The seroprevalence of varicella zoster antibodies in Behçet's and other skin diseases

Infectious agents and pathogenesis of Behçet's disease: An extensive review

Behçet's disease (BD) is a multisystemic chronic vasculitis. Sustained and enhanced immune responses were reportedly associated with active BD. Although genetic polymorphisms increase development risk, genetic factors alone cannot account for BD development, suggesting the involvement of exogenous factors. Also, how various infectious agents promote BD in high-risk populations is not fully understood. In this review, we summarized the current findings on the associations of infectious agents with BD pathogenesis. The review also highlights the potential microbial risk factors and their pathogenic role in BD progression. Interactions between genetic and infectious risk factors was also discussed. Furthermore, evidence implied that after the eradication of infectious agents, BD symptoms and recurrence decreased, thus highlighting that combined use of antibiotics may be an effective therapy for BD. Finally, we summarized the main limitation of the current related studies, providing valuable insights and a basis for future studies on BD pathogenic factors.

The role of bacteria and viruses in Behçet syndrome: Should we move towards new paradigms?

The etiological complexity of Behçet syndrome (BS), an immune-mediated rare form of vasculitis characterized by multi-organ involvement, is still elusive due to an incomplete understanding of the synergy between genetic susceptibility, environmental triggers, and an abnormal immune response. Long-standing theories regarding the origins of BS include the involvement of infectious organisms supporting an aberrant immunological response through different mechanisms, including molecular mimicry. Additionally, it has been demonstrated that the BS phenotypes are linked to oral and gut microbiome dysbiosis, which is a dynamic reservoir of millions of microbes containing proteins and metabolites that can mimic the autoantigens. Infections, including viral pathogens, could potentially trigger the inflammation and symptoms of BS. In this review, we aim to describe the available evidence on the cross-talk between BS and infections in order to discuss potential clinical implications and possible therapeutic targets.

Behçet's Disease with Severe Autonomic Disorders Developing after Herpes Zoster

A 58-year-old Japanese woman with herpes zoster developed Behçet's disease (BD) with symptoms including orthostatic intolerance as an autonomic disorder. Multiple immune-suppressive therapies and a β-blocker successfully controlled both the disease activity of BD and the autonomic disorders. A cytokine multiplex analysis of her serum revealed the elevation of proinflammatory cytokines [interleukin (IL)-1, IL-6, IL-12, tumor necrosis factor alfa (TNFα), and interferon gamma (IFN-γ)] and a low IL-10 concentration. IL-10 production is reported to be important for defense against herpes zoster virus (VZV). Insufficient IL-10 production is reported in BD. The reactivation of VZV with this cytokine profile suggests that BD will develop with various symptoms, including severe autonomic disorders.

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.

[Epidemiology of Behçet's disease]

With more than 30 published prevalence estimates for Behçet's disease (BD), covering many different regions worldwide, the prevalence of BD is quite well described. Even though the interpretation of these data is complicated by between-study differences in methodology, which may substantially influence the results, these data suggest large geographic variations in frequency of BD, with prevalence rates of 20-420/100,000 inhabitants for Turkey, 2.1-19.5 for other Asian countries, 1.5-15.9 for southern Europe and 0.3-4.9 for northern Europe. Additional epidemiological studies or case series from North and South America, the Caribbean Islands, and individuals of sub-Saharan ancestry further suggest that the geographic distribution of BD is much wider than the boundaries of the ancient Silk Road. The few available incidence rates prevent from making strong inferences as to whether the frequency of BD has changed over time. Recent population-based studies of immigrants or migrant populations consistently indicate that migrants from areas of high BD prevalence remain at high risk for BD, which may even be close to the prevalence observed in their countries of origin. Genetic factors, which are not detailed in this review, seem to play a preponderant role in BD development, although they cannot explain the wide between-country disparities in BD prevalence. However, environmental risk factors, including infectious and non-infectious causes, remain poorly investigated and have not yet produced solid hints.

Potential Infectious Etiology of Behçet's Disease

Behçet's disease is a multisystem inflammatory disorder characterized by recurrent oral aphthous ulcers, genital ulcers, uveitis, and skin lesions. The cause of Behçet's disease remains unknown, but epidemiologic findings suggest that an autoimmune process is triggered by an environmental agent in a genetically predisposed individual. An infectious agent could operate through molecular mimicry, and subsequently the disease could be perpetuated by an abnormal immune response to an autoantigen in the absence of ongoing infection. Potentia bacterial are Saccharomyces cerevisiae, mycobacteria, Borrelia burgdorferi, Helicobacter pylori, Escherichia coli, Staphylococcus aureus, and Mycoplasma fermentans, but the most commonly investigated microorganism is Streptococcus sanguinis. The relationship between streptococcal infections and Behçet's disease is suggested by clinical observations that an unhygienic oral condition is frequently noted in the oral cavity of Behçet's disease patients. Several viral agents, including herpes simplex virus-1, hepatitis C virus, parvovirus B19, cytomegalovirus, Epstein-Barr virus and varicella zoster virus, may also have some role.

New insights into the pathogenesis of Behçet's disease

Behçet's disease (BD) is a recurrent systemic inflammatory disorder of unknown origin characterized by oral and genital mucous ulcer, uveitis, and skin lesions. Involvement of large vessels, central nervous system (CNS), gastrointestinal tract and thrombotic events are less frequent but can be life threatening. The aim of this review is to provide new insights into the pathogenesis of BD. Over the past year substantial advances have been done in the understanding of the genetic [1,2] and immunology [3] of BD. BD is at the crossroad between autoimmune and autoinflammatory syndromes. In common with autoimmune diseases BD shares class I MHC association. However, in contrast to autoimmune disorders, BD has clinical features that seem to be mostly autoinflammatory. The pathogenesis of BD is still unknown, but major determinants of the genetic and immune system abnormalities have been reported recently. Triggering infectious factors are supposed to participate in the outbreak of BD in genetically predisposed patients. Two recent large genome-wide association study (GWAS) conducted in Turkey and Japan reported association between single nucleotide polymorphism (SNP) of interleukin (IL)-10 and IL-23R/IL-12RB2 genes and BD. New insights into the perturbations of T cell homeostasis of BD recently emerged. We have recently demonstrated the promotion of Th17 responses and the suppression of regulatory T cells (Tregs) that were driven by interleukin (IL)-21 production and that correlates with BD activity. Inflammatory cells within BD inflammatory lesions included mostly neutrophils, Th1 and Th17 cells, and cytotoxic CD8+ and γδ T cells. Altogether, the recent progresses in the knowledge of BD pathogenesis pave the way for innovative therapy.

Physiopathologie de la maladie de Behçet

SUBJECT

Pathophysiology of Behçet's disease (BD) is complex. Recent experimental data shed new light on the mechanisms leading to organ lesions.

MAIN ISSUES

Neutrophils and cytotoxic lymphocytes are now recognized as key effector cells in BD. Genetic susceptibility, environmental factors (virus and/or bacterial infections), inflammatory response abnormalities (heat shock proteins, dysregulated NO production) and abnormal immune response play also a major role in BD pathogeny.

PERSPECTIVES

Better understanding of the BD pathophysiology will allow the development of new therapies more specific of BD.

Behçet syndrome

PURPOSE OF REVIEW

Interest in Behçet syndrome (BS), although the condition is rare in many parts of the world, is increasing as judged by the growing number of related publications and scientific meetings.

RECENT FINDINGS

Recent work reconfirmed the following without further insight into their meaning in pathogenesis: males have a more severe course; one third of the patients have a thrombophilia; papulopustular lesions and arthritis go together; gammadelta T are increased; and HLA B51 is still the main genetic association. Presence of increased levels of antibodies to Saccharomyces cerevisiae and the proposal of alpha-enolase as the target antigen of antiendothelial cell antibodies, known to be present also in BS, are observations that might help in delineating the unknown pathogenesis. For management, preliminary yet promising experience with the use of anti-tumor necrosis factor agents is being reported. SUMMARY When compared with 2 decades ago, we know considerably more and can do more about BS.