Heterogeneity of ANCA sera showing atypical, peripheral and classical cytoplasmic immunofluorescence patterns.
Atypical (A) ANCA immunofluorescence (IF) patterns have been described in several disease groups. We have previously reported a distinct cytoplasmic A-ANCA in 7-10% of patients with SLE and/or RA. Here, we show that these rheumatic disease associated A-ANCAs are best identified using U937 cells as substrate and that they do not target either a serine proteinase or a peroxidase. Furthermore, these sera immunoprecipitate a 40 kDa or a 42 kDa band using in vivo 35S-amino acid labelled HL60 or U937 cell extracts, respectively. Although these bands are the only one seen with pure A-ANCA sera, they can also be found in addition to the expected bands of PR3 or MPO in up to 30% of bona fide C- or P-ANCA sera. These data confirm and extend our previous observations. They also suggest that target heterogeneity of ANCA antibodies is frequent. Care should thus be taken in interpreting in a cause and effect relationship, an IF pattern or a biological effect produced by a serum with ill documented monospecificity. The exact nature and significance of this (these) new antigen(s) have yet to be clarified.
Dalpé
G
G
Department of Medicine, Faculty of Medicine and University Hospital, University of Sherbrooke, Qc., Canada.
Fernandes
F
F
Richard
C
C
Boire
G
G
Ménard
H A
HA
D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007163:Immunosorbent Techniques; D015473:Leukemia, Promyelocytic, Acute; D009504:Neutrophils / Q000276:immunology*; D009195:Peroxidase / Q000276:immunology; D014407:Tumor Cells, Cultured
D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D007074:Immunoglobulin G; D009195:Peroxidase