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

Changes in Water Properties in Human Tissue after Double Filtration Plasmapheresis-A Case Study

Double-filtration plasmapheresis (DFPP) is a blood cleaning technique that enables the removal of unwanted substances from the blood. In our case study, we performed near-infrared (NIR) spectroscopy measurements on the human hand tissue before and after a specific DFPP treatment (INUSpheresis with a TKM58 filter), along with NIR measurements of the substances extracted via DFPP (eluate). The spectral data were analyzed using the aquaphotomics approach. The analysis showed that the water properties in the tissue change after DFPP treatment, i.e., an increase in small water clusters, free water molecules and a decrease in hydroxylated water as well as superoxide in hydration shells was noted. The opposite effect was observed in the eluates of both DFPP treatments. Our study is the first that documents changes in water spectral properties after DFPP treatments in human tissue. The changes in tissue water demonstrated by our case study suggest that the positive physiological effects of DFPP in general, and of INUSpheresis with the TKM58 filter in particular, may be associated with improvements in water quality in blood and tissues.

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.

Safety and efficacy of plasma exchange via direct femoral vein puncture in autoimmune blistering diseases

Plasma exchange (PE) is performed for patients with autoimmune blistering diseases by using multiple vascular access routes. We retrospectively examined the safety and the efficacy of PE using direct femoral vein puncture (FVP) technique, by comparing with that using double-lumen catheter (DLC). The troubles related to vascular route, such as catheter occlusion, insufficient blood flow and hematoma, were not different between the FVP group (4.6%) and the DLC group (6.7%), whereas access-related infections occurred more frequently in the DLC group (6.7%) than the FVP group (0.4%). Regarding the efficacy, the removal rate of autoantibodies in PE using the FVP technique was similar or lower, as compared with that using the DLC. These results suggest that PE with the FVP technique is able to be performed safely in patients with autoimmune blistering diseases, although the removal of autoantibodies is not superior to that using the DLC.

Removal Dynamics of Autoantibodies, Immunoglobulins, and Coagulation Factors by Selective Plasma Exchange on Three Consecutive Days

Selective plasma exchange has been shown to be effective in various diseases, but no studies have assessed the benefits of daily treatment. We aimed to investigate the removal dynamics of immunoglobulins, fibrinogen, and factor XIII on three consecutive days in three patients. For mean processed plasma volumes of 1.06 × plasma volume, reductions of 79.6%, 49.3%, and 8.6% were seen for immunoglobulins G, A, and M, respectively. The reductions for fibrinogen and factor XIII were 18.4% and 13.0%, respectively. Removal dynamics were similar for immunoglobulin G-related autoantibodies and immunoglobulin G when using daily selective plasma exchange. Moreover, daily use effectively removed the immunoglobulin G while retaining the coagulation factors. When disease-specific autoantibodies are limited to immunoglobulin G, daily selective plasma exchange may be a useful and safe method of intensive induction treatment for plasmapheresis. However, further study is required in larger cohorts to confirm these findings.

Autoimmune myasthenia gravis: emerging clinical and biological heterogeneity

Acquired myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction in which patients experience fluctuating skeletal muscle weakness that often affects selected muscle groups preferentially. The target of the autoimmune attack in most cases is the skeletal muscle acetylcholine receptor (AChR), but in others, non-AChR components of the neuromuscular junction, such as the muscle-specific receptor tyrosine kinase, are targeted. The pathophysiological result is muscle endplate dysfunction and consequent fatigable muscle weakness. Clinical presentations vary substantially, both for anti-AChR positive and negative MG, and accurate diagnosis and selection of effective treatment depends on recognition of less typical as well as classic disease phenotypes. Accumulating evidence suggests that clinical MG subgroups might respond differently to treatment. In this Review, we provide current information about the epidemiology, immunopathogenesis, clinical presentations, diagnosis, and treatment of MG, including emerging therapeutic strategies.

A Controlled Study of Double Filtration Plasmapheresis in the Treatment of Active Rheumatoid Arthritis

BACKGROUND

Double-filtration plasmapheresis with a plasma fractionator pore size of 20 nm should selectively remove large molecular weight substances like rheumatoid factor and IgM. This was proposed to be more likely to be helpful for rheumatoid arthritis than standard plasma exchange.

OBJECTIVE

To evaluate the efficacy of double-filtration plasmapheresis (DFPP) in the treatment of patients with active rheumatoid arthritis.

METHODS

Eighty-two patients were randomly assigned, 42 to the DFPP group and 40 to the no-DFPP group. All patients received sulfasalazine (0.75 g 3 times daily) plus methotrexate (10 mg orally once weekly). All patients had been on stable doses for more than 3 months. DFPP was performed once a week for 2 to 3 sessions. A total of 121 plasmapheresis procedures were performed in 42 patients. Control patients did not receive sham DFPP. The efficacy measures recorded 1 day after the final treatment and every month in follow-up for 4 to 22 months included the American College of Rheumatology (ACR) 20%, 50%, and 70% improvement criteria (ACR20, ACR50, and ACR70), the Health Assessment Questionnaire estimate of disability and the disease activity index.

RESULTS

Patients in the DFPP group had ACR20, ACR 50, and ACR70 improvements immediately after the last treatment of 100%, 92.9%, and 81.0%, when compared with the patients in no-DFPP group 17.5%, 0%, and 0% (P < 0.001). Significant change from baseline was observed in Health Assessment Questionnaire scores in the DFPP group, but not in the no-DFPP group (P < 0.001). The changes from baseline in the disease activity scores were significantly greater than in the no-DFPP group (P < 0.001). Improvements were maintained during follow-up of 7 to 22 months.

CONCLUSION

This open trial showed that DFPP therapy significantly altered the signs and symptoms of active rheumatoid arthritis. There were increases in physical function and improvement in quality of life. This is proposed as an approach that merits further investigation.

Therapeutic plasma exchange in the treatment of neuroimmunologic disorders: Review of 50 cases

Therapeutic plasma exchange (TPE) has been used for the treatment of neurologic diseases in which autoimmunity plays a major role. We reviewed the medical records of our patients who had consecutively been treated by TPE between January 1998 and June 2000. Neurological indications included myasthenia gravis (30 patients), multiple sclerosis attack (6 patients with remitting-relapsing course and 3 patients with secondary progressive course), Guillain-Barrè syndrome (6 patients), paraproteinemic neuropathy (2 patients), and chronic inflammatory demyelinating neuropathy (CIDP), transverse myelitis due to systemic lupus erythematosus, acute disseminated encephalomyelitis in one patient each. Continuous flow cell separators were used for TPE. TPE was generally given every other day for all of the patients and one plasma volume was exchanged for each cycle. Although the patients with secondary progressive multiple sclerosis (3 patients) and paraproteinemic neuropathy (2 patients) did not show any improvement after TPE, other patients' targeted neurological deficits were improved by TPE. During the TPE procedures, no patient had any morbidity or mortality, and the complications were mild and manageable such as hypotension, hypocalcemia and mild anemia; three patients had septicemia due to the venous catheter used for TPE. TPE is an effective treatment in neurologic diseases in which autoimmunity plays an important role in pathogenesis, and it is safe when performed in experienced centers.

Impact of Double-Filtration Plasmapheresis in Combination with Interferon and Ribavirin in Living Donor Liver Transplant Recipients with Hepatitis C

Double-filtration plasmapheresis (DFPP) selectively removes high molecular weight substances including hepatitis C virus (HCV). Four live donor liver transplantation (LDLT) recipients with HCV received combination therapy with low-dose interferon (IFN) and ribavirin with DFPP. Three patients underwent this therapy for prophylaxis of HCV recurrence, and one for treating fibrosing cholestatic hepatitis (FCH). The combination therapy and DFPP decreased HCV RNA levels to 8.2% +/- 2.9% and 0.7% +/- 0.5% by the 5th and 30th day of treatment, respectively. Three patients who underwent DFPP for prophylaxis showed no evidence of HCV recurrence for >1 year after treatment. The patient whose graft showed FCH, recovered dramatically after the DFPP treatment. DFPP appeared to be effective in reducing HCV viremia and preventing HCV recurrence in patients with high HCV RNA levels after LDLT. Moreover, it may become a rescue therapy for FCH in a liver transplant recipient with hepatitis C.

Clearance Studies During Subsequent Sessions of Double Filtration Plasmapheresis

To evaluate the optimal session of double filtration plasmapheresis (DFP) in terms of the maximal clearance rates for various serum substances, the laboratory parameters of 152 consecutive patients treated with different sessions of DFP following a standard protocol on an alternate-day basis was studied. Immunoglobulin M (IgM) and lipoprotein cholesterol had the most effective clearance by a minimum of two sessions of DFP treatment, and the clearance rates remained relatively constant despite the increase in the number of treatment sessions, while the clearance rates for other serum proteins increased steadily with further treatments. Using the clearance rate of the 2-session group as reference, the highest slopes for clearance of albumin, globulin, and triglyceride were found in the 4-session group, while the slopes for IgA and IgG were highest in the 5-session group. In conclusion, for the clearance of IgM and lipoprotein cholesterol, two sessions of DFP treatment are adequate. However, the best clearance of IgG and other globulins cannot be achieved until the fourth session of DFP treatment. Therefore, a minimum of 4 sessions of DFP treatment at 2-day intervals is needed for most immunological diseases.

Prethymectomy plasmapheresis in myasthenia gravis

Plasma exchange before thymectomy may decrease the time on mechanical ventilation (MV) and shorten the stay in the intensive care unit (ICU) for patients with myasthenia gravis (MG). This study evaluated the effects of prethymectomy plasmapheresis. A total of 29 myasthenic patients, 18 women and 11 men aged 20-73 years, were treated with double filtration plasmapheresis (DFP) for two to five consecutive sessions over a period between 2 and 21 days (mean 8.1 days) before transsternal thymectomy. Acetylcholine receptor antibody (AchRAb) titers, vital capacity (VC), maximal inspiratory pressure (Pimax), and MG score were measured before and after the course of DFP. Three outcome measures including duration of postoperative hospital stay, duration of ICU stay, and duration of MV were analyzed for correlation with clinical variables. The duration of MV ranged from 6 to 93 h, with a median of 21 h. The median ICU stay was one day and the median postoperative hospital stay was 10 days. A higher removal rate of AchRAb was associated with a shorter duration of ICU and postoperative hospital stay (P = 0.001 and 0.019, respectively). Postoperative hospital stay was strongly correlated with post-DFP Pimax (P = 0.010), and marginally correlated with pre-DFP VC (P = 0.047) and to a lesser extent with pre-DFP Pimax (P = 0.063). Univariate analysis using the log rank test revealed that removal rate of AchRAb <30% (P = 0.043) and pre-DFP Pimax <-60 cmH2O (P = 0.024) were significantly associated with prolonged ICU stay. Risk factors for prolonged postoperative stay included post-DFP Pimax <-60 cmH2O (P = 0.017), pre-DFP Pimax <-60 cmH2O (P = 0.031), and post-DFP VC < 1.0 L (P = 0.046). Our results confirmed the efficacy and safety of DFP in prethymectomy preparation for myasthenic patients.

Complications of double-filtration plasmapheresis

BACKGROUND

Double-filtration plasmapheresis (DFP) removes high-molecular-weight molecules semiselectively, thereby minimizing albumin loss, but with subsequent need for fluid substitution. The purpose of this study was to establish the overall incidence of complications during DFP and to analyze the possible contributory factors.

STUDY DESIGN AND METHODS

From November 1993 to October 2003, a total of 2502 plasmapheresis procedures were performed during 515 courses of plasmapheresis in 335 patients. The medical and technical records for these patients were reviewed.

RESULTS

The overall frequency of complications was 67.5 percent per patient, 60.0 percent per course, and 26.3 percent per procedure. The rate of major complications was 18.2 percent of patients, 13.2 percent of courses, and 2.7 percent of procedures. Hemolysis, the most common complication of DFP, occurred in 20 percent of patients. A total of 83 (3.3%) episodes of hypotension were documented in 63 patients. Vascular-access-related complications constituted approximately 17 percent of the total. There was one documented episode of clinically overt bleeding from laboratory coagulopathy necessitating infusion of fresh plasma to stop bleeding. There was no allergic reaction or mortality associated with the DFP procedures. The per-patient frequency of hypotension was higher in cases of chronic inflammatory neuropathy (35.1%) compared to the other illness categories (15.4%-17.3%), with marginal significance demonstrated (p = 0.0611).

CONCLUSION

The safety of DFP treatment has been confirmed by this study. High-risk patients should be monitored carefully during treatment to minimize the occurrence of complications.

Plasmapheresis for severe lipemia: comparison of serum-lipid clearance rates for the plasma-exchange and double-filtration variants

Patients with extremely high triglyceride levels and associated lipemia are at high risk for acute pancreatitis. To evaluate plasmapheresis efficacy for severe hypertriglyceridemia, 18 patients who had not responded to previous therapies were selected for either the plasma-exchange (PE) or double-filtration (DF) treatment variants. After treatment, the mean serum concentrations for triglyceride and cholesterol fell significantly from 1,977.1 and 436.7 mg/dl to 692.6 and 222 mg/dl, respectively. The cholesterol-removal rate was significantly higher for the PE group (P = 0.0082), which also had a lower incidence of hemolysis during the plasmapheresis treatment (P = 0.0430). Improved clearance of serum triglyceride was strongly associated with a lower level of maximal transmembrane pressure (TMP; P = 0.0030), reduced plasmapheresis duration (P = 0.0035), and higher rates of plasma (P = 0.0255) and blood flow (P = 0.0480) during plasmapheresis. In comparison to reports in the literature, the removal rates for serum lipids were lower in our study, possibly as a consequence of early saturation of the plasma separator resulting from blockage caused by the extremely high level of triglyceride-containing lipoproteins. Therefore, PE may be more suitable for the initial treatment of severe hypertriglyceridemia as saturation is prevented. Increasing blood and plasma flow rates, reduction of the TMP level, and reducing effective plasmapheresis duration will improve the clearance of serum lipids during treatment.

Clearance of fibrinogen and von Willebrand factor in serial double-filtration plasmapheresis

Double filtration plasmapheresis (DFP) is a widely used and effective way to clear autoantibodies from plasma. It can, however, transiently alter the hemostatic system and cause a bleeding tendency in some patients. There is limited data on the consecutive effect of serial DFP on the hemostatic system, especially on fibrinogen and von Willebrand factor (vWF) levels. This study measured fibrinogen and vWF serially before and after each session of DFP in 8 patients who received one course of DFP treatment for 3 to 5 consecutive sessions on an alternate-day basis. In each session of DFP, the clearance rate of fibrinogen and vWF exceeded 63 and 45%, respectively. The final levels of fibrinogen and vWF after a full course of DFP were reduced to 14.3 and 51.2% of baseline level, respectively. No bleeding tendency was observed in any of the 34 DFP sessions. In conclusion, although an obvious decrease in fibrinogen level and the modest decrease in vWF were observed after an intensive course of DFP treatment, the low incidence of clinically important bleeding confirms the hemostasis-related safety of DFP.

Pulmonary function study of myasthenia-gravis patients treated with double-filtration plasmapheresis

The aim of this study was to investigate the changes in pulmonary function tests for patients with myasthenia gravis (MG) after treatment with double filtration plasmapheresis (DFP) and to evaluate whether pulmonary function tests predict the efficacy of DFP treatment. Thirty-five MG patients (20 females and 15 males, age range 21-69 years) underwent DFP for between four and eight consecutive sessions. Vital capacity (VC), maximal inspiratory pressure (Pi(max)), and MG score were measured before and after DFP. Based on the results of pulmonary function tests, the patients were divided into dyspnea (VC < 1.0 L or Pi(max) < -25 cm H(2)O) and control groups (VC > 1.0 L and Pi(max) > -25 cm H(2)O). The dyspnea group had a significantly better response to DFP treatment, reflected in the decrease of the MG-score (P=0.0327), and the increase in VC value (P=0.0561). Higher clearance rates of acetylcholine receptor antibody (AchRAb) had a trend toward higher changes of VC. In conclusion, VC might better serve as a predictor for the effect of DFP in the dyspnea patient group because of better correlation with clinical improvement and AchRAb clearance.

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.

Hemodynamic effects of the different vascular accesses used for double-filtration plasmapheresis

Systematic investigations of hemodynamic status during double filtration plasmapheresis (DFP) are rare in the literature. To investigate the hemodynamic effects of the vascular access chosen for DFP, variations in blood pressure (BP) and pulse rate (PR) induced acutely by DFP were prospectively analyzed in 46 myasthenia gravis (MG) patients a standard DFP protocol with isovolumetric saline fluid replacement. BP and PR were monitored at 30-min intervals (baseline, M30, M60, M90, and M120) during the procedures. The patients were randomized into central vein (CV) and peripheral vein (PV) groups based on the vascular access used. Systolic BP (SBP) dropped significantly at M60 (P < 0.05), M90 (P < 0.001), and M120 (P < 0.001) when compared to the baseline level. Symptomatic hypotension was not observed in any of the 46 sessions. SBP values during DFP in the CV group were significantly lower than the PV group's at M60 (93.1 vs. 101.0%, P < 0.05) and marginally lower at M90 (91.2 vs. 97.2%, P = 0.06). There was no significant difference in diastolic BP changes between the two groups. In the CV and PV groups, PR changes during plasmapheresis also differed at M90 (103.4 vs. 94.5%, P < 0.001) and M120 (101.3 vs. 95.0%, P < 0.05). The significantly lower SBP during DFP in the CV group at M60 may be due to the high central vein flow rate and resultant delay in volume replacement. In conclusion, the vascular access selected for DFP plays a role in the pathogenesis of plasmapheresis-related hypotension. Controlling flow rates may help to prevent hypotension.

Coagulation abnormalities in serial double-filtration plasmapheresis

Intensive plasma exchange can transiently alter the hemostatic system. However, the effect of serial double filtration plasmapheresis (DFP) on the hemostatic system has not been adequately described. In this study, we sought to characterize the hemostatic effects of DFP in 32 myasthenia gravis patients who received one course of DFP treatment for five consecutive sessions within 10 days. Platelet count, prothrombin time (PT), partial thromboplastin time (PTT), and serum levels of albumin, globulin, cholesterol, and fibrinogen were measured before and after the course of DFP. Patients were divided into mild hypofibrinogenemia (MH) and severe hypofibrinogenemia (SH) groups based on post-plasmapheresis residual levels of fibrinogen above or below 70 mg/dl. The baseline fibrinogen level was significantly lower in the SH group (P < 0.01). After five sessions of DFP, the fibrinogen level was reduced to below 70 mg/dl in 14 patients (44%). The percentage of excessive prolongation of PT or PTT was significantly higher in the SH group. The SH group also had higher reduction rates of globulin and cholesterol (P < 0.05). Oozing in the punctured site of the central venous catheter occurred in 6 out of 26 patients, with four cases in the MH group and two in the SH group. There was no difference in the overall incidence of bleeding complications between the two groups. Only one episode of clinically overt bleeding occurred during the study after a large-bore femoral catheter was removed soon after the patient had received five consecutive daily treatments. The bleeding stopped after transfusion of 6 units of fresh frozen plasma. In conclusion, despite the obvious reduction of fibrinogen level and the modest decrease in platelet count after an intensive course of DFP treatment, the low incidence of clinically overt bleeding confirmed the safety of DFP.

Hemodynamic study of serial double-filtration plasmapheresis

Although hypotension is a potential complication for all procedures involving extracorporeal circulation, including plasmapheresis, the effects of serial double-filtration plasmapheresis (DFP) on hemodynamic status have rarely been reported. Blood pressure (BP) and pulse rate (PR) were prospectively monitored at 30-minute intervals (baseline, M30, M60, M90, and Ml20) during procedures for 20 myasthenia gravis patients who underwent one course of five consecutive DFP treatments on alternate days, with hemodynamic parameters recorded and analyzed for all sessions. To evaluate the hemodynamic influence of protein loss resulting from serial DFP treatment, additional analysis of serum protein levels including albumin and globulin was conducted before and after the entire course of treatment. Longitudinal analysis on the systolic BP (SBP) changes over five sessions revealed that the SBP at baseline and at M30 dropped significantly during the third and fourth sessions, in comparison to the first (P < 0.05). By contrast, SBP at M120 rose significantly (P < 0.05) after the second session of treatment. A similar trend was revealed for the diastolic BP (DBP) with a significant fall recorded at baseline and at M30 for the fourth session. The PR did not differ significantly during consecutive DFP treatments. Globulin removal rates were correlated significantly with falls in SBP (r(2) = 0.250, P = 0.048) and DBP (r(2) = 0.405, P = 0.008). However, analogous albumin removal rate was not correlated with these hemodynamic parameters. In conclusion, our results confirm that hypoproteinemia is an important factor for contributing to unstable hemodynamics during serial 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.

The six year experience of plasmapheresis in patients with myasthenia gravis

Plasmapheresis (PP) effectively removes autoantibodies in various autoimmune diseases. The use of PP in the treatment of myasthenia gravis (MG) has been widely accepted since the 1970s. The treatment protocol, however, has not been standardized. For the last 6 years, we collected a total of 94 MG patients, 38 males and 56 females aged 14-80 years, who received 175 courses of PP treatment for a total of 823 sessions. The methods we used were double filtration plasmapheresis (DF), immunoadsorption plasmapheresis (IA), and plasma exchange (PE). There were 167 courses of DF, 6 courses of IA, and 2 courses of PE. Each course of treatment consists of 4 to 5 sessions of apheresis. The processed volume of plasma is 1 calculated plasma volume. All patients tolerated PP well although 2.3% of them experienced hypotension. Our experiences are summarized as follows. Both DF and IA effectively ameliorate symptoms and signs of MG. IA removes acetylcholine receptor antibody more effectively than DF does, but clinical effects between these 2 methods are similar. A daily schedule seems more effective than an alternate daily schedule. The optimal number of PP sessions for each course is 4. The factors correlating with better clinical response are high MG score, nonthymoma patients, younger age at onset, and higher removal rate for immunoglobulin G.