Inflammatory infiltrates in sural nerve biopsies in Guillain-Barre syndrome and chronic inflammatory demyelinating neuropathy

The Guillain-Barré syndrome

The latest estimation for the frequency of Guillain-Barré syndrome (GBS) is 1.1 to 1.8 per 100000 persons per year. Guillain-Barré syndrome is today divided into two major subtypes: acute inflammatory demyelinating polyneuropathy (AIDP) and the axonal subtypes, acute motor axonal neuropathy (AMAN) and acute motor and sensory axonal neuropathy (AMSAN). The axonal forms of GBS are caused by certain autoimmune mechanisms, due to a molecular mimicry between antecedent bacterial infection (particularly Campylobacter jejuni) and human peripheral nerve gangliosides. Improvements in patient management in intensive care units has permitted a dramatic drop in mortality rates. Immunotherapy, including plasma exchange (PE) or intravenous immunoglobulin (IVIg), seems to shorten the time to recovery, but their effect remains limited. Further clinical investigations are needed to assess the effect of PE or IVIg on the GBS patients with mild affection, no response, or relapse.

Chronic inflammatory demyelinating polyradiculoneuropathy: from bench to bedside

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common treatable chronic autoimmune neuropathy. Multiple diagnostic criteria have been established, with the primary goal of identifying neurophysiologic hallmarks of acquired demyelination. Treatment modalities have expanded to include numerous immunomodulatory therapies, although the best evidence continues to be for corticosteroids, plasma exchange, and intravenous immunoglobulin (IVIg). This review describes the pathology, epidemiology, pathogenesis, diagnosis, and treatment of CIDP.

Colony-stimulating factor-1 mediates macrophage-related neural damage in a model for Charcot-Marie-Tooth disease type 1X

Previous studies in our laboratory have shown that in models for three distinct forms of the inherited and incurable nerve disorder, Charcot-Marie-Tooth neuropathy, low-grade inflammation implicating phagocytosing macrophages mediates demyelination and perturbation of axons. In the present study, we focus on colony-stimulating factor-1, a cytokine implicated in macrophage differentiation, activation and proliferation and fostering neural damage in a model for Charcot-Marie-Tooth neuropathy 1B. By crossbreeding a model for the X-linked form of Charcot-Marie-Tooth neuropathy with osteopetrotic mice, a spontaneous null mutant for colony-stimulating factor-1, we demonstrate a robust and persistent amelioration of demyelination and axon perturbation. Furthermore, functionally important domains of the peripheral nervous system, such as juxtaparanodes and presynaptic terminals, were preserved in the absence of colony-stimulating factor-1-dependent macrophage activation. As opposed to other Schwann cell-derived cytokines, colony-stimulating factor-1 is expressed by endoneurial fibroblasts, as revealed by in situ hybridization, immunocytochemistry and detection of β-galactosidase expression driven by the colony-stimulating factor-1 promoter. By both light and electron microscopic studies, we detected extended cell-cell contacts between the colony-stimulating factor-1-expressing fibroblasts and endoneurial macrophages as a putative prerequisite for the effective and constant activation of macrophages by fibroblasts in the chronically diseased nerve. Interestingly, in human biopsies from patients with Charcot-Marie-Tooth type 1, we also found frequent cell-cell contacts between macrophages and endoneurial fibroblasts and identified the latter as main source for colony-stimulating factor-1. Therefore, our study provides strong evidence for a similarly pathogenic role of colony-stimulating factor-1 in genetically mediated demyelination in mice and Charcot-Marie-Tooth type 1 disease in humans. Thus, colony-stimulating factor-1 or its cognate receptor are promising target molecules for treating the detrimental, low-grade inflammation of several inherited neuropathies in humans.

Nerve biopsy in chronic inflammatory neuropathies: in situ biomarkers

We collected the evidence for potential biomarkers in nerve biopsies that might be of use in diagnosis, assessment, or treatment response in chronic inflammatory demyelinating polyneuropathies (CIDPs). We performed a literature search in PubMed from 1965 to May 2010 using the key words (["chronic inflammatory polyneuropathy" or "polyradiculoneuritis" or {"chronic and neuritis"}] and "nerve biopsy") and searched manually within these references for relevant publications related to the subject. Twenty references gave information about potential biomarkers for CIDP. Evidence of demyelination alone is not specific for CIDP, but may support the diagnosis in the context of a typical clinical pattern. Although the total numbers of inflammatory cells do not distinguish well between CIDP and non-inflammatory neuropathies, the pattern of macrophage clusters around endoneurial vessels may be a simple marker of inflammation with good sensitivity and specificity. Immunohistochemistry for matrix metalloproteinase-9 may be useful for the distinction of inflammatory and non-inflammatory neuropathies. Microarrays which give a complex pattern of up- and downregulated genes also show promise for developing a biomarker. Immunohistochemistry on sural nerve biopsies has the potential to distinguish inflammatory from non-inflammatory neuropathies. More research is needed to establish the diagnostic validity of specific markers and of gene expression studies and to test whether they can distinguish between subtypes of inflammatory neuropathies.

Vasculitis-like neuropathy in amyotrophic lateral sclerosis unresponsive to treatment

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease with variable involvement of other systems. A pathogenetic role of immune-mediated mechanisms has been suggested. We retrospectively analyzed sural nerve pathology and the clinical course in 18 patients with ALS. These patients had undergone sural nerve biopsy because of clinical or neurophysiological signs indicating sensory involvement (ALS+). Eleven of the 18 ALS+ patients had inflammatory cell infiltrates (ALS(vasc)) resembling infiltrates seen in patients with vasculitic neuropathy. Data were compared with the 7 patients without vasculitic infiltrates (ALS(nonvasc)) and with those of 16 patients with isolated peripheral nerve vasculitis (NP(vasc)). Biopsy specimens were processed with standard histological stains and with immunohistochemistry for a panel of inflammatory markers, with the hypothesis that the composition of infiltrates should differ between ALS(vasc) and NP(vasc). Immunoreactive cells were quantified in a blinded manner. Unlike patients with NP(vasc), those with ALS(vasc) had only minor neurophysiological abnormalities in the sural nerve and, except for the infiltrates, almost normal nerve morphology on semithin sections. The difference in epineurial T cell count was significant between ALS(vasc) and ALS(nonvasc) (p = 0.031). Surprisingly, the cellular composition of epineurial infiltrates in sural nerve biopsies was indistinguishable between ALS(vasc) and NP(vasc) despite a significant difference in fiber pathology (p < 0.0001). Standard immunosuppressive treatment did not prevent clinical progression of the motor neuron disease in any of the patients with ALS(vasc). ALS(vasc) appears as a neuropathological subtype in ALS+ suggesting immune-mediated disease components but without response to standard immunosuppressive treatment.

Pathogenesis and treatment of immune-mediated neuropathies

Immune-mediated neuropathies represent a heterogeneous spectrum of peripheral nerve disorders that can be classified according to time course, predominant involvement of motor/sensory fibers, distribution of deficits and paraclinical parameters such as electrophysiology and serum antibodies. In the last few years, significant advances have been achieved in elucidating underlying pathomechanisms, which made it possible to identify potential therapeutic targets. In this review, we discuss the latest development in pathogenesis and treatment of immune-mediated neuropathies.

Autoimmune diseases of the peripheral nervous system

Autoimmune-mediated diseases targeting the peripheral nerve represent a group of disorders often associated with high clinical disability. At present, therapeutic options are limited. The application of innovative and cutting-edge technologies to the study of immune-mediated disorders of the peripheral nervous system (PNS) have generated a better understanding of underlying principles of the organization of the immune network present in the peripheral nerve and its dialogue with the systemic immune system. These insights may foster the development of specific and highly effective therapies for autoimmune diseases of the peripheral nerve. Of great interest in this context is the application of monoclonal antibodies, such as rituximab or alemtuzumab, which in small observational studies provided promising clinical results. But also other immunomodulatory or immunosuppressive drugs used in other indications currently find their way to PNS autoimmunity. Clearly, prospective controlled clinical trials are warranted before making firm conclusions on the feasibility of these innovative therapeutic approaches for treating immune-mediated disease of the peripheral nerve.

Distinct cytokine patterns associated with different forms of chronic dysimmune neuropathy

To better understand the presumed immune system dysregulation of chronic dysimmune neuropathy (CDN) patients, we designed a study to evaluate the levels of pro- and anti-inflammatory cytokines in the most common forms of CDN: chronic inflammatory demyelinating polyneuropathy (CIDP), and anti-myelin-associated glycoprotein (MAG)-related polyneuropathy (MAGnp). Sixteen patients fulfilled diagnostic criteria for CIDP, 14 were diagnosed with MAGnp, and 36 were classified as exhibiting "chronic idiopathic polyneuropathy" (CIP). Cytokine production in mitogen-stimulated peripheral blood mononuclear cells (PBMCs) was analyzed by flow cytometry. CIDP and MAGnp patients were compared with CIP patients, those with monoclonal gammopathy without polyneuropathy (MGUS), and healthy controls (HC). We observed an increase in pro-inflammatory cytokines in the CIDP group, whereas interleukin-10 (IL-10) was augmented in the MAGnp patients. These distinctive immune alterations may represent a biological tool in differential diagnosis and future therapeutic approaches.

Plasma exchange and intravenous immunoglobulins: mechanism of action in immune-mediated neuropathies

Immune-mediated neuropathies are a heterogeneous group of peripheral nerve disorders, which are classified by time course, clinical pattern, affected nerves and pathological features. Plasma exchange (PE) and intravenous immunoglobulins (IVIg) are mainstays in the treatment of immune-mediated neuropathies. Of all treatments currently used, IVIg has probably the widest application range in immune-mediated neuropathies and efficacy has been well documented in several randomized controlled trials for Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP). Beneficial effects of IVIg have also been proven for multifocal motor neuropathy (MMN). Likewise, PE is an established treatment for GBS and CIDP, whereas it is considered to be ineffective in MMN. Different mechanisms of action are sought to be responsible for the immunemodulatory effect of PE and IVIg in autoimmune disorders. Some of those might be important for immune-mediated neuropathies, while others are probably negligible. The aim of this review is to summarize the recent advances in elucidating disease-specific mechanisms of actions of PE and IVIg in the treatment of immune-mediated neuropathies.

Correlation of matrix metalloproteinases-2 and -9 with proinflammatory cytokines in Guillain-Barré syndrome

The role of matrix metalloproteinases (MMPs) and cytokines in the pathogenesis of Guillain-Barré syndrome (GBS) largely remains unknown. We studied the role of MMP-2, MMP-9, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in disease progression and recovery of patients with GBS. Sixty-five patients with GBS and 68 healthy controls were enrolled in the study. Serum levels of MMP-2, MMP-9, TNF-α, and IL-1β were analyzed by ELISA, and activities of MMPs were measured by zymography. Expression of MMP-9, TNF-α, and IL-1β was higher in the progressive phase and lower in the recovery phase of GBS than in controls. A positive correlation of MMP-2 with IL-1β and MMP-9 with TNF-α and IL-1β was observed with progressive-phase GBS. The study shows that up-regulation of MMP-9 along with proinflammatory cytokines (TNF-α and IL-1β) in the early course appears to be associated with immune-mediated disease progression resulting from inflammation in the peripheral nervous system, whereas, during the later phase, down-regulation of MMP-9 and proinflammatory cytokines is implicated in recovery from the disease.

Skin biopsy as an additional diagnostic tool in non-systemic vasculitic neuropathy

Sural nerve biopsy is considered mandatory for diagnosing non-systemic vasculitic neuropathy (NSVN). This invasive technique may be associated with unpleasant sequelae and cannot easily be repeated. Skin punch biopsy from an affected area may be a less invasive and repeatable diagnostic method. Here we assessed the potential diagnostic value of skin punch biopsies in NSVN by analyzing skin biopsies in 20 patients with sural nerve biopsy-proven NSVN and in 11 patients with non-inflammatory axonal neuropathy. As further controls, skin biopsies were studied in nine healthy volunteers. Five millimeter skin punch biopsies were taken under local anesthesia from the distal lateral calf and T cells and macrophages were quantified after immunostaining. The diagnostic sensitivity and specificity compared to sural nerve biopsy was determined using receiver operating characteristic (ROC) analysis. ROC analysis revealed that the highest sensitivity (94%) and specificity (79%) for NSVN was obtained when perivascular macrophages were quantified. Quantification of scattered T cells yielded a sensitivity and specificity of 65%. Inflammatory cells were very rare in controls. Quantification of inflammatory cells in skin biopsies may thus be a sensitive and specific additional tool for diagnosing NSVN.

Expression of antigen processing and presenting molecules by Schwann cells in inflammatory neuropathies

Schwann cells are the myelinating glia cells of the peripheral nervous system (PNS) and can become targets of an autoimmune response in inflammatory neuropathies like the Guillain-Barré syndrome (GBS). Professional antigen presenting cells (APCs) are known to promote autoimmune responses in target tissues by presenting self-antigens. Other cell types could participate in local autoimmune responses by acting as nonprofessional APCs. Using a combined approach of immunocytochemistry, immunohistochemistry, and flow cytometry analysis we demonstrate that human Schwann cells express the antigen processing and presenting machinery (APM) in vitro and in vivo. Moreover, cultured human Schwann cells increase the expression of proteasome subunit delta (Y), antigen peptide transporter TAP2, and HLA Class I and HLA Class II complexes in an inflammatory environment. In correlation with this observation, Schwann cells in sural nerve biopsies from GBS patients show increased expression of antigen processing and presenting molecules. Furthermore, cultured human Schwann cells can proteolytically digest fluorescently-labeled nonmammalian antigen ovalbumin. Taken together, our data suggest antigen processing and presentation as a possible function of Schwann cells that may contribute to (auto)immune responses within peripheral nerves.

Mouse Schwann cells activate MHC class I and II restricted T-cell responses, but require external peptide processing for MHC class II presentation

Schwann cells are the myelinating glia cells of the peripheral nervous system (PNS). In inflammatory neuropathies like the Guillain-Barré syndrome (GBS) Schwann cells become target of an autoimmune response, but may also modulate local inflammation. Here, we tested the functional relevance of Schwann cell derived MHC expression in an in vitro coculture system. Mouse Schwann cells activated proliferation of ovalbumin specific CD8+ T cells when ovalbumin protein or MHC class I restricted ovalbumin peptide (Ova(257-264) SIINFEKL) was added and after transfection with an ovalbumin coding vector. Schwann cells activated proliferation of ovalbumin specific CD4+ T cells in the presence of MHC class II restricted ovalbumin peptide (Ova(323-339) ISQAVHAAHAEINEAGR). CD4+ T-cell proliferation was not activated by ovalbumin protein or transfection with an ovalbumin coding vector. This indicates that Schwann cells express functionally active MHC class I and II molecules. In this study, however, Schwann cells lacked the ability to process exogenous antigen or cross-present endogenous antigen into the MHC class II presentation pathway. Thus, antigen presentation may be a pathological function of Schwann cells exacerbating nerve damage in inflammatory neuropathies.

pSTAT1, pSTAT3, and T-bet as markers of disease activity in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is considered an auto-immune disorder. We evaluated expression of pSTAT1, T-bet, and pSTAT3 in circulating T-cells, B-cells, and monocytes and spontaneous production of interleukin-17 (IL17), interferon-gamma (IFN gamma), and interleukin-10 (IL10) by peripheral blood mononuclear cells (PBMCs) from 14 active CIDP patients compared with 6 patients with long-lasting remission and 20 controls. Active disease patients showed higher pSTAT1, T-bet, and pSTAT3 in CD4(+) T-cells than controls (p < 0.001, p = 0.0002, p = 0.0097, respectively) and remission patients (p < 0.001, p = 0.0036, p = 0.0008, respectively). pSTAT1, T-bet, and pSTAT3 were also higher in monocytes from active CIDP patients than controls (p = 0.0011, p = 0.0041, p = 0.0413, respectively) and remission patients (p = 0.0073, p = 0.0274, p = 0.0251, respectively). Moreover in CD8(+) T-cells, pSTAT3 expression was higher in active CIDP patients than in remission patients (p = 0.0345) and in controls (p = 0.0023). IL17 and IFN gamma production were significantly higher in active CIDP patients than in controls (p < 0.0395, p = 0.0010, respectively); IFN gamma levels were higher also in remission CIDP patients (p = 0.0073). IL10 levels were higher in active phase patients than in controls (p = 0.0334). Our data suggest that pSTAT1, T-bet, and pSTAT3 can be considered putative markers of disease activity and potential targets for specific therapies.

[The significance of intravenous immunoglobulin in treatment of immune-mediated polyneuropathies]

Long-term treatment of immune-mediated polyneuropathies remains difficult. For acute polyneuritis, or Guillain-Barré syndrome, the established standard therapy utilizes high doses of polyvalent intravenous immunoglobulins (IVIG). A recently published randomized placebo-controlled study of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) showed IVIG to be clinically effective also for this disorder in both short and long term. This survey presents data of this so-called ICE study ("Intravenous immune globulin for the treatment of chronic inflammatory demyelinating polyradiculoneuropathy"). It also discusses the value of IVIG in the treatment of immune-mediated polyneuropathies.

Intravenous immunoglobulins in the treatment of immune neuropathies

PURPOSE OF REVIEW

The aim of this review is to describe the value of high-dose polyclonal intravenous immunoglobulins as a treatment option in autoimmune disorders affecting the peripheral nervous system.

RECENT FINDINGS

A randomized placebo-controlled trial in patients with chronic inflammatory demyelinating polyradiculoneuropathy revealed short-term and long-term efficacy and safety of intravenous immunoglobulins as a treatment option for the chronically inflamed peripheral nervous system. Case reports suggest that the subcutaneous administration of immunoglobulins may represent a convenient alternative.

SUMMARY

Intravenous immunoglobulin represents an effective and safe treatment option in patients with autoimmune-mediated diseases affecting the peripheral nerves.

Immune circuitry in the peripheral nervous system

PURPOSE OF REVIEW

The aim of this review is to describe the local immune circuitry in the peripheral nervous system and its dialogue with systemic immunity under pathological conditions. Specifically, interactions of the immune system with cellular and extracellular components within peripheral nerve and immune functions of tissue-resident endoneurial macrophages and Schwann cells will be discussed.

RECENT FINDINGS

New insights into the elements involved in the pathogenesis of immune-mediated disorders of the peripheral nervous system provide a better understanding of the complex interplay of these cellular and molecular components in the immunology of the peripheral nervous system.

SUMMARY

The application of innovative and cutting-edge technologies to the study of immunoinflammatory disorders of the peripheral nervous system provides a better understanding of underlying principles of the organization of the immune network present in the peripheral nerve and its dialogue with the systemic immune system. This may foster the development of specific and highly effective therapies for immune-mediated disorders of the peripheral nerve.

Reduced circulating CD4+CD25+ cell populations in Guillain–Barré syndrome

Guillain-Barré syndrome (GBS) is a monophasic inflammatory disease considered to be due to autoimmunity. In order to test the hypothesis that the disease is associated with a perturbation of the circulating lymphoid cell population, we tested the mononuclear cells from the venous blood of 21 patients with Guillain-Barré syndrome (GBS) and 20 healthy controls by flow cytometry. The proportions and numbers of B and T lymphocytes, and CD4, CD8, double negative and gammadelta T cell subsets and numbers of monocytes were not significantly different in the patients compared with the controls. However, the number and proportion of CD4+CD25+ cells were reduced in acute GBS (mean number 61.7 cells/microl, 95% CI 42.9-80.4 and mean percentage 4.6%, 95% CI 3.8-5.4) compared with controls (mean number 99.8 cells/microl, 95% CI 74.7-124.9, p=0.02, and mean percentage 6.0%, 95% CI 4.9-7.1%, p=0.037). In addition, in GBS patients, the number and proportion of CD4+ T cells expressing CD25+ and HLA-DP, DQ, DR (mean number 11.9 cells/microl, 95% CI 7.6-16.1 and mean percentage 0.8%, 95% CI 0.5-1.1%) was lower than in healthy controls (23.5 cells/microl, 95% CI 16.4-30.6, p=0.01, and mean percentage 1.4%, 95% CI 1.1-1.8%, p=0.005. Since CD4+CD25+ cells include cells with special immunoregulatory functions, further investigation of this phenomenon and its relation to possible loss of regulatory T cell function in GBS is warranted.

[Histopathological features of chronic inflammatory demyelinating polyradiculoneuropathy]

Chronic inflammatory demyelinating polyneuropathy (CIDP) was proposed by Dyck et al. in 1975. Diagnosis was based mainly on nerve biopsy features with segmental demyelination, onion bulb formation and inflammatory infiltrates. In many pathological studies, frequencies of these features of CIDP were not observed in the same percentages. Limitations on the nerve biopsy were explained by the study of small, distal, only sensory nerve specimens in the lower limb. In recent years, the usefulness of nerve biopsy has been reconsidered. If electron microscopy and teased-fiber studies are used, the examination can recognize CIDP erroneously classified as chronic idiopathic axonal polyneuropathy. Therapeutic options should be guided by suggestive abnormalities of demyelination and or inflammation on nerve biopsy even in the presence of a electrophysiologic axonal pattern.

Mechanisms of immune regulation in the peripheral nervous system

The peripheral nervous system (PNS) is a target for heterogenous immune attacks mediated by different components of the systemic immune compartment. T cells, B cells, and macrophages can interact with endogenous, partially immune-competent glial cells and contribute to local inflammation. Cellular and humoral immune functions of Schwann cells have been well characterized in vitro. In addition, the interaction of the humoral and cellular immune system with the cellular and extracellular components in the PNS may determine the extent of tissue inflammation and repair processes such as remyelination and neuronal outgrowth. The animal model experimental autoimmune neuritis (EAN) allows direct monitoring of these immune responses in vivo. In EAN contributions to regulate autoimmunity in the PNS are made by adhesion molecules and by cytokines that orchestrate cellular interactions. The PNS has a significant potential to eliminate T cell inflammation via apoptosis, which is almost lacking in other tissues such as muscle and skin. In vitro experiments suggest different scenarios how specific cellular and humoral elements in the PNS may sensitize autoreactive T cells for apoptosis in vivo. Interestingly several conventional and novel immunotherapeutic approaches like glucocorticosteroids and high-dose antigen therapy induce T cell apoptosis in situ in EAN. A better understanding of immune regulation and its failure in the PNS may help to develop improved, more specific immunotherapies.

Pathogenesis of chronic inflammatory demyelinating polyradiculoneuropathy

The acute lesions of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) consist of endoneurial foci of chemokine and chemokine receptor expression and T cell and macrophage activation. The myelin protein antigens, P2, P0, and PMP22, each induce experimental autoimmune neuritis in rodent models and might be autoantigens in CIDP. The strongest evidence incriminates P0, to which antibodies have been found in 20% of cases. Failure of regulatory T-cell mechanism is thought to underlie persistent or recurrent disease, differentiating CIDP from the acute inflammatory demyelinating polyradiculoneuropathy form of Guillain-Barré syndrome. Corticosteroids, intravenous immunoglobulin and plasma exchange each provide short term benefit but the possible long-term benefits of immunosuppressive drugs have yet to be confirmed in randomised, controlled trials.

Chronic inflammatory demyelinating polyradiculoneuropathy in two children with type 1 diabetes mellitus

An association between chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and type 1 diabetes has been described in adults, but not previously in children. Two adolescents with both CIDP and type 1 diabetes are reported here. In order to raise the awareness of CIDP among pediatricians, a description of the clinical and laboratory features, treatment, and prognosis of the condition is provided. A preliminary study was undertaken to determine whether responses to autoantigens in peri-islet Schwann cells and Schwann cells may account for the association between type 1 diabetes and CIDP. Lymphocyte proliferation in response to these autoantigens was abnormal in one of the two patients, but was also abnormal in one control subject.

Concomitant chronic inflammatory demyelinating polyneuropathy and myasthenia gravis following cytomegalovirus infection

We describe a patient who concomitantly developed chronic inflammatory demyelinating polyneuropathy (CIDP) and myasthenia gravis (MG) following cytomegalovirus (CMV) infection. Whereas CIDP and MG presumably have different immunopathogeneses, a number of reports presented cases with CIDP and MG, some of which were concomitant cases. Several reports described association between CIDP or MG, and CMV infection, although the association is still a matter of controversy. This is the first report of patients with concomitant CIDP and MG following CMV infection. The association may be coincidental, but the possibility that CMV infection triggered development of both CIDP and MG simultaneously cannot be excluded.

Intractable chronic inflammatory demyelinating polyneuropathy treated successfully with ciclosporin

BACKGROUND

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a heterogeneous disorder and both clinical course and response to treatment vary widely. Because of the propensity for relapse, CIDP requires maintenance therapy after the initial response to treatment. There is no consensus regarding this in the published literature.

PRESENT REPORT

A patient with CIDP was treated with oral prednisolone and cyclophosphamide pulse therapy but required repeated plasma exchange and intravenous immunoglobulin (IVIg). Treatment with ciclosporin freed the patient from repeated IVIg administration. Therapeutic responses in 14 subsequent cases including three patients who showed improvement with ciclosporin are also presented along with an algorithm of the authors' suggested protocol for treatment.

CONCLUSION

Ciclosporin should be considered for patients with intractable CIDP who require repeated IVIg.

[The role of the immune system in hereditary demyelinating neuropathies]

Hereditary neuropathies, e.g., Charcot-Marie-Tooth (CMT) disease, are inherited diseases of the peripheral nervous system causing chronic progressive motor and sensory dysfunction. Most neuropathies are due to mutations in myelin genes such as PMP22, P0, and the gap junction protein Cx32. Myelin mutant mice are regarded as suitable animal models for several forms of hereditary neuropathies and are important neurobiological tools for the evaluation of pathogenetic and therapeutic concepts in hereditary neuropathies. Using these animal models we could recently show that the immune system is involved in the pathogenesis of hereditary neuropathies. Due to the phenotypic similarities we also consider the immune system important for human inherited neuropathies, in particular since several case reports demonstrate a beneficial effect of immune therapies in patients with hereditary neuropathies. In this review we compare findings from animal models and human disease to elucidate the role of the immune system in hereditary neuropathies.

Inflammatory neuropathies

We discuss two of the most common of the acquired inflammatory neuropathies: Guillain-Barre syndrome and chronic inflammatory demyelinating polyneuropathy, as well as their variants. We review their clinical presentation, electrophysiologic findings, and management, highlighting knowledge gained from the recent literature. Unfortunately, although treatments exist for both Guillain-Barre syndrome and chronic inflammatory demyelinating polyneuropathy, none are completely curative and all have significant potential side effects and/or expense. Better understanding of the underlying pathophysiology of these diseases is needed in order to develop more targeted therapies.

A review of the medical management of chronic inflammatory demyelinating polyradiculoneuropathy

Chronic idiopathic demyelinating polyradiculoneuropathy (CIDP) is a rare condition, but merits consideration due to its disabling consequences for patients and the growing existence of efficacious therapies during the last few decades. The first step is to characterise this neuropathy among the chronic dysimmune polyneuropathies, according to clinical, electrophysiologicalal and sometimes pathologicalal and immunochemical criteria. Typical CIDP is currently defined by criteria which have progressively improved since the first attempt made by an Ad Hoc Subcommittee of the American Academy of Neurology in 1991. However, CIDP may be associated with several concurrent diseases, and other chronic demyelinating polyneuropathies may be considered as either subtypes of CIDP, such as sensory CIDP and multifocal acquired sensory and motor neuropathy, or frontiers of CIDP, such as multi-focal motor neuropathy and polyneuropathy associated with monoclonal gammopathy. These considerations are helpful in the choice of treatments, as the response to immunomodulatory agents is different according to the type of the dysimmune neuropathy. CIDP is considered to be an immune-mediated disorder and may respond dramatically to numerous short-term therapies, such as corticosteroids, plasma exchanges, or intravenous immunoglobulin. The aim of this review is both to summarise the main results of the published open and randomised controlled trials for CIDP, and to provide some information about randomised controlled trials currently in progress. The objectives of the current and future trials are firstly, to choose the best regimen for short-term treatments, and secondly, to test new immunosuppressants in long-term therapy, if the neurological condition requires it.

Clinical manifestations of chronic inflammatory demyelinating polyneuropathy with anti-cardiolipin antibodies

OBJECTIVE

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune syndrome where certain autoantibodies define clinicopathologic subgroups. In the present study, serum anti-cardiolipin antibodies (aCL) were evaluated.

MATERIALS AND METHODS

We investigated aCL in sera from 21 patients diagnosed with CIDP in our hospital between 1991 and 2001. The four CIDP patients with aCL (aCL+) were compared with 17 patients without aCL (aCL-).

RESULTS

All aCL+ patients displayed sensory-motor polyneuropathy, with severity and distribution of weakness resembling those in aCL- patients. Anti-nuclear antibody titer of aCL+ patients were significantly higher than those in aCL- patients. None of aCL+ patients presented clinical manifestations of primary anti-phospholipid syndrome (APS), such as thromboses or recurrent abortion. Although the aCL+ patients were older and had more complications and more severe pathologic features than aCL- patients, they responded well to steroid pulse or intravenous immunoglobulin.

CONCLUSION

The aCL in CIDP apparently differ from 'autoimmune' aCL in APS, instead being among the autoantibodies pathologically involved in CIDP subgroups.

CCR5 deficiency does not prevent P0 peptide 180–199 immunized mice from experimental autoimmune neuritis

Experimental autoimmune neuritis (EAN) is an inflammatory autoimmune demyelinating disease of peripheral nervous system (PNS) and represents an animal model of Guillain-Barré syndrome (GBS) in man. The inflammatory cell infiltrating into the PNS is a prerequisite for developing EAN. To explore the role of CC chemokine receptor 5 (CCR5) in the inflammatory process of EAN, we induced EAN in CCR5-deficient (CCR5(-/-)) mice with P0 protein peptide 180-199. We found that CCR5(-/-) mice showed a similar EAN clinical course and severity as well as profile of infiltrating macrophages and T cells in cauda equina (CE) of EAN and the same levels of spleen mononuclear cell (MNC) response to antigen and mitogen when compared with CCR5(+/+) control mice. However, increased IP-10 and MIP-1beta production in sciatic nerves were seen in CCR5(-/-) mice. These results suggest that CCR5 deficiency does not prevent P0 peptide 180-199-immunized mice from EAN. Increased MIP-1beta and IP-10 in sciatic nerves may compensate the CCR5 deficiency and contribute to inflammatory cells infiltrating to the PNS.

Immune-mediated components of hereditary demyelinating neuropathies: lessons from animal models and patients

Most demyelinating forms of Charcot-Marie-Tooth type 1 (CMT1) neuropathy are slowly progressive and do not respond to anti-inflammatory treatment. In nerve biopsy samples, overt lymphocytic infiltration is absent, but pathological features typical of macrophage-related demyelination have been reported. In mouse models of CMT1, demyelination was substantially reduced when the mutants were backcrossed into an immunodeficient genetic background. A few individual patients with CMT1 respond to anti-inflammatory treatment; however, unlike most patients with CMT1, these patients show accelerated worsening of symptoms, inflammatory infiltrates in nerve biopsies, and clinical features resembling chronic inflammatory demyelinating polyneuropathy as well as CMT1. We conclude that in patients with typical CMT1 and in animal models, a cryptic and mild inflammatory process not responsive to standard anti-inflammatory treatment fosters genetically mediated demyelination.

Serum tumour necrosis factor-alpha and soluble tumour necrosis factor receptors levels in patients with Guillain-Barre syndrome

OBJECTIVES

To estimate the serum concentrations of Tumour Necrosis Factor alpha (TNF-alpha) and soluble TNF receptors (s TNF-RI and TNF-RII) in patients with Guillain-Barre syndrome (GBS), before and after treatment.

MATERIAL AND METHODS

The serum TNF-alpha and the soluble TNF receptors concentrations were measured by a sandwich enzyme-linked immunosorbent assay (ELISA) in 47 patients with GBS before and after the treatment - IVI therapy (n=26); Plasma Exchange (n=21).

RESULTS

At the time of admission, the serum TNF-alpha concentrations were elevated (32.5-182.5 pg/ml) in 41/47 GBS patients (87.2%). Following the treatment (IVIG or PE), there was a significant decrease in the serum TNF-alpha concentrations (8.5-58.5 pg/ml) in these 41 GBS patients. The soluble TNF receptors, particularly sTNF-RII concentrations were significantly increased in GBS patients treated by IVIG therapy.

CONCLUSIONS

The results of this indicated that (a) Elevated serum concentrations of TNF-alpha showed a positive correlation with the disease severity in patients with GBS. (b) The decrease in the serum TNF-alpha and increase in the serum soluble TNF receptors, particularly sTNF-RII showed a positive correlation with the neurological recovery in GBB patients following treatment.

Aberrated levels of cerebrospinal fluid chemokines in Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy

Infiltration of spinal nerve roots and peripheral nerves by macrophages and T cells are rather consistent immunopathologic findings in patients with Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Chemokines play a central role in recruitment of leukocytes to inflamed tissue. Chemokines have been implicated in the pathogenesis of the experimental autoimmune neuritis (EAN), which represents an animal model of GBS, but the role of chemokines in GBS and CIDP is not clear. Since chemokines may be released into CSF from inflamed spinal nerve roots, we studied the concentrations of the chemokines MCP-1, MIP-1beta, MIP-3beta, IP-10, SDF-1alpha, RANTES, and SLC in the CSF by sandwich ELISA in patients over the course of GBS and CIDP, before and after immunomodulatory treatment. Controls consisted of patients with noninflammatory neurological disorders. Patients examined in the acute phase of GBS prior to treatment with intravenous high dose immunoglobulins (IvIg) had elevated CSF levels of MCP-1 (a chemoattractant for blood monocytes and dendritic cells) and IP-10 (a chemoattractant for T cells). Patients with CIDP examined prior to immunomodulatory treatment had elevated CSF levels of MIP-3beta (a chemoattractant for mature dendritic cells, naïve and recently activated T cells) and IP-10. Levels of MIP-3beta tended to decreased during follow-up in those CIDP patients responding favorably to immunomodulatory treatment. CSF levels of MCP-1 and IP-10 correlated with the CSF:plasma albumin ratio in both GBS and CIDP patients. In CIDP patients, CSF levels of MIP-3beta also correlated with the CSF:plasma albumin ratio. These data implicate MCP-1 and IP-10 in the pathogenesis of GBS, and IP-10 and MIP-3beta in the pathogenesis of CIDP.

Cytokines in sural nerve biopsies from inflammatory and non-inflammatory neuropathies

Proinflammatory cytokines are supposed to play a major role in the pathophysiology of vasculitis and in the development of neuropathic pain. Here we studied the cytokine expression in sural nerve biopsy specimens from patients with vasculitic and other inflammatory and non-inflammatory neuropathies, and investigated whether an increased cytokine expression was correlated with the presence of neuropathic pain. We used immunohistochemistry including double labeling and morphometry to localize and quantify the expression of interleukin-1 beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF) in sural nerve biopsy samples of 41 patients with vasculitic neuropathy (VANP), chronic inflammatory demyelinating neuropathy (CIDP), non-inflammatory chronic axonal neuropathy (CANP), and 3 controls. Overall cytokine immunoreactivity was highest in VANP, less strong in CIDP and lowest in CANP. Cytokine immunoreactivity was directly correlated with the degree of axonal degeneration, endoneurial macrophages and epineurial T cells. In VANP and CANP, a higher cytokine content was associated with neuropathic pain.

Anti-GM1 IgG antibodies induce leukocyte effector functions via Fcgamma receptors

Guillain-Barré syndrome (GBS) is an immune-mediated neuropathy, in which leukocytes and humoral components of the immune system proposedly initiate localized inflammation. An important pathogenic role for anti-GM1 ganglioside antibodies has been suggested. Therefore, we evaluated anti-GM1 IgG antibody-induced leukocyte effector functions such as degranulation and phagocytosis using serum of 24 GBS patients. Serum without anti-GM1 antibodies of 9 GBS patients as well as pooled serum from healthy individuals served as controls. Ten out of 15 (67%) of anti-GM1 IgG positive sera were capable of inducing leukocyte degranulation, and 8 out of 15 (53%) of anti-GM1 IgG positive sera were capable of inducing phagocytosis of GM1-coated beads. In all of these sera anti-GM1 antibody titers were >or=1:800. No leukocyte degranulation or phagocytosis was observed in control sera. Leukocyte activation was completely abrogated in the presence of IgG receptor (FcgammaR) blocking antibodies, suggesting a crucial role for leukocyte FcgammaR in GBS pathogenesis. No correlation of antibody titers with the extent of leukocyte activation, or severity of disease was observed. These data document the capacity of anti-GM1 IgG antibodies to activate leukocyte inflammatory functions, and suggest an important role for anti-ganglioside IgG antibodies in the pathogenesis of GBS.

Management of chronic inflammatory demyelinating polyradiculoneuropathy

This review briefly describes current concepts concerning the nosological status, pathogenesis and management of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). CIDP is an uncommon variable disorder of unknown but probably autoimmune aetiology. The commonest form of CIDP causes more or less symmetrical progressive or relapsing weakness affecting proximal and distal muscles. Against this background the review describes the short-term responses to corticosteroids, intravenous immunoglobulin (IVIg) and plasma exchange that have been confirmed in randomised trials. In the absence of better evidence about long-term efficacy, corticosteroids or IVIg are usually favoured because of convenience. Benefit following introduction of azathioprine, cyclophosphamide, cyclosporin, other immunosuppressive agents, and interferon-beta and -alpha has been reported but randomised trials are needed to confirm these benefits. In patients with pure motor CIDP and multifocal motor neuropathy, corticosteroids may cause worsening and IVIg is more likely to be effective. General measures to rehabilitate patients and manage symptoms, including foot drop, weak hands, fatigue and pain, are important.

Changes in serum macrophage-related factors in patients with chronic inflammatory demyelinating polyneuropathy caused by intravenous immunoglobulin therapy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a slowly progressive or recurrent neuropathy accompanied by infiltration of macrophages in the peripheral nerves. Macrophage colony-stimulating factor (M-CSF) and monocyte chemoattractant protein-1 (MCP-1) are a macrophage-related cytokine and chemokine, respectively. Although, intravenous immunoglobulin (IVIg) infusion therapy has been used for treating CIDP patients, not all CIDP patients have responded to IVIg infusion therapy. To determine the mechanisms of the action of IVIg, we examined serum M-CSF and MCP-1 levels during and after IVIg infusion therapy in 19 CIDP patients treated with IVIg (0.4 g/kg/day for 5 days). Ten of the 19 patients (52.6%) responded to IVIg therapy. Both M-CSF and MCP-1 concentrations in IVIg responders were significantly higher on day 1 postinfusion than those in nonresponders, but decreased to their pretreatment values on day 5 postinfusion. The results suggest that immunomodulation through M-CSF and MCP-1 is involved in the mechanisms underlying the effect of IVIg infusion therapy in CIDP patients.

Peripheral neuropathy in systemic lupus erythematosus: pathomorphological features and distribution pattern of matrix metalloproteinases

Matrix metalloproteinases (MMPs) are endoproteases that have been implicated in the pathogenesis of inflammatory and vasculitic neuropathies. In systemic lupus erythematosus (SLE), a peripheral neuropathy is frequently seen that is thought to be caused by ischemic nerve damage due to vasculopathy and/or vasculitis of the nutritional vessels. However, the exact pathomechanisms causing SLE neuropathy are largely unknown. Elevated MMP levels have been reported in the serum of SLE patients. Supposing that altered expression of MMPs may contribute to vessel wall damage in SLE neuropathy, we investigated the expression of MMP-1, -2, -3, -9, -10 and -13, and their tissue inhibitors (TIMP-1 and -2) in sural nerves from 12 SLE patients in comparison to normal controls. All MMPs could be detected within blood vessel walls from SLE nerves, whereas in controls MMP-3 and MMP-9 was not found. TIMP-1 and TIMP-2, on the other hand, were not informative. Generally, small and large nutritional vessels in the epineurium were immunoreactive for MMPs and TIMPs. Mononuclear cells, which expressed MMP-1, - 3, -10, -13, and TIMP-1 were also observed in most of the SLE nerves, mostly around epineurial blood vessels, but only occasionally in controls. This indicates that expression of MMPs in mononuclear cells may be related to leukocyte trafficking through the vessel walls. However, the density of TIMP-positive and MMP-positive inflammatory cells did not correlate with morphometric parameters regarding the severity of the neuropathy. Our findings suggest that especially the up-regulation of MMP-3 and MMP-9 within the vessel walls may be responsible for the vascular damage seen in SLE and the resulting chronic combined axonal and demyelinating type of neuropathy frequently found in SLE.

Severe chronic sensory-motor polyneuropathy: coexistence of 3 unrelated etiologies in a type 1 diabetic patient. A case report and review of the literature

We present the case of a 58-year-old man, who has suffered from type 1 diabetes mellitus since he was young. He had monoclonal IgM kappa gammopathy of undetermined significance and high anti-MAG antibody titer. He developed a polyneuropathic picture with the clinical and laboratory features of chronic inflammatory demyelinating polyneuropathy within the span of approximately 2 years. He benefited from IV administration of high doses of immunoglobulins. Investigation of all parameters, but particularly of the clinical phenotype, can lead to a better definition of the polyneuropathic picture, especially for therapeutic and prognostic purposes.

Pathological findings in a patient with ventilatory failure and chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) may cause significant disability, but severe respiratory complications are uncommon. We describe the case of a 49-year-old man with clinical features of CIDP for 5 years who died of respiratory failure. Post-mortem findings of denervation in diaphragm muscle and axonal loss in phrenic nerve are presented. Severe ventilatory failure may occur in CIDP when neuropathy affects the respiratory muscles. Attention to early clinical features of respiratory insufficiency may facilitate the prevention of more severe features of respiratory failure.

Animal models of immune-mediated neuropathies

PURPOSE OF REVIEW

This article gives an overview on animal models for immune-mediated demyelinating disorders of the peripheral nervous system. As insight into human disease is mainly based on biopsy material and ex-vivo analysis, an understanding of the pathogenetic mechanism of these complex and heterogeneous disorders is mainly based on animal models.

RECENT FINDINGS

Besides experimental autoimmune neuritis in rats, recent efforts to establish this model in mice are discussed. In addition, models for spontaneous autoimmune neuropathies and secondary immune reactions in degenerative disorders of the peripheral nervous system are reviewed.

SUMMARY

Recently described animal models offer the possibility to analyse the complex interaction of genetic and immunological factors. The entire panel of animal models for immune-mediated disorders of the peripheral nervous system provides a rational basis for studying the mechanisms of pathogenesis and new immunotherapeutic strategies for human autoimmune demyelinating neuropathies.

Immune mechanisms in acquired demyelinating neuropathies: lessons from animal models

The peripheral nervous system (PNS) is the target for a heterogenous immune attack mediated by T-cells, B-cells, and macrophages. The interaction of the humoral and cellular immune system with the structural components in the peripheral nervous system may determine the extent of inflammation and possibly repair mechanisms. The animal model experimental autoimmune neuritis (EAN) allows detailed study of the various effector pathways and tests novel therapeutic strategies in vivo. Unexpectedly, involvement of the immune system is also found in animal models for inherited neuropathies and in its human counterpart Charcot-Marie-Tooth (CMT) disease, suggesting an autoimmune reaction triggered by the genetically determined demyelinating disorder. A better understanding of immune regulation and its failure in the peripheral nervous system may help to develop more specific and more effective immunotherapies.

Chemokines and chemokine receptors in inflammatory demyelinating neuropathies: a central role for IP-10

Inflammatory cell recruitment is an important step in the pathogenesis of autoimmune demyelinating diseases of the PNS. Chemokines might play a critical role in promoting leucocyte entry into the nervous system during immune-mediated inflammation. Here, we report the expression pattern of the chemokine receptors CCR-1, CCR-2, CCR-4, CCR-5 and CXCR-3 in sural nerve biopsies obtained from patients with classical Guillain-Barré syndrome (acute inflammatory demyelinating polyradiculoneuropathy), chronic inflammatory demyelinating polyradiculoneuropathy and various non-inflammatory neuropathies. A consistent chemokine receptor expression pattern was immunohistochemically detected in inflammatory demyelinating neuropathies and quantitation of labelled mononuclear cells revealed significantly elevated cell counts compared with controls. CCR-1 and CCR-5 were primarily expressed by endoneurial macrophages, whereas CCR-2, CCR-4 and CXCR-3 could be localized to invading T lymphocytes. Quantitative analysis revealed that CXCR-3 was expressed at highest numbers by infiltrating T cells compared with the other receptors. Thus, expression and distribution of CXCR-3 suggest a specific role of this receptor in chemokine-mediated lymphocyte traffic into the inflamed PNS tissue. Therefore, we further analysed the expression of its ligands interferon-gamma-inducible protein of 10 kDa (IP-10) and monokine induced by interferon-gamma (Mig). Significantly increased levels of IP-10 could be measured in the CSF of patients with inflammatory neuropathies, whereas no differences were observable for Mig. In situ hybridization for IP-10 mRNA mirrored the distribution of the cognate receptor within the inflamed PNS, and delineated endothelial cells as the primary cellular source of IP-10. Our results imply a pathogenic role for specific chemokine receptors and IP-10 in the genesis of inflammatory demyelinating neuropathies.