Schematic classification of RA susceptibility loci into three categories depending on their association pattern in anti-CCP positive and negative RA
| Category | Associations | Locus Name |
|---|---|---|
| 1 | Both CCP positive and negative RA, stronger in CCP positive RA | HLA-DRB1 SE, PTPN22, TNFAIP3 locus 1 |
| 2 | Both CCP positive and negative RA, equally strong in both | ANKRD55, BLK, C5orf30, STAT4 |
| 3 | CCP positive RA only, significant difference between CCP positive and negative RA | AFF3 locus 1, CCR6, CCL21 locus 2, IL2RA locus 2, CD28, CD40, PXK, REL, RBPJ, TNFRSF14, TNFAIP3 locus 3 |
| Not classifiable | CCP positive RA only, but no significant difference between CCP positive and negative RA | All others |
CCP, cyclic citrullinated peptide; RA, rheumatoid arthritis.