To investigate a possible association of Fcgamma receptor IIIA (FcgammaRIIIA) gene polymorphism at position 158 with susceptibility to, and the outcome of, rheumatoid arthritis (RA).
One hundred seventeen RA patients and 142 unrelated healthy control subjects from the same geographic area were studied. Genotyping for FcgammaRIIIA-158V/F was performed by a method based on polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis using amplification-created restriction sites. HLA-DRB1 typing by PCR-sequence-specific oligonucleotide hybridization (reverse hybridization) was also performed.
Allele and genotype distributions in healthy controls were similar to those reported in other populations. The overall distribution of genotypes in the patients was significantly different from that in the controls (P = 0.023, by chi-square test from 3 x 2 contingency table). An overrepresentation of the FcgammaRIIIA-158FF genotype in the patients was observed (for 158FF versus non-158FF P = 0.01, odds ratio [OR] 1.98, 95% confidence interval [95% CI] 1.16-3.4). However, the FcgammaRIIIA-158VF genotype was increased in controls (for 158VF versus non-158VF P = 0.021, OR 0.54, 95% CI 0.32-0.92). No associations were found with any of a series of clinical parameters. Analysis of FcgammaRIIIA-158FF along with shared epitope showed that the presence of both factors increased the susceptibility to RA (P = 0.0009, OR 3.6, 95% CI 1.63-8.01); however, they probably do not interact to produce this effect.
These results indicate that the FcgammaRIIIA-158 genotypes confer differential susceptibility to RA in our study population. Further studies to elucidate the role of this polymorphism in the pathogenesis of RA and other autoimmune diseases are warranted.