Efficacy and safety of double-filtration plasmapheresis treatment of myasthenia gravis: A systematic review and meta-analysis

OBJECTIVES

To evaluate the efficacy of double-filtration plasmapheresis (DFPP) treatment of myasthenia gravis (MG) through a systematic review and meta-analysis.

METHODS

PubMed, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), and Wanfang databases were searched for randomized controlled trials (RCTs) and clinical controlled trials (CCTs) on DFPP for MG from database establishment to June 2019. Two researchers independently screened the articles, extracted the data, and cross checked the results. RevMan 5.3 was used for statistical analyses.

RESULTS

Seven RCTs and 2 CCTs were found comprising 329 patients. The results showed that clinical MG remission rate after DFPP treatment was significantly higher (OR = 4.33; 95% confidence interval [CI], 1.97-9.53; P < .001) and the serum levels of antititin antibody was significantly decreased (standardized mean difference [SMD] = 9.30; 95% CI, 7.51-11.08; P < .001). In addition, the quantitative MG (QMG) score, hospital stay and time to remission of MG symptoms, and acetylcholine receptor antibody (AchRAb) decreased in the DFPP treatment group; however, these outcomes had high heterogeneity among the studies. Only one study has reported on the adverse effects, including hypotension and hematoma.

CONCLUSION

This meta-analysis suggests that DFPP can be recommended for the short-term mitigation of MG. Because our review was limited by the quantity and quality of the included studies, the above conclusions should be verified by additional high-quality studies.

Predicting the course of myasthenic weakness following double filtration plasmapheresis

OBJECTIVE

To evaluate the clinical course of patients with myasthenia gravis (MG) up to 3 months after double filtration plasmapheresis (DFP).

MATERIAL AND METHODS

We recorded the MG score and measured the level of acetylcholine receptor antibody (AchRAb) at baseline and day 1 (D1), week 1 (W1), 1 month (M1), 2 (M2) and 3 months (M3) after DFP in 16 MG patients. Based on the difference in score during follow-up, we divided our patients into clinical improvement (CI) and clinical worsening (CW) groups.

RESULTS

The MG score decreased in all courses from a mean of 8.1 at baseline to 5.6 at D1, and to 4.7, 4.0, 3.8, and 3.7 at W1, M1, M2, and M3, respectively. In the CW group, AchRAb levels were significantly higher at M1 (P = 0.022). The AchRAb level at W1 correlated significantly with the MG score at M3 (P = 0.027) and the changes of MG score from W1 to M1 (P = 0.029). The ratio of AchRAb levels of M1 to W1 correlated well with MG score at W1 (P = 0.032), at M3 (P = 0.001), and the changes of MG score from W1 to M1 (P = 0.004).

CONCLUSION

Excessive rebounds of AchRAb level at W1 may suggest clinical worsening and further increases in AchRAb level at M1 predict poorer outcome after DFP.

Double filtration plasmapheresis in the treatment of myasthenic crisis--analysis of prognostic factors and efficacy

OBJECTIVES

To examine the prognostic factors and outcome of myasthenia gravis (MG) patients in crisis with double filtration plasmapheresis (DFP) treatment.

MATERIAL AND METHODS

A total of 15 patients experienced 20 episodes of crisis during the study period. Plasmapheresis was carried out using a double filtration

METHOD

Demographic information, clinical features of crisis, and associated complications were analyzed.

RESULTS

The median duration of crisis was 9 days. Chest infection was the most common precipitant of crisis. Twelve out of the 20 episodes (60%) responded well to DFP and mechanical ventilation was discontinued after the third session of DFP in 8 of them. Three significant predictors for prolonged crisis were shorter intervals between the onset of MG and the first crisis (P=0.04), higher serum bicarbonate levels at baseline (P=0.03) and the thymic pathology of thymoma (P=0.03).

CONCLUSION

DFP can ameliorate the profound weakness in crisis and seems to be a rational therapy for patients with myasthenic crisis.

Optimal volume of processed plasma and total number of selective plasmapheresis sessions in the treatment of patients with severe generalized myasthenia gravis

The selection of the technical parameters of plasmapheresis in the treatment of patients with MG varies widely due to the lack of sufficient data from controlled studies to standardize the plasmapheresis procedure. Eight myasthenia gravis (MG) patients (Osserman IIb and III) received either immunoadsorption plasmapheresis (IA) with a IM-TR 350 (Asahi Medical Co., Tokyo, Japan) or double filtration plasmapheresis (DF) with a Cascadeflo AC-1770, with four in each group. A Plasmaflo AP 05 W (Asahi Medical Co., Tokyo, Japan) was used as the plasma separator in both groups. Each course of treatment consisted of five sessions of aphereses on alternate days. Plasma was sampled before and after passing through the column. Samples of plasma were analyzed for acetylcholine receptor antibody (AchRAb) at the start of plasmapheresis and sequentially after every 0.5 L of plasma treated. The IA method cleared significantly more AchRAb during the initial treatment of 1. 5 L of plasma than the DF method, especially in the initial 1 L (P < 0.01). The column saturated after treatment of 1.5 to 2 L of plasma. It is known that over-saturation of column may release the already adsorbed/filtrated antibodies. Longitudinal analysis on the serological changes during the five sessions revealed that the clearance obtained using the IA method was significantly higher and more sustained after the first session of treatment compared to the DF method (P < 0.05). The titers of AchRAb were also noted to rise after the fourth session. These results suggest that 2 L of processed volume is optimal in terms of the functional capacity of a plasmapheresis column in either IA or DF methods, and that a total of four sessions of treatment in one course may provide optimal elimination of AchRAb.

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 filtration plasmapheresis (DFP) in the treatment of patients with myasthenia gravis (MG) and to analyze the possible prognostic factors related to responsiveness to DFP.

MATERIALS AND METHODS

We treated 45 MG patients, 26 women and 19 men aged 21-72 years, with DFP for 5 consecutive sessions. All were affected by severe generalized or respiratory weakness with an Osserman's classification of group 2 or 3 and had not responded to previous treatments.

RESULTS

Thirty-eight out of 45 patients (84%) achieved significant improvements after DFP. The baseline MG score and removal rate for immunoglobulin 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 patients with age at onset of less than 40 years was associated with higher MG score. Serum concentration of all proteins tested fell as follows (mean +/- SD): IgM, 88+/-7%; IgA, 71+/-11%; IgG, 59+/-14%; globulin, 52+/-11%; AchRAb, 47+/-14%; and albumin, 27+/-10%. All the patients tolerated plasmapheresis well except for 2.2% who experienced hypotension.

CONCLUSION

In this study, DFP was effective and safe in the treatment of patients with severe generalized MG. The factors correlating with the better clinical response were high MG score, a thymic pathology of non-thymoma, daily apheresis, young age at onset, and high removal rate for IgG.