Clinical correlation with anti-peripheral-nerve myelin antibodies in Guillain-Barré syndrome

Rapid and reversible responses to IVIG in autoimmune neuromuscular diseases suggest mechanisms of action involving competition with functionally important autoantibodies

Intravenous immunoglobulin (IVIG) is widely used in autoimmune neuromuscular diseases whose pathogenesis is undefined. Many different effects of IVIG have been demonstrated in vitro, but few studies actually identify the mechanism(s) most important in vivo. Doses and treatment intervals are generally chosen empirically. Recent studies in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy show that some effects of IVIG are readily reversible and highly dependent on the serum IgG level. This suggests that in some autoantibody-mediated neuromuscular diseases, IVIG directly competes with autoantibodies that reversibly interfere with nerve conduction. Mechanisms of action of IVIG which most likely involve direct competition with autoantibodies include: neutralization of autoantibodies by anti-idiotypes, inhibition of complement deposition, and increasing catabolism of pathologic antibodies by saturating FcRn. Indirect immunomodulatory effects are not as likely to involve competition and may not have the same reversibility and dose-dependency. Pharmacodynamic analyses should be informative regarding most relevant mechanism(s) of action of IVIG as well as the role of autoantibodies in the immunopathogenesis of each disease. Better understanding of the role of autoantibodies and of the target(s) of IVIG could lead to more efficient use of this therapy and better patient outcomes.

Current Therapeutic Options in Severe Guillain-Barre?? Syndrome

The classical form of Guillain-Barré syndrome (GBS) refers to an acute monophasic demyelinating motor and sensory polyneuropathy characterized by symmetric ascending flaccid weakness, along with sensory impairment and, less commonly, autonomic perturbations. Pure motor axonal forms, axonal motor, and sensory forms, as well as pure autonomic forms, have also been identified. A complex immune-mediated process leads to segmental demyelination accompanied with axonal involvement in protracted cases. Establishing strategies of immunomodulation may therefore halt and even reverse the harmful autoimmune insult to peripheral nerves. The present article reviews the current immunomodulatory options in severe GBS. A recent Cochrane meta-analysis of 6 randomized studies showed no significant improvement using corticosteroids, including either oral or intravenous methylprednisolone. Combined methylprednisolone and immunoglobulins shortened the time lapse to regain independent walking. Plasmapheresis (PE) was the first effectively proven method of immunomodulation, followed by intravenous immunoglobulins (IVIG). Both methods are comparable in their beneficial effect and were used either separately or in combination, but PE was more frequently associated with severe adverse effects requiring cessation of therapy, including a bleeding diathesis. In addition, PE is feasible only in major referral centers requiring the appropriate equipment and trained personnel. In addition, younger children may be at risk for bleeding after insertion of wide catheters. Therefore, in cases of severe GBS, IVIG is recommended as the first-line drug using a total empiric dose of 2 g/kg administered over 2 consecutive days, especially in children proven highly effective with negligible adverse effects. In protracted cases, the addition of intravenous corticosteroids to IVIG should be considered, which may shorten the duration to regain independent walking. If such therapy fails, PE should be applied using centrifugal blood separators with 5% albumin as the substitute solution.

Therapeutic apheresis in neurology critical care

Therapeutic apheresis has been widely accepted in the treatment of neurological disorders that are understood to be mediated by humoral and/or cellular immunity. The clinical presumption is that well-established and/or unknown insults cause damage to nerves or their myelin sheaths. The rationale for apheresis treatments for these neurological disorders relates to removal of offending immune (or other) mediators, thus blunting the attack and permitting recovery of nerve and/or myelin. This review will concentrate on the role of therapeutic apheresis, in particular therapeutic plasma exchange, in neurological disorders that may frequently be seen by intensivists.

An approach to evidence-based therapeutic apheresis

This review is derived from a memorial lecture honoring Dr. Francis Morrison, a former President of the American Society For Apheresis (ASFA). The author had numerous professional contacts with Dr. Morrison through ASFA in the early 1990s, having served with him on the Board of Directors and followed him as President, and also came to know him well on a personal level. Professionally, Dr. Morrison stood out as a courtly gentleman with a marvelous baritone voice whose ability to facilitate organization contributed to a growing sense of dignity and purpose in the affairs of the society. On the personal side, however, there wasn't an ounce of pretension in him. He was accessible and down-to-earth; a genuine character with an active and appealing sense of humor. Not surprisingly, he seemed to have a wealth of insight and "common sense," and since the topic of this study is a kind of common sense approach to assessing the effectiveness of therapeutic apheresis, it seems a fitting way to honor his memory.

Outcome of severe Guillain-Barré syndrome in children: comparison between untreated cases versus gamma-globulin therapy

The objective of this study was to assess retrospectively the outcome of children with severe Guillain-Barré syndrome (GBS) treated either with intravenous immunoglobulins (IVIG) versus practically untreated cases by a known beneficial agent. Twenty-three children with severe GBS who became bedridden (i.e., Motor Disability Grading Scale [MDGS] grade of at least 4) were analyzed. Fifteen children were treated with IVIG and eight children comprised the nontreatment group: five on supportive therapy and three treated previously with oral steroids found ineffective in GBS. IVIG was administered at a dosage of 1 g/kg daily for 2 days under constant monitoring, with no adverse effects requiring cessation of therapy. Improvement by 1 grade on the MDGS after IVIG therapy was achieved in the IVIG group after a mean of 10.17 days (median, 8 days), and patients started walking independently after a mean of 30.35 days (median, 20.5 days). Improvement by 1 grade on the MDGS was achieved in the nontreatment group after a mean of 22.3 days (median, 20.3 days), and they started to walk independently after a mean of 113.3 days (median, 100 days). A significant difference could not be delineated between both groups, given the rather small number of children in each group. These results indicate a possible beneficial effect of IVIG in severe childhood-onset GBS compared with the nontreated group of children. The authors therefore recommend using IVIG as the first-line drug in such cases, which warrant further approval after double-blind controlled studies of using different IVIG regimens or combined with plasmapheresis and steroids.

Glial cells as targets for cytotoxic immune mediators

Oligodendrocytes and Schwann cells are the glia principally responsible for the synthesis and maintenance of myelin. Damage may occur to these cells in a number of conditions, but perhaps the most studied are the idiopathic inflammatory demyelinating diseases, multiple sclerosis in the CNS, and Guillain-Barré syndrome and its variants in the peripheral nervous system (PNS). This article explores the effects on these cells of cytotoxic immunological and inflammatory mediators: similarities are revealed, of which perhaps the most important is the sensitivity of both Schwann cells and oligodendrocytes to many such agents. This area of research is, however, characterised and complicated by numerous and often very substantial inter-observer discrepancies. Marked variability in cell culture techniques, and in assays of cell damage and death, provide artifactual explanations for some of this variability; true inter-species differences also contribute. Not the least important conclusion centres on the limited capacity of in vitro studies to reveal disease mechanisms: cell culture findings merely illustrate possibilities which must then be tested ex vivo using human tissue samples affected by the relevant disease.

Can antiglycolipid antibodies present in HIV-infected individuals induce immune demyelination?

Of the eight clinically defined neuropathies associated with HIV infection, there is compelling evidence that acute and chronic inflammatory demyelinating polyneuropathy (IDPN) have an autoimmune pathogenesis. Many non-HIV infected individuals who suffer from sensory-motor nerve dysfunction have autoimmune indicators. The immunopathogenesis of demyelination must involve neuritogenic components in myelin. The various antigens suspected to play a role in HIV-seronegative IDPN include (i) P2 protein; (ii) sulfatide (GalS); (iii) various gangliosides (especially GM1); (iv) galactocerebroside (GalC); and (v) glycoproteins or glycolipids with the carbohydrate epitope glucuronyl-3-sulfate. These glycoproteins or glycolipids may be individually targeted, or an immune attack may be raised against a combination of any of these epitopes. The glycolipids, however, especially GalS, have recently evoked much interest as mediators of immune events underlying both non-HIV and HIV-associated demyelinating neuropathies. The present review outlines the recent research findings of antiglycolipid antibodies present in HIV-infected patients with and without peripheral nerve dysfunction, in an attempt to arrive at some consensus as to whether these antibodies may play a role in the immunopathogenesis of HIV-associated inflammatory demyelinating polyneuropathy.

Terminal complement complexes concomitantly stimulate proliferation and rescue of Schwann cells from apoptosis

The consequences of sublytic terminal complement complex (TCC) assembly on Schwann cell proliferation and apoptosis were examined by using purified complement proteins (C5*-9) or antibody-sensitized Schwann cells in the presence of a serum that was depleted of the seventh component of complement (C7dHS) and reconstituted with purified C7. Stimulation of cultured Schwann cells with antibody plus 10% C7dHS and C7 or C5*-9 induced DNA synthesis over antibody plus 10% C7dHS alone or in Schwann cells in which C5*-9 insertion was inhibited by heat inactivation, respectively. Cell cycle analysis with propidium iodide showed that, at 24 h, viable Schwann cells in defined medium were synchronized in G1/G0 phase. C5*-9 shifted 64% of these cells into S or G2/M phases in a manner similar to beta-neuregulin (beta-NRG), a known Schwann cell mitogen. Furthermore, antibody with 10% C7dHS and C7 or purified C5*-9 induced proliferation of viable Schwann cells. These effects were mediated by signal-transduction pathways involving p44 ERK1 (extracellular-regulated kinase 1), Gi proteins, and protein kinase C. Culturing in defined medium for 24 h resulted in apoptosis of up to 50% of Schwann cells that was prevented by treatment with beta-NRG or TCC. Sublytic C5*-9 significantly inhibited apoptosis 41% by 24 h, as determined by a terminal deoxyuridine triphosphate-biotin nick end labeling assay, and also decreased annexin-V binding at 4 h. Collectively, these data suggest that sublytic TCC, like beta-NRG, is a potent Schwann cell trophic factor that is capable of stimulating mitogenesis and apoptotic rescue. TCC assembly on Schwann cells during inflammatory demyelination of peripheral nerves may promote survival of mature cells to enhance repair and remyelination processes.

Sublytic terminal complement complexes decrease P0 Gene expression in Schwann cells

Complement cascade activation on peripheral nerve myelin can cause myelin destruction. Although terminal complement complexes (TCCs) are transiently detected on Schwann cells (SchCs) during inflammatory neuropathy, SchCs appear resistant to complement-mediated lysis, and little is known about the functional consequences of sublytic TCC deposition on SchCs. We studied the effects of sublytic complement in modulating myelin gene expression at the posttranscriptional and transcriptional levels. Cultured SchCs, stimulated to express protein zero (P0), were treated with sensitizing antibody (Ab) and normal human serum (NHS) complement. P0 mRNA content decreased by 71% during 12 h. In the presence of actinomycin D, P0 mRNA levels declined 50% following incubation with Ab plus 10% NHS over 6 h, compared with control levels, suggesting enhanced P0 mRNA degradation. The decreases, in part, reflected TCC formation because C7 reconstitution of Ab plus C7-depleted human serum (C7dHS) or TCCs assembled from purified components down-regulated P0 mRNA 53 and 55% over that of Ab plus C7dHS or heat-activated components, respectively. Expression of a P0 promoter/luciferase reporter construct transiently transfected into SchCs was reduced 70% by sublytic TCCs at 6 h, demonstrating that P0 gene transcription was also inhibited. c-jun mRNA was up-regulated within 30 min by sublytic TCCs, before the reduction in P0 mRNA expression. Our data suggest that sublytic complement activation on SchCs may contribute to peripheral nerve demyelination by decreasing expression of genes important in myelin formation and compaction.

Pathogenesis of Guillain-Barré syndrome

Recent neurophysiological and pathological studies have led to a reclassification of the diseases that underlie Guillain-Barré syndrome (GBS) into acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor and sensory axonal neuropathy (AMSAN) and acute motor axonal neuropathy (AMAN). The Fisher syndrome of ophthalmoplegia, ataxia and areflexia is the most striking of several related conditions. Significant antecedent events include Campylobacter jejuni (4-66%), cytomegalovirus (5-15%), Epstein-Barr virus (2-10%), and Mycoplasma pneumoniae (1-5%) infections. These infections are not uniquely associated with any clinical subtype but severe axonal degeneration is more common following C. jejuni and severe sensory impairment following cytomegalovirus. Strong evidence supports an important role for antibodies to gangliosides in pathogenesis. In particular antibodies to ganglioside GM1 are present in 14-50% of patients with GBS, and are more common in cases with severe axonal degeneration associated with any subtype. Antibodies to ganglioside GQ1b are very closely associated with Fisher syndrome, its formes frustes and related syndromes. Ganglioside-like epitopes exist in the bacterial wall of C. jejuni. Infection by this and other organisms triggers an antibody response in patients with GBS but not in those with uncomplicated enteritis. The development of GBS is likely to be a consequence of special properties of the infecting organism, since some strains such as Penner 0:19 and 0:41 are particularly associated with GBS but not with enteritis. It is also likely to be a consequence of the immunogenetic background of the patient since few patients develop GBS after infection even with one of these strains. Attempts to match the subtypes of GBS to the fine specificity of anti-ganglioside antibodies and to functional effects in experimental models continue but have not yet fully explained the pathogenesis. T cells are also involved in the pathogenesis of most or perhaps all forms of GBS. T cell responses to any of three myelin proteins, P2, PO and PMP22, are sufficient to induce experimental autoimmune neuritis. Activated T cells are present in the circulation in the acute stage, up-regulate matrix metalloproteinases, cross the blood-nerve barrier and encounter their cognate antigens. Identification of the specificity of these T cell responses is still at a preliminary stage. The invasion of intact myelin sheaths by activated macrophages is difficult to explain according to a purely T cell mediated mechanism. The different patterns of GBS are probably due to the diverse interplay between antibodies and T cells of differing specificities.

Motor root conduction in neuralgic amyotrophy: evidence of proximal conduction block

OBJECTIVE

To determine the presence and role of proximal conduction block in neuralgic amyotrophy.

METHODS

Percutaneous electrical stimulation of cervical roots and brachial plexus was employed in eight patients with neuralgic amyotrophy. Root to Erb's point compound muscle action potential amplitude ratios for abductor digiti minimi, extensor digitorum communis, biceps, and deltoid muscles were compared with results obtained from 10 healthy controls.

RESULTS

Conduction block in the nerve to one muscle was found in three of eight patients (38%) suggesting focal proximal demyelination. Repeat studies showed axonal degeneration, resolution, and persistence of conduction block in these three patients respectively.

CONCLUSION

Focal conduction block plays a significant part in the pathogenesis of neuralgic amyotrophy, which is generally regarded as an axon loss process. Therapeutic intervention should be directed to patients with persistent conduction block, with the aim of eradicating the block and possibly minimising subsequent axon loss.

Poliomyelitis-like syndrome following asthmatic attack (Hopkins' syndrome)--recovery associated with i.v. gamma globulin treatment

A report on a 15-year-old male with a diagnosis of poliomyelitis-like syndrome (Hopkins' syndrome) following an asthmatic attack is presented. The prognosis of Hopkins' syndrome is usually poor and the patients remain with permanent paralysis of the affected limb. The outcome correlates with severity of the initial injury to the anterior horn cell as reflected by abnormal electrophysiologic studies. This is the first case report of treatment with i.v. gamma globulin in Hopkins' syndrome which resulted in a nearly complete recovery.

Circulating transforming growth factor beta 1 (TGF-beta1) in Guillain-Barré syndrome: decreased concentrations in the early course and increase with motor function

OBJECTIVE

To delineate the possible implication of the immunosuppressive cytokine transforming growth factor beta 1 (TGF-beta1) in the pathogenesis of Guillain-Barré syndrome. Guillain-Barré syndrome is a disorder that may implicate cytokines in its pathogenesis. TGF-beta1 is a potent anti-inflammatory cytokine occasionally shown to be regulated in the course of demyelinating disorders.

METHODS

The study measured circulating proinflammatory and anti-inflammatory cytokines from the progressing phase to early recovery in patients with Guillain-Barré syndrome. Plasma concentrations of TNF-alpha, IL-beta1, IL-2, IL-4, IL-6, IL-10, and TGF-beta1 were prospectively evaluated in 15 patients with Guillain-Barré syndrome every three days for the first 15 days after admission to hospital, and in 15 controls with non-inflammatory neurological diseases.

RESULTS

Concentrations of TGF-beta1 in plasma were decreased in 13115 patients (87 %) at day 1, remained low during progression and the plateau of paralysis (days 1-10), and then progressively increased up to control concentrations during early recovery (days 12-15). Concentrations of plasma TGF-beta1 correlated positively with motor function, the lowest values being e found in the most disabled patients. Concentrations of plasma TGF-beta1 were decreased before any treatment, and during treatment by either plasma exchange or intravenous immunoglobulins, plasma exchange being associated with a more pronounced decrease in TGF-beta1 at day 7. Circulating TNF-alpha concentrations were raised, as previously reported, when other cytokines were either randomly increased (IL-2, IL-6), or undetectable (IL-1, IL-4, IL-7, IL-10).

CONCLUSIONS

Down regulation of TGF-beta1 in the early course of Guillain-Barré syndrome could participate in neural inflammation.

The role of complement in disorders of the nervous system

The complement (C) system plays important roles in host defense but activation at inappropriate sites or to an excessive degree can cause host tissue damage. C has been implicated as a factor in the causation or propagation of tissue injury in numerous diseases. The brain is an immunologically isolated site, sheltered from circulating cells and proteins of the immune system; nevertheless, there is a growing body of evidence implicating C in numerous brain diseases. In this brief article we review the evidence suggesting a role for C in diseases of the central and peripheral nervous system and discuss the possible sources of C at these sites. Some brain cells synthesize C and also express specific receptors; some are exquisitely sensitive to the lytic effects of C. The evidence suggests that C synthesis and activation in the brain are important in immune defense at this site, but may also play a role in brain disease.

[Therapeutic plasma exchange 1996]

Therapeutic plasma exchange (TPE) is an extracorporeal blood purification technique to remove large molecular weight substances. Since the late seventies TPE was used in a variety of diseases in which humoral factors may play a part in the pathogenesis. Today, accepted indications only exist for a few entities in defined situations: Anti-glomerular basement membrane antibody mediated disease, TTP/HUS, Guillain-Barré-syndrome, hyperviscosity syndrome, chronic polyneuropathy associated with IgG and IgA gammopathy, chronic inflammatory demyelinating polyneuropathy and myasthenia gravis.

Guillain-Barré syndrome in immunocompromised patients: a report of three patients and review of the literature

Both humoral and cell-mediated autoimmune mechanisms have been implicated in the pathogenesis of Guillain-Barré syndrome (GBS). Therefore, its occurrence in severely immunocompromised patients is not expected. We identified 3 severely immunocompromised patients who developed GBS. Two of the 3 patients had acquired immunodeficiency syndrome with CD4 counts of 5 and 4 cells/mm3, respectively. One post-cardiac transplant patient was taking azathioprine and cyclosporine at the time of onset of GBS. In all 3 patients, immunocompromise was induced by infectious or chemotherapeutic agents which preferentially suppress T-lymphocyte responses. All 3 had severe lymphocytopenia and incomplete recovery. We conclude that GBS can occur in patients with severe t-cell suppression. Although no conclusion regarding prognosis can be drawn from our small group of patients, their incomplete recovery is consistent with the idea that T-cells are important for recovery.

IgM anti-GM1 antibodies in the Guillain-Barré syndrome: a serological predictor of the clinical course

It has been suggested that antibodies against GM1 are involved in the pathogenesis of the Guillain-Barré syndrome (GBS). Recently, we have developed a standardized ELISA assay for anti-GM1 antibodies of IgM type well-suited for longitudinal patient studies. The relationship between serum antibodies against GM1 and Campylobacter jejuni was investigated in patients with GBS and in patients with C. jejuni infection. Patients with a short-lasting anti-GM1 elevation had a fast recovery, whereas patients with slow recovery had a long-lasting anti-GM1 elevation. A linear relationship was found between significant clinical recovery and the time until the anti-GM1 peak was halved (R = 0.9, p < 0.01). The absolute level of anti-GM1 did not predict the length of the recovery nor was the level of anti-GM1 related to the clinical disability at its nadir. Our data indicate that monitoring of the IgM anti-GM1 level can predict clinical recovery in GBS patients.

Immune globulins are effective in severe pediatric Guillain-Barré syndrome

The effect of high-dose intravenous immune globulins was evaluated in an open prospective multicenter study of 26 children with severe Guillain-Barré syndrome. They presented with mild to moderate flaccid weakness of extremities, with cranial nerve involvement (20) and sensory impairment (22). All children rapidly deteriorated in 2-16 days (mean 6) to become bedridden, and 2 children also developed respiratory failure requiring artificial ventilation (Disability Grading Scale 4-5). Immune globulins were then administered at a total dose of 2 gm/kg, on 2 consecutive days, without adverse effects requiring discontinuation of therapy. Marked and rapid improvement was noted in 25 children, who improved by 1 to 2 Disability Grade Scales < or = 2 weeks after the infusion. Twenty were able to walk independently by 1 week, and 1 could be weaned off a ventilator. Eighteen children recovered by 2 weeks. The rest recuperated in a period of four months, including a child who was artificially ventilated for 4 weeks. The uniform rapid improvement and recovery associated with immune globulins contrasts with the slow recovery course in severe natural cases. We conclude that immune globulins are effective and safe in severe childhood-onset Guillain-Barré syndrome and therefore may serve as the initial treatment of choice.

The antibody repertoire in experimental allergic neuritis: evidence for PMP-22 as a novel neuritogen

Experimental allergic neuritis (EAN) is an autoimmune disease that serves as an animal model for the Guillain-Barré syndrome (GBS). In both disorders there is still great uncertainty as to the significance and diversity of autoantibodies involved. We focused on the characterization of serum antibody production in response to various peripheral nervous system (PNS) myelin proteins during the course of actively induced EAN in Lewis rats. These data were compared with EAN induced by adoptive transfer of P2-specific CD4+ T cells (AT-EAN) and with inoculation with complete Freund's adjuvant (CFA) alone. Semiquantitative Western blotting was applied to measure serum IgM and IgG titers against specific myelin proteins, including P2, P0, myelin basic protein (MBP), myelin-associated glycoprotein (MAG) and PMP-22. Considerable differences in the dynamics of antibody titers against individual myelin proteins were observed in active EAN and after inoculation with CFA alone. Our data suggest a pathogenic role of IgM antibodies against HNK adhesion carbohydrate epitope expressing PNS proteins P0, MAG and PMP-22. Among these, PMP-22, a novel candidate neuritogen may be of particular relevance. Thus, we provide evidence for the involvement of antibody-mediated immune response in actively induced EAN and a basis for similar studies on related human disorders such as GBS or other demyelinating neuropathies.

Circulating tumor necrosis factor (TNF)-alpha and soluble TNF-alpha receptors in patients with Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an inflammatory disorder that may implicate proinflammatory cytokines such as TNF-alpha in its pathogenesis. We determined serum levels of TNF-alpha and the specific antagonists sTNF-Rs p55 and p75 in 24 patients with GBS at days 1, 15 and 30 of hospitalization. Patients were in the progression phase of the disease at day 1, and in the recovery phase at day 30. They were classified as able to walk (stage A), confined to bed (B), or under assisted ventilation (C). All patients underwent plasma exchange within day 1-12. At day 1, TNF-alpha levels were elevated in 15/24 patients, and sTNF-Rs were elevated in 21/23. TNF-alpha levels had not decreased at day 15, and dropped at day 30 (p < 0.04), whereas sTNF-R p55 remained elevated at day 15 and day 30. The TNF-alpha/sTNF-Rs ratio, estimating active TNF-alpha unbound to sTNF-Rs, decreased from day 1 to day 30 (p < 0.05). A positive correlation was found between disease severity and sTNF-R serum levels (p < 0.01). In conclusion, elevated circulating sTNF-Rs assesses activation of the TNF-alpha system in almost all patients with GBS and correlates positively with disease severity. Drop of TNF-alpha contrasting with sustained elevation of sTNF-R p55 during recovery suggests that sTNF-R p55 may be important in the fading of the neural inflammatory effect of TNF-alpha in GBS.

Immune attack on the Schwann cell surface in acute inflammatory demyelinating polyneuropathy

The localization, mode of action, and roles of complement in the Guillain-Barre syndrome have been controversial. We used high-resolution immunocytochemistry to localize complement activation products in early stages of the acute inflammatory demyelinating polyneuropathy (AIDP) pattern of Guillain-Barre syndrome. Three AIDP subjects who were autopsied had had symptoms for 3 to 9 days at the time of death. Immunocytochemistry was performed on etched, epoxy resin-embedded sections, and the next thin section was compared by electron microscopy (thick/thin sections). Many fibers had a rim of the complement activation marker C3d and the terminal complement complex neoantigen C5b-9 along the outer surface of the Schwann cells. Ultrastructural analysis of these C3d-positive fibers showed mild vesicular changes of the outermost myelin lamellae. Vesicular degeneration was seen before the invasion of macrophages into the myelin, and was the predominant change in the subject with symptoms for 3 days. C3d staining was not found on myelin membranes. The results suggest that at least some forms of AIDP are complement mediated. We speculate that complement is activated by antibody bound to epitopes on the outer surface of the Schwann cell and that the resulting complement activation initiates the vesiculation of myelin.

Potential role of transforming growth factor-beta 1 in terminating the immune response in patients with Guillain-Barré syndrome

T-cell activation and proinflammatory cytokines seem to be important in promoting the disease activity in Guillain-Barré syndrome (GBS). Transforming growth factor-beta 1 (TGF-beta 1) is a multifunctional peptide with potent immunosuppressive activity, and can therefore be considered a putative disease-limiting cytokine. We determined levels of soluble TGF-beta 1 in the serum of 12 patients with GBS in serial investigations during the course of the disease, in 12 patients with other noninflammatory neurological diseases (OND), and in 12 healthy control subjects. Levels of biologically active and total TGF-beta 1 were significantly increased in patients with GBS compared with patients with OND and healthy controls. During the course of GBS, levels of TGF-beta 1 peaked in the plateau phase before onset of recovery. During the recovery phase levels of TGF-beta 1 decreased but still exceeded significantly the levels in patients with OND and healthy controls. The differences were more marked with biologically active than with total TGF-beta 1. The temporal relationship between increased serum levels of TGF-beta 1 and the end of the progressive phase indicates that TGF-beta 1 has a role in terminating the pathological immune response in GBS. These findings suggest that TGF-beta 1 may be important in recovery from GBS.

Immunopathogenesis and treatment of the Guillain-Barré syndrome--Part I

The etiology of the Guillain-Barré syndrome (GBS) still remains elusive. Recent years have witnessed important advances in the delineation of the mechanisms that may operate to produce nerve damage. Evidence gathered from cell biology, immunology, and immunopathology studies in patients with GBS and animals with experimental autoimmune neuritis (EAN) indicate that GBS results from aberrant immune responses against components of peripheral nerve. Autoreactive T lymphocytes specific for the myelin antigens P0 and P2 and circulating antibodies to these antigens and various glycoproteins and glycolipids have been identified but their pathogenic role remains unclear. The multiplicity of these factors and the involvement of several antigen nonspecific proinflammatory mechanisms suggest that a complex interaction of immune pathways results in nerve damage. Data on disturbed humoral immunity with particular emphasis on glycolipid antibodies and on activation of autoreactive T lymphocytes and macrophages will be reviewed. Possible mechanisms underlying initiation of peripheral nerve-directed immune responses will be discussed with particular emphasis on the recently highlighted association with Campylobacter jejuni infection.

The beta 2-adrenergic agonist terbutaline suppresses experimental allergic neuritis in Lewis rats

Treatment of rats with experimental allergic neuritis with the beta 2-adrenergic agonist terbutaline suppresses clinical symptoms, decreases demyelination and Wallerian degeneration in peripheral nerves and improves electrophysiological parameters. Treatment is highly effective when given from the time of immunization through the acute phase of illness, when given for the first 12 days after immunization and also when given after the onset of the disease.

Immunoglobulins in the treatment of Guillain-Barré syndrome in early childhood

This is a prospective study on the use of immunoglobulins in the treatment of Guillain-Barré syndrome in four children, three of whom were younger than 3 years of age. All of them were unable to walk and were still deteriorating when the treatment was started. Three patients started recovering within 24 hours, and all the patients were fully mobile within 6 weeks after receiving first dose of immunoglobulins. This report shows the efficacy of intravenous immunoglobulins in the treatment of young children presenting with acute Guillain-Barré syndrome.

Manual plasmapheresis in the treatment of Guillain-Barré syndrome

We report on 41 patients with Guillain-Barré Syndrome (GBS) with disability grade 4 and 5 who were treated with manual plasma exchange (PE). Approximately 20-40 ml/kg body weight of plasma was removed with each manual PE; 63% of patients needed one PE, 24% needed two, 10% needed three, and 2% needed four plasma exchanges. Normal saline, human serum albumin (NSA) and fresh frozen plasma were used in varying proportions as replacement solutions. Ninety-one percent of the patients resumed walking with very little assistance ranging from 4 to 56 days with an average of 25 days from the commencement of the first PE. Manual PE in our series was effective and safe as the reported experience of automated apheresis and less volume of plasma was exchanged in our patients undergoing manual PE when compared to those treated in other studies employing automated PE.

Antigalactocerebroside antibody increases demyelination in adoptive transfer experimental allergic neuritis

There is suggestive but inconclusive evidence for a contribution of T cells and antimyelin antibodies to the pathogenesis of the Guillain-Barré polyneuropathy. We have studied the potential synergism of cellular and humoral immunity in the adoptive transfer model of EAN. EAN was induced in Lewis rats by injecting varying doses of P2 peptide (SP26)-sensitized T lymphocytes. Disease severity was dose-dependent. The addition of intravenous GC-AB to a subclinical dose of SP26-sensitized T cells resulted in overt clinical disease and markedly enhanced demyelination. Intravenous injection of antibody alone had no effect. We conclude that activated neuritogenic T cells, while entering into peripheral nerves, alter the blood-nerve barrier, which gives circulating demyelinating antibodies access to the endoneurium. The observations support the concept of a synergistic role of T-cell autoimmunity and humoral responses in the inflammatory demyelination of Lewis rat EAN.

Interleukin-6 levels in the cerebrospinal fluid and serum of patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy

Clinical and experimental findings suggest that humoral factors, such as anti-peripheral nerve antibodies and cytokines, may be implicated in the immunopathogenesis of Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Interleukin-6 (IL-6) is a multifunctional cytokine that promotes immunoglobulin synthesis by B lymphocytes. Increased IL-6 release is associated with autoantibody production in a number of immune-mediated and neoplastic disorders. To investigate the possible involvement of abnormal IL-6 release in inflammatory polyneuropathies, we assayed IL-6 levels in the cerebrospinal fluid (CSF) and serum of 23 patients with acute GBS and seven with CIDP. We also studied 69 patients with other non-inflammatory neurological diseases (NIND), 25 with other inflammatory neurological diseases (IND), four with brain tumors (BT), and 15 normal donors (serum alone) as controls. We found detectable levels of IL-6 in the CSF of 57% of GBS, 43% of CIDP, 60% of IND, 75% of BT, and 4% of NIND. In GBS patients, no correlation was found between CSF IL-6 values and other laboratory or clinical parameters, such as CSF total protein, CSF albumin, CSF IgG, CSF/serum albumin ratio, functional disability score, and time elapsed from disease onset. Serum IL-6 levels were increased in six of 23 (26%) GBS, in one of 39 (3%) NIND, and in one of seven (14%) IND, but in none of the CIDP or BT patients. There was no correlation between serum and CSF IL-6 values, but cytokine levels in GBS sera correlated with time elapsed from clinical onset.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous immunoglobulin in two children with Guillain-Barré syndrome

Two children with Guillain-Barrè syndrome were successfully treated with high-dose intravenous immunoglobulin (IVIG) and no relapses occurred over a 1 year follow up. No side-effects were observed. These data provide further evidence that IVIG may be safely and effectively employed in children with Guillain-Barrè syndrome.

Interleukin-1 and tumor necrosis factor-mediated regulation of C3 gene expression in human astroglioma cells

In this report, we show that in the human astroglioma cell line D54-MG, both interleukin-1 (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) enhance C3 gene expression in a time- and dose-dependent manner. Kinetic analysis demonstrates that after 96 h, C3 mRNA levels increase approximately 30-fold and 20-fold in response to IL-1 beta or TNF-alpha, respectively. C3 protein production increases proportionally, reaching levels 36-fold and 18-fold higher than untreated controls upon exposure to IL-1 beta or TNF-alpha, respectively. D54-MG cells require a minimal 1 h exposure to IL-1 beta in order to enhance C3 gene expression significantly, while 4 to 8 h are required for TNF-alpha. Simultaneous treatment of D54-MG cells with IL-1 beta and interferon-gamma (IFN-gamma) resulted in an additive increase in both C3 mRNA and protein expression, a finding not seen with the combination of TNF-alpha and IFN-gamma. Primary rat astrocytes also express increased C3 mRNA levels after 48 h in response to IL-1 beta (5.3-fold increase) and TNF-alpha (7-fold increase), while an additive effect was observed upon simultaneous treatment with both IL-1 beta and IFN-gamma. In the central nervous system (CNS), endogenous complement and cytokine production by astrocytes, and enhancement by IFN-gamma, a product of activated T cells often seen in the CNS in neural autoimmune disease, may contribute to the pathogenesis of inflammatory demyelinating diseases such as multiple sclerosis.

Autoantibodies to phospholipids and brain extract in patients with the Guillain-Barre syndrome: cross-reactive or pathogenic?

Guillain-Barre syndrome (GBS) is a transient neurological disorder characterized by an inflammatory demyelination of peripheral nerves. Although the pathogenesis of GBS has not been elucidated, there is increasing evidence pointing to an autoimmune etiology. We have studied the reactivity of GBS sera with various phospholipids which are known to be important constituents of myelin, and serve as autoantigens in other autoimmune conditions. Sixteen Guillain-Barre syndrome (GBS) sera were studied for the presence of autoantibodies to ssDNA, dsDNA, cardiolipin (CL), phosphatidyl-ethanolamine (PE), phosphatidyl-choline (PC), phosphatidyl-serine (PS), and brain extract. Six of the 16 GBS sera had autoantibodies to one or more of the antigens studied. Three of the sera contained autoantibodies to brain extract (p < 0.05), two of the sera had autoantibodies to dsDNA, ssDNA, CL and PE, and one serum had autoantibodies to PC, and PS. As expected a significant proportion of the lupus sera contained autoantibodies to ssDNA and dsDNA, while the frequency of autoantibodies to different phospholipids was significantly high in sera of patients with systemic lupus erythematosus (SLE) and cerebritis. Absorption of GBS sera with cardiolipin, phosphatidyl-choline, or brain extract inhibited the binding of the sera to cardiolipin. Our results demonstrate that some GBS patients produce autoantibodies to various phospholipid and nuclear antigens. However, these autoantibodies are probably produced as a result of the myelin damage rather than cause the demyelination.

Serum and CSF anti-GM1 antibodies in patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy

High titers of antibodies directed against gangliosides, especially GM1, are found in the serum of patients with a variety of polyneuropathies, including those of the inflammatory type. We assayed anti-GM1 IgG and IgM levels in the serum and cerebrospinal fluid (CSF) of 23 patients with Guillain-Barré syndrome (GBS) and 10 with chronic inflammatory demyelinating polyneuropathy (CIDP) to investigate whether this immune response may also be localized within the intrathecal compartment and correlate with clinical parameters such as time interval since disease onset, disability score, preceding infectious episodes, and GM1 therapy. When compared to the control group, anti-GM1 IgG was increased in the serum of 39% of GBS and 10% of CIDP patients, whereas anti-GM1 IgM was elevated in 17% of GBS and none of the CIDP patients. In both patient groups, however, anti-GM1 antibody levels were more frequently elevated in CSF than paired sera: they belonged to the IgG class in 48% of GBS and 50% of CIDP patients, and to the IgM class in 48% of GBS and 55% of CIDP patients. In the GBS group, anti-GM1 IgM serum levels inversely correlated with time elapsed between sample collection and onset of disease (P < 0.05), whereas serum anti-GM1 IgG levels positively correlated with the loss of functional ability (P < 0.005). Increased anti-GM1 antibodies in GBS serum were not associated with clinical or serological evidence of infectious antecedents nor with previous GM1 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Guillain-Barré sera containing antibodies against glycolipids in cultures of rat Schwann cells and sensory neurons

Serum samples from 52 patients with the acute Guillain-Barré syndrome (GBS), 19 patients with other neurological disorders, and 18 healthy volunteers were tested for cytotoxicity in cultures of rat Schwann cells and dorsal root ganglion neurons. The samples were also examined by enzyme-linked immunosorbent assay for IgG and IgM antibodies against various acidic and neutral glycolipids. Samples from 16 of the 52 (31%) acute GBS patients and from 1 of the 6 patients with chronic inflammatory demyelinating polyneuropathy produced myelin breakdown in culture. Although 10 of the 16 cytotoxic acute GBS serum samples contained anti-glycolipid immunoglobulins, there was no correlation in individual samples between cytotoxic activity and the presence of antibodies against specific glycolipids. While our results do not exclude a role for anti-glycolipid antibodies in the pathogenesis of the acute GBS, the cytotoxic effects of acute GBS serum in cultures of Schwann cells and sensory neurons are probably not due to these antibodies alone.

Ganglioside antibodies: a lack of diagnostic specificity and clinical utility?

Serum IgG and IgM antibodies to gangliosides GM1, GM2, GM3, AGM1, GD1a, GD1b and GT1b were determined in 210 patients with different degenerative and inflammatory disorders including motor neuron diseases, peripheral radiculopathies and neuropathies, multiple sclerosis and neuroborreliosis. No single disorder was associated specifically with ganglioside antibodies. No characteristic patterns of ganglioside antibodies were observed in any disease category. However, 32% of all patients had pathological antibody titres to at least one ganglioside. Four patients had pathological IgG and IgM titres for all gangliosides evaluated. They suffered from systemic lupus erythematosus [2], neuroborreliosis and schizophrenia, respectively. The results of this study indicate that the introduction of ganglioside antibody determination as a differential diagnostic test in clinical neurology is only helpful in a few patients with typical lower motor neuron syndromes.

[Plasmapheresis in neurology. Critical analysis of indications and protocols]

Therapeutic plasmapheresis (plasma exchange) in neurology is a matter of discussion. We review the main articles on clinical trials, both controlled and uncontrolled, trying to establish the efficacy and safety of the procedure. Humoral aspects involved in the genesis of the disorder play an important role for its indication in the present time. In myasthenia gravis indications for plasmapheresis are established: in the preparation for thymectomy, in patients with respiratory insufficiency and requiring respiratory prosthesis, after long immunosuppression therapy with rebound effect, when all other forms of therapy failed, and in neonatal myasthenia gravis with special technics. We discuss the indication of plasmapheresis in Guillain-Barré syndrome, multiple sclerosis, chronic inflammatory demyelinating polyneuromyelopathy, HTLV-1 myelopathy, HIV peripheral neuropathy and myelopathy, paraproteinemias, polymyositis, and dermatomyositis. Indications for other diseases are mentioned. Reference is made to the results we observed in 31 cases followed consecutively at Hospital dos Servidores, Rio de Janeiro, from June 1984 to June 1990. In our series 26 were myasthenic patients, 4 patients presented Guillain-Barré syndrome, and 1 multiple sclerosis. Therapeutic plasmapheresis protocols suggested by us are summarized.

The Guillain-Barré syndrome: no longer a simple concept

Acute inflammatory demyelinating polyneuropathy or the Guillain-Barré syndrome (GBS) has come to be accepted as a clinical entity, although the boundary between it and chronic inflammatory demyelinating polyneuropathy has given rise to discussion. Recent observations have suggested that the GBS may represent the consequence of more than one pathogenetic mechanism. In most cases the salient pathological change is demyelination. In some this may be mediated predominantly by lymphocytes; in others, where the demyelination is produced primarily by macrophages, the process may be antibody-mediated. Both electrophysiological and pathological evidence indicates that occasional patients with the GBS show extensive axonal degeneration. Although this could represent a "bystander effect" secondary to inflammatory infiltration, at times it may reflect a direct attack on axons. Elucidation of the nature of the pathogenetic mechanisms is essential before rational therapy can be devised.