Intravenous immunoglobulin therapy in paraneoplastic neurological syndromes.

Combining clinical and immunological information, a neurological syndrome can now be diagnosed as a "definite" or "possible" paraneoplastic syndrome according to the newly suggested diagnostic criteria of the PNS Euronetwork. Differentiated diagnosis of a paraneoplastic syndrome is essential for differential therapy in patients. According to the response to IVIG therapy, paraneoplastic disorders may be subgrouped in group A, a clinical response is the rule (prototype Lambert-Eaton myasthenic syndrome), and in group B, IVIG may be helpful in single patients and is indicated in specific clinical settings (prototype anti-Hu associated neurological syndromes). The mode of action of IVIG may range from direct anti-idiotype effect to indirect effects on the cellular part of the pathogenesis of paraneoplastic syndromes. Due to the therapeutic relevance, it is therefore important to diagnose a PND as early as possible, and start immunotherapy including IVIG immediately.