Acometimento vascular na doença de Behçet: o processo imunopatológico / Vascular involvement in Behçet's disease: the immunopathological process

Resumo A doença de Behçet constitui uma forma rara de vasculite sistêmica, que acomete de pequenos a grandes vasos. É caracterizada por manifestações mucocutâneas, pulmonares, cardiovasculares, gastrointestinais e neurológicas. Sua apresentação clínica é bastante ampla, variando de casos mais brandos a casos graves, com acometimento multissistêmico, caracteristicamente com exacerbações e remissões. Suas causas ainda são desconhecidas; entretanto, há evidências genéticas, ambientais e imunológicas, como a associação com o alelo HLA-B51. Todas essas, em conjunto, apontam para um processo imunopatológico anormal, com ativação de células da imunidade inata e adaptativa, como as células natural killer, neutrófilos e células T, que geram padrões de respostas e citocinas específicos capazes de gerar mediadores que podem lesionar e inflamar o sistema vascular, resultando em oclusões venosas, arteriais e/ou formação de aneurismas.

Abstract Behçet's disease is a rare form of systemic vasculitis that affects small to large vessels. It is characterized by mucocutaneous, pulmonary, cardiovascular, gastrointestinal, and neurological manifestations. Its clinical presentation is quite wide, ranging from milder cases to severe cases, with multisystemic involvement, characteristically with exacerbations and remissions. Its etiopathogenesis is still unclear, although there is evidence of genetic, environmental, and immunological factors, such as the association with the HLA-B51 allele. In conjunction, all of these point to an abnormal immunopathological process, with activation of cells of innate and adaptive immunity, such as NK cells, neutrophils, and T cells, which generate specific response patterns and cytokines capable of generating mediators that can damage and inflame blood vessels, resulting in venous and arterial occlusions and/or aneurysm formation.

TIM-3 genetic variants and risk of Behçet disease in the Iranian population

Abstract: Background: Behçet disease is a prototypical systemic autoimmune disease, caused by a complex interplay between environmental and genetic factors. The transmembrane immunoglobulin and mucin domain-3 (TIM-3) is a distinct member of the TIM family that is preferentially expressed on Th1 cells and plays a role in Th1-mediated autoimmune or inflammatory diseases, such as Behçet disease. Objective: The aim of this study was to test the potential association between TIM-3 gene polymorphisms and Behçet disease. Methods: Two single-nucleotide polymorphisms of TIM-3 (rs9313439 and rs10515746) were genotyped in 212 patients with Behçet disease and 200 healthy controls. Typing of the polymorphisms was performed using multiplex PCR amplification. Results: There were no significant differences in allele and genotype frequencies between the Behçet disease patients and controls who were successfully genotyped. Similar results were also found after stratification by gender, age, or clinical features. Study limitations: Lack of studies on various racial or ethnic groups and small sample size. Conclusion: This study failed to demonstrate any association between the tested TIM-3 polymorphisms and Behçet disease.

Targeted resequencing of candidate genes reveals novel variants associated with severe Behcet's uveitis

Behcet's disease (BD) is a chronic systemic inflammatory disorder characterized by four major manifestations: recurrent uveitis, oral and genital ulcers and skin lesions. To identify some pathogenic variants associated with severe Behcet's uveitis, we used targeted and massively parallel sequencing methods to explore the genetic diversity of target regions. A solution-based target enrichment kit was designed to capture whole-exonic regions of 132 candidate genes. Using a multiplexing strategy, 32 samples from patients with a severe type of Behcet's uveitis were sequenced with a Genome Analyzer IIx. We compared the frequency of each variant with that of 59 normal Korean controls, and selected five rare and eight common single-nucleotide variants as the candidates for a replication study. The selected variants were genotyped in 61 cases and 320 controls and, as a result, two rare and seven common variants showed significant associations with severe Behcet's uveitis (P<0.05). Some of these, including rs199955684 in KIR3DL3, rs1801133 in MTHFR, rs1051790 in MICA and rs1051456 in KIR2DL4, were predicted to be damaging by either the PolyPhen-2 or SIFT prediction program. Variants on FCGR3A (rs396991) and ICAM1 (rs5498) have been previously reported as susceptibility loci of this disease, and those on IFNAR1, MTFHR and MICA also replicated the previous reports at the gene level. The KIR3DL3 and KIR2DL4 genes are novel susceptibility genes that have not been reported in association with BD. In conclusion, this study showed that target enrichment and next-generation sequencing technologies can provide valuable information on the genetic predisposition for Behcet's uveitis.

Mediterranean fever gene mutations in greek patients with Behcet's disease / Mutacionesen el gen de la fiebre mediterránea en pacientes griegos con la enfermedadde Behçet

OBJECTIVE: It is known that clinical similarities between Behcet's disease and Familial Mediterranean Fever have led to the hypothesis of a common pathogenesis. Familial Mediterranean Fever is caused by MEFV gene mutations coding for pyrin. Therefore, we examined whether these pyrin mutations are also associated with Behcet's disease. METHODS: Molecular testing for pyrin mutations was performed in 96 unrelated Greek patients with an established diagnosis of Behcet's disease. The results were compared with an analysis for pyrin mutations in 140 unrelated healthy Greek controls. RESULTS:We found no pyrin mutations among the Behcet cases tested; this result is comparable with the control group. CONCLUSIONS: Pyrin gene mutations in Greek patients with Behcet's disease are not more common than those in the general population. This finding is not in agreement with the findings in other populations. It is suggested that screening for pyrin mutations not be included in the evaluation of Greeks suspected to have Behcet's disease.

OBJETIVO:Se sabe que las similitudes clínicas entre la enfermedad de Behçet y la fiebre mediterránea familiar han llevado a la hipótesis de una patogénesis común. La fiebre mediterránea familiar es causada por mutaciones en el gen MEFV que codifica la pirina. Por lo tanto, examinamos si estas mutaciones de la pirina se hallan también asociadas con la enfermedad de Behçet. MÉTODOS: La prueba molecular para la detección de las mutaciones de la pirina se realizó en 96 pacientes griegos no relacionados, y diagnosticados con la enfermedad de Behçet. Los resultados se compararon con un análisis de las mutaciones de la pirina en 140 controles formados por individuos griegos saludables. RESULTADOS: No se encontraron mutaciones de pirina entre los casos de Behçet sometidos a prueba. Este resultado es comparable con el grupo control. CONCLUSIONES: Las mutaciones del gen de la pirina en los pacientes griegos con la enfermedad de Behçet no son más comunes que las de la población general. Este hallazgo no concuerda con los hallazgos en otras poblaciones. Se sugiere que el tamizaje para la detección de las mutaciones de pirina no se incluya en la evaluación de pacientes griegos sospechosos de padecer la enfermedad de Behçet.

Extracellular High-Mobility Group Box 1 is Increased in Patients with Behcet's Disease with Intestinal Involvement

High-mobility group box 1 (HMGB1) protein has been demonstrated to play an important role in chronic inflammatory diseases including rheumatoid arthritis, and systemic lupus erythematosus. This study investigated the association between extracellular HMGB1 expression and disease activity, and clinical features of Behcet's disease (BD). Extracellular HMGB1 expression in the sera of 42 BD patients was measured and was compared to that of 22 age- and sex-matched healthy controls. HMGB1 expression was significantly increased in BD patients compared to healthy controls (78.70 +/- 20.22 vs 10.79 +/- 1.90 ng/mL, P = 0.002). In addition, HMGB1 expression was significantly elevated in BD patients with intestinal involvement compared to those without (179.61 +/- 67.95 vs 61.89 +/- 19.81 ng/mL, P = 0.04). No significant association was observed between HMGB1 concentration and other clinical manifestations, or disease activity. It is suggested that extracellular HMGB1 may play an important role in the pathogenesis of BD.

Behcet's disease: an assessment of cutaneous, ocular and articular characteristics in the south of Jordan

To determine the spectrum and the frequency of skin, eye and joint manifestation in patients with Behcet's Disease in the southern parts of Jordan. Twenty three patients diagnosed to have Behcet's Disease were included in the study. The diagnosis was based on the criteria proposed by the International Study Group of Behcet's Disease. In order to detect the various cutaneous, ocular and articular manifestations of the disease, all patients were thoroughly evaluated by a dermatologist, an ophthalmologist, and a rheumatologist. Pathergy test was performed for all patients. Fifteen patients were males [65.1%] and eight were females [34.8%]. The mean age was 32.5 years Oral ulcers were detected in all the patients and genital ulcers were found in 56.5% of the patients. Other skin lesions were detected in 56.5% of the patients. Ocular lesions occurred in 60.8% of the patients. Joint involvement was found in 43.4% of the patients. The pattern of cutaneous, ophthalmic and articular manifestation in our group of patients was different from patterns reported in countries with different races and similar to patterns in neighboring countries. The results may reflect the effect of differences in both the genetic background and environmental factors among different countries

Familial Behcet's disease.

There are very few reports of Behetaet's disease from India. Familial aggregation of Behetaet's disease has been reported with restricted geographical distribution. We report here familial Behcet's disease from India in two brothers aged 30 and 32 years. Both patients had recurrent oral and genital ulcers for approximately five years. They also had arthralgias on and off along with fever. Pathergy test was positive in both cases. Their younger brother and a sister had recurrent oral aphthous ulcers.

Association of TNFA Promoter Region Haplotype in Behcet's Disease

Although the etiology of Behcet's Disease (BD; MIM 109650) remains to be clearly elucidated, levels of tumor necrosis factor alpha (TNF-alpha) have been reported to be significantly elevated in BD patients, and TNF-alpha blockers have been demonstrated to exhibit some degree of therapeutic efficacy for a certain subset of BD sufferers. In this study, we have conducted an analysis of the TNFA haplotypes in the promoter response element that affect the binding affinity of specific transcription factors, in order to characterize their association with the clinical features of BD. Six polymorphisms in the promoter region of TNFA were genotyped in 254 BD patients and 344 control subjects, via the PCR-RFLP technique. TNFA -1031*C, -863*A and -308*G alleles were associated with an increased risk of BD (p=0.030, OR=1.4; p=0.008, OR=1.5; p=0.010, OR=1.8, respectively). The sole TNFA haplotype -1031C-863A-857C-376G-308G-238G, was associated with a 1.6 fold increase in the risk of BD, whereas the TNFA haplotype -1031T-863C-857C-376G-308A-238G was associated with a 0.6 decreased risk of BD. The TNFA -1031*C, -863*A, -857*C and -308*G alleles were significantly associated with BD. The findings of this study, collectively, indicate that TNFA haplotypes in the promoter response elements may exert significant influence on susceptibility to BD.

Enfermedad de Behçet: presentación de dos casos y revisión de la literatura / Behcet's disease: presentation of two cases and literature review

La enfermedad de Behçet es un trastorno inflamatorio multisistémico crónico caracterizado por úlceras genitales y orales recurrentes, uveítis y lesiones en piel, siendo además frecuente el compromiso del tracto gastrointestinal (TGI), sistema nervioso central (SNC) y de grandes vasos. Se presenta el caso de dos pacientes, el primero de ellos es el de una mujer de 30 años con un cuadro clínico caracterizado por una panuveítis severa, recurrente, de muy difícil manejo, asociada a aftas orales y genitales, la cual requirió múltiples tratamientos con agentes inmunosupresores, el segundo caso es el de una mujer de 35 años, quien consultó por presentar un cuadro de quince días de evolución de úlceras en mucosa oral y genital recurrentes, dolorosas, nódulos eritema-violáceos en ambos miembros inferiores y síntomas sistémicos. Al examen oftalmológico se observa una uveítis no granulomatosa leve y la biopsia de piel mostró vasculitis leucocitoclástica. Con base en los anteriores hallazgos se estableció el diagnóstico de enfermedad de Behçet, teniendo en cuenta los criterios clínicos, se inicia tratamiento con prednisona 1mg/kg/día con mejoría de su cuadro

Behcet's Disease: The First Mongolian Case in Literature Showing HLA B51, MICA Gene Type *5/*6

Behcet's disease is a chronic multi-systemic disease of unknown origin that includes mucocutaneous, ocular, cardiac, vascular, renal, gastrointestinal, neurologic and cutaneous involvement. The disease is spread throughout the world, but it is most prevalent in the eastern Mediterranean region-along the Silk Road-, and in Japan, China, and Korea. Recently, we treated a Mongolian patient who had complete-type Behcet's disease. As far as we know, this case is the first report of a Mongolian with Behcet's disease in the English literature. HLA typing in this patient revealed A2, A24; B51, B35; Cw4, Cw7; DR9, DR11. Study of the MICA genetype showed *5, *6 positive. Our data provided adequate evidence, from an epidemiological aspect, to support the belief that Behcet's disease is most prevalent along the old Silk Road.

Association of MICA Polymorphism with HLA-B51 and Disease Severity in Korean Patients with Behcet's Disease

The HLA-B51 allele is known to be associated with Behcet's disease (BD) in many ethnic group. However, it has not yet been clarified whether the HLA-B51 gene itself is the pathogenic gene related to BD or whether it is some other gene in linkage disequlibrium with HLA-B51. Recently, the Triplet repeat (GCT/AGC) polymorphism in transmembrane region of the MHC class I chain-related A (MICA) gene was identified. To investigate the association of MICA with BD, we studied the MICA polymorphism in 108 Korean BD patients and 204 healthy controls in relation to the presence of HLA-B51 and clinical manifestations. The triplet repeat polymorphism was determined by polymerase chain reaction (PCR)-denaturing polyacrylamide gel electrophoresis (PAGE). The phenotype frequency of the MICA*A6 allele (relative risk, RR=2.15, p=0.002) and HLA-B51(RR=1.87, p=0.022) were significantly increased in the Korean patients with BD. A strong linkage disequilibrium was observed between the MICA*A6 and HLA-B51 in both the patients with BD and control subjects. Stratification analysis showed that MICA*A6 homozygosity was strongly associated with BD in the HLA-B51-negative population, and HLA-B51 was also associated with MICA*A6-negative population. In conclusion, MICA*A6 rather than HLA-B51 was strongly associated with Korean patients with BD, and the MICA*A6 allele is a useful susceptibility marker of BD, especially in the HLA-B5-negative

Doença de Behçet: aspectos etiopatogênicos / Behçet's disease: etiopathogenic aspects

A doença de Behçet (DB) é uma vasculite sistêmica, recorrente e crônica com manifestações que incluem úlceras orogenitais, uveíte, sinovite, tromboflebite e sintomas envolvendo o SNC, trato gastrointestinal e pulmão. Embora a patogênese da DB não seja totalmente esclarecida, existem estudos apontando para possível participação de agentes infecciosos (virais e bacterianos), fatores genéticos e desregulação imunológica. Dentre os agentes infecciosos, alguns trabalhos sugerem o possível papel do Streptococcus sanguis (SS). Os pacientes com DB mostram aumento da frequência de ss na flora oral, comparada com controles, bem como de anticorpos séricos contra certos sorotipos de ss. No soro de alguns pacientes foi possível observar aumento de anticorpos específicos contra HSP-65 (Heat Shock Protein) de Mycobacterium tuberculosis, que são capazes de produzir reação cruzada com certos sorotipos de ss. Estudos recentes demonstraram que o HLA-B, até então estabelecido como associado à DB, poderia não ser o lócus primário responsável pela predisposição à doença, sendo sugerida a participação de outros genes localizados próximos ao lócus HLA-B, incluindo os genes MICA, PERB, e NOB. Em conclusão, uma proposta etiopatogênica é de que um antígeno particular, provavelmente de origem bacteriana, seja apresentado por macrófagos e reconhecido por células T CD4+ no contexto do MHC classe II. Linfócitos T ativados produziriam citocinas como IL-2, IFN-y, TNF-B e induziriam a proliferação e diferenciação de células B específicas. Macrófagos ativados por IFN-Y são capazes de liberar citocinas inflamatórias como TNF-alfa, IL-1, e IL-8. Fator de necrose tumoral (TNF) e IL-1 poderiam induzir a expressão de moléculas de adesão em células endoteliais, enquanto a IL-8 estaria envolvida na quimiotaxia e ativação de neutrófilos no sítio da reação inflamatória. Esses eventos seriam responsáveis pela passagem de polimorfonucleares neutrófilos e linfócitos T ativados através do endotélio na área inflamada

Behcet's disease associated with myelodysplastic syndrome: a case report

A rare case of Behcet's disease associated with myelodysplastic syndrome (MDS) is described. A 50-year-old Korean female suffering recurrent oral ulcer, genital ulcer, fatigue, arthralgia in both knees and fever was diagnosed as Behcet's disease. The findings of bone marrow aspirates were consistent with refractory anemia, a subtype of myelodysplastic syndrome. Chromosomal analysis of bone marrow cells revealed 46,XX,-8,-20,+der(8)t(8;20)(p23;p10),+der(8) t(8;20)(p23;q10)[30]. The chromosomal changes found in this patient were different from those of previous reports, which mostly revealed trisomy 8. If anemia, low reticulocyte count and dyspoietic cells are sustained in Behcet's disease, physicians should be alert to the possibility of MDS with aberration in chromosome 8 and perform a bone marrow study for the proper diagnosis and treatment of the disease. We presented a case of Behcet's disease associated with MDS, which is the first Korean case.

Molecular genetics (HLA) of Behcet's disease

Behcet's disease (BD) has been known to be strongly associated with the human leukocyte antigen (HLA) B51. This B51 association has been confirmed in many different ethnic groups between the Middle East and Japan, and it has been proposed that BD is prevalent in those ethnic groups along the old Silk Route. The hypothesis could be made that B51 molecules are primarily involved in BD development through specific antigen presentation. However, polymorphic analyses of the TNFB gene and Tau-a microsatellite between the HLA-B and TNF genes indicate that the pathogenic gene of BD is not the HLA-B51 gene itself but another gene located around the HLA-B gene. HLA-C genotyping by the PCR-SSP method also suggests that the BD pathogenic gene is not the HLA-C gene itself but other gene located near the HLA-B gene. Recently we sequenced a single contig of 236,822 bp from the MICA gene (58.2 kb centromeric of HLA-B) to 90.8 kb telomeric of HLA-C and identified 8 novel genes designated NOB1-8 (NOB: new organization associated with HLA-B). During the course of the genomic sequence analysis we clarified the genetic structure of the MICA (MHC class I chain-related gene A) gene and found a triplet repeat microsatellite polymorphism of (GCT/AGC)n in the transmebrane (TM) region. Furthermore, the microsatellite allele consisting of 6 repetitions of GCT/AGC (MICA A6 allele) was present at a significantly higher frequency in the BD patient group than in the control group and a significant fraction of B51-negative patients were positive for this MICA A6 allele. These results suggest the possibility of a primary association of BD with MICA rather than HLA-B.