Absence of correlation between IL-1 alpha intron 6 polymorphism and rheumatoid arthritis

Several studies have implicated interleukin 1 alpha (IL-1 alpha) in the pathogenesis of rheumatoid arthritis (RA). We analysed IL-1 alpha intron 6 polymorphism in relation to RA (50 patients with RA and 50 healthy controls). The study of a healthy control population confirmed the existence of the different alleles with a frequency similar to that in the Caucasian populations of northern England. Allele and genotype distributions did not differ significantly between the normal and RA populations, although the allele corresponding to 8 repeats was over-represented in the RA population (8 and 14% in the healthy and RA populations respectively). This suggests that IL-1 alpha intron 6 polymorphism could be part of a complex process involving other unidentified genetic factors in the pathogenesis of RA.