Spontaneous in vitro production of anti‐DNA and anti‐RNA by systemic lupus erythematosus and normal peripheral blood mononuclear cells

The spontaneous in vitro production of anti‐DNA and anti‐RNA by peripheral blood mononuclear cells (PBMC) from patients with systemic lupus erythematosus (SLE) and from normal subjects was evaluated employing sensitive solid‐phase assays that are specific for these antibodies. PBMC from SLE patients produced more IgG anti‐DNA and anti‐RNA than did normal PBMC (P < 0.01). In vitro production of IgG anti‐DNA appeared to correlate with serum DNA bindings (r = 0.72, P < 0.005). Similar amounts of IgM anti‐DNA and anti‐RNA were produced by both SLE and normal PBMC. However, IgM anti‐DNA antibodies always appeared to be directed against determinants on denatured DNA. Only PBMC from SLE patients produced IgG antibodies to native DNA.