Table 1.
Presenting clinical features and prevalence of autoantibodies in rheumatoid factor positive rheumatoid arthritis (RF + RA), RF-negative RA (RF-RA), and nonRA patients
| RF + RA | RF - RA | Non RA | |
| (n = 70) | (n = 36) | (n = 132) | |
| Age | 47 ± 12 | 44 ± 14 | 39 ± 13* |
| Female | 44 (63) | 27 (75) | 87 (66) |
| Swollen joint count | 13 ± 9 | 16 ± 10 | 2 ± 3* |
| CRP level | 1.9 ± 1.9 | 1.9 ± 2.1 | 1.6 ± 2.4 |
| Multiple erosions | 12 (17) | 7 (19) | 7 (5)* |
| RF | 70 (100) | 0 | 17 (13) |
| ANA | 25 (36) | 10 (28) | 30 (23) |
| ds-DNA | 0 | 0 | 3(2) |
| Anti-SSA | 5 (7) | 2 (6) | 7 (5) |
| Anti-SSB | 2 (3) | 1 (3) | 2 (2) |
| Anti-RNP | 3 (4) | 0 | 3 (2) |
| Anti-Sm | 0 | 0 | 2(2) |
| AFA | 32 (46)† | 3 (8) | 9 (7) |
| Anti-Sa | 18 (26)† | 5(14)‡ | 3 (2) |
| Anti-CCP | 38 (54)† | 5 (14) | 12 (9) |
| AKA | 26 (37)† | 1 (3) | 21 (16) |
| Anti-RA-1 | 23 (33) | 10 (28) | 49 (37) |
| Anti-RA-33 | 2 (2) | 0 | 1 (1) |
All values represent either number of patients (%), or means ± standard deviations. *P<0.01 compared with RA patients; †P<0.01 compared with RF - RA and nonRA; ‡P<0.01 compared with nonRA. CRP, C-reactive protein; ANA, antinuclear antibodies; AFA, antifilaggrin antibody; RNP, ribonucleoprotein; CCP, cyclic citrullinated peptide; AKA, antikeratin antibody.