Monitoring Clinical Course and Treatment Response in Chronic Inflammatory Demyelinating Polyneuropathy During Routine Care: A Review of Clinical and Laboratory Assessment Measures

Usefulness of serum neurofilament light chain in chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

The development of new biomarkers is essential to improve diagnostic accuracy and guide treatment decisions in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The aim of this study was to investigate the utility of the serum neurofilament light chain (sNfL) level as a marker for disability and response to immunomodulatory treatment in patients with CIDP.

METHODS

This prospective, single-center, observational study included 38 patients with CIDP: 19 treatment-naive (CIDP-I) patients assessed before and after the initiation of immunomodulatory therapy and 19 stable patients on maintenance immunoglobulins (CIDP-M). Clinical scales (INCAT, I-RODS, MRC-SS and grip strength) were used to assess disability and treatment response. Nerve conduction study data were collected.

RESULTS

The median sNfL level (pg/mL) was greater in CIDP-I patients than in CIDP-M patients (23.4 vs. 7.7; p = 0.002). A reduction in sNfL levels was observed in CIDP-I patients after 5 months of immunomodulatory treatment (23.4 vs. 15.0; p = 0.001). sNfL levels were correlated with greater disability as assessed by the INCAT (p = 0.007), I-RODS (p = 0.004), and MRC-SS (p = 0.016) in treatment-naive patients but not in those receiving maintenance therapy. sNfL levels correlated with the average amplitude of the distal compound muscle action potential of the median, ulnar, peroneal and tibial nerves from the most affected limb (p = 0.043).

CONCLUSIONS

sNfL levels are significantly reduced in patients with CIDP who respond to immunomodulatory treatment and are positively correlated with disability. These findings highlight the utility of sNfL as a marker of disease activity and treatment response in patients with CIDP.

Long-Term Follow Up in Anti-Contactin-1 Autoimmune Nodopathy

OBJECTIVE

To analyze long-term clinical and biomarker features of anti-contactin-1 (CNTN1) autoimmune nodopathy (AN).

METHODS

Patients with anti-CNTN1+ autoimmune nodopathy detected in our laboratory from which clinical information was available were included. Clinical features and treatment response were retrospectively collected. Autoantibody, serum neurofilament light chain (sNfL), and serum CNTN1 levels (sCNTN1) were analyzed at baseline and follow up.

RESULTS

A total of 31 patients were included. Patients presented with progressive sensory motor neuropathy (76.7%) with proximal (74.2%) and distal involvement (87.1%), ataxia (71.4%), and severe disability (median INCAT at nadir of 8). A total of 11 patients (35%) showed kidney involvement. Most patients (97%) received intravenous immunoglobulin, but only 1 achieved remission with intravenous immunoglobulin. A total of 22 patients (71%) received corticosteroids, and 3 of them (14%) did not need further treatments. Rituximab was effective in 21 of 22 patients (95.5%), with most of them (72%) receiving a single course. Four patients (12.9%) relapsed after a median follow up of 25 months after effective treatment (12-48 months). Anti-CNTN1 titers correlated with clinical scales at sampling and were negative after treatment in all patients, but 1 (20/21). sNfL levels were significantly higher and sCNTN1 significantly lower in anti-CNTN1+ patients than in healthy controls (sNfL: 135.9 pg/ml vs 7.48 pg/ml, sCNTN1: 25.03 pg/ml vs 22,186 pg/ml, p < 0.0001). Both sNfL and sCNTN1 returned to normal levels after successful treatment.

INTERPRETATION

Patients with anti-CNTN1+ autoimmune nodopathy have a characteristic clinical profile. Clinical and immunological relapses are infrequent after successful treatment, suggesting that continuous treatment is unnecessary. Anti-CNTN1 antibodies, sNfL, and sCNTN1 levels are useful to monitor disease status in these patients. ANN NEUROL 2025;97:529-541.

Distinguishing Chronic Inflammatory Demyelinating Polyneuropathy From Mimic Disorders: The Role of Statistical Modeling

BACKGROUND AND AIMS

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is difficult to distinguish from mimicking disorders, with misdiagnosis resulting in IVIG overutilization. We evaluate a clinical-electrophysiological model to facilitate CIDP versus mimic neuropathy prediction.

METHODS

Using the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) 2021 CIDP guidelines we derived 26 clinical and 144 nerve conduction variables. The model was generated and validated utilizing total CIDP (n = 129) and mimics (n = 309); including (1) IgG4-nodopathies; (2) POEMS (polyneuropathy-organomegaly-endocrinopathy-monoclonal protein-skin changes); (3) anti-myelin-associated-glycoprotein; (4) paraneoplastic; (5) Waldenström B-cell lymphoma; (6) diabetic neuropathies; (7) amyloidosis; (8) Charcot-Marie-Tooth; (9) motor neuropathies/neuronopathies; and (10) idiopathic-inflammatory-myopathies.

RESULTS

We analyzed 9282 clinical and 51 408 electrophysiological data points. Univariate analysis identified 11 of 26 clinical variables with significant odds ratios. A multivariate regression model using four clinical and two electrophysiologic variables achieved 93% area-under-curve (95% CI 91-95): progression over 8 weeks (OR 40.66, 95% CI 5.31-311.36), absent autonomic involvement (OR 17.82, 95% CI 2.93-108.24), absent muscle atrophy (OR 16.65, 95% CI 3.27-84.73), proximal weakness (OR 3.63, 95% CI 1.58-8.33), ulnar motor conduction velocity slowing < 35.7 m/s (OR 5.21, 95% CI 2.13-12.76), and ulnar motor conduction block (OR 13.37, 95% CI 2.47-72.40). A web-based probability calculator (https://news.mayocliniclabs.com/cidp-calculator/) was developed, with 100% sensitivity and 68% specificity at a 92% probability threshold. Specificity improved to 93% when considering "red flags," electrophysiologic criteria, and laboratory testing.

INTERPRETATION

A probability calculator using clinical electrophysiological variables assists CIDP differentiation from mimics, with scores below 92% unlikely to have CIDP. The highest specificity is achieved by considering clinical "red flags," electrophysiologic demyelination, and laboratory testing.

Efficacy and safety of combined low-dose rituximab regimen for chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVE

To determine the efficacy and safety of combined low-dose rituximab with conventional therapy for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) treatment.

METHODS

Total 73 patients with CIDP were enrolled for the retrospective cohort study, and divided into conventional first-line therapy cohort (n = 40) and combined low-dose rituximab (100 mg per infusion) cohort (n = 33). The outcome measures include scores of I-RODS, mRS, INCAT, ONLS, TSS, and COMPASS 31 scale at baseline and regular four visits (4, 16, 28, and 52 weeks), as well as proportion of favorable response and outcome, corticosteroids dosage, and deterioration occurrence during follow-up.

RESULTS

Compared to conventional therapy cohort, combined rituximab cohort presented better improvements and higher proportion of favorable response in scales assessments at each visit, as well as significantly reduced corticosteroids dosage and deterioration occurrence during the follow-up. Analyses of subgroups showed better improvements in both typical CIDP and CIDP variants in combined rituximab cohort than those in conventional therapy cohort, but had no differences between each other. Early initiating combined rituximab regimen (<10 weeks) showed better improvements than delayed initiation (≥10 weeks) at the first three visits within 28 weeks, while had no difference in favorable prognoses at the last visit of 52 weeks after once reinfusion. No rituximab correlated serious adverse events were reported in our patients.

INTERPRETATION

Our simplified regimen of combined low-dose rituximab has been firstly demonstrated for the better efficacy and safety than conventional therapy in CIDP treatment.

Assessing hand motor function in chronic immune-mediated neuropathies: a proof-of-concept study using a data glove

BACKGROUND

Chronic immune-mediated neuropathies are clinically heterogeneous and require regular, objective, and multidimensional monitoring to individualize treatment. However, established outcome measures are insufficient regarding measurement quality criteria (e.g., reliability, objectivity) or functional relevance. Wearables such as data gloves might be helpful, allowing repeated quantification of complex everyday life-relevant motor function of the hand.

METHODS

25 patients with chronic inflammatory demyelinating polyneuropathy or multifocal motor neuropathy were followed-up at five time points during maintenance therapy with intravenous immunoglobulin. 14 of them showed clinically relevant hand motor impairment. We examined the patients' hand function using a data glove which quantifies the active range of motion (ROM) of the hand based on three different movement patterns. In addition, clinical outcome parameters (grip strength measurement, MRC Sum Score, INCAT disability score), nerve conduction studies (NCS), and high-resolution ultrasound (HRUS) were performed, and patient-reported outcome measures (PROMs) like the Rasch-built Overall Disability Scale (R-ODS) were assessed. We calculated correlation coefficients, performed Receiver Operating Characteristic analysis, as well as correlation analyses for the glove data and clinical outcome parameters. Longitudinal analyses were based on a Linear Mixed Model, and we assessed construct validity of the data glove by analyzing correlations between the glove measurements and well-established clinical parameters.

RESULTS

We found good to excellent test-retest reliability for the ROM in all glove movement patterns (Intraclass correlation coefficients = 0.83-0.94), underlining the ability to capture clinical stability. Moreover, the glove demonstrated adequate, sensitivity and specificity in detecting hand motor impairment (area under the curve (AUC): 0.714-0.780), and it performed better than NCS and HRUS (AUC: 0.552/0.701). The AUC values for the metrically scaled parameters include: Vigorimeter (AUC: 0.929) and R-ODS (AUC: 0.698). Additionally, the data glove proved to be a valid tool, as we demonstrated moderate to strong, significant correlations between the glove and established clinical parameters (especially Vigorimeter), as well as PROMs (especially R-ODS).

CONCLUSIONS

This data glove allowed for a non-invasive assessment of the hand motor function and yielded investigator-independent results that reliably reflected individual functional deficits with relevance to everyday life. Future studies should explore the ability to predict clinically meaningful responses to immunomodulatory treatment and to support and monitor rehabilitation progress, with potential applications in other neurological diseases as well. Trial registration at the German Clinical Trials Register, Deutsches Register Klinischer Studien (DRKS: 00027345), retrospectively registered on 23rd March 2022: https://drks.de/search/de/trial/DRKS00027345.

Usefulness of somatosensory evoked potentials for monitoring the clinical course of patients with chronic inflammatory demyelinating polyradiculoneuropathy

INTRODUCTION/AIMS

Somatosensory evoked potentials (SSEPs) are described as a supportive tool to diagnose chronic inflammatory demyelinating polyradiculoneuropathy (CIDP); however, there is a lack of studies determining the effectiveness of SSEPs in monitoring the clinical course of individuals with this condition. The aims of this study are to evaluate the utility of SSEPs in monitoring patients with CIDP and to assess their association with clinical outcomes following immunomodulatory therapy.

METHODS

This was a single-center retrospective observational study that included patients who met European Federation of Neurological Societies and Peripheral Nerve Society criteria for CIDP between 2018 and 2023. SSEPs were performed at diagnosis and during follow-up after the start of immunomodulatory treatment. Fisher's exact test was employed to assess the association between clinical improvement and SSEP improvement.

RESULTS

Eighteen patients were included in the study. Ten patients had a typical CIDP pattern and 11 were male. In 17, SSEPs were abnormal prior to the start of immunomodulatory treatment. In patients who showed clinical improvement with immunomodulatory therapy, we observed that 15/17 had partial or complete improvement in SSEPs. Patients who showed no clinical improvement with first-line treatment exhibited worsening SSEPs. There was a significant association between clinical and SSEPs improvement (p = 0.009).

DISCUSSION

We observed a positive association between improvement in SSEPs and clinical improvement in patients with CIDP. Our data suggest that SSEPs may be useful for monitoring the clinical course of patients with CIDP, but additional, larger studies are needed.

Subcutaneous immunoglobulins (SCIG) for chronic inflammatory demyelinating polyneuropathy (CIDP): A comprehensive systematic review of clinical studies and meta-analysis

BACKGROUND

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) presents significant treatment challenges due to its chronic nature, varied clinical presentations, and rarity. Subcutaneous immunoglobulin (SCIG) has emerged as a maintenance therapy, offering potential advantages in administration and patient experience over the previously recognized intravenous immunoglobulin (IVIG).

METHODS

We included all clinical studies involving CIDP patients treated with SCIG from eleven databases up to March 2024.

RESULTS

50 clinical studies were included in the systematic review, with 22 involved in the meta-analysis. These studies offer clinical data on around 1400 CIDP patients. Almost all studies considered SCIG a maintenance therapy, with the majority of results suggesting it as a viable substitute that may offer comparable or enhanced advantages. Studies covered aspects such as efficacy, safety, quality of life, practicality, economic evaluation, and patient preference. Meta-analysis showed SCIG significantly improved muscle strength and sensory function, had fewer and milder side effects, reduced relapse rates, and received a strong preference.

CONCLUSIONS

Findings suggest that SCIG for CIDP maintenance not only provides a more feasible alternative, with economic evaluations showing considerable cost reductions over time, and patient preference for SCIG being pronounced, but may also deliver comparable or superior health outcomes. Ongoing research lines on formulations, techniques, and direct comparative studies are critical to further illuminate, enhance, and expand SCIG's role in treatment.

Immune dysregulation in chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disorder of the peripheral nerves with an incompletely understood underlying pathophysiology. This investigation focused on defining B and T cell frequencies, T cell functional capacity and innate immune system analysis in patients with CIDP.

METHODS

By using multi-parameter flow cytometry, we examined the phenotype and function of PBMCs in 25 CIDP patients who were relatively clinically stable on treatment who met EFNS/PNS criteria, 21 patients with genetically confirmed hereditary neuropathy and 25 healthy controls. We also evaluated the regulatory T cell (Treg) inhibitory capacity by co-culturing Treg and effector T cells.

RESULTS

Proinflammatory CD4 T cells, especially type 1 helper T cell (Th1) and CD8 T cells in patients with CIDP were found to have an enhanced capacity to produce inflammatory cytokines. There was no difference in frequency of Th17 regulatory cells in CIDP patients versus healthy controls, however, Treg function was impaired in CIDP patients. There was no remarkable difference in innate immune system measures. Within B cell subsets, transitional cell frequency was decreased in CIDP patients.

INTERPRETATION

Patients with CIDP clinically stable on treatment continued to show evidence of a proinflammatory state with impaired Treg function. This potentially implies an inadequate suppression of ongoing inflammation not addressed by standard of care therapies as well as persistent activity of disease while on treatment. Targeting T cells, especially inhibiting Th1 and polyfunctional CD8 T cells or improving Treg cell function could be potential targets for future therapeutic research.

Quantitative magnetic resonance neurography in chronic inflammatory demyelinating polyradiculoneuropathy: A longitudinal study over 6 years

OBJECTIVE

To evaluate magnetic resonance neurography (MRN) for the longitudinal assessment of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Prospective examination of twelve CIDP patients by neurological assessment, MRN, and nerve conduction studies in 2016 and 6 years later in 2022. Imaging parameters were compared with matched healthy controls and correlated with clinical and electrophysiological markers. The MRN protocol included T2-weighted imaging, diffusion tensor imaging (DTI), T2 relaxometry, and magnetization transfer imaging (MTI).

RESULTS

Nerve cross-sectional area (CSA) was increased in CIDP patients compared to controls (plexus: p = 0.003; sciatic nerve: p < 0.001). Over 6 years, nerve CSA decreased in CIDP patients, most pronounced at the lumbosacral plexus (p = 0.015). Longitudinally, changes in CSA correlated with changes in the inflammatory neuropathy cause and treatment validated overall disability sum score (INCAT/ODSS) (p = 0.006). High initial nerve CSA was inversely correlated with changes in the INCAT/ODSS over 6 years (p < 0.05). The DTI parameter fractional anisotropy (FA) showed robust correlations with electrodiagnostic testing both cross-sectionally and longitudinally (p < 0.05). MTI as a newly added imaging technique revealed a significantly reduced magnetization transfer ratio (MTR) in CIDP patients (p < 0.01), suggesting underlying changes in macromolecular tissue composition, and correlated significantly with electrophysiological parameters of demyelination (p < 0.05).

INTERPRETATION

This study provides evidence that changes in nerve CSA and FA reflect the clinical and electrophysiological course of CIDP patients. Initial nerve hypertrophy might predict a rather benign course or better therapy response.

Disease activity in chronic inflammatory demyelinating polyneuropathy: association between circulating B-cell subsets, cytokine levels, and clinical outcomes

Chronic inflammatory demyelinating polyneuropathy (CIDP), a common and treatable autoimmune neuropathy, is frequently misdiagnosed. The aim of this study is to evaluate the relationship between immunological markers and clinical outcome measures in a mixed cohort of patients with typical CIDP and CIDP variants at different disease stages. Twenty-three typical, 16 multifocal and five distal CIDP patients were included. Twenty-five sex and age-matched healthy controls and 12 patients with Charcot-Marie-Tooth type 1A (CMT1A) disease served as controls. Peripheral B-cell populations were analyzed by flow cytometry. IL6, IL10, TNFA mRNA and mir-21, mir-146a, and mir-155-5p expression levels were evaluated by real-time polymerase chain reaction in peripheral blood mononuclear cells (PBMC) and/or skin biopsy specimens. Results were then assessed for a possible association with clinical disability scores and intraepidermal nerve fiber densities (IENFD) in the distal leg. We detected a significant reduction in naive B cells (P ≤ 0.001), plasma cells (P ≤ 0.001) and regulatory B cells (P < 0.05), and an elevation in switched memory B cells (P ≤ 0.001) in CIDP compared to healthy controls. CMT1A and CIDP patients had comparable B-cell subset distribution. CIDP cases had significantly higher TNFA and IL10 gene expression levels in PBMC compared to healthy controls (P < 0.05 and P ≤ 0.01, respectively). IENFDs in the distal leg showed a moderate negative correlation with switched memory B-cell ratios (r = -0.51, P < 0.05) and a moderate positive correlation with plasma cell ratios (r = 0.46, P < 0.05). INCAT sum scores showed a moderate positive correlation with IL6 gene expression levels in PBMC (r = 0.54, P < 0.05). Altered B-cell homeostasis and IL10 and TNFA gene expression levels imply chronic antigen exposure and overactivity in the humoral immune system, and seem to be a common pathological pathway in both typical CIDP and CIDP variants.

Symptom and Treatment Satisfaction in Members of the US and Canadian GBS/CIDP Foundations with a Diagnosis of Chronic Inflammatory Demyelinating Polyneuropathy

INTRODUCTION

Current guidelines for defining good outcomes in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) are predominately defined by experts. At present, we do not have a patient-anchored definition of what constitutes a "good" outcome. Our study aimed to assess the symptom burden of people living with CIDP, as well as satisfaction with treatments and clinical outcomes.

METHODS

We conducted an online-survey in CIDP patients registered with the US and Canadian GBS/CIDP foundations. Respondents answered general demographic and clinical questions, as well as satisfaction with current symptom burden and treatments, plus validated outcome measures.

RESULTS

A total of 318 individuals with self-reported CIDP completed the online survey, of whom 128 (40%) considered their current disease burden as satisfactory while 190 (60%) did not. Of 305 patients who answered the treatment satisfaction question, 222(74%) were satisfied with their treatments. Patients who were satisfied with their current symptoms had, on average, better scores in quality of life and disease severity scales, although regression modeling showed that only ability to walk, stable symptoms, and health utility scores were associated with symptom satisfaction. Treatment satisfaction was associated with stable symptoms, use of IVIG, and use of one versus no medication.

CONCLUSIONS

A high proportion of members of the US and Canadian GBS/CIDP Foundations reporting a diagnosis of CIDP were unsatisfied with current symptoms, despite a high level of overall satisfaction with treatments. There is an unmet need for improving long-term outcomes in people with a diagnosis of CIDP, and for studying patient-centered long-term treatment goals.

Peptides From the Variable Domain of Immunoglobulin G as Biomarkers in Chronic Inflammatory Demyelinating Polyradiculoneuropathy

BACKGROUND AND OBJECTIVES

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a clinically heterogeneous immune-mediated disease. Diagnostic biomarkers for CIDP are currently lacking. Peptides derived from the variable domain of circulating immunoglobulin G (IgG) have earlier been shown to be shared among patients with the same immunologic disease. Because humoral immune factors are hypothesized to be involved in the pathogenesis of CIDP, we evaluated IgG variable domain-derived peptides as diagnostic biomarkers in CIDP (primary objective) and whether IgG-derived peptides could cluster objective clinical entities in CIDP (secondary objective).

METHODS

IgG-derived peptides were determined in prospectively collected sera of patients with CIDP and neurologic controls by means of mass spectrometry. Peptides of interest were selected through statistical analysis in a discovery cohort followed by sequence determination and confirmation. Diagnostic performance was evaluated for individual selected peptides and for a multipeptide model incorporating selected peptides, followed by performance reassessment in a validation cohort. Clustering of patients with CIDP based on IgG-derived peptides was evaluated through unsupervised sparse principal component analysis followed by k-means clustering.

RESULTS

Sixteen peptides originating from the IgG variable domain were selected as candidate biomarkers in a discovery cohort of 44 patients with CIDP and 29 neurologic controls. For all 16 peptides, univariate logistic regressions and ROC curve analysis demonstrated increasing peptide abundances to associate with increased odds for CIDP (area under the curves [AUCs] ranging from 64.6% to 79.6%). When including age and sex in the logistic regression models, this remained the case for 13/16 peptides. A model composed of 5/16 selected peptides showed strong discriminating performance between patients with CIDP and controls (AUC 91.5%; 95% CI 84.6%-98.4%; p < 0.001). In the validation cohort containing 45 patients and 43 controls, 2/16 peptides demonstrated increasing abundances to associate with increased odds for CIDP, while the five-peptide model demonstrated an AUC of 61.2% (95% CI 49.3%-73.2%; p = 0.064). Peptide-based patient clusters did not associate with clinical features.

DISCUSSION

IgG variable domain-derived peptides showed a valid source for diagnostic biomarkers in CIDP, albeit with challenges toward replication. Our proof-of-concept findings warrant further study of IgG-derived peptides as biomarkers in more homogeneous cohorts of patients with CIDP and controls.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that the pattern of serum IgG-derived peptide clusters may help differentiate between patients with CIDP and those with other peripheral neuropathies.

Current clinical management of CIDP with immunoglobulins in France: An expert opinion

Treatment strategies in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) must be adapted on a case-to-case basis. Validated and reproducible tools for monitoring treatment response are required at diagnosis, when initiating treatment and throughout follow-up. A task force of French neurologists, experts in neuromuscular disease reference centers, was assembled to provide expert advice on the management of typical CIDP with intravenous immunoglobulins (Ig), and to harmonize treatment practices in public and private hospitals. The task force also referred to the practical experience of treating CIDP with Ig at the diagnostic, induction and follow-up stages, including the assessment and management of Ig dependence, and following the recommendations of the French health agency.

Chronic Immune-Mediated Demyelinating Neuropathies

OBJECTIVE

This article is an overview of chronic demyelinating neuropathies and highlights the phenotypic categorization, diagnosis, and treatment of chronic immune-mediated neuropathies. The clinical and diagnostic characteristics of other chronic demyelinating neuropathies that are common mimics of immune-mediated neuropathies are also discussed.

LATEST DEVELOPMENTS

The underlying pathophysiology of chronic demyelinating neuropathies is heterogeneous, and components of both humoral and cellular immune responses are thought to play a role in the immune-mediated types of chronic demyelinating neuropathy. The role of the humoral response is highlighted with a specific focus on the relatively recent discovery of antibody-mediated antinodal and paranodal demyelinating neuropathies. Additionally, new diagnostic criteria for some of the chronic demyelinating neuropathies, as well as ways to differentiate chronic inflammatory demyelinating polyradiculoneuropathy from other chronic demyelinating polyneuropathies, are discussed.

ESSENTIAL POINTS

Chronic demyelinating neuropathies can present with overlapping clinical characteristics with seemingly subtle variations. It is clinically important to differentiate these types of neuropathies because the treatment and management can vary and affect prognosis.

Chronic inflammatory demyelinating polyradiculoneuropathy: Diagnostic problems in clinical practice in Serbia

Making diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is challenging since it can mimic a multitude of disorders, and is misdiagnosed in at least 50% of cases. We sought to determine the frequency of CIDP misdiagnosis in clinical practice in Serbia, to uncover CIDP mimics, and to identify factors that may aid in CIDP diagnosis. Our longitudinal retrospective cohort study included 86 eligible adult patients referred to the Neurology Clinic, University Clinical Centre of Serbia, with a diagnosis of CIDP. We also included 15 patients referred to us with different diagnoses that ended up having CIDP as their final diagnosis. Exactly half of patients referred as CIDP failed to meet the established diagnostic criteria (non-CIDP) and were given an alternative diagnosis at the first hospitalization. At the 1-year follow-up, the diagnosis was further revised in four subjects. Confirmed CIDP patients usually had their initial diagnosis based on the nerve conduction studies (NCS), a typical presentation with symmetrical involvement of all four limbs, as well as higher frequencies of elevated protein levels and albuminocytologic dissociation in the cerebrospinal fluid (CSF). CIDP patients also responded better to immune therapy. We found that 52% of the patients initially referred to our Clinic as CIDP were given other diagnoses after a 1-year follow-up. Out of all CIDP cases, 27% had been unrecognized prior to referral to our Center. Utilization of clear and objective indicators - conclusive NCS, improvement on therapy, and elevated CSF proteins may provide greater certainty in diagnosing CIDP.

CIDP prognosis in patients with IVIG treatment-related fluctuations

INTRODUCTION/AIMS

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired immune-mediated peripheral nerve disorder with variable prognosis and long-term dependence on immunotherapy. Frequent assessment of grip strength can be a useful tool to identify intravenous immunoglobulin (IVIG) treatment-related fluctuations (TRFs) and optimize IVIG treatment in real-time, but the long-term implications of TRFs are unknown. We aimed to explore the impact that real-time TRFs had on long-term CIDP prognosis, strength impairment, and disability.

METHODS

This retrospective observational cohort study analyzed standard of care clinical and treatment outcomes in patients who participated in a published prospective study of intra-IVIG-cycle grip strength quantification. Patients were analyzed based upon the presence or absence of TRFs, as determined in the initial prospective study.

RESULTS

Data were available for 23 CIDP patients with a mean follow-up period of 44.7 mo. There were no differences in baseline or follow-up strength, disability, or IVIG usage in patients with a low number of fluctuations compared to those with a high number of fluctuations. In both groups, drug-free remission was achieved in about one-third of patients.

DISCUSSION

TRFs are important to identify in order to optimize treatment in real time, but poorly predict long-term disease activity status. The presence of minor TRFs are unlikely to result in substantial accumulation of disability over time. Periodic IVIG optimization trials using objective outcomes are encouraged in all CIDP patients receiving chronic IVIG treatment as a means to identify the lowest effective IVIG dose and frequency.

Treatment of Chronic Inflammatory Demyelinating Polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a chronic peripheral polyneuropathy that results in disability through immune mediated nerve injury, but which not uncommonly has residual and irreversible neurologic deficits after the active inflammatory component of the disorder has been treated. Management of the condition entails addressing both the abnormal immune activity that drives ongoing or active deficits while also managing residual symptoms through supportive interventions. Immune based treatments are grounded in several important principles. First, early treatment is guided by evidence-based proven effective therapies that sequentially escalate depending on the response. Second, optimization or personalization of first line treatments is needed in order to understand the ideal dose for any given patient, and whether long term treatment is needed at all. Third, although many immunosuppressive agents may be utilized in non-responding patients or when intravenous immunoglobulin (IVIG)/corticosteroid sparing intervention is desired, all are unproven and require a delicate balance between risk, cost, and unknown likelihood of benefit that is tailored to each individual patient's unique circumstances. There is no reliable disease activity biomarker that can be used to guide treatment - a reality that makes it very challenging to optimize treatment to individual patient needs. Serial clinical assessments are key to understanding the value of continued immunotherapy or if long-term therapy is needed at all. Regardless of the immunotherapy status of a patient, equally important is addressing residual deficits through supportive interventions including physical therapy, adaptive equipment, pain management, and emotional support. This article is protected by copyright. All rights reserved.

Assessing deterioration using impairment and functional outcome measures in chronic inflammatory demyelinating polyneuropathy: a post-hoc analysis of the IOC trial

BACKGROUND AND AIMS

It is unclear whether frequently used cut-off values for outcome measures defining minimal clinically important differences (MCIDs) can accurately identify meaningful deterioration in chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

We used data from the IOC trial, in which sixty clinically stable CIDP patients were randomized to IVIg withdrawal or continuation. We calculated change scores of the Inflammatory Rasch-Built Overall Disability Scale (I-RODS), grip strength, and MRC sum score (MRC-SS) and classified visits based on a treatment anchor (i.e. decision to restart/increase treatment after reaching a predefined early endpoint of deterioration). The variability of scores in patients without deterioration was calculated using the limits of agreement. We defined optimized MCIDs for deterioration and specific combinations of MCIDs from different outcome measures, and subsequently calculated the accuracies of the (combined) MCIDs.

RESULTS

Substantial variability was found in scores of the I-RODS, grip strength and MRC-SS in patients without deterioration over time, and most MCIDs were within the limits of the variability observed in patients without deterioration. Some MCID cut-offs were insensitive but highly specific for detecting deterioration, e.g. the MCID-SE of -1.96 of the I-RODS and -2 point on the MRC-SS. Others were sensitive, but less specific, e.g. -4 centiles of the I-RODS. Some combined MCIDs resulted in high specificities and moderate sensitivities.

INTERPRETATION

Our results suggest that clinically important deterioration cannot be distinguished from variability over time with currently used MCIDs on the individual level. Combinations of MCIDs might improve the accuracy of determining deterioration, but this needs validation.

Outcome measures and biomarkers in chronic inflammatory demyelinating polyradiculoneuropathy: from research to clinical practice

Introduction: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated syndrome characterized clinically by weakness and/or numbness that evolves over 2 months or more. The heterogeneity of clinical features necessitates an individualized approach to disease monitoring that takes lessons learned from clinical trials and applies them to clinical practice.Areas covered: This review discusses the importance of clinimetrics and biomarkers in CIDP diagnosis and disease monitoring. Highlighted are the challenges of defining responses to immunotherapy, the usefulness, and limitations of utilizing evidence-based clinical outcome measures during routine clinical care, and the evolving understanding of how diagnostic and disease activity biomarkers may reshape our treatment and disease monitoring paradigms.Expert opinion: Although disability and impairment outcome measures are commonly used in CIDP to indicate disease status, the nonspecific nature of these metrics limits the ability to attribute a change in any given metric to a change in CIDP. This interpretive challenge may be magnified by inconsistencies in the direction of change as well as a strong placebo effect. There is a need to improve our understanding of minimally important changes in existing outcome measures as a means to personalize treatment and to better assess disease activity status with biomarker discovery.

Clinical outcome of CIDP one year after start of treatment: a prospective cohort study

OBJECTIVE

To assess clinical outcome in treatment-naive patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

We included adult treatment-naive patients participating in the prospective International CIDP Outcome Study (ICOS) that fulfilled the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) diagnostic criteria for CIDP. Patients were grouped based on initial treatment with (1) intravenous immunoglobulin (IVIg), (2) corticosteroid monotherapy or (3) IVIg and corticosteroids (combination treatment). Outcome measures included the inflammatory Rasch-built overall disability scale (I-RODS), grip strength, and Medical Research Council (MRC) sum score. Treatment response, treatment status, remissions (improved and untreated), treatment changes, and residual symptoms or deficits were assessed at 1 year.

RESULTS

Forty patients were included of whom 18 (45%) initially received IVIg, 6 (15%) corticosteroids, and 16 (40%) combination treatment. Improvement on ≥ 1 of the outcome measures was seen in 31 (78%) patients. At 1 year, 19 (48%) patients were still treated and fourteen (36%) patients were in remission. Improvement was seen most frequently in patients started on IVIg (94%) and remission in those started on combination treatment (44%). Differences between groups did not reach statistical significance. Residual symptoms or deficits ranged from 25% for neuropathic pain to 96% for any sensory deficit.

CONCLUSIONS

Improvement was seen in most patients. One year after the start of treatment, more than half of the patients were untreated and around one-third in remission. Residual symptoms and deficits were common regardless of treatment.

Electrophysiological predictors of response to subcutaneous immunoglobulin therapy in chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

To assess axonal function prior to subcutaneous immunoglobulin (SCIG) therapy or placebo in relation to relapse in chronic inflammatory demyelinating polyneuropathy (CIDP) to determine whether axonal damage can predict therapy response.

METHODS

Relapse rates in patients from the Polyneuropathy and Treatment with Hizentra (PATH) study, where patients were treated with placebo or SCIG (IgPro20), were analyzed by baseline (post-intravenous immunoglobulin stabilization) axonal damage (≤1 mV peroneal compound muscle action potential) status.

RESULTS

In patients with non-axonal damage, relapses were significantly higher with placebo (73.0%) than IgPro20 (0.2 g/kg: 39.1%, 0.4 g/kg: 19.2%). In patients with axonal damage, IgPro20 had no effect on relapse (placebo: 25.0%, IgPro20: 0.2 g/kg: 30.0%, 0.4 g/kg: 19.4%). Patients with axonal damage relapsed significantly less on placebo versus non-axonal damage, but they also demonstrated higher baseline disability.

CONCLUSION

Axonal damage may correspond to relapse upon treatment withdrawal; patients with axonal damage relapse less, possibly reflecting poor response to immunoglobulin therapy, while non-axonal damage patients may experience more relapse, perhaps indicating better treatment response.

SIGNIFICANCE

In CIDP patients with axonal loss, immunoglobulin therapy may not be as effective. Assessing axonal damage could help guide therapy, with immunoglobulins ideally used before substantial axonal damage arises.

What is in the Literature

This edition of What is in the Literature focuses on chronic immune neuropathies as they represent treatable conditions. There are formal criteria to solidify the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but patients are encountered who have clinical and electrodiagnostic features of CIDP but do not fulfill diagnostic criteria. These patients are addressed in recent publications. CIDP (and variants) and other forms of immune-mediated neuropathies (multifocal motor neuropathy) are responsive early on to treatment, but long-term factors are less well described, and a number of publications focus on extended consequences. Acute immune neuropathies have been described in the setting of viral illness, and recent publications look at the question as to whether they are associated with the COVID-19 pandemic. Finally, idiopathic sensory neuropathies are the most common polyneuropathy, and consensus efforts to codify features into subtypes can be used clinically for a more precise diagnosis.

Switch from intravenous to subcutaneous immunoglobulin IgPro20 in CIDP patients: a prospective observational study under real-world conditions

Background:

IgPro20 is the first approved subcutaneous immunoglobulin (SCIg) preparation for the treatment of patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Two different doses of the SCIg preparation were investigated in the pivotal PATH study. Real-world data, and particularly the efficacy of an equivalent dose switch from intravenous immunoglobulin (IVIg) to SCIg, are still not available.

Methods:

In this prospective observational study, 41 patients with CIDP treated with intravenous immunoglobulin (IVIg) were changed to an equivalent (1:1) dose of IgPro20 1 week after last IVIg treatment. Patients were examined at the time of switch from IVIg to SCIg, after 3 and after 6 months and efficacy, treatment preferences and systemic and local reactions were assessed.

Results:

Various clinical outcome parameters demonstrated overall stability regarding disability, general activity and social participation, grip and muscle strength, as well as gait impairment. Treatment satisfaction remained unchanged between IVIg and SCIg therapy. However, 88% of patients favoured treatment with subcutaneous IgPro20 over IVIg 6 months after switch to IgPro20.

Conclusion:

Results demonstrate that the switch of IVIg to an equivalent dose of SCIg represents an effective and preferred treatment option for CIDP patients.

Prognostic value of neurofilament light chain in chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyneuropathy is a neuroinflammatory disorder with considerable variation in clinical phenotype, disease progression and therapy response among patients. Recently, paranodal antibodies associated with poor response to intravenous immunoglobulin therapy and more aggressive disease course have been described in small subsets of patients, but reliable serum-based prognostic biomarkers are not yet available for the general population. In current retrospective longitudinal study, we utilized logistic regression models to investigate the associations of serum neurofilament light chain levels with 1-year disease progression and therapy response during follow-up in chronic inflammatory demyelinating polyneuropathy. One-year disease progression was defined as a decrease of four or more points (the minimal clinically important difference) on an 80-point Medical Research Council sum-score scale 1 year after sampling. Patients who, compared to treatment received at time of sampling, required therapy switch during follow-up due to insufficient effect were classified as non-responders. Serum neurofilament light chain was measured by electrochemiluminescence assay in clinical residual serum samples of 76 patients diagnosed with probable (13 patients) or definite (63 patients) chronic inflammatory demyelinating polyneuropathy according to European Federation of Neurological Societies/Peripheral Nerve Society diagnostic criteria. Eleven (15%) patients were female, and the mean (standard deviation) cohort age was 61.5 (11.7) years. In both univariate and multivariable (including demographics) models, elevated serum neurofilament light chain harboured increased odds for 1-year disease progression (respectively odds ratio, 1.049; 95% confidence interval, 1.022-1.084 and odds ratio, 1.097; 95% confidence interval, 1.045-1.169; both P = 0.001). Patients with levels above the median cohort neurofilament light chain level (28.3 pg/ml) had largely increased odds of 1-year disease progression (univariate: odds ratio, 5.597; 95% confidence interval, 1.590-26.457; P = 0.01; multivariable: odds ratio, 6.572; 95% confidence interval, 1.495-39.702; P = 0.02) and of insufficient treatment response (univariate: odds ratio, 4.800; 95% confidence interval, 1.622-16.442; P = 0.007; multivariable: odds ratio, 6.441; 95% confidence interval, 1.749-29.357; P = 0.009). In a combined approach analysis, patients with levels above median cohort serum neurofilament light chain level reported strongly increased odds of demonstrating 1-year disease progression and/or therapy non-response during follow-up (univariate: odds ratio, 6.337; 95% confidence interval, 2.276-19.469; P < 0.001; multivariable: odds ratio, 10.138; 95% confidence interval, 2.801-46.404; P = 0.001). These results show that in various logistic regression models, serum neurofilament light chain was associated with both 1-year disease progression and therapy response during follow-up in chronic inflammatory demyelinating polyneuropathy. Hence, our findings warrant further prospective research regarding the value of neurofilament light chain as potential prognostic biomarker in chronic inflammatory demyelinating polyneuropathy.

Association of serum neurofilament light chain levels with clinicopathology of chronic inflammatory demyelinating polyneuropathy, including NF155 reactive patients

OBJECTIVES

To clarify whether serum neurofilament light chains (NfLs) serve as a biomarker of axonal damage in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), especially in patients with anti-neurofascin 155 (NF155) antibodies.

METHODS

The Simoa system was used to examine serum NfL levels from 58 patients with CIDP, including 13 anti-NF155 antibody-positive patients, and from 14 age- and sex-matched healthy individuals. Serum NfL levels were evaluated before and after treatment in eight patients with anti-NF155 antibodies. Clinical features, electrophysiological findings, and cerebrospinal fluid (CSF) protein levels, were evaluated. The pathological features of sural nerves from 40 patients were also examined.

RESULTS

Serum NfL levels were significantly higher in patients with CIDP than in healthy individuals (median 29.63 vs. 7.71 pg/mL, p < 0.001) and were correlated with both modified Rankin Scale scores (r = 0.584, p < 0.001) and CSF protein levels (r = 0.432, p = 0.001). The NfL levels of anti-NF155 antibody-positive patients were higher than those of antibody-negative patients (p = 0.005). Serum NfL levels were negatively correlated with compound muscle action potential amplitudes of the tibial nerves (r =  - 0.404, p = 0.004) and positively correlated with the degree of active axonal degeneration in the pathological findings (r = 0.485, p = 0.001). In the antibody-positive group, NfL levels and antibody titers decreased after treatment in all examined patients.

CONCLUSION

Serum NfL correlated with pathological indices of axonal degeneration, and may serve as a biomarker that reflects active axonal damage of CIDP.

Changes of clinical, neurophysiological and nerve ultrasound characteristics in CIDP over time: a 3-year follow-up

OBJECTIVES

To evaluate, in a prospective study, high-resolution ultrasound (HRUS) changes of nerve segments in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and their relationships with clinical and electrodiagnostic (EDX) characteristics.

METHODS

Twenty-three consecutive patients with CIDP were included in a 3-year follow-up (FU) study. Each patient underwent neurologic examination, EDX and HRUS study. HRUS was performed on median, ulnar and peroneal nerves, yielding a total of 319 scanned nerve segments. INCAT and MRC-sum scores, motor nerve conduction velocity (NCV), compound muscle action potential (cMAP) amplitude, and nerve cross-sectional area (NCSA) were collected at baseline and at FU end, and were used for statistical analysis. Twenty-two healthy individuals, matched to patients for age and BMI, served as controls.

RESULTS

NCSA was higher in patients than in controls (p < 0.0001) and showed significant direct correlation with disease severity, and inverse correlation with NCV and cMAP amplitude, both at baseline and at FU end. Disease duration, clinical scores and EDX were predictors of NCSA enlargement at both time points. During FU, NCSA increased in 51% of nerve segments (p = 0.006), in correlation with INCAT increase and with NCV and cMAP reduction. Considering EDX changes in subgroups that reflect the different types of nerve damage, NCSA significantly increased in those nerve segments that from normal EDX switched to prevalent myelinopathic EDX characteristics.

CONCLUSIONS

Peripheral nerve size tends to increase over time in patients with CIDP, in correlation with clinical and EDX changes, in particular in those nerve segments that undergo a predominantly demyelinating damage.

Quantifying Treatment-Related Fluctuations in CIDP: Results of the GRIPPER Study

OBJECTIVE

The objective of this study was to explore the extent of IV immunoglobulin (IVIG) treatment-related fluctuations (TRFs) by using home collection of daily grip strength in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and to use that information to develop evidence-based treatment optimization strategies.

METHODS

This prospective observational study included 25 patients with well-defined CIDP. Participants recorded grip strength daily for 6 months. Disability and gait metrics were collected weekly. Serum immunoglobulin G levels were obtained at peak, trough, and midcycle IVIG intervals. Day-to-day grip strength changes <10% were considered random. To identify patients with TRFs, 3-day averaged grip strength was calculated on each consecutive day after an IVIG infusion. TRFs were defined as ≥10% 3-day averaged grip strength difference compared to the pre-IVIG baseline.

RESULTS

Participants successfully recorded grip strength on all but 9% of recordable days. Twelve patients (48%) were classified as low/no fluctuaters and 13 (52%) as frequent fluctuaters. In the frequent fluctuating group, grip strength improved over 1 week and thereafter was relatively stable until the third week after infusion. Grip strength was significantly correlated with measures of disability.

CONCLUSIONS

Grip strength collection by patients at home is reliable, valid, and feasible. A change in grip strength by ≥10% is a useful, practical, and evidence-based approach that may be used to identify clinically meaningful TRFs. From these data, we propose a treatment optimization strategy for patients with CIDP on chronic IVIG that may be applied to routine clinic care during both face-to-face and virtual video or telephone patient encounters.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov Identifier: NCT02414490.

Comprehensive approaches for diagnosis, monitoring and treatment of chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common chronic inflammatory neuropathy. CIDP is diagnosed according to the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria, which combine clinical features with the electrophysiological evidence of demyelination. However, firstly, diagnosis is challenging, as some patients e.g. with severe early axonal damage do not fulfil the criteria. Secondly, objective and reliable tools to monitor the disease course are lacking. Thirdly, about 25% of CIDP patients do not respond to evidence-based first-line therapy. Recognition of these patients is difficult and treatment beyond first-line therapy is based on observational studies and case series only. Individualized immunomodulatory treatment does not exist due to the lack of understanding of essential aspects of the underlying pathophysiology.

Novel diagnostic imaging techniques and molecular approaches can help to solve these problems but do not find enough implementation. This review gives a comprehensive overview of novel diagnostic techniques and monitoring approaches for CIDP and how these can lead to individualized treatment and better understanding of pathophysiology.

Chronic inflammatory demyelinating polyradiculoneuropathy-Diagnostic pitfalls and treatment approach

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is characterized by progressive weakness and sensory loss, often affecting patients' ability to walk and perform activities of daily living independently. With the lack of a diagnostic biomarker, the diagnosis relies on clinical suspicion, clinical findings, and the demonstration of demyelinating changes on electrodiagnostic (EDx) testing and nerve pathology. As a result, patients can often be misdiagnosed with CIDP and unnecessarily treated with immunotherapy. Interpreting the EDx testing and cerebrospinal fluid findings in light of the clinical phenotype, recognizing atypical forms of CIDP, and screening for CIDP mimickers are the mainstays of the approach to patients suspected of having CIDP, and are detailed in this review. We also review the currently available treatment options, including intravenous immunoglobulin (IVIg), corticosteroids (CCS), and plasma exchange (PE), and discuss how to approach treatment-refractory cases. Finally, we emphasize the need to adopt objective outcome measures to monitor treatment response.

The Misdiagnosis of CIDP: A Review

There is a growing realization that many patients are incorrectly diagnosed with chronic inflammatory demyelinating polyneuropathy (CIDP), with at least half of patients that carry a diagnosis of CIDP in the USA possibly having a different explanation for their neuropathy or having no neuropathy at all. Many misdiagnosed patients go on to receive costly and potentially harmful treatments for a disease that they do not have, while at the same time missing an opportunity to treat their true ailment. The cost of misdiagnosis on patients and society is not trivial. Many factors contribute to misdiagnosis. Particular points of vulnerability include the evaluation of "atypical" CIDP, interpretation of equivocal nerve conduction studies, over-reliance on elevations in cerebrospinal fluid protein concentration in indeterminate ranges, and placing excessive diagnostic weight on subjective changes following the initiation of immunotherapy. In addition to heighted awareness of the challenges, adherence to CIDP diagnostic guidelines, utilization of objective metrics to document clinical change, and referrals to CIDP centers of excellence are strategies that may improve diagnostic accuracy.