Appearance of first antibody in seropositive RA cases where both antibodies of interest were present in prediagnosis serum. P value for Wilcoxon signed-rank test.
| Comparing Antibodies | No. Cases, +/n | Mean Yrs | p |
|---|---|---|---|
| Comparing anti-CCP2 to anti-CarP-FCS | Mean yrs of anti-CCP2 preceding anti-CarP-FCS | ||
| Anti-CCP2 preceded anti-CarP-FCS | 4/16 cases | 0.13 | |
| Anti-CarP-FCS preceded anti-CCP2 | 0/16 cases | 0.76 | |
| First appearance in same sample | 12/16 cases | ||
| Comparing anti-CCP2 to anti-CarP-Fib | Mean yrs of anti-CCP2 preceding anti-CarP-Fib | ||
| Anti-CCP2 preceded anti-CarP-Fib | 4/12 cases | 0.13 | |
| Anti-CarP-Fib preceded anti-CCP2 | 0/12 cases | 1.01 | |
| First appearance in same sample | 8/12 cases | ||
| Comparing RF-Neph to anti-CarP-FCS | Mean yrs of anti-CarP-FCS preceding RF-Neph | ||
| RF-Neph preceded anti-CarP-FCS | 2/16 cases | 0.81 | |
| Anti-CarP-FCS preceded RF-Neph | 3/16 cases | 0.08 | |
| First appearance in same sample | 11/16 cases | ||
| Comparing RF-Neph to anti-CarP-Fib | Mean yrs of anti-CarP-Fib preceding RF-Neph | ||
| RF-Neph preceded anti-CarP-Fib | 2/7 cases | 1.00 | |
| Anti-CarP-Fib preceded RF-Neph | 1/7 cases | 0.01 | |
| First appearance in same sample | 4/7 cases |
RA: rheumatoid arthritis; anti-CCP2: anticyclic citrullinated peptide antibodies version 2; anti-CarP: anti-carbamylated protein; FCS: fetal calf serum; Fib: fibrinogen; RF: rheumatoid factor; Neph: nephelometry; +/n: n positive over the case/control group size.