Relapses After Treatment With Rituximab in a Patient With Multiple Sclerosis and Anti–Myelin-Associated Glycoprotein Polyneuropathy

OBJECTIVE: To describe the unique case of a patient with multiple sclerosis (MS) and anti-myelin-associated glycoprotein (MAG) polyneuropathy who developed MS relapses after treatment with rituximab. DESIGN: Case report. SETTING: Department of Neurosciences, Ophthalmology, and Genetics, University of Genova, Genova, Italy. Patient A 59-year-old man with an 18-year history of MS presented with an unusually rapid progression of paraparesis with hypopallesthesia and areflexia in 4 limbs. Neurophysiological and serological studies led to the diagnosis of anti-MAG polyneuropathy. Cerebrospinal fluid analysis disclosed the loss of oligoclonal IgG bands that were previously detected at MS onset. Intervention Rituximab was administered at a dosage of 375 mg/m(2)/wk for 4 weeks. Result The patient developed 2 corticosteroid-responsive MS relapses with improvement of the polyneuropathy. CONCLUSION: Rituximab can be effective in anti-MAG polyneuropathy but can possibly lead to unexpected consequences in individuals with MS.