Therapeutic plasmapheresis in systemic lupus erythematosus. Effect on immune complexes and antibodies to DNA.

The effect of plasmapheresis in 8 patients with systemic lupus erythematosus (SLE) was investigated. Drug treatment was maintained at a constant level for at least 4 weeks before plasmapheresis. Levels of immune complexes were measured by a Raji cell radioimmunoassay, and by a solid-phase C1q-binding assay. Antibodies to ds-DNA and ss-DNA were measured by the Farr assay. In all cases, immune complexes and antibodies were lowered by plasmapheresis. In 5 patients, plasmapheresis was followed by a rapid rebound of complexes and antibody to pretreatment levels. In 3 in whom plasmapheresis was followed by treatment with cyclophosphamide for 1 month, a sustained immunochemical and clinical improvement followed, lasting in 2 cases for up to 3 years.