Polyneuropathy that is associated with monoclonal gammopathy of undetermined significance (MGUS) similar to chronic inflammatory demyelinating polyneuropathy (CIDP) has been reported before, whereas a connection to acute inflammatory demyelinating polyneuropathy (AIDP) has not been. A 52 year-old man was presented with ascending paralysis beginning 1 day ago. Neurological examinations showed facial diplegia and decreased motor power and deep tendon reflexes in all extremities. On electrophysiologic study, sensorimotor polyneuropathy was observed. Proteinand immunoelectrophoresis revealed IgA
