Chronic relapsing polyneuritis

Morphological findings on peripheral nerve biopsies in 15 patients with human immunodeficiency virus infection

A peripheral nerve biopsy was performed in 15 patients with human immunodeficiency virus (HIV) infection and polyneuropathy. Two cases [1 asymptomatic, 1 AIDS-related complex (ARC)] presented with chronic inflammatory demyelinating polyneuropathy; there was 1 case (asymptomatic) of mononeuropathy multiplex and 12 cases (1 asymptomatic, 1 ARC, 10 AIDS) with distal symmetrical polyneuropathy. Epi- or endoneurial microvasculitis was observed in 6 cases. Electron microscopy showed that nerve fiber lesions were mainly axonal. Severe segmental demyelination was also present in both cases of chronic inflammatory demyelinating polyneuropathy, with characteristic features of active demyelination in one. Numerous plasmacytoid cells were found in the endoneurium in 4 patients. Tubuloreticular inclusions were present in endothelial cells in the 10 cases with AIDS but absent in the other patients. Direct immunopathological examination with anti-immunoglobulin sera was negative in all cases. HIV was evidenced by in situ hybridization in 2 AIDS patients; no Epstein-Barr virus or cytomegalovirus was detected.

Neuropathological findings in chronic relapsing experimental allergic neuritis induced in the Lewis rat by inoculation with intradural root myelin and treatment with low dose cyclosporin A

Experimental allergic neuritis (EAN) was induced in Lewis rats by inoculation with bovine intradural root myelin and adjuvants. Rats treated with subcutaneous cyclosporin A (CsA) (4 mg/kg on 3 days per week from the day of inoculation until day 29) developed a chronic relapsing course. Tissues from the spinal cord, nerve roots, dorsal root ganglia and sciatic nerve of CsA-treated rats sampled during relapses and remissions were studied by light and electron microscopy. Control rats that were not treated with CsA were studied during or after episodes of acute EAN. Both control and CsA-treated animals studied in the first episode of EAN had evidence of inflammation and primary demyelination of the nerve roots and dorsal root ganglia. In control and CsA-treated animals that had recovered from the first episode there was evidence of remyelination. In CsA-treated animals in the second episode there was severe inflammation and demyelination and remyelination of the nerve roots and dorsal root ganglia, and in addition there was significant demyelination and remyelination in the spinal nerves and sciatic nerves and dorsal columns of the spinal cord, particularly in later stages of disease. In later episodes there was less inflammation, but there was continuing demyelination and onion bulbs were present. In animals sampled after recovery from chronic relapsing EAN onion bulbs were present. Occasional small onion bulbs were also observed in control animals that were inoculated with higher doses of myelin. Plasma cells were present in the inflammatory lesions of later episodes. Mast cells were also observed at different stages of the disease. We conclude that the CsA form of chronic relapsing EAN has clinical and pathological similarities with the human disease, chronic inflammatory demyelinating polyradiculoneuropathy.

Fiber density in acute and chronic inflammatory demyelinating polyneuropathy

The fiber density in the deltoid, extensor digitorum communis, and first dorsal interosseous muscles was measured using SFEMG in 11 patients with acute and chronic inflammatory demyelinating polyneuropathy. The fiber density was increased in 58% of the muscles studied. The deltoid muscle was the most abnormal of the 3 muscles studied. There was no correlation with the clinical syndrome, with conduction block or slowed motor conduction, or with the distribution of weakness. Changes were noted even in patients studied within 3 weeks of presentation, suggesting that reinnervation begins soon after the onset of the disease.

Plasma exchange in polyneuropathy associated with monoclonal gammopathy of undetermined significance

BACKGROUND

Polyneuropathy associated with monoclonal gammopathy of undetermined significance (MGUS) has been treated with plasma exchange, intravenous immune globulin, and chemotherapy, but the effectiveness of these treatments remains uncertain.

METHODS

We randomly assigned 39 patients with stable or worsening neuropathy and MGUS of the IgG, IgA, or IgM type to receive either plasma exchange twice weekly for three weeks or sham plasma exchange, in a double-blind trial. The patients who initially underwent sham plasma exchange subsequently underwent plasma exchange in an open trial.

RESULTS

In the double-blind trial, the average neuropathy disability score improved by 2 points from base line (from 62.5 to 60.5) in the sham-exchange group and by 12 points (from 58.3 to 46.3) in the plasma-exchange group (P = 0.06). A similar difference was observed in the weakness score, a component of the neuropathy disability score (improvement, 1 and 10 points, respectively; P = 0.07). After treatment the summed compound muscle action potentials of motor nerves were 1.2 mV lower (worse) than at base line in the sham-exchange group and 0.4 mV higher (better) in the plasma-exchange group (P = 0.07). The greater degree of improvement with plasma exchange was equal in magnitude to or greater than the difference between not being able to walk on the heels or toes and being able to perform these activities. Changes in the vibratory detection threshold, summed motor-nerve conduction velocity, and sensory-nerve action potentials did not differ significantly between the treatment groups. In the open trial, in which patients who initially underwent sham exchange were treated with plasma exchange, the neuropathy disability score (P = 0.04), weakness score (P = 0.07), and summed compound muscle action potentials (P = 0.07) improved more with plasma exchange than they had with sham exchange. In both the double-blind and the open trial, those with IgG or IgA gammopathy had a better response to plasma exchange than those with IgM gammopathy.

CONCLUSIONS

Plasma exchange appears to be efficacious in neuropathy associated with MGUS, especially of the IgG or IgA type.

Inflammatory demyelinating lesions in two patients with IgM monoclonal gammopathy and polyneuropathy

We report two patients with polyneuropathy and IgM monoclonal gammopathy in whom peripheral nerve biopsy showed the widening of myelin lamellae which is characteristic of IgM paraproteinaemic neuropathy. Moreover, certain myelinated fibres were invaded by histiocytes overloaded with myelin debris, and in some instances elongated macrophage processes could be seen peeling away the myelin lamellae. The latter ultrastructural features are characteristic of inflammatory demyelinating polyneuropathies in both human and experimental pathology. Such an association has not been reported to date in human pathology, but could explain the prevalence of inflammatory demyelinating lesions in experimental models of IgM paraproteinaemic neuropathy. These two cases seem to bridge the gap between inflammatory demyelinating polyneuropathies and polyneuropathies associated with IgM monoclonal gammopathy.

Comparison of electrodiagnostic criteria for primary demyelination in chronic polyneuropathy

Three sets of electrodiagnostic criteria for establishing primary demyelination in chronic polyneuropathy are evaluated. Sensitivity is assessed in 70 patients with clinically established chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The criteria use different abnormal values, one adjusts for the effects of axonal loss, while another relies only on conduction velocity. However, even when consideration is given to sufficient number of nerves tested, there is no significant difference (P = 0.37) in diagnostic sensitivity among them, with 48% to 64% of CIDP patients fulfilling criteria for primary demyelination. Specificity is assessed by applying the criteria to 47 patients with motor neuron disease and 63 patients with diabetic polyneuropathy. No patients meet any of the criteria. Further analysis shows that as sensitivity increases specificity decreases, because of overlapping distributions of nerve conduction abnormalities in these neuropathic disorders. A sensitivity of approximately 66% is a practical limit for electrodiagnostic criteria in CIDP.

Chronic acquired demyelinating motor neuropathy

A patient with chronic, acquired, demyelinating, pure or predominantly motor asymmetric neuropathy is described. Electrophysiological tests showed multifocal conduction block in motor nerves. The sensory system was intact and the first signs of slight trival involvement appeared after 4 years of disease duration. The antiganglioside antibodies were present in serum and the patient responded to immunosuppressive therapy (azathioprine). Distinction of such cases from motor neuron disease is critical since motor demyelinating neuropathy is treatable in most cases.

[Late recurrence of Miller-Fischer syndrome. Physiopathogenic reflections about a case]

The physiopathology of the syndrome of ophtalmoplegia-ataxia-areflexia-hyperproteinorachia, firstly described by FISHER in 1956, remains a matter of controversy among neurologists. We report a new case of recurrence of a MILLER-FISHER's syndrome. The involvement of peripheral and central structures is discussed according to recent knowledges about the immunopathology of inflammatory polyneuropathies.

Monoclonal immunoglobulin bands in the cerebrospinal fluid

Isoelectric focusing and immunofixation allow the detection of abnormal immunoglobulin bands in the cerebrospinal fluid (CSF). In normal subjects, the immunoglobulins in the CSF are derived from serum. In inflammatory disorders of the nervous system, there may be intrathecal immunoglobulin synthesis usually seen as oligoclonal bands confined to the CSF. Monoclonal immunoglobulin bands in the CSF are not common. We surveyed 1490 CSF samples, and found that a total of nine had a monoclonal immunoglobulin band and that in three this was not present in the serum. Of these three, one patient had chronic inflammatory demyelinating polyneuropathy and the antibody may have been secreted by lymphocytes which had infiltrated the nervous system. The other patients had either lymphoma or lymphomatoid granulomatosis within or adjacent to the nervous system and the monoclonal immunoglobulin was probably secreted by B lymphocytes within those lesions.

AAEM minimonograph #34: polyneuropathy: classification by nerve conduction studies and electromyography

Electrodiagnostic evaluation of patients with suspected polyneuropathy is useful for detecting and documenting peripheral abnormalities, identifying the predominant pathophysiology, and determining the prognosis for certain disorders. The electrodiagnostic classification of polyneuropathy is associated with morphologic correlates and is based upon determining involvement of sensory and motor fibers and distinguishing between predominantly axon loss and demyelinating lesions. Accurate electrodiagnostic classification leads to a more focused and expedient identification of the etiology of polyneuropathy in clinical situations.

Cranial magnetic resonance imaging in chronic demyelinating polyneuropathy

Twenty one patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and five patients with chronic demyelinating polyneuropathy associated with benign monoclonal paraproteinaemia none of whom had signs or symptoms of central nervous system disease, had cranial magnetic resonance imaging (MRI) on a 1.5 Tesla unit. Areas of increased white matter signal intensity were seen in one of 10 patients aged less than 50 years and in five of 16 patients aged more than 50 years. In only two of the patients (8%), neither of whom had paraproteinaemia, did the appearance strongly suggest demyelination. The only clinical variable that predicted MRI changes was age (p less than 0.01).

Unmyelinated fibers in sural nerve biopsies of chronic inflammatory demyelinating polyneuropathy

Seven patients aged 29 to 76 years with various clinical subtypes of chronic inflammatory demyelinating polyneuropathy (CIDP) were investigated. Sural nerve biopsies were performed between 7 months and 19 years after onset of disease. Quantitative electron microscopy revealed involvement of primary unmyelinated fibers (UF) in all cases. When compared with age-matched controls from the literature and two controls of our own, there was an increase of degenerating primary UF in all cases, a definite decrease of density per mm2 or number per nerve after subtraction of regenerates of myelinated and unmyelinated fibers in five cases, an increase of denervated Schwann cell complexes of the unmyelinated type in three cases, and an increased incidence of a high ratio (greater than or equal to 3) of primary UF per Schwann cell complex in five cases. Presumably due to the small number and heterogeneity of cases, the results did not correlate with type and duration of CIDP, but were obviously influenced by the degree of demyelination. The possible causes of UF damage in CIDP are discussed.

Chronic inflammatory demyelinating polyneuropathy in childhood: ultrastructural features of peripheral nerve biopsies in four cases

Peripheral nerve biopsies (PNB) from four children suffering from subacute or chronic inflammatory demyelinating polyneuropathy were studied by electron microscopy. Remyelinating features with onion bulb formations, inflammatory cell infiltrates and active demyelinating lesions were strongly suggestive of the disease. In the first case, a second PNB, performed after 7 months of severe subacute course, showed a striking evolution of the lesions. In the second case and in spite of severe neurological symptoms, the PNB was almost normal, suggesting that inflammatory lesions were mainly located in the proximal parts of the nerve. No signs of active demyelination could be seen in the third case but onion bulb formations and inflammatory cell infiltrates were present. In the fourth case, characteristic lesions of active demyelination were associated with a history of familial polyneuropathy; this association suggests an auto-immune process in certain kindreds with hereditary motor and sensory neuropathy.

Focal neuropathy preceding chronic inflammatory demyelinating polyradiculoneuropathy by several years

We report three patients who exhibited an unusual clinical course of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in which mononeuropathic limb weakness developed 2, 11 and 23 years, respectively, before the development of generalized polyradiculoneuropathy. The eventual diagnosis remained uncertain until other causes of neuropathy were excluded, and the clinical disorder progressed to involve the other limbs. Focal or regional variants of CIDP suggest that the pathologic, and perhaps the immunologic, abnormalities can be localized and selective for prolonged periods of time. Although this clinical variant seems to account for a small number of CIDP cases, its recognition may aid in making an early diagnosis.

Cyclosporin A in the treatment of chronic demyelinating polyradiculoneuropathy

Eight patients with chronic inflammatory demyelinating polyneuropathy, five of whom had an associated paraproteinaemia, were treated with cyclosporin in a pilot, uncontrolled study for periods up to three and a half years after failing to respond adequately to corticosteroid and azathioprine therapy and plasmapheresis. Three patients had an excellent response, two with complete remission. In other cases it was possible to reduce the corticosteroid therapy and frequency of plasmapheresis. There were no serious complications of the treatment.

Quantitative analysis of endoneurial T-cells in human sural nerve biopsies

We used immunocytochemical methods on sural nerve biopsies from 42 patients with peripheral neuropathy to identify mononuclear cells, determine whether lymphocytic infiltration occurs in a variety of neuropathies, and identify the subtypes of lymphocytes. Immunostained cells were present in 76% of nerve biopsies. CD3+ cells (T lymphocytes) were greatest in density (cells/mm2). In patients whose CD4:CD8 T cell ratio was measured also in blood and cerebrospinal fluid, the CD4:CD8 T cell ratio was similar in all three compartments. These findings suggest that T lymphocytes are frequently present in nerves obtained from patients with various types of neuropathies and raise questions about factors that attract T lymphocytes into nerve that may be important in pathogenesis.

Polyneuropathies in paediatrics

Non-acute polyneuropathies (PNPs) encountered in paediatrics are reviewed. Emphasis is placed on three main groups of conditions: the relatively rare but treatable dysimmune PNP (chronic relapsing dysimmune polyneuropathies, CRDP); the more common hereditary motor/sensory neuropathies (HMSN and HSN); and the often missed symptomatic neuropathies of some heredodegenerative and neurometabolic disorders. Diagnostic procedures are discussed. One conclusion drawn is that so far metabolic screening procedures do not give any diagnostic or aetiological information in HMSN or in HSN, nor in heredoataxias or heredoparaplegias. When a specific neurometabolic disease is suspected from the clinical symptomatology, individually structured investigations are necessary.

HLA antigens in chronic inflammatory demyelinating polyneuropathy

HLA typing of 71 patients with chronic inflammatory demyelinating polyneuropathy (CIDP) showed an overall increase in frequencies of HLA-A3, -B7, -DR2 as well as concomitantly decreased frequencies of HLA-44 and DR7. The strongest associations were seen with HLA-DR2, -DR7 and -B44 in CIDP overall, although they did not reach statistical significance.

Autonomic function and unmyelinated fibers in chronic inflammatory demyelinating polyradiculoneuropathy

Because autonomic function may be abnormal in some demyelinating peripheral neuropathies, it has been studied with a number of noninvasive and invasive tests in 14 patients with chronic inflammatory demyelinating polyradiculoneuropathy. There were abnormalities of the 30:15 ratio in 3 patients and an abnormal thermoregulatory sweat test in 5 patients. These findings are indicative of mild parasympathetic and sympathetic dysfunction. Minor pathological changes in unmyelinated fibers were demonstrated on morphometric examination of sural nerves of 10 patients.

Macrophage responses in inflammatory demyelinating neuropathies

Macrophages are prominent participants in inflammatory demyelinating neuropathies. To provide a different means of evaluating macrophage behavior, we used immunostaining of teased nerve fibers and endoneurial blood vessels. We assessed the frequency with which macrophages were seen in inflammatory demyelinating neuropathies, their relationship to normal and demyelinating fibers, and their expression of major histocompatibility Class II markers (Ia antigen). In 6 patients with chronic inflammatory neuropathy and 1 with Guillain-Barré syndrome, we found regularly that macrophages were adherent to teased blood vessels. Cells presumed to be entering the nerve were elongated, often with a polarized appearance suggesting motility, and were Ia-positive. After entry into nerve, the Ia-positive macrophages were adherent to both normal and demyelinating fibers. They often retained their Ia positivity after penetrating into the nerve fiber and removing myelin. Foamy macrophages, judged to be postphagocytic, were Ia-negative. The foamy macrophages found adhering to blood vessels were presumed to be leaving the nerve. This pattern of entry as Ia-positive prephagocytic cells and evolution to Ia-negative foamy macrophages was compared with other experimental and human neuropathies.

The idiopathic polyradiculoneuropathies: a historical guide to an understanding of the clinical syndromes

Recognition of the idiopathic polyradiculoneuropathies began with Graves, Landry and Dumenil who, respectively, suggested, implied and established the peripheral nervous system as a site of disease. Over the ensuing decades other neurologists separated the idiopathic disorders from neuropathies of known cause, poliomyelitis and myelopathies. Guillain, Barré and Strohl described the acute benign syndrome and its cerebrospinal fluid abnormalities. Haymaker & Kernohan solidified the features of the acute disorder as did Dyck et al and Prineas & McLeod for the relapsing and chronic conditions. Currently the idiopathic polyradiculoneuropathies are regarded as autoimmune in nature, clinically generalized with some cases having focal involvement, and of varying severity with only occasional fatalities. Neurologists are divided as to whether the acute and chronic disorders represent 2 different conditions or whether they are 2 forms in the spectrum of a single disorder. This author favors the concept of a single disorder with multifarious manifestations.

Cervicogenic, hemicranial attacks associated with vascular irritation or compression of the cervical nerve root C2. Clinical manifestations and morphological findings

Sixteen patients suffering from hemicranial attacks are reported. After many years of unsuccessful conservative treatment (mean = 12.4 years), the patients were treated surgically with good results. The radiological or electrophysiological examinations were non-specific or negative. Only vasoactive tests (provoking or relieving pain) or local anesthesia proved helpful in diagnosing and localizing the origin of pain. Intraoperatively, hemicranial attacks were found to be caused by vascular irritation or compression of the cervical nerve root C2. After decompression (n = 6) or dissection (n = 10) of the nerve root and the ganglion, 12 patients were relieved of their pain, 2 had improved relatively, 1 showed only a slight improvement, and in 1 patient no cause was found and no improvement was achieved. Two patients suffered recurrence of pain postoperatively; one had no further complaints after root extirpation following percutaneous thermorhizotomy. Electron microscopic examination of the nerve root and its ganglion revealed focal morphological changes, including proliferation of connective tissue in the endoneurium and the ganglion itself, the formation of onion-bulb-like structures around single axons, discrete signs of myelin damage and axonal degeneration. These morphological changes are possibly the result of a chronic vascular compression.

Focal cranial nerve involvement in chronic inflammatory demyelinating polyneuropathy: clinical and MRI evidence of peripheral and central lesions

Five cases of chronic inflammatory demyelinating polyneuropathy are described in which cranial nerve involvement accompanied a more generalized neuropathy. Clinical, electrophysiological, radiological and nerve biopsy findings are presented. Cranial nerve lesions in this form of polyneuropathy may be related to lesions of the peripheral nerves or of the central nervous system, when they may be accompanied by MRI evidence of more widespread CNS demyelinating lesions. In cases of early onset, the occurrence of focal cranial nerve lesions may serve to distinguish chronic inflammatory from inherited demyelinating polyneuropathies.

T lymphocyte activation antigens in Guillain-Barré syndrome and chronic idiopathic demyelinating polyradiculoneuropathy

Activated circulating T lymphocytes were measured in ten patients with Guillain-Barré syndrome (GBS) and in ten with chronic idiopathic demyelinating polyradiculoneuropathy (CIDP), each paired with an age- and sex-matched healthy control. Activated T cells were identified by double labelling with phycoerythrin-conjugated anti-CD3 antibody and biotinylated antibodies to activation antigens: human leucocyte antigen (HLA)-DR, transferrin receptor (TFR) or interleukin-2 receptor (IL-2R) visualised with an avidin-biotin-fluorescein system. The frequency of activated T cells was increased in the GBS group. The median of the DR-positive T cells in the patients was 3.4% (range 0.5-9.4%), compared with 1.4% (range 0-4.3%) in the controls (P less than 0.01). For TFR the corresponding medians were 3.3% (range 0.5-6.2%) in the patients and 0% (range 0-2.5%) in the controls (P less than 0.01), and for IL-2R 3.7% (range 0-6.0%) in the patients compared with 0% (range 0-2.9%) in the controls (P less than 0.01). In the CIDP group the median percentage of activated T cells was also increased but the differences were less significant: for DR, patients 2.4% (range 0-3.8%), controls 0.5% (range 0-2.0%, P less than 0.05); for TFR, patients 0% (range 0-5.3%), controls 0% (range 0-1.0%, not significant), and for IL-2R, patients 0% (range 0-2.5%), controls 0% (range 0-0.5%, not significant). The activated cells might be directed against microbial antigens encountered during the infection preceding GBS, autoantigens, bacterial antigens encountered during concurrent infection, or a combination of these.

Chronic relapsing idiopathic polyneuropathy with primary axonal lesions

Idiopathic polyradiculoneuropathy with primary axonal lesions is rarely encountered. Two cases are reported with a chronic relapsing course and a fatal outcome. Neuropathological examination of biopsied peripheral nerve in the two patients and in a necropsy case showed loss of myelinated fibres, but neither active demyelination nor inflammatory cells were observed. Acute and chronic relapsing axonal polyradiculoneuropathies appear to be two clinical forms of a peculiar entity different from GBS.

Acquired inflammatory demyelinating polyneuropathies: clinical and electrodiagnostic features

The acquired demyelinating polyneuropathies include acute (AIDP, Guillain-Barré syndrome, GBS) and chronic (CIDP, dysproteinemic) forms which differ primarily in their temporal profile. They are inflammatory-demyelinating diseases of the peripheral nervous system and likely have an immunologic pathogenesis. Although these neuropathies usually have a characteristic presentation, the electromyographer plays a central role in their recognition, since the demyelinating component of the neuropathy, which greatly reduces the differential diagnosis, is often first identified in the electromyography laboratory. In AIDP, the electromyographer, in addition to establishing the diagnosis, can sometimes predict the prognosis. Recognition of the chronic and dysproteinemic forms of acquired demyelinating polyneuropathy is important since they are treatable. The dysproteinemic forms also may be associated with occult systemic disorders that also may require treatment, independent of the neuropathy.

Sural nerve biopsy in chronic inflammatory demyelinating polyradiculoneuropathy

We compared histologic features of sural nerve biopsies in 14 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with those in other forms of neuropathy. In CIDP endoneurial pericapillary cellular infiltrates were found in 4 patients (29%), onion bulbs in 5 patients (36%), and predominant demyelination in 7 patients (50%). None of these abnormalities was specific, but cellular infiltrates and onion bulbs appear to be diagnostically useful when combined with clinical information. To detect macrophage infiltration of myelin, cell nuclei were counter-stained in 20 teased fiber preparations. Nine patients with CIDP had a significantly higher mean number of cells per centimeter of teased fiber than 11 patients with other neuropathies. Despite overlap, significant infiltration of myelin detected by this method suggests CIDP in an appropriate clinical setting.

Chronic recurrent Guillain-Barré syndrome: report of 3 cases

The classical Guillain-Barré syndrome is an acute or subacute polyradiculo-neuropathy whose main clinical features are progressive weakness of the limbs, decrease or absence of tendon reflexes, and sensory changes. Although in most of the cases there is complete recovery in weeks or months, some patients have a slow and progressive relapsing course and present thickening of the peripheral nerves. In this paper we describe three cases of the chronic and relapsing variety of Guillain-Barré syndrome, two of which had prominent hypertrophic changes in the peripheral nerves with onion bulb formations. The clinical and pathological features of this disease are reviewed. The three patients improved with the use of steroids.

Schwann cell responses during regeneration after one or more crush injuries to myelinated nerve fibres

The responses of Schwann cells during regeneration of myelinated nerve fibres were studied ultrastructurally in the distal segment of mouse phrenic nerve after a single or repeated localized crush injury. Chronological observations on nerves after a single crush confirmed the occurrence of myelination of only single regenerating axons among many that appeared in individual Büngner bands. The redundant axon sprouts often showed the structural features of degeneration and decreased in number with time. During the process, supernumerary Schwann cells not related to myelin formation were produced. They commonly failed not only to make a one-to-one relationship with an axon, but they also failed to acquire a new basal lamina of their own. With time, they showed shrinkage of their cytoplasm and became arranged circumferentially around the myelinating axon with unipolar or bipolar cytoplasmic processes. Electron microscopic, quantitative assessment of the nuclear population of Schwann cells following repeated crushes up to four times, clearly indicated a progressive and predominant increase in the number of the supernumerary Schwann cells with the number of crushes. Also, they were found to form separate concentric cytoplasmic lamellae around the myelinating axons, developing structures resembling onion-bulbs. It was concluded that essentially the same regenerating process as that observed after a single crush was repeated following re-crush, thereby resulting in the successive accumulation of supernumerary Schwann cells around a myelinating axon.

A prospective study of acute idiopathic neuropathy. I. Clinical features and their prognostic value

A prospective study in South-East England during 15 months in 1983-1984 recruited 100 patients with acute idiopathic neuropathy. After 12 months 67% had recovered completely, 20% were still significantly disabled and 13% had died. Ten of the 13 deaths were attributable to the neuropathy. The major features in the initial assessment which were associated with persistent disability were the time taken to become bedbound, requirement for ventilation, age greater than 40 years, and small or absent compound abductor pollicis brevis muscle action potentials elicited by stimulation of the median nerve at the wrist. These four variables have been combined in a statistical model to predict outcome for individual patients with acute idiopathic neuropathy.

Multifocal acquired demyelinating neuropathy masquerading as motor neuron disease

We report five patients with pure motor neuropathy characterized by multifocal weakness, muscle atrophy that was sometimes profound, cramps, and fasciculations with relatively preserved reflexes. The clinical picture led to an initial diagnosis of motor neuron disease in all cases, but nerve conduction studies revealed multifocal conduction block confined to motor axons and predominantly involving proximal nerve segments. Routine sensory nerve conduction studies, ascending compound nerve action potentials, and somatosensory evoked potentials were all normal even through nerve segments in which motor conduction was severely blocked. Onset of symptoms was insidious, and progression was indolent. In two cases, after many years of neuropathy, sensory abnormalities developed but remained clinically trivial. These unusual cases probably have the same pathogenesis as previously described patients with persistent multifocal conduction block. Distinction from motor neuron disease is critical, since chronic demyelinating neuropathy may respond to treatment.

Significance of lymphocytes and blood vessel changes for edema formation in polyradiculoneuritis

Human sural nerve biopsies of eight cases with acute, subacute and chronic polyradiculoneuritis were studied by means of immunohistochemistry to characterize the inflammatory infiltrates. In addition, the structural changes of the endoneurial blood vessels were examined by electron microscopy, since both factors are likely to contribute to disturbances of the blood-nerve barrier. By use of six monoclonal antibodies, it was shown that the inflammatory infiltrates in cases with more acute polyradiculoneuritis are predominantly recruited by Leu 3a- and Leu 4-positive T lymphocytes. In more chronic polyradiculoneuritis beside of few Leu 3a-positive and Leu 4-positive T lymphocytes also B cells occurred. Leu M3-positive macrophages were detected in all cases with fluoride myelin degeneration. Since immunoreactivity for antigens of the HLA-D-locus (Leu-HLA-DR and Leu 10) were present on the infiltrating mononuclear cells, it can be postulated that they represent active and immunocompetent cells. Ultrastructurally, the amount of pinocytotic vesicles in the endothelial cells of the endoneurial blood vessels was increased. Moreover, a prominent folding of the luminal and abluminal surface of vascular endothelial cells and diminution of the intercellular tight junctions were observed. These findings appear suitable to explain the increased leakage of serum proteins across the blood-nerve barrier in polyradiculoneuritis sharing general features of cell-mediated immunity.

Neuromuscular diseases associated with human immunodeficiency virus infection

The types of neuromuscular diseases associated with human immunodeficiency virus (HIV) infection are described. Our classification includes: (1) six subtypes of peripheral neuropathies--namely, acute Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, mononeuritis multiplex, an axonal, predominantly sensory, painful polyneuropathy, a sensory ataxic neuropathy due to ganglioneuronitis, and an inflammatory polyradiculoneuropathy presenting as cauda equina syndrome; (2) inflammatory myopathies (e.g., polymyositis); and (3) other less common neuromuscular manifestations, such as type II muscle fiber atrophy and nemaline myopathy. Although the exact incidence of clinical and subclinical neuromuscular diseases in HIV-positive and acquired immunodeficiency syndrome (AIDS) patients is unknown, estimates vary from 15 to almost 50% of such individuals. The type of neuropathy or myopathy related to the specific stage of HIV infection, the pathogenetic mechanisms involved, and effective therapies are discussed. A neuromuscular disease not only occurs in patients with AIDS and AIDS-related complex, but it can coincide with HIV seroconversion or it can be the only clinical indication of a chronic silent HIV infection. Chronic asymptomatic HIV infection should be considered in the differential diagnosis of certain acquired inflammatory polyneuropathies or myopathies. Precautions needed when doing electromyographic studies are discussed.

Chronic experimental allergic neuritis. An electrophysiological and histological study in the rabbit

Ten adult outbred New Zealand white rabbits were inoculated with a single multiportal dose of purified bovine peripheral nerve myelin and Freund's adjuvant containing 500 mg of nerve antigen. Seven animals developed chronic relapsing or progressive disease which was followed by clinical examination for 14 months. Electrophysiological studies showed marked slowing of motor conduction velocity, dispersion of the evoked muscle action potential (MAP) and reduction in amplitude of the MAP derived from distal stimulation. Histological examination of the peripheral nervous system showed at 12 months a marked hypertrophic neuropathy in the nerve roots with well developed onion bulbs, active demyelination and a moderate nerve fibre loss. It is suggested that these animals provide a reliable and predictable model for human chronic inflammatory demyelinating polyneuropathy (CIDP) which should prove valuable for therapeutic trials and studies of pathogenetic mechanisms.

The C57BL mice: an animal model for inflammatory demyelinating polyneuropathy

Recently it has been reported that the C57BL mice can be used as a model of benign monoclonal gammopathy (MG). Since experimental models have until now failed to reproduce specific lesions of human dysglobulinemic polyneuropathies, we decided to investigate the peripheral nerve of these mice. The sciatic nerve and the serum from 14 C57BL mice were examined: 9 of these animals were found to have an IgG, kappa light chain MG, while in the other 5 no abnormalities were detected in the serum. In the 14 mice, features of demyelination were found in certain fibers, as well as onion-bulb formations around other myelinated fibers. Features of active demyelination were found in 10 animals and it must be underlined that three of these had no serum abnormalities. The decrease of the conduction velocities and the temperature coefficients Q10 of the C57BL mice suggest a good correlation between morphological and functional parameters. This strongly suggests that this strain of mice provides a suitable model for inflammatory demyelinating polyneuropathy (IDPN).

High-dose intravenous gammaglobulin for chronic inflammatory demyelinating polyneuropathy

We report our preliminary experience of high-dose intravenous gammaglobulin in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) selected for inefficacy or severe side effects of steroid and immunosuppressive treatment. Our treatment proved safe and effective, reversing the disability of CIDP, the improvement being temporally related to the commencement of intravenous high-dose gammaglobulin. The possible mechanisms of action are discussed.

Abnormalities of central axons in a dysmyelinative rat mutant

The absence of normal myelin from the CNS of the dysmyelinative rat mutant, md, is associated with axonal abnormalities including organelle-poor and organelle-rich spheroids (OPS and ORS, respectively), wrinkling of the axolemma, persistence of glycogen aggregates and vacuoles in cerebellar mossy fiber terminals, and coalescence of synaptic vesicles in terminal boutons of the nucleus interpositus. OPS have a special predilection for medullary pyramid and the axons of Purkinje cells and further differ from ORS in their possession of nematosomes and in their lack of neurofilaments, microtubules, and degenerating mitochondria. Purkinje cells of md fail to increase in size after 30 days postnatal age and, unlike these neurons in normal neonatal rats, may have massed or dispersed granules of cytoplasmic glycogen which persist for at least 86 days postnatally. Morphometric study of axons of medullary pyramid and cervical corticospinal tract at 19-43 days of age shows a shift in frequency to axons of smaller size in md, as compared to age-matched controls, except that approximately 1% of md axons are larger than any encountered in controls. Finally, the pyramidal axons of md at 43 days of age have a significantly larger area of axoplasm occupied by mitochondria than obtains for the control condition. We conclude that the described abnormalities are secondary to the lack of a myelin investment and/or the loss of oligodendrocytes.

Humoral factors in peripheral nerve disease

Humoral factors including soluble substances transported by the blood stream and factors released at a target tissue may play a role in diseases of the peripheral nervous system. Various criteria have to be met in order to accept humoral factors as potential pathogens. In this review these general criteria are discussed, including the evidence provided by plasma exchange therapy, demonstration of circulating or deposited autoantibodies and immune complexes, identification of antigenic molecules, animal model diseases, passive transfer experiments, and the demonstration of circulating factors not directed against specific targets. In acute, chronic, and chronic relapsing inflammatory polyneuropathies, and in the polyneuropathy associated with monoclonal gammopathy, humoral factors have been identified, but their exact pathogenic role is not fully understood. In the Lambert-Eaton myasthenic syndrome, a disorder of the motor nerve terminal, pathogenic IgG-antibodies have been demonstrated by passive transfer experiments. In the experimental animal model disorders, the acute and chronic variants of experimental allergic neuritis, humoral factors including antibodies to myelin basic proteins and galactocerebroside and nonspecific humoral factors may all contribute to the ultimate peripheral nerve damage, but their relative importance in relation to cell-mediated immune reactions is not yet clear.

Inflammatory demyelinating peripheral neuropathies associated with human T-cell lymphotropic virus type III infection

Nine patients with inflammatory demyelinating polyneuropathies (IDP) were found to have human T-cell lymphotropic virus type III (HTLV-III) infection. The 8 men, 6 of whom were homosexual, and 1 woman, a former intravenous drug user, presented with progressive weakness. Two had lymphadenopathy but all were otherwise asymptomatic. Six had chronic IDP and 3 had Guillain-Barré syndrome. In addition to an elevated cerebrospinal fluid (CSF) protein level (mean, 193 mg/dl), most patients had cerebrospinal fluid pleocytosis (mean, 23 cells/mm3), a distinctive feature. All had reduced T4:T8 T-cell ratios. Results of nerve conduction studies were characteristic of demyelination. Nerve biopsies revealed intense inflammatory cell infiltrates and macrophage-mediated demyelination. The patients recovered either spontaneously or following treatment with corticosteroids or plasmapheresis. During a mean interval of 20 months after presentation, only 1 patient had developed acquired immune deficiency syndrome. Patients with HTLV-III infection have disordered immune function, and the mechanism of the development of the IDP is likely to be immunopathogenic. As a result of our experience, we suggest that all patients with IDP be tested for evidence of HTLV-III infection. We also found, although in uncontrolled trials, that treatment with either prednisone or plasmapheresis was followed by clinical improvement; since plasmapheresis is not likely to further depress cell-mediated immunity, we suggest that it be the initial therapy.