Viral hyperinfection of the central nervous system and high mortality after hematopoietic stem cell transplantation for treatment of Theiler's murine encephalomyelitis virus-induced demyelinating disease

Theiler's murine encephalomyelitis virus (TMEV) establishes a persistent infection in the central nervous system (CNS) leading to an inflammatory demyelinating disease of the CNS in which the histology and clinical course is similar to multiple sclerosis (MS). Disease pathogenesis is primarily due to T-cell-mediated destruction of myelin, which has been attributed to cytopathic effects of the virus, but immune-mediated destruction of myelin mediated via both virus-specific and myelin-specific T cells appear to play the major role. To determine if bone marrow transplantation would be an effective therapy for a virus-initiated autoimmune disease and to better separate viral cytopathic effects from immune-mediated demyelination, we ablated the immune system of TMEV-infected animals with 1,100 cGy total body irradiation, and then the animal's immunity was reconstituted by transplantation of disease-susceptible SJL/J mice with syngeneic marrow or disease-susceptible DBA/2J with marrow from disease-resistant (C57Bl/6 x DBA/2)F1 (B6D2) donors. Hematopoietic transplant performed after onset of disease resulted in 42% mortality in SJL/J syngeneic transplants, 47% mortality in diseased DBA2 recipients restored with marrow from naive B6D2 donors, and 12% in diseased DBA2 recipients receiving marrow from B6D2 donors previously infected with TMEV. Delayed type hypersensitivity (DTH) to both virion and myelin proteins was decreased in surviving mice that underwent transplantation; however, CNS viral titers were significantly elevated compared with nontransplanted controls. We conclude that a functional immune system with appropriate T-cell responses are important in prevention of lethal cytopathic CNS effects from TMEV. Relevant to the clinical use of bone marrow transplantation, attempts to ablate the immune system in viral-mediated immune diseases or virus-initiated autoimmune disease may have acute and lethal consequences. Our results raise concern about the attempted use of autologous hematopoietic transplantation in patients with MS, an autoimmune disease with a suspected virus etiology, particularly if the graft is aggressively depleted of lymphocytes.

Therapeutic plasma exchange: an update from the Canadian Apheresis Group

In 1997, the Canadian Apheresis Group reviewed data on 103,416 plasma exchange procedures that had been collected since 1980. Although the number of plasma exchanges gradually increased (from 3189 to 8208 per year), the pattern changed. In 1981, the five most frequent indications for plasma exchange resulted in 55% of all such procedures; by 1997, the five most frequent indications for plasma exchange resulted in 81.1% of all such procedures. During this period, three conditions that were originally among the most frequent indications for plasma exchange became among the least frequent. This paper reviews the published evidence that supports or refutes the use of plasma exchange in the category of the five most frequent indications from 1981 to 1997: thrombotic thrombocytopenic purpura, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, Waldenstrom macroglobulinemia, the Guillain-Barre syndrome, rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. For most disorders, use of plasma exchange procedures is correlated with published evidence, and the changing patterns of plasma exchange use by members of the Canadian Apheresis Group reflect published evidence. Annual center-by-center reviews of use of plasma exchange may also have influenced practice patterns.

Immunoadsorption in multifocal motor neuropathy

To our knowledge, this is the first reported application of immunoadsorption in a patient with multifocal motor neuropathy (MMN). The diagnosis relied on the typical clinical features, markedly increased IgM-GM1 antibodies, multiple motor conduction blocks, and motor nerve biopsy. Immunoadsorption was carried out in seven cycles of two sessions each within 97 days. From the first therapy, muscle force as well as nerve conduction velocity and conduction blocks deteriorated continuously. As a consequence, immunoadsorption cannot be recommended as a treatment for MMN.

Enhanced axonal regeneration following combined demyelination plus schwann cell transplantation therapy in the injured adult spinal cord

We have treated spinal cord injured rats with demyelination plus Schwann cell transplantation and assessed neurite outgrowth in a quantifiable model of axonal regeneration. Axonal injuries of differing severity were induced in the dorsal funiculus of adult rats using a micromanipulator-controlled Scouten knife. Demyelinated regions were produced so as to overlap with the injury site by the injection of galactocerebroside antibodies plus complement one segment cranial to the axonal injury site. Schwann cells were isolated from the sciatic nerve, expanded in vitro, and transplanted into the injury site 1 day later. Animals were killed after an additional 7 days. Schwann cells were evenly distributed throughout the region of demyelination, which extended 6-7 mm cranial to the axonal injury site. The severity of axonal injury was quantified by counting degenerate axons in transverse resin sections. The degree of axonal regeneration was assessed by an electron microscopic analysis of growth cone frequency and distribution relative to the site of axonal injury. Quantification of growth cones at a distance from the site of axonal injury indicated a strong linear relationship (P < 0.001) between the number of growth cones and the number of severed axons; the ratio of growth cones to severed axons was increased by 26.5% in demyelinated plus transplanted animals compared to demyelinated animals without a transplant. Furthermore, only the demyelinated plus transplanted animals contained growth cones associated with myelin in white matter immediately outside of the region of complete demyelination. Growth cones were absent in transplanted-only animals at a distance from the site of axonal injury. These findings indicate that combined demyelination plus Schwann cell transplantation therapy enhances axonal regeneration following injury and suggests that growth cones are able to overcome myelin-associated inhibitors of neurite outgrowth in the presence of trophic support.

[The immunosorption of the cerebrospinal fluid in the treatment of inflammatory demyelinating polyneuropathies]

Immunosorption of cerebrospinal fluid with updated "Pall" immunofilters (Germany) was successfully performed in 3 patients with progressing hormone-resistant Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy. It was proved that clinical improvement in the patients' state correlated with a decrease in the contents of both total protein and immunoglobulins G, A, M in cerebrospinal fluid. It was suggested that the removal of these humoral factors had decreased a degree of inflammatory and demyelinating processes in inflammatory demyelinating polyneuropathies and had improved, thereby, the results of the treatment.

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.