Patient characteristics at baseline
| n | 74 |
| Age (mean (SD)) | 61.7 (13.3) |
| Gender: woman (%) | 57 (77.0) |
| Diagnosis, n (%) | |
| IgG4-related disease | 2 (2.7) |
| Connective tissue diseases | 22 (29.7) |
| Rheumatoid arthritis | 33 (44.6) |
| Vasculitis | 17 (23.0) |
| Peripheral B cells, absolute (median (IQR)) | 2.00 (0.00, 32.50) |
| Detectable B cells, n (%) | 38 (51.4) |
| IgG (median (IQR)) (mg/dL) | 820 (646, 1052) |
| IgM (median (IQR)) (mg/dL) | 47 (26, 69) |
| Months between RTX and vaccination (mean (SD)) | 6.9 (6.0) |
| Days between vaccine and laboratory assessment (mean (SD)) | 21.9 (16.6) |
| Concomitant medication, n (%) | |
| Any csDMARD | 42 (56.8) |
| Methotrexate | 24 (32.4) |
| Mycophenolate mofetil | 8 (10.8) |
| Hydroxychloroquine | 7 (9.5) |
| Azathioprine | 5 (6.8) |
| Leflunomide | 4 (5.4) |
| Sulfasalazine | 1 (1.4) |
| Immunoglobulin therapy | 3 (4.1) |
| Prednisone | 22 (29.7) |
| Vaccine, n (%) | |
| mRNA-1273 | 13 (17.6) |
| BNT162b2 | 61 (82.4) |
csDMARD, conventional synthetic disease-modifying antirheumatic drug; RTX, rituximab.