The existence of genetic variations in a number of cytokines has been considered to influence susceptibility or relate to disease severity in various autoimmune diseases. Among these, single-nucleotide polymorphisms (SNPs) of the tumor necrosis factor alpha (TNF-alpha) promoter at nucleotides -308 and -238 are considered to be protective against inflammation in HLA-B27-positive individuals, whereas the SNP at position -857 has been associated with disease development in anterior uveitis. We investigate a hypothesized association between the TNF-alpha -857 C-to-T, -308 G-to-A, and the TNF-alpha -238 G-to-A SNPs and the presence of HLA-B27-associated uveitis.
Retrospective case-control study.
One hundred fourteen Caucasian patients with HLA-B27-associated uveitis were studied. Mean age of patients was 44.9+/-14 years (range, 16-81), and mean duration of HLA-B27-associated uveitis was 115.6+/-104 months (range, 6 months-51 years). Eighty-six patients (75.4%) suffered from an additional systemic manifestation of the disease. Sixty-three unrelated healthy HLA-B27-positive blood donors and 88 unrelated healthy HLA-B27-negative individuals served as controls.
Genotypes were determined by polymerase chain reaction.
Association of genotypes at positions -857, -308, and -238 of the TNF-alpha gene with disease development.
Frequencies of the TNF-alpha -308GA and TNF-alpha -238GA genotypes were significantly lower in patients with HLA-B27-associated uveitis (6.1% and 0%, respectively) when compared with the HLA-B27-negative control group, 23% at -308 (P = 0.003), and 7.9% at -238 (P = 0.0003). When compared with healthy HLA-B27-positive controls, a significantly lower frequency of the TNF-alpha -238GA genotype was found among patients (6.3%, P = 0.015). The frequency of the TNF-alpha -308GA genotype was also found to be lower in patients than among HLA-B27-positive control subjects, without, however, reaching statistical significance (6.1%, P = 0.07). No difference in frequencies was seen among the different groups for the SNPs at position -857.
Our data suggest that HLA-B27-positive individuals show a higher susceptibility towards development of an intraocular inflammation in the presence of an A allele at nucleotide -238 and, to a lesser degree, at nucleotide -308 of the TNF-alpha gene promoter.
"HLA-B27 is a well-recognized susceptibility allele for idiopathic anterior uveitis and linkage disequilibrium between HLA-B27 and other variants within the human MHC known to confound analyses for additional susceptibility loci in this region. Several previous studies investigating the prevalence of TNF polymorphisms in patients with anterior uveitis have suggested genetic associations, but the inconsistent outcomes may be a result of heterogenous patient cohorts with a mixed number of underlying systemic disease associations or incomplete stratification analyses for HLA-B27 in patient and control groups [45-47]. "
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
"Recent genetic studies endorse such a scenario. Polymorphisms in tumor necrosis factor (TNF; -308A and -238A), which are associated with increased production of the cytokine, are significantly more frequent in HLA-B*27–positive patients . Similarly, HLA-B*27–positive patients with extraocular disease show an association with SNPs in the TNFRSF1A gene (TNFR1) compared to patients with AAU alone . "
[Show abstract][Hide abstract] ABSTRACT: Acute anterior uveitis (AAU) is the most common form of uveitis and is thought to be autoimmune in nature. Recent studies have described genes that act as master controllers of autoimmunity. Protein tyrosine phosphatase type 22 (PTPN22) and Cytotoxic T lymphocyte antigen-4 (CTLA-4) are two of these genes, and single nucleotide polymorphisms (SNPs) in the genes encoding these molecules have been associated with several autoimmune diseases. In this study we have analyzed SNPs in PTPN22 and CTLA-4 in patients with AAU.
The functional protein tyrosine phosphatase type 22 (PTPN22) SNP (R620W rs2476601, 1858C/T), and two CTLA-4 SNPs (rs5742909, -318C/T and rs231775, 49A/G) were analyzed in 140 patients with AAU and 92 healthy controls by sequence-specific primer -polymerase chain reaction (SSP-PCR). Data was analyzed by chi(2) analysis and Fisher's exact test.
There was no significant association between PTPN22 620W, CTLA-4 -318C/T, or CTLA-4 49A/G and AAU. Similarly, there was no association with the three SNPs when patients were classified by race or gender. Finally, there was no association with the presence of ankylosing spondylitis in the patient cohort.
The data do not support an association between SNPs in PTPN22 and CTLA-4, genes regarded as genetic master switches of autoimmunity. This raises the issue of the etiology of AAU and the possibility that it should be regarded as an autoinflammatory rather than an autoimmune condition.
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