Multifocal motor neuropathy: Response to human immune globulin

Abstract

Multifocal motor neuroparrhy (MMN) is a progressive disorder producing asymmetrical weakness and muscle wasting. Case reports suggest that patients with MMN improve after cyclophosphamide therapy, but not after prednisone or plasmapheresis, Because MMN is likely to be immune mediated, we investigated the therapeutic response to human immue globulin (HIG) in an open, uncontrolled trial. Nine patients, ages 28 to 58 years, had chronic, progressive, asymmetrical, predominantly distral, limb weakness for 5 to 18 years, Sensation was normal, and reflexes were reduced asymmetrically. All had physiological evidence of multifocal motor demyelination with partial motor conduction block, and 7 had elevated serun titers of anti-GMI IgM antibody. All patients were treated with HIG, 106 to 2.4 gm/ kg., given intravenously over 3 to 5 days. Strength inproved in all patients 3 10 days after treatment, with improvement peaking at 2 weeks and lasting for an average of 2 months. The range of functional improvement veried from dramatic to mild. The degree of partial motor conduction block was reduced, at least partially, in 7 to 8 patients. The serum anti-GM1 antibody titers did not change. Repeated courses of HIG resulted in similar improvements. We conculde that HIg may be an effective therapy for patients with MMN.