Autoimmune pathogenesis of paraneoplastic neurological syndromes.

"Remote effects" of cancer on the nervous system (paraneoplastic syndromes) are disorders of the nervous system of unknown cause that occur almost exclusively, or with greatly increased frequency, in patients with identifiable or occult cancer. There are several hypotheses concerning the pathogenesis of these rare disorders. One hypothesis is that the underlying tumor and portions of the nervous system share antigens and that an autoimmune response generated against the tumor causes the nervous system disorder. Evidence supporting this hypothesis includes the ability to transmit the Lambert-Eaton Syndrome (a paraneoplastic syndrome involving the neuromuscular junction) to experimental animals by infusing IgG from patients with the disorder, the presence of autoantibodies against Purkinje cell neurons in some patients with paraneoplastic cerebellar degeneration, and the presence of autoantibodies against many neurons in patients with sensory neuronopathy and encephalomyelitis. Other evidence supporting the hypothesis is presented in this review.