Clinical and biological features of patients included in the study
| Group | I (n=6) | II (n=6) | III (n=6) | IV (n=10) | V (n = 10) |
| Male/female | 3/3 | 3/3 | 3/3 | 1/9 | 0/10 |
| Mean age (years) | 57 | 57 | 57 | 56 | 61 |
| Presence of rheumatoid nodules | 2 | 2 | 1 | 0 | 1 |
| ESR, median (range) | 88 (32 to 140) | 62 (22 to 80) | 53 (18 to 86) | — | — |
| CRP, median (range) | 73 (32 to 133) | 31 (6 to 61) | 30 (10 to 7) | — | — |
| Positive rheumatoid factor IgM | 6 | 6 | 5 | 4 | 8 |
ESR, erythrocyte sedimentation rate (mm in 1st hour); CRP, C reactive protein (mg litre-1)