Anti-citrullinated protein antibody (ACPA) isotype use in patients who experienced disease progression from undifferentiated arthritis (UA) to RA
| ACPA isotype | Baseline (UA) n=67, n (%) | Follow-up (RA) n=67, n (%) | Lost | Gained | p Value McNemar |
|---|---|---|---|---|---|
| IgG1 | 67 (100) | 66 (99) | 1 | 0 | 1 |
| IgG2 | 51 (76) | 44 (66) | 12 | 5 | 0.14 |
| IgG3 | 34 (51) | 35 (52) | 7 | 8 | 1 |
| IgG4 | 64 (96) | 65 (97) | 0 | 1 | 1 |
| IgA | 45 (67) | 41 (61) | 9 | 5 | 0.42 |
| IgM | 39 (58) | 40 (60) | 7 | 8 | 1 |
The isotype profile at baseline compared with the isotype profile after 1 year of follow-up.
RA, rheumatoid arthritis; UA, undifferentiated arthritis.