Antibodies against Ku protein in sera from patients with autoimmune diseases

Clin Exp Immunol. 1989 Jun;76(3):366-72.


Immunoaffinity-purified Ku protein was used to screen sera from patients with systemic lupus erythematosus (SLE), scleroderma, myositis and Sjögren's syndrome for anti-Ku antibodies in a quantitative immunoblot assay. Sixteen percent of the 159 studied sera were reactive with the Ku protein; significantly increased frequencies of anti-Ku antibodies were found in SLE (19%) and scleroderma (14%) sera. Patients with myositis and Sjögren's syndrome showed similar frequencies. All positive sera had antibodies to the 86 kD subunit of Ku protein; only one serum did not react with 70 kD subunit. Frequencies of other autoantibodies were compared in anti-Ku positive and negative patients. Only anti-Sm antibodies, especially in the absence of anti-nRNP, appear to be associated with the presence of anti-Ku antibodies. A strong correlation between anti-Ku antibodies and the class II HLA antigen DQw1 (89% of the positive sera) was observed, suggesting participation of MHC genes in the mounting of the anti-Ku immune response.

MeSH terms

  • Antigens, Nuclear*
  • Antigens, Surface / immunology*
  • Autoantibodies / analysis*
  • Autoimmune Diseases / diagnosis
  • Autoimmune Diseases / immunology*
  • DNA Helicases*
  • DNA-Binding Proteins / immunology*
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Immunoblotting
  • Immunoelectrophoresis, Two-Dimensional
  • Ku Autoantigen
  • Lupus Erythematosus, Systemic / diagnosis
  • Lupus Erythematosus, Systemic / immunology
  • Male
  • Myositis / diagnosis
  • Myositis / immunology
  • Scleroderma, Systemic / diagnosis
  • Scleroderma, Systemic / immunology
  • Sjogren's Syndrome / diagnosis
  • Sjogren's Syndrome / immunology


  • Antigens, Nuclear
  • Antigens, Surface
  • Autoantibodies
  • DNA-Binding Proteins
  • DNA Helicases
  • XRCC5 protein, human
  • Xrcc6 protein, human
  • Ku Autoantigen