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In most dysimmune neuropathies, historically the microscopical lesions were described prior to immunological studies. The latter along with neuropathological studies have found some immune, albeit incomplete, explanations of the mechanisms of these lesions which we will describe in two main syndromes: the primitive auto-immune inflammatory peripheral polyneuropathies (GBS and CIDP) and polyneuropathies induced by a monoclonal dysglobulinemia. In some patients who have to be discussed case by case pathology (nerve biopsy) will confirm the diagnosis, may help to delineate the molecular anomalies and identify lesional mechanisms. We will review the high variability of nerve lesions which is characteristic of dysimmune neuropathies. Pathological studies confirm that both humoral and cellular immune reactions against Schwann cell and/or axonal antigens are implicated in primitive dysimmune neuropathies due to a dysfunction or failure of immune tolerance mechanisms. In case of a polyneuropathy associated to a monoclonal dysglobulinemia, pathological and immunological studies have shown that in many patients, the dysglobulinemia did harm the peripheral nerve; knowledge of the pathological lesions and their mechanisms is of major interest for orienting specific treatments., (Copyright © 2014. Published by Elsevier Masson SAS.)

Introduction: Peripheral neuropathies sometimes complicate bariatric surgery., Patients and Methods: We report the detailed clinical, electrophysiological, biological and histological characteristics of five patients who developed peripheral neuropathy after bariatric surgery., Results: Three patients presented with small fiber neuropathy, one presented with axonal polyneuropathy, and one with demyelinating polyradiculoneuropathy. All patients had in common prominent neuropathic pain, massive weight loss, and multiple nutritional deficiencies. The pathophysiology of postbariatric surgery polyneuropathies is complex and involves nutritional, infectious and dysimmune mechanisms., Conclusion: The spectrum of peripheral neuropathies complicating bariatric surgery is wide, and includes pure small fiber neuropathy, axonal polyneuropathy, and demyelinating polyradiculoneuropathy. Treatment is mainly preventive, but sometimes surgical revision is needed., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Introduction: Neurological manifestations of systemic lupus erythematosus are frequent and polymorphic. In 40% of cases, lupus can be revealed by neurological symptoms. Cerebral nervous system complications predominate and can be a negative factor for prognosis. Peripheral features are rare and various and can compromise functional prognosis, sometimes with fatal outcome., Case Report: We report the case of a 30-year-old woman who presented a cerebral venous thrombosis of the superior longitudinal sinus. Outcome was favorable with antibiotics and anticoagulants. Four months later, she developed an acute polyradiculoneuritis associated with an inflammatory syndrome and positive tests for antinuclear antibody and antinuclear anti-DNA. The diagnosis of neurolupus was retained on the basis of four criteria of the American college of Rheumatology. The patient was given steroid therapy associated with a course of intravenous immunoglobulin. She has fully recovered her deficit., Conclusion: Cerebral venous thrombosis and acute polyradiculonévrites are rare events in systemic lupus erythematosus. Early diagnosis and management are crucial., (2009 Elsevier Masson SAS. All rights reserved.)

Introduction: Several extra-intestinal manifestations of inflammatory bowel disease have been reported, although reports of neurologic disorders are rare., Case Reports: We report two cases of peripheral and central neurological manifestations of inflammatory bowel disease. The first case is a 33-year-old woman who developed acute inflammatory demyelinating motor polyneuropathy in association with Crohn's disease. Her symptoms improved with immunomodulatory therapies. Our second case is a 46-year-old woman, previously diagnosed with ulcerative colitis that subsequently developed ischemic stroke concomitantly to severe exacerbation of digestive symptoms. Her radial and humeral pulses were unequal bilaterally. Associated Takayashu's arteritis was suspected. The cardiovascular and immunological assessments were negative. Complementary investigations were foreseen but the patient died early of acute abundant rectal bleeding., Conclusion: This paper focuses essentially on the probable manifestations of inflammatory bowel disease in the nervous system, particularly peripheral neuropathies and stroke. We discuss different pathophysiologic mechanisms incriminated, notably thromboembolism and immunological abnormalities.

Introduction: Tumor necrosis factor- (TNF) blockers are efficient in the treatment of autoimmune disorders such as inflammatory bowel disease and rheumatoid arthritis, but can induce CNS adverse effects including retrobulbar optic neuritis or aggravation of multiple sclerosis., Observation: We report a case of progressive demyelinating polyneuropathy after initiation of Adalimumab (Humira). Corticosteroid and intravenous immunoglobulins were ineffective but the neuropathy improved within six months after adalimunab discontinuation., Discussion: This case, and other reports recently published suggest that anti-TNF alpha drugs can induce demyelinating neuropathy., Conclusion: Clinicians should be on the lookout for signs evocating neuropathy in patients given anti TNF alpha.

Chronic inflammatory demyelinating polyradiculoneuropathy is an autoimmune disease that target myelin sheats of peripheral nerves. Its diagnosis is often difficult to make, and a number of cases are probably not identified because of the clinical and electrophysiological heterogeneity. Typical cases associate progressive or relapsing-remitting motor and sensory deficit with increased CSF protein content and electrophysiological features of demyelination. In some cases electrophysiological studies fail to show evidence of demyelination, conventional electrophysiological diagnostic criteria are not filled yet the patient may respond to immunomodulatory treatments. In such cases, presence of clinical characteristics suggestive of CIDP (that means not compatible with a length-dependent axonal process) are critical justifying fully investigations including sural nerve biopsy. The main clinical characteristic are: a symmetric proximal and distal motor weakness predominantly affecting the lower limbs, a diffuse areflexia, a sensory deficit characterized by a preferential involvement of large fibers, an evolution which may be either chronic progressive or recurrent. Usual therapeutic agents (corticosteroids, intravenous immunoglobulins, plasma exchanges) seem to have the same efficacy whatever the electrophysiologic profile.

Introduction: The consequences of axonal or demyelinating injuries on the axonal cytoskeleton have rarely been described., Methods: We have compared the density of fibers labeled by anti-neurofilaments (NF) and -beta tubulin (TUB) to the density of total fibers in nine patients with axonal neuropathies of undetermined etiology (AUE), six with necrotizing angeitis with neuropathy (NAN), seven with chronic inflammatory demyelinating neuropathy (CIDP) and in five controls, as well as in six patients with chronic multiple sclerosis (MS). We also studied demyelinated rat corpus callosum after lysophosphatidyl (LPC) microinjection., Results: In AUE and NAN NF positive fibers decreased together with total fiber density, whereas TUB increased. In demyelinating lesions TUB was not altered (CIDP) or strongly decreased (MS, LPC); NF were strongly reduced in MS (where axon loss was prominent) and in LPC lesions (despite the lack of fiber degeneration) and for fiber densities<3900/mm2 in CIDP., Conclusion: The initial mechanism of a disease, either axonal degeneration or demyelination, could result into a specific pattern of axonal cytoskeleton alterations.

A 33-year-old man presented an acute motor demyelinating neuropathy following Campylobacter jejuni enteritis. The patient was improved with an IgIV treatment. Clinical features and course time were compatible with the diagnosis of a Guillain-Barré syndrome. The electrophysiologic studies were in favor of multifocal motor neuropathy with conduction blocks. We discuss the nosologic group of this neuropathy.

Acute demyelinization of the peripheral nervous system is a characteristic feature of Guillain-Barré syndrome. Lesions of the spinal roots predominate with more or less diffuse multifocal peripheral demyelinization. Inflammatory lesions of the distal peripheral nervous system are less common. Segmentary demyelinization of nerve fibers accompanying inflammatory lesions show characteristic penetration of macrophages within a normal appearing myelin sheath. The myelin on the segments concerned is rapidly destroyed by phagocytosis and removed with the macrophages. Once the debris has been removed, the axons are remyelinized after proliferation of the Schwann cells. In monophasic cases, the entire processes occurs over a 2-3 week period allowing remyelinization and rapid functional recovery. In prolonged cases, flare-ups of demyelinization, non remyelinization or damage to the axons can retard recovery. The mechanism and impact of axon damage which accompanies demyelinization at various degrees and which may predominate in certain cases, is discussed here.

Idiopathic chronic inflammatory polyradiculoneuropathies are probably due to dysimmune mechanisms. They form a distinct entity defined by clinical, electrophysiological, histopathological criteria and by their evolution and response to treatment. The homogeneity of that syndrome, the exact nature of the underlying pathological processus, the natural history and the responses to treatment are still debated. Need to more studies, especially of immunologic nature, to precise limits and criteria of such a syndrome. Chronic polyradiculoneuropathy is different from acute form mainly by evolution. Within the chronic form, the progressive and relapsing forms can be distinguished with different electrophysiologic characteristics. These 2 forms share the same electrophysiologic aspect of chronic demyelination which is characterized by slowing of nerve conduction, conduction block and temporal dispersion. They had some specific different features such as the heterogeneity of the conduction failure and the multifocal distribution of demyelinating lesions. The histopathologic lesions are those of demyelination-remyelination with some degree of axonal damage, although inflammatory infiltrates are not frequent. In the majority of cases, the motor deficit is dominant although pure sensory forms have been reported. In few cases, central nervous system involvement is described. Idiopathic polyradiculoneuropathies had different electrophysiologic features than polyneuropathies associated with IgM monoclonal gammopathy and anti-MAG activity, these later presenting more distal and homogeneous abnormalities.

Cytomegalovirus (CMV) infection of the nervous system is frequent in acquired immunodeficiency syndrome (AIDS) and can be responsible for encephalitis, encephalomyelitis, meningoradiculitis or polyradiculo-neuropathy. Encephalitis is characterized at microscopy by its periventricular and cerebellar location, and by the presence of cytomegalic cells, containing intranuclear and/or intracytoplasmic inclusions, microglial nodules and necrotic foci. The virus can infect almost all types of cells. Coexistence of CMV and HIV has been observed in giant cells of macrophagic origin. It has been suggested that the two viruses could act in synergy. The nervous system is seldom infected by the varicella-zoster virus (VZV) in AIDS. The infection can be responsible for multifocal leukoencephalitis, ventriculitis, vascular lesions associated or not with cerebral infarction, or with meningomyeloradiculitis. In almost all cell types Cowdry's type A intranuclear inclusions have been found. The virus can be demonstrated by immunohistochemistry or in situ hybridization. VZV antigens have been reported in the walls of vessels damaged by a non inflammatory obliterating vasculopathy or by a granulomatous angiitis. Coexistence of VZV and HIV has been observed in giant cells of macrophagic origin, and synergy between those two viruses has been suspected.

Four patients with acute inflammatory polyradiculoneuropathy were evaluated with MRI. In 3 of 4 cases, gadolinium enhancement was observed in the nerve roots of cauda equina, on frontal and horizontal slices. This enhancement was correlated with the severity of the clinical picture and the cerebrospinal-fluid inflammatory protein concentration and supports the inflammatory nature of this forms of acute polyradiculoneuropathy.

Serum from 3 of 4 patients with classical Guillain-Barré syndrome has produced conduction block in a large proportion of motor axons following subperineurial injection into 13 rat sciatic nerves. These effects, although qualitatively similar to those previously described for certain experimental sera (EAN, EAE, and anti-Gal-Cer), are notably slower in evolution. Conduction block does not begin until more than 24 hours after injection and is maximal at about 5 days. Between 6 and 8 days the appearance of long latency responses signals return of conduction in previously blocked axons. Thereafter return to control values is rapid and complete within 10 to 15 days. Six control human sera injected into 13 sciatic nerves have shown no comparable effect. Correlative morphological studies indicate that these Guillain-Barré sera produce focal demyelination which evolves pari passu with conduction block. Demyelination appears to evolve both by vesicular disruption and by macrophage mediated myelin stripping. A factor is present in the serum of some patients with Guillain-Barré syndrome, which given access to the endoneurial environment produces active demyelination with conduction block. We believe that the production of this factor could be responsible for the polyradiculoneuropathy of this disease.

A 62 year old man developed a neuropathy after several months of treatment with amiodarone. The clinical picture was atypical in that it associated a polyradiculoneuritis with cell-protein dissociation and an axial and peripheral cerebellar syndrome. Pathology of muscle and nerve showed dense inclusions in Schwann cell cytoplasm and in pericytes, highly suggestive of fat inclusions. Discontinuation of amiodarone therapy resulted in a slow regression of disorders. Diabetes mellitus developed. Several pathogenic hypotheses are proposed.

A patient developed polyneuropathy during carbimazole treatment for thyrotoxicosis. Electrophysiological data and a neuromuscular biopsy suggested a combined axonal and demyelinative lesion together with microvasculitis. Physiopathological hypotheses are discussed.

Two further cases of human neurolymphomatosis are reported, and clinical, histopathologic and nosologic features of the affection reviewed with respect to findings in these 2 patients and in 7 other reported cases. Clinical manifestations are those of a flaccid ascending paralysis, associated in most cases with an asymmetrical abolition of tendon reflexes, violent muscular pains and sphincter disturbances, frequently preceded by a regressive cranial nerve palsy. Pathology shows infiltration of the peripheral nervous system (nerves, roots, and spinal ganglia) by lymphoid cells, sometimes associated with central nervous system (cord and brain) infiltrates in severe advanced cases. Involved nerves are increased in size. The disease could be a viral polyradiculoneuritis due to the virus of Marek's disease. Arguments in favor of this hypothesis include: the onset of the affection in subjects working in poultry farms under poor hygienic condition; the fact that clinical and histologic findings are similar to those in Marek's disease and the failure, after careful examination, to detect any malignant blood disorder or lymphoma in one of the cases studied.