Immunoadsorption with regenerating systems in neurological disorders --A single center experience

Clinical improvement of Long-COVID is associated with reduction in autoantibodies, lipids, and inflammation following therapeutic apheresis

In the aftermath of the COVID-19 pandemic, we are witnessing an unprecedented wave of post-infectious complications. Most prominently, millions of patients with Long-Covid complain about chronic fatigue and severe post-exertional malaise. Therapeutic apheresis has been suggested as an efficient treatment option for alleviating and mitigating symptoms in this desperate group of patients. However, little is known about the mechanisms and biomarkers correlating with treatment outcomes. Here, we have analyzed in different cohorts of Long-Covid patients specific biomarkers before and after therapeutic apheresis. In patients that reported a significant improvement following two cycles of therapeutic apheresis, there was a significant reduction in neurotransmitter autoantibodies, lipids, and inflammatory markers. Furthermore, we observed a 70% reduction in fibrinogen, and following apheresis, erythrocyte rouleaux formation and fibrin fibers largely disappeared as demonstrated by dark field microscopy. This is the first study demonstrating a pattern of specific biomarkers with clinical symptoms in this patient group. It may therefore form the basis for a more objective monitoring and a clinical score for the treatment of Long-Covid and other postinfectious syndromes.

Post COVID and Apheresis - Where are we Standing?

A continual increase in cases of Long/Post COVID constitutes a medical and socioeconomic challenge to health systems around the globe. While the true extent of this problem cannot yet be fully evaluated, recent data suggest that up to 20% of people with confirmed SARS-CoV-2 suffer from clinically relevant symptoms of Long/Post COVID several weeks to months after the acute phase. The clinical presentation is highly variable with the main symptoms being chronic fatigue, dyspnea, and cognitive symptoms. Extracorporeal apheresis has been suggested to alleviate symptoms of Post/COVID. Thus, numerous patients are currently treated with apheresis. However, at present there is no data from randomized controlled trials available to confirm the efficacy. Therefore, physicians rely on the experience of practitioners and centers performing this treatment. Here, we summarize clinical experience on extracorporeal apheresis in patients with Post/COVID from centers across Germany.

COVID-19 and Therapeutic Apheresis

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, is an unprecedented challenge for the global community. The pathogenesis of COVID-19, its complications and long term sequelae (so called Long/Post-COVID) include, in addition to the direct virus-induced tissues injury, multiple secondary processes, such as autoimmune response, impairment of microcirculation, and hyperinflammation. Similar pathological processes, but in the settings of neurological, cardiovascular, rheumatological, nephrological, and dermatological diseases can be successfully treated by powerful methods of Therapeutic Apheresis (TA). We describe here the rationale and the initial attempts of TA treatment in severe cases of acute COVID-19. We next review the evidence for the role of autoimmunity, microcirculatory changes and inflammation in pathogenesis of Long/Post COVID and the rationale for targeting those pathogenic processes by different methods of TA. Finally, we discuss the impact of COVID-19 pandemic on patients, who undergo regular TA treatments due to their underlying chronic conditions, with the specific focus on the patients with inherited lipid diseases being treated at the Dresden University Apheresis Center.

Safety and Tolerability of Plasma Exchange and Immunoadsorption in Neuroinflammatory Diseases

Plasma exchange (PE) and immunoadsorption (IA) are frequently used for treatment of various autoimmune-mediated neurological diseases, including multiple sclerosis (MS), chronic inflammatory demyelinating polyneuropathy (CIDP), and Guillain-Barré syndrome (GBS). Although both methods are generally regarded as well-tolerated treatment options, evidence for safety and tolerability is low for most indications and largely relies on small case series. In this study, we retrospectively analysed adverse events (AEs) and laboratory changes in 284 patients with various neurological indications who received either PE (n = 65, 113 cycles) or IA (n = 219, 435 cycles) between 2013 and 2020 in our Neurology department. One standard treatment cycle for PE as well as IA consisted of five treatments on five consecutive days. During every treatment, the 2.0-2.5-fold individual plasma volume (PV) was treated in IA, while in PE, the 0.7-fold individual PV was replaced by human albumin solution. Overall, both methods showed an excellent safety profile; no deaths of life-threatening adverse events were recorded. Severe AEs (corresponding to grade 3 on the Common Terminology Criteria for Adverse Events grading scale v5.0) including three patients with sepsis, one pneumonia, and one pneumothorax were present in 5/435 IA cycles (1.1%); in the PE group, no severe AEs were recorded. Furthermore, although advantageous tolerability is generally considered the main advantage of IA over PE, we found that overall frequency of AEs (including grades 1 and 2) was higher in IA (67.1% of all cycles) compared to PE (35.4%; p < 0.001). The low incidence of AEs in PE might be caused by the lower PV exchanged during each treatment (0.7-fold) compared to previous studies which predominantly exchanged the 1.0-1.5-fold PV. In order to verify this hypothesis as well as confirming the efficacy of this lower-dosed scheme, prospective studies comparing different treatment regimens are needed.

Immunoadsorption enables successful rAAV5-mediated repeated hepatic gene delivery in nonhuman primates

Adeno-associated virus (AAV)-based liver gene therapy has been shown to be clinically successful. However, the presence of circulating neutralizing antibodies (NABs) against AAV vector capsids remains a major challenge as it may prevent successful transduction of the target cells. Therefore, there is a need to develop strategies that would enable AAV-mediated gene delivery to patients with preexisting anti-AAV NABs. In the current study, the feasibility of using an immunoadsorption (IA) procedure for repeated, liver-targeted gene delivery in nonhuman primates was explored. The animals were administered IV with recombinant AAV5 (rAAV5) carrying the reporter gene human secreted embryonic alkaline phosphatase (hSEAP). Seven weeks after the first rAAV treatment, all of the animals were readministered with rAAV5 carrying the therapeutic hemophilia B gene human factor IX (hFIX). Half of the animals administered with rAAV5-hSEAP underwent IA prior to the second rAAV5 exposure. The transduction efficacies of rAAV5-hSEAP and rAAV5-hFIX were assessed by measuring the levels of hSEAP and hFIX proteins. Although no hFIX was detected after rAAV5-hFIX readministration without prior IA, all animals submitted to IA showed therapeutic levels of hFIX expression, and a threshold of anti-AAV5 NAB levels compatible with successful readministration was demonstrated. In summary, our data demonstrate that the use of a clinically applicable IA procedure enables successful readministration of an rAAV5-based gene transfer in a clinically relevant animal model. Finally, the analysis of anti-AAV NAB levels in human subjects submitted to IA confirmed the safety and efficacy of the procedure to reduce anti-AAV NABs. Furthermore, clinical translation was assessed using an immunoglobulin G assay as surrogate.

Plasma Exchange or Immunoadsorption in Demyelinating Diseases: A Meta-Analysis

Multiple sclerosis (MS) is an inflammatory disease mainly affecting the central nervous system. In MS, abnormal immune mechanisms induce acute inflammation, demyelination, axonal loss, and the formation of central nervous system plaques. The long-term treatment involves options to modify the disease progression, whereas the treatment for the acute relapse has its focus in the administration of high-dose intravenous methylprednisolone (up to 1000 mg daily) over a period of three to five days as a first step. If symptoms of the acute relapse persist, it is defined as glucocorticosteroid-unresponsive, and immunomodulation by apheresis is recommended. However, several national and international guidelines have no uniform recommendations on using plasma exchange (PE) nor immunoadsorption (IA) in this case. A systematic review and meta-analysis was conducted, including observational studies or randomized controlled trials that investigated the effect of PE or IA on different courses of MS and neuromyelitis optica (NMO). One thousand, three hundred and eighty-three patients were included in the evaluation. Therapy response in relapsing-remitting MS and clinically isolated syndrome was 76.6% (95%CI 63.7–89.8%) in PE- and 80.6% (95%CI 69.3–91.8%) in IA-treated patients. Based on the recent literature, PE and IA may be considered as equal treatment possibilities in patients suffering from acute, glucocorticosteroid-unresponsive MS relapses.

Safety and efficacy of immunoadsorption versus plasma exchange in steroid-refractory relapse of multiple sclerosis and clinically isolated syndrome: A randomised, parallel-group, controlled trial

BACKGROUND

Plasma exchange (PE) constitutes the standard therapy for steroid-refractory relapse in multiple sclerosis and clinically isolated syndrome. Immunoadsorption (IA) is an alternative method of apheresis which selectively removes immunoglobulines (Ig) while preserving other plasma proteins. Although IA is regarded as a well-tolerated, low-risk procedure, high-level evidence for its efficacy is lacking. Therefore, we sought to investigate whether IA is superior to PE in patients with acute relapse of multiple sclerosis or clinically isolated syndrome who had insufficiently responded to high-dose intravenous methylprednisolone (MP).

METHODS

Patients with acute relapse of multiple sclerosis or clinically isolated syndrome and without complete clinical remission of symptoms after at least one cycle of high-dose intravenous MP therapy were enrolled to our randomised, controlled, parallel-group, monocentric trial. Eligible patients were aged at least 12 years and had no clinical or laboratory signs of systemic infection. Eligible patients were randomly assigned (1:1) to receive either IA or PE. Patients in both groups received 5 treatments on 5 consecutive days. In the IA group, the 2.0-fold individual total plasma volume was processed on day 1, and the 2.5-fold on days 2-5. In the PE group, 2 liters of plasma (corresponding to the 0.69 ± 0.12-fold individual total plasma volume) were removed each day and substituted by 5% human albumin solution. Patients were followed up directly after last apheresis as well as 2 and 4 weeks after last treatment. The primary endpoint was change of the Multiple Sclerosis Functional Composite (MSFC) after 4 weeks compared to baseline. Analyses of primary outcome and safety measures were done in all patients who received at least one treatment (intention-to-treat-population). The trial is registered with ClinicalTrials.gov, number NCT02671682.

FINDINGS

Between January 21, 2016, and October 26, 2018, 63 patients were screened for eligibility, and 61 patients were randomly assigned to receive IA (n = 31) or PE (n = 30). All randomised patients were included in the intention-to-treat-analysis. For the primary outcome, the median improvement of MSFC after 4 weeks compared to baseline was 0.385 (IQR 0.200-0.675; p < 0.001) in the IA group and 0.265 (IQR 0.100-0.408; p < 0.001) in the PE group. Improvement in the IA group was significantly larger (p = 0.034) compared to PE. Response rates after 4 weeks were 86.7% in the IA group and 76.7% in the PE group. One deep venous thrombosis occurred in each group.

INTERPRETATION

Both IA and PE were safe in patients with steroid-refractory relapse and resulted in significant improvements of the primary outcome MSFC after 4 weeks compared to baseline. IA patients showed significantly larger improvements of MSFC compared to PE patients after 4 weeks. The results indicate a potential superiority of IA compared to PE in treatment of steroid-refractory relapse in multiple sclerosis and clinically isolated syndrome, which has to be confirmed by future studies.

FUNDING

Fresenius Medical Care Deutschland GmbH, Bad Homburg, Germany.

Therapeutic Apheresis in Acute Relapsing Multiple Sclerosis: Current Evidence and Unmet Needs-A Systematic Review

Multiple sclerosis (MS) is the most abundant inflammatory demyelinating disorder of the central nervous system. Despite recent advances in its long-term immunomodulatory treatment, MS patients still suffer from relapses, significantly contributing to disability accrual. In recent years, apheresis procedures such as therapeutic plasma exchange (TPE) and immunoadsorption (IA) have been recognized as two options for treating MS relapses, that do not respond to standard treatment with corticosteroids. TPE is already incorporated in most international guidelines, although evidence for its use resulted mostly from either case series or small unblinded and/or non-randomized trials. Data on IA are still sparse, but several studies indicate comparable efficacy between both apheresis procedures. This article gives an overview of the published evidence on TPE and IA in the treatment of acute relapses in MS. Further, we outline current evidence regarding individual outcome predictors, describe technical details of apheresis procedures, and discuss apheresis treatment in children and during pregnancy.

Therapeutic plasma exchange in paediatric neurology: a critical review and proposed treatment algorithm

Therapeutic plasma exchange (TPE) has been a key immunotherapeutic strategy in numerous neurological syndromes, predominantly during the acute phase of illness. This paper reviews the indications, strength of evidence, and safety of TPE in children with neurological conditions. The rarity of these immune conditions in children, alongside an often incomplete understanding of their pathobiology, has limited the development of a robust scientific rationale for TPE therapy and the feasibility of conducting larger controlled trials. TPE continues to be used, but is a costly therapy with common adverse effects. Uncertainty remains over how to compare the different TPE methods, the optimal dosage of therapy, and monitoring and integration of TPE with other immunotherapies. Further studies are also required to define the indications and benefits of TPE and assess evolving technologies such as immunoadsorption.

WHAT THIS PAPER ADDS

Studies investigating therapeutic plasma exchange (TPE) are small and mainly uncontrolled. They provide evidence for the efficacy of TPE in childhood neuro-inflammatory conditions. TPE is generally well tolerated provided key adverse effects are anticipated and avoided. Systematic dosing and objective assessment of treatment effect should be priorities for future research.

Low rate of infectious complications following immunoadsorption therapy without regular substitution of intravenous immunoglobulins

INTRODUCTION

Immunoadsorption (IA) is increasingly used instead of plasma exchange due to lower risk of side effects and a higher selectivity. As a consequence of the reduction of immunoglobulins (Ig), the rate of infectious complications might increase in those patients. We therefore aimed to investigate the infection rate following IA without intravenous IG (IVIG) substitution in our apheresis center, where patients do not receive IVIG on a regular basis.

MATERIAL AND METHODS

We conducted a retrospective analysis of the IA treatments performed between 2010 and 2015 without IVIG substitution and collected data on patient age, diagnosis, number of IA treatments, serum levels of Ig, total protein, albumin, C-reactive protein (CRP) and infectious complications that occurred within 2 months after the IA treatment cycle.

RESULTS

A total number of 52 patients (27 females) received at least 5 IA sessions using the following adsorbers: TheraSorb™-Ig (n = 3), TheraSorb™-Ig flex (n = 44), TheraSorb™ Ig pro (n = 1) and TheraSorb™-IgE (n = 5). The median number of treatment sessions was 8.8 [range 5-16], the median IgG reduction was 82 [11-99] %. Serum albumin was decreased by 8%. The median CRP levels remained normal until the end of therapy and within 2 months after that (3.10 and 4.30 mg/L respectively). Only 4 patients had infections (7.7%). Three of them received additional immunosuppressive therapy.

CONCLUSIONS

Immunoadsorption leads to a significant reduction of IgG. CRP as inflammatory marker is not affected. Even without substitution of IVIG the complication rate directly linked with IA is low and questionable.

In vivo imaging of murine vasodynamics analyzing different mouse strains by optical coherence tomography

BACKGROUND AND AIMS

We tried to circumvent the limitations of standard organ chamber experiments using in vivo optical coherence tomography (OCT) to analyze the vascular function of small arteries in different mouse strains.

METHODS

OCT images were acquired with a two-axis galvanometer scanner head. Time series (3 frames per second, 300 × 512 pixel per frame) of cross-sectional images were analyzed with image processing software measuring the time course of vessel lumen dynamics. Vascular function of murine saphenous artery of male C57BL/6 (wild-type) and hypercholesterolemic LDLR knockout (LDLR^-/-) mice was analyzed at 6 weeks and after 14 weeks feeding a control or high-fat diet containing 21.2% butter fat and 2.1 mg/kg cholesterol. Vasoconstriction and vasodilation was analyzed by OCT in response to 80 mM K⁺ and 1 mM SNP.

RESULTS

The OCT technique allowed determination of inner diameter, flow resistance, maximal velocity of diameter change and time to half-maximal diameter change in murine saphenous arteries of wild-type and LDLR^-/- mice. LDLR^-/- had impaired vasodilation and changes in vasodynamics after 14 weeks on control or high-fat diet, compared to wild-type mice. The diameter of the saphenous artery of LDLR^-/- mice was reduced after vasoconstriction (38 ± 7 μm vs 12 ± 6 μm) and vasodilation (245 ± 8 μm vs 220 ± 10 μm) (P < 0.05 vs C57BL/6).

CONCLUSION

OCT was used as an innovative method to image vascular function of small arteries of wild-type and hypercholesterolemic LDLR^-/- mice after high-fat diet. The method offers the ability to display differences in the vasodynamics at early stages of endothelial dysfunction in vivo.