Comparison of Plasmapheresis and Intravenous Immunoglobulin as Maintenance Therapies for Juvenile Myasthenia Gravis

Abstract

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 treatment was 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.

Clinical features and evolution of juvenile myasthenia gravis in a French cohort

“…In addition, IVIg is an effective treatment during exacerbations or as maintenance treatment post‐exacerbation to stabilize disease, and its efficacy is well established in children . A recent study comparing plasmapheresis and IVIg as maintenance therapies in JMG shows that both are effective, but there is a more consistent response rate in patients treated with plasmapheresis . Immunoadsorption is an extracorporeal elimination therapy with selective antibody filtration and has shown good efficacy in adults, in some children, and in 1 patient in our study.…”

Rituximab treatment of myasthenia gravis: A systematic review

“…Standard initial treatment of MG usually employs corticosteroids; in refractory cases, or those exhibiting steroid‐induced adverse effects, add‐on therapy with cyclosporine, azathioprine, cyclophosphamide, mycophenolate mofetil, methotrexate, or tacrolimus may be helpful . Intravenous human immunoglobulin (IVIg) and plasma exchange (PLEX) are used successfully in standard practice for acute exacerbations, as maintenance therapy, or preoperatively before thymectomy . Most recently, the efficacy of extended transsternal thymectomy was demonstrated in a controlled trial in non‐thymomatous generalized AChR MG .…”

Systematic review of immunoglobulin use in paediatric neurological and neurodevelopmental disorders

“…Ten studies evaluated the efficacy of IVIG in paediatric neuroinflammatory conditions of interest (Table SIIb). Three series ( n =67) of patients with generalized and ocular myasthenia gravis found response to treatment in 74% ( n =20 out of 27) with IVIG with or without corticosteroids, 91% ( n =10 out of 11) with plasma exchange and IVIG, and 100% ( n =7 out of 7) with plasma exchange alone . Thymectomy was required in 37% ( n =25 out of 67).…”