HLA-DRB1 allele carrier frequency in RA patients and controls in subjects stratified for the presence of SE.

RA: rheumatoid arthritis, SE: Shared epitope, OR: odds ratio, CI: confidence interval, Allele carrier frequencies are shown in parenthesis (%). Association was tested by Fisher's exact test using 2×2 contingency tables. SE negative: “A/A” or “A/other than SE or A” vs. “other than SE or A/other than SE or A”. SE positive: “SE/A” vs. “SE/other than A”. Allele groups SE, D70, I67, and S1 were as defined in the Materials and Methods section.