Rituximab versus placebo for chronic inflammatory demyelinating polyradiculoneuropathy: a randomized trial

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) often requires prolonged ongoing treatment to prevent worsening. The efficacy of rituximab in preventing worsening after the discontinuation of immunoglobulin therapy in patients with CIDP was assessed. In this randomized, double-blind, placebo-controlled study, conducted at seven Italian hospitals, CIDP patients under immunoglobulin therapy were assigned to receive either rituximab (1 g on Days 1, 15 and 180 ± 7) or placebo. Both groups continued their regular immunoglobulin doses for 6 months post-intervention. The primary end point was the proportion of patients who worsened in any of the following three measures at Month 12, within 6 months after immunoglobulin discontinuation: a decrease of at least one point on the adjusted INCAT score, two points on the MRC sum score, or four points on the RODS centile score. Secondary end points included the proportion of patients deteriorating at Month 18 (within 12 months after immunoglobulin discontinuation), treatment cessation due to adverse events or voluntary reasons, and the time until deterioration after immunoglobulin discontinuation. This study was registered with ClinicalTrials.gov (NCT06325943) and EUDRACT (number 2017-005034-36), and is now complete. From April 2019 to March 2022, 39 patients were recruited; two withdrew consent. The remaining 37 patients were assigned to rituximab (n = 19) or placebo (n = 18). Median age was 53 (interquartile range 45-64), with 11 (30%) females. A similar proportion of patients in both the rituximab (12/19, 63.2%) and placebo (12/18, 66.6%) groups worsened at Month 12 [odds ratio (OR) 0.86; 95% confidence interval (CI) 0.22-3.32]. No significant differences were noted at Month 18 (OR 0.62; 95% CI 0.14-2.70), or in the mean scores of each scale at Months 6, 12 and 18. The median time to worsening was 5 months for rituximab and 2 months for placebo (Log-rank P = 0.4372). Treatment was suspended due to adverse events in one rituximab patient. In this study, rituximab was not more effective than placebo in preventing clinical deterioration following the discontinuation of immunoglobulin therapy in CIDP. Further studies might evaluate the efficacy of more frequent or earlier administration of rituximab.

Nerve ultrasound helps to distinguish CIDP patients with diabetes from patients with diabetic polyneuropathy

Diabetic polyneuropathy (DPN) shares overlapping clinical and electrodiagnostic features with chronic inflammatory demyelinating polyneuropathy (CIDP), which complicates the differential diagnosis of CIDP in diabetic patients. 32 patients with diabetes mellitus and CIDP, 68 patients with CIDP without diabetes, 83 patients with DPN, and 28 diabetic patients without polyneuropathy were examined using clinical scores (Overall Neuropathy Limitation Scale (ONLS), Neuropathy Symptom Score, Neuropathy Deficit Score), nerve conduction studies, and nerve ultrasound (Ultrasound Pattern Sum Score (UPSS)). The ONLS was significantly higher in the CIDP patients with diabetes than in DPN (median [interquartile range]: 4.0 [3.0] vs. 0 [1.0], p < 0.001) as well as the UPSS (4.0 [6.0] vs. 0 [2.9], p < 0.001). Multiple binary logistic regression revealed UPSS and ONLS as statistically significant predictors to differentiate between CIDP with diabetes and DPN. Receiver operating characteristic curve analysis showed the ONLS with an area under the curve (AUC) of 0.918 (95% CI: 0.868-0.0.967, p < 0.001). The UPSS total score had an AUC of 0.826 (95% CI: 0.743-0.909, p < 0.001). An UPSS ≥ 2.5 had a sensitivity of 77.4% and a specificity of 68.7% to detect CIDP. An ONLS ≥ 1.5 had a sensitivity of 87.1% and a specificity of 81.9% to detect CIDP. ROC curve analysis of a composite score of ONLS and UPSS revealed an AUC of 0.959 (95% CI: 0.928-0.991, p < 0.001). CIDP is an important differential diagnosis in people with diabetes mellitus. This study reports that the UPSS is well suited to differentiate between DPN and CIDP.

ITPR3-associated neuropathy: Report of a further family with adult onset intermediate Charcot-Marie-Tooth disease

BACKGROUND AND PURPOSE

ITPR3 encodes type 3 inositol-tri-phosphate receptor (IP3R3), a protein expressed in Schwann cells, predominantly in the paranodal region, and involved in the regulation of Ca2+ release from the endoplasmic reticulum. Dominant variants in ITPR3 have recently been recognized as a rare cause of intermediate Charcot-Marie-Tooth disease (CMT).

METHODS

We collected the clinical data of a family with autosomal dominant neuropathy whose proband was diagnosed with chronic inflammatory demyelinating polyneuropathy (CIDP) for many years. The genetic diagnosis was achieved by whole exome sequencing.

RESULTS

The proband developed symmetrical sensory-motor neuropathy with demyelinating features at 32 years old. He was diagnosed with CIDP and received numerous immunomodulatory treatments. However, his condition progressed, leading to severe proximal leg and hand atrophy that confined him to a wheelchair at 60 years. The patient's two sons began to exhibit symptoms suggestive of neuropathy shortly after age 30 years, and the condition was reoriented as inherited. Exome sequencing identified a heterozygous c.4271C > T variant in the ITPR3 gene segregating with the disease. Nerve conduction studies showed a combination of demyelinating and axonal features that vary by nerve, disease duration, and patient. A uniform thickening of the nerves was identified on nerve echography, as was distal symmetric fatty infiltration in lower limb muscle imaging.

CONCLUSIONS

The c.4271C > T ITPR3 variant causes a late onset CMT that can be considered an intermediate CMT. Considering the electrophysiological findings and the distribution of IP3R3, we hypothesize that this variant could start as nodal dysfunction that progresses to widespread nerve degeneration.

Animal models of immune-mediated demyelinating polyneuropathies

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

Charcot-Marie-Tooth type 2CC misdiagnosed as Chronic Inflammatory Demyelinating Polyradiculoneuropathy

BACKGROUND AND AIMS

Charcot-Marie-Tooth (CMT) is a heterogeneous group of genetic neuropathies and is typically characterized by distal muscle weakness, sensory loss, pes cavus and areflexia. Herein we describe a case of CMT2CC presenting with proximal muscle weakness and equivocal electrophysiological features, that was misdiagnosed as chronic inflammatory demyelinating polyneuropathy (CIDP).

CASE REPORT

A 30-year-old woman complained of proximal muscle weakness with difficulty climbing stairs. Neurological examination showed weakness in lower limb (LL) muscles, that was marked proximally and mild distally, and absence of deep tendon reflexes in the ankles. Nerve conduction studies (NCS) showed sensory-motor neuropathy with non-uniform NC velocity and a partial conduction block (CBs) in peroneal nerve and tibial nerves. Thus, a diagnosis of CIDP was entertained and the patient underwent ineffective treatment with intravenous immunoglobulins. At electrophysiological revaluation CB in peroneal nerve was undetectable as also distal CMAP had decreased whereas the CBs persisted in tibial nerves. Hypothesizing a hereditary neuropathy, we examined the proband's son, who presented mild weakness of distal and proximal muscles at lower limbs. Neurophysiological investigation showed findings consistent with an intermediate-axonal electrophysiological pattern. A targeted-NGS including 136 CMT genes showed the heterozygous frameshift mutation (c.3057dupG; p.K1020fs*43) in the NEFH gene, coding for the neurofilament heavy chain and causing CMT2CC.

INTERPRETATION

Diagnosis of a genetic neuropathy may be challenging when clinical features are atypical and/or electrophysiological features are misleading. The most common misdiagnosis is CIDP. Our report suggests that also CMT2CC patients with proximal muscle weakness and equivocal electrophysiological features might be misdiagnosed as CIDP.

Unraveling the association between chronic inflammatory demyelinating polyradiculoneuropathy and peritoneal Dialysis

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare disease seen in the general population and has been reported as showing an increased incidence in the peritoneal dialysis (PD) population, as documented in case reports.

METHODS

We conducted a case-control study using data from the Taichung Veterans General Hospital electric medical record database from the years 2010 to 2023. We defined cases as CIDP with End-stage kidney disease (ESKD) and controls as without CIDP. A logistic regression analysis was used to investigate the association between CIDP and dialysis modality, age, gender, dialysis duration, plasma potassium > 5.5 mEq/L and < 2.5 mEq/L, and intact parathyroid hormone (i-PTH) > 613 pg/mL.

RESULTS

Our findings suggest that PD may be a risk factor in the ESKD population (Odds ratio: 5.125, C.I.: 1.078 ~ 24.372, p = 0.040) according to logistic regression analysis. Dialysis duration, gender, diabetes mellitus, HbA1c > 7%, hypokalemia, hyperkalemia, and hyperparathyroidism did not show an association with CIDP.

CONCLUSION

There seems to be an association between PD and CIDP in this case-control study. Possible mechanisms may involve systemic inflammation induced by peritoneal dialysate exchange or the content of the dialysate. Further studies are still needed.

Nerve sonography to detect intraneural microvascularity in patients with peripheral neuropathy

OBJECTIVE

We assessed microvessel flow within peripheral nerves using nerve sonography in patients with peripheral neuropathy.

METHODS

This study included consecutive patients with peripheral neuropathy who were admitted to our hospital. The patients were divided into two groups: inflammatory neuropathies for immune-mediated neuropathies, such as Guillain - Barré syndrome and chronic inflammatory demyelinating polyneuropathy, and the rest were defined as non-inflammatory neuropathies. We assessed nerve size and intraneural blood flow at four sites on each median and ulnar nerve. Blood flow was evaluated using color Doppler imaging, advanced dynamic flow (ADF), and superb microvascular imaging (SMI) techniques.

RESULTS

Thirty-nine patients (median age, 60.0 years; 20 male) were enrolled in this study. An increase in intraneural blood flow was observed in five patients when evaluated by color Doppler, five patients by ADF, and 13 patients by SMI. An overall analysis of the three methods showed that intraneural blood flow was significantly higher in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy (54.2% vs. 0%, p = 0.0005).

CONCLUSIONS

Intraneural hypervascularization is more frequent in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy.

SIGNIFICANCE

Evaluation of microvessel flow within peripheral nerves may contribute to the diagnosis of peripheral neuropathy.

Robot-assisted gait training in patients with various neurological diseases: A mixed methods feasibility study

BACKGROUND

Walking impairment represents a relevant symptom in patients with neurological diseases often compromising social participation. Currently, mixed methods studies on robot-assisted gait training (RAGT) in patients with rare neurological diseases are lacking. This study aimed to explore the feasibility, acceptability, goal attainment and preliminary effects of RAGT in patients with common and rare neurological diseases and understand the intervention context and process.

METHODS

A mixed-methods feasibility study was conducted at an Austrian rehabilitation centre. Twenty-eight inpatients after stroke in the subacute and chronic phases, with multiple sclerosis, Parkinson's disease, spinal cord injury, spinocerebellar ataxia, acute/chronic inflammatory demyelinating polyneuropathy and motor neuron disease were included. Patients received RAGT for 45 minutes, 4x/week, for 4 weeks. Baseline and post-intervention assessments included gait parameters, walking and balance, and questionnaires. Semi-structured observations were conducted twice during the intervention period and analysed using thematic analysis. Descriptive statistics within the respective disease groups and calculation of effect sizes for the total sample were performed. Triangulation was employed to develop a deeper understanding of the research topic.

RESULTS

Data from 26 patients (mean age 61.6 years [standard deviation 13.2]) were analysed. RAGT was highly accepted by patients and feasible, indicated by recruitment, retention, and adherence rates of 84.8% (95% confidence interval, CI 0.7-0.9), 92.2% (95% CI 0.7-1.0) and 94.0% (95% CI 91.4-96.2), respectively. Goal attainment was high, and only mild adverse events occurred. Improvements in walking speed (10-Metre Walk Test, effect size r = 0.876), walking distance (6-Minute Walk Test, r = 0.877), functional mobility (Timed Up and Go, r = 0.875), gait distance (r = 0.829) and number of steps (r = 0.834) were observed. Four themes were identified: familiarising with RAGT; enjoyment and acceptance through a trusting therapeutic relationship; actively interacting; and minimising dissatisfaction.

DISCUSSION

Sufficiently powered randomised controlled trials are needed to validate our results.

TRIAL REGISTRATION

German Clinical Trials Register, DRKS00027887.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION NUMBER

NCT05877040.

Efficacy and Safety of Rescue Treatment with Plasma Exchange in Patients with Acute Inflammatory Neurological Disorders: A Single Center Experience

BACKGROUND

Therapeutic plasma exchange (TPE) is a highly effective rescue treatment for patients with acute exacerbation of neuroimmunological disease that removes circulating autoantibodies and inflammatory components from the bloodstream. The aims of this study are to explore the safety and the effectiveness of TPE in patients with autoimmune neurological disorders.

METHODS

We retrospectively evaluated the frequency of adverse events (AEs) and the effectiveness of TPE using the modified Ranking Scale (mRS) in patients with acute neurological flares who underwent TPE at the University Hospital of Palermo.

RESULTS

Of 59 patients, the majority underwent TPE due to multiple sclerosis (MS) relapse. In 23.7% of cases, TPE was performed before obtaining a definite diagnosis due to the severity of the clinical presentation. After TPE, the mRS score was globally reduced (p < 0.0001), and this effect was marked in patients with MS, Guillain-Barré syndrome, and myasthenia gravis crisis but not in those with paraneoplastic syndromes. Circulating pathogenetic antibodies, younger age, and the early use of TPE were factors strongly associated with TPE effectiveness. The overall safety profile of TPE was satisfactory with an AE frequency of 15%.

CONCLUSIONS

These results highlight the early use of TPE in patients with circulating pathogenetic antibodies as well as its favorable safety profile.

Whole-body magnetic resonance neurography in patients with chronic inflammatory demyelinating polyneuropathy

INTRODUCTION/AIMS

Whole-body magnetic resonance neurography (MRN) is an imaging modality that shows peripheral nerve signal change in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We aimed to explore the diagnostic potential of whole-body MRN and its potential as a monitoring tool after immunotherapy in treatment-naïve CIDP patients.

METHODS

Whole-body MRN using coronal 3-dimensional short tau inversion recovery (STIR) sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE) techniques was performed in patients being investigated for CIDP and in healthy controls. Baseline clinical neuropathy scales and electrophysiologic parameters were collected, and MRN findings were compared before and after CIDP treatment.

RESULTS

We found highly concordant symmetrical thickening and increased T2 signal intensities in the brachial/lumbosacral plexus, femoral, or sciatic nerves in five of the eight patients with a final diagnosis of CIDP and none of the healthy controls. There were no treatment-related imaging changes in five patients with CIDP who completed a follow-up study. Diffuse, symmetrical thickening, and increased T2 signal in root, plexus, and peripheral nerves were found in two patients ultimately excluded due to a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome in addition to signal changes in the muscles, bony lesions, organomegaly, and lymphadenopathy.

DISCUSSION

Whole-body MRN imaging shows promise in detecting abnormalities in proximal nerve segments in patients with CIDP. Future studies evaluating the role of MRN in assessing treatment response should consider follow-up scans after treatment durations of more than 4 months.

Combined Central and Peripheral Demyelination (CCPD) Associated with MOG Antibodies: Report of Four New Cases and Narrative Review of the Literature

Background/Objectives: Myelin oligodendrocyte glycoprotein (MOG) is exclusively expressed in the central nervous system (CNS) and is found on the outer surface of oligodendrocytes. Antibodies to MOG are associated with CNS demyelination, whereas peripheral nervous system (PNS) demyelination is seldom reported to be related to MOG-IgG. Methods: The database of patients seen in our neurological academic center was searched for MOG-IgG seropositivity and concomitant demyelinating polyneuropathy. For the purpose of the review, in March 2024, we searched for case reports and case series in the following databases: PubMed, Scopus, Cochrane, and ScienceDirect. Inclusion criteria were MOG-IgG seropositivity and demyelinating polyneuropathy. Exclusion criteria were type of publication other than case reports and case series, unconfirmed diagnosis of demyelinating polyneuropathy, and other diseases causing demyelination in either the CNS or PNS. Critical appraisal of the selected case reports and case series was realized by JBI. Results: Four new cases were identified with MOG-IgG and confirmed demyelinating polyneuropathy. This review identified 22 cases that have been published since 2018. Clinical, imaging, neurophysiological, and immunological characteristics, as well as treatment options and outcomes are presented and compared to those of other cases with combined central and peripheral demyelination (CCPD). Conclusions: The pathogenetic mechanism is unclear; thus, different hypotheses are discussed. New case reporting and large cohort studies will help further the exploration of the underlying mechanism and guide more effective therapeutic interventions.

Conduction slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies: Electrophysiology meets pathology

Nerve conduction studies are usually the first diagnostic step in peripheral nerve disorders and their results are the basis for planning further investigations. However, there are some commonplaces in the interpretation of electrodiagnostic findings in peripheral neuropathies that, although useful in the everyday practice, may be misleading: (1) conduction block and abnormal temporal dispersion are distinctive features of acquired demyelinating disorders; (2) hereditary neuropathies are characterized by uniform slowing of conduction velocity; (3) axonal neuropathies are simply diagnosed by reduced amplitude of motor and sensory nerve action potentials with normal or slightly slow conduction velocity. In this review, we reappraise the occurrence of uniform and non-uniform conduction velocity slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies attempting, with a translational approach, a correlation between electrophysiological and pathological features as derived from sensory nerve biopsy in patients and animal models. Additionally, we provide some hints to navigate in this complex field.

Neuropathy in ARSACS is demyelinating but without typical nerve enlargement in nerve ultrasound

BACKGROUND

To specify peripheral nerve affection in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) by correlating high-resolution nerve ultrasound and nerve conduction studies.

METHODS

We assessed a cohort of 11 ARSACS patients with standardized nerve conduction studies and high-resolution ultrasound of peripheral nerves and compared nerve ultrasound findings to a healthy control group matched for age, sex, size and weight.

RESULTS

Mean age of patients was 39.0 (± 14.1) years and disease duration at assessment 30.6 (± 12.5) years. All patients presented with a spasticity, ataxia and peripheral neuropathy. Neuropathy appeared to be primarily demyelinating in 9/11 cases and was not classifiable in 2/11 cases due to not evocable potentials. Nerve ultrasound revealed a normal ultrasound pattern sum score (UPSS) in each ARSACS patient and no significant nerve enlargement compared to the control group.

CONCLUSIONS

Peripheral neuropathy in ARSACS showed primarily demyelinating rather than axonal characteristics and presented without nerve enlargement. As demyelinating neuropathies do commonly present enlarged nerves we recommend further genetic testing of the SACS gene in patients who present with this combination of demyelinating neuropathy without nerve enlargement. ARSACS cases that initially presented only with neuropathy without spasticity or ataxia and therefore were misdiagnosed as Charcot-Marie-Tooth disease are supporting this suggestion.

Sensory Chronic Inflammatory Demyelinating Polyradiculoneuropathy: Neglected Immunotherapy-Responsive Sensory Neuropathy

BACKGROUND AND PURPOSE

To report an improvement with immunotherapy in 34 (85%)/40 patients who required an immunotherapy among 56 patients with sensory chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Sensory CIDP was diagnosed when two inclusion criteria are met: 1) acquired, chronic progressive or relapsing symmetrical or asymmetrical sensory polyneuropathy that had progressed for >2 months; and 2) definite electrophysiological and/or biopsy evidence of demyelinating neuropathy.

RESULTS

Fifty-six patients with sensory CIDP were identified. Evidence of demyelination was obtained from by the routine motor nerve conduction study (NCS) in 39 (70%) patients, from a nerve biopsy in 10, and from a near-nerve needle sensory NCS in 7 patients. The most prominent laboratory abnormality was a high protein level in the cerebrospinal fluid in 21 (49%) of 43 tested patients. Immunotherapy was required in 41 (79%) of the 52 followed-up patients. An improvement with immunotherapy was observed in 36 (88%)/41 patients. In three patients, motor weakness developed in 5-8 years' follow-up period and so, their diagnosis was changed to CIDP.

CONCLUSIONS

Sensory CIDP is responded to an immunotherapy in 88% of the treated patients. Sensory CIDP was diagnosed by the routine motor NCS in 70% of patients and by a sural nerve biopsy in 18% of patients. Thus, sensory CIDP should be recognized as a treatable CIDP variant among the different types of "idiopathic sensory neuropathy."

Prevalence and clinical profiles of anti-myelin-associated glycoprotein neuropathy in Japan: A nationwide survey study of 133 patients

BACKGROUND AND PURPOSE

The aim of this study was to determine the prevalence of anti-myelin-associated glycoprotein (MAG) neuropathy and the current status of such patients in Japan.

METHODS

We conducted a nationwide survey in 2021 using established epidemiological methods. Questionnaires were sent to all neurology and pediatric neurology departments throughout Japan to identify patients with anti-MAG neuropathy. An initial questionnaire was used to determine the number of patients, with a second one used to collect detailed clinical information.

RESULTS

The estimated number of patients with anti-MAG neuropathy was 353, with a prevalence of 0.28 per 100,000 and an incidence of 0.05 per 100,000. The detailed clinical profiles of 133 patients were available. The median (range) age of onset was 67 (30-87) years, with a prominent peak in the age range 66-70 years, and the male-to-female ratio was 3.6. Most patients had distal sensory-predominant polyneuropathy, and neuropathic pain (50%), or sensory ataxia (42%), while 18% had Waldenström's macroglobulinemia or multiple myeloma. Intravenous immunoglobulin was the most frequently used treatment (65%), but the response rate was <50%, whereas rituximab was given in 32% of patients, and 64% of these showed improvement. At the last visit, 27% of patients could not walk independently.

CONCLUSIONS

This study on anti-MAG neuropathy provides updated insights into the epidemiology of this disease, clinical profiles, and treatment approaches in Japan. Rituximab therapy, used for only one-third of the patients, demonstrated efficacy. During the final visit, a quarter of the patients were unable to walk independently. Further studies are warranted to determine the optimal management of this rare and intractable disorder.

Impact of 2021 European Academy of Neurology/Peripheral Nerve Society diagnostic criteria on diagnosis and therapy of chronic inflammatory demyelinating polyradiculoneuropathy variants

BACKGROUND AND PURPOSE

There are different criteria for the diagnosis of different variants of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) guidelines provide specific clinical criteria for each CIDP variant even if their therapeutical impact has not been investigated.

METHODS

We applied the clinical criteria for CIDP variants of the 2021 EAN/PNS guidelines to 369 patients included in the Italian CIDP database who fulfilled the 2021 EAN/PNS electrodiagnostic criteria for CIDP.

RESULTS

According to the 2021 EAN/PNS clinical criteria, 245 patients achieved a clinical diagnosis of typical CIDP or CIDP variant (66%). We identified 106 patients with typical CIDP (29%), 62 distal CIDP (17%), 28 multifocal or focal CIDP (7%), four sensory CIDP (1%), 27 sensory-predominant CIDP (7%), 10 motor CIDP (3%), and eight motor-predominant CIDP (2%). Patients with multifocal, distal, and sensory CIDP had milder impairment and symptoms. Patients with multifocal CIDP had less frequently reduced conduction velocity and prolonged F-wave latency and had lower levels of cerebrospinal fluid protein. Patients with distal CIDP more frequently had reduced distal compound muscle action potentials. Patients with motor CIDP did not improve after steroid therapy, whereas those with motor-predominant CIDP did. None of the patients with sensory CIDP responded to steroids, whereas most of those with sensory-predominant CIDP did.

CONCLUSIONS

The 2021 EAN/PNS criteria for CIDP allow a better characterization of CIDP variants, permitting their distinction from typical CIDP and more appropriate treatment for patients.

Neuromuscular ultrasound in combination with nerve conduction studies helps identify inflammatory motor neuropathies from lower motor neuron syndromes

BACKGROUND AND PURPOSE

Identifying patients with inflammatory motor neuropathies (IMNs) is warranted since effective treatments are available and the prognosis of these patients differs from that of amyotrophic lateral sclerosis patients.

METHODS

Between January 2019 and May 2022, 102 consecutive treatment-naïve lower motor neuron syndrome (LMNS) patients were recruited; these patients were suspected of having multifocal motor neuropathy, pure motor chronic inflammatory demyelinating polyneuropathy or amyotrophic lateral sclerosis with initial lower motor neuron presentation. Neuromuscular ultrasound (US) and nerve conduction studies (NCSs) were conducted at baseline. Relevant diagnostic investigations were performed if clinically warranted. The proposed US evidence of IMN was as follows: (i) nerve enlargement at ≥1 of the predetermined sites or (ii) absence of high intensity fasciculations in predefined muscle groups. Final diagnoses were made by experienced physicians after a prolonged follow-up period (≥12 months). IMN patients were defined as LMNS patients who experienced convincing improvements in response to immunotherapies. IMN patients without electrodiagnostic demyelinating features were diagnosed with treatment-responsive LMNS (TR-LMNS).

RESULTS

In total, 16 patients were classified as IMN, including nine chronic inflammatory demyelinating polyneuropathy/multifocal motor neuropathy patients and seven TR-LMNS patients. Six TR-LMNS patients were identified by neuromuscular US. The sensitivity and specificity of NCSs, nerve US and muscle US were 56.3% and 100%, 43.8% and 90.7% and 68.8% and 97.7%, respectively. When these three modalities were combined, the sensitivity and specificity were 93.8% and 88.4%, respectively.

CONCLUSION

Neuromuscular US studies are supplementary modalities to NCSs, and the combined use of these techniques might improve the identification of IMNs in LMNS patients.

Typical CIDP, distal variant CIDP, and anti-MAG antibody neuropathy: An ultra-high frequency ultrasound comparison of nerve structure

To date, little is known about the usefulness of ultra-high frequency ultrasound (UHF-US, 50-70 MHz) in clinical practice for the diagnosis of dysimmune neuropathies. We present a prospective study aimed at comparing UHF-US alterations of nerves and fascicles in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), distal CIDP (d-CIDP) and anti-MAG neuropathy and their relationships with clinical and electrodiagnostic (EDX) features. 28 patients were included (twelve CIDP, 6 d-CIDP and 10 anti-MAG) and ten healthy controls. Each patient underwent neurological examination, EDX and UHF-US study of median and ulnar nerves bilaterally. UHF-US was reliable in differentiating immune neuropathies from controls when using mean and/or segmental nerve and/or fascicle cross-sectional area (CSA); furthermore, fascicle ratio (fascicle/nerve CSA) was a reliable factor for differentiating d-CIDP from other types of polyneuropathies. The fascicle CSA appears to be more increased in CIDP and its variant than in anti-MAG neuropathy. UHF-US offers information beyond simple nerve CSA and allows for a better characterization of the different forms of dysimmune neuropathies.

Nodal-paranodal antibodies in HIV-immune mediated radiculo-neuropathies: Clinical phenotypes and relevance

BACKGROUND

The frequency of nodal-paranodal antibodies in HIV-infected patients with chronic immune-mediated radiculo-neuropathies (IMRN) has not been previously described.

METHODS

HIV-infected patients who met the inclusion criteria for chronic IMRN were screened for immunoglobulin G (IgG) antibodies directed against nodal (neurofascin (NF)186) and paranodal (NF155, contactin-1 (CNTN1) and contactin-associated protein(Caspr1)) cell adhesion molecules, using a live, cell-based assay. To explore potential pathogenicity, binding of human IgG to myelinated co-cultures was assessed by incubation with patients' sera positive for nodal or paranodal antibodies. Normal human serum was added as a source of complement to assess for complement activation as a mechanism for myelin injury.

RESULTS

Twenty-four HIV-infected patients with IMRN were included in the study, 15 with chronic inflammatory demyelinating polyneuropathy (CIDP), 4 with ventral root radiculopathies (VRR), and 5 with dorsal root ganglionopathies (DRG). Five patients with CIDP had combined central and peripheral demyelination (CCPD). Three patients (12.7%) tested positive for neurofascin IgG1 antibodies in the following categories: 1 patient with VRR was NF186 positive, and 2 patients were NF155 positive with DRG and mixed sensory-motor demyelinating neuropathy with optic neuritis, respectively.

CONCLUSION

The frequency of nodal-paranodal antibodies is similar among IMRN regardless of HIV status. Interpretation of the results in the context of HIV is challenging as there is uncertainty regarding pathogenicity of the antibodies, especially at low titres. Larger prospective immune studies are required to delineate pathogenicity in the context of HIV, and to establish a panel of antibodies to predict for a particular clinical phenotype.

The Impact of Fatty Infiltration on MRI Segmentation of Lower Limb Muscles in Neuromuscular Diseases: A Comparative Study of Deep Learning Approaches

BACKGROUND

Deep learning methods have been shown to be useful for segmentation of lower limb muscle MRIs of healthy subjects but, have not been sufficiently evaluated on neuromuscular disease (NDM) patients.

PURPOSE

Evaluate the influence of fat infiltration on convolutional neural network (CNN) segmentation of MRIs from NMD patients.

STUDY TYPE

Retrospective study.

SUBJECTS

Data were collected from a hospital database of 67 patients with NMDs and 14 controls (age: 53 ± 17 years, sex: 48 M, 33 F). Ten individual muscles were segmented from the thigh and six from the calf (20 slices, 200 cm section).

FIELD STRENGTH/SEQUENCE

A 1.5 T. Sequences: 2D T1 -weighted fast spin echo. Fat fraction (FF): three-point Dixon 3D GRE, magnetization transfer ratio (MTR): 3D MT-prepared GRE, T2: 2D multispin-echo sequence.

ASSESSMENT

U-Net 2D, U-Net 3D, TransUNet, and HRNet were trained to segment thigh and leg muscles (101/11 and 95/11 training/validation images, 10-fold cross-validation). Automatic and manual segmentations were compared based on geometric criteria (Dice coefficient [DSC], outlier rate, absence rate) and reliability of measured MRI quantities (FF, MTR, T2, volume).

STATISTICAL TESTS

Bland-Altman plots were chosen to describe agreement between manual vs. automatic estimated FF, MTR, T2 and volume. Comparisons were made between muscle populations with an FF greater than 20% (G20+) and lower than 20% (G20-).

RESULTS

The CNNs achieved equivalent results, yet only HRNet recognized every muscle in the database, with a DSC of 0.91 ± 0.08, and measurement biases reaching -0.32% ± 0.92% for FF, 0.19 ± 0.77 for MTR, -0.55 ± 1.95 msec for T2, and - 0.38 ± 3.67 cm3 for volume. The performances of HRNet, between G20- and G20+ decreased significantly.

DATA CONCLUSION

HRNet was the most appropriate network, as it did not omit any muscle. The accuracy obtained shows that CNNs could provide fully automated methods for studying NMDs. However, the accuracy of the methods may be degraded on the most infiltrated muscles (>20%).

EVIDENCE LEVEL

4.

TECHNICAL EFFICACY

Stage 1.

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.

Epidemiology of Chronic Inflammatory Demyelinating Polyneuropathy in South Korea: A Population-Based Study

BACKGROUND AND PURPOSE

We performed a population-based study to determine the prevalence and incidence of chronic inflammatory demyelinating polyneuropathy (CIDP) in South Korea using data from the Korean Health Insurance Review and Assessment Service (HIRA) database.

METHODS

Data recorded in the HIRA database between January 2016 and December 2020 were analyzed. The inclusion criteria in this study for patients with CIDP were a diagnostic code of G61.8 in the seventh and eighth revision of the Korean Standard Classification of Disease and a >3-month history of oral immunosuppressant use. The age-adjusted incidence rate and prevalence of CIDP in South Korea were also analyzed.

RESULTS

CIDP was newly diagnosed in 953 patients during the study period. The mean age at diagnosis was 58.36 years, and the male-to-female ratio was 1.74. The age-adjusted incidence rates were 0.22, 0.21, 0.23, 0.30, and 0.25 per 100,000 person-years in 2016, 2017, 2018, 2019, and 2020, respectively. The age-adjusted prevalence was estimated at 1.16 per 100,000 persons in 2020. Age and the Elixhauser Comorbidity Index were associated with the in-hospital mortality of patients with CIDP. Infection and cardiovascular disease (CVD) were also significantly associated with the in-hospital mortality of those patients. Acute-onset CIDP was initially diagnosed in an estimated 101 out of 953 patients with CIDP.

CONCLUSIONS

The prevalence and incidence rates of CIDP in South Korea were comparable between this nationwide cohort study and previous studies. Common comorbidities such as CVD and diabetes should be appropriately monitored in patients with CIDP to prevent a poor prognosis and socioeconomic burden.

High-dose pharmaceutical-grade biotin in patients with demyelinating neuropathies: a phase 2b open label, uncontrolled, pilot study

BACKGROUND

We proposed to investigate high-dose pharmaceutical-grade biotin in a population of demyelinating neuropathies of different aetiologies, as a proof-of-concept.

METHODS

Phase IIb open label, uncontrolled, single center, pilot study in 15 patients (three groups of five patients) with chronic demyelinating peripheral neuropathy, i.e. chronic inflammatory demyelinating polyradiculoneuropathy, anti-myelin-associated glycoprotein neuropathy and Charcot-Marie-Tooth 1a or 1b. The investigational product was high-dose pharmaceutical-grade biotin (100 mg taken orally three times a day over a maximum of 52 weeks. The primary endpoint was a 10% relative improvement in 2 of the following 4 electrophysiological variables: motor nerve conduction velocity, distal motor latency, F wave latency, duration of the compound muscle action potential. The secondary endpoints included Overall Neuropathy Limitations Scale (ONLS) score, Medical Research Council (MRC) sum score, Inflammatory Neuropathy Cause and Treatment (INCAT) sensory sum score, 10-m walk test, 6-min walk test, posturography parameters, and nerve excitability variables.

RESULTS

The primary endpoint was reached in one patient. In the full population analysis, some secondary endpoints parameters improved: MRC score, INCAT sensory sum score, 6-min walk distance, strength-duration time constant, and rheobase. There was a positive correlation between the improvement in the 6-min walk distance and the strength-duration time constant. Regarding the safety results, 42 adverse events occurred, of which three were of severe intensity but none was considered as related to the investigational product.

CONCLUSIONS

Even if the primary endpoint was not met, administration of high-dose pharmaceutical-grade biotin led to an improvement in various sensory and motor parameters, gait abilities, and nerve excitability parameters. The tolerance of the treatment was satisfactory.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02967679; date 2016/12/05.

Clinical outcome in chronic inflammatory demyelinating polyneuropathy: Facing variability

See article on pages 388–396 in this issue.

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.

Hyaluronidase-facilitated subcutaneous immunoglobulin 10% as maintenance therapy for chronic inflammatory demyelinating polyradiculoneuropathy: The ADVANCE-CIDP 1 randomized controlled trial

BACKGROUND AND AIMS

ADVANCE-CIDP 1 evaluated facilitated subcutaneous immunoglobulin (fSCIG; human immunoglobulin G 10% with recombinant human hyaluronidase) efficacy and safety in preventing chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) relapse.

METHODS

ADVANCE-CIDP 1 was a phase 3, double-blind, placebo-controlled trial conducted at 54 sites in 21 countries. Eligible adults had definite or probable CIDP and adjusted Inflammatory Neuropathy Cause and Treatment (INCAT) disability scores of 0-7 (inclusive), and received stable intravenous immunoglobulin (IVIG) for ≥12 weeks before screening. After stopping IVIG, patients were randomized 1:1 to fSCIG 10% or placebo for 6 months or until relapse/discontinuation. fSCIG 10% was administered at the same dose (or matching placebo volume) and interval as pre-randomization IVIG. The primary outcome was patient proportion experiencing CIDP relapse (≥1-point increase in adjusted INCAT score from pre-subcutaneous treatment baseline) in the modified intention-to-treat population. Secondary outcomes included time to relapse and safety endpoints.

RESULTS

Overall, 132 patients (mean age 54.4 years, 56.1% male) received fSCIG 10% (n = 62) or placebo (n = 70). CIDP relapse was reduced with fSCIG 10% versus placebo (n = 6 [9.7%; 95% confidence interval 4.5%, 19.6%] vs n = 22 [31.4%; 21.8%, 43.0%], respectively; absolute difference: -21.8% [-34.5%, -7.9%], p = .0045). Relapse probability was higher with placebo versus fSCIG 10% over time (p = .002). Adverse events (AEs) were more frequent with fSCIG 10% (79.0% of patients) than placebo (57.1%), but severe (1.6% vs 8.6%) and serious AEs (3.2% vs 7.1%) were less common.

INTERPRETATION

fSCIG 10% more effectively prevented CIDP relapse than placebo, supporting its potential use as maintenance CIDP treatment.

Hereditary Neuralgic Amyotrophy with a Lesion Distal to the Brachial Plexus on Magnetic Resonance Imaging

A 35-year-old woman first experienced left upper limb weakness at 17 years old, after which it repeatedly recurred and then remitted. She was diagnosed with carpal tunnel syndrome with median nerve hyperintensity by magnetic resonance imaging (MRI). Surgical treatment was ineffective. We suspected hereditary neuralgic amyotrophy because of enlargement distal to the brachial plexus on MRI and administered steroid therapy, after which the weakness improved. Genetic testing revealed a point mutation in SEPT9. Because lesions outside the brachial plexus can be seen in hereditary neuralgic amyotrophy, the diagnosis should be based on typical characteristics and the family history.

Peripheral Nerve Ultrasound for the Differentiation between ALS, Inflammatory, and Hereditary Polyneuropathies

Background and Objectives: Ultrasound (US) is a non-invasive tool for the in vivo detection of peripheral nerve alterations. Materials and Methods: In this study, we applied nerve US to assist the discrimination between the spectrum of amyotrophic lateral sclerosis (ALS, n = 11), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP, n = 5), and genetically confirmed Charcot-Marie-Tooth disease (CMT, n = 5). All participants and n = 15 controls without neurological diseases underwent high-resolution US of the bilateral tibial nerve. The nerve cross-sectional area (CSA) and nerve microvascular blood flow were compared between the groups and related to cerebrospinal fluid (CSF) measures, clinical symptoms, and nerve conduction studies. The analyses are part of a larger multimodal study on the comparison between US and 7 Tesla (7T) magnetic resonance neurography (MRN). Results: The patients and controls were matched with respect to their demographical data. CMT had the longest disease duration, followed by CIDP and ALS. CSA was related to age, weight, and disease duration. CSA was larger in CMT and CIDP compared to ALS and controls. The blood flow was greatest in CIDP, and higher than in CMT, ALS, and controls. In ALS, greater CSA was correlated with greater CSF total protein and higher albumin quotient. The US measures did not correlate with clinical scores or nerve conduction studies in any of the subgroups. Conclusion: Our results point towards the feasibility of CSA and blood flow to discriminate between ALS, CIDP, and CMT, even in groups of small sample size. In ALS, larger CSA could indicate an inflammatory disease subtype characterized by reduced blood-nerve barrier integrity. Our upcoming analysis will focus on the additive value of 7T MRN in combination with US to disentangle the spectrum between more inflammatory or more degenerative disease variants among the disease groups.

Red Flags for Chronic Inflammatory Demyelinating Polyradiculoneuropathy Associated with Sarcoidosis or Connective Tissue Diseases

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system. Diagnosis relies on clinical and electrophysiological criteria. Various disorders requiring specific treatment regimens may be associated with CIDP, including sarcoidosis (SAR-CIDP) and connective tissue disease (CTD-CIDP). Therefore, it is important to distinguish between CIDP, SAR-CIDP and CTD-CIDP. In this retrospective monocentric study, we analyzed 16 patients with SAR-CIDP and 11 with CTD-CIDP and compared them with a group of 17 patients with idiopathic CIDP. SAR-CIDP patients had a frequently acute or subacute CIDP onset. CTD-CIDPs were mostly Sjögren's syndrome and lupus, and patients had a chronic onset. An older age at onset (64.5 vs. 54 years, p = 0.04), more atypical presentation (19/25 (76%) vs. 6/17 (35%), p = 0.008), acute/subacute onset of symptoms (15/25 (60%) vs. 1/17 (6%), p = 0.0004) and more frequent weight loss (7/16 (44%) vs. 0/17 (0%), p = 0.017) were identified SAR-CIDP and CTD-CIDP groups. Response to intravenous immunoglobulin therapy was lower in the combined SAR-CIDP and CTD-CIDP group (44% versus 82%, p = 0.005). As sarcoidosis and CTDs might be associated with CIDP and require specific management, the "red flags" mentioned above should be kept in mind by clinicians managing patients with CIDP.

Evaluating Diagnostic Ultrasound of the Vagus Nerve as a Surrogate Marker for Autonomic Neuropathy in Diabetic Patients

Background and Objectives: Diagnostic ultrasound of the vagus nerve has been used to examine different polyneuropathies, and it has been suggested to be useful as a marker of autonomic dysfunction in diabetic patients. Materials and Methods: We analyzed the cross-sectional area (CSA) of the right vagus nerve of 111 patients with type 2 diabetes in comparison to 104 healthy adults and 41 patients with CIDP (chronic inflammatory demyelinating polyneuropathy). In the diabetes group, sympathetic skin response (SSR) was measured as an indicator for autonomic neuropathy. Carotid intima-media thickness (CIMT) was measured as a surrogate for atherosclerosis. Clinical symptoms of polyneuropathy were assessed using the Neuropathy Symptom Score and the Neuropathy Disability Score. Results: In total, 61.3% of the diabetes patients had clinical signs of polyneuropathy; 23.4% had no SSR at the feet as an indicator of autonomic neuropathy. Mean vagus nerve CSA did not differ in patients with and without diabetic polyneuropathy or in diabetic patients with and without SSR at the feet. No significant correlation was found between vagus nerve CSA and CIMT or SSR parameters in diabetic patients. Mean CSA of the right vagus nerve was slightly larger in diabetic patients (p = 0.028) and in patients with CIDP (p = 0.015) than in healthy controls. Conclusions: Effect sizes and mean differences were rather small so that a reliable diagnosis cannot be performed based on the vagus nerve measurement of a single person alone. Vagus nerve CSA seems not suitable as an indicator of autonomic dysfunction or cardiovascular risk in diabetic patients.

Prevalence and associated factors with peripheral neuropathies in the general population in the rural area of Adjohoun in Benin

BACKGROUND

Peripheral neuropathies (PN) are a group of neurological conditions related to damage to the peripheral nervous system. Due to their wide diversity, few studies in sub-Saharan Africa have explored their epidemiology in general population. Our objective was to study the prevalence and associated factors with PN in general population in Adjohoun in Benin.

METHODS

A cross-sectional study has been conducted from February to March 2019 and included people aged ≥ 18 years old living in Adjohoun, Benin. Following a screening phase for PN (using World Health Organization questionnaire for major neurological diseases), a neurologist made a diagnosis after in-depth clinical examinations completed in some cases by electroneuromyography. The EFNS (European Federation of Neurological Societies) 2010 criteria was used for chronic inflammatory demyelinating polyneuropathy diagnosis. Data such as age, occupation, consanguinity, alcohol consumption, diabetes, hypertension were collected. Association between independent variables and PN were investigated using multivariable logistic regression models.

RESULTS

In total, 1 655 participants were included, mean age 41.4 ± 16.7 years; 64.8 % are female. The overall prevalence of PN was 6.9 % (95 %CI: 5.7 %-8.2 %). The main types of PN were: polyneuropathies 4.8 % (95 %CI: 3.8 %-5.9 %); polyradiculoneuropathies 1.6 % (95 %CI: 1.0 %-2.2 %). Factors independently associated with PN were age ≥ 40 years (adjusted Odds Ratio aOR = 19.6; 95 %CI: 8.2-46.3), diabetes (aOR = 1.8; 95 %CI: 1.08-2.99) and hypertension (aOR = 1.6; 95 %CI: 1.02-2.5).

CONCLUSION

The prevalence of PN was high in the rural commune of Adjohoun in Benin. Actions on its modifiable associated factors such as diabetes and hypertension could help reduce the proportion of PN and their potential harmful consequences.

The effect of tremor on disability assessment in chronic inflammatory demyelinating polyradiculoneuropathy

Tremor in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is common, often unresponsive to treatment, and may contribute to disability. We aim to investigate whether tremor is associated with disability as measured in daily practice and clinical trials, independent of other impairments. We included 76 CIDP patients in this cross-sectional study. We assessed tremor with the Tremor Research Group essential tremor rating assessment scale (TETRAS) and the Fahn-Tolosa-Marin clinical rating scale (FTM). Disability was measured with the inflammatory Rasch-built overall disability scale (I-RODS) and the adjusted Inflammatory Neuropathy Cause and Treatment disability scale (INCAT-DS, categorized separately in arm score, or total score). Impairments including strength, sensory impairment, and fatigue were measured using specific impairment scales. We tested whether "the presence of a clinically relevant tremor" (based on TETRAS and FTM) or "tremor severity" (FTM part B sum score) was associated with disability scores (I-RODS, INCAT-DS total score, and INCAT-DS arm score), independent of the impairment scores, using multivariate regression. Both "the presence of a clinically relevant tremor" and "tremor severity" were significantly associated with disability measured by the INCAT-DS (arm score and total score), but not the I-RODS, independent of strength, sensory impairment, and fatigue. The explained variances were low. Clinically relevant tremor can (partly) explain disability in CIDP, as measured with the INCAT-DS, independent of muscle strength, sensory deficits, and fatigue. To assess disease activity in CIDP patients with tremor, both impairment and disability outcomes should be assessed, as disability is caused partly by tremor while the effect of immunotherapy on tremor seems limited.

A Budget Impact Model of Maintenance Treatment of Chronic Inflammatory Demyelinating Polyneuropathy with IgPro20 (Hizentra) Relative to Intravenous Immunoglobulin in the United States

BACKGROUND

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare, progressive autoimmune disease causing peripheral nervous system dysfunction. Guidelines recommend immunoglobulin (IG) therapy as an immunomodulatory agent in CIDP. Drawbacks and unmet needs with intravenous immunoglobulin (IVIG) include adverse effects and wear-off effects, along with the burden of administration based on site of care. Subcutaneous administration of Hizentra, a subcutaneous immunoglobulin (SCIG) reduces patient burden by allowing self-administration outside the hospital setting and has fewer adverse events (AEs).

OBJECTIVE

We aimed to compare the expected cost of treatment and the budget impact of Hizentra compared with IVIG for maintenance treatment of CIDP in the United States.

METHODS

A decision tree model was developed to estimate the expected budget impact of maintenance treatment with Hizentra for US stakeholders. The model adopts primarily a US integrated delivery network perspective and, secondarily, a commercial perspective over a 1-year time horizon. Pharmacy costs were based on a payment mix of average sales price (73%), wholesale acquisition cost (2%), and average wholesale price (25%). Costs in the model reflect 2022 US dollars. In accordance with the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines and recommendations for budget impact modeling, no discounting was performed. The PATH clinical study of Hizentra maintenance in CIDP was used to determine clinical inputs for relapse rates at initial assessment (24 weeks) and at 52 weeks for Hizentra. The ICE clinical study of Gamunex maintenance in CIDP was the basis of relapse rates for Gamunex (and other IVIGs). Literature-based estimates were obtained for infusion costs by site of care, costs of IVIG infusion-related complications, and significant IVIG AE rates. Hizentra AE rates from the US Hizentra prescribing information were assessed but were not included in the model as the AEs in CIDP were mild, easily treated, and self-limited. Sensitivity analyses and scenario analyses were conducted to evaluate variations from the base case.

RESULTS

The model showed that a Hizentra starting dose of 0.2 g/kg is expected to result in annual cost savings of US$32,447 per patient compared with IVIG. For a hypothetical 25-million-member plan, the budget impact of a 10% market share shift from IVIG to Hizentra is expected to result in savings of US$2,296,235.

CONCLUSION

This analysis projects that Hizentra is likely associated with favorable economic benefit compared with IVIG in managing CIDP.

Needle electromyography abnormalities in the upper trapezius muscle in neuromuscular disorders

BACKGROUND

: Needle electromyography (EMG) abnormalities in the trapezius muscle (TM) can be seen in neuromuscular disorders. The aim was to determine the characteristics of needle EMG abnormalities observed in the TM in neuromuscular disorders.

METHODS

The data of patients who applied to the Clinical Neurophysiology Laboratory of University of Health Sciences Adana City Training and Research Hospital between December 2018 and October 2021 were reviewed. Polio survivors, amyotrophic lateral sclerosis (ALS) patients, patients with sensorimotor polyneuropathy, patients with spinal cord lesions involving C2/C3/C4 segments, patients with spinal accessory nerve (SAN) lesions, neuralgic amyotrophy (NA) patients, and patients with myopathy were included. Needle EMG findings of the upper TM of the patients were analyzed. Positive sharp waves, fibrillation potentials, fasciculation potentials, myotonic discharges, and motor unit action potential (MUAP) changes were considered needle EMG abnormalities.

RESULTS

Eighty-one polio survivors, 23 ALS patients, 39 patients with sensorimotor polyneuropathy, 10 patients with cervical spinal lesions, eight NA patients, seven patients with SAN lesions, and three patients with myopathy were included in the study. Fifteen (65.2%) ALS patients, 18 (22.2%) polio survivors, three (30%) patients with cervical spinal lesions, two (5.1%) patients with sensorimotor neuropathy, one (12.5%) NA patient, seven (100%) patients with SAN lesions, and two (66.7%) patients with myopathies had at least one needle EMG abnormality in the TM. Fasciculation potentials in the TM were seen in 10 (43.5%) ALS patients. In four patients with SAN lesions and one polio survivor, MUAP could not be obtained from the TM.

DISCUSSION

There may be more frequent needle EMG abnormalities, particularly in ALS patients and patients with SAN lesions. Since the number of patients with myopathy included in this study was low, it is difficult to comment on the needle EMG features of the TM for these patients. In addition, this study indicated that fasciculation potentials in the TM are typical in ALS patients and that MUAP may not be obtained from the TM in patients with SAN lesions.

On the path to evidence-based therapy in neuromuscular disorders

Neuromuscular disorders encompass a diverse group of acquired and genetic diseases characterized by loss of motor functionality. Although cure is the goal, many therapeutic strategies have been envisioned and are being studied in randomized clinical trials and entered clinical practice. As in all scientific endeavors, the successful clinical translation depends on the quality and translatability of preclinical findings and on the predictive value and feasibility of the clinical models. This chapter focuses on five exemplary diseases: childhood spinal muscular atrophy (SMA), Charcot-Marie-Tooth (CMT) disorders, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), acquired autoimmune myasthenia gravis (MG), and Duchenne muscular dystrophy (DMD), to illustrate the progress made on the path to evidenced-based therapy.

Standardized Tapering off Subcutaneous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy

BACKGROUND

Attempting discontinuation of treatment in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) is recommended. However, there is no evidence based regimen for tapering off subcutaneous immunoglobulin (SCIG). This trial investigated stepwise tapering off SCIG to detect remission and the lowest effective dosage. During tapering off, frequent vs less frequent clinical evaluation was compared.

METHODS

Patients with CIDP receiving a stable SCIG dosage followed a standardized tapering off regimen: 90%, 75%, 50%, 25% and 0% of the initial dose every 12th week, pending no deterioration occurred. In case of relapse during tapering off, the lowest effective dose was identified. Treatment with SCIG was registered for two years after participation. Disability score and grip strength were primary parameters. Participants were randomized to clinical evaluation every 6th week (frequent) or 12th week (less frequent).

RESULTS

Fifty-five patients were included of which thirty-five relapsed. Twenty patients (36%) were able to discontinue treatment without relapse. In relapsing patients, median dosage could be reduced by 10% (range, 0-75). After two years, 18 of 20 patients were still in remission without treatment. Frequent clinical evaluation did not detect deterioration more frequently than less frequent evaluation; RR 0.5 (95% CI, 0.2-1.2) (p = 0.17).

CONCLUSION

In stable CIDP patients, SCIG could be completely tapered off in 36% of the patients and only in 10% of these patients relapse occurred during the following two years. More frequent evaluation was not superior to detect deterioration.

Hereditary transthyretin amyloidosis overview

Hereditary amyloidogenic transthyretin (ATTRv) amyloidosis is a rare autosomal dominantly inherited disorder caused by mutations in the transthyretin (TTR) gene. The pathogenetic model of ATTRv amyloidosis indicates that amyloidogenic, usually missense, mutations destabilize the native TTR favouring the dissociation of the tetramer into partially unfolded species that self-assemble into amyloid fibrils. Amyloid deposits and monomer-oligomer toxicity are the basis of multisystemic ATTRv clinical involvement. Peripheral nervous system (autonomic and somatic) and heart are the most affected sites. In the last decades, a better knowledge of pathomechanisms underlying the disease led to develop novel and promising drugs that are rapidly changing the natural history of ATTRv amyloidosis. Thus, clinicians face the challenge of timely diagnosis for addressing patients to appropriate treatment. As well, the progressive nature of ATTRv raises the issue of presymptomatic testing and risk management of carriers. The main aim of this review was to focus on what we know about ATTRv so far, from pathogenesis to clinical manifestations, diagnosis and hence patient's monitoring and treatment, and from presymptomatic testing to management of carriers.

Update on therapy of chronic immune-mediated neuropathies

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

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.

Intravenous immunoglobulin in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP): mechanisms of action and clinical and genetic considerations

INTRODUCTION

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune peripheral nerve disorder that is characterized by subacute onset, progressive or relapsing weakness, and sensory deficits. Proven treatments include intravenous immunoglobulin (IVIg), corticosteroids, and plasma exchange. This review focuses on the mechanisms of action, pharmacodynamics, genetic variations, and disease characteristics that can affect the efficacy of IVIg.

AREAS COVERED

The proposed mechanisms of action of IVIg that can mediate its therapeutic effects are reviewed. These include anti-idiotypic interactions, inhibition of neonatal Fc receptors (FcRn), anti-complement activity, upregulation of inhibitory FcγRIIB receptors, and downregulation of macrophage activation or co-stimulatory and adhesion molecules. Clinical and genetic factors that can affect the therapeutic response include misdiagnosis, degree of axonal damage, pharmacokinetic variability, and genetic variations.

EXPERT OPINION

The mechanisms of action of IVIg in CIDP and their relative contribution to its efficacy are subject of ongoing investigation. Studies in other autoimmune neurological conditions, in addition, highlight the role of key immunopathological pathways and factors that are likely to be affected. Further investigation into the pathogenesis of CIDP and the mechanisms of action of IVIg may lead to the development of improved diagnostics, better utilization of IVIg, and more targeted and effective therapies.

French recommendations for the management of adult & pediatric chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system, primarily affecting the myelin sheath. The pathophysiology of CIDP is complex, involving both humoral and cellular immunity. The diagnosis of CIDP should be suspected in patients with symmetrical proximal and distal motor weakness and distal sensory symptoms of progressive onset, associated with decreased/abolished tendon reflexes. Treatments include intraveinous immunoglobulins, steroids and plasma exchange, with usually an induction phase followed by a maintenance therapy with progressive weaning. Treatment should be rapidly initiated to prevent axonal degeneration, which may compromise recovery. CIDP outcome is variable, ranging from mild distal paresthesiae to complete loss of ambulation. There have been several breakthroughs in the diagnosis and management of CIDP the past ten years, e.g. discovery of antibodies against the node of Ranvier, contribution of nerve ultrasound and magnetic resonance imaging to diagnosis, and demonstration of subcutaneous immunoglobulins efficiency. This led us to elaborate French recommendations for the management of adult & pediatric CIDP patients. These recommendations include diagnosis assessment, treatment, and follow-up.

A Bioelectrical Impedance Analysis for the Assessment of Muscle Atrophy in Patients with Chronic Inflammatory Demyelinating Polyneuropathy

Objective Muscle atrophy is observed in a subset of patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Its manifestation is associated with a poor functional prognosis and poor response to immunomodulatory therapies. We evaluated muscle atrophy in patients with CIDP using a bioelectrical impedance analysis (BIA). Methods We enrolled 12 patients with CIDP for a BIA of muscle atrophy. Of these 12 patients, 10 were diagnosed with typical CIDP, 1 with multifocal acquired demyelinating sensory and motor neuropathy, and 1 with distal acquired demyelinating symmetric neuropathy. All 12 patients underwent a series of assessments and evaluations, including a BIA and computed tomography (CT). A correlation was found between the skeletal muscle mass determined by the BIA and that found using CT of the muscles. Results The BIA provided values for each patient's skeletal muscle mass index (SMI) ranging from 4.1 to 8.1 kg/m². Four of the patients with CIDP had SMI values below the threshold for sarcopenia. CT of the patients' muscles provided scores indicating grades of muscle atrophy in the upper and lower extremities. A comparison of the outcomes from these two measures showed a good correlation between their muscle atrophy ratings (p <0.05). Conclusions We found that a BIA and muscle CT provided muscle atrophy assessments of equivalent accuracy. Therefore, a BIA can be a simple alternative to muscle CT that is suitable for regular use in daily clinical practice as a reliable tool for assessing muscle atrophy in patients with CIDP.

A longitudinal evaluation of fatigue in chronic inflammatory demyelinating polyneuropathy

BACKGROUND AND AIMS

Fatigue is a common but poorly understood complaint in patients with immune-mediated polyneuropathies. We sought to evaluate changes in fatigue over 1 year in a cohort of chronic inflammatory demyelinating polyneuropathy (CIDP) patients and to correlate changes in fatigue with changes in disability and quality of life. Investigation into other factors that may contribute to fatigue with a particular interest in the role other chronic disease states may play was also performed.

METHODS

Fifty patients with CIDP who satisfied the 2010 EFNS/PNS diagnostic criteria were followed over the period of 1 year at three tertiary care centers in Serbia. Assessments of disability, quality of life, and patient perception of change and fatigue were collected at two time points 12 months apart. Comorbidities, treatment regimens, and sedating medication use was collected.

RESULTS

Disability, quality of life, and patient perception of change showed statistically significant correlations with change in fatigue (p < .01). Increased levels of fatigue were noted in patients who used sedating medications (p = .05) and who had a comorbid chronic medical condition (p = .01).

INTERPRETATION

Worsening fatigue correlates over time with increased disability and worse quality of life. Fatigue is not specific to CIDP, but is common in many chronic medical conditions and with the use of sedating medications. Our findings support the importance of identifying and supportively managing fatigue in patients with CIDP, but cautions against considering fatigue as a CIDP diagnostic symptom or using fatigue to justify immunotherapy utilization.

Myoclonus and tremor in chronic inflammatory demyelinating polyneuropathy: a multichannel electromyography analysis

BACKGROUND

Information regarding involuntary movements in chronic inflammatory polyneuropathy (CIDP) is gradually increasing. Our goal is to identify the types of involuntary movements in CIDP.

METHODS

All patients who were followed with the diagnosis of CIDP were invited for clinical and electrophysiological evaluations. Demographic and clinical findings (age, gender, duration of illness, diagnosis, treatments) were noted. Clinical examination and multichannel surface electromyography were done. We also performed routine upper and lower extremity peripheral nerve conduction studies, F-waves, long latency reflexes, blink reflex, mixed nerve silent period and cutaneous silent period in all patients.

RESULTS

Twenty-two patients accepted the invitation. Eleven patients with CIDP had involuntary movements. Ten (45.5%) patients with CIDP had tremor and seven (31.8%) had short-duration and high-amplitude myoclonus. Regarding demographic, clinical and electrophysiological features, there was no significant difference between patients with and without tremor. The latencies of R1, R2 and R2c components of BR were longer among CIDP patients without tremor compared to CIDP patients with tremor. Presence of myoclonus (p = 0.007) and delayed F-waves (p = 0.008) were associated with the presence of tremor.

CONCLUSION

Tremor and myoclonus were frequent in CIDP. The fact that myoclonus was detected in the majority of patients only by multichannel surface EMG who were clinically evaluated as pure tremor suggests that a more detailed electrophysiological evaluation is required. There was no difference in the medications used or other clinical features between patients with and without tremor.

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

OBJECTIVE

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

RESULTS

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

CONCLUSIONS

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

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) in Diabetes Mellitus: A Diagnostic Dilemma

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a neurological disorder of the peripheral nerves which can lead to gradually increasing motor and sensory loss. It can be a difficult entity to diagnose, particularly in elderly patients with a history of Diabetes Mellitus due to their overlapping neuropathic syndromes. Reported is a case of CIDP in an elderly female who manifested multiple sensory, motor, and autonomic complaints. A compilation of clinical features, neuroimaging, lumbar puncture, electromyography, nerve conduction studies, and nerve biopsy were used to reach the diagnosis. Highlighted is a clinical approach to identifying CIDP that can cause neuropathy in the setting of other potential confounding disorders namely Diabetes Mellitus. 

[Clinical and long-term characteristics of the subtypes of chronic inflammatory demyelinating polyneuropathy]

OBJECTIVE

To clarify the clinical and long-term characteristic of each subtype of chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

We evaluated data from 30 consecutive CIDP patients who met the criteria proposed by the European Federation of Neurological Societies and the Peripheral Nerve Society.

RESULTS

Patients were classified as having typical CIDP (t-‍CIDP) (10/30, 33%), multifocal acquired demyelinating sensory and motor (MADSAM) (12/30, 40%), DADS (4/30, 13%), sensory CIDP (3/30, 10%) or motor CIDP (1/30, 3%). Nerve conduction studies showed more prolonged distal motor latencies/F-wave latencies and slower motor nerve conduction in the typical CIDP group than in the MADSAM group. Intravenous immunoglobulin (IVIg) was effective in 80% (8/10) of t-‍CIDP, 100% (12/12) of MADSAM, 100% (4/4) of DADS, and 100% (3/3) of sensory CIDP cases. Maintenance therapy with immunoglobulin was administered in patients with t-‍CIDP (5/10, 50%), MADSAM (9/12, 75%), DADS (1/4, 25%), and sensory CIDP (2/3, 67%). There were no patients with CIDP, in whom CIDP subtype was transformed from the initial diagnosis during five years of follow-up.

DISCUSSION

Percentage of MADSAM was the most common phenotype in our cohort of CIDP patients, and IVIg/immunoglobulin maintenance was effective for MADSAM as well as t-‍CIDP in contrast to findings from the previous reports.

Clinical and diagnostic features of anti-neurofascin-155 antibody-positive neuropathy in Han Chinese

Objective

To investigate the clinical features of Han Chinese patients with anti‐neurofascin‐155 (NF155) antibody‐positive neuropathy.

Methods

We screened 194 patients with peripheral neuropathy for NF155 antibodies using a cell‐based assay (CBA) and teased‐fiber immunofluorescence assay. We summarized the clinical findings of seropositive patients.

Results

The sera from 17 patients reacted to human embryonic kidney 293 cells transfected with NF155. Eleven of these patients had the immunoglobulin G (IgG) 4 isotype, a younger onset age, tremor, higher levels of cerebrospinal fluid protein, a larger diameter of the lumbosacral nerve root on magnetic resonance imaging, and the distal demyelinating symmetric phenotype. Most patients responded to steroids and rituximab. For the remaining six seropositive patients in CBA, the predominant antibody isotype was IgG3, IgG1, or undetectable, and only one patient with IgG3 showed a positive result in the teased‐fiber immunofluorescence assay. These patients did not share the typical features displayed by patients with the IgG4 isotype.

Interpretation

In the Han Chinese population, a significant proportion of patients who fulfilled the criteria for chronic inflammatory demyelinating polyradiculoneuropathy diagnosis had anti‐NF155 IgG4 antibody‐positive neuropathy and displayed specific phenotypes. Ambiguous staining patterns may appear, and the potential for false positivity should be considered. For patients who presented with specific phenotypes, identifying antibodies and subtypes involved a significant laboratory workup.