Objective: Proinflammatory cytokines such as interferon-g (IFN-g) play an important role in the pathogenesis of giant cell arteritis (GCA). Interleukin 10 (IL-10) is a Th2 cytokine with a suppressor effect on IFN-g production. We assessed the influence of functional IL-10 gene promoter polymorphisms in susceptibility to GCA in individuals from Northwestern Spain.
Methods: One hundred three patients with biopsy-proven GCA and 226 matched controls from the Lugo region of Northwest Spain were genotyped for IL-10 -1082 G/A (rs1800896) and -592 C/A (rs1800872) promoter single nucleotide polymorphisms (SNP) by Taqman 5' allelic discrimination assay using Taqman predesigned SNP genotyping assays (numbers C_1747360_10 and C_1747363_10, respectively).
Results: A significant difference in the distribution of -1082 G/A genotypes between GCA patients and controls was observed (p = 0.034). It was mainly due to a decreased number of GCA patients carrying the -1082 A/A genotype (23.3%) compared with controls (36.7%) [p = 0.01, corrected p (pc) = 0.03; OR 0.53, 95% CI 0.31- 0.90]. In addition, haplotype analysis showed that the ATA haplotype frequency was slightly decreased (p = 0.05, pc = 0.2; OR 0.6, 95% CI 0.4-1.0), whereas the uncommon GTA haplotype was significantly increased in GCA patients compared with controls (p = 0.00005, pc = 0.0002; OR 8.7, 95% CI 2.2-34.8). CONCLUSION Our results suggest a potential implication of IL-10 -1082 promoter polymorphism in susceptibility to GCA in Northwestern Spain.