High-Dose Intravenous Immune Globulin for Stiff-Person Syndrome

Patients with stiff-person syndrome, a disabling central nervous system disease with no effective therapy, are plagued by muscle rigidity and episodes of muscle spasm. Patients have high titers of antibodies against glutamic acid decarboxylase (anti-GAD65), suggesting an autoimmune pathogenesis. In this study, 16 patients were randomly assigned to receive either placebo or intravenous immune globulin for three months, followed by a washout period and then three months of therapy with the other agent. Eleven of the 14 patients who completed the study had a marked improvement in their condition with active therapy. High-dose immune globulin is effective therapy for patients with stiff-person syndrome and anti-GAD65 antibodies. Stiff-person syndrome is a rare central nervous system disorder characterized by rigidity of truncal and proximal limb muscles with intermittent superimposed spasms. 1 – 4 Continuous contractions of agonist and antagonist muscles caused by the involuntary firing of motor units at rest are the clinical and electrophysiologic hallmarks of the disease. 5 – 7 The cause of stiff-person syndrome is unknown, but an autoimmune pathogenesis is suspected for several reasons. Circulating antibodies against glutamic acid decarboxylase (GAD65) are characteristic of the disease 8 , 9 and have distinct epitope specificity. 8 – 12 These antibodies are produced intrathecally and may be pathogenic because they inhibit the activity and . . .