Development and comparative evaluation of immunoblot assays for detecting autoantibodies to Scl 70 and Jo 1 antigens in serum.
We developed rapid 24-h immunoblot assays for detecting autoantibodies to Scl 70 and Jo 1 antigens in serum. In comparative studies, we evaluated the analytical sensitivity of the immunoblot assays and commercial immunodiffusion assays for anti-Scl 70 and anti-Jo 1 autoantibodies with the use of positive control sera, and compared the frequencies of positive and negative results in a group of 116 sera, including specimens from 34 healthy controls and 82 patients with various connective-tissue diseases. The immunoblot assays were greater than 100-fold more sensitive than immunodiffusion for detecting both autoantibodies. Despite greater analytical sensitivity, there were no false-positive results by the immunoblot assay for anti-Scl 70 or anti-Jo 1 autoantibodies in sera from either the controls or the patients. The diagnostic sensitivity of the immunoblot assay for anti-Scl 70 autoantibodies in patients with scleroderma was greater than that of the immunodiffusion assay, 70% vs 20%, and was equivalent in patients with polymyositis, 43%. We conclude that rapid immunoblot assays for anti-Scl 70 and anti-Jo 1 autoantibodies are superior to immunodiffusion assays for clinical use and are suitable for routine use in the clinical laboratory.
Fonong
T
T
Mayo Clinic and Foundation, Section of Clinical Immunology and Cell Kinetics, Rochester, MN 55905.
Evans
S M
SM
Homburger
H A
HA
D001323:Autoantibodies / Q000302:isolation & purification; D003240:Connective Tissue Diseases / Q000097:blood / Q000175:diagnosis; D004264:DNA Topoisomerases, Type I; D006643:Histidine-tRNA Ligase / Q000097:blood*; D006801:Humans; D015151:Immunoblotting / Q000379:methods*; D009687:Nuclear Proteins / Q000097:blood*
D001323:Autoantibodies; D009687:Nuclear Proteins; C048100:Scl 70 antigen, human; D004264:DNA Topoisomerases, Type I; D006643:Histidine-tRNA Ligase