Presence of paraneoplastic antibodies in non-carcinomatous patients with neurological involvements of unknown cause.

BACKGROUND: Paraneoplastic antibodies (PAs) play a crucial role in the diagnostic approach of paraneoplastic neurological syndrome (PNS). We clarified the frequency and the clinical profile of PA-positive non-carcinomatous patients with neurological involvements of unknown cause.
METHODS: PAs were analyzed in sera of 222 consecutive non-carcinomatous patients (122 men and 100 women) defined as acute or subacute onset of unknown-causative symptoms involving the neuromuscular junction, the central and/or the peripheral nervous system between 2006 and 2009. PAs contained antineuronal nuclear autoantibody type 1, 2, 3, Purkinje cell cytoplasmic autoantibody type 1, 2, anti-Tr, amphiphysin, CRMP-5, P/Q-type, N-type voltage-gated calcium channels (VGCC), voltage-gated potassium channel complex (VGKCC) and neuronal acetylcholine receptor (nAChR) antibodies. PA-seropositive patients received detailed examination of carcinoma in the whole body for the following 2 years.
RESULTS: Nine patients were PA-positive. VGKCC antibodies were found in four patients, P/Q-type VGCC antibodies in two, N-type VGCC antibodies in two and nAChR antibodies in one. Neurological features revealed limbic encephalitis in four patients, sensorimotor neuropathy in three and Lambert-Eaton myasthenic syndrome in two. One year later, 2 patients developed myelodysplastic syndrome and lung adenocarcinoma (one patient each).
CONCLUSION: We conclude that PA-seropositive frequency is 4.1% in non-carcinomatous neurological patients at examination. VGKCC, P/Q-type and N-type VGCC, and nAChR antibodies have benefits for screening non-carcinomatous PNS patients with acute or subacute neurological deficits of unknown cause.