Double filtration plasmapheresis in myasthenia gravis - analysis of clinical efficacy and prognostic parameters

Objectives - The aim of this study was to evaluate the efficacy of double f iltration plasmapheresis (DFP) in the treatment of patients with myasthenia gravis (MG) and to analyze the possible prognostic factors related to resp onsiveness to DFP. Materials and methods - We treated 45 MG patients. 26 wo men and 19 men aged 21-72 years, with DFP for 5 consecutive sessions. All w ere affected by severe generalized or respiratory weakness with an Osserman 's classification of group 2 or 3 and had not responded to previous treatme nts. Results - Thirty-eight out of 45 patients (84%) achieved significant i mprovements after DFP. The baseline MG score and removal rate for immunoglo bulin G (IgG) were significantly higher in the patients with good response than in the other response groups. Poor responders were more likely to have thymoma and a longer interval among sessions of DFP. Better response in pa tients with age at onset of less than 40 years was associated with higher M G score. Serum concentration of all proteins tested fell as follows (mean /- SD): IgM, 88 +/- 7%; IgA, 71 +/- 11%; IgG, 59% +/- 14%; globulin, 52 + 1 1%, AchRAb, 47 +/- 14%; and albumin, 27 +/- 10%. All the patients tolerated plasmapheresis well except for 2.2% who experienced hypotension. Conclusio n - In this study, DFP was effective and safe in the treatment of patients with severe generalized MG. The factors correlating with the better clinica l response were high MG score, a thymic pathology of non-thymoma, daily aph eresis, young age at onset, and high removal rate for IgG.