Detection of autoantibodies to nucleolar transcription factor NOR 90/hUBF in sera of patients with rheumatic diseases, by recombinant autoantigen-based assays.
OBJECTIVE
We attempted to clarify the clinical characteristics of Japanese patients with autoantibodies to nucleolar transcription factor NOR 90/hUBF (anti-NOR 90) and to analyze the autoantigenic epitopes recognized by anti-NOR 90.


METHODS
Ninety-one patient sera containing anti-nucleolar antibodies (ANoA) by indirect immunofluorescence were collected. Immunoblottings were performed using recombinant fusion proteins expressed from several cloned complementary DNA (cDNA) encoding the NOR 90/hUBF autoantigen.


RESULTS
Anti-NOR 90 were detected in sera from 9 (9.9%) of 91 patients with ANoA. Seven of these patients were diagnosed as having Sjögren's syndrome, 4 had concomitant rheumatoid arthritis, 1 had concomitant systemic sclerosis (SSc), and 2 had SSc alone. All 9 sera were reactive with more than 2 recombinant fusion proteins from cDNA encoding separate regions on the hUBF polypeptide.


CONCLUSIONS
The results suggest that while anti-NOR 90 antibodies are rare, they are associated with Sjögren's syndrome in Japanese patients, and that autoimmunity is targeted toward at least 2 separate regions (amino acids 89-310 and 310-633) of the hUBF polypeptide.
Fujii
T
T
Keio University School of Medicine, Tokyo, Japan.
Mimori
T
T
Akizuki
M
M
D000368:Aged; D001323:Autoantibodies / Q000032:analysis* / Q000097:blood; D001483:Base Sequence; D002466:Cell Nucleolus / Q000737:chemistry / Q000276:immunology*; D018076:DNA, Complementary / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009697:Nucleolus Organizer Region / Q000276:immunology; D035463:Pol1 Transcription Initiation Complex Proteins; D015995:Prevalence; D011993:Recombinant Fusion Proteins / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D012216:Rheumatic Diseases / Q000453:epidemiology / Q000276:immunology*; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology*
D001323:Autoantibodies; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D000939:Epitopes; D035463:Pol1 Transcription Initiation Complex Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; C063844:transcription factor UBF