The anti-MAG IgM antibody plays a pathogenic role by depositing within the myelin sheath. Randomized Controlled Trials using Rituximab in anti-MAG neuropathy have failed to demonstrate significant benefits, suggesting that greater efficacy in reducing IgM monoclonal levels is needed, as achieved through combined therapy in the IELSG-19 trial.

We conducted a retrospective cohort study, describing the clinical, electrophysiological, and biological characteristics at diagnosis, during the 2 years after combined treatment and throughout long-term follow up. Various clinical outcomes were defined in order to analyzed treatment effectiveness. 

Fifteen patients with anti-MAG neuropathy were followed in our cohort. The median follow-up time was 3.1 years [2.3 -13.9] with a long-term follow-up data available for 10 patients (76.9%). The median age at the onset was 62 years [42 -82]. Eleven patients (73.3%) received biotherapy combining Rituximab with Chlorambucil while 2 patients (13.3%) received Rituximab with Cyclophosphamide.  During the first 2 years of follow-up after treatment, 7/10 patients (70%) showed clinical improvement, 2/10 experienced deterioration, and 1 remained stable. Over long-term follow-up, 3/10 patients remained stable, 5/10 showed neurological deterioration due in 3/10 cases to slow axonal loss in lower limbs and in 2/10 patients to relapse of neuropathy and hematologic disease leading to retreatment with positive outcome. One patient was retreated due to lack of hematological response. Two patients (15.4%) died, one from cancer within the first year after diagnosis and another from a pulmonary infection related to a long-standing lung condition.