[Recent topics of chronic inflammatory demyelinating polyneuropathy]

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired, immune-mediated polyradiculoneuropathy. The American Academy of Neurology criteria has been used widely in diagnoses, and has generated clinical and pathological information. Recently, the EFNS/PNS criteria revised the concept of conventional "typical CIDP" and "atypical CIDP", with atypical CIDP including five phenotypes: DADS (distal acquired demyelinating symmetric), MADSAM (multifocal acquired demyelinating sensory and motor), focal, pure motor, and pure sensory neuropathy. However, the concepts of pure sensory, pure motor, and "idiopathic" DADS neuropathy do not have sufficient pathogenic support. MADSAM neuropathy shows significant hypertrophic nerve roots and/or plexuses. Since the characteristic multifocal distribution should correspond to the hypertrophic distribution, MADSAM or "hypertrophic CIDP" may be the promising phenotype of atypical CIDP. Clinical trials indicate that IVIg is more effective in a short time than corticosteroids for the treatment of CIDP, although corticosteroids maintain a longer immune suppression than IVIg. These results suggest that "hybrid therapies", IVIg induction and corticosteroid maintenance, may be effective. A recent study showed that IVIg stabilizes axonal potentials and axonal membranes, and our group showed that juxtaparanodal TAG-1 may be associated with IVIg responsiveness. Although CIDP is a demyelinating disease, the involvement of axon or axon-myelin interactions should be considered.