No direct correlation between serum antiacetylcholine receptor antibody levels and clinical state of individual patients with myasthenia gravis.

Serum acetylcholine receptor antibodies were measured serially in myasthenia gravis patients before and after early extended thymectomy; they received no medication postoperatively. Clinical improvement occurred with little or no change in antibody level. After plasmapheresis without immunosuppressive drug therapy, we also found clinical improvement without decrease in serum antibody level.