A variant of the anti-Purkinje cell antibody in a patient with paraneoplastic cerebellar degeneration.

An anti-Purkinje cell antibody was found in the serum and CSF of a man with adenocarcinoma of the lung and paraneoplastic cerebellar degeneration (PCD). This antibody differed from the autoantibodies found in patients with gynecologic cancer and PCD in that it produced a different pattern of Purkinje cell cytoplasmic staining, did not react with PCD antigens in Purkinje cell Western blots, and the antigen had a different species distribution. Unlike the antinuclear antibody found in patients with PCD and small-cell lung carcinoma, the antigen was restricted to the cytoplasm of Purkinje cells. If autoantibodies are important in the pathogenesis of PCD, this case illustrates that they can recognize different antigenic epitopes in the nervous system, but cause similar clinicopathologic syndromes.