Shared epitope and DRB1*0901 in RA probands and controls.
| HLA-DRB1 Genotype | Controls (n = 176) N | All RA (n = 250) N | OR (95% CI) Controls vs RA | CCP+RA (n = 101) N | OR (95% CI) Controls vs CCP+RA | CCP–RA (n = 22) N | OR (95% CI) Controls vs CCP–RA |
|---|---|---|---|---|---|---|---|
| Any SE | 116 | 210 | 2.72 (1.72, 4.30) p < 0.0001 | 84 | 2.56 (1.39, 4.69) p = 0.002 | 17 | 1.76 (0.62, 5.00) p = NS |
| SE/X | 71 | 124 | 2.62 (1.60, 4.30) p < 0.0001 | 45 | 2.24 (1.16, 4.31) p = 0.015 | 13 | 2.20 (0.74, 6.52) p = NS |
| SE/SE | 45 | 86 | 2.87 (1.67, 4.91) p < 0.0001 | 39 | 3.06 (1.54, 6.09) p = 0.001 | 4 | 1.07 (0.27, 4.20) p = NS |
| Any *0901 | 12 | 33 | 2.08 (1.04, 4.15) p = 0.035 | 15 | 2.38 (1.07, 5.32) p = 0.030 | 2 | 1.37 (0.29, 6.55) p = NS |
| SE/*0901 | 3 | 18 | 4.47 (1.30, 15.43) p = 0.010 | 7 | 4.29 (1.09, 17.0) p = 0.025 | 0 | 0.98 (0.96, 1.0) p = NS |
CCP: cyclic citrullinated peptide; N = number with genotype; SE: shared epitope. Any SE: genotypes with SE in combination with any DRB1 allele including SE. Any *0901: genotypes with *0901 in combination with any DRB1 allele. SE/X: genotypes with SE in combination with non-SE DRB1 allele. SE/*0901: genotypes with SE in combination with *0901. Odds ratios for RA were calculated for any SE, SE/X, and SE/SE genotypes versus genotypes without SE, or any *0901 genotypes versus genotypes without *0901, and for SE/*0901 genotypes versus any other genotypes.