Transient immunosuppression: a bridge between infection and the atypical autoimmunity of Guillain-Barré syndrome?

Guillain-Barré syndrome (GBS) is an acute, usually monophasic, disorder of the peripheral nervous system that is assumed to be of immune-mediated pathogenesis. However, several clinical features and experimental findings of GBS are uncharacteristic for an immune-mediated disorder and set this condition apart from other disorders with a putative immune-mediated pathogenesis. These features include, among others, the monophasic nature of GBS, the lack of response to immunosuppressive (unlike immunomodulatory) therapy, the absence of a typical association with immunogenetic background and the inability to establish a valid and relevant animal model. We suggest a comprehensive hypothesis for the pathogenesis of GBS that is based on the assumption that the condition is due to a transient (or occasionally chronic) immune deficiency, as in most cases GBS follows an infection with pathogens known to induce immunosuppression. Such infections may be followed by breakdown of immune tolerance and induction of an immune attack on peripheral nerves. Mounting of the immune-mediated assault might be triggered either by the same infective pathogen or by secondary infection. Clearance of the infection and resumption of a normal immune response and tolerance eventually terminate the immune-mediated damage to the peripheral nerves and enable recovery. This hypothesis assumes that the entire sequence of events that culminates in GBS is due to transient exogenous factors and excludes a significant role for inherent host susceptibility, which explains the monophasic nature of the disorder.

Co-morbidity of Emery-Dreifuss muscular dystrophy and a congenital myasthenic syndrome possibly affecting the phenotype in a large Bedouin kindred

Emery-Dreifuss muscular dystrophy (EDMD) is an X-linked humero-peroneal muscular dystrophy associated with contractures and cardiomyopathy. In a 90 member family, we found 11 affected male individuals, three of whom displayed areflexia and neurogenic electromyographic changes. Muscle biopsy performed in one case demonstrated type grouping suggestive of a neurogenic disorder. These three individuals and another family member, who suffers from mild, static limb weakness but is clinically and genetically unaffected by EDMD showed an abnormal incremental response of over 100% to tetanic stimulation. In contrast, one affected family member showed myopathic features on needle electromyography and no definite pathology in repetitive stimulation studies. The diagnosis of EDMD was established by demonstrating a 1712_1713insTGGGC mutation in the emerin gene. This family apparently expresses co-morbidity of EDMD with an exceptionally mild form of pre-synaptic congenital myasthenic syndrome resembling the Lambert-Eaton myasthenic syndrome (LEMS). The superimposed pre-synaptic disorder may have contributed to the development of the neurogenic features demonstrated in these patients.

Hereditary inclusion body myopathy: the Middle Eastern genetic cluster

BACKGROUND

Recessively inherited hereditary inclusion body myopathy (HIBM) with quadriceps sparing was initially described only in Jews originating from the region of Persia. The recent identification of the gene responsible for this myopathy and the common "Persian Jewish mutation" (M712T) enabled the re-evaluation of atypical phenotypes and the epidemiology of HIBM in various communities in the Middle East.

OBJECTIVE

To test for the M712T mutation in the DNA from HIBM patients in the Middle East.

METHODS

DNA from all suspected HIBM patients was tested for the M712T mutation. Unaffected members of families with genetically proven HIBM were studied too. In the majority of families, haplotype construction with markers spanning the 700-kb region of the HIBM gene was performed.

RESULTS

One hundred twenty-nine HIBM patients of 55 families (Middle Eastern Jews, Karaites, and Arab Muslims of Palestinian and Bedouin origin) were homozygous for the M712T mutation, and all carried the same haplotype. Five clinically unaffected subjects were also homozygous for the common mutation and haplotype, including two older adults (ages 50 and 68 years). Atypical features with this same mutation were marked quadriceps weakness in five patients, proximal weakness only in two patients, facial weakness in three patients, and a muscle biopsy showing perivascular inflammation in one patient.

CONCLUSIONS

The phenotypic spectrum of recessive HIBM is wider than previously described, and the diagnostic criteria for this myopathy must be changed. The Middle Eastern cluster is the result of a founder mutation, with incomplete penetrance, that is approximately 1,300 years old and is not limited to Jews.

Thiamine-responsive acute neurological disorders in nonalcoholic patients

Wernicke's encephalopathy (WE) is most commonly associated with alcoholism, although other causes have also been implicated. In the years 1994-1997, 9 patients with no history of alcohol abuse presented with acute signs of ophthalmoplegia or nystagmus and ataxia which resolved within 48 h after intravenous thiamine. There were 7 women and 2 men aged 17-57 (7 below the age of 30). Precipitating events included vomiting 2, drastic weight-reducing diet 2, renal colic in a postpartum woman 1, colonic surgery 2 and chronic hemodialysis 1. In 2 patients there was no obvious precipitating event but their history was suggestive of a genetic predisposition. Mental changes were slight or absent in all patients and all of them made good functional recovery. These cases suggest that the diagnosis of WE should be considered more often in nonalcoholics in various clinical settings.

Ganglioside agglutination immunoassay for rapid detection of autoantibodies in immune-mediated neuropathy

Elevated levels of serum autoantibodies directed against gangliosides are closely associated with acute and chronic autoimmune neuropathies. An agglutination immunoassay using polystyrene microparticles coated with a total extract of brain gangliosides was used to test patient sera for the presence of anti-ganglioside antibodies. Results were compared with those obtained by ELISA for anti-GM1 and anti-GQ1b ganglioside antibodies. Eight of the twelve sera from patients with multifocal motor neuropathy and seven of the thirteen sera from patients with Guillain-Barré syndrome were positive for the presence of anti-ganglioside antibodies by the ganglioside agglutination immunoassay. The assay compared favorably with the ELISA system in sensitivity and specificity, while requiring a fraction of the time and cost to perform. The new assay can serve as a rapid and effective method for detecting or screening for anti-ganglioside antibodies in patients with acute or chronic immune-mediated neuropathies. It would be particularly useful for detecting antibodies that react with multiple gangliosides, or with minor or as yet uncharacterized gangliosides.

Infection and the etiology and pathogenesis of multiple sclerosis

Multiple sclerosis (MS) currently defies clinical and scientific definitions, and carries a prognosis that remains practically unchanged despite many years of intensive research. Although the prevailing dogma is that MS is an immune-mediated condition, it fulfills none of the criteria of an autoimmune disease. On the other hand, there is enough significant data to suggest that infectious agents(s) could be involved in either direct damage to the white matter or induce inflammatory responses that secondarily affect the brain. Our goal here is to review the data supporting the possibility that infection has a critical role in the disease, examine the list of potential candidates that have been suggested, and outline an approach regarding the potential role of infectious agents in the etiology and pathogenesis of MS.

Lipopolysaccharides of a Campylobacter coli isolate from a patient with Guillain-Barré syndrome display ganglioside mimicry

Campylobacter coli was isolated from a patient with severe, axonal type Guillain-Barré syndrome (GBS). The patient's serum was tested by ELISA for glycolipid antibodies and showed a high titer of IgG antibodies to asialo-GM1 (GA1) and GD3. Campylobacter coli lipopolysaccharide (LPS) was extracted and analyzed by ELISA, immunoblot binding and blocking studies, and found to avidly bind cholera toxin and peanut agglutinin. The LPS from the patient's isolate also induced anti-GA1 antibodies in a rat model. These findings suggest that the LPS from this bacterial isolate contains a ganglioside-like epitope, which most likely resembles GA1. Thus, it appears that ganglioside cross-reactivity is not unique to Campylobacter jejuni and seems to occur in all bacterial isolates from GBS cases so far analyzed.

Oral administration of a dual analog of two myasthenogenic T cell epitopes down-regulates experimental autoimmune myasthenia gravis in mice

Myasthenia gravis (MG) and experimental autoimmune MG (EAMG) are T cell-regulated, antibody-mediated autoimmune diseases. The major autoantigen in MG is the nicotinic acetylcholine receptor (AChR). Two peptides, representing sequences of the human AChR alpha-subunit, p195-212 and p259-271, were previously shown to be immunodominant T cell epitopes in MG patients as well as, respectively, in SJL and BALB/c mice. A dual analog (termed Lys-262-Ala-207) composed of the tandemly arranged two single amino acid analogs of p195-212 and p259-271 was shown to inhibit, in vitro and in vivo, MG-associated autoimmune responses. Furthermore, the dual analog could down-regulate myasthenogenic manifestations in mice with EAMG that was induced by inoculation of a pathogenic T cell line. In the present study, the ability of the dual analog to treat EAMG induced in susceptible C57BL/6 mice by native Torpedo AChR was evaluated. Mice that were diagnosed to have clinical symptoms of EAMG were treated with the dual analog by oral administration, 500 microg per mouse three times a week for 5-8 weeks. Treatment with the dual analog down-regulated the clinical manifestations of the ongoing disease as assessed by the clinical score, grip strength (measured by a grip strength meter), and electromyography. The effects on the clinical EAMG correlated with a reduced production of anti-AChR antibody as well as a decrease in the secretion of interleukin-2 and, more dramatically, interferon-gamma, in response to AChR triggering. Thus, the dual analog is an efficient immunomodulator of EAMG in mice and might be of specific therapeutic potential for MG.

Multiple sclerosis--in need of a critical reappraisal

Multiple sclerosis (MS) is a disease that currently defies clinical and scientific definitions. Despite intensive clinical and basic research, very little is known about its possible cause(s) or pathogenesis, and the course and prognosis of MS practically remain unchanged. The aim of the present article is to outline some of the reasons for the constant failure to improve the therapy of MS. It also attempts to offer several guidelines which may enable a fresh and different approach to this devastating condition.

Murine typhus presenting as subacute meningoencephalitis

Murine typhus is a febrile systemic illness, presenting with headache and undulating fever. Neurological involvement is considered a rare complication. During 1994 and 1995, 34 patients admitted to our hospital were diagnosed as having murine typhus. Five of these patients presented with a syndrome of subacute "aseptic" meningitis or meningoencephalitis. Three had bilateral papilloedema and 2 had focal neurological signs. None had a rash or other systemic findings suggestive of rickettsial disease. The diagnosis was based on serum and cerebrospinal fluid serology and on prompt response to doxycycline therapy. These cases suggest that neurological involvement in murine typhus is more common than previously suspected and that murine typhus should be included in the differential diagnosis of subacute meningitis in endemic areas.

Cefuroxime-induced encephalopathy

We describe four patients who developed an encephalopathic syndrome characterized by obtundation or stupor, myoclonic jerks, and asterixis in association with cefuroxime therapy. Three patients had renal failure. These cases suggest that cefuroxime in overdose or in conventional doses in patients with renal failure can cause a reversible encephalopathy. This syndrome may have been unrecognized because it usually occurs in severely ill patients with additional causes for encephalopathy.

Single amino acid analogs of a myasthenogenic peptide modulate specific T cell responses and prevent the induction of experimental autoimmune myasthenia gravis

Peptide p259-271 of the human acetylcholine receptor alpha-subunit, preferentially stimulates T cells of patients with myasthenia gravis (MG) and is an immunodominant epitope for T cells of BALB/c mice. A p259-271 specific T cell line of BALB/c origin was established and was shown to induce experimental MG in naive mice. Seven analogs of p259-271 were synthesized, and two of them were found to inhibit the p259-271 specific proliferative responses of the line and of p259-271 primed lymph node cells. Moreover, the most efficient inhibitor, analog 262Lys, prevented the MG related manifestations in mice inoculated with the line, and might be of potential value for the treatment of MG.

Induction of anti-GM1 ganglioside antibodies by Campylobacter jejuni lipopolysaccharides

A frequent association exists between acute motor neuropathy, antecedent Campylobacter jejuni (CJ) and anti-GM ganglioside antibodies. Despite the chemical and immunological similarity between CJ lipopolysaccharides (LPS) and GM1, the mechanism of induction of anti-GM1 antibodies is still unclear. We used CJ LPS to immunize rats, mice and immunodeficient mice lacking in NK, CD8+ or T-cell populations. None of these animals developed significant anti-GM1 titers. However, rats immunized with keyhole limpet hemocyanin which contains the cross-reactive sugar epitope Gal(beta1-3)GalNAc developed high titers of IgM anti-GM1 antibodies. This occurred only after these rats were given an intraperitoneal injection of CJ LPS. These results suggest that a glycoprotein antigenic stimulus can induce B-cells which are autoreactive to ganglioside but which remain anergic. A second stimulus with a cross-reactive LPS can then overcome the anergy to induce autoantibody production. A similar mechanism may explain the occurrence of GM1 antibodies in patients after CJ enteritis.

Oxidative stress mediates impairment of muscle function in transgenic mice with elevated level of wild-type Cu/Zn superoxide dismutase

Cases of familial amyotrophic lateral sclerosis (fALS; a neurodegenerative disorder) have been reported in which the gene for Cu/Zn superoxide dismutase (CuZnSOD) was mutated. Several studies with the fALS mutant CuZnSOD in transgenic mice and cells showed that the fALS mutations act through an as yet undefined dominant gain-of-function mechanism. Wild-type CuZnSOD catalyzes the dismutation of superoxide (O(2)(-).) but also produces hydroxyl radicals (.OH) with H(2)O(2) as substrate. Two laboratories have recently demonstrated that the .OH production ability was preferentially enhanced by the fALS mutant CuZnSOD, suggesting that this might be the function gained in fALS. In this study, we used transgenic CuZnSOD (Tg-CuZnSOD) mice with elevated levels of CuZnSOD to determine whether overexpression of wild-type CuZnSOD was also associated with increased .OH production and impaired muscle function. Enhanced formation of .OH was detected, by spin trapping, in brain and muscle extracts of the Tg-CuZnSOD mice. Three independently derived Tg-CuZnSOD lines showed muscle abnormalities, reflected by altered electromyography (EMG) and diminished performance in the rope grip test. After treatment with paraquat (PQ), a widely used herbicide and O(2)(-).-generating compound, muscle disability significantly deteriorated in Tg-CuZnSOD mice but not in control mice. The results indicate that elevated levels of CuZnSOD cause indigenous long-term oxidative stress leading to impairment of muscle function. These findings may provide valuable clues about the concurred role of indigenous oxidative stress and exogenous agents in the etiology of sporadic ALS and several other neurodegenerative diseases in which a specific subset of neurons is affected.

A peptide composed of tandem analogs of two myasthenogenic T cell epitopes interferes with specific autoimmune responses

Myasthenia gravis (MG) is a T cell-regulated, antibody-mediated autoimmune disease. Two peptides representing sequences of the human acetylcholine receptor alpha-subunit, p195-212 and p259-271, were previously shown to stimulate peripheral blood lymphocytes of patients with MG and were found to be immunodominant T cell epitopes in SJL and BALB/c mice, respectively. Single amino acid substituted analogs of p195-212 (analog Ala-207) and p259-271 (analog Lys-262) were synthesized. We showed that analogs Ala-207 and Lys-262 inhibited, in vitro and in vivo, the proliferative responses of T cell lines specific to the relevant peptide and lymph node cells of mice immunized to p195-212 and p259-271, respectively. To inhibit T cell responses to both peptides (p195-212 and p259-271), we synthesized dual analogs composed of the tandemly arranged two single (Ala-207 and Lys-262) analogs (dual analog) either sequentially (Ala-207-Lys-262) or reciprocally (Lys-262-Ala-207). In the present study, we report that both dual analogs could bind to major histocompatibility complex class II molecules on antigen-presenting cells of SJL and BALB/c mice. Analog Lys-262-Ala-207, which bound more efficiently to major histocompatibility complex class II molecules, was found to inhibit the proliferative responses of both p195-212- and p259-271-specific T cell lines. Furthermore, the analog inhibited the in vivo priming of lymph node cells of both SJL and BALB/c mice when administered i.v., i.p., or per os. The dual analog Lys-262-Ala-207 could also immunomodulate myasthenogenic manifestations in mice with experimental autoimmune MG induced by inoculation of a pathogenic T cell line. Thus, a single peptide that is composed of analogs to two epitope specificities can be used to regulate T cell responses and disease associated with each epitope.

Lambert-Eaton myasthenic syndrome (LEMS) in association with lymphoproliferative disorders

LEMS is a presynaptic neuromuscular junction disorder typically associated with small cell lung carcinoma. The characteristic electrophysiological abnormality is a low amplitude compound muscle action potential that shows a marked increment after short maximal contraction or brief tetanic nerve stimulation. Here we describe 3 patients who had LEMS in association with lymphoproliferative disorder. The first patient had Castleman's syndrome with typical clinical and electrophysiological features of LEMS, which responded partially to treatment with 3-4-diaminopyridine. The second patient was a 7-year-old boy who had an unusual acute onset of LEMS associated with relapse of his Burkitt's leukemia. The third patient was a 60-year-old woman with non-Hodgkin's lymphoma. These 3 patients (together with 6 additional patients identified in the literature) lead us to suggest that lymphoproliferative diseases are another, hitherto unrecognized, type of malignancy associated with LEMS. Thus, any patient with these malignancies and unexplained muscle weakness should have electrophysiological evaluation for LEMS.

Keyhole limpet hemocyanin contains Gal(beta 1-3)-GalNAc determinants that are cross-reactive with the T antigen

Keyhole limpet hemocyanin (KLH) is widely used as a carrier molecule to enhance immune responses to administered antigens, and for immunotherapy of bladder and renal carcinoma. In the present study we show, using lectin and antibody binding studies, that native KLH contains Gal(beta 1-3)GalNAc-bearing oligosaccharides, and that immunization with KLH in Lewis rats induces the production of anti-Gal(beta 1-3) GalNAc antibodies. This might explain the beneficial effect of KLH in bladder cancers that express cross-reactive Gal(beta 1-3)GalNAc determinants or the T antigen.

Axonal degeneration accompanied by conduction block induced by toxin mediated immune reactivity to GM1 ganglioside in rat nerves

Immune mechanisms have been implicated in the pathogenesis of motor neuropathy with conduction blocks and of acute axonal neuropathy, and GM1 ganglioside has been identified as a potential target antigen. In these experiments, the B subunit of cholera toxin (CT-B), which binds to GM1, was used to target an antibody response to GM1 in peripheral nerve. CT-B was injected into the sciatic nerves of rats, in which anti-CT antibodies were previously induced by immunization, so that the circulating anti-CT-B antibodies bound to the CT-B-GM1 complex in the nerve. Electrophysiological studies revealed the presence of conduction block, and in pathological studies there was axonal degeneration with little demyelination. Control animals, in which keyhole limpet hemocyanin was substituted for CT, did not develop conduction block or axonal degeneration. These studies indicate that antibodies directed at GM1 sites in peripheral nerve could cause an axonal neuropathy with conduction block.

Motor neuron disease and monoclonal gammopathy

In a study to determine the prevalence of monoclonal gammopathy (MG) among patients with motor neuron disease (MND), 6 out of 56 (10.7%) were found to have a monoclonal paraprotein. Of these 6 patients, 4 had an IgG and 2 had an IgA paraprotein. The clinical syndromes consisted of amyotrophic lateral sclerosis in 2 patients, lower motor neuron syndrome with preserved reflexes in at least one limb in 3 patients, and motor neuropathy with multifocal conduction block in 1 patient. The presence of gammopathy appears to correlate with the absence of marked upper motor neuron involvement and with elevated CSF protein concentration. An underlying malignant disorder was ruled out in all 6 patients, and they were considered to have MG of undetermined significance (MGUS). In a control group of 121 age-matched patients with other neuroimmunological disorders, 5 patients (4.13%) had MG. Four of these had gammopathy associated with malignant myeloma, and 1 had MGUS. These results support previous reports of increased prevalence of MGUS in patients with MND and suggest that an autoimmune mechanism may play a role in the disease.

Immunomodulation of experimental autoimmune myasthenia gravis with linomide

Linomide, a synthetic immunomodulator, increases natural killer (NK) activity and markedly activates several lymphocyte populations in both experimental animals and humans. It has been shown to ameliorate the autoimmune manifestations of lupus-like disease in MRL/lpr mice and the clinical and pathological signs of acute and chronic-relapsing experimental autoimmune encephalomyelitis (EAE) in SJL/J mice. We examined the effect of linomide (100 mg/kg/day; administered in drinking water) on rabbits and rats with experimental autoimmune myasthenia gravis (EAMG). Following immunization with Torpedo acetylcholine receptor (AChR), all control rabbits developed clinical signs of severe weakness and exhibited a decrement of muscle action potential upon repetitive stimulation. In contrast, mild signs of weakness appeared in only two of five linomide-treated rabbits, with EMG borderline positive in one of them. Booster immunization with Torpedo AChR induced severe relapse and death in two EAMG control rabbits, whereas the two linomide-treated animals remained free of myasthenic symptoms. The serum level of antibodies against both Torpedo and rat AChR were markedly suppressed in the linomide-treated animals. Similar inhibition of clinical signs of EAMG was observed in the EAMG rat model. Furthermore, the in vitro proliferative response of lymph node cells to Torpedo AChR and the purified protein derivative of Mycobacterium tuberculosis was significantly lower in the linomide-treated EAMG rats than in the controls. Linomide may constitute a new immunomodulating agent for the treatment of myasthenia gravis.

Suppression of experimental autoimmune encephalomyelitis by cannabinoids

The effect of delta 8-THC on experimental autoimmune encephalomyelitis (EAE) was examined. delta 8-THC is an analogue of delta 9-THC, the psychoactive component of marijuana. It is more stable and less psychotropic than delta 9-THC and like the latter it binds to the brain cannabinoid receptor. Two strains of rats were inoculated for EAE, and delta 8-THC (40 mg/kg) was administered for up to 21 days. delta 8-THC significantly reduced the incidence and severity of neurological deficit in both rat strains. The beneficial influence of delta 8-THC only occurred on oral administration and not with parenteral injection. Serum corticosterone levels were twofold elevated in rats with EAE chronically treated with delta 8-THC. These results suggest that suppression of EAE by cannabinoids may be related to their effect on corticosterone secretion.

Fine specificity of T cell lines and clones that are capable of inducing autoimmune manifestations in mice

Myasthenia gravis is a T-cell-regulated, antibody-mediated autoimmune disease. The synthetic peptides p195-212 and p259-271, which represent sequences of the human acetylcholine receptor alpha-subunit, preferentially stimulated T cells of patients with myasthenia gravis and were found to be immunodominant T cell epitopes in SJL and BALB/c mice, respectively. Therefore, we established a p195-212-specific T cell line from SJL mice and a p259-271-specific T cell line from BALB/c mice. N- and C-terminal truncated and/or extended peptides differed in their ability to stimulate proliferative responses of the lines and of their derived clones. Activated cells of the lines were inoculated into naive syngeneic mice. In both strains of mice, peptide-specific antibodies and antibodies to the murine acetylcholine receptor were detected. In addition, decremental compound muscle action potentials consistent with impairment of neuromuscular transmission were recorded from the line-inoculated mice. Thus, these T cell lines, clones, and epitopes constitute a useful model for investigating T cell pathogenicity in autoimmune manifestations related to myasthenia gravis.

Monoclonal IgM antibodies to GM1 and asialo-GM1 in chronic neuropathies cross-react with Campylobacter jejuni lipopolysaccharides

We tested monoclonal IgM anti-GM1 and asialo-GM1 antibodies from 6 patients with chronic motor neuropathies for binding to lipopolysaccharides (LPS) from three stains of Campylobacter jejuni. Four of the 6 patients showed strong reactivity with LPS from at least one of the three C. jejuni strains tested as shown by enzyme-linked immunosorbent assay or western blot. Preabsorption with GM1 or asialo-GM1, or blocking with cholera toxin, prevented antibody binding to LPS. These studies indicate that human anti-GM1 or anti-asialo-GM1 antibodies cross-react with LPS from certain strains of C. jejuni, and that bacterial LPS might provide antigenic stimuli for the activation of B cells expressing anti-GM1 antibodies.

Variable effect of calcium channel blockers on the decremental response in experimental autoimmune myasthenia gravis

We tested the effect of intravenous administration of verapamil and nimodipine on the decremental response in rabbits with experimental autoimmune myasthenia. Nimodipine produced an immediate augmentation of the decremental response to 3-Hz nerve stimulation, which lasted about 30 min. In contrast, verapamil caused marked amelioration of the decrement beginning 30 min after injection. Our findings are consistent with previous reports suggesting that verapamil has a presynaptic effect of enhanced acetylcholine release at the neuromuscular junction. Since evaluation of a drug effect in vivo in animals with experimental autoimmune myasthenia gravis may be more pertinent to its effect on patients with myasthenia gravis (MG), verapamil might prove to be safer in MG than nimodipine. However, due to the additional effects of calcium channel blockers, the safety of their use in myasthenia gravis cannot be inferred from the experimental results.

Synthesis of antibodies against measles virus and myelin by in vitro stimulated B-cells derived from patients with subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) patients carry persistent measles virus infection in the brain. Furthermore, the blood lymphocytes contain viral RNA. Lymphocytes derived from 6 SSPE patients were stimulated with Epstein-Barr virus (EBV). Production of antibodies against measles virus of the IgG isotype was detected in the supernatants of cell cultures of all patients, regardless of the disease's activity, duration or interferon therapy. In contrast, only some of these cell cultures also produced antibodies against myelin.

Multifocal motor nerve conduction abnormalities in amyotrophic lateral sclerosis

Motor nerve conduction in motor neuron disease is considered normal until the terminal stages of the disease, a notable exception being lower motor neuron syndrome associated with anti-glycolipid antibodies. We reviewed the electrophysiological findings in all our patients who were diagnosed as having amyotrophic lateral sclerosis (ALS) during the last 6 years. Six patients, clinically indistinguishable from "classical" ALS patients, out of 31 (19%) displayed motor nerve conduction abnormalities. The most consistent finding, occurring in all 6, was prolonged distal latency or reduced conduction velocity in the distal segment of the median nerve, with normal sensory conduction, suggesting possible pressure proneness of motor nerve fibers in ALS. Additional abnormalities included multifocal motor conduction slowing (3 patients), and conduction blocks (4 patients). None of the patients had paraproteinemia and anti-GM1 and anti-GD1a antibodies were not detected. Thus, a subgroup of clinically indistinguishable ALS patients may have multifocal motor nerve conduction abnormalities, indicating motor nerve fiber involvement. The etiology and pathogenesis of the peripheral nerve involvement are presently unknown.

In vitro synthesis of antibodies to myelin antigens by Epstein-Barr virus-transformed B lymphocytes from patients with neurologic disorders

Anti-myelin antibodies can be found in sera from patients with neurologic disorders of suspected immune-mediated pathogenesis such as multiple sclerosis and inflammatory polyneuropathies. However, the specificity of these findings is controversial. In the present study, in vitro synthesis of antibodies to myelin components was compared to their presence in sera in diverse neurological disorders. Epstein-Barr virus was used to activate B lymphocytes for in vitro antibody production. Anti-myelin basic protein and anti-galactocerebroside antibodies were secreted in vitro by B lymphocytes derived from patients with neurological disorders of various etiologies and pathogenetic mechanisms. Anti-myelin basic protein antibodies were detected in many more cell culture supernatants than in sera from the same patients. In vitro secretion of antibodies to myelin antigens, as well as the presence of these antibodies in body fluids, are apparently non-specific for disease type and may be secondary to neural tissue damage.

Aggravation of human and experimental myasthenia gravis by contrast media

After observing a 72-year-old myasthenic patient develop an acute myasthenic exacerbation following the administration of routine diagnostic IV contrast material, an observation rarely described in the literature, we used the experimental autoimmune myasthenia gravis model in rabbits injected with a contrast agent to simulate the situation. There was significant worsening of the decremental response to 3 Hz repetitive nerve stimulation from 40 +/- 29% to 55 +/- 27% following the IV administration of contrast agent at doses similar to those used in humans. IV calcium partially reversed this aggravation. Caution is merited when myasthenic patients are administered contrast media.

Citrate-induced impairment of neuromuscular transmission in human and experimental autoimmune myasthenia gravis

Two patients who underwent plasmapheresis for severe myasthenia gravis showed marked exacerbation of myasthenic weakness at the end of exchange sessions, in which citrate was used for anticoagulation. In one patient, improvement occurred after the administration of calcium but not after edrophonium. In rabbits and in rats with experimental autoimmune myasthenia gravis, decremental muscle response to 3 Hz repetitive nerve stimulation worsened significantly after injection of the citrate anticoagulant. The worsened neuromuscular transmission defect was reversed by the administration of calcium. When used for anticoagulation, citrate reduces serum ionized calcium levels and thus may aggravate myasthenic weakness and endanger patients during or immediately after plasmapheresis.

In vitro synthesis of antibodies to acetylcholine receptor by Epstein-Barr virus-stimulated B-lymphocytes derived from patients with myasthenia gravis

Peripheral blood lymphocytes and B-cells were obtained from patients with myasthenia gravis and stimulated in vitro with either pokeweed mitogen or Epstein-Barr virus (EBV), respectively. EBV stimulation of B-cells caused a production of antibodies to acetylcholine receptor in 15 of the 25 myasthenia gravis patients: the EBV stimulation of B-cells was more effective in this regard than the pokeweed mitogen stimulation of peripheral blood lymphocytes. The in vitro synthesis of anti-acetylcholine receptor antibodies was found to be positively correlated with both the patients' sera antibody titers and with the disease severity.

Intraventricular interferon treatment for subacute sclerosing panencephalitis

Three children with subacute sclerosing panencephalitis (SSPE) were treated with alpha-interferon. Medication was administered via an Ommaya reservoir into the cerebral ventricular system over a period of 13 to 24 months in increasing amounts up to 1.0 x 10(6) IU twice weekly. Mild clinical improvement in two children and a stable course in the third were associated with improvement of electroencephalographic recordings in all patients and a decrease in antimeasles antibodies in the cerebrospinal fluid of two. The small number of patients does not enable us to determine whether this course was the natural history of SSPE in our patients or whether it was induced by treatment, yet it seems that intraventricular interferon treatment can modify the course of SSPE.

Relapse of multiple sclerosis following acute allergic reactions to plasma during plasmapheresis

In a small pilot study of plasmapheresis in chronic progressive multiple sclerosis, two patients suffered relapses following an acute allergic reaction to plasma. It is suggested that allergic reactions may have played a role in the exacerbation and recommended that fresh frozen plasma be avoided in therapeutic trials for multiple sclerosis.

Fulminant subacute sclerosing panencephalitis in association with pregnancy

Subacute sclerosing panencephalitis developed during pregnancy in a 27-year-old woman and immediately after delivery in an 18-year-old woman. In both, disease took an acute and fulminant course culminating in a vegetative state within several weeks. It is suggested that the relative older age of disease presentation and the unusually rapid neurologic deterioration were partially due to immunologic and hormonal alterations of pregnancy.