Interleukin-1beta and interleukin-1 receptor antagonist gene polymorphisms in rheumatoid arthritis.

The purpose of this study was to evaluate if IL-1beta (IL-1beta promoter and IL-1beta exon 5) and IL-1receptor antagonist (IL-1Ra) gene polymorphisms act as markers of susceptibility to or severity of RA. The study included 104 RA patients and 103 normal controls. No significant difference was observed in the cytokine allelic frequencies of IL-1beta promoter and IL-1beta exon 5 between patients with RA and healthy controls. In addition, there was no significant association in the cytokine carriage rates of I and II allele of IL-1Ra between RA patients and healthy controls. In contrast, the IV allele of IL-1Ra was significantly increased in RA patients with low inflammatory activity (P=0.03). This study indicated that allelic frequency and carriage rate of IL-1beta (IL-1beta promoter and IL-1beta exon 5) and IL-1Ra (I and II allele) do not differ significantly between normal controls and RA patients in Taiwan. However, the carriage rate of IV allele of IL-1Ra was high in the RA patients with low inflammatory activity.