NEUROLOGIC PARANEOPLASTIC SYNDROMES

Several neurologic paraneoplastic disorders are believed to be caused by an autoimmune reaction against antigen(s) co-expressed by tumour ce lls and neurons. Of the paraneoplastic syndromes, the evidence for an autoimmune etiology is strongest for the Lambert-Eaton myasthenic synd rome, in which autoantibodies downregulate voltage-gated calcium chann els at the presynaptic nerve terminal. For other syndromes, including cerebellar degeneration, multifocal encephalomyelitis, sensory neurono pathy, limbic encephalitis, opsoclonus-myoclonus, stiff person syndrom e, and retinal degeneration, the autoimmune theory is supported by the presence of specific antineuronal antibodies. These antibodies serve as a useful diagnostic tool, but their actual role in causing neuronal injury and clinical disease remains unclear. Further understanding of immunopathogenesis awaits successful experimental models. Among diffe rent syndromes, a varied proportion of patients shows neurologic impro vement with immunosuppressive treatments; it is likely that many patie nts have already suffered irreversible neuronal injury at the time of diagnosis. (C) 1998 Elsevier Science B.V.