BD and controls. Continuous variables were calculated using the mean difference (MD) with 95% confidence interval (CI). Review Manager software (version 5.30) was used to conduct statistical analysis. A total of 13 eligible studies involving 599 eyes with BD and 622 control eyes were included in the meta-analysis. The pooled results showed that the macular whole enface superficial and deep vessel density (VD) values measured by OCTA were significantly lower in eyes with BD than in control eyes (superficial VD: MD = - 3.05, P < 0.00001; deep VD: MD = - 4.05, P = 0.0004). The foveal superficial and deep VD values were also significantly lower in the BD group than in the control group (superficial VD: MD = - 1.50, P = 0.009; deep VD: MD = - 4.25, -  = 0.03). Similarly, the analysis revealed a significant reduction in the parafoveal superficial and deep VD in eyes with BD than in control eyes (superficial VD: MD =  - 3.68, P < 0.00001; deep VD: MD = - 4.95, P = 0.0007). In addition, the superficial and deep foveal avascular zones (FAZs) were significantly larger in patients with BD than in controls (superficial FAZ: MD = 0.06, P = 0.02; deep FAZ: MD = 0.12, P = 0.03). The present meta-analysis found that macular whole enface VD, foveal VD, and parafoveal VD were lower in eyes with BD, and the FAZ was larger in patients with BD. The findings suggest that OCTA can assist clinicians in diagnosing and monitoring the status of patients with BD.

In-vitro immunomodulatory effects of nicotine on Nitric Oxide, interleukin 1β and interleukin 37 production in human peripheral blood mononuclear cells (PBMC) from patients with Behçet disease

Behçet's disease is a chronic systemic inflammatory disorder associated with a cytokine profile disruption and increased nitric oxide levels. In our current study we sought to evaluate the in-vitro modulatory effect of nicotine, the principal alkaloid of tobacco, on nitric oxide (NO), interleukin 1β (IL-1β) and interleukin 37 (IL-37) production during Behçet's disease. Peripheral blood mononuclear cells cultures were performed with or without nicotine (200 μg/ml). Culture supernatants were harvested after 24 h of incubation. NO, IL-1β and IL-37 measurements were, respectively, performed by modified Griess method and ELISA sandwich. Our results showed that nicotine significantly reduced NO and IL-1β levels in patients with Behçet's disease, while it increased IL-37 production. Our results showed no sex differences in the effects of nicotine on the production of nitric oxide and IL-1β nor IL-37 in PBMC of patients. Our findings suggest that nicotine may provide a potential therapeutic strategy targeting inflammation during Behçet's disease.

[Behçet's disease : Description and analysis of a French single-center retrospective study of 51 patients]

PURPOSE

To evaluate if the presence of uveitis in Behçet's disease (BD) is associated with a particular clinical phenotype and to analyze the prognostic impact of a missed diagnosis of BD at the time the uveitis is diagnosed.

MATERIEL AND METHODS

Ophthalmologic and systemic clinical features of 51 patients with BD were recorded retrospectively. We compared the clinical phenotype of patients with ocular manifestations with those without ocular manifestations. The patients were divided into two groups depending on the progression of their visual acuity: "decreased visual acuity" versus "stable or improved visual acuity."

RESULTS

In the group of patients with ocular involvement, there was a mean 2.3 systemic manifestations, vs. 3.2 in the group without ocular manifestations (P=0.004). When BD was diagnosed prior to the onset of uveitis, we counted fewer patients in the "decreased visual acuity" group in comparison with the patients who had no prior diagnosis of BD at the onset of the uveitis (91.3% in the "decreased visual acuity" group, P=0.04). The time before initiation of immunosuppressive treatment or a biological agent was shorter for these patients (4.4 vs. 39.3 months, P=0.007).

CONCLUSION

It appears that different phenotypes exist according to whether or not the BD patient has ocular involvement. Moreover, the visual prognosis is better if the uveitis occurs in patients who have already been diagnosed with BD, due to earlier initiation of immunosuppressive therapy.

[Ocular manifestations of Behçet's disease]

INTRODUCTION

Behçet's disease is a systemic inflammatory disease. Ocular involvement is an important diagnostic criterion, and this disease may be associated with severe visual loss.

PURPOSE

The goal of this study was to specify the epidemiological, clinical and therapeutic features of ocular involvement in patients with Behçet's disease and to identify risk factors for poor visual outcomes.

METHODS

A retrospective study was performed in 93 patients diagnosed with ocular Behçet's disease over a period of 9 years. Epidemiological, clinical, and therapeutic data was obtained from medical records and analyzed retrospectively. Poor visual outcome was defined as visual acuity limited to light perception without projection or no light perception.

RESULTS

The male:female ratio was 1.9. The mean age was 34.5 years. Ocular involvement was the presenting sign in 4%, bilateral in 61% and active in 68.8%. Uveitis was the most common presentation (57%), dominated by panuveitis, followed by retinal vasculitis (51.6%) and papilledema (10.7%). Maculopathy (26.8%) and cataract (18.2%) were the most common complications. Twenty patients (21.5%) had no light perception or light perception without projection. Treatment was based on corticosteroids in combination with immunosuppressive therapy (Azathioprine) in 55.9% of cases. Our study indicates a significant association of male gender and panuveitis with a poor visual outcome.

CONCLUSION

Ocular involvement in Behçet's disease is frequent and serious, which may lead to blindness. Male gender and panuveitis were predictors of poor visual prognosis.

Long-term efficacy of early infliximab-induced remission for refractory uveoretinitis associated with Behçet's disease

BACKGROUND

To evaluate long-term efficacy of infliximab (IFX) in refractory uveoretinitis associated with Behçet's disease (BD) depending on uveoretinitis duration.

METHODS

Records of 16 patients with BD (32 eyes) followed for >5 years after starting IFX, were retrospectively reviewed. Long-term efficacy was compared between patients with short duration (≤18 months, n=7) versus long duration (>18 months, n=9) of their uveoretinitis prior to starting IFX.

RESULTS

The median follow-up after starting IFX was 132 months (76-146 months). Mean frequency of attacks and the 1-year Behçet's Disease Ocular Attack Score 24 decreased significantly over 10 years. Overall, the percentage of eyes with a best-corrected visual acuity (BCVA) ≥1.0 increased from 47% at baseline to 59% at 5 years; the percentage of eyes with a BCVA ≤0.1 was 19% at both baseline and 5 years. The frequency of ocular attacks decreased similarly in both short duration and long duration groups; however, the percentage of eyes with a BCVA ≥1.0 at 5 years was 100% in the short duration group versus 28% in the long duration group. IFX was discontinued in four patients with an excellent response to IFX therapy; all were young male patients in the short duration group with good BCVA bilaterally, and none had inflammatory recurrences over a median follow-up of 56 months off IFX.

CONCLUSION

Initiation of IFX therapy in patients with BD within 18 months of their uveoretinitis onset was more effective in maintaining good BCVA than after 18 months.

Evaluation of disease activity in uveoretinitis associated with Behçet's disease

Behçet's disease is a multi-organ inflammatory disorder with systemic vasculitis of unknown etiology. Ocular lesions occur in about 70% of patients with Behçet's disease, and it is more frequent and severe in men. The frequency of ocular inflammatory attacks has been used as a main outcome measure to assess the efficacy of therapy on uveoretinitis in patients with Behçet's disease. The ocular Behçet's disease research group of Japan have recently proposed a new scoring system, Behçet's disease ocular attack score 24 (BOS24), to assess the disease activity of ocular Behçet's disease. This review highlights the efficacy and application of the BOS24 scoring system in clinical practice for patients with ocular Behçet's disease. In addition, a new semi-quantitative scoring system to evaluate the degree of retinal vascular leakage on fluorescein angiography reported by our group is described.

Type I Interferon Therapy Limits CNS Autoimmunity by Inhibiting CXCR3-Mediated Trafficking of Pathogenic Effector T Cells

Type I interferons (IFNs) have therapeutic potential in CNS autoimmune diseases, such as uveitis, but the molecular mechanisms remain unclear. Using a T cell-transfer model of experimental autoimmune uveitis (EAU), we found that IFN-α/β treatment inhibited the migration of IFN-γ-producing pathogenic CD4+ T cells to effector sites. IFN-α/β upregulated the expression of the cognate ligands CXCL9, CXCL10, and CXCL11, causing ligand-mediated downregulation of CXCR3 expression and effector T cell retention in the spleen. Accordingly, type I IFN did not alter EAU progression in CXCR3-/- mice. In uveitis patients, disease exacerbations correlated with reduced serum IFN-α concentrations. IFN-α/β reduced CXCR3 expression and migration by human effector T cells, and these parameters were associated with the therapeutic efficacy of IFN-α in uveitis patients. Our findings provide insight into the molecular basis of type I IFN therapy for CNS autoimmune diseases and identify CXCR3 as a biomarker for effective type I IFN immunotherapy.

Immunopathogenesis of Behçet Disease

BACKGROUND

Behçet's Disease (BD, OMIM 109650) is a chronic relapsing inflammatory disease of unknown etiology with unpredictable exacerbations and remissions. First described in 1937 by the Turkish dermatologist HulusiBehçet, as a trisympton complex (oral and genital ulcers and uveitis), it is now recognized as a multisystemic disease. The syndrome can manifest in diverse ways and can involve nearly every organ system. Several studies have implicated T cells and monocytes in the pathogenesis of BD especially when these cells are stimulated by heat shock proteins and streptococcal antigen. This article presents a review of the relevant published literature about the immunopathogenesis of BD.

RESULT

The authors used MeSH terms "Behçet's disease" with "pathophysiology," "pathogenesis," "genetic", "epigenetic", "immunogenetic" or "immune response" to search the PubMed database. All the relevant studies identified were included.

Behçet disease: New aspects

Behçet disease is currently considered an "autoinflammatory disease" triggered by infection and environmental factors in genetically predisposed individuals. Although the disease is characterized by recurrent oral and genital aphthous ulcers and ocular involvement, it can affect multiple organ systems. Complex aphthosis is characterized by recurrent oral and/or genital aphthous ulcers. It is important to evaluate the patient with complex aphthosis for Behçet disease and related systemic disorders. We discuss the etiopathogenesis, clinical features, diagnostic criteria, and treatment approaches for complex aphthosis and Behçet disease in light of the current literature.

Behcet’s disease: from heat shock proteins to infections

Background: Behcet’s disease (BD) is a chronic, inflammatory multisystemic condition of unknown etiology. Although the cause of BD is not clear, it is believed to be the result of an autoimmune process triggered by an infectious or environmental agent (possibly local to a geographic region) in a genetically predisposed individual.

Objective: To detail current knowledge of the role of microorganisms in the pathogenesis of BD and review the infectious etiology of this disease.

Methods: The review based on publication in SCOPUS, Science direct, and PubMed.

Results: A microbial infection has been implicated in the development of the disease to explain the strong inflammatory reactions observed, the activation of monocytes and macrophages, and the induction of proinflammatory cytokines and chemokines detected. Common factors linking some of the possible pathogenetic agents are extrinsically induced tissue stress or heat shock proteins, which react with host tissues and elicit significant T-helper type 1 cell responses.

Conclusion: Based on collected data, we conclude that the microorganisms discussed seem to participate and, at least in part, act as triggers during the course of BD. By clarifying the microbial associations of BD and finding its etiology, particularly the causative antigens leading to BD, it would be easier to suggest more effective treatment and preventive strategies for this disease.

Cytokines Modulate the "Immune-Metabolism" Interactions during Behçet Disease: Effect on Arginine Metabolism

Aim and Methods. In this study, we evaluated NOS and arginase activities and their regulation during Behçet disease, a systemic chronic inflammatory disorder with uncertain etiology. The peripheral blood mononuclear cells of 36 patients and 15 control samples (PBMC) were cultured in either RPMI 1640, MEM, or DMEM complemented with 10% of FBS and antibiotics. Cultures were performed with or without the control or patients plasma. Subsequent treatment contained anticytokines (IL-6, TGF-β), a mitogenic effector (PHA), or NOS modulators (L-NMMA, BH4). Culture supernatants were harvested after 24 h of incubation. NO and urea measurements were, respectively, performed by modified Griess and Berthelot methods. Results. Higher urea levels were found in patients' plasma compared to the control's (P < 0.05). NOS modulators induced inverted production profiles for NO and urea (P < 0.05). Their results differed depending on the clinical findings (P < 0.05). It was also found that cytokine neutralization induced different response profiles in patients as opposed to control cultures (P < 0.05). Conclusion. Our results suggest that arginases can compete with NOS2 for L-arginine during Behçet disease. Both enzymes are regulated by environmental cytokines and substrate availability. Furthermore, it seems that NOS/arginase balance is dependent on clinical expression.

Long-term efficacy of infliximab on background vascular leakage in patients with Behçet's disease

PURPOSE

To evaluate the effect of infliximab over the initial 4 years of treatment on inflammatory ocular attacks and background retinal/disc vascular leakage in patients with refractory uveoretinitis associated with Behçet's disease.

METHODS

Clinical records of nine patients were retrospectively reviewed. The main outcomes analyzed were frequency of ocular inflammatory attacks, background retinal and disc vascular leakage as assessed by fluorescein angiography during periods of clinical quiescence, best-corrected visual acuity, and adverse effects.

RESULTS

The median follow-up on infliximab was 50 months (range 48-58 months). Mean frequency of attacks decreased significantly in years 1, 2, 3, and 4 compared with the baseline 1-year period before infliximab use. Mean background retinal and disc vascular leakage scores also decreased significantly at the end of each 1-year period compared with baseline. Visual acuity improved or was unchanged at the end of 4 years in 17 of 18 eyes. No serious adverse effects were observed.

CONCLUSION

Infliximab reduced the mean frequency of ocular attacks and mean background retinal/disc vascular leakage in a long-term sustained manner over 4 years of treatment in Behçet's disease patients.

Differential diagnosis of behçet uveitis

The diagnosis of Behçet disease is clinical and based on the presence of characteristic ocular and systemic inflammatory manifestations. Patients may present with anterior, posterior, or panuveitis in one or both eyes. The differential diagnosis includes a variety of infectious and noninfectious causes of acute nongranulomatous anterior uveitis, intermediate uveitis, occlusive retinal vasculitis, focal or multifocal retinitis, and necrotizing retinitis. A course characterized by sudden onset with improvement followed by recurrence of inflammatory signs is most typical for Behçet uveitis.

Current approach in the diagnosis and management of panuveitis

Panuveitis is a generalized inflammation of not only the whole of the uveal tract but also involves the retina and vitreous humor. It differs from other anatomical sites of inflammation in terms of causes as well as distribution. The common causes of panuveitis in our population are tuberculosis, Vogt-Koyanagi-Harada syndrome, sympathetic ophthalmia, Behcet's disease and sarcoidosis. A large number of cases still remain idiopathic. A stepwise approach is essential while evaluating these patients to be able to identify and treat the disease timely and correctly. Ancillary tests can be appropriately applied once the anatomic site of inflammation is identified. An exhaustive approach comprising a full battery of tests is obsolete. Only specific tailored investigations are ordered as suggested by the preliminary clinical and ocular examination. The mainstay of the treatment of uveitis is corticosteroids. Immunosuppressive agents are administered if the inflammation is not adequately controlled with corticosteroids. One of the recent breakthroughs in the treatment of refractory uveitis includes the introduction of immunomodulating drugs: Tumor necrosis factor-alpha antagonist and Interferon-alpha. Vitrectomy has been used in uveitis for over a few decades for diagnostic and therapeutic purposes. When compared to other anatomical sites of inflammation, panuveitis has poor visual outcome due to more widespread inflammation. The side-effects of the chronic treatment that these patients receive cannot be overlooked and should be specifically monitored under the supervision of an internist with special interest in inflammatory diseases.

Epidemiology and clinical characteristics of Behçet's disease in the US: a population-based study

OBJECTIVE

Behçet's disease (BD) is a rare, multisystem inflammatory disorder of unknown cause. Although well-documented in Eastern populations, epidemiologic data is scarce in North American countries. Here we describe the incidence and prevalence of BD in Olmsted County, Minnesota over 45 years.

METHODS

We identified an incidence cohort of subjects age >/=18 years who had a clinical diagnosis of and/or fulfilled the International Study Group (ISG) criteria for BD from January 1, 1960 to January 1, 2005. Age- and sex-specific incidence and prevalence were estimated and age- and sex-adjusted to the 2000 US total population.

RESULTS

The study population was comprised of 13 subjects with BD; 11 fulfilled ISG criteria between 1960 and 2005. Mean +/- SD age was 31 +/- 9 years, and 69% were white. Point prevalence in 2000 was 5.2 per 100,000 population (95% confidence interval [95% CI] 0.64-9.84). The overall annual age- and sex-adjusted incidence of BD was 0.38 per 100,000 population (95% CI 0.17-0.59), with a higher incidence in women (0.51 per 100,000; 95% CI 0.17-0.84) than in men (0.26 per 100,000; 95% CI 0.004-0.52). Dermatologic lesions included oral ulcers (100%), genital ulcers (62%), erythema nodosum (46%), and papulopustular lesions (54%). Ocular lesions, vascular complications, and central nervous system involvement were present in 8, 3, and 3 subjects, respectively.

CONCLUSION

Our study shows an overall incidence of 0.38 per 100,000 population, which is comparable with other Western populations. The prevalence of 5.2 per 100,000 population is similar to estimates reported in Western countries, but lower than that in countries along the Silk Road.

Alterations of aqueous flare and cells detected by laser flare-cell photometry in patients with Behcet's disease

PURPOSE

To quantitatively evaluate aqueous flare and cells in patients with Behcet's disease.

METHODS

This study included 30 Behcet's patients (52 eyes) with active uveitis. The patients were treated with immunosuppressive agents. Aqueous flare and cells were quantified using the laser flare-cell photometry before treatment and 1 and 2 months after treatment.

RESULT

Before treatment, mean aqueous flare (ph/ms) in Behcet's eyes was 25.7 ± 20.5. After treatment, flare values were significantly reduced after 1 and 2 months compared with those before treatment. No significant difference was found between flare values after 1 and 2 months. Before treatment, mean cell counts (cells/0.5 mm(3)) in Behcet's eyes were 23.2 ± 29.4. After treatment, cell counts were also significantly reduced after 1 and 2 months compared with those before treatment. Cell counts were further significantly reduced from 1 to 2 months.

CONCLUSION

Both aqueous flare and cells were significantly increased in Behcet's patients with active uveitis and improved after a two-month treatment. Breakdown of the blood-aqueous barrier lasts longer than aqueous cells in these patients.

Ocular features of Behcet's disease: an international collaborative study

OBJECTIVE

To investigate the clinical features of ocular lesions in Behçet's disease in different countries.

METHODS

A descriptive questionnaire survey was performed.

RESULTS

25 eye centres in 14 countries returned questionnaires on prevalent cases in 2006. Clinical data were analysed on 1,465 patients with ocular lesions. Recurrent oral aphthous ulcers were reported in 94.5%, skin lesions in 69.5% and genital ulcers in 61.4%. Most of the patients had bilateral and recurrent intraocular inflammation. Poor visual acuity was seen in 18.9% in women, but 24.8% in men (p<0.01). Panuveitis was seen more in men than in women (p<0.01). 23% of the patients had visual acuity equal to or worse than 20/200 at the final visit. The patients with poor vision were more frequently in India, Iran and Japan than in other countries (p<0.01).

CONCLUSIONS

We report the largest contemporary international case series of patients with ocular involvement in Behçet's disease. Panuveitis was significantly more frequent in men than women, and men tended to have a worse visual prognosis. There were some differences in the clinical pattern of Behçet's disease in different countries. Despite modern treatment, the disease still carries a poor visual prognosis with one-quarter of the patients blind.