CHRONIC DYSIMMUNE DEMYELINATING POLYNEUROPATHY - A CLINICAL AND ELECTROPHYSIOLOGICAL STUDY OF 93 PATIENTS

Objectives-To identify clinical, electrophysiological, and immunologic al characteristics of chronic immune demyelinating polyneuropathy to d efine for each group the appropriate therapeutic strategies. Methods-T he clinical and electrophysiological data and the response to treatmen t of 93 patients with an acquired chronic dysimmune demyelinating poly neuropathy (CDDP) studied over a period of 10 years were reviewed. Two groups were identified: group 1, comprising 64 patients with an idiop athic CDDP, of whom 13 had serum monoclonal or polyclonal gammopathy w ithout detectable antibodies directed against the ''myelin associated glycoprotein)) (MAG), and group 2, comprising 29 patients with an IgM monoclonal gammopathy of undetermined significance (MGUS) with antibod ies binding to the MAG. Results-Group 1 patients had either a progress ive or relapsing course. The relapsing course had more pronounced dist al slowing of motor conduction velocity. In group 1, there were no sig nificant clinical or electrophysiological differences between patients with or without gammopathy. Patients with anti-MAG antibody (group 2) differed significantly from group 1 patients, especially on the basis of electrophysiological results, They had a more pronounced slowing o f peroneal motor nerve conduction velocity, a lower frequency of condu ction block, and a distal accentuation of conduction slowing, distingu ishing them from those with idiopathic CDDP, Charcot-Marie-Tooth polyn europathy type 1A, and control subjects. Conclusion-The idiopathic CDD P group is heterogeneous with probably different subgroups. Patients w ith IgM MGUS polyneuropathy and anti-MAG antibodies have characteristi cs which distinguish them significantly from other CDDP and suggest di fferent immune mechanisms and responses to treatment.