Clinical studies of antibodies binding polyriboadenylic acid in systemic lupus erythematosus.

Antibodies of polyriboadenylic acid (poly rA) are demonstrated by filter radioimmunoassay in 75% of patients with systemic lupus erythematosus (SLE), in 54% of patients with discoid lupus erythematosus, and in only 0-7% of normal controls and patients with rheumatoid arthritis or Sjögren's syndrome. These antibodies are distinct from antibodies to single- and double-stranded DNA and double-stranded RNA. Poly rA binding is associated with IgM and IgG serum fractions. Because poly rA may have a role in the transcription of mRNA in mammalian cells and viruses, antibodies to poly rA may be important clues to virologic and immunogenetic mechanisms in the pathogenesis of SLE.