Comparison of antibody reactivity to peptides in patients and controls. Statistical analysis based on logarithmically transformed OD values. Antibody reactivity in all groups to CON1 (nonhomologous peptide: GKTCPKEIPKGSKNT) was negligible, and reactivity to nonbiotinylated MAG1 was just above background (0.05 OD units). Overall, there was no significant difference between groups. Multivariate analysis identified a significant difference between biotinylated and nonbiotinylated groups (p = 0.001).
| Group | n | Peptide–MAG1, Mean OD (SEM) | OD Range | p | Peptide–CON1, Mean OD (SEM) | Nonbio–MAG1, Mean OD (SEM) |
|---|---|---|---|---|---|---|
| RA | 30 | 0.732 (0.058) | 2.610–0.293 | 0.041 (0.003) | 0.119 (0.006) | |
| IBD | 23 | 0.465 (0.067) | 1.029–0.233 | 0.003* | 0.028 (0.004) | 0.064 (0.013) |
| OA | 29 | 0.473 (0.059) | 1.249–0.126 | 0.001* | 0.098 (0.004) | 0.135 (0.009) |
| N | 43 | 0.517 (0.049) | 1.405–0.151 | 0.002* | 0.073 (0.007) | 0.157 (0.027) |
↵* Statistical difference determined through posthoc analysis of patients with RA as compared to IBD, OA, and N to MAG1. OD: optical density; RA: rheumatoid arthritis; IBD: inflammatory bowel disease; OA: osteoarthritis; N: healthy controls.