title: Anti-(U1)RNP and anti-Sm autoantibody profiles in patients with systemic rheumatic diseases: differential detection of immunoglobulin G and M by immunoblotting.
abstract: Autoimmune sera from patients with systemic lupus erythematosus, scleroderma, or both disorders reactive with the (U1)RNP and Sm antigens were analyzed according to their IgG- and IgM-autoantibody profiles by immunoblotting with HeLa nuclear extracts. Anti-(U1)RNP-specific autoantibodies directed against the 68-kDa polypeptide were found to be predominantly of the IgG type, whereas for the other (U1)RNP-specific protein, 33 kDa, a concomitant occurrence of IgG and IgM class autoantibodies was observed for most patients. In contrast, Sm-specific anti-29/28-kDa autoantibodies were found to be more frequently of the IgM than of the IgG type, while Sm-specific anti-16-kDa antibodies of both classes were present simultaneously in most sera. Of the serum collection reported here only one (U1)RNP-specific serum has been found which lacks anti-Sm antibodies of either class. In general, preclassification of sera by immunodiffusion and counterimmunoelectrophoresis corresponds to the IgG but not to the IgM profile as determined by immunoblotting.
mesh_terms: D001323:Autoantibodies / Q000032:analysis*; D001324:Autoantigens / Q000276:immunology; D002467:Cell Nucleus / Q000276:immunology; D003101:Collodion; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006367:HeLa Cells / Q000166:cytology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D010209:Paper; D017411:Ribonucleoproteins, Small Nuclear; D012595:Scleroderma, Systemic / Q000276:immunology*; D055517:snRNP Core Proteins
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D017411:Ribonucleoproteins, Small Nuclear; D055517:snRNP Core Proteins; D003101:Collodion