Previous studies suggest that a variable number of tandem repeats polymorphism in the second intron of the interleukin-1 receptor antagonist gene and two single nucleotide polymorphisms at positions -511 and +3954 of the interleukin-1beta (IL-1B) gene are associated with an increased risk of autoimmune diseases. In the present study, we evaluated associations between these genetic factors and an increased risk of rheumatoid arthritis (RA) in a population from Northwest China.
A total of 240 patients with RA and 227 healthy controls from Northwest China were investigated using PCR and PCR-restriction fragment length polymorphism. Genotype and allele distributions and haplotype construction were analyzed.
The genotype and allele distributions of IL-1B +3954 and IL-1RN polymorphisms were significantly different in RA patients compared to controls (p<0.001 and p<0.001; p=0.028, p=0.023, respectively). Significant differences were also observed between the RA and control groups for the haplotypes IL-1B -511C/+3954C/IL-1RN *1, IL-1B -511C/+3954T/IL-1RN *1 and IL-1B -511T/+3954T/IL-1RN *1 [p=0.017, odds ratio (OR) 0.721, 95% confidence interval (CI) 0.551-0.944; p=0.030, OR 2.111, 95% CI 1.060-4.204; and p=0.029, OR 2.909, 95% CI 1.066-7.902, respectively].
These findings suggest that IL-1B +3954 and IL-1RN genetic polymorphisms are associated with a significantly increased risk of RA in this Chinese population.