Anti-MAG antibodies in 202 patients: clinicopathological and therapeutic features

Objective To assess the clinicopathological and therapeutic features of patients with low (≥1000 to Methods We retrospectively and prospectively analysed standardised report forms and medical records of 202 patients from 14 neuromuscular centres. Results Mean age at onset and mean time between symptom onset to last follow-up were respectively 62.6 years (25–91.4) and 8.4 years (0.3–33.3). Anti-MAG antibody titres at diagnosis were low, medium or high in 11%, 51% and 38% of patients. Patients presented with monoclonal gammopathyof undetermined significancein 68% of cases. About 17% of patients presented with ‘atypical’ clinical phenotype independently of anti-MAG titres, including acute or chronic sensorimotor polyradiculoneuropathies(12.4%), and asymmetric or multifocal neuropathy (3%). At the most severe disease stage, 22.4% of patients were significantly disabled. Seventy-eight per cent of patients received immunotherapies. Transient clinical worsening was observed in 12% of patients treated with rituximab(11/92). Stabilisation after rituximabtreatment during the 7–12-month follow-up period was observed in 29% of patients. Clinical response to rituximabduring the 6-month and/or 7–12-month follow-up period was observed in 31.5% of patients and correlated with anti-MAG titre ≥10 000 BTU. Conclusion Our study highlights the extended clinical spectrum of patients with anti-MAG neuropathy, which appears unrelated to antibody titre. Besides, it may also suggest beneficial useof rituximabin the early phase of anti-MAG neuropathy.