"Atypical p-ANCA" in IBD and hepatobiliary disorders react with a 50-kilodalton nuclear envelope protein of neutrophils and myeloid cell lines.
OBJECTIVE
Atypical "antineutrophil cytoplasmic antibodies" (ANCA) are present in patients with ulcerative colitis (UC), primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH). Recently, we showed that atypical p-ANCA react with nuclear envelope proteins of neutrophils. Based on this observation, we aimed to characterize the nuclear antigen recognized by atypical p-ANCA.


METHODS
We prepared cytoplasmic and nuclear extracts of human neutrophils, human HL-60, and murine 32D myeloid cells. Proteins were resolved by 1- and 2-dimensional gel electrophoresis. Reactive proteins were detected by immunoblotting with sera from 118 individuals (UC, 25; PSC, 28; AIH, 35; disease and normal controls, 30). Atypical p-ANCA (n = 64) were affinity-purified against the reactive protein and investigated for their immunofluorescence pattern using confocal microscopy.


RESULTS
Immunoblotting showed reactivity to a myeloid-specific 50-kilodalton nuclear protein with an isoelectric point of pH 6.0 detected in 92% (59 of 64) of the patients with inflammatory bowel or hepatobiliary diseases and atypical p-ANCA. Affinity-purified antibodies against the 50-kilodalton protein gave a nuclear rim-like fluorescence on myeloid cells examined by immunofluorescence microscopy. Affinity-purified antibodies did not recognize antigens in nonmyeloid cells.


CONCLUSIONS
Atypical p-ANCA in UC, PSC, or AIH recognize a 50-kilodalton myeloid-specific nuclear envelope protein.
Terjung
B
B
Division of Digestive and Liver Diseases, Departments of Medicine and Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
Spengler
U
U
Sauerbruch
T
T
Worman
H J
HJ
D000293:Adolescent; D000328:Adult; D000818:Animals; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology*; D000918:Antibody Specificity; D019556:COS Cells; D002458:Cell Fractionation; D002648:Child; D015209:Cholangitis, Sclerosing / Q000276:immunology*; D003093:Colitis, Ulcerative / Q000276:immunology*; D005260:Female; D005455:Fluorescent Antibody Technique; D018922:HL-60 Cells; D006367:HeLa Cells; D019693:Hepatitis, Autoimmune / Q000276:immunology*; D006801:Humans; D007106:Immune Sera; D008099:Liver / Q000166:cytology; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009504:Neutrophils / Q000737:chemistry / Q000276:immunology*; D009685:Nuclear Envelope / Q000737:chemistry / Q000276:immunology*; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry / Q000276:immunology
D019268:Antibodies, Antineutrophil Cytoplasmic; D007106:Immune Sera; D009687:Nuclear Proteins