Pediatric acute flaccid myelitis: Evaluation of diagnostic criteria and differentiation from other causes of acute flaccid paralysis.

BACKGROUND: Acute flaccid paralysis (AFP) is characterized by rapidly progressive limb weakness with low muscle tone. It has a broad differential diagnosis, which includes acute flaccid myelitis (AFM), a rare polio-like condition that mainly affects young children. Differentiation between AFM and other causes of AFP may be difficult, particularly at onset of disease. Here, we evaluate the diagnostic criteria for AFM and compare AFM to other causes of acute weakness in children, aiming to identify differentiating clinical and diagnostic features. METHODS: The diagnostic criteria for AFM were applied to a cohort of children with acute onset of limb weakness. An initial classification based on positive diagnostic criteria was compared to the final classification, based on application of features suggestive for an alternative diagnosis and discussion with expert neurologists. Cases classified as definite, probable, or possible AFM or uncertain, were compared to cases with an alternative diagnosis. RESULTS: Of 141 patients, seven out of nine patients initially classified as definite AFM, retained this label after further classification. For probable AFM, this was 3/11, for possible AFM 3/14 and for uncertain 11/43. Patients initially classified as probable or possible AFM were most commonly diagnosed with transverse myelitis (16/25). If the initial classification was uncertain, Guillain-Barré syndrome was the most common diagnosis (31/43). Clinical and diagnostic features not included in the diagnostic criteria, were often used for the final classification. CONCLUSION: The current diagnostic criteria for AFM usually perform well, but additional features are sometimes required to distinguish AFM from other conditions.

Differences in IgG autoantibody Fab glycosylation across autoimmune diseases.

BACKGROUND: Increased prevalence of autoantibody Fab glycosylation has been demonstrated for several autoimmune diseases. OBJECTIVES: To study whether elevated Fab glycosylation is a common feature of autoimmunity, this study investigated Fab glycosylation levels on serum IgG and its subclasses for autoantibodies associated with a range of different B cell-mediated autoimmune diseases, including rheumatoid arthritis, myasthenia gravis subtypes, pemphigus vulgaris, antineutrophil cytoplasmic antibody-associated vasculitis, systemic lupus erythematosus, anti-glomerular basement membrane glomerulonephritis, thrombotic thrombocytopenic purpura, and Guillain-Barré syndrome. METHODS: The level of Fab glycosylated IgG antibodies was assessed by lectin affinity chromatography and autoantigen-specific immunoassays. RESULTS: In 6 of 10 autoantibody responses, in 5 of 8 diseases, the investigators found increased levels of Fab glycosylation on IgG autoantibodies that varied from 86% in rheumatoid arthritis to 26% in systemic lupus erythematosus. Elevated autoantibody Fab glycosylation was not restricted to IgG4, which is known to be prone to Fab glycosylation, but was also present in IgG1. When autoimmune diseases with a chronic disease course were compared with more acute autoimmune illnesses, increased Fab glycosylation was restricted to the chronic diseases. As a proxy for chronic autoantigen exposure, the investigators determined Fab glycosylation levels on antibodies to common latent herpes viruses, as well as to glycoprotein 120 in individuals who are chronically HIV-1-infected. Immunity to these viral antigens was not associated with increased Fab glycosylation levels, indicating that chronic antigen-stimulation as such does not lead to increased Fab glycosylation levels. CONCLUSIONS: These data indicate that in chronic but not acute B cell-mediated autoimmune diseases, disease-specific autoantibodies are enriched for Fab glycans.

Guía basada en la evidencia. Diagnóstico y manejo del síndrome de Guillain-Barré en diez pasos / Evidence based guidelines. Diagnosis and management of Guillain-Barré syndrome in ten steps

Resumen El síndrome de Guillain-Barré (SGB) es una enfermedad inmunológica del nervio periférico y las raíces nerviosas, poco frecuente, potencialmente mortal y que suele desencadenarse por infecciones. La incidencia del SGB puede aumentar durante el brote de enfermedades infecciosas, tal como se observó en las epidemias del virus Zika en la Polinesia Francesa en 2013 y en América Latina en 2015. El diagnóstico y el manejo clínico del SGB pueden ser complicados ya que su presentación y el curso de la enfermedad son heterogéneos, y actualmente no se cuenta con guías clínicas internacionales. Para respaldar a los médicos, especialmente en el contexto de un brote de una enfermedad infecciosa, hemos desarrollado una guía clínica aplicable en todo el mundo para el diagnóstico y el tratamiento del SGB. La guía se basa en literatura actualizada y el consenso de expertos, y tiene una estructura de diez pasos para facilitar su uso en la práctica clínica. Inicialmente, brindamos una introducción a los criterios de diagnóstico, variantes clínicas y diagnósticos diferenciales del SGB. Los diez pasos luego abordan el reconocimiento y el diagnóstico temprano del SGB, la admisión a la unidad de cuidados intensivos, indicación y selección de tratamiento, seguimiento y tratamiento de la progresión de la enfermedad, predicción del curso clínico, resultados y tratamiento de complicaciones y secuelas.

Abstract Guillain-Barré syndrome (GBS) is a rare, but potentially fatal, immune-mediated disease of the peripheral nerves and nerve roots that is usually triggered by infections. The incidence of GBS can therefore increase during outbreaks of infectious diseases, as was seen during the Zika virus epidemics in 2013 in French Polynesia and in 2015 in Latin America. Diagnosis and management of GBS can be complicated as its clinical presentation and disease course are heterogeneous, and no international clinical guidelines are currently available. To support clinicians, especially in the context of an outbreak, we have developed a globally applicable guideline for the diagnosis and management of GBS. The guideline is based on current literature and expert consensus, and has a ten-step structure to facilitate its use in clinical practice. We first provide an introduction to the diag nostic criteria, clinical variants and differential diagnoses of GBS. The ten steps then cover early recognition and diagnosis of GBS, admission to the intensive care unit, treatment indication and selection, monitoring and treatment of disease progression, prediction of clinical course and outcome, and management of complications and sequelae.

Antecedent infections in Guillain-Barré syndrome in endemic areas of arbovirus transmission: A multinational case-control study.

Half of the world's population is at risk of arthropod-borne virus (arbovirus) infections. Several arbovirus infections have been associated with Guillain-Barré syndrome (GBS). We investigated whether arboviruses are driving GBS beyond epidemic phases of transmission and studied the antibody response to glycolipids. The protocol of the International Guillain-Barré syndrome Outcome Study (IGOS), an observational prospective cohort study, was adapted to a case-control design. Serum samples were tested for a recent infection with Zika virus (ZIKV), dengue virus (DENV), chikungunya (CHIKV) virus, hepatitis E virus, Epstein-Barr virus (EBV), cytomegalovirus (CMV), Campylobacter jejuni, and Mycoplasma pneumoniae, and for antibodies to glycolipids. Forty-nine patients were included from Brazil (63%), Argentina (14%), and Malaysia (22%). Evidence of a recent infection was found in 27/49 (55%) patients: C jejuni (n = 15, 31%), M pneumoniae (n = 5, 10%), CHIKV (n = 2, 4%), EBV (n = 1, 2%), C jejuni and M pneumoniae (n = 2, 4%), CMV and DENV (n = 1, 2%), and C jejuni and DENV (n = 1, 2%). In 22 patients, 35 paired controls were collected. Odds ratio for recent infections did not significantly differ between cases and controls. No typical anti-ganglioside antibody binding was associated with recent arbovirus infection. We conclude that arbovirus infections occur in GBS patients outside of epidemic viral transmission, although not significantly more than in controls. Broad infection and anti-ganglioside antibody serology are important to establish the most likely pathogenic trigger in GBS patients. Larger studies are necessary to determine the association between arboviruses and GBS.

IVIg-induced plasmablasts in patients with Guillain-Barré syndrome.

Objective: The Guillain-Barré syndrome (GBS) is an acute, immune-mediated disease of peripheral nerves. Plasmablasts and plasma cells play a central role in GBS by producing neurotoxic antibodies. The standard treatment for GBS is high-dose intravenous immunoglobulins (IVIg), however the working mechanism is unknown and the response to treatment is highly variable. We aimed to determine whether IVIg changes the frequency of B-cell subsets in patients with GBS. Methods: Peripheral blood mononuclear cells were isolated from 67 patients with GBS before and/or 1, 2, 4, and 12 weeks after treatment with high-dose IVIg. B-cell subset frequencies were determined by flow cytometry and related to serum immunoglobulin levels. Immunoglobulin transcripts before and after IVIg treatment were examined by next-generation sequencing. Antiglycolipid antibodies were determined by ELISA. Results: Patients treated with IVIg demonstrated a strong increase in plasmablasts, which peaked 1 week after treatment. Flow cytometry identified a relative increase in IgG2 plasmablasts posttreatment. Within IGG sequences, dominant clones were identified which were also IGG2 and had different immunoglobulin sequences compared to pretreatment samples. High plasmablast frequencies after treatment correlated with an increase in serum IgG and IgM, suggesting endogenous production. Patients with a high number of plasmablasts started to improve earlier (P = 0.015) and were treated with a higher dose of IVIg. Interpretation: High-dose IVIg treatment alters the distribution of B-cell subsets in the peripheral blood of GBS patients, suggesting de novo (oligo-)clonal B-cell activation. Very high numbers of plasmablasts after IVIg therapy may be a potential biomarker for fast clinical recovery.

Clinical relevance of serum antibodies to GD1b in immune-mediated neuropathies.

Antibodies to the ganglioside GD1b have been reported in various forms of immune-mediated neuropathy, but their clinical relevance for diagnosis and prognosis is unknown. We investigated the prevalence of anti-GD1b antibodies in acute and chronic immune-mediated neuropathies, and the clinical presentation and outcome in Guillain-Barré syndrome (GBS) and Miller Fisher-GBS overlap syndrome (MF-GBS). Anti-GD1b, anti-GM1 and anti-GQ1b antibodies were tested in serum of patients with GBS (N = 165), Miller Fisher syndrome (N = 10), MF-GBS (N = 28), monoclonal gammopathy of unknown significance neuropathy (MGUS; N = 101), chronic inflammatory demyelinating polyneuropathy (N = 29), paraneoplastic syndrome with anti-Hu-associated neuropathy (PNS; N = 11), other auto-immune diseases (AID; N = 60), and healthy controls (HC; N = 60). All samples were tested by enzyme-linked immunosorbent assay according to the Inflammatory Neuropathy Cause and Treatment protocol. IgM anti-GD1b antibodies were found in GBS (N = 4; 2.4%), MGUS (N = 3; 3.0%), and PNS patients (N = 1; 9.1%). IgG anti-GD1b antibodies were found in GBS (N = 20; 12.1%) and MF-GBS (N = 4; 14.3%) patients, but not in the AID and HC group. In the combined group of MF-GBS and GBS patients ((MF-)GBS), 14/36 (38.9%) patients with IgG anti-GD1b antibodies also had IgG anti-GM1 antibodies, and IgG anti-GD1b and IgG anti-GQ1b antibodies were found in 3/29 (10.3%) patients. Patients with (MF-)GBS and anti-GD1b without anti-GM1 antibodies did not differ regarding sensory disturbances or disease severity but recovered faster regarding the ability to walk independently compared with patients without anti-GD1b antibodies (P = 0.031) and with patients with both anti-GD1b and anti-GM1 antibodies (P = 0.034). In conclusion, testing for anti-GD1b antibodies may identify a specific group of immune-mediated neuropathies and (MF-)GBS patients with only anti-GD1b antibodies tend to recover faster.

Hepatitis E Virus Infects Neurons and Brains.

Hepatitis E virus (HEV), as a hepatotropic virus, is supposed to exclusively infect the liver and only cause hepatitis. However, a broad range of extrahepatic manifestations (in particular, idiopathic neurological disorders) have been recently reported in association with its infection. In this study, we have demonstrated that various human neural cell lines (embryonic stem cell-derived neural lineage cells) induced pluripotent stem cell-derived human neurons and primary mouse neurons are highly susceptible to HEV infection. Treatment with interferon-α or ribavirin, the off-label antiviral drugs for chronic hepatitis E, exerted potent antiviral activities against HEV infection in neural cells. More importantly, in mice and monkey peripherally inoculated with HEV particles, viral RNA and protein were detected in brain tissues. Finally, patients with HEV-associated neurological disorders shed the virus into cerebrospinal fluid, indicating a direct infection of their nervous system. Thus, HEV is neurotropic in vitro, and in mice, monkeys, and possibly humans. These results challenge the dogma of HEV as a pure hepatotropic virus and suggest that HEV infection should be considered in the differential diagnosis of idiopathic neurological disorders.

Hepatitis E virus: Infection beyond the liver?

Hepatitis E virus (HEV) infections are not limited to the liver but may also affect other organs. Several diseases, including Guillain-Barré syndrome, neuralgic amyotrophy, glomerulonephritis, cryoglobulinemia, pancreatitis, lymphoma, thrombopenia, meningitis, thyroiditis and myocarditis have been observed in the context of hepatitis E. To date, the definite pathophysiological links between HEV and extrahepatic manifestations are not yet established. However, it is suggested that HEV infection might be causative based on serological studies, case series, in vitro data and animal models. In particular, neuronal and renal diseases as well as pancreatitis seem to be caused by HEV, while a causative relationship between HEV and other diseases is more doubtful. Either direct cytopathic tissue damage by extrahepatic replication, or immunological processes induced by an overwhelming host immune response, are possible origins of HEV-associated extrahepatic manifestations. Hepatologists should be aware of the possibility that acute or chronically HEV-infected patients could develop extrahepatic manifestations. Neurologists, nephrologists, rheumatologists and other groups of physicians should consider HEV infection as a potential differential diagnosis when observing one of the diseases described in this review. Ribavirin and steroids have been used in small groups of patients with extrahepatic manifestations of HEV, but the efficacy of these drugs still needs to be verified by large, multicenter studies. This article comprehensively reviews the published literature regarding HEV and extrahepatic manifestations. We discuss the probability of specific extrahepatic diseases being caused by previous or ongoing HEV infection, and summarize the published knowledge about antiviral treatment in extrahepatic disorders.

Skewed Fc glycosylation profiles of anti-proteinase 3 immunoglobulin G1 autoantibodies from granulomatosis with polyangiitis patients show low levels of bisection, galactosylation, and sialylation.

Granulomatosis with polyangiitis (GPA) is associated with circulating immunoglobulin (Ig) G anti-proteinase 3 specific (anti-PR3) anti-neutrophil cytoplasm antibodies (ANCA), which activate cytokine primed neutrophils via Fcgamma receptors. ANCA are class switched IgG antibodies implying T cell help in their production. Glycosylation of IgG Fc, under the control of T cell cytokines, determines the interaction between IgG and its receptors. Previous studies have reported aberrant glycosylation of Ig Fc in GPA patients. We investigated whether aberrant Fc glycosylation was present on anti-PR3 ANCA as well as whole IgG subclass preparations compared to healthy controls and whether this correlated with Birmingham vasculitis activity scores (BVAS), serum cytokines, and time to remission. Here, IgG Fc glycosylation of GPA patients and controls and anti-PR3 ANCA Fc glycosylation were determined by mass spectrometry of glycopeptides. IgG1 and IgG2 subclasses from GPA patients showed reduced galactosylation, sialylation, and bisection compared to healthy controls. Anti-PR3 IgG1 ANCA Fc galactosylation, sialylation, and bisection were reduced compared to total IgG1 in GPA. Galactosylation of anti-PR3 ANCA Fc correlated with inflammatory cytokines and time to remission but not BVAS. Bisection of anti-PR3 ANCA Fc correlated with BVAS. Total IgG1 and anti-PR3 IgG1 Fc galactosylation were weakly correlated, while bisection of IgG1 and anti-PR3 showed no correlation. Our data indicate that aberrant ANCA galactosylation may be driven in an antigen-specific manner.

Sialylation of Campylobacter jejuni endotoxin promotes dendritic cell-mediated B cell responses through CD14-dependent production of IFN-ß and TNF-α.

Campylobacter jejuni is the most common bacterial cause of human gastroenteritis and often precedes development of Guillain-Barré syndrome (GBS), a life-threatening paralytic disease. The incorporation of the carbohydrate sialic acid into C. jejuni lipooligosaccharides (LOS) is associated with increased severity of gastroenteritis and with induction of GBS; however, the underlying mechanisms remain completely unknown. In this study, we demonstrate that sialic acids in C. jejuni endotoxin enhance the rapid production of IFN-ß and TNF-α by human dendritic cells (DCs). Using neutralizing Abs and receptors it was shown that these DC-derived cytokines promote the proliferation of human mucosal B cells in a T cell-independent manner. The production of both IFN-ß and TNF-α by DCs in response to LOS requires CD14, and the amplified response of DCs to sialylated C. jejuni LOS is CD14 dependent. Together, these results indicate that sialylation of C. jejuni LOS increases DC activation and promotes subsequent B cell responses through CD14-driven production of IFN-ß and TNF-α. This enhanced DC/B cell response may explain the increased pathogenicity of sialylated C. jejuni and may be key to the initiation of B cell-mediated autoimmunity in GBS.

Enhanced, sialoadhesin-dependent uptake of Guillain-Barre syndrome-associated Campylobacter jejuni strains by human macrophages.

Molecular mimicry between Campylobacter jejuni sialylated lipooligosaccharides (LOS) and human nerve gangliosides can trigger the production of cross-reactive antibodies which induce Guillain-Barré syndrome (GBS). To better understand the immune events leading to GBS, it is essential to know how sialylated LOS are recognized by the immune system. Here, we show that GBS-associated C. jejuni strains bind to human sialoadhesin (hSn), a conserved, mainly macrophage-restricted I-type lectin. Using hSn-transduced THP-1 cells, we observed that C. jejuni strains with α(2,3)-sialylated LOS, including strains expressing GM1a- and GD1a-like epitopes, bind to hSn. This observation is of importance, as these epitopes are frequently the targets of the cross-reactive antibodies detected in GBS patients. Interestingly, the Sn binding domains were not constitutively exposed on the surface of C. jejuni. Heat inactivation and the environmental conditions which food-borne C. jejuni encounters during its passage through the intestinal tract, such as low pH and contact with bile constituents, exposed LOS and facilitated Sn binding. Sn binding enhanced bacterial uptake and increased the production of interleukin-6 (IL-6) by primary human Sn-expressing monocyte-derived macrophages compared to control conditions, where Sn was blocked using neutralizing antibodies or when nonsialylated C. jejuni was used. Sn-mediated uptake has been reported to enhance humoral immune responses. As C. jejuni strains expressing ganglioside mimics GD1a and GM1a are closely associated with GBS, Sn binding may be a determining event in the production of cross-reactive antibodies and the development of GBS.

Sialylation of Campylobacter jejuni lipo-oligosaccharides: impact on phagocytosis and cytokine production in mice.

BACKGROUND: Guillain-Barré syndrome (GBS) is a post-infectious polyradiculoneuropathy, frequently associated with antecedent Campylobacter jejuni (C. jejuni) infection. The presence of sialic acid on C. jejuni lipo-oligosaccharide (LOS) is considered a risk factor for development of GBS as it crucially determines the structural homology between LOS and gangliosides, explaining the induction of cross-reactive neurotoxic antibodies. Sialylated C. jejuni are recognised by TLR4 and sialoadhesin; however, the functional implications of these interactions in vivo are unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this study we investigated the effects of bacterial sialylation on phagocytosis and cytokine secretion by mouse myeloid cells in vitro and in vivo. Using fluorescently labelled GM1a/GD1a ganglioside-mimicking C. jejuni strains and corresponding (Cst-II-mutant) control strains lacking sialic acid, we show that sialylated C. jejuni was more efficiently phagocytosed in vitro by BM-MΦ, but not by BM-DC. In addition, LOS sialylation increased the production of IL-10, IL-6 and IFN-ß by both BM-MΦ and BM-DC. Subsequent in vivo experiments revealed that sialylation augmented the deposition of fluorescent bacteria in splenic DC, but not macrophages. In addition, sialylation significantly amplified the production of type I interferons, which was independent of pDC. CONCLUSIONS/SIGNIFICANCE: These results identify novel immune stimulatory effects of C. jejuni sialylation, which may be important in inducing cross-reactive humoral responses that cause GBS.

Campylobacter jejuni lipooligosaccharides modulate dendritic cell-mediated T cell polarization in a sialic acid linkage-dependent manner.

Carbohydrate mimicry between Campylobacter jejuni lipooligosaccharides (LOS) and host neural gangliosides plays a crucial role in the pathogenesis of Guillain-Barré syndrome (GBS). Campylobacter jejuni LOS may mimic various gangliosides, which affects the immunogenicity and the type of neurological deficits in GBS patients. Previous studies have shown the interaction of LOS with sialic acid-specific siglec receptors, although the functional consequences remain unknown. Cells that express high levels of siglecs include dendritic cells (DCs), which are crucial for initiation and differentiation of immune responses. We confirm that α2,3-sialylated GD1a/GM1a mimic and α2,8-sialylated GD1c mimic LOS structures interact with recombinant Sn and siglec-7, respectively. Although the linkage of the terminal sialic acid of LOS did not regulate expression of DC maturation markers, it displayed clear opposite expression levels of interleukin-12 (IL-12) and OX40L, molecules involved in DC-mediated Th cell differentiation. Accordingly, targeting DC-expressed siglec-7 with α2,8-linked sialylated LOS resulted in Th1 responses, whereas Th2 responses were induced by targeting with LOS containing α2,3-linked sialic acid. Thus, our data demonstrate for the first time that depending on the sialylated composition of Campylobacter jejuni LOS, specific Th differentiation programs are initiated, possibly through targeting of distinct DC-expressed siglecs.

Guillain-Barré syndrome subtypes related to Campylobacter infection.

BACKGROUND: In Guillain-Barré syndrome (GBS), the diversity in electrophysiological subtypes is unexplained but may be determined by geographical factors and preceding infections. Acute motor axonal neuropathy (AMAN) is a frequent GBS variant in Japan and one study proposed that in Japan, Campylobacter jejuni infections exclusively elicit AMAN. In The Netherlands C jejuni is the predominant type of preceding infection yet AMAN is rare. This may indicate that not all Dutch GBS patients with C jejuni infections have AMAN. OBJECTIVE: To determine if GBS patients with a preceding C jejuni infection in The Netherlands exclusively have AMAN. METHODS: Retrospective analysis of preceding infections in relation to serial electrophysiology and clinical data from 123 GBS patients. C jejuni related cases were defined as having preceding diarrhoea and positive C jejuni serology. Electrophysiological characteristics in C jejuni related cases were compared with those in viral related GBS patients. In addition, eight GBS patients from another cohort with positive stool cultures for C jejuni were analysed. RESULTS: 17 (14%) of 123 patients had C jejuni related GBS. C jejuni patients had lower motor and higher sensory action potentials compared with viral related cases. Nine (53%) C jejuni patients had either AMAN or inexcitable nerves. However, three (18%) patients fulfilled the criteria for acute inflammatory demyelinating polyneuropathy (AIDP). Also, two (25%) of eight additional patients with a C jejuni positive stool sample had AIDP. CONCLUSION: In The Netherlands, C jejuni infections are strongly, but not exclusively, associated with axonal GBS. Some patients with these infections fulfil current criteria for demyelination.

TLR4-mediated sensing of Campylobacter jejuni by dendritic cells is determined by sialylation.

In Guillain-Barré syndrome (GBS), ganglioside mimicry of Campylobacter jejuni lipo-oligosaccharide (LOS) drives the production of cross-reactive Abs to peripheral nerve gangliosides. We determined whether sialic acid residues in C. jejuni LOS modulate dendritic cell (DC) activation and subsequent B cell proliferation as a possible mechanism for the aberrant humoral immune response in GBS. Highly purified sialylated LOS of C. jejuni isolates from three GBS patients induced human DC maturation and secretion of inflammatory cytokines that were inhibited by anti-TLR4 neutralizing Abs. The extent of TLR4 signaling and DC activation was greater with LOS of the wild type isolates than with nonsialylated LOS of the corresponding sialyltransferase gene knockout (cst-II mutant) strains, indicating that sialylation boosts the DC response to C. jejuni LOS. Supernatants of LOS-activated DCs induced B cell proliferation after cross-linking of surface Igs in the absence of T cells. Lower B cell proliferation indices were found with DC supernatants after DC stimulation with cst-II mutant or neuraminidase desialylated LOS. This study showed that sialylation of C. jejuni LOS enhances human DC activation and subsequent B cell proliferation, which may contribute to the development of cross-reactive anti-ganglioside Abs found in GBS patients following C. jejuni infection.

Genetic polymorphisms of macrophage-mediators in Guillain-Barré syndrome.

Macrophages infiltrate peripheral nerves and may contribute to neural damage in the Guillain-Barré syndrome (GBS). We determined whether single nucleotide polymorphisms (SNP) in genes encoding macrophage-mediators are related to the susceptibility and severity of GBS. The frequencies of SNP in the TNFA, MMP9, IL10, and NOS2a genes did not differ between 263 GBS patients and 210 healthy subjects. The MMP9 C(-1562)T and TNFA C(-863)A SNP were associated with severe weakness and poor outcome, indicating that these SNP may be one of the factors predisposing to a severe form of GBS.

Immunoglobulin gene analysis in polyneuropathy associated with IgM monoclonal gammopathy.

Antineural antibody activity is the implicated pathogenic mechanism in polyneuropathy associated with monoclonal gammopathy. Recognition of antigen depends on immunoglobulin variable regions, encoded by V genes. We studied V(H)DJ(H) and V(L)J(L) gene use in monoclonal B cells by clonal analysis in 20 patients with polyneuropathy and IgM monoclonal gammopathy. V genes associated with bacterial responses appear over-represented and V(H)3-23 was preferentially used, without association with specific D, J(H) or V(L)J(L). V genes revealed somatic mutation and intraclonal variation was found in 9 of 20 patients. Polyneuropathy associated with monoclonal gammopathy may be caused by an immune response to bacterial antigens, which recruit somatically mutated autoreactive B cells.

Fas polymorphisms are associated with the presence of anti-ganglioside antibodies in Guillain-Barre syndrome.

Polymorphisms in genes involved in regulation of immune homeostasis may be a susceptibility factor in the induction of cross-reactive anti-ganglioside antibodies after infection in patients with Guillain-Barre syndrome (GBS). In this study we assessed whether polymorphisms in the promoter region of Fas and FasL and sFas and sFasL are related to GBS or its distinct clinical or serological subgroups. We show that the A(-670)G SNP in the promoter region of Fas and high levels of sFas are associated with the presence of anti-ganglioside antibodies, suggesting that Fas-FasL interaction is involved in the production of cross-reactive antibodies in GBS.