Extracorporeal antibody elimination in neuroimmunological diseases

Extracorporeal procedures for the elimination of autoantibodies are an important therapeutic option in various neuroimmunological diseases, especially those with neuromuscular involvement. Recent advances with the development of selective apheresis methods have given extracorporeal therapeutic procedures a new perspective. In this article, we review the therapeutic use of plasma exchange and immunoadsorption therapy in different neuroimmunological diseases.

[Chronic inflammatory neuropathies]

INTRODUCTION

The group of chronic inflammatory neuropathies is made up of a variety of neuropathies of autoimmune or infectious origin.

DEVELOPMENT

We describe three types of neuropathies and their treatment: demyelinating chronic neuropathy, motor multifocal neuropathy and demyelinating neuropathy associated with monoclonal gammapathy. These three types of neuropathy have uniform characteristics and features, which permit precise identification and suggest that they are separate entities.

CONCLUSIONS

In the management of any type of neuropathy it is essential to make the correct diagnosis. Initial investigations should include detailed electrophysiological examination to detect the presence of demyelination, lumbar puncture and, if pleocytosis is found, the possibility of associated acquired immunodeficiency syndrome should be investigated. Also, before immunosuppressive treatment is begun, a systematic medical examination should be done to detect any other coexisting illness which might affect use of the different drugs involved.

Randomized trial of interferon beta-1a in chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVE

To test the safety and efficacy of interferon beta-1a (IFN-beta) in treatment-resistant chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

BACKGROUND

Current treatment regimens leave 4% to 30% of patients with CIDP with moderate or severe disability. IFN-beta has been reported as beneficial in one treatment-resistant patient.

METHODS

Ten consecutive treatment-resistant patients were randomized in a double-blind, crossover design to receive placebo or IFN-beta (3 MIU for 2 weeks and then 6 MIU for 10 weeks) subcutaneously three times weekly, followed by 4 weeks without treatment, and then the opposite treatment for 12 weeks. The primary outcome measure was "clinically important" improvement by specified amounts in any three of eight clinical measures: timed 10-m walk, Ambulation Index, expanded Medical Research Council sum score, nine-hole peg test time, Functional Independence Measure, Hammersmith Motor Ability, a new Guy's Neurological Disability Scale, and the EuroQoL quality-of-life scale. These and motor median nerve conduction studies were measured before and after 12 weeks of each treatment.

RESULTS

Clinically important improvement was observed in one patient while taking IFN-beta and two patients while taking placebo. There was no significant difference between IFN-beta and placebo in the change in any of the individual clinical or neurophysiological measures between the beginning and end of treatment. There were no serious adverse events.

CONCLUSION

This trial shows that IFN-beta is safe but not efficacious in treatment-resistant CIDP.

"Global" cell replacement is feasible via neural stem cell transplantation: evidence from the dysmyelinated shiverer mouse brain

Many diseases of the central nervous system (CNS), particularly those of genetic, metabolic, or infectious/inflammatory etiology, are characterized by "global" neural degeneration or dysfunction. Therapy might require widespread neural cell replacement, a challenge not regarded conventionally as amenable to neural transplantation. Mouse mutants characterized by CNS-wide white matter disease provide ideal models for testing the hypothesis that neural stem cell transplantation might compensate for defective neural cell types in neuropathologies requiring cell replacement throughout the brain. The oligodendrocytes of the dysmyelinated shiverer (shi) mouse are "globally" dysfunctional because they lack myelin basic protein (MBP) essential for effective myelination. Therapy, therefore, requires widespread replacement with MBP-expressing oligodendrocytes. Clonal neural stem cells transplanted at birth-using a simple intracerebroventricular implantation technique-resulted in widespread engraftment throughout the shi brain with repletion of MBP. Accordingly, of the many donor cells that differentiated into oligodendroglia-there appeared to be a shift in the fate of these multipotent cells toward an oligodendroglial fate-a subgroup myelinated up to 52% (mean = approximately 40%) of host neuronal processes with better compacted myelin of a thickness and periodicity more closely approximating normal. A number of recipient animals evinced decrement in their symptomatic tremor. Therefore, "global" neural cell replacement seems feasible for some CNS pathologies if cells with stem-like features are used.

Contrasting effects of anti-adhesion molecule therapy in experimental allergic encephalomyelitis and Theiler's murine encephalomyelitis

An augmentation of experimental allergic encephalomyelitis (EAE) was observed when monoclonal antibody (mAb) to intercellular adhesion molecule 1 (ICAM-1) was administered after adoptive transfer. Clinical disease was more severe in the ICAM-1 specific mAb-treated EAE mice and included prominent ataxia compared to the PBS-treated controls or Theiler's murine encephalomyelitis virus (TMEV) infected mice treated with ICAM-1 specific mAb. Neuropathologic evaluation demonstrated a distinctly different distribution of lesions in the anti-ICAM-1-treated EAE mice which featured prominent demyelination and inflammation in the cerebellum, brainstem and cerebrum. These structures were minimally involved in the control mice and mAb treatment did not alter the neuropathology in TMEV-infected mice. These results indicate that anti-ICAM-1 can alter trafficking of lymphocytes and mononuclear cells in EAE but not TMEV-induced demyelinating disease.

Upper limb predominant, multifocal chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) presents in rare instances with focal or multifocal upper limb involvement. We reviewed the clinical and electromyographic (EMG) characteristics of 10 such patients (UL-CIDP) and compared them with patients with typical generalized CIDP (G-CIDP) and multifocal motor neuropathy (MMN). There were six men and four women, with a mean age of 54 years. Symptoms began in one arm or hand in six patients and in both arms or hands in four and included numbness (n = 10), paresthesias (n = 9), weakness (n = 8), and pain (n = 6). Findings were initially restricted to the ulnar nerve distribution in three patients, and median and axillary nerve in one patient each, and involved multiple nerves in five. Conduction block was detected in the forearm segment of 68% of the median and ulnar motor nerves tested; in contrast to multifocal motor neuropathy, 73% of the sensory nerves tested were abnormal, and none had anti-GM1 antibodies. Aside from a regional onset, there were no clinical or electrophysiological features that distinguished patients with UL-CIDP from those with G-CIDP. However, the magnitude of recovery following treatment was greater in patients with G-CIDP. We conclude that a multifocal variant of CIDP begins with upper extremity sensorimotor symptoms, simulates isolated or multiple mononeuropathies, can be distinguished from MMN, and may have a less favorable response to treatment.

Mechanisms of high-dose intravenous immunoglobulins in demyelinating diseases

Administration of high-dose intravenous immunoglobulins has become one of the most successful new treatment regimens for demyelinating diseases. In a decade of molecular medicine, it came as a surprise that a natural blood product would prove effective in several disorders, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and, probably, multiple sclerosis. Many experimental studies, both in vivo and in vitro, have shown that intravenous immunoglobulins can interfere with the immune system at several levels. In addition, intravenous immunoglobulins may promote remyelination in demyelinating disease associated with viral infections. At present, no single mode of action has been identified as the crucial mechanism, which leads us to suggest that multiple effects may act in concert.

[Matrix metalloproteinases. Potential targets for new treatments in inflammatory demyelinating diseases of the nervous system]

Inflammatory demyelinating diseases of the nervous system, such as multiple sclerosis or the Guillain-Barré syndrome represent severely disabling disorders, often seen by the neurologist, with still only limited means for therapeutical intervention. The underlying pathomechanisms remain in large part elusive, however mounting evidence suggests that enzymes of the family of matrix metalloproteinases are of relevance in the pathogenesis of these disorders. Experimental in vivo data as well as results from other medical fields emphasize that the selective inhibition of these proteases could be a promising therapeutical approach. The following review summarizes the role of matrix metalloproteinases in inflammatory demyelinating diseases of the central as well as peripheral nervous system and discusses the therapeutical application of synthetic inhibitors in these disorders.

Multifocal acquired demyelinating sensory and motor neuropathy: the Lewis-Sumner syndrome

We report 11 patients with multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy, defined clinically by a multifocal pattern of motor and sensory loss, with nerve conduction studies showing conduction block and other features of demyelination. The clinical, laboratory, and histological features of these patients were contrasted with those of 16 patients with multifocal motor neuropathy (MMN). Eighty-two percent of MADSAM neuropathy patients had elevated protein concentrations in the cerebrospinal fluid, compared with 9% of the MMN patients (P < 0.001). No MADSAM neuropathy patient had elevated anti-GM1 antibody titers, compared with 56% of MMN patients (P < 0.01). In contrast to the subtle abnormalities described for MMN, MADSAM neuropathy patients had prominent demyelination on sensory nerve biopsies. Response to intravenous immunoglobulin treatment was similar in both groups (P = 1.0). Multifocal motor neuropathy patients typically do not respond to prednisone, but 3 of 6 MADSAM neuropathy patients improved with prednisone. MADSAM neuropathy more closely resembles chronic inflammatory demyelinating polyneuropathy and probably represents an asymmetrical variant. Given their different clinical patterns and responses to treatment, it is important to distinguish between MADSAM neuropathy and MMN.

Peripheral neuropathy associated with anti-myelin basic protein antibodies in a woman vaccinated with rubella virus vaccine

Active immunisation with rubella vaccine has not been commonly associated with neurological complications. We report the case of a 23-year-old woman who developed a mild, distal demyelinating neuropathy after immunisation with the live attenuated RA 27/3 rubella strain. Post-immunisation immunologic studies carried over 24 months showed the presence of antibodies to the RV proteins, particularly to the capsid antigen, and to the myelin basic protein (MBP). A similarity between a C antigen motif and a sequence of the MBP was found by computer analysis. The cross-reactivity was confirmed by immunising mice with a synthetic peptide derived from the MBP, which developed a strong humoral response to RV and MBP. This finding raises the possibility that a virus-induced immune response could lead to an autoaggressive reaction responsible for demyelination.

Clinical features and anti-neural reactivity in neuropathy associated with IgG monoclonal gammopathy of undetermined significance

Neuropathy has been frequently reported in patients with IgG monoclonal gammopathy of undetermined significance (MGUS) but it is still unclear whether this association has clinical or pathogenetic relevance. In order to clarify the possible role of IgG MGUS in the neuropathy we correlated the clinical and electrophysiological features of the neuropathy with the duration and anti-neural activity of the M-protein in 17 patients with neuropathy and IgG MGUS. Ten patients (59%) had a chronic demyelinating neuropathy clinically indistinguishable from chronic inflammatory demyelinating polyneuropathy (CIDP) while 7 (41%) had a predominantly sensory axonal or mixed neuropathy. In 80% of patients in the CIDP-like and 28% in the sensory group the IgG M-protein became manifest several months to years after onset of the neuropathy. Antibodies to one or more neural antigens (including tubulin, a 35KD P0-like nerve myelin glycoprotein, GD1a, GM1 and chondrotin sulfate C) were found in 40% of patients with CIDP-like and 43% with sensory neuropathy but also in 37% patients with IgG MGUS without neuropathy. Neuropathy associated with IgG MGUS is probably less heterogeneous than previously considered suggesting that this association may not be merely casual. The evidence for primary pathogenetic role of IgG M-proteins in the neuropathy remains however elusive.

Variability in the binding of anti-MAG and anti-SGPG antibodies to target antigens in demyelinating neuropathy and IgM paraproteinemia

Densitometry of immunostained Western blots or thin layer chromatograms and enzyme-linked immunosorbent assays (ELISAs) were used to compare the relative strengths of IgM binding to myelin-associated glycoprotein (MAG), P0 glycoprotein, peripheral myelin protein-22 (PMP-22), sulfate-3-glucuronyl paragloboside (SGPG), and other potential target antigens in a series of eleven patients with sensory or sensorimotor demyelinating neuropathy and IgM paraproteinemia. The IgM from all patients exhibited reactivity with both MAG and SGPG, and there was a statistically significant correlation between the overlay assays and ELISAs for measuring the strength of IgM binding to MAG and to SGPG. However, the data revealed variations in the relative strengths with which the antibodies bound to the potential target antigens and heterogeneity in their fine specificities. First, there was a poor correlation between the strength of binding to MAG and to SGPG, respectively. Second, reactivity with MAG or SGPG in a few of the patients was only detected by one of the two assay systems. Third, about one-third of the patients' IgM absolutely required the sulfate on SGPG for reactivity, whereas the others retained some reactivity after removal of the sulfate. Fourth, IgM from two of the patients exhibited unusually strong reactivity with the proteins of compact myelin, P0 and PMP22. These relative differences in strengths of antibody binding to the potential antigens were compared with the patients' clinical presentations and with their responses to intravenous immunoglobulin (IVIg) therapy in a clinical trial in which they participated. For the most part, these variations did not correlate with clinical presentation, which was relatively homogeneous in this series of patients. However, an inverse relationship was noted between degree of reactivity to MAG by ELISA and response to IVIg. Two of the patients who responded had only mild elevations of IgM antibodies to nerve glycoconjugates and exhibited some unusual immunochemical and clinical characteristics in comparison to the other patients. The results demonstrate differences in the relative strengths with which anti-MAG and anti-SGPG IgM antibodies from different patients bind to potential neural target antigens which may affect pathogenic mechanisms and response to therapy.

Nasal administration of recombinant rat IL-4 ameliorates ongoing experimental autoimmune neuritis and inhibits demyelination

Experimental autoimmune neuritis (EAN) is a CD4(+)T cell-mediated demyelinating disease of the peripheral nervous system (PNS) and serves as an experimental model for human immune-demyelinating neuropathies. In this study, we examined the effect of recombinant rat interleukin-4 (rrIL-4) on chronic EAN in Lewis rats induced by immunization with P0 peptide 180-199 and complete Freund's adjuvant (CFA). We estimated that nasal administration of rrIL-4, in dose ranges of 0.1-1 microg/rat/day in the initial phase of EAN, decreased the severity and the duration of clinical EAN. Hyporesponsiveness of T cells, downregulation of Th1 cell responses (INF-gamma), but increased levels of specific IgG1 isotypes document that nasal administration of rrIL-4 was systemically immune effective. Low grade inflammation and complete lack of regional demyelination within the sciatic nerves were seen in rrIL-4 treated rats. Based on these observations we suggest that nasal administration of IL-4 could be further evaluated, considering its possible use in human immune-demyelinating neuropathies.

Treatment of chronic dysimmune polyneuropathies

Chronic dysimmune neuropathies are less common than Guillain-Barré syndrome (GBS). They mainly comprise chronic idiopathic demyelinating polyneuropathy (CIDP), multifocal motor neuropathy with persistent conduction blocks (MMNCB) and polyneuropathy associated with monoclonal gammopathy. However, as GBS, they are considered to be immune-mediated disorders and they may respond to various immunosuppressive treatments, such as corticosteroids, plasma exchanges (PE) or intravenous immunoglobulins (IVIg). The first step is to characterize these neuropathies on clinical, electrophysiological and sometimes immunochemical criteria, because the response to treatment may be different according to the type of neuropathy. For example, polyneuropathy associated with IgM monoclonal gammopathy does not respond to steroids and MMNCB may worsen under PE, while CIDP may respond either to steroids, PE or IVIg. The second step is to choose the type and the regimen of the treatment. Some neurological conditions may require only short-term therapy, for example in relapsing CIDP, whereas other conditions may require long-term therapy.

[The clinical usefulness of high-dose intravenous immunoglobulin therapy for chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy]

To explore the optimum dose of intravenous immunoglobulin (i.v.Ig) for treating patients with chronic inflammatory demyelinating polyrneuropathy and multifocal motor neuropathy, we compared the usefulness of i.v.Ig among 3 treatment doses. Fifty-nine patients were randomly divided into three treatment dosage groups: 20 patients for Group I using 50 mg/kg/day x 5 days, 19 patients Group II using 200 mg/kg/day x 5 days, and 20 patients Group III using 400 mg/kg/day x 5 days. We assessed clinically and electrophysiologically the effectiveness of the treatment at 5 weeks after the initial infusion. For patients in Group I and II who had not improved (or worsened) with the first treatment, we gave a one-step larger dose in the second treatment (i.e. 200 mg/kg/day x 5 days for those who had been given 50 mg/kg/day x 5 days, 400 mg/kg/day x 5 days for those who had been given 200 mg/kg/day x 5 days) after more than 9 weeks. We found that 15% of the patients in Group I, 21% in Group II and 60% in Group III improved dose-dependently with the first intravenous immunoglobulin treatment. Seven (47%) of 16 patients in Group I and 4 (40%) of 11 patients in Group II improved after the second treatment with larger doses. Adverse reactions including chill sensation, fever, skin eruption and increase in blood GOT and GPT levels were transient and mild. One patient in Group III developed left hemiparesis showing the small infarction in the right thalamus during the course of the treatment, but the symptom was mild. In conclusion, the high-dose intravenous immunoglobulin therapy (400 mg/kg/day x 5 days) is useful for treating patients with CIDP and MMN, although care must be taken of the risk of causing cerebral infarctions.

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[Marchiafava-Bignami disease. 3 cases with favorable prognosis]

INTRODUCTION

Marchiafava-Bignami disease is a complication of chronic alcoholism, with acute or subacute demyelination of the corpus callosum. Although subacute and benign forms of the disease have been described since the development of CT scan and MRI, it has usually a poor prognosis.

EXEGESIS

We report three cases of Marchiafava-Bignami disease with favorable outcome. One of the patient was comatose upon hospital admission. Interhemispheric dysconnection syndrome was evidenced in two patients. CT scan and MRI showed lesions extending to the callosal white matter in these patients.

CONCLUSION

Potential existence of Marchiafava-Bignami disease should be investigated in patients presenting with chronic alcoholism and mental confusion. However, accompanying coma and white matter demyelination should not necessarily be considered of poor prognosis. Clinical evaluation of interhemispheric dysconnection is of value in patients presenting with chronic alcoholism and mental confusion.

Chronic steadily progressive central and peripheral predominantly motor demyelination, involving the cranial nerves, responsive to immunoglobulins

The association of central and peripheral demyelination was reported previously. Most of the cases refer to central chronic relapsing demyelination with clinical criteria for multiple sclerosis associated with later signs of peripheral nerve involvement. Other authors, described central lesions in patients with chronic inflammatory demyelinating polyneuropathy and in Guillain-Barré syndrome, as a seldom occurrence. We report a patient in which a chronic steadily progressive central and peripheral predominantly motor nervous system demyelination, involving the cranial nerves, was identified. The patient improved after intravenous immunoglobulin suggesting an immune-mediated mechanism. To our knowledge this presentation was not described before.

Plasma-exchange in chronic peripheral neurological disorders

We investigated 19 patients affected by chronic peripheral neurological disorders treated with therapeutic plasma exchange (TPE) to verify the efficacy of the therapeutic protocol used in these diseases. Every patient was clinically considered after 5 TPE. Those who showed an improvement started chemotherapy and continued TPE at the rate of 2 procedures/week for 2 weeks, then 1 procedure/week for 1 month and finally 1 procedure every 2 weeks for 2 months. Intravenous immunoglobulins (IVIg) were infused at the end of apheretic treatment in one of the patients affected by neurological disorders due to monoclonal gammopathy undetermined significance. HCV-positive patients with cryoglobulins were treated with alpha-interferon (alpha-IFN) for 6 months before TPE. Eleven patients (58%) had a symptomatic improvement, 2 (1.5%) stopped TPE treatment owing to side effects and 6 (31.5%) did not respond to apheretic therapy. In order to improve the advantages of TPE we suggest using IVIg at the end of apheretic therapy, while in HCV-positive patients, at least one year of alpha-IFN therapy is required before initiating TPE.