The novel –G646A polymorphism of the TNFα promoter is associated with the HLA‐B51 allele in Korean patients with Behçet's disease

UVEOGENE: An SNP database for investigations on genetic factors associated with uveitis and their relationship with other systemic autoimmune diseases

Uveitis is an intraocular inflammatory disease which can lead to serious visual impairment. Genetic factors have been shown to be involved in its development. However, few databases have focused on the information of associations between single nucleotide polymorphisms (SNPs) and uveitis. To discover the exact genetic background of uveitis, we developed an SNP database specific for uveitis, “UVEOGENE,” which includes 370 genes and 918 SNPs covering 14 uveitis entities and 40 populations from 286 PubMed English‐language papers. Stratification analyses by gender, HLA status, and different clinical features were also extracted from the publications. As a result, 371 associations were judged as “statistically significant.” These associations were also shared with Global Variome shared Leiden Open Variation Database (LOVD) (https://databases.lovd.nl/shared/genes). Based on these associations, we investigated the genetic relationship among three widely studied uveitis entities including Behcet's disease (BD), Vogt–Koyanagi–Harada (VKH) disease, and acute anterior uveitis (AAU). Furthermore, “UVEOGENE” can be used as a reliable and informative resource to identify similarities as well as differences in the genetic susceptibility among uveitis and other autoimmune diseases. UVEOGENE is freely accessible at http://www.uvogene.com.

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.

Polymorphisms of tumor necrosis factor-α promoter region for susceptibility to HLA-B27-positive ankylosing spondylitis in Korean population

This study designed to assess the relationship between tumor necrosis factor (TNF)-α promoter polymorphisms and disease susceptibility to human leukocyte antigen (HLA)-B27-positive ankylosing spondylitis (AS). One hundred and nineteen HLA-B27(+) AS patients, 95 HLA-B27(+) healthy controls, and 135 random healthy controls were enrolled in this study. Six single nucleotide polymorphisms (SNPs) of the TNF-α promoter at positions -1031T/C, -863C/A, -857C/T, -646G/A, -308G/A, and -238G/A were analyzed. Differences between groups were evaluated using the chi-square test or Fisher's exact test. Haplotypes from each SNP were constructed, and differences in haplotypic frequencies between groups were evaluated. There were significant differences in the allelic and genotypic frequencies of 1031T/C, -863C/A, and -857C/T TNF-α promoters polymorphisms between HLA-B27(+) AS patients and random controls, but not between patients with AS and HLA-B27(+) healthy individuals. TNF-α polymorphisms did not influence the extra-spinal clinical features in patients with AS. The haplotypic sequence -1031T/-863C/-857C/-308G increased the risk of susceptibility to AS compared to random controls (P (corr) < 0.001, OR = 2.756, 95% CI = 1.894-4.010), whereas the sequence -1031C/-863A/-857C/-308G appeared to be associated with decreased susceptibility to AS compared to random controls (P (corr) = 0.006, OR = 0.396, 95% CI = 0.231-0.679). This study indicates that TNF-α promoter polymorphism between controls and AS patients with HLA-B27(+) genetic background is not associated with susceptibility to AS. However, TNF-α polymorphism, irrespective of HLA-B27, increases risk of susceptibility to AS in general population.

TNF polymorphisms in patients with Behçet disease: a meta-analysis

BACKGROUND AND AIMS

Polymorphisms in the tumor necrosis factor (TNF) gene at the locations -308, -238, -863, -857 and -1031 have been studied in various ethnic groups for possible association with Behçet's disease. The aim of this meta-analysis is to examine the association between polymorphism in the TNF gene at the locations -308, -238, -863, -857 and -1031 and Behçet's disease.

METHODS

A literature review was performed using MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials for original studies published in English up to October 31, 2009 and that examined the association of the TNF-alpha promoter polymorphisms with Behçet's disease. All pooled odds ratios (OR) were derived from random-effects model with its 95% confidence intervals (CI). We assessed statistical heterogeneity among studies using Cochrane Q test and by calculating I(2). The Cochrane collaboration's software program, RevMan 5 was used to prepare and complete this review.

RESULTS

The literature search resulted in 13 studies. Ten studies met the included criteria and thus were selected. Overall, -1031C (OR = 1.35, 95% CI = 1.09-1.68), -238A (OR = 1.51, 95% CI = 1.12-2.04) and -857T (OR = 0.76, 95% CI = 0.58-0.98) had a significant association with Behcet's disease. The pooled estimates for the other polymorphisms were not statistically significantly associated with Behcet's disease; -308A and -863A.

CONCLUSIONS

Behcet's disease was associated with the -1031C, -238A and the -857T promoter polymorphisms in various ethnic groups.

Role of TNF-alpha gene variation in idiopathic childhood ischemic stroke: a case-control study

Etiology of the idiopathic childhood stroke remains unknown. In previous studies, the immunologic process may be involved in the idiopathic stroke. Tumor necrosis factor- alpha (TNF-alpha), an important immune mediator, may contribute to the initiation and progression in the stroke. The main purpose of this study was to investigate correlation of TNF-alpha genetic variation and idiopathic childhood ischemic stroke. Using the direct DNA sequencing method, polymorphisms in the TNF-alpha promoter region were genotyped in 67 Chinese patients with idiopathic childhood stroke and 70 controls. Among totally 7 single nucleotide polymorphisms identified in the TNF-alpha promoter region, the variant of the -863C/A is associated with increased risk of idiopathic childhood ischemic stroke in our study group. TNF-alpha molecule may have genetically as well as functionally an important role in the pathogenesis of idiopathic childhood ischemic stroke in the Chinese population.