Rheumatoid arthritis (RA) is a genetically complex disease with many possible phenotypes. We investigated IL10 and TNFA gene polymorphisms in a group of Swedish women and men with RA compared with healthy individuals to estimate combinations of alleles specific for the disease.
We analyzed 264 patients with RA and 286 healthy controls for biallelic single-nucleotide polymorphisms in the -308 position of the TNFA and in the -1087 position of the IL10 gene by polymerase chain reaction with restriction endonuclease mapping.
The frequencies of the -308 TNFA genotypes were not different in women and men with RA in comparison to the controls. In contrast, frequencies of the GG, AG, and AA -1087 IL10 genotypes were significantly different in women in the investigated groups: 26%, 58%, and 15% for RA patients and 24%, 54%, and 28% for the controls (chi-square = 8.18, p < 0.02). We confirmed this finding in a separate dataset of female patients and controls. The frequencies of the IL10 genotypes in men were similar in the patients and controls. We found no differences in the distribution of the TNFA or IL10 genotypes in relation to rheumatoid factor in the patients.
On the basis of IL10 polymorphism, female patients with RA seem to represent a separate disease subgroup.