Meta-analysis of clinical studies of the efficacy of plasma exchange in the treatment of chronic progressive multiple sclerosis

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Role of complement and potential of complement inhibitors in myasthenia gravis and neuromyelitis optica spectrum disorders: a brief review

The complement system is a powerful member of the innate immune system. It is highly adept at protecting against pathogens, but exists in a delicate balance between its protective functions and overactivity, which can result in autoimmune disease. A cascade of complement proteins that requires sequential activation, and numerous complement regulators, exists to regulate a proportionate response to pathogens. In spite of these mechanisms there is significant evidence for involvement of the complement system in driving the pathogenesis of variety of diseases including neuromyelitis optica spectrum disorders (NMOSD) and myasthenia gravis (MG). As an amplification cascade, there are an abundance of molecular targets that could be utilized for therapeutic intervention. Clinical trials assessing complement pathway inhibition in both these conditions have recently been completed and include the first randomized placebo-controlled trial in NMOSD showing positive results. This review aims to review and update the reader on the complement system and the evolution of complement-based therapeutics in these two disorders.

Immunoadsorption or plasma exchange in steroid-refractory multiple sclerosis and neuromyelitis optica

BACKGROUND

Plasma exchange (PE) and immunoadsorption (IA) are alternative treatments of steroid-refractory relapses of multiple sclerosis (MS) or neuromyelitis optica (NMO).

METHODS

Adverse events and neurological follow-ups in 127 MS- (62 PE, 65 IA) and 13 NMO- (11 PE, 2 IA) patients were retrospectively analyzed. Response was defined by improvements in either expanded disability status scale (EDSS) by at least 1.0 or visual acuity (VA) to 0.5, confirmed after 3 and/or 6 months.

RESULTS

Hundred and forty patients were included in safety analysis, 102 patients provided sufficient neurological follow-up-data. There were no significant differences between IA and PE in side effects (3.9% vs 3.6%, P = .96) or response-rate (P = .65). Responders showed significant lower age (P = .02) and earlier apheresis-initiation (P = .01). Subgroup-analysis confirmed significant lower age in patients with relapsing-remitting MS (RRMS) /clinical isolated syndrome (CIS).

CONCLUSION

IA and PE seem equally safe and effective in steroid-resistant MS- or NMO-relapses. Early apheresis and low patient age are additional prognostic factors.

Targeting B cells in the treatment of multiple sclerosis: recent advances and remaining challenges

Recent years have substantially broadened our view on the pathogenesis of multiple sclerosis (MS). While earlier concepts focused predominantly on T lymphocytes as the key cell type to mediate inflammatory damage within central nervous system (CNS) lesions, emerging evidence suggests that B lymphocytes may play a comparably important role both as precursors of antibody-secreting plasma cells and as antigen-presenting cells (APCs) for the activation of T cells. With greater appreciation of this pathogenic B-cell function in MS, B-cell-directed therapies, and in particular B-cell-depleting monoclonal antibodies targeting the CD20 molecule, have gained enormous interest over recent years. Clinical trials demonstrated that anti-CD20 treatment, which depletes immature and mature B cells but spares CD20 negative plasma cells, rapidly reduces formation of new inflammatory CNS lesions. While these findings clearly corroborate a pathogenic contribution of B cells, recent experimental but also clinical findings indicate that not all B cells contribute in an equally pathogenic manner and that certain subsets may in contrast mediate anti-inflammatory effects. In this review, we summarize current findings in support of pathogenic B-cell function in MS, including the encouraging clinical data which derived from anti-CD20 MS trials. Further, we review novel findings suggestive of regulatory properties of B-cell subsets which may be collaterally abolished by pan-CD20 depletion. In conclusion, we aim to provide an outlook on how this currently differentiating concept of pro- and anti-inflammatory B-cell function could be harnessed to further improve safety and effectiveness of B-cell-directed therapeutic approaches in MS.

Functional identification of pathogenic autoantibody responses in patients with multiple sclerosis

Pathological and clinical studies implicate antibody-dependent mechanisms in the immunopathogenesis of multiple sclerosis. We tested this hypothesis directly by investigating the ability of patient-derived immunoglobulins to mediate demyelination and axonal injury in vitro. Using a myelinating culture system, we developed a sensitive and reproducible bioassay to detect and quantify these effects and applied this to investigate the pathogenic potential of immunoglobulin G preparations obtained from patients with multiple sclerosis (n = 37), other neurological diseases (n = 10) and healthy control donors (n = 13). This identified complement-dependent demyelinating immunoglobulin G responses in approximately 30% of patients with multiple sclerosis, which in two cases was accompanied by significant complement-dependent antibody mediated axonal loss. No pathogenic immunoglobulin G responses were detected in patients with other neurological disease or healthy controls, indicating that the presence of these demyelinating/axopathic autoantibodies is specific for a subset of patients with multiple sclerosis. Immunofluorescence microscopy revealed immunoglobulin G preparations with demyelinating activity contained antibodies that specifically decorated the surface of myelinating oligodendrocytes and their contiguous myelin sheaths. No other binding was observed indicating that the response is restricted to autoantigens expressed by terminally differentiated myelinating oligodendrocytes. In conclusion, our study identifies axopathic and/or demyelinating autoantibody responses in a subset of patients with multiple sclerosis. This observation underlines the mechanistic heterogeneity of multiple sclerosis and provides a rational explanation why some patients benefit from antibody depleting treatments.

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.

Therapeutic plasma exchange for acute inflammatory demyelinating syndromes of the central nervous system

Idiopathic inflammatory demyelinating diseases (IIDDs) of the central nervous system, of which multiple sclerosis is the prototype, represent a family of monophasic, recurrent or progressive diseases with overlapping clinical and pathological manifestations. While most patients recover spontaneously or following a brief course of high-dose corticosteroids, occasional patients, particularly those with fulminant severe IIDDs, such as the Marburg variant, do not respond to corticosteroids and have severe, residual neurological deficits. While it is widely believed that IIDDs are mediated by T lymphocytes, as is experimental allergic encephelomyelitis, additional, possibly humoral, factors may be essential to generate the extensive demyelination seen in these conditions. Anecdotal reports over the past two decades have suggested that patients with acute, severe neurological deficits resulting from IIDDs, who fail to improve after high-dose intravenous corticosteroids, may benefit from plasma exchange. A randomized, sham-controlled, crossover study has recently been completed at the Mayo Clinic, which addresses these observations.

Multiple Sclerosis: Immunotherapy

Given our current knowledge, there is a need for the early institution of immunomodulatory therapy, especially for patients with poor prognostic factors (motor and cerebellar symptoms, frequent disease exacerbations, and a high level of activity on magnetic resonance imaging ). Patients who progress despite immunomodulatory therapy should be reevaluated in terms of diagnosis, development of neutralizing antibodies, or compliance. If a patient has a partial response to immunomodulatory therapy but his or her disease, as assessed by clinical and MRI criteria, remains very active, every effort should be made to modify disease progression by searching for an immunosuppressive therapy regimen before irreversible and considerable disability has accumulated. For the majority of patients, multiple sclerosis (MS) is a chronic condition. Therefore, until a curative treatment has been developed, the available repertoire of immunosuppressive or immunomodulatory treatments should be assessed with respect to the possibility of long-term use. This is particularly important for new immunosuppressive drugs, such as cladribine or mitoxantrone, or for invasive procedures, such as total lymphoid irradiation or autologous bone marrow transplantation. For the latter treatments, experience with long-term administration is not available or the potential side effects (eg, cardiotoxicity with mitoxantrone) limit the cumulative dose. These considerations may limit long-term administration and thus the general usefulness of some drugs. Even with proven efficacy, we need to define the next step once treatment has to be discontinued. We should also address whether exacerbating disease by discontinuing an effective therapy is a potential hazard. What other therapeutic options remain once the current treatment is discontinued? Answers are not readily available at the moment, but the question should influence our decisions in the selection of traditional, well-studied or new, potentially promising therapies.

Serum CD95 of relapsing remitting multiple sclerosis patients protects from CD95-mediated apoptosis

Failure of CD95-mediated apoptosis as a potential negative regulatory mechanism of T cell expansion may be involved in T cell-mediated autoimmune diseases such as multiple sclerosis (MS). Recently, soluble CD95 has been shown to be elevated in MS patients with active disease. Here, we report that the sera of MS patients inhibit CD95 ligand-induced apoptosis of susceptible target cells in a concentration-dependent manner and dependent on the amount of serum CD95 levels. Thus, MS sera contain biologically active inhibitors of T cell apoptosis that may allow for prolonged abnormal immune responses.

Rational clinical immunotherapy for multiple sclerosis

In this article, we assess the roles and the efficacy of immunopharmacologic agents in the treatment of multiple sclerosis (MS) and other demyelinating disease syndromes. The initial clinical manifestations of demyelinating disease, immunotherapeutic goals, efficacy of individual agents, and specific immunopharmacologic recommendations are discussed. MS and other idiopathic demyelinating disease syndromes can be effectively managed with immunotherapy. Exacerbations are treatable, and the frequency and severity of exacerbations can be reduced. Although some agents have a minor effect on progression of disability, current approaches have not proved to have a major influence on treatment of progressive MS. Immunotherapy for inflammatory demyelinating disease necessitates a high degree of clinical certainty about the diagnosis. Because all available therapeutic agents have limitations and significant toxic effects, careful consideration is necessary before use. Treatment should be individualized on the basis of the clinical course of the disease and the degree of patient disability.