1. RA n46 Mean age +/- SD (years)47.2 Sex ratio (female/male)14/32 Mean symptom onset +/- SD (months)8.76 Presence of RF (%)86% Presence of anti-CCP (%)100% Number of patients with X-rays erosions for RA and sacroiliitis for SA 100% Table I: Clinical, biological and radiological characteristics of rheumatoid arthritis.

2. 14,4 kDa 18,8 kDa 25 kDa 35 kDa 45 kDa 116 kDa Figure 1 Healthy control sera Secondary Ab RA sera Antigenic targets wrist RA SM Antigenic targets RA SM Wrist Finger Hip Knee RA serum Healthy serum RA serum Healthy serum RA serum Healthy serum RA serum Healthy serum A B

3. Figure 2 Identification of major spots obtained with RA wrist FLS RA FLS RA sera RA FLS P3RA FLS P4 RA FLS P5 1 2 3 4 5 RA sera 1 2 3 4 5 A B

4. Figure 4

5. Table 2: Results of MALDI mass spectrometry analysis of 2D-PAGE isolated FLS cellular proteins. The identities of 40 spots are listed.

6. Figure 5 14,4 kDa 18,8 kDa 25 kDa 35 kDa 45 kDa 116 kDa Antigenic targets: RA FLS

7. Figure 6 Sensitivity Cutoff = 0,55 Sensitivity = 89 % Specificity= 93% p19 p26 p30 p33 p37 0.466 0.605 0.629 0.495 0.618 Coefficient for X axis Western blot strip Antigen Identity Wrist RA FLS AB

8. Figure 7 P37 64 15 19 26 49 82 Mass (kDa) P57 B C 64 15 19 26 49 82 P26 P30 Mass (kDa) A

9. NumberBand nameProtein name MWPI P11021p26 78 kDa Glucose-regulated Protein 74,4 / 75,84,9 / 5 P02545-2 P30 Lamin A/C64 - 65,56,1 - 6,6 P50995 P37 Annexin A1157,97,2 Table 4