We report a 68-year-old woman who presented with posterior uveitis, cerebellar ataxia, dysautonomia, peripheral neuropathy and undifferentiated carcinoma. Autopsy showed slight brain inflammatory changes and severe Purkinje cell degeneration. By immunocytochemistry, the serum and CSF contained antibodies that reacted with the cytoplasm of cells in the brain and retina of rat. Some neurons and glial cells were stained. However, the most labelled cells were immature cells of the subventricular layers of the dentate gyrus, olfactory bulb and lateral ventricles. In rat retina, the plexiform layers and cells of the inner granular layer were stained. E15 rat embryo showed diffuse staining of post-mitotic cells and process in the central and peripheral nervous system. With the patient's IgG, various bands of 45, 60, 70 and 135 kDa apparent molecular weight were demonstrated on immunoblots of adult human, adult and E15 embryonic rat brain and rat and bovine retina. Eluates of tissue bound IgG labelled the same bands.