Plasmapheresis and immunosuppressive drug therapy in myasthenia gravis.

Plasmapheresis combined with prednisone and azathioprine therapy produced striking clinical improvement in five patients with myasthenia gravis who still had moderate to severe disability despite thymectomy, high-dose prednisone therapy and optimal doses of cholinesterase inhibitors. Serial determinations of titers of serum antibody toward the acetylcholine receptor demonstrated a fall to 21 +/- 5 per cent (mean +/- S.D.) of the original levels concurrently with the patients' increasing strength. Clinically improved patients maintained lowered titers, whereas clinical relapses were associated with a rebound in titer. Our results suggest that plasmapheresis will find a place in the management of patients with myasthenia gravis, and they implicate antibodies to acetylcholine receptor as a pathogenic factor in this disease.