Sensory neuronopathy and small cell lung cancer: antineuronal antibody reacting with neuroblastoma cells.

The anti-Hu antibody is associated with a paraneoplastic subacute sensory neuronopathy (SSN) described in cases of small cell lung cancer (SCLC). The Hu antigen is a pan-neuronal nuclear antigen with a molecular weight of 35-40 kDa. In this study we demonstrated the presence of the paraneoplastic Hu antigen in different neuroblastoma cell lines. We showed that by indirect immunocytochemistry the serum of patients with SSN and SCLC reacts with the nuclei of neuroblastoma cell lines SKN-SH and LAN-1. Western blot analysis of nuclear extracts from neuroblastoma cell lines SKN-SH, IMR-32 and LAN-1 confirmed the presence of the Hu antigen in these neuroblastoma cell lines. By comparing the immunocytochemical method and the Western blot analysis we were able to determine that the Western blot analysis was a more sensitive test. Screening of the sera of a large population (a total of 122 patients with SCLC, 17 with paraneoplastic disorders as well as 121 controls with other neurological disorders) was performed and showed all 5 of the patients with SSN and SCLC to be positive for the anti-Hu antibody, whereas only 11 of the 122 SCLC patients and none of the controls were positive, thereby suggesting that this test has a very high degree of sensitivity.