P0 protein is a target antigen in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is widely regarded as an autoimmune disorder, although the autoantigen remains unknow n. In this study, the sera of 21 CIDP patients were examined by immunofluor escence for antimyelin activity and by Western blotting for binding to myel in proteins. Six sera contained anti-P0 immunoglobulin G antibodies, and fo ur of these caused conduction block and demyelination following intraneural injection in experimental animals. Absorption with PO protein eliminated t he demyelinating activity. These results show that PO is an autoantigen in some patients with CIDP. Since PO possesses powerful adhesion properties an d is largely responsible for myelin compaction, the demonstration of demyel ination by human anti-P0 antibodies provides new insight into this importan t and common immunopathological process.