Phase III Randomized, Double-Blind, Sham-Controlled Study of Plasma Exchange for Acute Severe Attacks of Inflammatory Demyelinating Disease Refractory to Intravenous Methylprednisolone

PROTOCOL ENTRY CRITERIA: --Disease Characteristics-- * Idiopathic inflammatory demyelinating syndrome, as follows: biopsy-proven if necessary - established diagnosis of multiple sclerosis (MS) using Poser criteria; acute disseminated encephalomyelitis; Marburg's variant of MS Balo's concentric sclerosis * Eligible without biopsy: acute transverse myelitis; Devic's syndrome * Acute neurologic deficit markedly affecting consciousness, language, or brainstem/spinal cord function, i.e., aphasia, paraplegia, coma, quadriplegia, hemiplegia, severe organic brain syndrome * Deficit unresponsive to 5 days of high-dose intravenous methylprednisolone (MePRDL), as follows: deficit duration of 21 days to 3 months AND no improvement 14 days after beginning MePRDL OR deficit duration of 12 to 20 days AND continued deterioration after completion of MePRDL * No chronically progressive demyelinating disease * No HIV-associated demyelinating syndrome * No progressive multifocal leukoencephalopathy * No optic neuritis --Prior/Concurrent Therapy-- * No more than 3 months of prior steroid therapy Failure on prior MePRDL required Minimum dose 7 mg/kg per day for 5 days * At least 6 weeks since other immunosuppressives, e.g., cyclophosphamide, azathioprine, cyclosporine --Patient Characteristics-- * Renal: Creatinine less than 1.5 mg/dL * Cardiovascular: No hypovolemia; no infarction; no vasculitis; no other major systemic cardiovascular illness * Pulmonary: No major respiratory illness * Other: No infection, including hepatitis or human immunodeficiency virus; no recent intravenous drug abuse; no high-risk sexual behavior; no cardiac, cerebrovascular, or autonomic dysfunction that would increase risk of hypotension; no other major systemic illness that would preclude protocol therapy; no pregnant or nursing women; negative serum pregnancy test required of fertile women; effective contraception required