Antibodies in Autoimmune Neuropathies: What to Test, How to Test, Why to Test.

Autoimmune neuropathies are a heterogeneous group of immune-mediated disorders of the peripheral nerves. Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) are the archetypal acute and chronic forms. Over the past few decades, pathogenic antibodies targeting antigens of the peripheral nervous system and driving peripheral nerve damage in selected patients have been described. Moreover, the detection of these antibodies has diagnostic and therapeutic implications that have prompted a modification of the GBS and CIDP diagnostic algorithms. GBS diagnosis is based in clinical criteria, and systematic testing of anti-ganglioside antibodies is not required. Nonetheless, a positive anti-ganglioside antibody test may support the clinical suspicion when diagnosis of GBS (GM1 IgG), Miller Fisher (GQ1b IgG), or acute sensory-ataxic (GD1b IgG) syndromes is uncertain. Anti-myelin-associated glycoprotein (MAG) IgM and anti-disialosyl IgM antibodies are key in the diagnosis of anti-MAG neuropathy and chronic ataxic neuropathy, ophthalmoplegia, M-protein, cold agglutinins, and disialosyl antibodies spectrum neuropathies, respectively, and help differentiating these conditions from CIDP. Recently, the field has been boosted by the discovery of pathogenic antibodies targeting proteins of the node of Ranvier contactin-1, contactin-associated protein 1, and nodal and paranodal isoforms of neurofascin (NF140, NF186, or NF155). These antibodies define subgroups of patients with specific clinical (most importantly poor or partial response to conventional therapies and excellent response to anti-CD20 therapy) and pathologic (node of Ranvier disruption in the absence of inflammation) features that led to the definition of the "autoimmune nodopathy" diagnostic category and to the incorporation of nodal/paranodal antibodies to clinical routine testing. The purpose of this review was to provide a practical vision for the general neurologist of the use of antibodies in the clinical assessment of autoimmune neuropathies.

Distribution characteristics of antinuclear antibodies in Guillain-Barré syndrome and its relationship with disease severity.

BACKGROUND: Guillain-Barré syndrome (GBS), an acquired immune-mediated autoimmune disorder affecting the peripheral nervous system (PNS), is associated with autoimmunity. The presence of autoantibodies in the blood is an important feature of autoimmune diseases. Herein, we explored the distribution characteristics of the antinuclear antibodies (ANAs) in GBS and the correlation between ANAs and disease severity. MATERIALS AND METHODS: We retrospectively analyzed the clinical data of 170 GBS patients. According to ANAs, GBS patients were divided into ANAs positive and negative groups. The clinical characteristics of these two groups were compared. The distribution difference was also compared between male and female GBS patients. In addition, all enrolled patients were divided into more severe group and milder group according to whether the Hughes score at nadir ≥ 3 or not. Gender, age, and ANAs were compared between the two groups. RESULTS: In this study, the positive rate of ANAs was 27.1 % in 170 GBS patients, among which anti-SSA-52/Ro52 antibody and antimitochondrial antibody M2 made up the largest proportion. In the ANAs positive group, GBS patients had longer days of hospitalization, more respiratory function involvement, and higher level of CSF IgG than the ANAs negative group. Compared to the ANAs negative group, Medical Research Council (MRC) scores on admission and at nadir were lower, and Hughes functional Grading Scale (HFGS) scores on admission and at nadir were higher in GBS patients with ANAs positive group. Erasmus GBS Respiratory Insufficiency Score (EGRIS) in ANAs positive GBS patients group was significantly higher than ANAs negative group. Gender had no effects on the distribution of ANAs in GBS patients. Moreover, we found that the anti-SSA-60 antibodies and age were positively correlated with GBS severity. In addition, in the anti-SSA-60 antibody positive group, GBS patients had longer days of hospitalization, more respiratory function involvement, higher HFGS scores on admission/at nadir, and lower MRC scores at nadir compared with the anti-SSA-60 antibody negative group. CONCLUSION: Anti-SSA-52/Ro52 antibody and antimitochondrial antibody M2 were the most common ANAs in GBS patients. Anti-SSA-60 antibodies and age positively correlated with GBS severity. Positive anti-SSA-60 antibodies and age were independent predictors of GBS patient severity.

A case of variant of GBS with positive serum ganglioside GD3 IgG antibody.

BACKGROUND: Acute bulbar palsy-plus (ABPp) syndrome is an unusual variant of Guillain-Barré syndrome (GBS). Anti-GT1a and anti-GQ1b antibodies have been reported in patients with ABPp, but without reports related to GD3 antibodies. METHODS: Clinical data of a patient diagnosed as ABPp syndrome were reviewed clinically. And we summarized the GBS patients with ABP and facial paralysis reported in the literature. RESULTS: We reported a 13-year-old girl presented with asymmetric bifacial weakness, bulbar palsy and transient limb numbness, and had positive serum IgG anti-GD3 antibody. Through reviewing the GBS patients with ABP and facial paralysis reported previously, we found that facial palsy could be unilateral or bilateral. The bilateral facial palsy could present successively or simultaneously, and could be symmetrical or asymmetrical. Other common symptoms included ophthalmoplegia, sensory abnormality and ataxia. IgG anti-GT1a and IgG anti-GQ1b antibodies were the most frequent. Most of the patients had full recovery within two weeks to one year of follow-up. CONCLUSIONS: We reported a patient with asymmetric bifacial palsy and bulbar palsy, which seemed to fit the diagnosis of ABPp syndrome. This was the first report of ABPp variant of GBS with positive serum ganglioside GD3 IgG antibody.

Clinical, paraclinical and outcome features of 166 patients with acute anti-GQ1b antibody syndrome.

BACKGROUND & PURPOSE: In this retrospective study, we aimed at defining the clinical, paraclinical and outcome features of acute neurological syndromes associated with anti-GQ1b antibodies. RESULTS: We identified 166 patients with neurological symptoms appearing in less than 1 month and anti-GQ1b antibodies in serum between 2012 and 2022. Half were female (51%), mean age was 50 years (4-90), and the most frequent clinical features were areflexia (80% of patients), distal upper and lower limbs sensory symptoms (78%), ophthalmoplegia (68%), sensory ataxia (67%), limb muscle weakness (45%) and bulbar weakness (45%). Fifty-three patients (32%) presented with complete (21%) and incomplete (11%) Miller Fisher syndrome (MFS), thirty-six (22%) with Guillain-Barre syndrome (GBS), one (0.6%) with Bickerstaff encephalitis (BE), and seventy-three (44%) with mixed MFS, GBS & BE clinical features. Nerve conduction studies were normal in 46% of cases, showed demyelination in 28%, and axonal loss in 23%. Anti-GT1a antibodies were found in 56% of cases, increased cerebrospinal fluid protein content in 24%, and Campylobacter jejuni infection in 7%. Most patients (83%) were treated with intravenous immunoglobulins, and neurological recovery was complete in 69% of cases at 1 year follow-up. One patient died, and 15% of patients relapsed. Age > 70 years, initial Intensive Care Unit (ICU) admission, and absent anti-GQ1b IgG antibodies were predictors of incomplete recovery at 12 months. No predictors of relapse were identified. CONCLUSION: This study from Western Europe shows acute anti-GQ1b antibody syndrome presents with a large clinical phenotype, a good outcome in 2/3 of cases, and frequent relapses.

Antiganglioside antibody frequency in routine clinical care settings.

BACKGROUND AND PURPOSE: Antiganglioside antibodies (AGAs) might be involved in the etiopathogenesis of many neurological diseases, such as Miller-Fisher syndrome (MFS) and Guillain-Barré syndrome (GBS). Available comprehensive reference data regarding AGA positivity rates and cross-responsiveness among AGAs (where one line immunoblot is positive for ≥1 AGA) during routine clinical care are scant. METHODS: In this 10-year monocentric retrospective study, 3560 immunoglobulin (Ig) G and IgM line blots (GA Generic Assays' Anti-Ganglioside Dot kit) obtained using cerebrospinal fluid (CSF) and serum samples from 1342 patients were analyzed for AGA positivity in terms of 14 diagnosis categories and AGA cross-responsiveness. RESULTS: Of all 3560 line blots 158 (4.4%) and of all CSF samples 0.4% (4/924) CSF line blots were AGA positive. For serum IgG, blots with positivity rates higher than the standard deviation of 15.6% were associated with MFS (GD3, GD1a, GT1a and GQ1b) and acute motor axonal neuropathy (AMAN) (GM1, GD1a and GT1a). For serum IgM, blots with positivity rates higher than the standard deviation of 8.1% were associated with AMAN (GM2, GT1a and GQ1b), MFS (GM1, GT1a and GQ1b), multifocal motor neuropathy (MMN) (GM1, GM2 and GQ1b) and chronic inflammatory demyelinating polyneuropathy (CIDP) (GM1). Cross-responsiveness was observed in 39.6% of all positive serum AGA. CONCLUSIONS: Testing for AGAs during routine clinical care rarely led to positive findings, both in serum and even less in CSF, except for the diagnoses AMAN, MFS, MMN and CIDP. Nonspecific findings found as cross-responsiveness between different AGA samples occur frequently, impacting the positivity of most AGA subtypes.

Autoreactive T cells target peripheral nerves in Guillain-Barré syndrome.

Guillain-Barré syndrome (GBS) is a rare heterogenous disorder of the peripheral nervous system, which is usually triggered by a preceding infection, and causes a potentially life-threatening progressive muscle weakness1. Although GBS is considered an autoimmune disease, the mechanisms that underlie its distinct clinical subtypes remain largely unknown. Here, by combining in vitro T cell screening, single-cell RNA sequencing and T cell receptor (TCR) sequencing, we identify autoreactive memory CD4+ cells, that show a cytotoxic T helper 1 (TH1)-like phenotype, and rare CD8+ T cells that target myelin antigens of the peripheral nerves in patients with the demyelinating disease variant. We characterized more than 1,000 autoreactive single T cell clones, which revealed a polyclonal TCR repertoire, short CDR3ß lengths, preferential HLA-DR restrictions and recognition of immunodominant epitopes. We found that autoreactive TCRß clonotypes were expanded in the blood of the same patient at distinct disease stages and, notably, that they were shared in the blood and the cerebrospinal fluid across different patients with GBS, but not in control individuals. Finally, we identified myelin-reactive T cells in the nerve biopsy from one patient, which indicates that these cells contribute directly to disease pathophysiology. Collectively, our data provide clear evidence of autoreactive T cell immunity in a subset of patients with GBS, and open new perspectives in the field of inflammatory peripheral neuropathies, with potential impact for biomedical applications.

Agentes causales más frecuentes del síndrome de Guillain-Barré en un hospital de Veracruz, México / The most frequent causative agents of Guillain-Barré syndrome in a Mexican general hospital

Introducción. Con posterioridad a la oleada del virus del Zika y el incremento en la incidencia de síndrome de Guillain-Barré (SGB), se ha estudiado la relación causal, pero no se ha encontrado una plena correlación etiológica. Pacientes y métodos. Del 1 de enero al 31 de diciembre de 2017, se incluyeron pacientes con SGB. Además de las serologías básicas, se solicitaron determinaciones de enterovirus, virus del herpes, Campylobacter, hepatitis B y C, TORCH, virus de la inmunodeficiencia humana, Brucella y Salmonella. Resultados. Cohorte de siete pacientes de sexo masculino. A cinco pacientes se les analizó el líquido cefalorraquídeo, que era normal. A todos se les realizó una tomografía encefálica, también normal, y se realizó neuroconducción, que mostró polineuropatía inflamatoria desmielinizante aguda en cuatro casos y neuropatía motora axonal aguda en uno. Todos recibieron inmunoglobulinas intravenosas; tuvieron buen pronóstico cinco casos y hubo dos defunciones. No se informó de casos positivos al virus del Zika. Hubo un caso positivo al dengue, uno al chikungunya, cinco a Campylobacter y uno a enterovirus. Se informó de coinfecciones de dengue + Campylobacter en un caso y de chikungunya + Campylobacter en otro. Conclusiones. La presente cohorte demuestra que no fue posible establecer una relación causal entre el SGB y el virus del Zika, pero se identificaron otros agentes causales víricos y bacterianos, como dengue, chikungunya y enterovirus, y fue aún más destacable la identificación de los casos de Campylobacter

Introduction. After Zika virus outbreak and the increase in the incidence of Guillain-Barré syndrome (GBS), the causal relationship has been studied, however a full etiological correlation has not been found. Patients and methods. From January 1 to December 31, 2017, patients with GBS were included. In addition to the basic serologies, enterovirus, herpes, Campylobacter, hepatitis B and C, TORCH, HIV, Brucella and Salmonella were requested Results. Cohort of seven male patients. Five patients analyzed cerebrospinal fluid reporting normal; all of them underwent brain scan, reporting normal. Neuroconduction was performed, resulting in acute inflammatory demyelinating polyneuropathy in four cases and acute motor axonal neuropathy in one case. All received intravenous immunoglobulins, five cases had a good prognosis and two deaths. No positive cases were reported to Zika virus. A positive case was reported to dengue and another to chikungunya. Five positive cases were reported to Campylobacter. One case positive to enterovirus. Dengue + Campylobacter coinfections were reported in one case and chikungunya + Campylobacter in another case. Conclusions. The present cohort shows that it was not possible to establish a causal relationship between GBS and Zika virus, but other viral and bacterial causal agents were identified, such as dengue, chikungunya and enterovirus, with the identification of Campylobacter cases even more remarkable

Analysis of the albumin level, neutrophil-lymphocyte ratio, and platelet-lymphocyte ratio in Guillain-Barré syndrome / Análise do nível de albumina, da relação neutrófilo-linfócito e linfócito-plaquetas na síndrome de Guillain-Barré

ABSTRACT The purpose of this study was to investigate the prognostic value of the pretreatment and post-treatment albumin level, neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) in subtypes of Guillain-Barré syndrome (GBS). A retrospective analysis of 62 patients with GBS treated between 2011 and 2015 in Dicle University Hospital, Turkey, was carried out. The pretreatment and post-treatment albumin, NLR, and PLR were documented, together with acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor axonal neuropathy, motor sensory axonal neuropathy, and Hughes’ scores. Post-treatment albumin levels in GBS were significantly reduced, and albumin level was negatively correlated with the Hughes scores. Elevated pretreatment NLRs and PLRs were significantly associated with AIDP. There were no correlations between the Hughes scores, NLR, and PLR. The results point to a negative correlation between albumin levels and GBS disability and suggest that the NLR and PLR may be promising blood biomarkers of AIDP.

RESUMO O objetivo deste estudo foi investigar o valor prognóstico dos níveis pré e pós-tratamento de albumina , da relação neutrófilo/linfócito (RNL) e da relação plaqueta/linfócito (RPL) em subtipos de síndrome de Guillain-Barré (SGB). Realizou-se uma análise retrospectiva de 62 pacientes com GBS, tratados entre 2011 e 2015 no Hospital da Universidade Dicle, na Turquia. Os valores pré e pós-tratamento de albumina, RNL e RPL foram documentados, juntamente com polirradiculoneuropatia desmielinizante inflamatória aguda, (PDIA) neuropatia axonal motora aguda, neuropatia axonal sensorial motora e pontuações de Hughes. Os níveis de albumina reduziram significativamente pós-tratamento e correlacionaram-se negativamente com as pontuações de Hughes. RNLs e RPLs pré-tratamento elevados foram significativamente associados à PDIA. Não houve correlação entre as pontuações de Hughes, RNL e RPL. Os resultados apontam uma correlação negativa entre os níveis de albumina e a deficiência na SGB e sugerem que a RNL e a RPL possam ser promissores biomarcadores sanguíneos para PDIA.