Clinical significance of IgG subclasses of Anti-Sm and U1 ribonucleoprotein antibodies in patients with systemic lupus erythematosus and mixed connective tissue disease

J Clin Immunol. 1991 Nov;11(6):317-25. doi: 10.1007/BF00918797.


IgG subclasses of anti-Sm and anti-U1 ribonucleoprotein (U1 RNP) antibodies were determined using a new clone of the anti-IgG2 antibody (HG2-56F). Although the predominance of IgG1 coincided with previous reports, IgG2 anti-Sm and U1 RNP antibodies were detected in numerous patients. IgG3 anti-Sm antibody significantly correlates with joint involvement and a high titer of anti-DNA antibody. On the other hand, IgG4 anti-U1 RNP antibody significantly correlated with esophageal dilation and muscular involvement. These results may suggest that some IgG subclasses are related to a specific clinical feature or manifestation.

MeSH terms

  • Autoantibodies / classification*
  • Autoantigens
  • Humans
  • Immunoglobulin G / classification*
  • Lupus Erythematosus, Systemic / immunology*
  • Mixed Connective Tissue Disease / immunology*
  • Ribonucleoproteins / immunology
  • Ribonucleoproteins, Small Nuclear
  • snRNP Core Proteins


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