Early predictive factors of disability in CIDP

Animal models of immune-mediated demyelinating polyneuropathies

Immune-mediated demyelinating polyneuropathies (IMDPs) are rare disorders in which dysregulated adaptive immune responses cause peripheral nerve demyelinating inflammation and axonal injury in susceptible individuals. Despite significant advances in understanding IMDP pathogenesis guided by patient data and representative mammalian models, specific therapies are lacking. Significant knowledge gaps in IMDP pathogenesis still exist, e.g. precise antigen(s) and mechanisms that initially trigger immune system activation and identification of large population disease susceptibility factors. The initial directional cues for antigen-specific effector or autoreactive leukocyte trafficking into peripheral nerves are also unknown. An overview of current animal models, with emphasis on the experimental autoimmune neuritis and spontaneous autoimmune peripheral polyneuropathy models, is provided. Insights on the initial directional cues for peripheral nerve tissue specific autoimmunity using a novel Major Histocompatibility Complex class II conditional knockout mouse strain are also discussed, suggesting an essential research tool to study cell- and time-dependent adaptive immunity in autoimmune diseases.

The neurophysiological lesson from the Italian CIDP database

INTRODUCTION

Electrophysiological diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) may be challenging. Thus, with the aim ofproviding some practical advice in electrophysiological approach to a patient with suspected CIDP, we analyzed electrophysiological data from 499 patients enrolled inthe Italian CIDP Database.

METHODS

We calculated the rate of each demyelinating feature, the rate of demyelinating features per nerve, the diagnostic rate for upper andlower limb nerves, and, using a ROC curve analysis, the diagnostic accuracy of each couple of nerves and each demyelinating feature, for every CIDP subtype.Moreover, we compared the electrophysiological data of definite and probable CIDP patients with those of possible and not-fulfilling CIDP patients, and by a logisticregression analysis, we estimated the odds ratio (OR) to make an electrophysiological diagnosis of definite or probable CIDP.

RESULTS

The ulnar nerve had the highestrate of demyelinating features and, when tested bilaterally, had the highest diagnostic accuracy except for DADS in which peroneal nerves were the most informative.In possible and not-fulfilling CIDP patients, a lower number of nerves and proximal temporal dispersion (TD) measurements had been performed compared to definiteand probable CIDP patients. Importantly, OR for each tested motor nerve and each TD measurement was 1.59 and 1.33, respectively.

CONCLUSION

Our findingsdemonstrated that the diagnosis of CIDP may be missed due to inadequate or incomplete electrophysiological examination or interpretation. At the same time, thesedata taken together could be useful to draw a thoughtful electrophysiological approach to patients suspected of CIDP.

Pediatric CIDP: Diagnosis and Management. A Single-Center Experience

Background: Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare acquired polyneuropathy that especially among youngest children should be differentiated with hereditary neuropathies. Even though upon diagnosis treatment options are similar in children and adults, diagnostic challenges are faced in the pediatric population. Methods: We conducted a retrospective analysis of clinical symptoms, nerve conduction study results, modes of treatment, and final outcome in 37 children aged 3.5-17 years with a final diagnosis of CIDP (18 girls, 19 boys). We established three groups of patients based on age at onset of CIDP: 0-4, 4-13, and 13-18 years. Follow-up ranged from 10 to 222 months. Results: In our analysis, 19/37 patients (51.4%) had an atypical presentation: distal variant of CIDP in 12/37 patients (32.4%) and pure motor variant of CIDP in 5/37 patients (13.5%), and one patient had a pure sensory variant (1/37, 2.7%). Furthermore, 3/37 patients (8.1%) had additional concurring symptoms, including involuntary movements of face muscles (1/37, 2.7%) or hand tremor (2/37, 5.4%). During the follow-up, 23/37 patients (62.2%) received intravenous immunoglobulin (IVIg); 22/37 patients (59.5%) received steroids, 6/37 patients (16.2%) received IVIg and steroids, and 12/37 patients (32.4%) received immunosuppressive drugs, mostly azathioprine, but also methotrexate and rituximab. One patient was treated with plasmapheresis. Complete remission was achieved in 19/37 patients (51.4%) with CIDP in its typical form. Remission with residual symptoms or minimal deficit was observed in 4/37 patients (10.8%), whereas 14/37 patients (37.8%) remain on treatment with gradual improvement. Conclusion: Childhood CIDP may occur in its typical form, but even ~50% of children can present as an atypical variant including distal, pure motor, or pure sensory. Most children have a good prognosis; however, many of them may require long-term treatment. This highlights the importance of an early diagnosis and treatment for childhood CIDP.

The neurophysiological lesson from the Italian CIDP database

Introduction

Electrophysiological diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) may be challenging. Thus, with the aim ofproviding some practical advice in electrophysiological approach to a patient with suspected CIDP, we analyzed electrophysiological data from 499 patients enrolled inthe Italian CIDP Database.

Methods

We calculated the rate of each demyelinating feature, the rate of demyelinating features per nerve, the diagnostic rate for upper andlower limb nerves, and, using a ROC curve analysis, the diagnostic accuracy of each couple of nerves and each demyelinating feature, for every CIDP subtype.Moreover, we compared the electrophysiological data of definite and probable CIDP patients with those of possible and not-fulfilling CIDP patients, and by a logisticregression analysis, we estimated the odds ratio (OR) to make an electrophysiological diagnosis of definite or probable CIDP.

Results

The ulnar nerve had the highestrate of demyelinating features and, when tested bilaterally, had the highest diagnostic accuracy except for DADS in which peroneal nerves were the most informative.In possible and not-fulfilling CIDP patients, a lower number of nerves and proximal temporal dispersion (TD) measurements had been performed compared to definiteand probable CIDP patients. Importantly, OR for each tested motor nerve and each TD measurement was 1.59 and 1.33, respectively.

Conclusion

Our findingsdemonstrated that the diagnosis of CIDP may be missed due to inadequate or incomplete electrophysiological examination or interpretation. At the same time, thesedata taken together could be useful to draw a thoughtful electrophysiological approach to patients suspected of CIDP.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-021-05321-z.

The influence of the COVID-19 pandemic on patients with chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVES

At a time of global health crisis, fear, anxiety, and stress levels increase. The effects of protracted social isolation, and media related misinformation's about the coronavirus disease 2019 (COVID-19) resulting in increased fear/stress related to the insufficiently known illness. The aim was to assess the influence of the COVID-19 health crisis on patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

A cross-sectional study on 29 adult CIDP patients was performed. The Medical Research Council scale was used to evaluate muscle strength. The degree of functional disability was measured using the Inflammatory Neuropathy Cause and Treatment disability scale. The overall quality of life (QoL) was self-estimated on a 0-100 numeric rating scale. We also used a specifically designed 22-question-survey about COVID-19.

RESULTS

Regarding the COVID-19 pandemic, 62% of CIDP patients were concerned. The daily activities of 55% of patients were negatively influenced by the pandemic. During the COVID-19 outbreak, 21% of patients reported their CIDP got worse. In 39% of CIDP patients, the influence of the pandemic on CIDP therapy was reported (reducing the dose or time interval or even discontinuation). The mean value of the self-estimated QoL was 64 ± 19. Independent predictors of worse QoL were age of patients (beta = -0.35, p < 0.05) and fear of the COVID-19 (beta = -0.34, p < 0.05).

CONCLUSION

The COVID-19 pandemic has a significant impact on CIDP patients. Besides the direct influence of the virus and fear of the virus, restrictive measures can indirectly harm the patients with CIDP.

[Autologous hematopoietic stem cell transplantation for chronic inflammatory demyelinating polyneuropathy]

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a dysimmune neuropathy with sensory and/or motor symptoms due to destruction of the myelin sheat secondary to an auto-immune attack. A quarter to a third of patients do not respond to immunomodulatory first line recommended therapies. No second line treatment has shown its effectiveness with a sufficient level of evidence. Autologous hematopoietic stem cell transplantation (AHSCT) is a promising therapy for autoimmune disease, especially for CIDP in recent works. We present in this article an update on the diagnosis of CIDP, its conventional treatments as well as the results of AHSCT in this indication, which was the subject of French recommendations under the aegis of the SFGMTC and neuromuscular disease french faculty (FILNEMUS) as a third line therapy after failure of two first-line and one second-line treatments.

Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Its Variants

PURPOSE OF REVIEW

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and its variants comprise a group of immune-mediated neuropathies with distinctive clinical presentations and electrodiagnostic features. Prompt recognition of these treatable disorders is mandatory as delays result in significant disability and morbidity. This article highlights the clinical presentation, pathophysiology, diagnostic evaluation, and treatment approach of these polyneuropathies.

RECENT FINDINGS

The spectrum of CIDP is expanding with the recent characterization of neuropathies associated with nodal and paranodal antibodies. These neuropathies are distinguished by their unique presentations and are often refractory to IV immunoglobulin (IVIg) therapy. Subcutaneous immunoglobulins have recently been approved as a treatment option for CIDP and join corticosteroids, IVIg, and plasma exchange as first-line treatment.

SUMMARY

CIDP is characterized by progressive symmetric proximal and distal weakness, large fiber sensory loss, and areflexia, with clinical nadir reached more than 8 weeks after symptom onset. Autoimmune demyelinating neuropathies fall on a continuum, with differences in the type of nerve fibers affected and pattern of deficits. Distinguishing between typical CIDP and its variants allows for selection of the most appropriate treatment.

Therapeutic Plasma Exchange as a Treatment for Autoimmune Neurological Disease

Introduction

Therapeutic plasma exchange (TPE) is commonly used as treatment of certain autoimmune neurological diseases (ANDs), and its main objective is the removal of pathogenic autoantibodies. Our aim was to describe the clinical profile and the experience with the usage of TPE in patients with ANDs at our institution.

Methods

This is an observational retrospective study, including medical records of patients with diagnosis of ANDs who received TPE, between 2011 and 2018. Characteristics of TPE, such as number of cycles, type of replacement solution, and adverse effects, were evaluated. The modified Rankin Scale (mRS) was applied to measure the clinical response after the therapy.

Results

187 patients were included with the following diagnoses: myasthenia gravis (MG), n = 70 (37%); Guillain–Barré syndrome (GBS), n = 53 (28.3%), neuromyelitis optica spectrum disorders (NMOSD), n = 35 (18.7%); chronic inflammatory demyelinating polyneuropathy (CIDP), n = 23 (12.2%); and autoimmune encephalitis (AE), n = 6 (3.2%). The most used types of replacement solution were albumin (n = 131, 70%) and succinylated gelatin (n = 45, 24%). All patients received a median of five cycles (IQR 5-5). Hypotension and hydroelectrolytic disorders were the main complications. After TPE, 99 patients (52.9%) showed improvement in the mRS scores and a statistical significance (p < 0.05) was seen between the admission score and after TPE for every diagnosis except for CIDP.

Conclusion

TPE has an adequate safety profile, and improvement in functionality in treated patients reflects its effectiveness.

Electrodiagnostic data-driven clustering identifies a prognostically different subgroup of patients with chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

This study aimed to explore the correlations between electrodiagnostic (EDX) features in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and to investigate whether EDX data-driven clustering can identify a distinct subgroup regarding clinical phenotype and treatment response.

METHODS

We reviewed clinical and EDX data of 56 patients with definite CIDP fulfilling the 2010 European Federation of Neurological Societies and Peripheral Nerve Society criteria at two teaching hospitals. A hierarchical agglomerative clustering algorithm with complete linkage was used to partition the patients into subgroups with similar EDX features. A stepwise logistic regression analysis was performed to evaluate predictors of the long-term outcome.

RESULTS

EDX data-driven clustering partitioned the patients into two clusters, identifying a distinct subgroup characterised by coexistence of prominent conduction slowing and markedly reduced distally evoked compound muscle action potential (CMAP) amplitudes. This cluster of patients was significantly over-represented by an atypical subtype (distal acquired demyelinating symmetric polyneuropathy) compared with the other cluster (70% vs 26.1%, p=0.042). Furthermore, patients in this cluster invariably showed favourable long-term treatment outcome (100% vs 63%, p=0.023). In logistic regression analyses, the initial disability (OR 6.1, 95% CI 2.4 to 25.4), F-wave latency (OR 0.93, 95% CI 0.86 to 0.98) and distal CMAP duration (OR 0.96, 95% CI 0.91 to 0.99) were significant predictors of the poor long-term outcome.

CONCLUSION

Our results show that EDX data-driven clustering could differentiate a pattern of EDX features with prognostic implication in patients with CIDP. Reduced distally evoked CMAPs may not necessarily predict poor responses to treatment, and active treatment is warranted when prominent slowing of conduction is accompanied in the distal segments.

Measuring disease activity and predicting response to intravenous immunoglobulin in chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is characterised by significant clinical heterogeneity and as such reliable biomarkers are required to measure disease activity and assess treatment response. Recent advances in our understanding of disease pathogenesis and the discovery of novel serum-based, electrophysiologic and imaging biomarkers allow clinicians to make more informed decisions regarding individualised treatment regimes.

As a chronic immune-mediated process typified by relapse following withdrawal of immunomodulatory therapy, a substantial proportion of patients with CIDP require long term treatment with intravenous immunoglobulin (IVIg), a scarce and expensive donor-derived resource. The required duration and intensity of immunoglobulin treatment vary widely between individuals, highlighting both the heterogeneous nature of the underlying disease process as well as the variable pharmacologic properties of IVIg.

This review outlines the use of multimodal biomarkers in the longitudinal evaluation of nerve injury and how recent developments have impacted our ability to predict both response to immunoglobulin administration and its withdrawal.