A point of view: The need to identify an antigen in psyconeuroimmunological disorders.

Several lines of evidence support a mutual relationship between the nervous system and the immune system. Therefore, it is not surprising that some neuropsychiatric disorders are also characterized by immune abnormalities. In patients with phobic disorders and in patients with migraine without aura some common immune abnormalities have been detected and, in particular, natural immunity deficits, exaggerated release of proinflammatory cytokines and circulating bacterial endotoxins have been found. In other neurological disease, some etiologic factors have been detected as in the case of Guillain-Barrè syndrome in which molecular mimicry between Campylobacter jejuni endotoxin and GM1 ganglioside may cause an acute inflammatory polyneuropathy. On the other hand, attempts to identify an antigen have been made in patients with Alzheimer's disease and schizophrenia. Finally, the chronic fatigue syndrome, an old illness in search for an antigen, risk factors and precipitating agents have been described but evidence for a specific antigen is still lacking.