Analysis of a Functional IL-6 Gene Polymorphism in HLAB27 Associated and Intermediate Uveitis Gives New Insight in Disease Pathogenesis and Commonality with Other Autoimmune Diseases.

PURPOSE: Interleukin 6 (IL-6) plays a crucial role in both adaptive and innate immunity. The rs1800795 gene polymorphism of IL-6 is associated with various autoimmune diseases, like multiple sclerosis. METHODS: 134 patients with HLAB27 positive iridocyclitis, 84 patients with intermediate uveitis, 132 controls, and 65 HLAB27 positive controls were recruited for the present case-control study. Main outcome measures were genotype distribution and allelic frequencies determined by polymerase chain reaction. RESULTS: The frequency of carriers of the minor allele for rs1800795 was significantly higher in patients with intermediate uveitis compared to controls (p = 0.04; OR: 1.46; CI: 1.02-2.11). Frequencies of the minor allele for rs1800795 did not differ significantly in patients with HLAB27 associated uveitis when compared to controls (p > 0.05). CONCLUSION: These findings further deepen our understanding of the commonality between multiple sclerosis and intermediate uveitis. Given the functionality of the investigated polymorphism, new pathophysiological insights are gained that help to evaluate possible therapeutic targets.

Associations of Independent IL2RA Gene Variants with Intermediate Uveitis.

PURPOSE: The genetic background for the concomitance of uveitis and other autoimmune diseases remains elusive. Here the role of two IL2RA gene variants (rs11594656 and rs12722495) was investigated in intermediate uveitis and HLAB27 acute anterior uveitis. MATERIALS AND METHODS: One hundred fifty-nine patients with HLAB27 acute anterior uveitis, 85 patients with intermediate uveitis, 138 HLAB27 negative controls and 100 HLAB27 positive controls were recruited for this case-control study. Main outcome measures were genotype distribution and allelic frequencies determined by polymerase chain reaction. RESULTS: The frequencies of carriers of the minor allele at rs11594656 and rs12722495 were significantly different in patients with intermediate uveitis compared to HLAB27 positive and negative controls combined (p<0.05). For rs12722495 the minor G allele was protective (genotypic OR: 0.29 [0.12-0.69]), and for rs11594656 the minor A allele conferred risk (genotypic OR: 1.59 [1.09-2.32]). No significant differences in genotype distribution were found between patients with HLAB27 acute anterior uveitis and HLAB27 positive or negative control subjects. CONCLUSIONS: We found rs11594656 and rs12722495 to be associated with intermediate uveitis but not with HLAB27 acute anterior uveitis. The genetic heterogeneity found at the IL2RA locus could help explain patterns of concomitance with other autoimmune diseases.

Association analysis of TGFBR3 gene with Behçet's disease and idiopathic intermediate uveitis in a Caucasian population.

BACKGROUND: Transforming growth factor ß (TGFß) is an important immunoregulatory cytokine in regulatory T cell (Treg) and Th17-mediated pathology, including uveitis due to Behçet's disease (BD). Of the three isoforms, TGFß2 is found at highest levels in the aqueous humour of uninflamed eyes. TGFß signals through a cell-surface receptor comprising three subunits (TGFBR1, 2 and 3). TGFBR3 is considered necessary for TGFß2 signal transduction, but not for other isoforms. A polymorphism in TGFBR3 (rs1805110) has previously been identified in Han Chinese patients with BD. We investigated the frequency of this polymorphism in a Caucasian population with BD and idiopathic intermediate uveitis (IIU). METHODS: The single-nucleotide polymorphism (SNP) rs1805110 in TGFBR3 was genotyped in 75 BD patients, 92 IIU disease controls and 85 disease-free controls. The association with both diseases was analysed using Fisher's exact test. RESULTS: No significant difference in rs1805110 allele or genotype frequency was observed. A low frequency of the T allele was observed (5.88% control, 9.33% BD, 10.33% IIU) with the TT genotype absent in patients with BD and IIU (1.18% control, 0% BD and 0% IIU). Stratification analysis according to clinical features of BD did not associate with the tested SNP. CONCLUSIONS: RS1805110 is not associated with BD or IIU in Caucasian patients. The T allele frequency is consistent with that presented for Caucasian populations in the HapMap database (p>0.05). Our results differ from the previous analysis in Han Chinese patients (p<0.0001), however, the possibility of having a much smaller effect due to the low minority frequency cannot be excluded.

Tumor necrosis factor polymorphisms associated with tumor necrosis factor production influence the risk of idiopathic intermediate uveitis.

PURPOSE: Idiopathic intermediate uveitis (IIU) is a potentially sight-threatening inflammatory disorder with well-defined anatomic diagnostic criteria. It is often associated with multiple sclerosis, and both conditions are linked to HLA-DRB1*15. Previously, we have shown that non-infectious uveitis (NIU) is associated with interleukin 10 (IL10) polymorphisms, IL10-2849A (rs6703630), IL10+434T (rs2222202), and IL10+504G (rs3024490), while a LTA+252AA/TNFA-238GG haplotype (rs909253/rs361525) is protective. In this study, we determined whether patients with IIU have a similar genetic profile as patients with NIU or multiple sclerosis. METHODS: Twelve polymorphisms were genotyped, spanning the tumor necrosis factor (TNF) and IL10 genomic regions, in 44 patients with IIU and 92 population controls from the UK and the Republic of Ireland. RESULTS: IIU was strongly associated with the TNFA-308A and TNFA-238A polymorphisms. We found the combination of TNFA-308 and -238 loci was more strongly associated with IIU than any other loci across the major histocompatibility complex, including HLA-DRB1. CONCLUSIONS: TNF polymorphisms, associated with increased TNF production, are highly associated with IIU. These results offer the potential to ascribe therapeutic response and risk (i.e., the influence of HLA-DRB1*15 status and TNFR1 polymorphism) to anti-TNF therapy in IIU.

CTLA-4 polymorphisms are not associated with ocular inflammatory disease.

Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is regarded with other molecules such as HLA, PTPN22 and CARD15 as genetic master switches of autoimmunity. Single nucleotide polymorphisms (SNPs) in the genes encoding these molecules have been associated with autoimmune conditions. We analysed the SNPs -318C/T and 49A/G in CTLA-4 in patients with Behcet's disease (BD), patients with intermediate uveitis and appropriate controls. Blood was collected from 236 patients with BD from the UK and the Middle East (ME), all fulfilling the International Study Group criteria for the diagnosis of BD, and 143 patients with idiopathic intermediate uveitis were recruited from the Medical Eye Unit at St Thomas' Hospital. Samples from healthy individuals from each geographical centre were used as controls. DNA was prepared by standard methods, and SNPs -318 and 49 in CTLA-4 were detected by a polymerase chain reaction-sequence specific primers (PCR-SSP) assay using primer mixes. The results showed that there was no association with either polymorphism in patients with BD from the UK or the ME. Similarly, there was no association in patients with intermediate uveitis. Moreover, there was no association with SNP in CTLA-4 and disease manifestations in BD or outcome in patients with intermediate uveitis. Both BD and intermediate uveitis have HLA associations, but there is no difference in distribution of CTLA-4 polymorphisms that are associated with other autoimmune diseases. The lack of association with polymorphisms in CTLA-4 and other master controlling genes of autoimmunity suggests that mechanisms that mediate such a description for BD and intermediate uveitis have still to be elucidated.

Are cytokine gene polymorphisms associated with outcome in patients with idiopathic intermediate uveitis in the United Kingdom?

BACKGROUND/AIM: Competing levels of cytokines, either locally within the eye or systemically, may influence the eventual outcome of ocular inflammation. Polymorphism in the promoter part of the genes controlling cytokine production may result in either higher or lower production of the relevant cytokine to a given stimulus. The authors hypothesised that such polymorphisms may relate to visual outcome in patients with idiopathic intermediate uveitis. METHODS: DNA was obtained from 125 patients with idiopathic intermediate uveitis and analysed for the interleukin 10 IL-10-1082G/Alpha and IL-10-819C/T, and interferon gamma IFNgamma 874T/A gene polymorphisms. Associations with disease were calculated by both allelic frequency and haplotype analysis, and associations between ocular disease outcomes and the presence of polymorphisms were identified. A bad outcome was defined as loss of vision <6/12 Snellen in both eyes at 5 years from presentation when the eyes were quiet. RESULTS: An initial screen showed that the 874T allele of the IFNgamma gene was more prevalent in patients than controls (chi2= 7.9; p = 0.004 OR 1.7; 95% CI 1.2 to 2.6 (Pc = 0.02), whereas the IL-10-1082/-819 AT haplotype of the interleukin 10 (IL-10) gene was not. Analysis of disease outcome showed an association between IL-10-1082 AA homozygosity and bad outcome (chi2= 13; p = 0.0003). Moreover, the two cytokine polymorphisms taken together showed that up to 75% of patients with a poor visual outcome had the combined IFNgamma 874TA or TT genotype together with the IL-10-1082AA genotype (chi2= 13.2 p = 0.0008 OR 6.4; 95% CI 1.85 to 23.6 Pc = 0.1). CONCLUSION: These results show that disease outcome in intermediate uveitis may be partly determined by a complex interplay between cytokine genes and these results may have implications for future treatment with biological agents that target these cytokines.