Abstract
Polymorphism (variable number of tandem repeats) in the second intron of the interleukin-1 receptor antagonist (IL-1Ra) gene and two single nucleotide polymorphisms at positions −511 and +3954 of the IL-1β gene may be associated with an increased risk of rheumatoid arthritis (RA). This study used sex stratification to investigate a correlation of the three genetic polymorphisms with the risk of RA, on patients with RA and healthy controls. Polymerase chain reaction (PCR) and polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) were performed. The frequencies of the IL-1β+3954 allele and genotype in female patients were significantly different compared with the controls; but in males, only the frequency of the IL-1β+3954 allele was different. The frequency of the IL-1RN genotype in patients was not statistically different compared with the controls; however, the frequency of IL-1RN allele in female patients was different. The association of the three polymorphisms with the susceptibility to RA appears to be significantly affected by gender.