Two ELISAs to detect anti-neutrophil cytoplasm antibodies (ANCA) in various vasculitides.
Anti-neutrophil cytoplasm antibodies (ANCA) are present in the serum of patients with Wegener's granulomatosis, microscopic polyarteritis, and some other small vessel vasculitides. There are at least 2 different anti-neutrophil cytoplasm antibodies identified by their distinctive cytoplasmic staining patterns on indirect immunofluorescence examination. The only antigen identified to date is myeloperoxidase which has a perinuclear distribution on alcohol-fixed neutrophils and monocytes. We have established an ELISA that detects all anti-neutrophil cytoplasm antibodies and one specific for anti-myeloperoxidase antibodies. In the ELISA for anti-neutrophil cytoplasm antibodies, all sera with diffuse cytoplasmic or perinuclear neutrophil staining on indirect immunofluorescence examination bound at levels greater than the normal range (34%, m + 4SD). Three convalescent sera that were negative by indirect immunofluorescence examination were also negative in the assay. Positive sera could be detected at a dilution of 2 and inhibition studies showed that the binding was specific for the neutrophil extract. However, the presence of anti-neutrophil antibodies (ANA), anti-mitochondrial antibodies or immune complexes resulted occasionally in binding in the positive range. Where positive binding was noted in non-vasculitic segmental necrotizing glomerulonephritis, the binding could not be inhibited by pre-incubation with the neutrophil extract. The ELISA for ANCA is a sensitive, objective screening technique that can be performed in parallel with the assay for anti-glomerular basement antibodies to exclude the presence of anti-neutrophil cytoplasm antibodies in patients presenting with rapidly progressive glomerulonephritis. The ELISA for anti-myeloperoxidase antibodies may identify a subset of patients with distinct clinical or prognostic features.
Savige
J A
JA
Department of Nephrology, Royal Melbourne Hospital.
Yeung
S P
SP
Gallicchio
M
M
Davies
D J
DJ
D003593:Cytoplasm / Q000276:immunology* / Q000648:ultrastructure; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005455:Fluorescent Antibody Technique; D006801:Humans; D009504:Neutrophils / Q000276:immunology* / Q000648:ultrastructure; D009195:Peroxidase / Q000276:immunology; D012016:Reference Values; D012680:Sensitivity and Specificity; D013194:Staining and Labeling; D014652:Vascular Diseases / Q000097:blood / Q000276:immunology*
D009195:Peroxidase