INCREASED FREQUENCY OF THE UNCOMMON ALLELE OF A TUMOR-NECROSIS-FACTOR-ALPHA GENE POLYMORPHISM IN RHEUMATOID-ARTHRITIS AND SYSTEMIC LUPUS-ERYTHEMATOSUS

The frequency of the uncommon allele (TNF2) of a polymorphism in the p romoter region of the tumour necrosis factor alpha (TNF alpha) gene in patients with rheumatoid arthritis (RA) and systemic lupus erythemato sus (SLE) was found to be 3 times that of the normal anglo-saxon popul ation. In SLE patients, this allele was strongly associated with HLA-D R3 expression and was also more frequent in patients who did not have malar rash. Functional studies of normal monocyte cytokine production in vitro showed that this genotype was associated with increased IL-1 alpha protein production but there were no differences in the producti on of TNF alpha protein.