title: Differences in autoantibody response to Th/To between systemic sclerosis and other autoimmune diseases.
abstract: OBJECTIVE
  To examine differences in autoantibody response and immunogenetic background between patients with systemic sclerosis (SSc) and those with other autoimmune diseases who had serum anti-Th/To antibodies.
  
  
  METHODS
  Serum samples from 1048 Japanese patients with various autoimmune diseases were screened for anti-Th/To antibodies using RNA and protein immunoprecipitation assays. The reactivity to RNase P subunits was examined by immunoprecipitating (35)S labelled recombinant Rpp38, Rpp30, and hPop1 produced by in vitro transcription and translation. HLA-DRB1, DQB1, and DPB1 alleles were identified using a polymerase chain reaction followed by a restriction fragment length polymorphism assay.
  
  
  RESULTS
  Serum anti-Th/To antibodies were detected in 14 of 303 patients with SSc and seven of 745 patients without SSc (4.6% v 0.9%; p=0.0003). Similar percentages of patients with and without SSc showed immunoreactivity to Rpp38 and Rpp30, but more patients with SSc than patients without SSc showed a reactivity to hPop1 (93% v 14%; p=0.002). In patients with anti-Th/To antibodies DRB1*1502 or *0802 was detected more often, and the DRB1*0405-DQB1*0401 haplotype less often in patients with SSc than in patients without SSc (79% v 14%, p=0.02, and 7% v 71%, p=0.01, respectively).
  
  
  CONCLUSIONS
  Anti-Th/To antibodies were detected in a small proportion of autoimmune patients lacking clinical features related to SSc. A close relationship between disease expression and anti-hPop1 reactivity as well as HLA class II alleles in anti-Th/To positive patients suggests that the process of anti-Th/To antibody production may be different between patients with and those without SSc.
authors.affiliation: Institute for Advanced Medical Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. kuwanam@sc.itc.keio.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Kuwana
authors.forename: K
authors.initials: K
authors.lastname: Kimura
authors.forename: M
authors.initials: M
authors.lastname: Hirakata
authors.forename: Y
authors.initials: Y
authors.lastname: Kawakami
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology; D029742:Caenorhabditis elegans Proteins; D002503:Centromere / Q000276:immunology; D004268:DNA-Binding Proteins / Q000276:immunology; D004722:Endoribonucleases / Q000276:immunology; D005260:Female; D006682:HLA-DP Antigens / Q000032:analysis; D059868:HLA-DP beta-Chains; D006683:HLA-DQ Antigens / Q000032:analysis; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000032:analysis; D059811:HLA-DRB1 Chains; D006239:Haplotypes; D006609:High Mobility Group Proteins / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D029701:Saccharomyces cerevisiae Proteins; D012595:Scleroderma, Systemic / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; D006682:HLA-DP Antigens; D059868:HLA-DP beta-Chains; C071170:HLA-DPB1 antigen; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D006609:High Mobility Group Proteins; D029701:Saccharomyces cerevisiae Proteins; C071036:To autoantigen; C096787:pop-1 protein, C elegans; D004722:Endoribonucleases; C108353:RPP1 protein, S cerevisiae