Circulating antineuronal antibodies reach neurons in vivo: an autopsy study.

In serum and cerebrospinal fluid of 6 out of 15 patients with small cell lung cancer circulating antineuronal antibodies could be detected by indirect immunofluorescence. None of the patients showed signs of a neurological paraneoplastic syndrome, usually associated with the presence of these antibodies. On sections of frontal brain, cerebellum, dorsal root ganglia and peripheral nerve, obtained at autopsy, a direct immunofluorescence test was performed. Only in antibody-positive individuals were membrane-bound immunoglobulin deposits detected on neurons of dorsal root ganglia and Purkinje cells. The present study showed that circulating antineuronal antibodies reach the central and peripheral nervous system in vivo. These findings support the theory that these antibodies might be directly involved in the pathogenesis of neurological paraneoplastic syndromes.