Comparison between double-filtration plasmapheresis and immunoadsorption plasmapheresis in the treatment of patients with myasthenia gravis

Two techniques for plasmapheresis are used in the treatment of myasthenia g ravis (MG): immunoadsorption (IA) and double filtration (DF). This controll ed study evaluated the differences between these techniques in clinical eff ects and serological changes. Five patients with generalized MG (clinical s tates IIb and III) were enrolled; each patient received IA and DF plasmaphe resis on separate occasions. Immunosorba TR-350 with an affinity to acetylc holine receptor antibodies (AchRAb) was used for IA, while Evaflux 4A was u sed as the plasma fractionator for DF. Each course of treatment consisted o f five sessions of apheresis. MG score, titers of AchRAb, immunoglobulins ( Ig), and plasma biochemistry were assessed by blinded examiners before and immediately after the entire course of treatment. Both treatments effective ly ameliorated symptoms of MG. There were no significant changes in MG scor e between the two groups (IA vs. DF: 2.2 vs. 2.6, P > 0.5). IA had a higher clearance rate of AchRAb than DF (66% vs. 54%. P < 0.05). while DF removed more IgA (72% vs. 21%, P < 0.05) and IgM (89% vs. 57%, P < 0.01) than did IA. Although IA removed AchRAb more effectively than DF the clinical effect s between these two treatments were similar. The titers of AchRAb cannot re flect the clinical severity. Some circulating factors other than AchRAb may contribute to the pathogenesis of MG.