Table 2. Assessment of anti-neutrophil cytoplasmic antibodies (ANCA) and ANCA against proteinase 3 (PR3) and myeloperoxidase (MPO) by classical and automated multiplex analysis in one reaction environment.
| Classical testing | CytoBead assay | |||||||||
| ELISA | IIF | ELISA or IIF | ELISA and IIF | MIA | IIF | MIA or IIF | MIA and IIF | |||
| samples (N) | PR3-ANCA | MPO-ANCA | C/P-ANCA | PR3-ANCA | MPO-ANCA | C/P-ANCA | ||||
| GPA (90) | 78 (86.7%) | 3* (3.3%) | 77 (85.6%) | 81 (90.0%) | 77 (85.6%) | 70 (77.8%) | 11* (12.2%) | 83 (92.2%) | 85 (94.4%) | 72 (80.0%) |
| MPA (28) | 0 (0.0%) | 20 (71.4%) | 26 (92.9%) | 26 (92.9%) | 20 (71.4%) | 0 (0.0%) | 24 (85.7%) | 28 (100.0%) | 28 (100.0%) | 24 (85.7%) |
| RA (133) | 0 (0.0%) | 0 (0.0%) | 47 (35.3%) | 47 (35.3%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 47 (35.3%) | 47 (35.3%) | 0 (0.0%) |
| PSC (70) | 31 (44.3%) | 3 (4.3%) | 49 (70.0%) | 53 (75.7%) | 27 (38.6%) | 24 (34.3%) | 1 (1.4%) | 49 (70.0%) | 52 (74.3%) | 21 (30.0%) |
| AIH1 (10) | 3 (30.0%) | 1 (10.0%) | 9 (90.0%) | 9 (90.0%) | 1 (10.0%) | 1 (10.0%) | 1 (10.0%) | 9 (90.0%) | 9 (90.0%) | 2 (20.0%) |
| AIH2 (10) | 1 (10.0%) | 1 (10.0%) | 3 (30.0%) | 3 (30.0%) | 2 (20.0%) | 2 (20.0%) | 1 (10.0%) | 3 (30.0%) | 3 (30.0%) | 3 (30.0%) |
| UC (57) | 10 (17.5%) | 1 (1.8%) | 26 (45.6%) | 29 (50.9%) | 8 (14.0%) | 18 (31.6%) | 1 (1.8%) | 26 (45.6%) | 33 (57.9%) | 10 (17.5%) |
| CD (20) | 0 (0.0%) | 0 (0.0%) | 2 (10.0%) | 2 (10.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 2 (10.0%) | 2 (10.0%) | 0 (0.0%) |
| ID (49) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
| BD (125) | 0 (0.0%) | 0 (0.0%) | 7 (5.6%) | 7 (5.6%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 13 (10.4%) | 13 (10.4%) | 0 (0.0%) |
ANCA were determined by enzyme-linked immunosorbent assay (ELISA), classical indirect immunofluorescence (IIF) on ethanol-fixed neutrophils and multiplex CytoBead assay in patients and controls: 118 patients with ANCA-associated vasculitis, 300 with autoimmune and gastrointestinal diseases, 49 with infectious disorders, and 125 blood donors (BD).
* p<0.05.
AIH, autoimmune hepatitis; BD, blood donors; CD, Crohn's disease; c/p ANCA, cytoplasmic/perinuclear ANCA; GPA, granulomatosis with polyangiitis; ID, infectious diseases; MIA, microbead immunoassay; MPA, microscopic polyangiitis; N, number; PSC, primary sclerosing cholangitis; RA, rheumatoid arthritis; UC, ulcerative colitis.