Plasma exchange therapy inhibited the progression of anti-MAG antibody-associated polyneuropathy

The patient was a 75-year-old male with slowly progressive numbness and weakness in his distal limbs, who had been diagnosed with anti-MAG antibody-associated polyneuropathy (MAGN) at another hospital. Although rituximab, intravenous high-dose immunoglobulins, and methyl prednisolone were administered, the neuropathy progressed. Only plasma exchange alleviated the patient’s symptoms. His state was maintained by performing plasma exchange every 2 months for 4 years (total: 26 courses). Based on RCT results, rituximab is becoming the main treatment for MAGN, but in one-third of cases it is ineffective or worse; therefore, alternative treatments are needed. While some studies have found that plasma exchange has short-term effects against MAGN, no previous studies have shown that it has long-term effects against the condition. In our patient, long-term plasma exchange was effective against MAGN, suggesting that plasma exchange suppresses the progression of MAGN and is a useful maintenance therapy for the condition.