New insights of HLA class I association to Behçet's disease in Portuguese patients

Ocular Manifestations in Juvenile Behçet's Disease: A Registry-Based Analysis from the AIDA Network

INTRODUCTION

This study aims to characterize ocular manifestations of juvenile Behçet's disease (jBD).

METHODS

This was a registry-based observational prospective study. All subjects with jBD from the Autoinflammatory Diseases Alliance (AIDA) Network BD Registry showing ocular manifestations before 18 years were enrolled.

RESULTS

We included 27 of 1000 subjects enrolled in the registry (66.7% male patients, 45 affected eyes). The median (interquartile range [IQR]) age at ocular involvement was 14.2 (4.7) years. Uveitis affected 91.1% of eyes (anterior 11.1%, posterior 40.0%, panuveitis 40.0%), retinal vasculitis 37.8% and other manifestations 19.8%. Later onset (p = 0.01) and male predominance (p = 0.04) characterized posterior involvement. Ocular complications occurred in 51.1% of eyes. Patients with complications had earlier onset (p < 0.01), more relapses (p = 0.02) and more prolonged steroidal treatment (p = 0.02). The mean (standard deviation [SD]) central macular thickness (CMT) at the enrolment and last visit was 302.2 (58.4) and 293.3 (78.2) μm, respectively. Fluorescein angiography was pathological in 63.2% of procedures, with a mean (SD) Angiography Scoring for Uveitis Working Group (ASUWOG) of 17.9 (15.5). At the last visit, ocular damage according to the BD Overall Damage Index (BODI) was documented in 73.3% of eyes. The final mean (SD) best corrected visual acuity (BCVA) logMAR was 0.17 (0.47) and blindness (BCVA logMAR < 1.00 or central visual field ≤ 10°) occurred in 15.6% of eyes. At multivariate regression analysis, human leukocyte antigen (HLA)-B51 + independently predicted a + 0.35 change in the final BCVA logMAR (p = 0.01), while a higher BCVA logMAR at the first assessment (odds ratio [OR] 5.80; p = 0.02) independently predicted blindness.

CONCLUSIONS

The results of this study may be leveraged to guide clinical practice and future research on this rare sight-threatening condition.

Behçet disease, new insights in disease associations and manifestations: a next-generation sequencing study

Behçet disease is a multi-system disease associated with human leukocyte antigen (HLA) class I polymorphism. High-resolution next-generation sequencing (NGS) with haplotype analysis has not been performed previously for this disease. Sixty Egyptian patients diagnosed according to the International Study Group (ISG) criteria for Behçet disease and 160 healthy geographic and ethnic-matched controls were genotyped for HLA class I loci (HLA-A, B, C). For HLA class II loci (DRB1, DRB3/4/5, DQA1, DQB1, DPA1, DPB1), 40 control samples were genotyped. High-resolution HLA genotyping was performed using NGS and the results were analyzed. Clinical manifestations were oral ulcers (100%), genital ulcers (100%), eye (55%) and neurological (28%) and vascular involvement (35%). HLA-B*51:08 [odds ratio (OR) = 19·75, 95% confidence interval (CI) = 6·5-79; P < 0·0001], HLA-B*15:03 (OR = 12·15, 95% CI = 3·7-50·7; P < 0·0001), HLA-C*16:02 (OR = 6·53, 95% CI = 3-14; P < 0·0001), HLA-A*68:02 (OR = 3·14, 95% CI = 1·1-8·9; P < 0·01) were found to be associated with Behçet disease, as were HLA-DRB1*13:01 and HLA-DQB1*06:03 (OR = 3·39, 95% CI = 0·9-18·9; P = 0·04 for both). By contrast, HLA-A*03:01 (OR = 0·13, 95% CI = 0-0·8; P = 0·01) and HLA-DPB1*17:01 were found to be protective (OR = 0·27, 95% CI = 0·06-1·03; P = 0·02). We identified strong linkage disequilibrium between HLA-B*51:08 and C*16:02 and A*02:01 in a haplotype associated with Behçet disease. HLA-B*51:08 was significantly associated with legal blindness (OR = 2·98, 95% CI = 1·06-8·3; P = 0·01). In Egyptian Behçet patients, HLA-B*51:08 is the most common susceptibility allele and holds poor prognosis for eye involvement.

Association of HLA-B27 and Behcet's disease: a systematic review and meta-analysis

Background

To calculate the genetic impact of the “HLA-B27” allele on the risk of Behcet’s disease (BD) progression using a systematic review and meta-analysis on case control papers.

Methods

A systematic review search was conducted on the MeSH keywords of Behcet’s disease, HLAB27 and B27 in PubMed, Scopus, ProQuest, EMBASE, SID, Magiran, IranDoc and IranMedex databases from 1975 to Aug 2017. Data underwent meta-analysis (random effect model) in CMA2 software. Pooled odds ratios with 95% confidence intervals were calculated for each study. The heterogeneity of the articles was measured using the I² index.

Results

Twenty two articles met the inclusion criteria for 3939 cases and 6077 controls. The pooled OR of “HLA-B27” in BD patients compared with controls was [1.55 (CI 95% 1.01–2.38), P = 0.04]. The OR differ among different countries or geographical areas, focus on domination the European countries. Quality of studies was moderate and heterogeneity was relatively high (I² = 66.9%).

Conclusions

There is a significant correlation between HLA-B27 and Behcet’s Disease, but it was weak. Environmental and genetic factors might determine which the “HLA-B27” alleles manifest Behcet’s disease progression. Future researches is required to perform about what factors can do to positively and separately influence Behcet’s disease.

Beyond Human Leukocyte Antigen Class I Antigens: Hereditary Hemochromatosis Gene Mutations in Recurrent Aphthous Oral Ulcers and Behçet Disease in the South of Tunisia

OBJECTIVE

The aim of this work was to establish human leukocyte antigen (HLA) class I and hereditary hemochromatosis gene (HFE) mutation associations with recurrent aphthous oral ulcers (RAOU) and Behçet disease (BD) in a cohort of Southern Tunisian patients.

SUBJECTS AND METHODS

A total of 232 patients with RAOU and 123 healthy controls (HCs) were enrolled in this study. The patients were divided into 2 groups based on the presence (BD+: n = 62) or absence of BD (BD-, n = 170). In the BD+ group, 28 patients had severe manifestations of BD. In the BD- group, RAOU was isolated in 81 patients, associated with mucocutaneous manifestations in 58 and with joint symptoms in 25. Complement-dependent microlymphocytotoxicity assay and polymerase chain reaction-restriction fragment length polymorphism were used to study HLA class I polymorphism and HFE mutations, respectively.

RESULTS

HLA-B51 was positively associated with BD, particularly in those with severe manifestations. No association was detected with HLA class I polymorphism among the BD group. Based on stratification to clinical manifestations, the isolated RAOU was negatively associated with HLA-A1 with a difference close to significance (12 [14.81%] vs. 32 [26.02%] in HCs; p = 0.06). Furthermore, patients with mucocutaneous features had a higher frequency of HLA-B51 (14, 24.14%) than patients without mucocutaneous involvement (11, 11.37%). Considering HFE mutations, patients with isolated RAOU had a higher frequency of H63D when compared with other subgroups, especially after limiting the comparison to 27 patients of at least 5 years of follow-up.

CONCLUSION

This study showed that, unlike BD, RAOU were not associated with HLA-B51. Moreover, we suggest that H63D mutation was positively associated with isolated RAOU.

Immunopathogenesis of ocular Behçet's disease

Behçet's disease (BD) is a chronic recurrent systemic inflammatory disorder of unknown etiology characterized by oral and genital ulcerations, skin lesions, and uveitis. The ocular involvement of BD, or Behçet's uveitis (BU), is characterized by panuveitis or posterior uveitis with occlusive retinal vasculitis and tends to be more recurrent and sight threatening than other endogenous autoimmune uveitides, despite aggressive immunosuppression. Although pathogenesis of BD is unclear, researches have revealed that immunological aberrations may be the cornerstone of BD development. General hypothesis of BD pathogenesis is that inflammatory response is initiated by infectious agents or autoantigens in patients with predisposing genetic factors and perpetuated by both innate and acquired immunity. In addition, a network of immune mediators plays a substantial role in the inflammatory cascade. Recently, we found that the immunopathogenesis of BU is distinct from other autoimmune uveitides regarding intraocular effector cell profiles, maturation markers of dendritic cells, and the cytokine/chemokine environment. In addition, accumulating evidence indicates the involvement of Th17 cells in BD and BU. Recent studies on genetics and biologics therapies in refractory BU also support the immunological association with the pathogenesis of BU. In this review, we provide an overview of novel findings regarding the immunopathogenesis of BU.

A Case of Human Leukocyte Antigen (HLA) B27-Positive Intestinal Behçet's Disease with Crohn's Disease-Like Anal Fistulas

A 49-year-old male was admitted to our hospital with complaints of perianal pain, bloody stool, and high-grade fever due to perianal abscess. Drainage was carried out; however, the patient’s complaints worsened, and biopsy findings of colonoscopy showed ulcerative colitis-like lesions. The patient was diagnosed as having Behçet’s disease with intestinal involvement, did not have HLA-B51, but did have HLA-B27. We describe a case of Behcet’s disease with colitis, making a differential diagnosis of inflammatory bowel disease difficult.

HLA and non-HLA genes in Behçet's disease: a multicentric study in the Spanish population

Introduction

According to genome wide association (GWA) studies as well as candidate gene approaches, Behçet’s disease (BD) is associated with human leukocyte antigen (HLA)-A and HLA-B gene regions. The HLA-B51 has been consistently associated with the disease, but the role of other HLA class I molecules remains controversial. Recently, variants in non-HLA genes have also been associated with BD. The aims of this study were to further investigate the influence of the HLA region in BD and to explore the relationship with non-HLA genes recently described to be associated in other populations.

Methods

This study included 304 BD patients and 313 ethnically matched controls. HLA-A and HLA-B low resolution typing was carried out by PCR-SSOP Luminex. Eleven tag single nucleotide polymorphisms (SNPs) located outside of the HLA-region, previously described associated with the disease in GWA studies and having a minor allele frequency in Caucasians greater than 0.15 were genotyped using TaqMan assays. Phenotypic and genotypic frequencies were estimated by direct counting and distributions were compared using the χ² test.

Results

In addition to HLA-B*51, HLA-B*57 was found as a risk factor in BD, whereas, B*35 was found to be protective. Other HLA-A and B specificities were suggestive of association with the disease as risk (A*02 and A*24) or protective factors (A*03 and B*58). Regarding the non-HLA genes, the three SNPs located in IL23R and one of the SNPs in IL10 were found to be significantly associated with susceptibility to BD in our population.

Conclusion

Different HLA specificities are associated with Behçet’s disease in addition to B*51. Other non-HLA genes, such as IL23R and IL-10, play a role in the susceptibility to the disease.

New insights into HLA class I association to Behçet's syndrome in Iranian Azari patients

Behçet’s syndrome (BS) is a chronic recurrent inflammatory disorder characterized by oral and genital ulcers and ocular inflammation. BS has a complex genetic etiology. To evaluate the influence of human leukocyte antigen (HLA) class I in BS susceptibility in Iranian Azari population, we studied 290 BS patients and 300 healthy controls. As expected, a high frequency of HLA-B5 was found. Remarkably, HLA-B35 frequency was higher in the patient than control group, and the frequency of HLA-B51, HLA-B52, and HLA-BW4 was significantly elevated. Thus, HLA-B5 and HLA-B35 seem to confer susceptibility to BD in Iranian Azari patients.

Identification of multiple independent susceptibility loci in the HLA region in Behçet's disease

Behçet's disease is an inflammatory disease characterized by recurrent oral and genital ulcers and significant organ involvement. Localizing the genetic association between HLA-B*51 and Behçet's disease and exploring additional susceptibility loci in the human leukocyte antigen (HLA) region are complicated by the strong linkage disequilibrium in this region. We genotyped 8,572 variants in the extended HLA locus and carried out imputation and meta-analysis of 24,834 variants in 2 independent Behçet's disease cohorts from 2 ancestry groups. Genotyped SNPs were used to infer classical HLA alleles in the HLA-A, HLA-B, HLA-C, HLA-DQA1, HLA-DQB1 and HLA-DRB1 loci. Our data suggest that the robust HLA-B*51 association in Behçet's disease is explained by a variant located between the HLA-B and MICA genes (rs116799036: odds ratio (OR) = 3.88, P = 9.42 × 10(-50)). Three additional independent genetic associations within PSORS1C1 (rs12525170: OR = 3.01, P = 3.01 × 10(-26)), upstream of HLA-F-AS1 (rs114854070: OR = 1.95, P = 7.84 × 10(-14)) and with HLA-Cw*1602 (OR = 5.38, P = 6.07 × 10(-18)) were also identified and replicated.

Juvenile spondyloarthropathies

Spondyloarthropathy (or spondyloarthritis) can begin in childhood (defined as individuals less than 16 years of age). These diseases are distinct in childhood, when compared with adult-onset disease. Because of overlapping features, especially sacroiliac joint involvement, diagnostic difficulty may arise from Behcet's disease, as well as familial Mediterranean fever. Despite advances in diagnostic techniques such as magnetic resonance imaging, the diagnosis of juvenile spondyloarthropathy may still be delayed many years from the onset of symptoms. Treatment of juvenile spondyloarthropathy has advanced rapidly in the last several years, with increasing evidence that agents targeting tumor necrosis factor are effective. These agents also have serious complications, including induction of other autoimmune diseases.

Contribution of Hla-B51 in the susceptibility and specific clinical features of Behcet's disease in Tunisian patients

BACKGROUND

Many researchers have tried to investigate the association of HLA-B51 with the severity and the clinical features of BD with conflicting results.

METHODS

We aimed at investigating the association of HLA-B51 with demographical and clinical manifestations as well as the severity of BD, by studying 178 native Tunisian BD patients, fulfilling the International Study group criteria for the BD classification recruited from the Department of Internal Medicine, Rabta Hospital in Tunis and compared with 125 native Tunisian healthy age and sex matching volunteers.

RESULTS

According to our findings, the frequency of HLAB 51 was significantly higher in BD patients than in controls (p<0.001). Positive pathergy test (PPT) (p = 0.01) and retinal vasculitis (p = 0.045), were significantly more frequent in HLA B51(+) patients, while the frequency of arterial aneurysms (p = 0.009) and neurological involvement, especially the parenchymal involvement (p<0.001), were significantly and clearly higher in HLA B51(-) patients. The patients without HLA B51 had a significantly less severe disease (p = 0.001). Discussion/conclusion We conclude that HLA B51 is a predisposing marker for BD in our population as in most ethnic groups. It seems to be associated with a subgroup of BD patients characterized by a higher frequency of ocular involvement and PPT, but a lower frequency of arterial aneurysm and neurological involvement, and a less severe disease course.

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.

Genetic susceptibility to Behcet's disease: role of genes belonging to the MHC region

OBJECTIVE

To review the progress in the field of MHC-related genetic susceptibility to Behçet's disease (BD).

METHOD

Systematic review of the English literature between 1 January 1980 and 31 January 2010 using Medline. Case-control, population-based, observational cohort studies investigating the association between BD and HLA-B*51 subtypes, classical and non-classical HLA alleles and other HLA-related genes were selected. The geographical distribution of BD and these susceptibility genes was also taken into consideration. Case and familial case reports were excluded except for case series with more than two patients.

RESULTS

Ninety articles plus 17 obtained from other sources were included in the systematic review. We have found high evidence that a core component of genetic susceptibility to BD is within the MHC region being primarily related to an HLA-B*51 subtype: HLA-B*5101/B*510101. Moreover, HLA-A*26, HLA-B*15, HLA-B*5701 and TNF-α -1031C were independently associated with BD. Data suggest that other HLA (HLA-C, HLA-DR) and HLA-related [MHC Class I chain-related gene A (MIC-A), TNF-α] genes may play a role in BD co-susceptibility or pathogenesis. Finally, the distinctive geographical distribution of BD suggested an evolutionary selection of HLA-B*51 subtypes as the major susceptibility factors for BD.

CONCLUSION

Further studies must be addressed to clarify the functional relevance of the different genes found to be associated with disease susceptibility and the potential interactions between genes located within and outside the MHC region.