Table 2.
Frequency of antibodies to minor neutrophil antigens in patients positive for anti-neutrophil cytoplasmic antibodies (ANCA) by immunofluorescence but negative for serine protease 3 (PR3) or myeloperoxidase (MPO) by enzyme-linked immunosorbent assay (ELISA) (group 1).
| Diagnosis | IF-P* | No. | PR3 | MPO | BPI** no. (%) | Elastase no. (%) | Cathepsin G no. (%) | Lactoferrin no. (%) |
|---|---|---|---|---|---|---|---|---|
| WG | C | 3 | – | – | 2 (67) | 1 (33) | 2 (67) | 1 (33) |
| IBD | C | 2 | – | – | 1 (50) | 0 (0) | 0 (0) | 0 (0) |
| MPA | C | 1 | – | – | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| Other vasculitis | C | 8 | – | – | 3 (38) | 2 (25) | 6 (75) | 2 (25) |
| Other Dx† | C | 17 | – | – | 8 (50) | 2 (13) | 13 (76) | 3 (19) |
| Total | 31 | – | 14 (45) | 5 (16) | 21 (68) | 6 (19) | ||
| WG | P | 4 | – | – | 1 (25) | 0 (0) | 3 (75) | 1 (25) |
| IBD | P | 7 | – | – | 3 (43) | 0 (0) | 2 (29) | 3 (43) |
| MPA | P | 2 | – | – | 0 (0) | 0 (0) | 0 (0) | 1 (50) |
| Other vasculitis | P | 4 | – | – | 0 (0) | 1 (25) | 1 (25) | 2 (50) |
| Other Dx‡ | P | 14 | – | – | 4 (28) | 4 (28) | 9 (64) | 7 (50) |
| Total | 31 | 8 (26) | 5 (16) | 15 (32) | 14 (23) |
*
Immunofluorescence pattern: C = cytoplasmic; P = perinuclear.
**
BPI = bacterial-permeability increasing protein.
†
Includes idiopathic pulmonary fibrosis, viral infection, dilated cardiomyopathy, proteinuria, cyctic fibrosis, AIDS, haemosiderosis.
‡
Includes Chronic lymphocytic leukemia, renal cell carcinoma, Alzheimer's, myasthenia gravis, arthritis, pneumonia, chronic sinusitis, systemic lupus erythematosus (SLE).