Associations of Killer Cell Immunoglobulin-Like Receptor Genes with Rheumatoid Arthritis

Objective : Rheumatoid Arthritis (RA) is an autoimmune and chronic inflammatory disease of unknown etiology. Killer cell immunoglobulin-like receptors are expressed on the surface of natural killer cells and CD28 null T-cells, both present in synovial membrane of RA. Therefore we evaluated the associations of KIR genes with RA. Methods : 16 KIR genes were genotyped in 100 healthy subjects (HS) and 100 RA patients from Western Mexico using PCR-SSP. Differences in KIR genotypes and gene frequencies were assessed using the X 2 test. Results : Gene frequency of KIR2DL3 was lower in RA than in HS ( p = 0.0019), whereas KIR2DL2 and KIR2DS2 were higher in RA than HS ( p = 0.0004 and p = 0.0487, respectively). In addition were identified 38 genotypes (from G1-G38) in both studied groups, and the genotype frequencies of G1, G6 and G14 showed significant differences ( p = 0.0001, p = 0.0208 and p = 0.0300, respectively). Conclusions : The presence of KIR2DL2 , KIR2DS2 and absence of KIR2DL3 are associated with RA. Moreover, two genotypes BX are associated with RA. These results suggest that KIRs can be involved in RA susceptibility.