Anti-(U1)RNP and anti-Sm autoantibody profiles in patients with systemic rheumatic diseases: differential detection of immunoglobulin G and M by immunoblotting

Clin Immunol Immunopathol. 1986 Sep;40(3):532-8. doi: 10.1016/0090-1229(86)90198-4.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantibodies / analysis*
  • Autoantigens / immunology
  • Cell Nucleus / immunology
  • Collodion
  • Electrophoresis, Polyacrylamide Gel
  • Female
  • HeLa Cells / cytology
  • Humans
  • Immunoglobulin G / analysis
  • Immunoglobulin M / analysis
  • Lupus Erythematosus, Systemic / immunology*
  • Male
  • Paper
  • Ribonucleoproteins, Small Nuclear*
  • Scleroderma, Systemic / immunology*
  • snRNP Core Proteins


  • Autoantibodies
  • Autoantigens
  • Immunoglobulin G
  • Immunoglobulin M
  • Ribonucleoproteins, Small Nuclear
  • snRNP Core Proteins
  • Collodion