Association of TLR2 gene polymorphisms with ocular Behcet's disease in a Chinese Han population

TLR2, TLR4, TLR8, and TLR9 have been reported to be associated with several autoimmune diseases. The current study aimed to explore whether singe nucleotide polymorphisms (SNPs) of these four genes were associated with ocular Behçet's disease (BD), Vogt-Koyanagi-Harada (VKH) syndrome, acute anterior uveitis (AAU) with or without ankylosing spondylitis (AS), or pediatric uveitis in Han Chinese.

Genotyping was performed by PCR-restriction fragment length polymorphism. The first stage study comprised 400 ocular BD patients, 400 VKH syndrome patients, 400 AAU ± AS patients, 400 pediatric uveitis patients and 600 healthy subjects. The second stage included 438 ocular BD patients and 1000 healthy subjects. Allele and genotype frequencies were compared between patients and controls using the χ(2) test. Real-time PCR was used to detect mRNA expression from PBMCs obtained from healthy controls. Levels of TNF-α, IL-6, IL-10, and IL-1beta in culture supernatants were measured by ELISA.

In the first stage study, only the frequencies of the rs2289318/TLR2 genotype A and C allele and rs3804099/TLR2 genotype CT were significantly higher in ocular BD patients (Pc = 0.048; Pc = 0.008; Pc = 0.005, respectively) compared with controls. The second stage and combined studies confirmed the association (Pc = 0.001; Pc = 6.89E-06, Pc = 2.426E-06, respectively). TLR2 mRNA expression in PBMCs was increased in healthy carriers of the CC genotype of rs2289318/TLR2 and TT genotype of rs3804099/TLR2 following stimulation with peptidoglycan (PGN; P = 0.028; P = 0.004, respectively). No effect of the various TLR2 rs2289318 and rs3804099 genotypes on the release of TNF-α, IL-6, IL-10, and IL-1beta could be detected.

This study provides evidence that the TLR2 gene is involved in the susceptibility to ocular BD.