Diagnostic value of cerebrospinal fluid anti-myelin basic protein in patients with multiple sclerosis.

Prevalence and titer of total, free, and bound cerebrospinal fluid anti-myelin basic protein (MBP) antibodies as well as free/bound ratios were determined in four groups of patients with multiple sclerosis (MS) and three groups of controls. All patients with clinically active MS have elevated levels of total anti-MBP, which may be present in either free or bound form. Patients whose disease is in remission have undetectable anti-MBP levels, and some patients with clinically stable disease with residual disability may have detectable antibody titers. Chronically progressive MS is usually associated with high levels of antibody in the bound rather than the free form, resulting in a low or normal free/bound ratio. In contrast, MS exacerbations are characterized by relatively high levels of free anti-MBP in the cerebrospinal fluid, resulting in a high free/bound antibody ratio. Bound anti-MBP was also detected in elevated levels in 1 patient with subacute sclerosing panencephalitis and 2 of 8 patients with postinfectious encephalomyelitis. Although elevated levels of cerebrospinal fluid anti-MBP are not specific for MS, they are strongly associated with disease activity and may be involved in the pathogenesis of demyelination in patients with MS.