[A case of intravenous immunoglobulin-dependent chronic inflammatory demyelinating polyneuropathy of pure motor form responsive to mycophenolate mofetil therapy].

This report concerns a case of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with frequent treatment-dependent relapses. A 75-year-old male presented with a 2-month history of progressive weakness of the limbs with no sensory symptoms. Neurological examination revealed normal cranial nerves, MRC grade 4 power in the proximal and distal muscles of the limbs, and generalized areflexia. However, the sensory examination results, serum immunoelectrophoresis, anti-HIV antibody, and vitamins B1 and B12 levels were normal. Cervical MR imaging was unremarkable. Cerebrospinal fluid showed albuminocytologic dissociation. Nerve conduction studies demonstrated prolonged distal latencies in the bilateral median nerves and left ulnar nerve. Treatment with intravenous immunoglobulin (IVIg) infusion resulted in a marked improvement. Thereafter, the patient had been treated with repeated IVIg to maintain motor function. Subsequently, the patient fulfilled the EFNS/PNS diagnostic criteria for pure motor form of definite CIDP. Treatment with ciclosporin with the plasma trough level of 60-150 ng/ml reduced the frequency of IVIg. However, renal function began to deteriorate 94 months after the initiation of ciclosporin. The calcineurin inhibitor was replaced with mycophenolate mofetil 1,500 mg, which significantly increased the interval between infusions without further renal impairment. Therefore, mycophenolate may represent an effective alternative treatment for some IVIg-dependent CIDP patients.