Association of toll-like receptor 9 gene polymorphism in Chinese patients with systemic lupus erythematosus in Taiwan

The purpose of this study was to determine whether toll-like receptor 9 (TLR9) gene polymorphisms were markers of susceptibility to or severity of systemic lupus erythematosus (SLE) in Taiwanese patients. The study included 211 healthy individuals and 167 Chinese patients with SLE. Polymorphisms of TLR9 [rs2066807 and rs187084 (-1486 T/C)] were typed from genomic DNA. The genotypes, allelic frequencies, and carriage rates were compared between patients with SLE and control subjects. The relationship between allelic frequencies and clinical manifestations of 167 patients with SLE was evaluated. There was no statistically significant difference in TLR9 (rs2066807) gene polymorphism, allelic frequency, and carriage rate between the SLE and control groups. However, for the genotype of TLR9 -1486 T/C (rs187084) polymorphism, there was a statistically significant difference between the SLE and the control groups (P < 0.001, chi(2) = 15.9). Moreover, there was a significant association between the two groups in allelic frequency and carriage rate of the T allele (P < 0.001, chi(2) = 18.5 and P < 0.01, chi(2) = 8.06, respectively). We did not detect any association between the TLR9 genotype and the clinical or laboratory profiles in patients with SLE. The results suggest that the TLR9 -1486 T/C (rs187084), but not TLR9 (rs2066807), polymorphism is related to SLE in Taiwanese patients.