Comparison of laboratory data at diagnosis.
| PTU-induced AAV, n = 36 | Primary AAV, n = 174 | p | |
|---|---|---|---|
| ANCA by immunofluorescence | |||
| p-ANCA, n (%) | 34 (94.4) | 137 (78.7) | |
| c-ANCA, n (%) | 1 (2.8) | 37 (21.3) | < 0.05 |
| Atypical ANCA, n (%) | 1 (2.8) | 0 | |
| ANCA by ELISA | |||
| MPO-ANCA only, n (%) | 31 (86.1) | 137 (78.7) | |
| PR3-ANCA only, n (%) | 1 (2.8) | 37 (21.3) | NS |
| PR3-ANCA + MPO-ANCA, n (%) | 4 (11.1) | 0 | |
| Anemia, n (%) | 15 (41.7) | 146 (83.9) | < 0.01 |
| Immunology, n (%) | |||
| ANA positivity | 12 (33.3) | 18 (10.3) | < 0.01 |
| ENA positivity | 3 (8.3) | 3 (1.7) | NS |
| IgG increased | 8 (22.2) | 54 (31.0) | NS |
| IgA increased | 3 (8.3) | 34 (19.5) | NS |
| IgE increased | 3 (8.3) | 29 (16.7) | NS |
| IgM increased | 7 (19.4) | 5 (2.9) | < 0.01 |
| C3 decreased | 3 (8.3) | 41 (23.6) | NS |
| C4 decreased | 1 (2.8) | 21 (12.1) | NS |
| ESR increased | 24 (66.7) | 124 (71.3) | NS |
| CRP increased | 13 (36.1) | 94 (54.0) | NS |
ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; ANA: antinuclear antibodies; ENA: extractable nuclear antigens; ANCA: antineutrophil cytoplasmic antibody; PTU: propylthiouracil; AAV: ANCA-associated vasculitis; MPO: myeloperoxidase; PR3: proteinase 3; NS: nonsignificant.