Risk of peripheral neuropathy in patients with psoriasis and psoriatic arthritis. A prospective cohort study

INTRODUCTION/AIMS

Laboratory and clinical data suggest a link between neurologically mediated inflammation and psoriasis, but the risk and features of peripheral neuropathy in psoriasis or psoriatic arthritis remain unknown. The aim of this exploratory study was to evaluate the risk and to describe the features of peripheral neuropathy in patients with psoriasis and psoriatic arthritis.

METHODS

One hundred patients with psoriasis and/or psoriatic arthritis and 100 control subjects were consecutively enrolled. Diagnostic confirmation included electrophysiological examination, skin biopsy, and nerve ultrasound for confirmed polyneuropathy.

RESULTS

Nine patients were diagnosed with confirmed polyneuropathy, while none of the control subjects had the condition (relative risk [RR] = 19.00, 95% confidence interval [CI] = 1.12-322.11). Specific relative risks for polyneuropathy were 22.09 (95% CI = 1.17-416.43) in psoriasis patients and 18.75 (95% CI = 1.07-327.62) in psoriatic arthritis patients. The observed polyneuropathy in all nine patients was length-dependent, symmetrical, and predominantly sensory, with minimal or no disability. Comorbidities and exposure to therapies known to increase the risk of polyneuropathy were more frequent in psoriasis and/or psoriatic arthritis patients compared to controls (42% vs. 4%, p = .0001). Analyzing data after excluding possible contributory causes, the risk of polyneuropathy in patients with psoriasis and/or psoriatic arthritis was not significant.

DISCUSSION

Psoriasis and psoriatic arthritis appear to be associated with an increased risk of polyneuropathy. This increased risk seems to be linked to the higher prevalence of contributing factors for polyneuropathy, rather than a direct increase in neuropathy risk specifically related to psoriasis and psoriatic arthritis.

Cytokines and chemokines in patients with chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy: A systematic review

Advances in the understanding of cytokines have revolutionized mechanistic treatments for chronic inflammatory and autoimmune diseases, as exemplified by rheumatoid arthritis. We conducted a systematic literature review on the role of cytokines and chemokines in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). Ovid Medline, EMBASE and Web of Science were searched until August 31, 2022 for human studies investigating cytokines levels in CIDP or MMN. Fifty-five articles on 1061 CIDP patients and 86 MMN patients were included, with a median of 18 patients per study (range 3-71). Studies differed in the inclusion criteria, type of assay, manufacturer, control subjects, and tested biological material. Only a minority of studies reported data on disease activity. Interleukin (IL)-6, IL-17, CXCL10, and tumor necrosis factor alpha (TNF-α), were elevated in CIDP compared to controls in most of the studies. IL-6 and TNF-α levels are also correlated with disability. In MMN patients, IL-1Ra was elevated in the majority of the reports. While acknowledging the challenges in comparing studies and the various limitations of the studies, including small patient numbers, particularly in MMN, our review suggests that IL-6, IL-17, CXCL10, and TNF-α might play a role in CIDP pathogenesis. Larger studies are needed in MMN.

Prospective open-label trial with rituximab in patients with chronic inflammatory demyelinating polyradiculoneuropathy not responding to conventional immune therapies

BACKGROUND

To evaluate the efficacy of rituximab in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients not responding to conventional immune therapies.

METHODS

An open-label, prospective exploratory study was conducted with intravenous rituximab on 17 CIDP patients who had not responded to at least two first-line therapies. The primary endpoint was to determine the proportion of patients who showed improvement 6 months after rituximab therapy. The percentage of responders to rituximab, along with a 95% CI, was reported and compared with the 30% response rate after other immunosuppressive drugs previously documented in the literature.

RESULTS

13 of the 17 treated patients (76.5%) showed improvement at 6 months (95% CI 50.1 to 93.2). Among the 14 patients who completed the 12-month follow-up (2 were lost to follow-up after showing improvement at months 8 and 10, and 1 deteriorated at 6 months), 13 (92.9%) demonstrated improvement at 12 months (95% CI 66.1 to 99.8). Nerve conduction parameters improved by at least 20% in two nerves in 6 out of 15 (40%) patients at 6 months and in 7 out of 13 (53.9%) at 12 months. None of the treated patients withdrew from the study due to side effects. There was a significant reduction of circulating CD19+ cells 15 days, 2, 6 and 12 months after treatment.

CONCLUSION

Rituximab seems to be a safe therapy in most patients with CIDP not responding to conventional immune therapies. The high percentage of patients who improved in this study suggests a possible positive effect of rituximab which is worth investigating in future randomised controlled clinical trials.

TRIAL REGISTRATION NUMBER

NCT05877040.

Chronic inflammatory demyelinating polyneuropathy and HEV antibody status: A case-control study from Lazio, Italy

INTRODUCTION

Few studies have pointed to the possible role of infectious diseases in triggering Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP). Given the association of Hepatitis E Virus (HEV) with Guillain Barrè syndrome, we conducted a case-control study to determine the possible association of HEV infection with CIDP, analyzing possible risk factors for acquiring HEV infection in both CIDP patients and controls.

MATERIALS AND METHODS

82 CIDP and 260 from the general population have provided some personal information (demographics, anamnestic data and recognized risk factors for HEV infection) and underwent venipuncture blood sampling for virological assays testing for anti-HEV IgG and IgM with ELISA and RNA-HEV performing RT-PCR.

RESULTS

Anti-HEV IgG seropositivity resulted in 32 CIDP patients (39.0%) and in 45 controls (17.3%), indicating a significant association between anti-HEV IgG positivity and CIDP (OR 3.04; 95% CI 1.70-5.43, p-value <0.001), but in multivariate logistic regression the only significant associations with anti-HEV positivity were eating pork liver sausages (OR 10.443, 95% CI 2.268-60.12, p-value 0.004) and IVIg/SCIg administration (OR 31.32, 95% CI 7.914-171.7, p-value <0.001).

DISCUSSION

The higher prevalence of anti-HEV IgG in CIDP patients than in controls could be justified by chronically administering IVIg/SCIg with a passive acquisition of anti-HEV antibodies. Furthermore, all the 20 CIDP patients who underwent IVIg/SCIg administration reported HEV risk factors, so that they could have acquired the infection.

CONCLUSIONS

Further studies in a larger CIDP patient sample in treatment with therapy other than IVIg/SCIg are necessary to rule out the possible confounding effect of IVIg/SCIg.

Regular assessment of serum vascular endothelial growth factor levels to monitor POEMS syndrome

BACKGROUND

To investigate the utility of regular serum VEGF (sVEGF) levels assessment in the monitoring of POEMS syndrome.

METHODS

We retrospectively reviewed data of 30 patients with POEMS syndrome whose sVEGF was tested regularly every 6 months. sVEGF levels after treatment were measured and correlated with disability (Overall Neuropathy Limitations Scale, ONLS), clinical impairment (measured with the modified Clinical Response Evaluation Scale, mCRES), and relapse-free survival. The ability of sVEGF to predict disease flares during remission and refractory disease was also analysed.

RESULTS

Patients with normalised serum VEGF levels (< 1000 pg/ml) at 6 months showed prolonged relapse-free survival (at 3-year 94% for complete VEGF response, 57% partial, 0% none, p < 0.001) and greater later clinical improvement (median ΔmCRES complete VEGF response -5 vs partial -4, p = 0.019, and vs no VEGF response -2, p = 0.006). After remission, the sensitivity of 6-month sVEGF monitoring in predicting clinical relapse was 58% with a specificity of 100%. In patients refractory to treatment, the sensitivity in predicting further clinical worsening was 15%. In addition, in 25% of the patients in remission and 16% of those refractory to therapy, sVEGF levels only increased at the time of relapse.

CONCLUSIONS

Regular sVEGF assessment is a valid biomarker in the prediction of disease reactivation in POEMS syndrome and was particularly useful during the phase of remission.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

What do we mean by long COVID? A scoping review of the cognitive sequelae of SARS-CoV-2 infection

BACKGROUND AND PURPOSE

Many COVID-19 patients report persistent symptoms, including cognitive disturbances. We performed a scoping review on this topic, focusing primarily on cognitive manifestations.

METHODS

Abstracts and full texts of studies published on PubMed (until May 2023) addressing cognitive involvement persisting after SARS-CoV-2 infection were reviewed, focusing on terms used to name the cognitive syndrome, reported symptoms, their onset time and duration, and testing batteries employed. Reported psychiatric symptoms, their assessment tools, and more general manifestations were also extracted.

RESULTS

Among the 947 records identified, 180 studies were included. Only one third of them used a label to define the syndrome. A minority of studies included patients according to stringent temporal criteria of syndrome onset (34%), whereas more studies reported a minimum required symptom duration (77%). The most frequently reported cognitive symptoms were memory and attentional-executive disturbances, and among psychiatric complaints, the most frequent were anxiety symptoms, depression, and sleep disturbances. Most studies reported fatigue among general symptoms. Thirty-six studies employed cognitive measures: screening tests alone (n = 19), full neuropsychological batteries (n = 25), or both (n = 29); 30 studies performed psychiatric testing. Cognitive deficits were demonstrated in 39% of subjects, the most frequently affected domains being attention/executive functions (90%) and memory (67%).

CONCLUSIONS

Currently, no agreement exists on a label for post-COVID-19 cognitive syndrome. The time of symptom onset after acute infection and symptom duration are still discussed. Memory and attention-executive complaints and deficits, together with fatigue, anxiety, and depression symptoms, are consistently reported, but the objective evaluation of these symptoms is not standardized.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

Neuropathic Pain in the Emergency Setting: Diagnosis and Management

Neuropathic pain, traditionally considered a chronic condition, is increasingly encountered in the emergency department (ED), accounting for approximately 20% of patients presenting with pain. Understanding the physiology and key clinical presentations of neuropathic pain is crucial for ED physicians to provide optimal treatment. While diagnosing neuropathic pain can be challenging, emphasis should be placed on obtaining a comprehensive medical history and conducting a thorough clinical examination. Patients often describe neuropathic pain as a burning or shock-like sensation, leading them to seek care in the ED after ineffective relief from common analgesics such as paracetamol and NSAIDs. Collaboration between emergency medicine specialists, neurologists, and pain management experts can contribute to the development of evidence-based guidelines specifically tailored for the emergency department setting. This article provides a concise overview of the common clinical manifestations of neuropathic pain that may prompt patients to seek emergency care.

Autonomic nervous system involvement in chronic inflammatory demyelinating polyradiculoneuropathy: a literature review

BACKGROUND AND AIMS

Although dysautonomia is a well-recognized complication of acute demyelinating polyradiculoneuropathy, it is rarely reported and evaluated in chronic demyelinating neuropathies. The purpose of this review is to search and synthesize the current literature on the prevalence and type of autonomic dysfunction (AD) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

PubMed and Web of Science were searched for studies reporting AD in CIDP.

RESULTS

Twelve studies, including 346 patients with CIDP, were found eligible for the review. Seven studies used autonomic tests only as an additional component of the comprehensive clinical evaluation, and found that dysautonomia in CIDP may indicate the presence of a comorbid disease (e.g., diabetes) and facilitate the differentiation of CIDP from other neuropathies (e.g., amyloid neuropathy). Five studies performed quantitative assessment of autonomic function in CIDP as a primary goal. Two studies have used the Composite Autonomic Severity Score (CASS) to assess severity and distribution of dysautonomia. The reported prevalence of dysautonomia in CIDP during quantitative assessment of autonomic function ranged from 25 to 89%, depending on the battery of tests used, with CASS not exceeding 4 points. The abnormalities in autonomic tests indicated both sympathetic and parasympathetic dysfunction and did not correlate with the duration, severity and variant of CIDP.

CONCLUSIONS

Clinical or subclinical involvement of the ANS has been shown to be common and relatively mild in CIDP. The impact of autonomic impairment on disability and of its possible response to therapy in CIDP needs to be further investigated.

Unclassified clinical presentations of chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

To assess the ability of the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) clinical criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) to include within their classification the whole spectrum of clinical heterogeneity of the disease and to define the clinical characteristics of the unclassifiable clinical forms.

METHODS

The 2021 EAN/PNS clinical criteria for CIDP were applied to 329 patients fulfilling the electrodiagnostic (and in some cases also the supportive) criteria for the diagnosis of CIDP. Clinical characteristics were reviewed for each patient not strictly fulfilling the clinical criteria ('unclassifiable').

RESULTS

At study inclusion, 124 (37.5%) patients had an unclassifiable clinical presentation, including 110 (89%) with a typical CIDP-like clinical phenotype in whom some segments of the four limbs were unaffected by weakness ('incomplete typical CIDP'), 10 (8%) with a mild distal, symmetric, sensory or sensorimotor polyneuropathy confined to the lower limbs with cranial nerve involvement ('cranial nerve predominant CIDP') and 4 (1%) with a symmetric sensorimotor polyneuropathy limited to the proximal and distal areas of the lower limbs ('paraparetic CIDP'). Eighty-one (65%) patients maintained an unclassifiable presentation during the entire disease follow-up while 13 patients progressed to typical CIDP. Patients with the unclassifiable clinical forms compared with patients with typical CIDP had a milder form of CIDP, while there was no difference in the distribution patterns of demyelination.

CONCLUSIONS

A proportion of patients with CIDP do not strictly fulfil the 2021 EAN/PNS clinical criteria for diagnosis. These unclassifiable clinical phenotypes may pose diagnostic challenges and thus deserve more attention in clinical practice and research.

CSF Findings in Relation to Clinical Characteristics, Subtype, and Disease Course in Patients With Guillain-Barré Syndrome

BACKGROUND AND OBJECTIVES

To investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the International GBS Outcome Study.

METHODS

Albuminocytologic dissociation (ACD) was defined as an increased protein level (>0.45 g/L) in the absence of elevated white cell count (<50 cells/μL). We excluded 124 (8%) patients because of other diagnoses, protocol violation, or insufficient data. The CSF was examined in 1,231 patients (89%).

RESULTS

In 846 (70%) patients, CSF examination showed ACD, which increased with time from weakness onset: ≤4 days 57%, >4 days 84%. High CSF protein levels were associated with a demyelinating subtype, proximal or global muscle weakness, and a reduced likelihood of being able to run at week 2 (odds ratio [OR] 0.42, 95% CI 0.25-0.70; p = 0.001) and week 4 (OR 0.44, 95% CI 0.27-0.72; p = 0.001). Patients with the Miller Fisher syndrome, distal predominant weakness, and normal or equivocal nerve conduction studies were more likely to have lower CSF protein levels. CSF cell count was <5 cells/μL in 1,005 patients (83%), 5-49 cells/μL in 200 patients (16%), and ≥50 cells/μL in 13 patients (1%).

DISCUSSION

ACD is a common finding in GBS, but normal protein levels do not exclude this diagnosis. High CSF protein level is associated with an early severe disease course and a demyelinating subtype. Elevated CSF cell count, rarely ≥50 cells/μL, is compatible with GBS after a thorough exclusion of alternative diagnoses.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that CSF ACD (defined by the Brighton Collaboration) is common in patients with GBS.

Risk of disease relapse, safety and tolerability of SARS-CoV-2 vaccination in patients with chronic inflammatory neuropathies

BACKGROUND

To evaluate the risk of relapse after SARS-CoV-2 vaccination, and its safety and tolerability, in patients with chronic inflammatory neuropathies.

METHODS

In this multicenter, cohort, and case-crossover study, the risk of relapse associated with SARS-CoV-2 vaccination was assessed by comparing frequency of relapse in CIDP and MMN patients who underwent or did not undergo vaccination. Frequency of relapse in the three months prior and after vaccination, and safety and tolerability of SARS-CoV-2 vaccination were also assessed.

RESULTS

336 patients were included (278 CIDP; 58 MMN). 307 (91%) patients underwent SARS-CoV-2 vaccination. Twenty-nine patients (9%) did not undergo vaccination. Mild and transient relapses were observed in 16 (5%) patients (13 CIDP; 3 MMN) after SARS-CoV-2 vaccination and in none of the patients who did not undergo vaccination (RR= 3.21, 95% CI, 0.19-52.25). There was no increase in the specific risk of relapse associated with type of vaccine or diagnosis. Comparison with the 3-month control period preceding vaccination revealed an increased risk of relapse after vaccination (RR= 4.00; 95% CI, 1.35-11.82), which was restricted to CIDP patients (RR= 3.25, 95% CI, 1.07-9.84). The safety profile of SARS-CoV-2 vaccination was characterized by short-term, mild-to-moderate local and systemic adverse events.

CONCLUSIONS

SARS-CoV-2 vaccination in CIDP and MMN patients does not seem to be associated with an increased risk of relapse at primary endpoint, although a slightly increased risk in CIDP patients was found compared to the 3 months before vaccination.

A diagnostic score for anti-myelin-associated-glycoprotein neuropathy or chronic inflammatory demyelinating polyradiculoneuropathy in patients with anti-myelin-associated-glycoprotein antibody

BACKGROUND AND PURPOSE

A diagnostic score was developed to discriminate anti-myelin-associated-glycoprotein (MAG) neuropathy from chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and applied it to patients with atypical anti-MAG neuropathy.

METHODS

The clinical and electrophysiological features of patients with a diagnosis of typical anti-MAG neuropathy were compared to those of patients with a diagnosis of CIDP. The association of each feature with the diagnosis was assessed in the two groups. Features showing a significant association with the diagnosis were included in a multivariable logistic regression model and adjusted odds ratios were estimated for each feature. A score ranging from 1 to 3 was applied to each feature based on the magnitude of the estimated odds ratios. The score was then applied to patients with a clinical diagnosis of CIDP who also had high anti-MAG antibody titers (CIDP-MAG).

RESULTS

Thirty-one anti-MAG neuropathy patients, 45 typical CIDP patients and 16 CIDP-MAG patients were included. Scores in anti-MAG antibody patients ranged from 1 to 5 and in CIDP patients from -7 to -1. Using the score, 4/16 CIDP-MAG patients were diagnosed to have anti-MAG neuropathy and 12/16 patients to have CIDP. Response to intravenous immunoglobulin in the CIDP-MAG patients classified as CIDP was similar to that of definite CIDP patients and higher than that of anti-MAG neuropathy patients.

CONCLUSIONS

Our score allowed an accurate discrimination to be made, amongst patients with anti-MAG antibodies, of those affected by CIDP and the patients with anti-MAG neuropathy. This score may help proper treatment to be chosen for patients with anti-MAG antibodies with a CIDP-like presentation.

The circular RNA landscape in multiple sclerosis: Disease-specific associated variants and exon methylation shape circular RNA expression profile

BACKGROUND

Circular RNAs (circRNAs) are a class of non-coding RNAs increasingly emerging as crucial actors in the pathogenesis of human diseases, including autoimmune and neurological disorders as multiple sclerosis (MS). Despite several efforts, the mechanisms regulating circRNAs expression are still largely unknown and the circRNA profile and regulation in MS-relevant cell models has not been completely investigated. In this work, we aimed at exploring the global landscape of circRNA expression in MS patients, also evaluating a possible correlation with their genetic and epigenetic background.

METHODS

We performed RNA-seq experiments on circRNA-enriched samples, derived from peripheral blood mononuclear cells (PBMCs) of 10 MS patients and 10 matched controls and performed differential circRNA expression. The genetic background was evaluated using array genotyping, and an expression quantitative trait loci (eQTL) analysis was carried out.

RESULTS

Expression analysis revealed 166 differentially expressed circRNAs in MS patients, 125 of which are downregulated. One of the top dysregulated circRNAs, hsa_circ_0007990, derives from the PGAP3 gene, encoding a protein relevant for the control of autoimmune responses. The downregulation of this circRNA was confirmed in two independent replication cohorts, suggesting its implementation as a possible RNA-based biomarker. The eQTL analysis evidenced a significant association between 89 MS-associated loci and the expression of at least one circRNA, suggesting that MS-associated variants could impact on disease pathogenesis by altering circRNA profiles. Finally, we found a significant correlation between exon methylation and circRNA expression levels, supporting the hypothesis that epigenetic features may play an important role in the definition of the cell circRNA pool.

CONCLUSION

We described the circRNA expression profile of PBMCs in MS patients, suggesting that MS-associated variants may tune the expression levels of circRNAs acting as "circ-QTLs", and proposing a role for exon-based DNA methylation in regulating circRNA expression.

Safety, Efficacy, And Pharmacokinetics of Argx-117 in Adults With Multifocal Motor Neuropathy: A Global, Multicenter, Placebo Controlled Phase 2 Study (Arda)

Objective

To report the study design of a Phase 2, multicenter, randomized, placebo controlled, parallel-group study (ARDA,NCT05225675) will assess the safety, efficacy, PK, and PD of ARGX-117 in adults with MMN.

Background

Multifocal motor neuropathy (MMN) is a chronic, immune-mediated neuropathy characterized by progressive asymmetric weakness predominantly affecting the distal upper limbs. MMN is often associated with anti-GM1 IgM antibodies targeting the axolemma at the node of Ranvier, leading to activation of the classical complement pathway which drives subsequent damage to the axon. IVIg is the only proven effective therapy. ARGX-117 is a novel monoclonal antibody that inhibits complement factor 2 (C2). Using an in vitro model for MMN, ARGX-117 was shown to block IgM-mediated classical pathway complement activation on both motor neurons and Schwann cells. ARGX-117 is being studied in adults with MMN in a Phase 2, multicenter, randomized, placebo controlled, parallel-group study.

Design/Methods

Forty-eight participants will be recruited and assigned to one of two dosing cohorts (24 participants each) and randomized 2:1 within each cohort to receive either ARGX-117 or placebo. Key inclusion criteria include: diagnosis of probable or definite MMN per 2010 EFNS/PNS guidelines, stable IVIg regimen, and IVIg treatment dependency. The primary objective is safety based on adverse event monitoring and other safety assessments. Secondary objectives include assessment of efficacy measured as strength and functional disability, pharmacokinetics, pharmacodynamics (C2 and CH50), and immunogenicity of ARGX-117. After completing the 16-week treatment period, participants may enroll in an open-label extension study, or enter the safety follow-up period.

Results

This ongoing phase 2 study will assess the safety and efficacy of ARGX-117 in participants with MMN.

Conclusions

The results of this study will inform and direct future studies of ARGX-117 in this patient population.

Update on therapy of chronic immune-mediated neuropathies

Chronic immune-mediated neuropathies, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), neuropathies associated with monoclonal gammopathy, and multifocal motor neuropathy (MMN), are a group of disorders deemed to be caused by an immune response against peripheral nerve antigens. Several immune therapies have been reported to be variably effective in these neuropathies including steroids, plasma exchange, and high-dose intravenous (IVIg) or subcutaneous (SCIg) immunoglobulins. These therapies are however far from being invariably effective and may be associated with a number of side effects leading to the use of immunosuppressive agents whose efficacy has not been so far confirmed in randomized trials. More recently, new biological agents, such as rituximab, have proved to be effective in patients with neuropathy associated with IgM monoclonal gammopathy and are currently tested in CIDP.

Comparison of the diagnostic accuracy of the 2021 EAN/PNS and 2010 EFNS/PNS diagnostic criteria for chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVES

To compare the sensitivity and specificity of the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) diagnostic criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with those of the 2010 European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS).

METHODS

Sensitivity and specificity of the two sets of criteria were evaluated in 330 patients with CIDP and 166 axonal peripheral neuropathy controls. Comparison of the utility of nerve conduction studies with different number of nerves examined and of the sensitivity and specificity of the two criteria in typical CIDP and its variants were assessed.

RESULTS

EFNS/PNS criteria had a sensitivity of 92% for possible CIDP and 85% for probable/definite CIDP, while the EAN/PNS criteria had a sensitivity of 83% for possible CIDP and 74% for CIDP. Using supportive criteria, the sensitivity of the EAN/PNS criteria for possible CIDP increased to 85% and that of CIDP to 77%, remaining lower than that of the EFNS/PNS criteria. Specificity of the EFNS/PNS criteria was 68% for possible CIDP and 84% for probable/definite CIDP, while the EAN/PNS criteria had a specificity of 88% for possible CIDP and 98% for CIDP. More extended studies increased the sensitivity of both sets of criteria by 4%-7% but reduced their specificity by 2%-3%. The EFNS/PNS criteria were more sensitive for the diagnosis of typical CIDP while the EAN/PNS criteria were more specific for the diagnosis of distal and sensory CIDP.

CONCLUSIONS

In our population, the EAN/PNS criteria were more specific but less sensitive than the EFNS/PNS criteria. With the EAN/PNS criteria, more extended nerve conduction studies are recommended to obtain an acceptable sensitivity while maintaining a high specificity.

An International Perspective on Preceding Infections in Guillain-Barré Syndrome: The IGOS-1000 Cohort

BACKGROUND AND OBJECTIVES

Infections play a key role in the development of Guillain-Barré syndrome (GBS) and have been associated with specific clinical features and disease severity. The clinical variation of GBS across geographical regions has been suggested to be related to differences in the distribution of preceding infections, but this has not been studied on a large scale.

METHODS

We analyzed the first 1,000 patients included in the International GBS Outcome Study with available biosamples (n = 768) for the presence of a recent infection with Campylobacter jejuni, hepatitis E virus, Mycoplasma pneumoniae, cytomegalovirus, and Epstein-Barr virus.

RESULTS

Serologic evidence of a recent infection with C. jejuni was found in 228 (30%), M. pneumoniae in 77 (10%), hepatitis E virus in 23 (3%), cytomegalovirus in 30 (4%), and Epstein-Barr virus in 7 (1%) patients. Evidence of more than 1 recent infection was found in 49 (6%) of these patients. Symptoms of antecedent infections were reported in 556 patients (72%), and this proportion did not significantly differ between those testing positive or negative for a recent infection. The proportions of infections were similar across continents. The sensorimotor variant and the demyelinating electrophysiologic subtype were most frequent across all infection groups, although proportions were significantly higher in patients with a cytomegalovirus and significantly lower in those with a C. jejuni infection. C. jejuni-positive patients were more severely affected, indicated by a lower Medical Research Council sum score at nadir (p = 0.004) and a longer time to regain the ability to walk independently (p = 0.005). The pure motor variant and axonal electrophysiologic subtype were more frequent in Asian compared with American or European C. jejuni-positive patients (p < 0.001, resp. p = 0.001). Time to nadir was longer in the cytomegalovirus-positive patients (p = 0.004).

DISCUSSION

Across geographical regions, the distribution of infections was similar, but the association between infection and clinical phenotype differed. A mismatch between symptom reporting and serologic results and the high frequency of coinfections demonstrate the importance of broad serologic testing in identifying the most likely infectious trigger. The association between infections and outcome indicates their value for future prognostic models.

Guillain-Barré Syndrome and COVID-19: a one-year observational multicenter study

Background and purpose

Many single cases and small series of Guillain–Barré syndrome (GBS) associated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection were reported during the coronavirus disease 19 (COVID‐19) outbreak worldwide. However, the debate regarding the possible role of infection in causing GBS is still ongoing. This multicenter study aimed to evaluate epidemiological and clinical findings of GBS diagnosed during the COVID‐19 pandemic in northeastern Italy in order to further investigate the possible association between GBS and COVID‐19.

Methods

Guillain–Barré syndrome cases diagnosed in 14 referral hospitals from northern Italy between March 2020 and March 2021 were collected and divided into COVID‐19‐positive and COVID‐19‐negative. As a control population, GBS patients diagnosed in the same hospitals from January 2019 to February 2020 were considered.

Results

The estimated incidence of GBS in 2020 was 1.41 cases per 100,000 persons/year (95% confidence interval 1.18–1.68) versus 0.89 cases per 100,000 persons/year (95% confidence interval 0.71–1.11) in 2019. The cumulative incidence of GBS increased by 59% in the period March 2020–March 2021 and, most importantly, COVID‐19‐positive GBS patients represented about 50% of the total GBS cases with most of them occurring during the two first pandemic waves in spring and autumn 2020. COVID‐19‐negative GBS cases from March 2020 to March 2021 declined by 22% compared to February 2019–February 2020.

Conclusions

Other than showing an increase of GBS in northern Italy in the “COVID‐19 era” compared to the previous year, this study emphasizes how GBS cases related to COVID‐19 represent a significant part of the total, thus suggesting a relation between COVID‐19 and GBS.

Frequency and clinical correlates of anti-nerve antibodies in a large population of CIDP patients included in the Italian database

OBJECTIVE

To investigate the frequency and clinical correlates of anti-nerve autoantibodies in an unselected series of Italian patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) METHODS: Sera from 276 CIDP patients fulfilling the EFNS/PNS criteria and included in the Italian CIDP database were examined for the presence of anti-nerve autoantibodies. Results were correlated with the clinical data collected in the database.

RESULTS

Anti-neurofascin155 (NF155) antibodies were found in 9/258 (3.5%) patients, anti-contactin1 (CNTN1) antibodies in 4/258 (1.6%) patients, and anti-contactin-associated protein1 (Caspr1) in 1/197 (0.5%) patients, while none had reactivity to gliomedin or neurofascin 186. Predominance of IgG4 isotype was present in 7of the 9 examined patients. Anti-NF155 patients more frequently had ataxia, tremor, and higher CSF protein levels than antibody-negative patients. Anti-CNTN1 patients more frequently had a GBS-like onset, pain, and ataxia and had more severe motor impairment at enrollment than antibody-negative patients. They more frequently received plasmapheresis, possibly reflecting a less satisfactory response to IVIg or steroids. IgM antibodies against one or more gangliosides were found in 6.5% of the patients (17/260) and were more frequently directed against GM1 (3.9%). They were frequently associated with a progressive course, with a multifocal sensorimotor phenotype and less frequent cranial nerve involvement and ataxia.

CONCLUSIONS

Anti-paranodal and anti-ganglioside antibodies are infrequent in patients with CIDP but are associated with some typical clinical association supporting the hypothesis that CIDP might be a pathogenically heterogeneous syndrome possibly explaining the different clinical presentations.

Predicting Outcome in Guillain-Barré Syndrome: International Validation of the Modified Erasmus GBS Outcome Score

BACKGROUND AND OBJECTIVES

The clinical course and outcome of the Guillain-Barré syndrome (GBS) are diverse and vary among regions. The modified Erasmus GBS Outcome Score (mEGOS), developed with data from Dutch patients, is a clinical model that predicts the risk of walking inability in patients with GBS. The study objective was to validate the mEGOS in the International GBS Outcome Study (IGOS) cohort and to improve its performance and region specificity.

METHODS

We used prospective data from the first 1,500 patients included in IGOS, aged ≥6 years and unable to walk independently. We evaluated whether the mEGOS at entry and week 1 could predict the inability to walk unaided at 4 and 26 weeks in the full cohort and in regional subgroups, using 2 measures for model performance: (1) discrimination: area under the receiver operating characteristic curve (AUC) and (2) calibration: observed vs predicted probability of being unable to walk independently. To improve the model predictions, we recalibrated the model containing the overall mEGOS score, without changing the individual predictive factors. Finally, we assessed the predictive ability of the individual factors.

RESULTS

For validation of mEGOS at entry, 809 patients were eligible (Europe/North America [n = 677], Asia [n = 76], other [n = 56]), and 671 for validation of mEGOS at week 1 (Europe/North America [n = 563], Asia [n = 65], other [n = 43]). AUC values were >0.7 in all regional subgroups. In the Europe/North America subgroup, observed outcomes were worse than predicted; in Asia, observed outcomes were better than predicted. Recalibration improved model accuracy and enabled the development of a region-specific version for Europe/North America (mEGOS-Eu/NA). Similar to the original mEGOS, severe limb weakness and higher age were the predominant predictors of poor outcome in the IGOS cohort.

DISCUSSION

mEGOS is a validated tool to predict the inability to walk unaided at 4 and 26 weeks in patients with GBS, also in countries outside the Netherlands. We developed a region-specific version of mEGOS for patients from Europe/North America.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that the mEGOS accurately predicts the inability to walk unaided at 4 and 26 weeks in patients with GBS.

TRIAL REGISTRATION INFORMATION

NCT01582763.

Phosphorylated TDP-43 aggregates in peripheral motor nerves of patients with amyotrophic lateral sclerosis

Phosphorylated TDP-43 (pTDP-43) aggregates in the cytoplasm of motor neurons and neuroglia in the brain are one of the pathological hallmarks of amyotrophic lateral sclerosis. Although the axons exceed the total volume of motor neuron soma by several orders of magnitude, systematic studies investigating the presence and distribution of pTDP-43 aggregates within motor nerves are still lacking. The aim of this study is to define the TDP-43/pTDP-43 pathology in diagnostic motor nerve biopsies performed on a large cohort of patients presenting with a lower motor neuron syndrome and to assess whether this might be a discriminating tissue biomarker for amyotrophic lateral sclerosis and non-amyotrophic lateral sclerosis cases.

We retrospectively evaluated 102 lower motor neuron syndrome patients referred to our centre for a diagnostic motor nerve biopsy. Histopathological criteria of motor neuron disease and motor neuropathy were applied by two independent evaluators, who were blind to clinical data. TDP-43 and pTDP-43 were evaluated by immunohistochemistry, and results compared to final clinical diagnosis.

We detected significant differences between amyotrophic lateral sclerosis and non-amyotrophic lateral sclerosis cases in pTDP-43 expression in myelinated fibres: axonal accumulation was detected in 98.2% of patients with amyotrophic lateral sclerosis versus 30.4% of non-amyotrophic lateral sclerosis samples (P < 0.0001), while concomitant positive staining in Schwan cell cytoplasm was found in 70.2% of patients with amyotrophic lateral sclerosis versus 17.4% of patients who did not have amyotrophic lateral sclerosis (P < 0.001). Importantly, we were also able to detect pTDP-43 aggregates in amyotrophic lateral sclerosis cases displaying normal features at standard histopathological analysis.

Our findings demonstrated that a specific pTDP-43 signature is present in the peripheral nervous system of patients with amyotrophic lateral sclerosis, and could be exploited as a specific, accessible tissue biomarker. The detection of pTDP-43 aggregates within motor nerves of living patients with amyotrophic lateral sclerosis, occurring before axonal degeneration, suggests that this is an early event that may contribute to amyotrophic lateral sclerosis pathogenesis.