title: Specificity of autoantibodies to SS-A/Ro on a transfected and overexpressed human 60 kDa Ro autoantigen substrate.
abstract: The objective of this study was to analyze apparently discrepant results that arose during the use of an indirect immunofluorescence (IIF) assay using transfected HEp-2 cells to detect anti-SS-A/Ro autoantibodies in human sera. Fourteen sera that had SS-A/Ro antibodies as detected on this commercial substrate, but did not have antibodies to SS-A/Ro as determined by double immunodiffusion (ID) or enzyme-linked immunosorbent assay (ELISA), were studied by immunoprecipitation (IP) of radiolabeled cell extracts and full-length recombinant SS-A/Ro. A multi-antigen strip immunoblotting (IB) assay containing both the 52- and 60-kDa antigens was included in the analysis. We confirmed that 12 of 14 of the sera under study had antibodies to SS-A/Ro protein antigens as determined by at least one other immunoassay. One serum had antibodies to hyRNA but no detectable reactivity with the 52- or 60-kDa antigens. One serum remained negative in all assays for SS-A/Ro autoantibodies.
authors.affiliation: McCaig Center for Joint Injury and Arthritis Research, Faculty of Medicine, University of Calgary, Alberta, Canada. fritzler@ucalgary.ca
authors.forename: Marvin J
authors.initials: MJ
authors.lastname: Fritzler
authors.forename: Cheryl
authors.initials: C
authors.lastname: Hanson
authors.forename: Joan
authors.initials: J
authors.lastname: Miller
authors.forename: Theophany
authors.initials: T
authors.lastname: Eystathioy
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000276:immunology*; D012680:Sensitivity and Specificity; D012859:Sjogren's Syndrome / Q000175:diagnosis* / Q000276:immunology; D014162:Transfection; D000099207:SS-A Antigen
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D015415:Biomarkers; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000099207:SS-A Antigen; C116006:RO60 protein, human