Shared epitope and DRB1*0901 in anti-CCP-positive and anti-CCP-negative unaffected family members. Unaffected family members included are first-degree relatives (n = 132) or more distant relatives (n = 34) who had HLA typing and anti-CCP antibody assay results. Odds ratios for risk of positive anti-CCP antibodies due to SE and DRB1*0901 were calculated by comparison of anti-CCP antibody-negative and anti-CCP-positive unaffected relatives.
| HLA-DRB1
Genotype | Anti-CCP-negative (n = 139) N | ANTI-CCP-positive (n = 27) N | OR (95% CI) | p |
|---|---|---|---|---|
| Any SE | 106 | 22 | 1.37 (0.48, 3.90) | 0.554 |
| SE/X | 72 | 15 | 1.38 (0.46, 4.10) | 0.567 |
| SE/SE | 34 | 7 | 1.36 (0.39, 4.71) | 0.628 |
| *0901 | 6 | 4 | 3.86 (1.01, 14.73) | 0.059 |
| SE/*0901 | 5 | 4 | 4.66 (1.16, 18.66) | 0.04 |