Immunoglobulin from systemic lupus erythematosus serum induces interferon release by normal mononuclear cells

Ig fractions from patients with systemic lupus erythematosus (SLE) were tested with cultured normal peripheral blood mononuclear cells for induction of interferon release. Lymphocyte eluates, euglobulins containing IgG and IgM, and IgG or IgM from DEAE or sucrose gradients all induced interferon production. Lymphocytotoxic antibody in SLE sera showed a high correlation with capacity of isolated Ig fractions to induce interferon. Most interferon produced was of the gamma type. Monoclonal SLE IgM antilymphocyte antibody induced interferon synthesis.