Killer cell immunoglobulin-like receptor gene's repertoire in rheumatoid arthritis

Objective: To investigate the role of the killer cell immunoglobulin-like receptor (KIR) gene's repertoire in the pathogenesis of rheumatoid arthritis (RA) in Taiwan. Methods: KIR genotypes were determined in 122 patients with RA and 96 healthy controls by the sequence-specific primer polymerase chain reaction (SSP-PCR) method. Human leucocyte antigen (HLA)-C genotyping was also performed simultaneously in 72 patients and 66 controls by the SSP-PCR method. Results: The total carriage frequency of KIR 2DS4 regardless of corresponding HLA-Cw4 was significantly increased in RA patients compared with controls [p < 0.001, odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.1-3.4, Pc < 0.01]. The total carriage frequency of KIR 2DL1 regardless of corresponding HLA-C also tended to be increased in RA patients (p < 0.02, OR = 2.1, 95% CI = 1.2-3.9, Pc = not significant). The frequency of KIR 2DS4 with corresponding HLA-Cw4 was increased in RA patients in comparison with controls (p = 0.02, OR = 3.2, 95% CI = 1.1-9.4). Moreover, the association of RA with KIR 2DS4 depended on the presence of the corresponding HLA-Cw4. Conclusions: KIR 2DS4 may be a risk factor for susceptibility to RA in Taiwan.