Classifications and treatment responses in chronic immune-mediated demyelinating polyneuropathy

Characteristics and outcome of chronic inflammatory demyelinating polyradiculoneuropathy patients according to their diagnostic certainty based on the 2021 EAN/PNS criteria

INTRODUCTION

To describe the clinical characteristics and long term outcome of CIDP patients according to 2021 EAN/PNS diagnostic certainty categories.

METHODS

We reviewed clinical data, response to treatment, cerebrospinal fluid examination, and nerve conduction studies parameters of 39 adult "CIDP" and 24 "possible CIDP" patients. Data were collected at diagnosis and after one (T1), two (T2), three (T3) and five years (T5).

RESULTS

At diagnosis, "possible CIDP" patients' phenotypes were more atypical (especially focal/multifocal, p < .01) and "CIDP" patients had a higher NIS and INCAT scores (p = .08 and 0.08). Compared to baseline: median NIS score decreased in "CIDP" and was stable in "possible CIDP" patients at T1 (p < .05), T2 (p < .05) and T3 (p < .01); median MRC score slightly increased in "CIDP" and was stable in "possible CIDP" patients at T2 (p < .05); and INCAT disability scale slightly decreased in "CIDP" and was stable in "possible CIDP" patients at T3 (p < .05). The proportion of moderate to severely disabled (mRS > 2) patients in "possible CIDP" group was higher than in "CIDP" group (not significant). "CIDP" patients had a better objective response to immunotherapy (59 % responders) than "possible CIDP" patients (29 % responders, p < .05), especially among typical CIDP patients (86 % of responders in "CIDP" versus 33 % of responders in "possible CIDP" patients, p < .05).

CONCLUSION

"CIDP" patients had a more severe neuropathy, estimated with the NIS and INCAT scores, and "possible CIDP" patients had a more atypical phenotype at baseline. Our data suggest that long-term patient outcome and response to immunotherapy is better in "CIDP" than "possible CIDP".

Tips in navigating the diagnostic complexities of chronic inflammatory demyelinating polyradiculoneuropathy

The 2021 guideline of the European Academy of Neurology/Peripheral Nerve Society on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) includes important revisions to the previous 2010 guideline. This article highlights the new criteria and recommendations for the differential diagnosis of CIDP. In the revised guideline, the CIDP spectrum has been modified to include typical CIDP and four well-characterized CIDP variants, namely distal, multifocal/focal, motor and sensory CIDP, replacing the term 'atypical' CIDP. To improve the diagnosis of CIDP, the revised guideline attempts to improve the specificity of the diagnostic criteria for typical CIDP and the four CIDP variants. Specific clinical and electrodiagnostic (including both motor and sensory conduction) criteria are provided for typical CIDP and each of the CIDP variants. The levels of diagnostic certainty have been changed to CIDP and possible CIDP, with the removal of probable CIDP (due to the lack of difference in the accuracy of the electrodiagnostic criteria for probable CIDP) and definite CIDP (due to the lack of a gold standard for diagnosis). If the clinical and electrodiagnostic criteria allow only for a diagnosis of possible CIDP, cerebrospinal fluid analysis, nerve ultrasound, nerve magnetic resonance imaging, objective treatment response, and nerve biopsy can be used as supportive criteria to upgrade the diagnosis to CIDP. Although the revised guideline needs to be validated and its strengths and weaknesses assessed, using the guideline will likely improve the accuracy of diagnosis of CIDP and variants of CIDP, and aid in distinguishing CIDP from conditions with similar features.

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.

Application of the 2021 EAN/PNS criteria for chronic inflammatory demyelinating polyneuropathy

BACKGROUND

The diagnostic value of new criteria of the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) for chronic inflammatory demyelinating polyneuropathy (CIDP) is unknown.

METHODS

We performed a retrospective study of fulfilment of EAN/PNS 2021 criteria on 120 consecutive patients with a clinical diagnosis of 'suspected CIDP' and objective treatment response, attending University Hospitals Birmingham, UK. Specificity was evaluated versus 100 consecutive controls.

RESULTS

The sensitivity of EAN/PNS criteria for 'CIDP' was 83.3%. The sensitivity for 'CIDP' or 'possible CIDP' was 93.3%. Specificity was of 94% for 'CIDP' and 79% for 'CIDP' or 'possible CIDP'. No sensitivity/specificity differences were ascertained with previous versions ('CIDP': sensitivity: 83.3% vs 81.3%, p=0.74, specificity: 94% vs 96.1%, p=0.38, respectively; 'CIDP' or 'possible CIDP': sensitivity: 93.3% vs 96.7%, p=0.25 and specificity: 79% vs 69.2 %, p=0.09, respectively). F-wave prolongation, proximal and distal temporal dispersion were the most likely parameters to contribute to false positives, whereas distal motor latency was the least likely. No impact of sensory electrophysiology could be ascertained. 'Typical CIDP' represented 79% of the CIDP cohort. The largest component of the 'variant CIDP' group was represented by focal/multifocal forms (14%). With new criteria, 6.7% of the cohort did not meet requirements, among whom the majority (75%) had paranodopathy or chronic immune sensory polyradiculopathy (CISP).

DISCUSSION

The sensitivity and specificity of new EAN/PNS criteria for CIDP is equivalent to that of previous versions. The exclusion of paranodopathies and CISP from the CIDP spectrum impacts on management of a non-negligible proportion of treatment-responsive patients.

Relevance of Nerve Biopsy in the Diagnosis of Chronic Inflammatory Demyelinating Polyneuropathy—A Systematic Review

Chronic Inflammatory Demyelinating Polyneuropathy is an immune-mediated pathology of the peripheral nerves and nerve roots that leads to weakness and sensory symptoms. Given its clinical heterogeneity, often times diagnosis is challenging. Even though nerve conduction studies and clinical features are the main criteria used for diagnosis, supplementary investigations, such as nerve biopsies, cerebral spinal fluid examination and magnetic resonance studies, may be used in order to confirm the diagnosis. Given the fact that the hallmark in CIDP physiopathology is the demyelination process, nerve biopsies are used to demonstrate and assess the magnitude of the phenomenon. The question and the main interest of this review is whether histopathological findings are relevant for the diagnosis and can be useful in disease assessment.

Usefulness and prognostic value of diagnostic tests in patients with possible chronic inflammatory demyelinating polyradiculoneuropathy

INTRODUCTION/AIMS

Recent guidelines define chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and possible CIDP. The aims of our study were to evaluate the value of diagnostic tests to support the diagnosis of CIDP in patients with possible CIDP and to identify prognostic factors of therapeutic success.

METHODS

We conducted an observational retrospective two-center study between 2014 and 2019. We selected patients with a clinical presentation suggesting CIDP, but whose electrodiagnostic (EDX) test results did not meet the EFNS/PNS 2021 criteria. We analyzed epidemiologic and clinical features, axonal loss on EDX, cerebrospinal fluid (CSF), somatosensory evoked potentials (SSEPs), plexus magnetic resonance imaging (MRI), nerve biopsy, and therapeutic response.

RESULTS

We selected 75 patients, among whom 30 (40%) responded to treatment. The positivity rates of CSF analysis, MRI and SSEPs were not influenced by the clinical presentation or by the delay between symptom onset and medical assessment. A high protein level in CSF, female gender, and a relapsing-remitting course predicted the therapeutic response.

DISCUSSION

It is important to properly diagnose suspected CIDP not meeting EFNS/PNS 2021 EDX criteria by using supportive criteria. Specific epidemiological factors and a raised CSF protein level predict a response to treatment. Further prospective studies are needed to improve diagnosis and the prognostic value of diagnostic tests in CIDP.

Contemporary challenges in the diagnosis and management of chronic inflammatory demyelinating polyneuropathy

INTRODUCTION

Despite extensive research, multiple inter-related diagnostic and management challenges remain for chronic inflammatory demyelinating polyneuropathy (CIDP).

AREAS COVERED

A literature review was performed on diagnosis and treatment in CIDP. The clinical features and disease course were evaluated. Investigative techniques, including electrophysiology, cerebrospinal fluid examination, neuropathology, imaging and neuroimmunology, were considered in relation to technical aspects, sensitivity, specificity, availability and cost. Available evidenced-based treatments and those with possible efficacy despite lack of evidence, were considered, as well as current methods for evaluation of treatment effects.

EXPERT OPINION

CIDP remains a clinical diagnosis, supported first and foremost by electrophysiology. Other investigative techniques have limited impact. Most patients with CIDP respond to available first-line treatments and immunosuppression may be efficacious in those who do not. Consideration of the natural history and of the high reported remission rate, of under-recognised associated disabling features, of treatment administration modalities and assessment methods, require enhanced attention.

European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision

OBJECTIVE

To revise the 2010 consensus guideline on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Seventeen disease experts, a patient representative, and two Cochrane methodologists constructed 12 Population/Intervention/Comparison/Outcome (PICO) questions regarding diagnosis and treatment to guide the literature search. Data were extracted and summarized in GRADE summary of findings (for treatment PICOs) or evidence tables (for diagnostic PICOs).

RESULTS

Statements were prepared according to the GRADE Evidence-to-Decision frameworks. Typical CIDP and CIDP variants were distinguished. The previous term "atypical CIDP" was replaced by "CIDP variants" because these are well characterized entities (multifocal, focal, distal, motor, or sensory CIDP). The levels of diagnostic certainty were reduced from three (definite, probable, possible CIDP) to only two (CIDP and possible CIDP), because the diagnostic accuracy of criteria for probable and definite CIDP did not significantly differ. Good Practice Points were formulated for supportive criteria and investigations to be considered to diagnose CIDP. The principal treatment recommendations were: (a) intravenous immunoglobulin (IVIg) or corticosteroids are strongly recommended as initial treatment in typical CIDP and CIDP variants; (b) plasma exchange is strongly recommended if IVIg and corticosteroids are ineffective; (c) IVIg should be considered as first-line treatment in motor CIDP (Good Practice Point); (d) for maintenance treatment, IVIg, subcutaneous immunoglobulin or corticosteroids are recommended; (e) if the maintenance dose of any of these is high, consider either combination treatments or adding an immunosuppressant or immunomodulatory drug (Good Practice Point); and (f) if pain is present, consider drugs against neuropathic pain and multidisciplinary management (Good Practice Point).

European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision

To revise the 2010 consensus guideline on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Seventeen disease experts, a patient representative, and two Cochrane methodologists constructed 12 Population/Intervention/Comparison/Outcome (PICO) questions regarding diagnosis and treatment to guide the literature search. Data were extracted and summarized in GRADE summary of findings (for treatment PICOs) or evidence tables (for diagnostic PICOs). Statements were prepared according to the GRADE Evidence-to-Decision frameworks. Typical CIDP and CIDP variants were distinguished. The previous term "atypical CIDP" was replaced by "CIDP variants" because these are well characterized entities (multifocal, focal, distal, motor, or sensory CIDP). The levels of diagnostic certainty were reduced from three (definite, probable, possible CIDP) to only two (CIDP and possible CIDP), because the diagnostic accuracy of criteria for probable and definite CIDP did not significantly differ. Good Practice Points were formulated for supportive criteria and investigations to be considered to diagnose CIDP. The principal treatment recommendations were: (a) intravenous immunoglobulin (IVIg) or corticosteroids are strongly recommended as initial treatment in typical CIDP and CIDP variants; (b) plasma exchange is strongly recommended if IVIg and corticosteroids are ineffective; (c) IVIg should be considered as first-line treatment in motor CIDP (Good Practice Point); (d) for maintenance treatment, IVIg, subcutaneous immunoglobulin or corticosteroids are recommended; (e) if the maintenance dose of any of these is high, consider either combination treatments or adding an immunosuppressant or immunomodulatory drug (Good Practice Point); and (f) if pain is present, consider drugs against neuropathic pain and multidisciplinary management (Good Practice Point).

CIDP mimics: a case series

Background

To report our experience with a group of patients referred for refractory CIDP who fulfilled “definite” electrodiagnostic EFNS criteria for CIDP but were found to have an alternate diagnosis.

Methods

Patients who were seen between 2017 and 2019 for refractory CIDP that fulfilled “definite” electrodiagnostic ENFS criteria for CIDP, but had an alternate diagnosis, were included. Patients who correctly had CIDP, anti MAG neuropathy, or MMN with conduction block, were excluded from the study. Demographics, clinical and electrophysiological characteristics, pertinent workup, final alternate diagnoses, and outcomes were collected.

Results

Seven patients were included: POEMS (n = 5), CANOMAD (n = 1), and neurolymphomatosis (n = 1). Most patients reported neuropathic pain and leg swelling (n = 6) or significant weight loss (n = 4). All patients had a monoclonal protein, and most patients who were tested had an elevated VEGF and CSF cyto-albuminologic dissociation. Electrophysiology showed pronounced intermediate more than distal demyelination, and axonal loss in the lower extremities. Response to steroids or IVIG varied, but some patients did respond to these treatments, especially early in the disease.

Conclusion

Pain, systemic symptoms, suggestive electrophysiological findings, and/or a serum monoclonal protein should raise suspicion for CIDP mimics. Initial response to steroids or IVIG, over reliance on CSF, and electrophysiology findings can all be misleading.

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.

Incidence and Prevalence of Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A Systematic Review and Meta-Analysis

BACKGROUND

Prevalence and incidence rates of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) are required to determine the impact of CIDP on society. We aimed to estimate the prevalence and incidence of CIDP worldwide and to determine the effect of diagnostic criteria on prevalence and incidence.

METHOD

A systematic review was conducted for all published incidence and prevalence studies on CIDP until May 18, 2017. Methodological quality was assessed using the Methodological Evaluation of Observational Research checklist. We performed a random effect meta-analysis to estimate pooled prevalence and incidence rates.

RESULTS

Of the 907 studies, 11 were included in the systematic review, 5 in the meta-analysis of incidence (818 cases; 220,513,514 person-years) and 9 in the meta-analysis of prevalence (3,160 cases; 160,765,325 population). These studies had a moderate quality. The pooled crude incidence rate was 0.33 per 100,000 person-years (95% CI 0.21-0.53; I2 = 95.7%) and the pooled prevalence rate was 2.81 per 100,000 (95% CI 1.58-4.39; I2 = 99.1%). Substantial heterogeneity in incidence and prevalence across studies seems to be partly explained by using different diagnostic criteria.

CONCLUSION

These findings provide a starting point to estimate the social burden of CIDP and demonstrate the need to reach consensus on diagnostic criteria for CIDP.

Immune-mediated neuropathies

Since the discovery of an acute monophasic paralysis, later coined Guillain-Barré syndrome, almost 100 years ago, and the discovery of chronic, steroid-responsive polyneuropathy 50 years ago, the spectrum of immune-mediated polyneuropathies has broadened, with various subtypes continuing to be identified, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). In general, these disorders are speculated to be caused by autoimmunity to proteins located at the node of Ranvier or components of myelin of peripheral nerves, although disease-associated autoantibodies have not been identified for all disorders. Owing to the numerous subtypes of the immune-mediated neuropathies, making the right diagnosis in daily clinical practice is complicated. Moreover, treating these disorders, particularly their chronic variants, such as CIDP and MMN, poses a challenge. In general, management of these disorders includes immunotherapies, such as corticosteroids, intravenous immunoglobulin or plasma exchange. Improvements in clinical criteria and the emergence of more disease-specific immunotherapies should broaden the therapeutic options for these disabling diseases.

Costs of illness in chronic inflammatory demyelinating polyneuropathy in Germany

INTRODUCTION

Cost of illness studies are essential to estimate societal costs of chronic inflammatory demyelinating polyneuropathy (CIDP) and identify cost-driving factors.

METHODS

In total, 108 patients were recruited from 3 specialized neuroimmunological clinics. Costs were calculated for a 3-month period, including direct and indirect costs. The following outcomes were assessed: inflammatory neuropathy cause and treatment disability scale, Mini-Mental State Examination, Beck Depression Inventory, Charlson comorbidity index, EuroQol-5D, World Health Organization quality of life instrument, and socioeconomic status. Univariate and multivariate analyses were applied to identify cost-driving factors.

RESULTS

Total quarterly costs were €11,333. Direct costs contributed to 83% of total costs (€9,423), whereas indirect costs accounted for 17% (€1,910) of total costs. The cost of intravenous immunoglobulin (IVIg) was the main determinant of total costs (67%). Reduced health-related quality of life and depressive symptoms were identified as independent predictors of higher total costs.

DISCUSSION

CIDP is associated with high societal costs, mainly resulting from the cost of IVIg treatment. Muscle Nerve 58: 681-687, 2018.

Immune-mediated Neuropathies Our Experience over 3 Years

Introduction

Immune-mediated peripheral neuropathy is the term applied to a spectrum of peripheral nerve disorders where immune dysregulation plays a role. Therefore, they are treatable. We analyzed the cases seen in the past 3 years by us and evaluated the clinical, laboratory, and outcome parameters in these patients.

Patients and Methods

Consecutive patients seen by the authors and diagnosed as immune-mediated neuropathy were analyzed for etiology, pathology, and outcome assessed.

Results

A total of sixty patients, 31 acute and 29 chronic neuropathies, were identified. Their subtypes treatment and outcome assessed. Males were significantly more in both acute and chronic cases. Miller Fisher 4, AMAN 1, paraplegic type 1, motor dominant type 19, Sensory-motor 1, MADSAM 3, Bifacial 2. Nonsystemic vasculitis was seen in 16 out of 29 chronic neuropathy and HIV, POEMS, and diabetes mellitus one each.

Discussion

There is a spectrum of immune-mediated neuropathy which varies in clinical course, response to treatment, etc., Small percentage of uncommon cases are seen. In this group, mortality was nil and morbidity was minimal.

Conclusion

Immune-mediated neuropathies are treatable and hence should be diagnosed early for good quality outcome.

Intravenous immunoglobulin treatment in chronic inflammatory demyelinating polyradiculoneuropathy, a time to start and a time to stop

Intravenous immunoglobulin (IVIg) is often used as preferred treatment in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Several studies highlighted the short-term efficacy of IVIg for CIDP yet many patients need maintenance therapy. Notwithstanding the fact IVIg has been used for over 30 years in CIDP, there is only limited evidence to guide dosage and interval during maintenance treatment. The variation in disease course, lack of biomarkers, and fear of deterioration after stopping IVIg makes long-term treatment challenging. Recent studies suggest a proportion of patients receive unnecessary IVIg maintenance treatment. This review provides an overview of the use of IVIg for CIDP treatment, focusing on evidence for long-term IVIg use.

Early predictive factors of disability in CIDP

The objective of this study was to identify early clinical, biochemical and electrophysiological prognostic factors of disability in CIDP. We evaluated a dataset from 60 CIDP patients that included sex, age of onset, type of onset, phenotype, disease duration, response to treatment, disability at the time of diagnosis assessed using the modified Rankin Scale (baseline mRS), cerebrospinal fluid protein levels and electrophysiological data. All patients had clinical assessment of disability through the mRS within the last 6 months (last mRS) before enrollment in the study. Stepwise forward logistic regression model was applied to evaluate the impact of clinical, biochemical and electrophysiological parameters on the last mRS, considered as binary outcome (absence or presence of severe disability, i.e., <4/≥4 mRS). Moreover, we used Spearman's rank correlation coefficient to evaluate the relationship between disease duration and last mRS. We observed a significant relationship between last mRS and baseline mRS [p = 0.015, z = 2.44, OR 5.15 (CI 1.38-19.22)] and age of onset [p = 0.017, z = 2.39, OR 1.13 (CI 1.02-1.27) per additional year of age of onset]. There was no correlation between disease duration and last mRS. Our data suggest that a worse clinical status at the beginning of disease and an older age at onset may be negative prognostic factors of long-term disability independent from disease duration.

Sialylation of IgG Fc domain impairs complement-dependent cytotoxicity

IgG molecules exert both pro- and antiinflammatory effector functions based on the composition of the fragment crystallizable (Fc) domain glycan. Sialylated IgG Fc domains have antiinflammatory properties that are attributed to their ability to increase the activation threshold of innate effector cells to immune complexes by stimulating the upregulation of the inhibitory Fcγ receptor IIB (FcγRIIB). Here, we report that IgG Fc sialylation of human monoclonal IgG1 molecules impairs their efficacy to induce complement-mediated cytotoxicity (CDC). Fc sialylation of a CD20-targeting antibody had no impact on antibody-dependent cellular cytotoxicity and did not change the affinity of the antibody for activating Fcγ receptors. In contrast, the presence of sialic acid abrogated the increased binding of C1q to Fc-galactosylated IgG1 and resulted in decreased levels of C3b deposition on the cell surface. Similar to monoclonal antibodies, sialic acid inhibited the increased C1q binding to galactosylated Fc fragments in human polyclonal IgG. In sera derived from patients with chronic inflammatory demyelinating polyneuropathy, an autoimmune disease of the peripheral nervous system in which humoral immune responses mediate tissue damage, induction of IgG Fc sialylation was associated with clinical disease remission. Thus, impairment of CDC represents an FcγR-independent mechanism by which Fc-sialylated glycovariants might limit proinflammatory IgG effector functions.

Deregulated Fcγ receptor expression in patients with CIDP

Objective:

To evaluate the expression of activating and inhibitory Fc-gamma receptors (FcγRs) before and during clinically effective therapy with IV immunoglobulin (IVIg) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

Methods:

Peripheral blood leukocyte subsets, including classical CD14^highCD16⁻ and nonclassical inflammatory CD14^lowCD16⁺ monocytes as well as naive CD19⁺CD27⁻ and memory CD19⁺CD27⁺ B cells, were obtained at baseline and monitored at 2 and 4–8 weeks after initiation of IVIg therapy.

Results:

Compared with healthy donors matched by age and sex, patients with CIDP showed increased expression levels of the activating high-affinity FcγR1 on CD14^highCD16⁻ (p < 0.001) and CD14^lowCD16⁺ monocytes (p < 0.001). Expression of the activating low-affinity FcγRIIA was increased on CD14^lowCD16⁺ monocytes (p = 0.023). Conversely, expression of the inhibitory FcγRIIB was reduced on naive (p = 0.009) and memory (p = 0.002) B cells as well as on CD14^highCD16⁻ monocytes (p = 0.046). Clinically effective IVIg therapy partially restored deregulated FcγR expression on B cell subsets and monocytes.

Conclusions:

The FcγR regulatory system is disturbed in patients with CIDP. Balancing activating vs inhibitory FcγR expression might provide a clinical benefit for patients with CIDP.

Acquired immune demyelinating neuropathies

PURPOSE OF REVIEW

Acquired immune demyelinating neuropathies refer to a group of disorders that share overlapping sensory, motor, and autonomic clinical, laboratory, and electrodiagnostic features. It is important to recognize acquired immune demyelinating neuropathies as they are generally responsive to immunosuppressive or immunomodulatory therapies.

RECENT FINDINGS

This article reviews recently developed early prognostic tools in Guillain-Barré syndrome and discusses the evolving understanding of chronic demyelinating phenotypes with differing treatment responsiveness.

SUMMARY

While weakness and numbness progress over 2 to 4 weeks in Guillain-Barré syndrome, they continue to evolve beyond 8 weeks in chronic inflammatory demyelinating polyradiculoneuropathy and over 4 to 8 weeks in subacute inflammatory demyelinating polyradiculoneuropathy. Acquired immune demyelinating neuropathies present uncommonly as variants with predominance of ocular, bulbar, sensory, autonomic, or motor manifestations in addition to regional variants, such as paraparetic acquired immune demyelinating neuropathies. Establishing the correct diagnosis is important as these immune disorders differ in response to corticosteroids and other immunosuppressive therapies.

MRI of the cervical nerve roots in the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy: a single-institution, retrospective case-control study

OBJECTIVE

To systematically evaluate the usefulness of assessing the cervical nerve roots by MRI for the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

DESIGN

Single-institution, retrospective case-control study.

SETTING

A regional referral hospital.

PARTICIPANTS

We retrospectively enrolled 15 consecutive patients with CIDP who satisfied the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) typical and definite criteria and underwent cervical MRI. 30 control patients who had also undergone cervical MRI were included, matched with regard to sex, age and MRI system. The diagnoses of the control patients included cervical spondylosis (n=19), cervical spine trauma (n=2), infection (n=1), malignancies (n=4), demyelinating disorders (n=2) and neurodegenerative disorders (n=2).

MEASUREMENT

A radiologist determined the C5-C8 root diameters on the coronal short tau inversion recovery (STIR) images. Signal intensities of these roots were quantified as nerve-to-muscle contrast-to-noise ratios (CNRs), which were calculated using mean signal intensities of the roots and sternocleidomastoid muscle as well as SD of background noise. Statistical analyses were performed to determine the diagnostic accuracy of the diameters and nerve-to-muscle CNRs. Another radiologist reviewed MRI for ensuring reproducibility.

RESULTS

The root diameters showed no significant differences between the patients with CIDP and control patients. The nerve-to-muscle CNRs were significantly higher in the patients with CIDP. We defined the sum of nerve-to-muscle CNRs of C5-C8 roots as the CNR score to serve as an index of overall signal intensity. The area under the receiver operating characteristic curve of CNR scores was 0.731. The reproducibility of the assessment procedure was satisfactory.

CONCLUSIONS

Our results suggest that assessment of the cervical nerve roots by MRI is useful for CIDP diagnosis when the signal intensities, rather than the diameters, are paid more attention on STIR images.

Neuro-ophthalmological Complications of Chronic Inflammatory Demyelinating Polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) can lead to prominent nerve hypertrophy, which can mimic other forms of neuropathy radiologically. Neuro-ophthalmological complications can also occur in CIDP, either at presentation or chronically in the disorder. This can also cause diagnostic difficulties. We report three cases of neuro-ophthalmological complications of CIDP: two cases of papilloedema and one case of proptosis. In all three cases cranial nerve hypertrophy was present. CIDP should be considered in neuro-ophthalmological presentations associated with cranial/spinal nerve root hypertrophy.

Chronic inflammatory demyelinating polyradiculoneuropathy: from bench to bedside

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common treatable chronic autoimmune neuropathy. Multiple diagnostic criteria have been established, with the primary goal of identifying neurophysiologic hallmarks of acquired demyelination. Treatment modalities have expanded to include numerous immunomodulatory therapies, although the best evidence continues to be for corticosteroids, plasma exchange, and intravenous immunoglobulin (IVIg). This review describes the pathology, epidemiology, pathogenesis, diagnosis, and treatment of CIDP.

Expression and function of the inhibitory Fcγ-receptor in CIDP

The inhibitory Fc-gamma receptor (FcγR) IIB, expressed on myeloid and B cells, has a critical role in the balance of tolerance and auto-immunity, and is required for the anti-inflammatory activity of intravenous immunoglobulin (IVIg) in various murine disease models. We found that treatment-naÏve patients with chronic inflammatory demyelinating polyneuropathy (CIDP) showed an impaired expression of FcγIIB levels on naÏve B cells, and failed to upregulate or to maintain upregulation of FcγIIB, as B cells progressed from the naÏve to the memory compartment. The impaired expression of FcγRIIB was, at least partially, restored by clinically effective IVIg treatment. It remains to be determined whether FcγRIIB expression is a candidate for pre-treatment assessment and might thus be used as a prognostic marker of treatment response to IVIg. Nonetheless, our data suggest that new strategies specifically targeting FcγRIIB expression might have therapeutic merit in CIDP.

[Administration of intravenous immunoglobulins in neurology. An evidence-based consensus: update 2010]

Our knowledge on the clinical efficacy of intravenous immunoglobulins (IVIg) in neurological diseases has greatly increased in the last 5 years. Liquid formulations with a higher concentration of IVIg have simplified administration. Despite a worldwide increase in plasma production it is still a valuable biological product which is why current indications must be continuously validated. Long-term efficacy of the preparation Gamunex could be demonstrated in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). In acute myasthenic worsening a dose of 1 g IVIg/kg body weight appears to be sufficient for clinical stabilization. New indications, such as the postpolio syndrome or Alzheimer's disease are being explored in clinical trials. In addition to the consensus statement from 2004 the evidence for clinical use of IVIg has been re-evaluated and recommendations are given.

Pathogenesis and treatment of immune-mediated neuropathies

Immune-mediated neuropathies represent a heterogeneous spectrum of peripheral nerve disorders that can be classified according to time course, predominant involvement of motor/sensory fibers, distribution of deficits and paraclinical parameters such as electrophysiology and serum antibodies. In the last few years, significant advances have been achieved in elucidating underlying pathomechanisms, which made it possible to identify potential therapeutic targets. In this review, we discuss the latest development in pathogenesis and treatment of immune-mediated neuropathies.

Chronic inflammatory demyelinating polyradiculoneuropathy: diagnostic and therapeutic challenges for a treatable condition

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic neuropathy of supposed immune origin. Understanding of its pathophysiology has recently improved, although its causes remain unclear. The classic presentation of CIDP includes sensory and motor symptoms in the distal and proximal segments of the four limbs with areflexia, evolving over more than 8 weeks. Raised protein concentrations in CSF and heterogeneous slowing of nerve conduction are typical of the condition. In addition to this usual phenotype, distribution of symptoms, disease course, and disability can be heterogeneous, leading to underdiagnosis of the disorder. Diagnosis is sometimes challenging and can require use of imaging and nerve biopsy. Steroids and intravenous immunoglobulin are effective, and plasma exchange can be helpful as rescue therapy. The usefulness of immunosuppressants needs to be established. The identification of specific diagnostic markers and new therapeutic strategies with conventional or targeted immunotherapy are needed to improve the outlook for patients with CIDP.

Impaired inhibitory Fcgamma receptor IIB expression on B cells in chronic inflammatory demyelinating polyneuropathy

The inhibitory Fc-gamma receptor FcgammaRIIB, expressed on myeloid and B cells, has a critical role in the balance of tolerance and autoimmunity, and is required for the antiinflammatory activity of intravenous Ig (IVIG) in various murine disease models. However, the function of FcgammaRIIB and its regulation by IVIG in human autoimmune diseases are less well understood. Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common treatable acquired chronic polyneuropathy, and IVIG is widely used as a first-line initial and maintenance treatment. We found that untreated patients with CIDP, compared with demographically matched healthy controls, showed consistently lower FcgammaRIIB expression levels on naive B cells, and failed to up-regulate or to maintain up-regulation of FcgammaRIIB as B cells progressed from the naive to the memory compartment. Concomitantly, the rare -386C/-120A FcgammaRIIB promoter polymorphism resulting in reduced promoter activity previously associated with autoimmune phenotypes was overrepresented in CIDP. Also, FcgammaRIIB protein expression was up-regulated on monocytes and B cells after clinically effective IVIG therapy. Thus, our results suggest that the inhibitory FcgammaRIIB is impaired at a critical B cell differentiation checkpoint in CIDP, and that modulating FcgammaRIIB expression might be a promising approach to efficiently limit antibody-mediated immunopathology in CIDP.

Diagnosis and treatment in inflammatory neuropathies

The inflammatory neuropathies are a large diverse group of immune-mediated neuropathies that are amenable to treatment and may be reversible. Their accurate diagnosis is essential for informing the patient of the likely course and prognosis of the disease, informing the treating physician of the appropriate therapy and informing the scientific community of the results of well-targeted, designed and performed clinical trials. With the advent of biological therapies able to manipulate the immune response more specifically, an understanding of the pathogenesis of these conditions is increasingly important. This review presents a broad overview of the pathogenesis, diagnosis and therapy of inflammatory neuropathies, concentrating on the most commonly encountered conditions.