Intravenous immunoglobulin for multifocal motor neuropathy

Current and Emerging Pharmacotherapeutic Interventions for the Treatment of Peripheral Nerve Disorders

Peripheral nerve disorders are caused by a range of different aetiologies. The range of causes include metabolic conditions such as diabetes, obesity and chronic kidney disease. Diabetic neuropathy may be associated with severe weakness and the loss of sensation, leading to gangrene and amputation in advanced cases. Recent studies have indicated a high prevalence of neuropathy in patients with chronic kidney disease, also known as uraemic neuropathy. Immune-mediated neuropathies including Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy may cause significant physical disability. As survival rates continue to improve in cancer, the prevalence of treatment complications, such as chemotherapy-induced peripheral neuropathy, has also increased in treated patients and survivors. Notably, peripheral neuropathy associated with these conditions may be chronic and long-lasting, drastically affecting the quality of life of affected individuals, and leading to a large socioeconomic burden. This review article explores some of the major emerging clinical and experimental therapeutic agents that have been investigated for the treatment of peripheral neuropathy due to metabolic, toxic and immune aetiologies.

Immunoglobulin for multifocal motor neuropathy

BACKGROUND

Multifocal motor neuropathy (MMN) is a rare, probably immune-mediated disorder characterised by slowly progressive, asymmetric, distal weakness of one or more limbs with no objective loss of sensation. It may cause prolonged periods of disability. Treatment options for MMN are few. People with MMN do not usually respond to steroids or plasma exchange. Uncontrolled studies have suggested a beneficial effect of intravenous immunoglobulin (IVIg). This is an update of a Cochrane Review first published in 2005, with an amendment in 2007. We updated the review to incorporate new evidence.

OBJECTIVES

To assess the efficacy and safety of intravenous and subcutaneous immunoglobulin in people with MMN.

SEARCH METHODS

We searched the following databases on 20 April 2021: the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and WHO ICTRP for randomised controlled trials (RCTs) and quasi-RCTs, and checked the reference lists of included studies.

SELECTION CRITERIA

We considered RCTs and quasi-RCTs examining the effects of any dose of IVIg and subcutaneous immunoglobulin (SCIg) in people with definite or probable MMN for inclusion in the review. Eligible studies had to have measured at least one of the following outcomes: disability, muscle strength, or electrophysiological conduction block. We used studies that reported the frequency of adverse effects to assess safety.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the literature searches to identify potentially relevant trials, assessed risk of bias of included studies, and extracted data. We followed standard Cochrane methodology.

MAIN RESULTS

Six cross-over RCTs including a total of 90 participants were suitable for inclusion in the review. Five RCTs compared IVIg to placebo, and one compared IVIg to SCIg. Four of the trials comparing IVIg versus placebo involved IVIg-naive participants (induction treatment). In the other two trials, participants were known IVIg responders receiving maintencance IVIg at baseline and were then randomised to maintenance treatment with IVIg or placebo in one trial, and IVIg or SCIg in the other. Risk of bias was variable in the included studies, with three studies at high risk of bias in at least one risk of bias domain. IVIg versus placebo (induction treatment): three RCTs including IVIg-naive participants reported a disability measure. Disability improved in seven out of 18 (39%) participants after IVIg treatment and in two out of 18 (11%) participants after placebo (risk ratio (RR) 3.00, 95% confidence interval (CI) 0.89 to 10.12; 3 RCTs, 18 participants; low-certainty evidence). The proportion of participants with an improvement in disability at 12 months was not reported. Strength improved in 21 out of 27 (78%) IVIg-naive participants treated with IVIg and one out of 27 (4%) participants who received placebo (RR 11.00, 95% CI 2.86 to 42.25; 3 RCTs, 27 participants; low-certainty evidence). IVIg treatment may increase the proportion of people with resolution of at least one conduction block; however, the results were also consistent with no effect (RR 7.00, 95% CI 0.95 to 51.70; 4 RCTs, 28 participants; low-certainty evidence). IVIg versus placebo (maintenance treatment): a trial that included participants on maintenance IVIg treatment reported an increase in disability in 17 out of 42 (40%) people switching to placebo and seven out of 42 (17%) remaining on IVIg (RR 2.43, 95% CI 1.13 to 5.24; 1 RCT, 42 participants; moderate-certainty evidence) and a decrease in grip strength in 20 out of 42 (48%) participants after a switch to placebo treatment compared to four out of 42 (10%) remaining on IVIg (RR 0.20, 95% CI 0.07 to 0.54; 1 RCT, 42 participants; moderate-certainty evidence). Adverse events, IVIg versus placebo (induction or maintenance): four trials comparing IVIg and placebo reported adverse events, of which data from two studies could be meta-analysed. Transient side effects were reported in 71% of IVIg-treated participants versus 4.8% of placebo-treated participants in these studies. The pooled RR for the development of side effects was 10.33 (95% CI 2.15 to 49.77; 2 RCTs, 21 participants; very low-certainty evidence). There was only one serious side effect (pulmonary embolism) during IVIg treatment. IVIg versus SCIg (maintenance treatment): the trial that compared continuation of IVIg maintenance versus SCIg maintenance did not measure disability. The evidence was very uncertain for muscle strength (standardised mean difference 0.08, 95% CI -0.84 to 1.00; 1 RCT, 9 participants; very low-certainty evidence). The evidence was very uncertain for the number of people with side effects attributable to treatment (RR 0.50, 95% CI 0.18 to 1.40; 1 RCT, 9 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Low-certainty evidence from three small RCTs shows that IVIg may improve muscle strength in people with MMN, and low-certainty evidence indicates that it may improve disability; the estimate of the magnitude of improvement of disability has wide CIs and needs further studies to secure its significance. Based on moderate-certainty evidence, it is probable that most IVIg responders deteriorate in disability and muscle strength after IVIg withdrawal. SCIg might be an alternative treatment to IVIg, but the evidence is very uncertain. More research is needed to identify people in whom IVIg withdrawal is possible and to confirm efficacy of SCIg as an alternative maintenance treatment.

One nerve suffices: A clinically guided nerve ultrasound protocol for the differentiation of multifocal motor neuropathy (MMN) and amyotrophic lateral sclerosis (ALS)

OBJECTIVE

To investigate diagnostic accuracy of a nerve ultrasound (US) protocol that is individualized to a patient's clinical deficits for the differentiation of amyotrophic lateral sclerosis with predominant lower motoneuron disease (ALS/LMND) and multifocal motor neuropathy (MMN).

METHODS

Single-center, prospective, examiner-blinded, diagnostic study in two cohorts. Cohort I (model development): Convenience sample of subjects with ALS/LMND or MMN according to revised El-Escorial or EFNS guidelines. Cohort II (model validation): Consecutively recruited treatment-naïve subjects with suspected diagnosis of ALS/LMND or MMN. Cutoffs for 28 different US values were determined by Receiver Operating Curve (ROC) in cohort I. Area Under The Curve (AUC) of US was compared to nerve conduction studies (NCS). Diagnostic accuracy of US protocols, individualized according to clinical deficits, was compared to former rigid non-individualized protocols and to random examination site selection in cohort II.

RESULTS

48 patients were recruited. In cohort I (28 patients), US had higher ROC AUCs than NCS, US 0.82 (0.12) (mean (standard deviation)), NCS (compound muscle action potential (CMAP) 0.60 (0.09), p < .001; two-sided t-test). US models based on the nerve innervating the clinically most affected muscles had higher correct classification rates (CCRs, 93%) in cohort II than former rigid protocols (85% and 80%), or models with random measurement site selection (66% and 80%).

CONCLUSIONS

Clinically guided US protocols for differentiation of ALS/LMND from MMN increase diagnostic accuracy when compared to clinically unguided protocols. They also require less measurements sites to achieve this accuracy.

Small Fibre Involvement in Multifocal Motor Neuropathy Explored with Sudoscan: A Single-Centre Experience

Objective: Multifocal motor neuropathy (MMN) is a rare inflammatory neuropathy, clinically characterized by exclusive motor involvement. We wished to evaluate the possible presence of sensory dysfunction, including the evaluation of small fibres, after a long-term disease course. Patients and methods: seven MMN patients, regularly followed in our Neurology Department, underwent clinical evaluation, neurophysiological examination by nerve conduction studies (NCSs), and Sudoscan. We compared neurophysiological data with a group of patients with other disorders of the peripheral nervous system. Results: NCSs showed a reduction of sensory nerve action potential amplitude in 2/7 MMN patients. Sudoscan showed borderline electrochemical skin conductance (ESC) values in 3/7 MMN patients (two of them with abnormal sensory NCSs). Conclusions: Our results confirm that sensory involvement may be found in some MMN after a long-term disease course, and it could also involve the small fibres.

Prior distributions for variance parameters in a sparse-event meta-analysis of a few small trials

In rare diseases, typically only a small number of patients are available for a randomized clinical trial. Nevertheless, it is not uncommon that more than one study is performed to evaluate a (new) treatment. Scarcity of available evidence makes it particularly valuable to pool the data in a meta-analysis. When the primary outcome is binary, the small sample sizes increase the chance of observing zero events. The frequentist random-effects model is known to induce bias and to result in improper interval estimation of the overall treatment effect in a meta-analysis with zero events. Bayesian hierarchical modeling could be a promising alternative. Bayesian models are known for being sensitive to the choice of prior distributions for between-study variance (heterogeneity) in sparse settings. In a rare disease setting, only limited data will be available to base the prior on, therefore, robustness of estimation is desirable. We performed an extensive and diverse simulation study, aiming to provide practitioners with advice on the choice of a sufficiently robust prior distribution shape for the heterogeneity parameter. Our results show that priors that place some concentrated mass on small τ values but do not restrict the density for example, the Uniform(-10, 10) heterogeneity prior on the log(τ² ) scale, show robust 95% coverage combined with less overestimation of the overall treatment effect, across varying degrees of heterogeneity. We illustrate the results with meta-analyzes of a few small trials.

Multifocal motor neuropathy: controversies and priorities

Despite 30 years of research there are still significant unknowns and controversies associated with multifocal motor neuropathy (MMN) including disease pathophysiology, diagnostic criteria and treatment. Foremost relates to the underlying pathophysiology, specifically whether MMN represents an axonal or demyelinating neuropathy and whether the underlying pathophysiology is focused at the node of Ranvier. In turn, this discussion promotes consideration of therapeutic approaches, an issue that becomes more directed in this evolving era of precision medicine. It is generally accepted that MMN represents a chronic progressive immune-mediated motor neuropathy clinically characterised by progressive asymmetric weakness and electrophysiologically by partial motor conduction block. Anti-GM1 IgM antibodies are identified in at least 40% of patients. There have been recent developments in the use of neuromuscular ultrasound and MRI to aid in diagnosing MMN and in further elucidation of its pathophysiological mechanisms. The present Review will critically analyse the knowledge accumulated about MMN over the past 30 years, culminating in a state-of-the-art approach to therapy.

Nerve ultrasound improves detection of treatment-responsive chronic inflammatory neuropathies

OBJECTIVE

To examine the diagnostic accuracy of nerve ultrasound in a prospective cohort of consecutive patients with a clinical suspicion of chronic inflammatory neuropathies, including chronic inflammatory demyelinating polyneuropathy, Lewis-Sumner syndrome, and multifocal motor neuropathy, and to determine the added value in the detection of treatment-responsive patients.

METHODS

Between February 2015 and July 2018, we included 100 consecutive incident patients with a clinical suspicion of chronic inflammatory neuropathy. All patients underwent nerve ultrasound, extensive standardized nerve conduction studies (NCS), and other relevant diagnostic investigations. We evaluated treatment response using predefined criteria. A diagnosis of chronic inflammatory neuropathy was established when NCS were abnormal (fulfilling criteria of demyelination of the European Federation of Neurological Societies/Peripheral Nerve Society) or when the degree of nerve enlargement detected by sonography was compatible with chronic inflammatory neuropathy and there was response to treatment.

RESULTS

A diagnosis of chronic inflammatory neuropathy was established in 38 patients. Sensitivity and specificity of nerve ultrasound and NCS were 97.4% and 69.4% and 78.9% and 93.5%, respectively. The added value of nerve ultrasound in detection of treatment-responsive chronic inflammatory neuropathy was 21.1% compared to NCS alone.

CONCLUSIONS

Nerve ultrasound and NCS are complementary techniques with superior sensitivity in the former and specificity in the latter. Addition of nerve ultrasound significantly improves the detection of chronic inflammatory neuropathies. Therefore, it deserves a prominent place in the diagnostic workup of chronic inflammatory neuropathies.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that nerve ultrasound is an accurate diagnostic tool to detect chronic inflammatory neuropathies.

Improving Intravenous Immunoglobulin Dosing in Autoimmune Neuropathies

This symposium took place on Monday 24th June 2019, as part of the 2019 Peripheral Nerve Society (PNS) Annual Meeting in Genoa, Italy. Immune-mediated neuropathies such as Guillain–Barré Syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and multifocal motor neuropathy (MMN) are diverse inflammatory peripheral nerve disorders. International consensus guidelines recommend intravenous Ig (IVIG) as Level A for the treatment of GBS, CIDP, and MMN. Suggested induction doses of IVIG are 2 g/kg divided over 2–5 days, but maintenance doses are purposely less clearly defined and left up to the judgement of the clinician, depending upon the specific needs of the individual patient. Community-based neurologists treating patients with these rare inflammatory neuropathies may be unaware of optimal dosing regimens and patient response to treatment may therefore be inadequate. In this symposium, world-renowned experts in GBS, CIDP, and MMN shared their expertise and review of the literature to provide reasonable dosing regimens for neurologists who may rarely encounter these conditions.

Efficacy and Tolerability of Intravenous Immunoglobulin and Subcutaneous Immunoglobulin in Neurologic Diseases

PURPOSE

IV immunoglobulin (Ig) therapy has been widely used for the treatment of neurologic disorders, autoimmune diseases, immunodeficiency-related diseases, blood system diseases, and cancers. In this review, we summarize the efficacy and tolerability of IVIg and SCIg therapy in neurologic diseases.

METHODS

We summarized and analyzed the efficacy and tolerability of IVIg and SCIg in neurologic diseases, by analyzing the literature pertaining to the use of IVIg and SCIg to treat nervous system diseases.

FINDINGS

In clinical neurology practice, IVIg has been shown to be useful for the treatment of new-onset or recurrent immune diseases and for long-term maintenance treatment of chronic diseases. Moreover, IVIg may have applications in the management of intractable autoimmune epilepsy, paraneoplastic syndrome, autoimmune encephalitis, and neuromyelitis optica. SCIg is emerging as an alternative to IVIg treatment. Although SCIg has a composition similar to that of IVIg, the applications of this therapy are different. Notably, the bioavailability of SCIg is lower than that of IVIg, but the homeostasis level is more stable. Current studies have shown that these 2 therapies have pharmacodynamic equivalence.

IMPLICATIONS

In this review, we explored the efficacy of IVIg in the treatment of various neurologic disorders. IVIg administration still faces many challenges. Thus, it will be necessary to standardize the use of IVIg in the clinical setting. SCIg administration is a novel and feasible treatment option for neurologic and immune-related diseases, such as chronic inflammatory demyelinating polyradiculoneuropathy and idiopathic inflammatory myopathies. As our understanding of the mechanisms of action of IVIg improve, potential next-generation biologics can being developed.

Human immune globulin 10% with recombinant human hyaluronidase in multifocal motor neuropathy

Objective

The primary aim was to determine the safety of treatment with human immune globulin 10% with recombinant human hyaluronidase (fSCIg) compared to intravenous immunoglobulin (IVIg) in a prospective open-label study in patients with multifocal motor neuropathy (MMN).

Methods

Our study consisted of two phases: the IVIg phase (visits 1–3; 12 weeks), in which patients remained on IVIg treatment, and the fSCIg phase (visits 4–7; 36 weeks), in which patients received fSCIg treatment. After visit 3, IVIg was switched to an equivalent dose and frequency of fSCIg. Outcome measures were safety, muscle strength, disability and treatment satisfaction.

Results

Eighteen patients were enrolled in this study. Switching to fSCIg reduced the number of systemic adverse events (IVIg 11.6 vs. fSCIg 5.0 adverse events/per person-year, p < 0.02), and increased the number of local reactions at the injection site (IVIg 0 vs. fSCIg 3.3 local reactions/per person-year, p < 0.01). Overall, no significant differences in muscle strength and disability between fSCIg and IVIg were found. Treatment with fSCIg was perceived as optimal treatment option by 8 of the 17 patients (47.1%) and they continued with fSCIg after study closure because of improved independence and flexibility to administer treatment.

Conclusion

Treatment with fSCIg can be considered a safe alternative for patients with MMN on IVIg treatment. fSCIg could be a favorable option in patients who prefer self-treatment and more independency, and in patients who experience systemic adverse events on IVIg or have difficult intravenous access.

Electronic supplementary material

The online version of this article (10.1007/s00415-019-09475-x) contains supplementary material, which is available to authorized users.

Chronic Brachial Plexus Neuritis That Developed into Typical Neuralgic Amyotrophy and Positively Responded to Immunotherapy

Based on the hypothesis that autoimmunity plays a role in the pathogenesis of neuralgic amyotrophy (NA), immunotherapy is sometimes administered. Early intervention is recommended for a good prognosis. We herein report the case of a 55-year-old man who presented with neuralgia, weakness, and muscle atrophy in his right shoulder girdle and upper arm, which progressed for ten months following a marine sports accident. The patient was diagnosed with NA. His neurological deficits gradually improved after several courses of immunotherapy, suggesting that in addition to being effective for treating early-stage disease, immunotherapy may be effective for treating chronic cases.

IVIg for apparently autoimmune small-fiber polyneuropathy: first analysis of efficacy and safety

OBJECTIVES

Small-fiber polyneuropathy (SFPN) has various underlying causes, including associations with systemic autoimmune conditions. We have proposed a new cause; small-fiber-targeting autoimmune diseases akin to Guillain-Barré and chronic inflammatory demyelinating polyneuropathy (CIDP). There are no treatment studies yet for this 'apparently autoimmune SFPN' (aaSFPN), but intravenous immunoglobulin (IVIg), first-line for Guillain-Barré and CIDP, is prescribed off-label for aaSFPN despite very high cost. This project aimed to conduct the first systematic evaluation of IVIg's effectiveness for aaSFPN.

METHODS

With IRB approval, we extracted all available paper and electronic medical records of qualifying patients. Inclusion required having objectively confirmed SFPN, autoimmune attribution and other potential causes excluded. IVIg needed to have been dosed at ⩾1 g/kg/4 weeks for ⩾3 months. We chose two primary outcomes - changes in composite autonomic function testing (AFT) reports of SFPN and in ratings of pain severity - to capture objective as well as patient-prioritized outcomes.

RESULTS

Among all 55 eligible patients, SFPN had been confirmed by 3/3 nerve biopsies, 62% of skin biopsies, and 89% of composite AFT. Evidence of autoimmunity included 27% of patients having systemic autoimmune disorders, 20% having prior organ-specific autoimmune illnesses and 80% having ⩾1/5 abnormal blood-test markers associated with autoimmunity. A total of 73% had apparent small-fiber-restricted autoimmunity. IVIg treatment duration averaged 28 ± 25 months. The proportion of AFTs interpreted as indicating SFPN dropped from 89% at baseline to 55% (p ⩽ 0.001). Sweat production normalized (p = 0.039) and the other four domains all trended toward improvement. Among patients with pre-treatment pain ⩾3/10, severity averaging 6.3 ± 1.7 dropped to 5.2 ± 2.1 (p = 0.007). Overall, 74% of patients rated themselves 'improved' and their neurologists labeled 77% as 'IVIg responders'; 16% entered remissions that were sustained after IVIg withdrawal. All adverse events were expected; most were typical infusion reactions. The two moderate complications (3.6%) were vein thromboses not requiring discontinuation. The one severe event (1.8%), hemolytic anemia, remitted after IVIg discontinuation.

CONCLUSION

These results provide Class IV, real-world, proof-of-concept evidence suggesting that IVIg is safe and effective for rigorously selected SFPN patients with apparent autoimmune causality. They provide rationale for prospective trials, inform trial design and indirectly support the discovery of small-fiber-targeting autoimmune/inflammatory illnesses.

Brachial plexus magnetic resonance imaging differentiates between inflammatory neuropathies and does not predict disease course

OBJECTIVE

The main objective of this study was to evaluate the correlation between the distribution of brachial plexus magnetic resonance imaging (MRI) abnormalities and clinical weakness, and to evaluate the value of brachial plexus MRI in predicting disease course and response to treatment in multifocal motor neuropathy (MMN), Lewis-Sumner syndrome (LSS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Sixty-seven patients with an inflammatory neuropathy diagnosed at our tertiary referral center for neuromuscular diseases had undergone bilateral T2-weighted short tau inversion recovery (STIR) MRI of the brachial plexus. We obtained clinical follow-up data and scored all MRIs for abnormalities and the symmetry of their distribution.

RESULTS

Brachial plexus MRI abnormalities were detected in 45% of the patients. An abnormal MRI did not predict disease course in terms of patterns of weakness, sensory disturbances or response to treatment. Within the spectrum of radiological abnormalities, asymmetrical clinical syndromes, MMN and LSS were significantly associated with asymmetrical radiological abnormalities, whereas symmetrical abnormalities predominated in CIDP (p < .001, phi 0.791).

CONCLUSION

T2 STIR brachial plexus MRI abnormalities correspond with the distribution of neurological deficits in inflammatory neuropathies, but do not correlate with specific clinical characteristics, response to treatment or disease course.

High-dose Ig VENA is well tolerated and efficacious in patients with multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a rare, chronic, motor neuropathy that progressively impairs physical functioning and quality of life. Randomised controlled trials have shown that high-dose intravenous immunoglobulin (IVIg) is superior to placebo in improving muscle strength and disability, but many patients require periodic infusions to maintain long-term improvement. This observational, multicentre, retrospective study investigated the efficacy and tolerability of human normal immunoglobulin (Ig VENA) at high intravenous infusion rates in 20 MMN patients (14 male, 6 female). Thirty days after the first infusion, there was an improvement of at least 1 point in two muscles compared to baseline on the Medical Research Council (MRC) scale and of 1 point in the ONLS (Overall Neuropathy Limitation Scale) scale in 15 patients (75%) and 10 patients (50%), respectively; 45% improved on both scales. At 6 months, 100% of 12 patients had improved on the MRC and 79% of 14 patients had improved on the ONLS scale; 83% improved on both scales. All reported adverse drug reactions (ADR) were mild, transient and possibly related to the study drug. Four patients (20%) reported ADRs, three reported headache and one fever. There were no serious or unexpected ADRs. By confirming that high-dose Ig VENA is efficacious and well tolerated, this study adds to the evidence base for IVIg in MMN and potentially increases clinicians' and patients' choice of therapy.

Efficacy of Various Intravenous Immunoglobulin Therapy Protocols in Autoimmune and Chronic Inflammatory Disorders

Objective:

To determine the efficacy of various intravenous immunoglobulin (IVIG) protocols used in the treatment of autoimmune and chronic inflammatory disorders.

Data Sources:

Literature retrieval was accessed through MEDLINE (November 1984–March 2007) and a search was conducted using the term intravenous immunoglobulin. References cited in the selected articles were also reviewed.

Study Selection and Data Extraction:

Inclusion criteria for studies were (1) English language, (2) randomized controlled trials, (3) defined protocols, (4) a minimum of 15 patients, and (5) objective criteria provided to assess clinical outcomes and course.

Data Synthesis:

The therapeutic efficacy of IVIG therapy is well established, and defined protocols exist for treatment of Kawasaki disease, immune thrombocytopenic purpura, Guillain–Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and autoimmune mucocutaneous blistering diseases. In the absence of a defined protocol, studies have demonstrated that IVIG therapy is effective in the treatment of myasthenia gravis, dermatomyositis, stiff person syndrome, antineutrophil cytoplasmic antibody positive systemic vasculitides, Graves' ophthalmopathy, and certain forms of systemic lupus erythematosus. It might also be of benefit in some patients with relapsing–remitting multiple sclerosis. The outcomes are variable in these studies. In toxic epidermal necrolysis and Stevens–Johnson syndrome, use of IVIG has dramatically influenced clinical response and reduced mortality.

Conclusions:

The cumulative evidence suggests that the clinical outcomes observed are significantly influenced by the use of a defined protocol. There is a need for multicenter trials approved by the Food and Drug Administration to better define the role of IVIG in many disease states. Such studies would be able to establish the indications for use, optimal dose, frequency of infusions, duration of therapy, and need for gradual withdrawal versus sudden cessation. Defined protocols resulting from the study of a large cohort of patients often convince insurance companies to create policies that provide access to IVIG therapy.

The Importance of Rare Subtypes in Diagnosis and Treatment of Peripheral Neuropathy: A Review

IMPORTANCE

Peripheral neuropathy is a prevalent condition that usually warrants a thorough history and examination but has limited diagnostic evaluation. However, rare localizations of peripheral neuropathy often require more extensive diagnostic testing and different treatments.

OBJECTIVE

To describe rare localizations of peripheral neuropathy, including the appropriate diagnostic evaluation and available treatments.

EVIDENCE REVIEW

References were identified from PubMed searches conducted on May 29, 2015, with an emphasis on systematic reviews and randomized clinical trials. Articles were also identified through the use of the authors' own files. Search terms included common rare neuropathy localizations and their causes, as well as epidemiology, pathophysiology, diagnosis, and treatment.

FINDINGS

Diffuse, nonlength-dependent neuropathies, multiple mononeuropathies, polyradiculopathies, plexopathies, and radiculoplexus neuropathies are rare peripheral neuropathy localizations that often require extensive diagnostic testing. Atypical neuropathy features, such as acute/subacute onset, asymmetry, and/or motor predominant signs, are frequently present. The most common diffuse, nonlength-dependent neuropathies are Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and amyotrophic lateral sclerosis. Effective disease-modifying therapies exist for many diffuse, nonlength-dependent neuropathies including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and some paraprotein-associated demyelinating neuropathies. Vasculitic neuropathy (multiple mononeuropathy) also has efficacious treatment options, but definitive evidence of a treatment effect for IgM anti-MAG neuropathy and diabetic amyotrophy (radiculoplexus neuropathy) is lacking.

CONCLUSIONS AND RELEVANCE

Recognition of rare localizations of peripheral neuropathy is essential given the implications for diagnostic testing and treatment. Electrodiagnostic studies are an important early step in the diagnostic evaluation and provide information on the localization and pathophysiology of nerve injury.

Treatment of patients with multifocal motor neuropathy with immunoglobulins in clinical practice: the SIGNS registry

OBJECTIVES

The management of patients with multifocal motor neuropathy (MMN) under everyday clinical conditions has been insufficiently studied. We therefore collected comprehensive observational data on patients with MMN who received intravenous (IV) or subcutaneous (SC) immunoglobulins (IGs) as maintenance therapy.

METHODS

This was a prospective, noninterventional study (registry) in neurological centres (hospitals and offices) throughout Germany.

RESULTS

As of 1 December 2015, 80 patients with MMN were included (mean age 55.4 ± 9.8 years, 67% males, mean disease duration 10.7 ± 10.2 years). The affected limb regions were predominantly distal muscle groups of the upper extremities. On the inflammatory neuropathy cause and treatment (INCAT) scale, 94% of the patients had some disability in the arms and 61% in the legs. At inclusion, 98.8% received IVIG and 1.3% SCIG. Substantial variation was observed between IVIG treatment intervals (every 0.7 to 17.3 weeks) and dosage (0.2-2.1 g/kg body weight received during a single administration; mean monthly dosage, 0.9 g/kg body weight). However, the mean monthly dosage was steady over time. At 1-year follow up, improvement was seen in muscle strength, INCAT and quality of life (QoL) scores (SF-36 questionnaire).

CONCLUSIONS

The management of patients with MMN in everyday clinical practice demonstrates a wide range of absolute dosages and treatment intervals of IG, supporting the recommended practice of determining treatment dose on an individual patient basis. The improvements in muscle strength and reduction in disability, accompanied by increased QoL, strengthen the case for use of IG as a maintenance treatment for MMN.

Immunotherapy in Peripheral Neuropathies

Immunotherapy has been investigated in a small subset of peripheral neuropathies, including an acute one, Guillain-Barré syndrome, and 3 chronic forms: chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, and neuropathy associated with IgM anti-myelin-associated glycoprotein. Several experimental studies and clinical data are strongly suggestive of an immune-mediated pathogenesis. Either cell-mediated mechanisms or antibody responses to Schwann cell, compact myelin, or nodal antigens are considered to act together in an aberrant immune response to cause damage to peripheral nerves. Immunomodulatory treatments used in these neuropathies aim to act at various steps of this pathogenic process. However, there are many phenotypic variants and, consequently, there is a significant difference in the response to immunotherapy between these neuropathies, as well as a need to improve our knowledge and long-term management of chronic forms.

Peripheral neuropathies

Peripheral neuropathies are diseases of the peripheral nervous system that can be divided into mononeuropathies, multifocal neuropathies, and polyneuropathies. Symptoms usually include numbness and paresthesia. These symptoms are often accompanied by weakness and can be painful. Polyneuropathies can be divided into axonal and demyelinating forms, which is important for diagnostic reasons. Most peripheral neuropathies develop over months or years, but some are rapidly progressive. Some patients only suffer from mild, unilateral, slowly progressive tingling in the fingers due to median nerve compression in the wrist (carpal tunnel syndrome), while other patients can be tetraplegic, with respiratory insufficiency within 1-2 days due to Guillain-Barré syndrome. Carpal tunnel syndrome, with a prevalence of 5% and incidence of 1-2 per 1000 person-years, is the most common mononeuropathy. Population-based data for chronic polyneuropathy are relatively scarce. Prevalence is estimated at 1% and increases to 7% in persons over 65 years of age. Incidence is approximately 1 per 1000 person-years. Immune-mediated polyneuropathies like Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy are rare diseases, with an annual incidence of approximately 1-2 and 0.2-0.5 per 100 000 persons respectively. Most peripheral neuropathies are more prevalent in older adults and in men, except for carpal tunnel syndrome, which is more common in women. Diabetes is a common cause of peripheral neuropathy and is associated with both mono- and polyneuropathies. Among the group of chronic polyneuropathies, in about 20-25% no direct cause can be found. These are slowly progressive axonal polyneuropathies.

Human immune globulin infusion in the management of multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a debilitating and rare disease causing profound weakness with minimal to no sensory symptoms. Conduction block is frequently seen on electrodiagnostic testing. An immune-mediated pathology is suspected though the exact underlying pathophysiology has yet to be elucidated. The presence of anti-GM1 ganglioside IgM antibodies coupled with favorable response to intravenous and subcutaneous immunoglobulins supports a complement-mediated mechanism which leads to destruction of nerve tissue with probable predilection to the nodes of Ranvier. High-dose immunoglobulin currently is the only treatment with proven efficacy for MMN patients. Unfortunately, many patients experience decreased responsiveness to immunoglobulins over time, requiring higher and more frequent dosing. In this review, we will focus on the pharmacology, efficacy, safety, and tolerability of intravenous and subcutaneous immune globulin infusion for treatment of MMN.

The pathogenesis of multifocal motor neuropathy and an update on current management options

Multifocal motor neuropathy (MMN) is a rare and disabling disease. Several experimental studies and clinical data are strongly suggestive of an immune-mediated pathogenesis, although underlying mechanisms in MMN seem to be very specific, mainly because of the presence of IgM anti-GM1 serum antibodies and the dramatic response to intravenous immunoglobulins (IVIg). The origin of antiganglioside antibodies and the way in which they act at the molecular level remain unclear. Several studies have demonstrated the key role of complement activation in the underlying mechanisms of MMN, as well as in animal models of acute motor axonal neuropathy (AMAN). Deposition of the membrane attack complex may disrupt the architecture of the nodes of Ranvier and paranodal areas, causing local disruption of nodal sodium-channel clusters. In patients with MMN, muscle weakness is the consequence of conduction blocks (CB), which leads to secondary axonal degeneration, consequently the aim of the treatment is to reverse CB at early stages of the disease. High-dose immunoglobulin is to date the only therapy which has proven efficacy in MMN patients in providing transient improvement of muscle strength, but long-term follow-up studies show a progressive motor decline. Therefore, other therapies are needed to improve the conduction nerve properties in long-term design. The reduction of complement activation and more generally the gain in paranodal stabilization could be directions for future therapeutic strategies.

Immunosuppressant and immunomodulatory treatments for multifocal motor neuropathy

BACKGROUND

Multifocal motor neuropathy (MMN) is characterised by progressive, predominantly distal, asymmetrical limb weakness and usually multiple partial motor nerve conduction blocks. Intravenous immunoglobulin (IVIg) is beneficial but the role of immunosuppressive agents is uncertain. This is an update of a review first published in 2002 and previously updated in 2003, 2005, 2008 and 2011.

OBJECTIVES

To assess the effects of immunosuppressive agents for the treatment of multifocal motor neuropathy.

SEARCH METHODS

On 22 September 2014 we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE, EMBASE and LILACS for trials of MMN. We also searched two trials registers for ongoing studies.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs) and quasi-RCTs. We considered prospective and retrospective case series and case reports in the Discussion.

DATA COLLECTION AND ANALYSIS

Two review authors searched the titles and abstracts of the articles identified and extracted the data independently.

MAIN RESULTS

Only one RCT of an immunosuppressive or immunomodulatory agent has been performed in MMN. This study randomised 28 participants and showed that mycophenolate mofetil, when used with IVIg, did not significantly improve strength, function or reduce the need for IVIg. No serious adverse events were observed. The study was deemed at low risk of bias. We summarised the results of retrospective and prospective case series in the discussion.

AUTHORS' CONCLUSIONS

According to moderate quality evidence, mycophenolate mofetil did not produce significant benefit in terms of reducing need for IVIg or improving muscle strength in MMN. Trials of other immunosuppressants should be undertaken.

Is dosing of therapeutic immunoglobulins optimal? A review of a three-decade long debate in europe

The consumption of immunoglobulins (Ig) is increasing due to better recognition of antibody deficiencies, an aging population, and new indications. This review aims to examine the various dosing regimens and research developments in the established and in some of the relevant off-label indications in Europe. The background to the current regulatory settings in Europe is provided as a backdrop for the latest developments in primary and secondary immunodeficiencies and in immunomodulatory indications. In these heterogeneous areas, clinical trials encompassing different routes of administration, varying intervals, and infusion rates are paving the way toward more individualized therapy regimens. In primary antibody deficiencies, adjustments in dosing and intervals will depend on the clinical presentation, effective IgG trough levels and IgG metabolism. Ideally, individual pharmacokinetic profiles in conjunction with the clinical phenotype could lead to highly tailored treatment. In practice, incremental dosage increases are necessary to titrate the optimal dose for more severely ill patients. Higher intravenous doses in these patients also have beneficial immunomodulatory effects beyond mere IgG replacement. Better understanding of the pharmacokinetics of Ig therapy is leading to a move away from simplistic "per kg" dosing. Defective antibody production is common in many secondary immunodeficiencies irrespective of whether the causative factor was lymphoid malignancies (established indications), certain autoimmune disorders, immunosuppressive agents, or biologics. This antibody failure, as shown by test immunization, may be amenable to treatment with replacement Ig therapy. In certain immunomodulatory settings [e.g., idiopathic thrombocytopenic purpura (ITP)], selection of patients for Ig therapy may be enhanced by relevant biomarkers in order to exclude non-responders and thus obtain higher response rates. In this review, the developments in dosing of therapeutic immunoglobulins have been limited to high and some medium priority indications such as ITP, Kawasaki' disease, Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, myasthenia gravis, multifocal motor neuropathy, fetal alloimmune thrombocytopenia, fetal hemolytic anemia, and dermatological diseases.

7th International Immunoglobulin Conference: Neurology

Immunoglobulin (Ig) therapy has been used and studied as a treatment for a variety of neurological conditions for decades. In some of these disorders Ig therapy has a significant role as a first-line treatment. This session explores the use of Ig therapy in immune-mediated peripheral neuropathies and various central nervous system (CNS) diseases. Informative practice points relating to the management and treatment of these diseases are discussed. Potential future neurological indications for Ig therapy, as well as data on efficacy and possible mechanisms of action, are also presented. In peripheral immune-mediated neuropathies, data show good response rates to Ig therapy and it is often used as a first-line treatment. Intravenous immunoglobulin (IVIg) and subcutaneous immunoglobulin (SCIg) are both well tolerated, but dose and dosing frequency should be based on individual clinical responses. In Alzheimer's disease, although clinical data show no significant differences between IVIg and placebo, biomarker studies indicate that plasma-derived antibodies may be involved in clearance of amyloid aggregates from the brain. Data suggest that the use of high IVIg doses in early-stage Alzheimer's treatment may warrant further investigation. Ig therapy is considered a valuable option for autoimmune encephalitis, an antibody-mediated CNS disease. Combination treatment with IVIg and corticosteroids shows promising results and is proposed as a first-line treatment in these disorders. Until recently, very little was understood about the pathogenesis of chronic pain disorders. Data now indicate that perpetuation of the pain response may be underpinned by central immune activation. Some data suggest that Ig therapy may mitigate this effect, with good response rates in a number of studies, but these data need confirmation.

Diagnosis and treatment of chronic acquired demyelinating polyneuropathies

Chronic neuropathies are operationally classified as primarily demyelinating or axonal, on the basis of electrodiagnostic or pathological criteria. Demyelinating neuropathies are further classified as hereditary or acquired-this distinction is important, because the acquired neuropathies are immune-mediated and, thus, amenable to treatment. The acquired chronic demyelinating neuropathies include chronic inflammatory demyelinating polyneuropathy (CIDP), neuropathy associated with monoclonal IgM antibodies to myelin-associated glycoprotein (MAG; anti-MAG neuropathy), multifocal motor neuropathy (MMN), and POEMS syndrome. They have characteristic--though overlapping--clinical presentations, are mediated by distinct immune mechanisms, and respond to different therapies. CIDP is the default diagnosis if the neuropathy is demyelinating and no other cause is found. Anti-MAG neuropathy is diagnosed on the basis of the presence of anti-MAG antibodies, MMN is characterized by multifocal weakness and motor conduction blocks, and POEMS syndrome is associated with IgG or IgA λ-type monoclonal gammopathy and osteosclerotic myeloma. The correct diagnosis, however, can be difficult to make in patients with atypical or overlapping presentations, or nondefinitive laboratory studies. First-line treatments include intravenous immunoglobulin (IVIg), corticosteroids or plasmapheresis for CIDP; IVIg for MMN; rituximab for anti-MAG neuropathy; and irradiation or chemotherapy for POEMS syndrome. A correct diagnosis is required for choosing the appropriate treatment, with the aim of preventing progressive neuropathy.

MMN: from immunological cross-talk to conduction block

Multifocal motor neuropathy (MMN) is a rare inflammatory neuropathy characterized by progressive, asymmetric distal limb weakness and conduction block (CB). Clinically MMN is a pure motor neuropathy, which as such can mimic motor neuron disease. GM1-specific IgM antibodies are present in the serum of approximately half of all MMN patients, and are thought to play a key role in the immune pathophysiology. Intravenous immunoglobulin (IVIg) treatment has been shown to be effective in MMN in five randomized placebo-controlled trials. Despite long-term treatment with intravenous immunoglobulin (IVIg), which is efficient in the majority of patients, slowly progressive axonal degeneration and subsequent muscle weakness cannot be fully prevented. In this review, we will discuss the current understanding of the immune pathogenesis underlying MMN and how this may cause CB, available treatment strategies and future therapeutic targets.

Multifocal motor neuropathy: current therapies and novel strategies

Multifocal motor neuropathy (MMN) is a purely motor mononeuritis multiplex characterized by the presence of conduction block on motor but not on sensory nerves and by the presence of high titers of anti-GM1 antibodies. Several data point to a pathogenetic role of the immune system in this neuropathy, although this has not yet been proved. Several uncontrolled studies and randomized controlled trials have demonstrated the efficacy of therapy with high-dose intravenous immunoglobulin (IVIg) in MMN. However, this therapy has a short-lasting effect that needs to be maintained with periodic infusions. This can be partly overcome by the use of subcutaneous immunoglobulin (SCIg) at the same dose. The high cost and need for repeated infusions have led to the search for other immune therapies, the efficacy of which have not yet been confirmed in randomized trials. In addition, some therapies, including corticosteroids and plasma exchange, are not only ineffective but have been associated with clinical worsening. More recently, a number of novel therapies have been investigated in MMN, including interferon-β1a, the anti-CD20 monoclonal antibody rituximab and the complement inhibitor eculizumab. Preliminary data from open-label uncontrolled studies show that some patients improve after these therapies; however, randomized controlled trials are needed to confirm efficacy. Until then, IVIg (and SCIg) remains the mainstay of treatment in MMN, and the use of other immune therapies should only be considered for patients not responding to, or becoming resistant to, IVIg.

Predicting treatment response in chronic, acquired demyelinating neuropathies

Chronic inflammatory demyelinating polyradiculopathy is an immune-mediated neuropathy that was first described approximately 30 years ago. Since that time an increasingly wide spectrum of chronic acquired demyelinating polyneuropathies exhibiting different phenotypes, clinical course and treatment responses to immunomodulatory treatment have been described. Several new therapeutic agents have been prescribed for such conditions, some with promising results. This review summarizes what is presently known about the clinical courses, treatment responses and predictors of response of the chronic inflammatory demyelinating polyradiculopathy subgroups.

Neurology of pregnancy

Pregnancy creates alterations in maternal physiology which predispose to unique neurologic disorders. Pre-eclampsia, eclampsia, certain types of ischemic and hemorrhagic stroke, reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome, and thunderclap headache all appear to share a common origin from vascular endothelial dysfunction, with overlapping clinical presentations. Multiple sclerosis often improves during pregnancy. Compression mononeuropathies may occur in the extremities. Myasthenia gravis may affect second stage labor. Various inflammatory peripheral neuropathies, dystrophies, myopathies may occur during pregnancy. The safety of specific immune suppressants is reviewed. Epilepsy does not have a significant effect upon the course of pregnancy, albeit there is a modest increase in the need for cesarean section. Certain antiepileptic drugs may produce fetal malformations, most notably valproic acid. Brain tumors are rare during pregnancy, but may increase in size due to activation of hormonal receptors on tumor cells surfaces, water retention, and engorged blood vessels.

Lightning can strike twice: an unlucky patient of neurological interest

Poliomyelitis, once a worldwide epidemic, is becoming increasingly rare owing to the introduction of the polio vaccine in the 1950s. It is estimated that the number of cases of polio has reduced by 99% since the Global Polio Eradication Initiative (GPEI) started in 1988. Amyotrophic lateral sclerosis (ALS) is another relatively uncommon condition which also affects anterior horn cells with debilitating neurological, and deadly, consequences. An unusual case of an aggressive form of ALS developing in a 72-year-old patient with paralytic poliomyelitis in childhood is presented. Her initial presentation was puzzling, and our approach to the diagnostic dilemma is discussed.

Multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a rare disorder in which the symptoms are caused by persistent conduction block lesions. The mononeuropathy multiplex progresses over time with increasing axonal loss. The cause of the conduction blocks and axonal loss are not completely understood but immune mechanisms are involved and response to intravenous immunoglobulin has been established. The importance of MMN goes beyond its clinical incidence as the increasing understanding of the pathogenesis of this disorder has implications for other peripheral nerve diseases and for our knowledge of peripheral nerve biology.

Clinical applications of immunoglobulin: update

Human immunoglobulin is the most used blood product in the clinical practice. Immunoglobulin applications have increased quickly since the elucidation of its immunomodulatory and antiinflammatory properties which turned this blood product into a precious tool in the treatment of numerous diseases that present with humoral immune deficiency or that cause immune system dysfunction. Currently, the approved indications for Ig are: primary immunodeficiencies, secondary immunodeficiencies (multiple myeloma or chronic lymphoid leukemia), Kawasaki syndrome, immune thrombocytopenic purpura, Guillain Barré syndrome, graft-versus-host disease following bone marrow transplantation and repeat infections in HIV children. On the other hand, there are numerous "off-label" indications of immunoglobulin, which represent 20-60% of all clinical applications of this drug. It is important to study all these indications and, above all, the scientific evidence for its use, in order to provide patients with a new therapeutic option without burdening the health system. This review results from a wide selection of papers identified in the Pubmed and Lilacs scientific electronic databases. A group of descriptors were used from human immunoglobulin to the names of each disease that immunoglobulin is clinically applied. Our main objective is to list the numerous indications of immunoglobulin, both authorized and "off-label" and to analyze these indications in the light of the most recent scientific evidence.

A comparison between intravenous and subcutmaneous immunogobulin

Multifocal motor neuropathy (MMN) is a rare immune-mediated disease that presents with predominantly distal motor weakness in one or more limbs without sensory loss. Symptoms may give riseto functional impairment and consequently may affect quality of life. High-dose intravenous immunoglobulin's therapy (IVIg) is the current mainstay treatment, however, subcutaneous immunoglobuli(SCIg) is emerging as a viable alternative. The purpose of this study was to explore the patients' experience of SCIg and ascertain if those receiving it had an improved quality of life and treatmentsatisfaction compared to those receiving IVIg. Using a mixed method approach this paper will present its findings and key implications for clinical and research practice are considered. The results from this study suggest that home SCIg therapy may prove a more desirable treatment option than IVIg for a proportion of MMN patients.

Immunosuppressant and immunomodulatory treatments for multifocal motor neuropathy

BACKGROUND

Multifocal motor neuropathy is characterised by progressive, predominantly distal, asymmetrical limb weakness and usually multiple partial motor nerve conduction blocks. Intravenous immunoglobulin is beneficial but the role of immunosuppressive agents is uncertain. This is an update of a review first published in 2002 and previously updated in 2003, 2005 and 2008.

OBJECTIVES

To provide the best available evidence from randomised controlled trials on the role of immunosuppressive agents for the treatment of multifocal motor neuropathy.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (4 October 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (2011, Issue 3 in The Cochrane Library), MEDLINE (January 1966 to September 2011), EMBASE (January 1980 to September 2011), and LILACS (January 1982 to September 2011) for trials of multifocal motor neuropathy.

SELECTION CRITERIA

We planned to include randomised and quasi-randomised controlled trials. We considered prospective and retrospective case series and case reports in the Discussion.

DATA COLLECTION AND ANALYSIS

Two review authors searched the titles and abstracts of the articles identified and extracted the data independently.

MAIN RESULTS

Only one randomised controlled trial of an immunosuppressive or immunomodulatory agent has been performed in multifocal motor neuropathy. This study randomised 28 participants and showed that mycophenolate mofetil, when used with intravenous immunoglobulin, did not significantly improve strength, function or reduce the need for intravenous immunoglobulin. No serious adverse events were observed. The study was deemed at low risk of bias. We summarised the results of retrospective and prospective case series in the discussion.

AUTHORS' CONCLUSIONS

According to moderate quality evidence, mycophenolate mofetil did not produce significant benefit in terms of reducing need for intravenous immunoglobulin or improving muscle strength. Trials of other immunosuppressants should be undertaken.

New Frontiers in Subcutaneous Immunoglobulin Treatment

Subcutaneous immunoglobulin (SCIG) treatment provides stable serum immunoglobulin G (IgG) levels, is associated with fewer systemic adverse events than intravenous immunoglobulin (IVIG) treatment, and offers the convenience of home therapy. In clinical practice, IVIG is still used preferentially for initiation of treatment in newly diagnosed patients with primary immunodeficiency (PI) and for immunomodulatory therapy, such as treatment of peripheral neuropathies, when high doses are believed to be necessary. The authors discuss recent experience in using SCIG in place of IVIG in these settings. SCIG has been successfully used for initiation of therapy in previously untreated PI patients. Seventeen of 18 PI patients achieved serum IgG levels ≥5 g/L after the loading phase. Daily treatment was well tolerated and provided opportunities for patient/parent training in self-infusion. SCIG has been used for maintenance therapy in multifocal motor neuropathy (MMN) in three recent clinical trials, with good efficacy and tolerability results. Seven of eight MMN patients maintained serum IgG levels of 14–22 g/L with a mean dose of 272 mg/kg/week, had stable muscle strength, and felt comfortable with self-administration. Four patients with polymyositis or dermatomyositis achieved improvement in serum creatine kinase levels and muscle strength with SCIG therapy. Recent experience with SCIG suggests that traditional concepts of immunoglobulin therapy may be challenged to increase available therapy options. SCIG can be used to achieve high IgG levels within several days in untreated PI patients and to maintain high serum levels, as shown in patients with MMN.

Do A-waves help predict intravenous immunoglobulin response in multifocal motor neuropathy without block?

INTRODUCTION

Are there electrophysiological findings that predict response to intravenous immunoglobulin (IVIg) in patients with lower motor neuron (LMN) syndromes without multifocal conduction block (MCB)?

METHODS

We enrolled 9 patients with LMN syndromes without MCB to receive 18 weeks of IVIg therapy. Response was measured at weeks 2 and 18 using the Appel Amyotrophic Lateral Sclerosis (AALS) score (includes grip and pincer strength measures), ALS Functional Rating Scale (ALSFRS), and electrophysiological measures, including motor unit estimates (MUNEs).

RESULTS

No change occurred in AALS or ALSFRS scores posttreatment. Grip/pincer strength increased in 7 patients (P = 0.028) after initial treatment (responders); 2 showed no improvement (non-responders). No electrophysiological measure changed after treatment in either group but MUNEs trended higher (P = 0.055). "Abnormal A-waves" (complex, repetitive biphasic, or present in multiple nerves) occurred in pretreatment studies more often in responders (P = 0.028).

DISCUSSION

"Abnormal A-waves" may signal IVIg-responsive LMN syndromes even if conduction block is absent.

Immunomodulatory therapy to achieve maximum efficacy: doses, monitoring, compliance, and self-infusion at home

INTRODUCTION

The Oxford Programme for Immunomodulatory Immunoglobulin Therapy has been operating since 1992 at Oxford Radcliffe Hospitals in the UK. Initially, this program was set up for patients with multifocal motor neuropathy or chronic inflammatory demyelinating poly-neuropathy to receive reduced doses of intravenous immunoglobulin (IVIG) in clinic on a regular basis (usually every 3 weeks). The program then rapidly expanded to include self-infusion at home, which monitoring showed to be safe and effective. It has been since extended to the treatment of other autoimmune diseases in which IVIG has been shown to be efficacious.

METHODS

This review includes details of the program such as the training of patients, dosing with immunoglobulin, and monitoring and compliance for self-infusion at home, with cases to illustrate these points.

RESULTS

In addition, the Evidence for efficacy and the effects of confounding morbidities will be are included described. More recently, subcutaneous immunoglobulin therapy (SCIG) has been used in several chronic autoimmune peripheral neuropathies and in epidermolysis bullosa acquisita, with equally good effect. Trials of SCIG in other autoimmune diseases are planned.

[Intravenous IgG for treatment of neuromuscular diseases]

BACKGROUND

Highly purified IgG administered intravenously (IVIG) is used to treat many neurological diseases.

MATERIAL AND METHODS

This review is based on articles identified through a search in PubMed and the authors' knowledge and experience within the field.

RESULTS

The effect of IVIG has been best documented in the treatment of acute and chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy and acute exacerbation of myasthenia gravis. Some smaller studies support explorative IVIG treatment in other neurological diseases such as Lambert-Eaton myasthenic syndrome, paraproteinemic neuropathy, neuropathy caused by vasculitis, inflammatory myopathies and stiff-person syndrome.

INTERPRETATION

IVIG affects the immune system in different ways. Documentation for the effect of such treatment in most neurological diseases remains sparse.

[Monthly low-dose immunoglobulin infusion as a maintenance therapy for multifocal motor neuropathy may reduce allergic adverse effects: a case report]

A 41-year-old man with multiple motor neuropathy developed weakness of the left hand at the age of 35 years. The weakness gradually progressed to his right hand. High-dose intravenous immunoglobulin (IVIg) therapy (0.4 g/kg for 5 consecutive days) improved the muscle weakness in the hands but led to the development of generalized severe pompholyx that spread to the skin over the entire body. Because muscle weakness of the hands worsened several months after IVIg therapy, we attempted another course of IVIg therapy. However, antiallergic agents and oral corticosteroids did not suppress the pompholyx induced by the high-dose IVIg. Hence, the treatment was switched to low-dose immunoglobulin therapy (0.4 g/kg for one day) once every month. After more than 8 months of low-dose therapy, only mild form of pompholyx remained and the muscle strength was maintained without further deterioration.

Intravenous immunoglobulin for the treatment of chronic inflammatory demyelinating polyradiculoneuropathy: a systematic review and meta-analysis

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired immune-mediated inflammatory disorder that targets the myelin sheaths of the peripheral nervous system. Intravenous immunoglobulin (IVIg) is a blood product containing immunoglobulin G pooled from many human donors. In fall 2008, CIDP became an approved indication for IVIg in the United States and Canada.

OBJECTIVE

To evaluate the clinical effectiveness and safety of IVIg for the treatment of CIDP through a systematic review of published randomized controlled trials.

METHODS

We searched the MEDLINE (1996-2009, including in-process and other non-indexed citations), Embase (1996-2009) and other databases through the Ovid interface. We applied a methodological filter to limit retrieval to controlled clinical trials, meta-analyses and systematic reviews, and health technology assessments. Retrieval was limited to studies involving humans, and no language restrictions were employed. We pooled extracted data to estimate the effect size of IVIg treatment based on the random-effects model.

RESULTS

We identified 9 unique randomized controlled trials. Of these, 3 compared IVIg therapy with an active comparator (plasma exchange, plasma exchange using extracorporeal immunoadsorption, oral prednisolone, respectively); the other 6 trials had placebo controls. No incremental benefit was seen in terms of primary outcomes for comparisons of IVIg therapy and an active comparator. Data from 4 of the 6 placebo-controlled trials were included in a meta-analysis. A significant improvement in disability (i.e., reduction in disability score) was found, with a standardized mean difference of 0.65 (95% confidence interval [CI] 0.23 to 1.08) in favour of IVIg. A pooled analysis of the proportion of patients with a response to treatment, as defined by the investigators of each of the trials, resulted in a risk ratio of 2.74 (95% CI 1.80 to 4.15) favouring IVIg.

INTERPRETATION

IVIg therapy was statistically superior to placebo in reducing disability and impairment among patients with CIDP. The effectiveness of IVIg was similar to that of the alternative treatment strategies of plasma exchange and oral prednisolone.