Behçet's disease: review with emphasis on dermatological aspects

Abstract

Behçet's disease is a systemic vasculitis characterized by attacks of acute inflammation, which can affect almost every vascularized area of the body. There is a close correlation between the geographical distribution of HLA-B51 and its prevalence. In the etiopathogenesis there are indications of genetic susceptibility associated with environmental influence. Among the involved genes are those that encompass innate and adaptive immunities. Polymorphisms and epistatic interactions in several genes are described, as well as the presence of imbalance lineage between HLA-B51 and A (MICA). Herpes simplex and Streptococcus sanguinis may be important extrinsic factors. An increase of Th1 response and of IL-21 is observed. The production of IL-21 is positively related to Th17 cells and negatively to T-regs. The mucocutaneous manifestations are Behcet´s disease markers, and their earlier onset indicates a worse prognosis. Recurrent oral ulcers have varied sizes and arrangements, genital ulcers are recurrent, leaving scars, skin lesions are multivaried, and pathergy, although not so frequent, is important for the diagnosis. There are numerous attempts to validate indexes that can evaluate the disease activity and among them the Mucocutaneous Activity Index. This is a specific score that can help with therapeutic decisions and to reduce morbidity, but still lacks validation. The clinical manifestations of other organs are described as well as treatment options.

T helper 17 cell/regulatory T-cell imbalance in hidradenitis suppurativa/acne inversa: the link to hair follicle dissection, obesity, smoking and autoimmune comorbidities

“…IL‐17 plays a role in the pathogenesis of spondylarthritis . In Behçet disease, which is reported to have a higher prevalence in patients with HS, an increased Th17/Treg ratio has also been observed …”

“…100 Another common association is seronegative arthritis, particularly spondylarthritis. 99,100,[105][106][107][108][109][110][111][112][113][114][115][116][117] The proper balance of intestinal Tregs and Th17 cells is important for intestinal homeostasis. 108,109 Increased Th17 cells and decreased Tregs have been reported in Crohn disease.…”

“…112 In Behc ßet disease, which is reported to have a higher prevalence in patients with HS, 38,39,99 an increased Th17/Treg ratio has also been observed. 113 Population-based observational studies and case-control studies reported an increased association of HS with depression. 105,[114][115][116][117] There is an emerging tendency towards autoimmunity occurring in major depressive disorders exhibiting a deviated Th17/Treg axis with increased Th17 cell differentiation.…”

Macrophage Migration Inhibitory Factor –173GC Variant Might Increase the Risk of Behçet’s Disease

“…This disease is also subject to background genetic susceptibility [1]. Four factors imply a genetic impact on BD susceptibility: geographical distribution, familial aggregation, association with HLA-B51 class I antigen, and polymorphisms in genes that modulate immune responses [2]. Some studies in different ethnic groups have shown that there is a correlation between HLA-B51 and BD, and this correlation with HLA-B51 is believed to be the strongest genetic susceptibility factor for BD, and it is assumed to be involved in neutrophil activation [1].…”

“…Cytokines play crucial roles in the pathogenesis of BD, due to their impact and regulatory functions in immune and inflammatory reactions [3]. Overexpression of proinflammatory cytokines, mainly Th1 and Th17 from several cellular sources, seems to account for the increased inflammatory response in BD and may be linked with genetic susceptibility [2]. …”