Toll-like Receptor Genes Confer Susceptibility To Autoimmune Uveitis In A Chinese Han Population

Uveitis is a common and important eye disease which can causeblindness. There are about30-50million patients with uveitis in China andquite a few of them have no chance to recover their sight. Uveitis, themajority of which have occurred in young adult population, is one of themain global causing blindness. However, the pathogenesis of uveitis is notclear in present. Toll-like receptors (TLRs) are thought to be one of thelinks between infection and autoinflammatory or autoimmune disease.TLRs are members of the family of pattern recognition receptors (PRRs),which represent the main innate immune sensors. Thirteen distinctmammalian TLRs, so far, have been identified, ten of which are functionalin humans (TLR1-10). TLRs that include TLR2,4,7,8,9have been shownto play a role in the pathogenesis of various inflammatory diseasesincluding uveitis. Relations were reported between polymorphisms or copynumber variants of TLRs and several autoimmune diseases. Based on thesefindings that TLRs play an important role in the pathogenesis of these various inflammatory diseases, we investigated the following two studies:1.To discuss the relationship between polymorphisms of TLRs genes anduveitis, including Beh et disease, VKH syndrome, and Acute anterioruveitis associated with or without Ankylosing spondylitis, in a Chinese Hanpopulation.2. To discuss the relationship between copy number variants ofTLRs genes and uveitis, including Beh et disease, VKH syndrome, andAcute anterior uveitis associated with or without Ankylosing spondylitis, ina Chinese Han population. Through the two studies, we may not only havea further knowledge concerning the susceptibility for uveitis, but also offera novel therapeutic method for uveitis.Part Ⅰ Association of TLRs genes polymorphisms withuveitis in a Chinese Han populationPurpose: TLR2, TLR4, TLR8and TLR9have been reported to beassociated with several autoimmune diseases. The current study aimed toexplore whether SNPs of these four genes were associated with ocularBehcet’s disease (Beh et), Vogt-Koyanagi-Harada (VKH) syndrome, acuteanterior uveitis (AAU) with or without ankylosing spondylitis (AS) in HanChinese.Methods: Genotyping was performed by PCR-RFLP. The first stage studycomprised400ocular Beh et patients,400VKH syndrome patients,400 AAU+AS±patients and600healthy subjects. The second stage included438ocular Beh et patients and1000healthy subjects. Allele and genotypefrequencies were compared between patients and controls using the χ2test.Real-Time PCR was used to detect mRNA expression from PBMCsobtained from healthy controls. Levels of TNF-α, IL-6, IL-10and IL-1betain culture supernatants were measured by ELISA.Results: In the first stage study, only the frequencies of thers2289318/TLR2genotype CC and C allele and rs3804099/TLR2genotypeCT were significantly higher in ocular Beh et patients (pc=0.048; pc=0.008; pc=0.005, respectively) compared with controls. The second stageand combined studies confirmed the association (pc=0.001; pc=6.89E-06,pc=2.426E-06, respectively). TLR2mRNA expression in PBMCs wasincreased in healthy carriers of the CC genotype of rs2289318/TLR2andTT genotype of rs3804099/TLR2following stimulation with peptidoglycan(PGN)(p=0.028; p=0.004, respectively). No effect of the various TLR2rs2289318and rs3804099genotypes on the release of TNF-α, IL-6, IL-10and IL-1beta could be detected.Conclusion: This study provides evidence that the TLR2gene is involvedin the susceptibility to ocular Beh et. Part Ⅱ Association of TLRs genes copy number variants withuveitis in a Chinese Han populationPurpose: TLRs have been reported to be associated with severalautoimmune diseases. The current study aimed to explore whether copynumber variants (CNVs) of the TLRs genes were associated with ocularBehcet’s disease (Beh et), Vogt-Koyanagi-Harada (VKH) syndrome, acuteanterior uveitis (AAU) with or without ankylosing spondylitis (AS) in aChinese Han population.Methods: CNVs of the TLRs were detected by Real-time PCR. The firststage study comprised400ocular Beh et’s disease patients,400VKHsyndrome patients,400acute anterior uveitis associated with or withoutankylosing spondylitis (AAU+AS±) patients and600healthy subjects froma Chinese Han population. The second stage included another set of578ocular Beh et’s disease patients and1000healthy Chinese Han subjects.The frequencies of TLRs genes copy number types were comparedbetween patients and controls using the χ2test. Real-Time PCR was usedto detect mRNA expression from PBMCs obtained from healthy controls.Levels of TNF-α, IL-6and IL-1β in culture supernatants were measured byELISA.Results: In the first stage study, we found a significantly increasedfrequency of more than one copy of TLR7in male Beh et’s disease patients and more than two copies in female patients (Pc=0.021, OR=2.452,95%CI=1.440to4.176; Pc=0.048, OR=2.620,95%CI=1.406to4.882, respectively). No associations could be detected for VKH orAAU+AS±. A second stage and combined study confirmed the associationof the increased frequency of more than one copy of TLR7in male andmore than two copies in female with ocular Beh et’s disease (pc=1.14E-06,OR=2.324,95%CI1.680to3.215; Pc=9.12E-05, OR=2.492,95%CI=1.603to3.873, respectively). TLR7mRNA expression in PBMCs wasincreased in male healthy carriers of more than one copy of TLR7orfemale of more than two copies following stimulation with R848(P=0.021, P=0.006, respectively). No effect of the various TLR7copies onthe release of TNF-α, IL-6and IL-1β could be detected. A significantlyhigher frequency of more than one copy of TLR7was also noticed in maleBeh et’s disease patients with the skin lesions.Conclusions: This study for the first time provides evidence that a highcopy number of TLR7confers risk for ocular Beh et’s disease in a ChineseHan population.