--Disease Characteristics-- Chronic inflammatory demyelinating polyneuropathy (CIDP), i.e.: Progressive or relapsing motor and sensory dysfunction of more than 1 limb over at least 2 months Hypo- or areflexia of at least 2 limbs No myelopathy No central demyelination No drug or toxic exposure known to cause peripheral neuropathy --Prior/Concurrent Therapy-- No prior corticosteroids or other immunomodulators for CIDP No prior plasmapheresis At least 30 days since participation in other investigational study At least 6 months since the following: Cyclophosphamide Intravenous immune globulin Cyclosporine Interferon alfa Azathioprine Corticosteroids Orthoclone Tacrolimus --Patient Characteristics-- Hepatic: No hepatitis Renal: Not specified Neurologic: Cerebrospinal fluid (CSF) protein greater than 50 mg/dL CSF cell count less than 10 CSF VDRL negative 3 of the following motor abnormalities by electrophysiology: Reduced conduction velocity in 2 or more motor nerves Less than 80% of normal if amplitude greater than 80% of normal Less than 70% of normal if amplitude less than 80% of normal Conduction block or abnormal temporal dispersion in 1 motor nerve No ulnar or peroneal nerve entrapment Prolonged distal latency in 2 or more nerves Greater than 125% of normal if amplitude greater than 80% of normal Greater than 150% of normal if amplitude less than 80% of normal Absent F-waves or H response (patients aged under 60) or prolonged shortest F-wave latency in 10 to 15 trials in 2 or more motor nerves Other: No hypersensitivity to immune globulin No IgA deficiency No mutilation of hands or feet No retinitis pigmentosa No ichthyosis No disease that would limit neuromuscular assessment No endocrinopathy No connective tissue disease or vasculitis No Lyme disease No malignancy No Castleman's disease No hyper- or hypothyroidism No HIV infection No alcohol or drug abuse No pregnant or nursing women