Removal Characteristics of Immunoglobulin G Subclasses by Conventional Plasma Exchange and Selective Plasma Exchange

Improving the sensitivity of myelin oligodendrocyte glycoprotein-antibody testing: exclusive or predominant MOG-IgG3 seropositivity-a potential diagnostic pitfall in patients with MOG-EM/MOGAD

BACKGROUND

Myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD) is the most important differential diagnosis of both multiple sclerosis and neuromyelitis optica spectrum disorders. A recent proposal for new diagnostic criteria for MOG-EM/MOGAD explicitly recommends the use of immunoglobulin G subclass 1 (IgG1)- or IgG crystallizable fragment (Fc) region-specific assays and allows the use of heavy-and-light-chain-(H+L) specific assays for detecting MOG-IgG. By contrast, the utility of MOG-IgG3-specific testing has not been systematically evaluated.

OBJECTIVE

To assess whether the use of MOG-IgG3-specific testing can improve the sensitivity of MOG-IgG testing.

METHODS

Re-testing of 22 patients with a definite diagnosis of MOG-EM/MOGAD and clearly positive MOG-IgG status initially but negative or equivocal results in H+L- or Fc-specific routine assays later in the disease course (i.e. patients with spontaneous or treatment-driven seroreversion).

RESULTS

In accordance with previous studies that had used MOG-IgG1-specific assays, IgG subclass-specific testing yielded a higher sensitivity than testing by non-subclass-specific assays. Using subclass-specific secondary antibodies, 26/27 supposedly seroreverted samples were still clearly positive for MOG-IgG, with MOG-IgG1 being the most frequently detected subclass (25/27 [93%] samples). However, also MOG-IgG3 was detected in 14/27 (52%) samples (from 12/22 [55%] patients). Most strikingly, MOG-IgG3 was the predominant subclass in 8/27 (30%) samples (from 7/22 [32%] patients), with no unequivocal MOG-IgG1 signal in 2 and only a very weak concomitant MOG-IgG1 signal in the other six samples. By contrast, no significant MOG-IgG3 reactivity was seen in 60 control samples (from 42 healthy individuals and 18 patients with MS). Of note, MOG-IgG3 was also detected in the only patient in our cohort previously diagnosed with MOG-IgA+/IgG- MOG-EM/MOGAD, a recently described new disease subvariant. MOG-IgA and MOG-IgM were negative in all other patients tested.

CONCLUSIONS

In some patients with MOG-EM/MOGAD, MOG-IgG is either exclusively or predominantly MOG-IgG3. Thus, the use of IgG1-specific assays might only partly overcome the current limitations of MOG-IgG testing and-just like H+L- and Fcγ-specific testing-might overlook some genuinely seropositive patients. This would have potentially significant consequences for the management of patients with MOG-EM/MOGAD. Given that IgG3 chiefly detects proteins and is a strong activator of complement and other effector mechanisms, MOG-IgG3 may be involved in the immunopathogenesis of MOG-EM/MOGAD. Studies on the frequency and dynamics as well as the clinical and therapeutic significance of MOG-IgG3 seropositivity are warranted.

Immunogenicity of SARS-CoV-2 vaccines in patients treated with chronic double filtration plasmapheresis

BACKGROUND

The impact of chronic therapeutic plasmapheresis on humoral response following COVID-19 vaccination is poorly documented, especially among patients treated with double filtration plasmapheresis (DFPP).

OBJECTIVES

This retrospective single-center study evaluated the humoral response after SARS-CoV-2 vaccination and studied anti-SPIKE seropositivity and antibody dynamics in patients with chronic DFPP at our institution.

METHOD

All patients undergoing chronic DFPP at a tertiary center in France from December 2020 to November 2022 were included. We defined one patient subgroup as Group 1 to evaluate anti-SPIKE seropositivity after vaccination, with three groups based on their anti-SPIKE titers: (Group 1A) nonresponders (<0.8 UI/mL), (Group 1B) weak responders (0.8 to <250 binding antibody unit [BAU]/mL), and (Group 1C) strong responders (>250 BAU/mL). Group 2 served to evaluate antibody dynamics with anti-SPIKE levels measured 3 months after initial vaccination, Group 2A having a sustained level and Group 2B a declining pattern.

RESULTS

The 21 patients included had a median age of 63 years, and 13 (56%) were male. The indications for chronic DFPP mainly included dysimmune pathologies (15; 71%) and familial dyslipidemia (6; 29%). For the humoral response to vaccination in Patient Group 1, the only nonresponder was a patient who had undergone kidney transplantation 30 months earlier and was on immunosuppressive medication. For Patient Group 2, the median follow-up of antibody titers was 13 months [12-13]. Two distinct patterns of anti-SPIKE dynamics were observed: a rapid decline in anti-SPIKE antibody titers within 6 months following the initial vaccination or booster dose (n = 10 [71.4%] Group 2A) and stable anti-SPIKE levels above 250 BAU/mL over >6 months (n = 4 [28.6%] Group 2B) with more patients with familial dyslipidemia in the former.

CONCLUSIONS

Humoral response to SARS-CoV-2 vaccination appears robust in patients undergoing chronic DFPP and may be linked to patients' immune status rather than DFPTP itself. Our results support current recommendations for administering three doses of vaccine with a booster every 6 months.

FcRn Inhibitor Therapies in Neurologic Diseases

In the last decade, the landscape of treating autoimmune diseases has evolved with the emergence and approval of novel targeted therapies. Several new biological agents offer selective and target-specific immunotherapy and therefore fewer side effects, such as neonatal Fc receptor (FcRn)-targeting therapy. Neonatal Fc receptor-targeted therapies are engineered to selectively target FcRn through various methods, such as Fc fragments or monoclonal anti-FcRn antibodies. These approaches enhance the breakdown of autoantibodies by blocking the immunoglobulin G recycling pathway. This mechanism reduces overall plasma immunoglobulin levels, including the levels of pathogenic autoantibodies, without affecting the other immunoglobulin class immunoglobulin A, immunoglobulin E, immunoglobulin M, and immunoglobulin D levels. Drugs that inhibit FcRn include efgartigimod, rozanolixizumab, batoclimab, and nipocalimab. These medications can be administered either intravenously or subcutaneously. Numerous clinical trials are currently underway to investigate their effectiveness, safety, and tolerability in various neurological conditions, including myasthenia gravis and other neurological disorders such as chronic inflammatory demyelinating polyneuropathy, myositis, neuromyelitis optica, and myelin oligodendrocyte glycoprotein antibody disease. Positive results from clinical trials of efgartigimod and rozanolixizumab led to their approval for the treatment of generalized myasthenia gravis. Additional clinical trials are still ongoing. Neonatal Fc receptor inhibitor agents seem to be well tolerated. Reported adverse events include headache (most commonly observed with efgartigimod and rozanolixizumab), upper respiratory tract infection, urinary tract infection, diarrhea, pyrexia, and nausea. Additionally, some of these agents may cause transient hypoalbuminemia and hypercholesterolemia notably reported with batoclimab and nipocalimab. In this review, we discuss the available clinical data for FcRN inhibitor agents in treating different neurological autoimmune diseases.

Polyclonal hypergammaglobulinaemia: towards definition of a threshold

Background

Polyclonal hypergammaglobulinaemia (PH) represents a classic diagnosis problem in internal medicine. However, there is no consensus threshold for PH. The aim of this study was to define a threshold for PH.

Methods

We conducted a retrospective multicentric study using laboratory biological databases between 1 January 2016 and 31 December 2016 in two university hospitals and one non-university hospital. All patients 18 years old or over and with at least one serum protein electrophoresis (SPE) available in 2016 were included. Exclusion criteria were monoclonal, biclonal, or oligoclonal spikes or, in case of hypogammaglobulinaemia, proven free light chain gammopathy. The main endpoint was to define the threshold values for PH in this population. Another objective was to define the 95th percentile of the distribution.

Results

20 766 SPEs were included in this cohort. The PH threshold on 95th percentile was 18.9 g/L. The threshold varied according to geographical areas.

Conclusions

This is the first study to scientifically define a PH threshold. The main limitation is that our threshold is only biological. The study was not designed to associate this threshold with a clinically active disease. In conclusion, while the 19 g/L cut-off seems the most relevant threshold, but it will need to be validated by prospective studies.

Phase 2 multiple-dose study of an FcRn inhibitor, rozanolixizumab, in patients with primary immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is a predominantly immunoglobulin G (IgG)-autoantibody-mediated disease characterized by isolated thrombocytopenia. Rozanolixizumab, a subcutaneously infused humanized monoclonal anti-neonatal Fc receptor (FcRn) antibody, reduced serum IgG in healthy volunteers. In this phase 2, multicenter, open-label study, patients with persistent/chronic primary ITP received 1 to 5 once-weekly subcutaneous infusions of rozanolixizumab (cumulative doses, 15-21 mg/kg). Primary objectives were safety and tolerability, and secondary objectives were clinical efficacy (change in platelet count) and pharmacodynamic effect (change in IgG). In all, 51 (77.3%) of 66 patients reported 1 or more adverse events (AEs), all mild-to-moderate, most commonly headaches (26 [39.4%] of 66), of which 15 were treatment related. Four patients had serious AEs, but none were treatment related. No AEs resulted in discontinuation of the study drug. No serious infections occurred. Platelet counts of ≥50 × 109/L were achieved at least once at any time after multiple infusions (5 × 4, 3 × 7, or 2 × 10 mg/kg: 35.7%, 35.7%, and 45.5% of patients, respectively) or single infusions (15 or 20 mg/kg: 66.7% and 54.5% patients, respectively). Minimum mean IgG levels and maximum mean platelet counts both occurred by day 8 in the higher (15 and 20 mg/kg) single-dose cohorts and maximum platelet count occurred by day 11 onward in the multiple-dose cohorts. No clinically meaningful changes occurred in IgA, IgM, IgE, or albumin levels. In patients with persistent/chronic primary ITP, rozanolixizumab demonstrated a favorable safety profile and rapid, substantial platelet increases concordant with substantial IgG reductions, especially with single doses. By day 8, in the 15 and 20 mg/kg single-dose cohorts, >50% patients achieved clinically relevant platelet responses (≥50 × 109/L), coinciding with the lowest mean IgG levels. These data support phase 3 development of rozanolixizumab in persistent/chronic primary ITP. This trial was registered at www.clinicaltrials.gov as #NCT02718716.

A case of anti-aquaporin-4 antibody-positive optic neuritis treated by selective immunoadsorption

Anti-aquaporin-4 (AQP4) antibody-positive optic neuritis is a condition in which a patient testing positive for anti-AQP4 antibody presents with optic neuritis only. The disease is classified as a neuromyelitis optica spectrum disorder (NMOSD) and is a steroid-resistant refractory optic neuritis. Patients are treated by oral administration of steroids, steroid pulse therapy, and apheresis therapy. The patient in our case was a 48-year-old female who was diagnosed with anti-AQP4 antibody-positive optic neuritis by her ophthalmologist, and was referred to our hospital. Selective plasma exchange (SePE) was initially started, but she strongly preferred treatment as an outpatient due to family circumstances. Therefore, selective immunoadsorption (SeIA) was used from the second session to minimize loss of coagulation factors. The RRs were 16.5-33.3% for anti-AQP4 antibody, 7.48-18.57% for fibrinogen, and 0.8-4.57% for factor XIII. After the 7th SeIA session, the patient was followed up with a maintenance dose of 10 mg/day oral prednisolone as an outpatient at our Department of Ophthalmology. This is the first report to investigate the removal rate (RR) of anti-AQ4 antibody using SeIA. In our case, the anti-AQP4 antibody level before the last SeIA session was still not completely negative, but there was clinical improvement in vision. SeIA was highly effective in maintaining coagulation factor levels. Therefore, our results suggest that SeIA is a safe treatment that can be performed in an outpatient setting.

NMOSD acute attack: Understanding, treatment and innovative treatment prospect

Neuromyelitis optica spectrum disorder (NMOSD) is a group of severe inflammatory demyelinating disorders of the central nervous system that involves the optic nerve and spinal cord. Currently the therapeutic options for an acute attack in NMOSD are limited and rarely characterized in clinical studies. This review discussed the overall characteristics of acute attack of NMOSD, related risk factor, prognosis and management. Considering the huge unmet needs and the emergence of new therapeutic targets, we also reviewed innovative treatments that might alleviate attack damage, along with the challenges to evaluate new drug for acute attack in NMOSD.

Anti-MDA-5 antibody-positive clinically amyopathic dermatomyositis with rapidly progressive interstitial lung disease treated with therapeutic plasma exchange: A case series

We present six cases of antimelanoma differentiation-associated gene 5 antibody (anti-MDA5-Ab)-positive clinically amyopathic dermatomyositis (CADM) with rapidly progressive interstitial lung disease (RP-ILD), which is known to have a poor prognosis. The outcomes of these cases are described after treatment with therapeutic plasma exchange (TPE). Clinical and therapeutic data for patients with CADM with RP-ILD were collected retrospectively from medical records. All six patients received early intensive care including high-dose corticosteroids, intravenous cyclophosphamide, and a calcineurin inhibitor, but lung disease and hypoxia became more severe. TPE was performed over a median of 9.5 sessions (range 3-14) per patient, and the median duration from admission to TPE was 23 days. Three patients received combined direct hemoperfusion using a polymyxin B-immobilized fiber column (PMX-DHP) therapy on successive days to manage acute respiratory failure. Four patients survived and two died due to respiratory failure. In the survival cases, ferritin decreased, and ferritin and KL-6 were lower at diagnosis. The patients who died had a higher alveolar-arterial oxygen difference and more severe lung lesions at the time of initiation of TPE. These findings indicate that a combination of conventional therapy and TPE may be useful for improvement of the prognosis of CADM with RP-ILD at the early stage of onset.

Physiological role of plasma and its components and the clinical implications of different methods of apheresis: A narrative review

Nowadays, therapeutic plasmapheresis (TP) is accepted as part of the treatment for specific groups of diseases. The availability of different methods, including double filtration and adsorption, increases selectivity for the removal of substances. However, the use of these techniques requires a thorough understanding of the characteristics and components of plasma. By considering pivotal papers from several databases, the aim of this narrative review is to describe the characteristics of plasma related to apheresis techniques. We have tried to cover the clinical implications including physiology, estimation of plasma volume, viscosity, and a description of its components including the size, volume of distribution, and half-lives of the different substances to be removed or maintained depending on the clinical situation and applied apheresis technique. Applying this knowledge will help us to choose the right method and dosage and improve the efficacy of the procedure by preventing or addressing any complications.

Comparison of selective plasma exchange and plasmadialfiltration with MARS and Prometheus systems in the treatment of liver failure

The mortality of patients with hepatic failure remains high. Often the patient's life can be saved only with extracorporeal liver support (ELS). ELS systems – MARS® и Prometheus® have proved their efficacy but their widespread use is constrained by their very high cost. Introduction in clinical practice of new affordable ELS systems is a topical issue. The objective: to compare clinical and laboratory effects of selective plasma exchange (SPE), plasmadialfiltration (PDF) with use of the selective membrane plasma separators EvaclioTM and MARS® and Prometheus® (FPSA) systems in the treatment of liver failure. Subjects and methods: 15 extracorporeal procedures of each type were performed in 52 patients with acute liver failure (14) and acute-on-chronic liver failure (38): MARS, FPSA, PDF, SPE with use of Evaclio ЕС-2C, and ЕС-3C, ЕС-4C. The clinical and laboratory parameters (total, direct and indirect bilirubin, total protein, albumin, creatinine, urea, etc.), severity of the condition according to MELD score were determined before and after the session and the next morning. Changes, side effects and complications of procedures were assessed and compared. Results. Reduction of concentration of direct bilirubin was comparable with FPSA, PDF and SPE on Evaclio ЕС-3C20 и ЕС-4C20 (38-42%), indirect bilirubin – with PDF and SPE on Evaclio ЕС-3C20 и ЕС-4C20 (29-34%). Low-molecular metabolites (urea, creatinine) were better removed with FPSA (35-44%) and PDF (40-42%). The reduction of their concentration with SPE was insignificant. The reduction of albumin level was the highest with FPSA (10.2%) and SPE on Evaclio ЕС-4C20 (14.3%). All investigated ELS methods did not exert a significant influence on the basic parameters of blood coagulation and quantity of blood cells. No side effects and complications were observed. Conclusion: Selective plasma exchange and plasmadiafiltration are generally comparable in clinical and laboratory effects in the treatment of liver failure with MARS and Prometheus system provided significantly lower costs.

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.

A Solution Kinetics Simulation Method for Conventional and Selective Plasma Exchange Using a Complete Mixed Reactor Model

At present, conventional plasma exchange (CPE) sets removal rate, replacement fluid volume and replacement fluid albumin (Alb) concentration according to the first-order kinetics of mass balance for removal of pathogenic substances. With the spread of selective plasma exchange (SePE), it has become necessary to set the removal rate and replacement fluid Alb concentration based on the initial concentration for each performance of the plasma separator. Considering the patient as a single reactor we devised a complete mixed reactor model simulating the concentration change in the reactor. Our formula is obtained by adding membrane performance and replacement fluid concentration to formulas currently available and can be used for both CPE and SePE. For the in vitro experiment, fresh frozen plasma stored in a bag was used to simulate a patient's circulating plasma. Plasma was separated by plasma separator Evacure EC-4A10 (EC-4A) (Kawasumi Laboratories Inc., Tokyo, Japan) while a replacement Alb solution was simultaneously entered into the circuit at the same rate as separation. IgG, Alb, total protein (TP), and fibrinogen (Fib) concentrations were measured every 10 min and examined for correlation with the value predicted by the mass balance formula. The concentration of each solute was measured 21 times during the 195 min of the experiment. The rate of change of each solute was IgG 76%, Alb 58%, TP 58%, and Fib 32%. Experimental values and predicted values showed significant correlation (IgG: r²  = 0.9962; Fib: r²  = 0.9535; Alb: r²  = 0.9808; TP: r²  = 0.9721, all P < 0.05). Since the solute concentration change in SePE can be predicted, this mass balance formula is useful for setting treatment conditions for both CPE and SePE.

Removal Characteristics of Immunoadsorption with the Tryptophan-Immobilized Column Using Conventional and Selective Plasma Separators in the Treatment of Myasthenia Gravis

Autoimmune neurological diseases are often treated by immunoadsorption using a conventional plasma separator and tryptophan-immobilized column (IA). However, there is only one case report on treatment with immunoadsorption using a selective plasma separator and tryptophan-immobilized column (SeIA) in clinical practice. This study aimed to investigate the removal characteristics of antibodies against acetylcholine receptors (AChRAb), immunoglobulin G, fibrinogen, and factor XIII (FXIII) in IA and SeIA in four patients with myasthenia gravis. A total of 19 sessions of immunoadsorption were performed (five sessions of IA and 14 sessions of SeIA) when the processed plasma volume was 2 L. The corresponding reductions were 52.5% ± 6.2% for AChRAb, 58.8% ± 4.2% for fibrinogen, and 36.9% ± 5.5% for FXIII after one session of IA. The corresponding reductions were 45.2% ± 9.9% for AChRAb, 3.5% ± 6.9% for fibrinogen, and -4.6% ± 11.1% for FXIII after one session of SeIA. The removal rates for AChRAb, fibrinogen, and FXIII in IA were significantly higher than those in SeIA. IA could effectively remove AChRAb, and SeIA could retain fibrinogen and FXIII. IA can be combined with SeIA, resulting in both IgG autoantibodies removal by IA and retention of coagulation factors by SeIA.

Generation and characterization of a high affinity anti-human FcRn antibody, rozanolixizumab, and the effects of different molecular formats on the reduction of plasma IgG concentration

Rozanolixizumab (UCB7665), a humanized high-affinity anti-human neonatal Fc receptor (FcRn) monoclonal antibody (IgG4P), has been developed to reduce pathogenic IgG in autoimmune and alloimmune diseases. We document the antibody isolation and compare rozanolixizumab with the same variable region expressed in various mono-, bi- and trivalent formats. We report activity data for rozanolixizumab and the different molecular formats in human cells, FcRn-transgenic mice, and cynomolgus monkeys. Rozanolixizumab, considered the most effective molecular format, dose-dependently and selectively reduced plasma IgG concentrations in an FcRn-transgenic mouse model (no effect on albumin). Intravenous (IV) rozanolixizumab dosing in cynomolgus monkeys demonstrated non-linear pharmacokinetics indicative of target-mediated drug disposition; single IV rozanolixizumab doses (30 mg/kg) in cynomolgus monkeys reduced plasma IgG concentration by 69% by Day 7 post-administration. Daily IV administration of rozanolixizumab (initial 30 mg/kg loading dose; 5 mg/kg daily thereafter) reduced plasma IgG concentrations in all cynomolgus monkeys, with low concentrations maintained throughout the treatment period (42 days). In a 13-week toxicology study in cynomolgus monkeys, supra-pharmacological subcutaneous and IV doses of rozanolixizumab (≤ 150 mg/kg every 3 days) were well tolerated, inducing sustained (but reversible) reductions in IgG concentrations by up to 85%, with no adverse events observed. We have demonstrated accelerated natural catabolism of IgG through inhibition of IgG:FcRn interactions in mice and cynomolgus monkeys. Inhibition of FcRn with rozanolixizumab may provide a novel therapeutic approach to reduce pathogenic IgG in human autoimmune disease. Rozanolixizumab is being investigated in patients with immune thrombocytopenia (NCT02718716) and myasthenia gravis (NCT03052751).

The FcRn inhibitor rozanolixizumab reduces human serum IgG concentration: A randomized phase 1 study

Pathogenic immunoglobulin G (IgG) autoantibodies characterize some human autoimmune diseases; their high concentration and long half-life are dependent on recycling by the neonatal Fc receptor (FcRn). Inhibition of FcRn is an attractive new treatment concept for IgG-mediated autoimmune diseases. Rozanolixizumab (UCB7665; CA170_01519.g57 IgG4P) is an anti-human FcRn monoclonal antibody. In cynomolgus monkeys, rozanolixizumab reduced IgG (maximum 75 to 90% by about day 10), was well tolerated, and did not increase risk of infection. We also report a first-in-human, randomized, double-blind, placebo-controlled, dose-escalating study of intravenous (IV) or subcutaneous (SC) rozanolixizumab in healthy subjects (NCT02220153). The primary objective was to evaluate safety and tolerability. Secondary objectives were assessment of rozanolixizumab pharmacokinetics and pharmacodynamics, including effects on circulating IgG concentrations. Forty-nine subjects were randomized to receive rozanolixizumab (n = 36) or placebo (n = 13) across six cohorts. The first three cohorts received IV doses, and the subsequent three cohorts received SC doses, of rozanolixizumab 1, 4, or 7 mg/kg (n = 6 for each cohort; plus n = 7 or 6 for placebo, respectively). The most frequent treatment-emergent adverse event [TEAE; headache, 14 of 36 (38.9%) subjects] was dose-dependent and more prominent after IV administration. Severe TEAEs occurred in four subjects, all in the highest-dose IV group [headache (n = 3) and back pain (n = 1)]. Rozanolixizumab pharmacokinetics demonstrated nonlinear increases with dose. There were sustained dose-dependent reductions in serum IgG concentrations (IV and SC rozanolixizumab). These data provide clinical evidence for the therapeutic potential of rozanolixizumab.

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.