Comparison of plasmapheresis and intravenous immunoglobulin as maintenance therapies for juvenile myasthenia gravis

IMPORTANCE Juvenile myasthenia gravis (MG) is a relatively rare autoimmune disorder. The comparative efficacy of plasmapheresis (PLEX) vs immunoglobulin as maintenance therapy is unclear for this childhood disease. OBJECTIVE To determine whether PLEX or intravenous immunoglobulin (IVIG) therapy is more effective as maintenance therapy in this disease. DESIGN, SETTING, AND PARTICIPANTS This retrospective analysis over a 33-year period involved 54 children and adolescents with juvenile MG at a specialized neuromuscular clinic and electromyography laboratory at a tertiary care academic pediatric hospital. INTERVENTIONS Plasmapheresis and IVIG. MAIN OUTCOMES AND MEASURES Response to treatmentwas measured by both improvement in objective physical examination findings and the patients' reported improvement in symptoms and functional abilities. RESULTS Subjective and objective outcomes correlated well. Both PLEX and IVIG had high response rates. Of the 27 patients with generalized juvenile MG receiving PLEX, IVIG, or both treatments, 7 of 7 patients treated with PLEX alone responded, 5 of 10 patients treated with IVIG alone responded, and 9 of 10 patients who received both responded. There was a significant difference in response rates between patients who received PLEX vs IVIG (P = .04). The youngest age at which PLEX was initiated via peripheral venous access was 9 years, while the youngest child who received IVIG was 9 months old. Thymectomy was performed in 17 children, of whom 11 experienced significant postoperative improvement. CONCLUSIONS AND RELEVANCE This study provides class III evidence that PLEX and IVIG both have high response rates as maintenance therapies and are reasonable therapeutic options for juvenile MG. Plasmapheresis may have a more consistent response rate than IVIG in this setting. These findings will provide some guidance regarding the approach to therapy for juvenile MG, especially as the results differ somewhat from those of studies focusing on adult MG.