Humoral and cellular immune responses to myelin protein peptides in chronic inflammatory demyelinating polyradiculoneuropathy.

OBJECTIVES: Evidence that chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease was sought, by studying cellular and humoral immune responses to peripheral nerve myelin proteins. METHODS: 40 CIDP, 36 healthy control subjects (HC) and subjects with non-immune mediated neuropathies (other neuropathies, ON) for antibodies were studied by ELISA and cellular responses by cytokine ELISPOT (INF gamma, IL10) and ELISA (IL17) to synthetic peptides representing P0, P2 and PMP22. RESULTS: Antibodies to P0, P2 or PMP22 peptides were detected in only a minority of CIDP, both not treated (nT-CIDP) and treated (T-CIDP). IgG antibodies to P2(80-105) were significantly more frequent in CIDP than in HC (4/30 vs 0/32; p<0.05) but the difference from ON (1/25) was not significant. In ELISPOT assays, IFN gamma was detected at a low frequency in CIDP and did not differ from HC or ON. In contrast, IL10 responses against P2(1-85) were more frequent in nT and T-CIDP (7/24 and 3/16) than HC (0/36; p<0.001 and p<0.05, respectively). The production of IL17 in cell-culture supernatants was not increased. CONCLUSIONS: Antibodies to non-conformational antigenic epitopes of myelin proteins rarely occur in CIDP. None of the myelin protein peptides elicited IFN gamma responses, but P2 elicited IL10 responses significantly more often in CIDP patients than in controls. This reactivity may be part of an antigen-specific Th2 type pathogenetic or regulatory mechanism or represent a transitory epiphenomenon due to nerve damage. In our study, P2 was the protein antigen most likely to be involved in the aberrant immune responses in CIDP.

Immune responses to myelin proteins in Guillain-Barré syndrome.

BACKGROUND: Potential target autoantigens in the demyelinating form of Guillain-Barré syndrome (GBS) include the myelin proteins PMP22, P0 and P2. METHODS: We investigated immunoreactivity to P0, P2 and PMP22 proteins in 37 patients with GBS and 32 healthy controls. RESULTS: Antibodies to PMP22 or P0 peptides were detected at presentation in only 5 out of 37 patients. In ELISPOT assays, blood mononuclear cells from 15 out of 24 patients with GBS, but none of the control subjects, produced interleukin-10 (IL-10) in response to peptides from proteins P0, P2 or PMP22 (p = 0.0003). The cells from only two patients produced interferon-gamma (IFN gamma). The cells from 11 patients with GBS had increased IL-10 responses to peptides representing sequences from the extracellular domains of PMP22 before intravenous immunoglobulin (IVIg) treatment (p = 0.006). The cells from 11 patients with GBS, including 7 who responded to the extracellular domains of PMP22, had increased IL-10 responses to the intracellular domain of P0 before (p = 0.005) and those from 9 patients after they had been treated with IVIg (p = 0.01). CONCLUSIONS: Antibodies to P0 and PMP22 protein peptides do occur in GBS but are uncommon. Circulating mononuclear cell IFN gamma responses to P0, P2 and PMP22 myelin protein peptides are rare, but IL-10 responses occur significantly more often than in normal subjects. They might be part of a harmful pathogenetic process or represent a regulatory response.

Characterization of matrix metalloproteinases in denervated muscle.

In a nerve crush model of denervation, we examined muscle matrix metalloproteinase (MMP) expression, localization and activity. In normal muscle, MMP mRNA levels were low, and immunohistochemically MMPs were distributed around the muscle fibre with MMPs-3, -7 and -9 also staining at the neuromuscular junction. Seven days after nerve crush, muscle MMP immunoreactivity, especially MMP-12 and MMP-14, became irregularly distributed. At 20 days reinnervation of the muscle was observed, and some restitution of the normal pattern of immunoreactivity was noted concomitant with a higher level of MMP mRNA expression. In situ zymography showed that MMP activity was very weak in normal muscle whereas it was increased up to 40 days following denervation. Our results suggest that MMPs in muscle are involved in the tissue changes following denervation. Further experiments are required to test the hypothesis that MMP inhibition may be beneficial in protecting muscle from excessive remodelling following denervation and therefore improve reinnervation.

A controlled investigation of the cause of chronic idiopathic axonal polyneuropathy.

To investigate the aetiology of chronic idiopathic axonal polyneuropathy (CIAP), 50 consecutive patients were compared with 50 control subjects from the same region. There were 22 patients with painful neuropathy and 28 without pain, 26 with sensory neuropathy and 24 with sensory and motor neuropathy. The typical picture was a gradually progressive sensory or sensory and motor neuropathy. It caused mild or sometimes moderate disability, and reduced the quality of life. There was no evidence that alcohol, venous insufficiency, arterial disease or antibodies to peripheral nerve antigens played a significant part. There was a possible history of peripheral neuropathy in the first or second-degree relatives of six patients and no controls (P = 0.01), and claw toes were present in 12 patients and four controls (P = 0.03). Thirty-two per cent of the patients and 14% of the controls had impaired glucose tolerance or fasting hyperglycaemia but, after adjusting for age and sex, the difference was not significant (P = 0.45), even in the painful neuropathy subgroup. The mean (SD) fasting insulin concentrations were significantly (P = 0.01) higher in the patients [75.9 (44.4) mmol/l] than the controls [47.3 (37.9) mmol/l], and the mean was higher still in the painful neuropathy subgroup [92.2 (37.1) mmol/l] (P < 0.0001). However, insulin resistance as assessed using the homeostasis model assessment formula was not significantly greater in the patients, even in those with pain, than the controls. After adjustment for body mass index as well as age and sex, there was no significant difference in the serum cholesterol concentrations, but there were significantly higher triglyceride concentrations in the patients [mean 1.90 (1.41) mmol/l] than the controls [mean 1.25 (0.79] mmol/l) (P = 0.02). In the patients with painful peripheral neuropathy, the mean triglyceride concentration was 2.37 (1.72), which was even more significantly greater compared with the controls (P = 0.003). In conclusion, CIAP is a heterogeneous condition. A logistic regression analysis identified environmental toxin exposure and hypertriglyceridaemia, but not glucose intolerance or alcohol overuse as significant risk factors that deserve further investigation as possible causes of CIAP.

Paraneoplastic "stiff person syndrome" with metastatic adenocarcinoma and anti-Ri antibodies.

A 43-year-old woman presented with clinical and electrophysiologic features of stiff person syndrome (SPS), without abdominal or lumbar paraspinal muscle involvement. Investigations revealed metastatic adenocarcinoma of the lung with positive anti-Ri antibodies. Her clinical condition improved with diazepam, baclofen, tizanidine, and palliative chemotherapy. Screening for an underlying malignancy and anti-Ri antibodies should be considered in patients with SPS when clinical presentation is atypical.

Characterisation of matrix metalloproteinases and the effects of a broad-spectrum inhibitor (BB-1101) in peripheral nerve regeneration.

The effect of treatment with a broad-spectrum inhibitor (BB1101) of the matrix metalloproteinases (MMPs) on nerve regeneration and functional recovery after nerve crush was examined. Drug treatment had no effect on latency but from 63 days the compound muscle action potential was significantly increased and was no different to that in the sham-operated controls at 72 days. Levels of MMP mRNA expression, and the localisation and activity of MMP proteins, were examined in rats for a 2 month period following a nerve crush injury, and compared with sham-operated controls. The mRNA of all the MMPs studied was up-regulated by 5-10 days after nerve crush, and they remained up-regulated for 40-63 days, except for MMP-9 which was down-regulated by 10 days. MMP immunoreactivity was localised to Schwann cells, macrophages and endothelial cells, and with the exception of membrane type 1-MMP (MT1-MMP), it was more intense after nerve crush compared with sham-operated controls. Regenerating axons showed immunoreactivity for MMP-2 and MMP-3. In situ zymography confirmed that the activity of MMPs in the nerve was increased following crush but that the activity was greatly reduced in rats treated with BB-1101. Thus despite the inhibition of MMPs by BB-1101, the drug did not appear to essentially affect nerve degeneration or regeneration following nerve crush but that it could be beneficial in promoting the more effective reinnervation of muscles possibly by actions at the level of the muscles.

Haemophilus influenzae as a possible cause of Guillain-Barré syndrome.

Recent reports have contained conflicting results on the relationship between antecedent Haemophilus influenzae infection and Guillain-Barré syndrome (GBS). To investigate the prevalence of H. influenzae infection in GBS patients in a British population, we carried out a retrospective study with 62 consecutive GBS patients and 63 normal controls of similar age and sex. Whole bacteria of both encapsulated and nonencapsulated strains of H. influenzae were employed as antigens in an enzyme-linked immunosorbent assay (ELISA) for anti-H. influenzae IgG, IgM and IgA antibodies. Elevated antibodies of two or three classes were found in one GBS patient and none in the normal controls. Six GBS patients had IgG antibodies against nonencapsulated H. influenzae compared with only one in the normal control group (p=0.06). Western blot for IgG antibody showed that all the sera with IgG antibodies recognized the lipopolysaccharide (LPS) of both strains of H. influenzae. Antiganglioside GM1 antibody was not associated with anti-H. influenzae antibody in our study. Absorption with encapsulated or nonencapsulated H. influenzae, Campylobacter jejuni and Escherichia coli before testing on Western blot showed that only nonencapsulated H. influenzae absorbed the anti-LPS antibodies. In conclusion, there is a possible but rare association of GBS with nonencapsulated H. influenzae in the UK.

A variant of multifocal motor neuropathy with acute, generalised presentation and persistent conduction blocks.

OBJECTIVE: Multifocal motor neuropathy with persistent conduction blocks is classically described as a chronic neuropathy with progressive onset, and acute forms have not previously been characterised. We report four cases of severe motor impairment with acute and generalised onset and with persistent motor conduction blocks. PATIENTS AND RESULTS: An acute tetraparesis with diffuse areflexia but little or no sensory disturbance was the clinical picture. Serial electrophysiological tests showed persistent multifocal motor conduction blocks with absent F waves in most tested motor nerves. No or minor abnormalities of the sensory nerve action potentials were observed. Cerebrospinal fluid contained normal or mildly increased protein levels (<1 g/l) without cells. Campylobacter jejuni serology was negative in three patients and consistent with past infection in one patient. Anti-ganglioside antibodies were positive in three patients. A five day course of intravenous immunoglobulins produced nearly complete symptom resolution in three patients and was ineffective in one patient. CONCLUSION: Because of the persistence of multifocal motor conduction blocks for several weeks or months as the isolated electrophysiological feature, these cases could not be consistent with Guillain-Barré syndrome or chronic inflammatory demyelinating polyneuropathy. They suggest an original variant of multifocal motor neuropathy with an acute and generalised initial presentation and persistent motor conduction blocks affecting all four limbs.

Effects on axonal conduction of anti-ganglioside sera and sera from patients with Guillain-Barré syndrome.

The efficacy of plasma exchange as a therapy for Guillain-Barré syndrome (GBS) suggests that humoral factors might contribute to the axonal conduction block responsible for the major symptoms of the disease. To explore this possibility, we have applied sera to rat spinal roots in vitro while monitoring axonal conduction. Neither fresh sera from 12 patients with GBS or Miller-Fisher syndrome (MFS), nor serum from rabbits immunised with Campylobacter jejuni from patients with GBS, MFS or gastroenteritis were effective in causing acute conduction block, despite the presence of antibodies to gangliosides GD3, GM1, GQ1b and GT1a. Potential explanations are advanced.

Intravenous immunoglobulin modulates lymphocyte CD54 and monocyte FcgammaRII expression in patients with chronic inflammatory neuropathies.

We studied the expression of different lymphocyte and monocyte cellular determinants involved in leukodiapedesis and antigen presentation in 10 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN) with persistent conduction blocks before intravenous immunoglobulin (IVIg), immediately after infusion of IVIg and 1 week after infusion. We observed a decrease of T lymphocytes expressing ICAM-1 (CD54) immediately after infusion in 8 out of 10 patients (p<0.04) with a return to pretreatment values after 1 week. The monocytes showed an increase in CD14(+) cells and CD14(+) FcgammaRII inhibitory receptor positive cells, no change in the number of CD14(+) FcgammaRIII activation receptor cells, and an increase in the FcgammaRII/FcgammaRIII ratio on monocytes 1 week after IVIg. Thus, the mechanism of action of IVIg in both CIDP and MMN may involve inhibition of T cell transmigration and modulation of antigen presentation capacities through FcgammaR expression.

Accumulation of immunoglobulin across the 'blood-nerve barrier' in spinal roots in adoptive transfer experimental autoimmune neuritis.

At the onset of Guillain-Barré syndrome, disruption of diffusion barriers, such as the blood-nerve barrier, probably increases the exposure of spinal roots and peripheral nerves to macromolecules, some of which might be pathogenic. As a measure of such disruption, we measured the accumulation in the endoneurium of spinal roots and sciatic nerve of systemically administered 125I-labelled immunoglobulin in adoptive transfer experimental autoimmune neuritis (AT-EAN) in the rat. AT-EAN is a model of Guillain-Barré syndrome, induced by injection of activated T lymphocytes sensitized to myelin P2 protein. Immunoglobulin accumulation was expressed as counts/min/mg in fixative-perfused roots as a percentage of that in serum, measured 24 h after intraperitoneal injection of 0.1 micro Ci 125I-labelled immunoglobulin. Immunoglobulin accumulation in the roots of normal rats was 3 +/- 1% (mean +/- SE), but this first increased 3(1/2) days after cell injection, peaked at 22 +/- 2% on day 4(1/2), and declined to normal by day 8. T lymphocytes and polymorphonuclear leucocytes first appeared within the endoneurium at day 3(1/2), and macrophages and a few erythrocytes at day 4. Neurological deficit appeared on day 4 and was maximal on day 6. Demyelination and axonal degeneration began at day 5. The first abnormality detected in AT-EAN was a rapid increase in the passage of immunoglobulin into spinal roots, together with endoneurial infiltration of T lymphocytes and polymorphonuclear leucocytes. Accumulation of immunoglobulin was maximal during the worsening of neurological deficit, and declined rapidly before the onset of neurological recovery.

Efficacy of leukemia inhibitory factor in experimental autoimmune neuritis.

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that exerts neurotrophic and myotrophic actions. We have investigated the effect of LIF in experimental autoimmune neuritis (EAN), an animal model of Guillain-Barré syndrome (GBS). Treatment with LIF at the onset of the disease showed a slight, but not significant, improvement in the clinical course but no effect on nerve histology.

Patients with progressive multiple sclerosis have elevated antibodies to neurofilament subunit.

OBJECTIVE: The cause of axonal loss, an important contributor to disability in MS, is poorly understood. This study investigated whether progression in MS is associated with CSF antibodies to the 68-kd light neurofilament subunit (NF-L), an axonal cytoskeletal protein, and compared this with antibodies against tubulin and the heavy neurofilament subunit (NF-H). METHODS: IgG to NF-L, tubulin, and NF-H was measured by immunoassay in matched CSF and serum samples from patients with relapsing-remitting MS (RRMS; n = 39), primary progressive MS (PPMS; n = 10), and secondary progressive MS (SPMS; n = 18); patients with other inflammatory (n = 21) and noninflammatory (n = 40) neurologic diseases; and healthy controls (n = 12). Immunocytochemistry was performed to assess antibody binding to human brain sections, and isoelectric focusing with immunoblotting was performed to assess oligoclonal anti-NF-L production. RESULTS: Intrathecal production of anti-NF-L antibodies was significantly elevated in PPMS and SPMS. In contrast, there were no significant differences in CSF levels of antibodies to tubulin or NF-H between the groups. Anti-NF-L, antitubulin, and anti-NF-H levels correlated with the duration of disease before lumbar puncture and Expanded Disability Status Scale levels. Immunocytochemistry demonstrated binding of CSF or serum antibodies to axonal or neuronal components in six of seven RRMS patients, seven of seven PPMS patients, and eight of 10 SPMS patients tested. Isoelectric focusing demonstrated independent CSF oligoclonal bands reactive with NF-L in six of 13 specimens tested. CONCLUSIONS: Anti-NF-L antibodies seem to be raised in progressive MS and may serve as a marker for axonal loss and disease progression. They may contribute to axonal loss and the accumulation of disability.

Immunological study of hereditary motor and sensory neuropathy type 1a (HMSN1a).

OBJECTIVES: Fifty three patients were studied to investigate whether autoimmune or inflammatory mechanisms could explain the phenotypic heterogeneity of patients with hereditary motor and sensory neuropathy type 1a (HMSN1a). METHODS: Serum samples were examined for antibodies to peripheral nerve myelin protein 22 (PMP22), ganglioside GM1 and cauda equina homogenate, and interleukin-6 (IL-6) and soluble tumour necrosis factor receptor 1 (sTNF R1) concentrations. Serological results were compared with those from patients with other neuropathies (ONPs, n=30) and with normal subjects (n=51). RESULTS: In the group as a whole, no relation emerged between clinical severity and any immune parameters. Immunohistochemical examination of four sural nerve biopsies did not show significant inflammatory infiltration. In a subset of 12 patients who experienced stepwise progression of disease, there was a trend towards a higher proportion having anti-PMP22 antibodies (33% v 15% of those with gradual disease progression, 3% ONPs, and no normal controls) and complement fixing antibodies to human cauda equina (25% v 5% with gradual progression, 8.6% ONPs, 3.9% normal controls, p=0.07). CONCLUSIONS: Patients with HMSN1a and a stepwise disease progression may have an inflammatory, autoimmune component superimposed on the genetic condition.

Myelin phagocytosis and remyelination of macrophage-enriched central nervous system aggregate cultures.

An increased level of myelin basic protein (MBP) degradation peptide 80-89, representative of myelin breakdown, is detected in myelinating foetal rat brain aggregate cultures supplemented with peritoneal macrophages at a time coinciding with the onset of myelination. During the period of myelination, the proportion of activated macrophages/microglia in the aggregates decreases, accompanied by a reduction in the content of MBP degradation products. During the recovery period following a demyelinating episode, the rate of MBP synthesis in antibody-treated standard aggregates was greater than in their medium controls. However, the rate of MBP accumulation was not as efficient in macrophage-enriched aggregates and was associated with persistently raised MBP peptide levels. Thus, as occurs in multiple sclerosis lesions, attempts at remyelination appear to be counterbalanced by macrophage-mediated demyelination, with the continued presence of degraded myelin rendering a local environment that is not fully conducive to remyelination.

Guillain-Barré syndrome serum and anti-Campylobacter antibody do not exacerbate experimental autoimmune neuritis.

To investigate whether antibodies are pathogenic in Guillain-Barré syndrome (GBS), we injected pre-treatment serum from 11 GBS patients intraperitoneally into rats in which the blood-nerve barrier had been opened by induction of mild adoptive transfer experimental autoimmune neuritis. There was no significant clinical, neurophysiological or pathological difference between rats receiving GBS serum compared with those receiving control serum, except that GBS serum caused minor excess weight loss. Murine monoclonal antibody to Campylobacter jejuni and gangliosides also did not exacerbate disease. This experiment failed to show antibody-mediated disease exacerbation and so does not support an antibody-mediated mechanism in GBS.

Phenotypic and neuropathologic heterogeneity of anti-Hu antibody-related paraneoplastic syndrome presenting with progressive dysautonomia: report of two cases.

The anti-Hu antibody (HuAb) is directed against RNA-associated neuronal proteins and is known to cause paraneoplastic encephalomyelitis/sensory neuronopathy syndrome mostly when associated with small cell lung cancer (SCLC). Paraneoplastic encephalomyelitis/sensory neuronopathy syndrome with concurrent autonomic neuropathy has been reported to occur in paraneoplastic syndromes, although its occurrence concomitant with acute pandysautonomia is less frequent. The authors describe the clinical, neuropathologic, and serologic features of two cases with an anti-Hu-related paraneoplastic syndrome presenting with progressive autonomic neuropathy. Both patients showed features of dysautonomia, including postural dizziness, abdominal pain, and diarrhea, and symptoms of sensory neuropathy. Investigations disclosed severe sensory and autonomic neuropathy and positive HuAb titers. The disease of patient 1 had a very rapid progression, and the patient died of cardiac arrest within 2 months of the onset of symptoms. The autopsy revealed SCLC. In contrast, the disease of patient 2 had a less aggressive course. An extensive tumor search disclosed SCLC only 28 months after onset of symptoms, and the patient died 1 month later of cardiorespiratory arrest. Autopsies in both cases showed inflammation involving the intermediolateral columns and the dorsal root ganglia. These two cases illustrate the association of early dysautonomia with HuAb-related paraneoplastic syndrome and the variations of clinical, neuropathologic, and serologic findings in these types of cases.

Phase variation of a beta-1,3 galactosyltransferase involved in generation of the ganglioside GM1-like lipo-oligosaccharide of Campylobacter jejuni.

Ganglioside mimicry by Campylobacter jejuni lipo-oligosaccharide (LOS) is thought to be a critical factor in the triggering of the Guillain-Barré and Miller-Fisher syndrome neuropathies after C. jejuni infection. The combination of a completed genome sequence and a ganglioside GM1-like LOS structure makes C. jejuni NCTC 11168 a useful model strain for the identification and characterization of the genes involved in the biosynthesis of ganglioside-mimicking LOS. Genome analysis identified a putative LOS biosynthetic cluster and, from this, we describe a putative gene (ORF Cj1139c), which we have termed wlaN, with a significant level of similarity to a number of bacterial glycosyltransferases. Mutation of this gene in C. jejuni NCTC 11168 resulted in a LOS molecule of increased electrophoretic mobility, which also failed to bind cholera toxin. Comparison of LOS structural data from wild type and the mutant strain indicated lack of a terminal beta-1,3-linked galactose residue in the latter. The wlaN gene product was demonstrated unambiguously as a beta-1,3 galactosyltransferase responsible for converting GM2-like LOS structures to GM1-like by in vitro expression. We also show that the presence of an intragenic homopolymeric tract renders the expression of a functional wlaN gene product phase variable, resulting in distinct C. jejuni NCTC 11168 cell populations with alternate GM1 or GM2 ganglioside-mimicking LOS structures. The distribution of wlaN among a number of C. jejuni strains with known LOS structure was determined and, for C. jejuni NCTC 12500, similar wlaN gene phase variation was shown to occur, so that this strain has the potential to synthesize a GM1-like LOS structure as well as the ganglioside GM2-like LOS structure proposed in the literature.

Multiple N-acetyl neuraminic acid synthetase (neuB) genes in Campylobacter jejuni: identification and characterization of the gene involved in sialylation of lipo-oligosaccharide.

N-acetyl neuraminic acid (NANA) is a common constituent of Campylobacter jejuni lipo-oligosaccharide (LOS). Such structures often mimic human gangliosides and are thought to be involved in the triggering of Guillain-Barré syndrome (GBS) and Miller-Fisher syndrome (MFS) following C. jejuni infection. Analysis of the C. jejuni NCTC 11168 genome sequence identified three putative NANA synthetase genes termed neuB1, neuB2 and neuB3. The NANA synthetase activity of all three C. jejuni neuB gene products was confirmed by complementation experiments in an Escherichia coli neuB-deficient strain. Isogenic mutants were created in all three neuB genes, and for one such mutant (neuB1) LOS was shown to have increased mobility. C. jejuni NCTC 11168 wild-type LOS bound cholera toxin, indicating the presence of NANA in a LOS structure mimicking the ganglioside GM1. This property was lost in the neuB1 mutant. Gas chromatography-mass spectrometry and fast atom bombardment-mass spectrometry analysis of LOS from wild-type and the neuB1 mutant strain demonstrated the lack of NANA in the latter. Expression of the neuB1 gene in E. coli confirmed that NeuB1 was capable of in vitro NANA biosynthesis through condensation of N-acetyl-D-mannosamine and phosphoenolpyruvate. Southern analysis demonstrated that the neuB1 gene was confined to strains of C. jejuni with LOS containing a single NANA residue. Mutagenesis of neuB2 and neuB3 did not affect LOS, but neuB3 mutants were aflagellate and non-motile. No phenotype was evident for neuB2 mutants in strain NCTC 11168, but for strain G1 the flagellin protein from the neuB2 mutant showed an apparent reduction in molecular size relative to the wild type. Thus, the neuB genes of C. jejuni appear to be involved in the biosynthesis of at least two distinct surface structures: LOS and flagella.