Treatment of chronic inflammatory demyelinating polyneuropathy: from molecular bases to practical considerations

[Modern aspects of diagnosis and treatment of chronic inflammatory demyelinating polyneuropathy in children]

OBJECTIVE

Analysis of demographic, clinical, laboratory, electrophysiological and neuroimaging data and pathogenetic therapy of pediatric patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

MATERIAL AND METHODS

Patients (n=30) were observed in a separate structural unit of the Russian Children's Clinical Hospital of the Russian National Research Medical University named after. N.I. Pirogova Ministry of Health of the Russian Federation in the period from 2006 to 2023. The examination was carried out in accordance with the recommendations of the Joint Task Force of the European Federation of Neurological Societies and the Peripheral Nerve Society on the Management of CIDP (2021). All patients received immunotherapy, including intravenous immunoglobulin (IVIG) (n=1), IVIG and glucocorticosteroids (GCS) (n=17, 56.7%), IVIG+GCS+plasmapheresis (n=12, 40.0%). Alternative therapy included cyclophosphamide (n=1), cyclophosphamide followed by mycophenolate mofetil (n=1), rituximab (n=2, 6.6%), azathioprine (n=3), mycophenolate mofetil (n=2, 6.6%).

RESULTS

In all patients, there was a significant difference between scores on the MRCss and INCAT functional scales before and after treatment. At the moment, 11/30 (36.6%) patients are in clinical remission and are not receiving pathogenetic therapy. The median duration of remission is 48 months (30-84). The longest remission (84 months) was observed in a patient with the onset of CIDP at the age of 1 year 7 months.

CONCLUSION

Early diagnosis of CIDP is important, since the disease is potentially curable; early administration of pathogenetic therapy provides a long-term favorable prognosis.

Intravenous immunoglobulin preparations attenuate lysolecithin-induced peripheral demyelination in mice and comprise anti-large myelin protein zero antibody

Intravenous immunoglobulin (IVIg) has been used to treat inflammatory demyelinating diseases such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barré syndrome, and multifocal motor neuropathy. Despite studies demonstrating the clinical effectiveness of IVIg, the mechanisms underlying its effects remain to be elucidated in detail. Herein, we examined the effects of IVIg on lysolecithin-induced demyelination of the sciatic nerve in a mouse model. Mice -administered with IVIg 1 and 3 days post-injection (dpi) of lysolecithin -exhibited a significantly decreased demyelination area at 7 dpi. Immunoblotting analysis using two different preparations revealed that IVIg reacted with a 36-kDa membrane glycoprotein in the sciatic nerve. Subsequent analyses of peptide absorption identified the protein as a myelin protein in the peripheral nervous system (PNS) known as large myelin protein zero (L-MPZ). Moreover, injected IVIg penetrated the demyelinating lesion, leading to deposition on L-MPZ in the myelin debris. These results indicate that IVIg may modulate PNS demyelination, possibly by binding to L-MPZ on myelin debris.

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

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

Individualizing Therapy in CIDP: A Mini-Review Comparing the Pharmacokinetics of Ig With SCIg and IVIg

Immunoglobulin (Ig) therapy is a first-line treatment for CIDP, which can be administered intravenously (IVIg) or subcutaneously (SCIg) and is often required long term. The differences between these modes of administration and how they can affect dosing strategies and treatment optimization need to be understood. In general, the efficacy of IVIg and SCIg appear comparable in CIDP, but SCIg may offer some safety and quality of life advantages to some patients. The differences in pharmacokinetic (PK) profile and infusion regimens account for many of the differences between IVIg and SCIg. IVIg is administered as a large bolus every 3–4 weeks resulting in cyclic fluctuations in Ig concentration that have been linked to systemic adverse events (AEs) (potentially caused by high Ig levels) and end of dose “wear-off” effects (potentially caused by low Ig concentration). SCIg is administered as a smaller weekly, or twice weekly, volume resulting in near steady-state Ig levels that have been linked to continuously maintained function and reduced systemic AEs, but an increase in local reactions at the infusion site. The reduced frequency of systemic AEs observed with SCIg is likely related to the avoidance of high Ig concentrations. Some small studies in immune-mediated neuropathies have focused on serum Ig data to evaluate its potential use as a biomarker to aid clinical decision-making. Analyzing dose data may help understand how establishing and monitoring patients' Ig concentration could aid dose optimization and the transition from IVIg to SCIg therapy.

Systematic literature review of burden of illness in chronic inflammatory demyelinating polyneuropathy (CIDP)

Background

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare neurological disorder characterised by muscle weakness and impaired sensory function. The present study provides a comprehensive literature review of the burden of illness of CIDP.

Methods

Systematic literature search of PubMed, Embase, and key conferences in May 2019. Search terms identified studies on the epidemiology, humanistic burden, current treatment, and economic burden of CIDP published since 2009 in English.

Results

Forty-five full texts and nineteen conference proceedings were identified on the epidemiology (n = 9), humanistic burden (n = 7), current treatment (n = 40), and economic burden (n = 8) of CIDP. Epidemiological studies showed incidence and prevalence of 0.2–1.6 and 0.8–8.9 per 100,000, respectively, depending on geography and diagnostic criteria. Humanistic burden studies revealed that patients experienced physical and psychosocial burden, including impaired physical function, pain and depression. Publications on current treatments reported on six main types of therapy: intravenous immunoglobulins, subcutaneous immunoglobulins, corticosteroids, plasma exchange, immunosuppressants, and immunomodulators. Treatments may be burdensome, due to adverse events and reduced independence caused by treatment administration setting. In Germany, UK, France, and the US, CIDP economic burden was driven by direct costs of treatment and hospitalisation. CIDP was associated with indirect costs driven by impaired productivity.

Conclusions

This first systematic review of CIDP burden of illness demonstrates the high physical and psychosocial burden of this rare disease. Future research is required to fully characterise the burden of CIDP, and to understand how appropriate treatment can mitigate burden for patients and healthcare systems.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-09998-8) contains supplementary material, which is available to authorized users.

Treatment Patterns and Costs of Chronic Inflammatory Demyelinating Polyneuropathy: A Claims Database Analysis

BACKGROUND

Corticosteroids, plasma exchange, and intravenous immunoglobulin (IVIG) have been standard-of-care treatments for chronic inflammatory demyelinating polyneuropathy (CIDP) for more than 2 decades. Despite guideline recommendations for best clinical practices, heterogeneity in patient presentation and the course of treatment for CIDP remains. There is limited literature regarding the real-world treatment patterns of and costs associated with CIDP.

OBJECTIVE

To analyze and describe the real-world treatment patterns of and economic burden associated with CIDP.

METHODS

This retrospective cohort study evaluated the treatment patterns and CIDP-related healthcare costs over a 2-year follow-up period for patients with newly diagnosed CIDP who had commercial insurance, using claims data from the IMS LifeLink PharMetrics Plus Claims database between 2009 through 2014. Treatment-naïve patients with newly diagnosed CIDP were evaluated for 2 years postdiagnosis, which captured the treatments used and the resource utilization. The patients were defined as receiving active CIDP therapy (ie, IVIG, immunosuppressants, oral or intravenous steroids, or plasma exchange) or active surveillance.

RESULTS

Of the 525 patients identified with newly diagnosed CIDP, 55.2% of patients were prescribed only steroid therapy, and 25.3% of patients were prescribed an IVIG therapy during the 2-year follow-up. The median time to the initial treatment was shortest for patients receiving plasma exchange alone (0.03 months) or in combination with a steroid (0.03 months), followed by IVIG plus another therapy (0.53 months), and then IVIG alone (0.71 months). Initiating therapy with steroids alone took the longest mean time (6.51 months) to start the treatment. The median length of time to receive therapy was longest for the steroid plus plasma exchange cohort (21.8 months), followed by the steroid plus immunosuppressant cohort (10.1 months), and the 2 IVIG cohorts (9.04 months for IVIG alone and 9.82 months for IVIG plus another therapy). The mean total CIDP-specific 2-year follow-up costs were highest for the cohort that received IVIG alone ($119,928) or with an additional therapy ($133,334) and lowest for patients who received active surveillance ($3723) or steroids alone ($3101).

CONCLUSIONS

Steroid therapy was initiated later and resulted in a shorter duration of treatment than other treatment options for patients with CIDP, which may reflect diagnostic uncertainty, disease severity or remission, therapeutic challenge to determine diagnosis, or the side-effect profile of steroids. The use of steroids alone was the most common prescribed treatment for CIDP. Further research is needed to understand the rationale for treatment decisions in this patient population and their potential impact on patients and health plans.

FTY720 controls disease severity and attenuates sciatic nerve damage in chronic experimental autoimmune neuritis

Background

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune-mediated inflammatory disease of the peripheral nervous system characterized by a response directed against certain myelin proteins and for which therapies are limited. Previous studies have suggested a beneficial role of FTY720, a sphingosine 1-phosphate (S1P) receptor agonist, known to deplete lymphocytes from the peripheral blood by sequestering them into lymph nodes, in the treatment of experimental autoimmune neuritis (EAN). Therefore, we investigated whether FTY720 is also beneficial in chronic experimental autoimmune neuritis (c-EAN), a recently developed rat model mimicking human CIDP.

Methods

c-EAN was induced in Lewis rats by immunization with S-palm P0(180–199) peptide. Rats were treated with FTY720 (1 mg/kg) or vehicle intraperitoneally once daily from the onset of clinical signs for 18 days; clinical signs were assessed daily until 60 days post-immunization (dpi). Electrophysiological and histological features were examined at different time points. We also evaluated the serum levels of different pro- and anti-inflammatory cytokines by ELISA or flow cytometry at 18, 40, and 60 dpi.

Results

Our data demonstrate that FTY720 decreased the severity and abolished the chronicity of the disease in c-EAN rats. Therapeutic FTY720 treatment reversed electrophysiological and histological anomalies, suggesting that myelinated fibers were subsequently preserved, it inhibited macrophage and IL-17⁺ cell infiltration in PNS, and it significantly reduced circulating pro-inflammatory cytokines.

Conclusions

FTY720 treatment has beneficial effects on c-EAN, a new animal model mimicking human CIDP. We have shown that FTY720 is an effective immunomodulatory agent, improving the disease course of c-EAN, preserving the myelinated fibers, attenuating the axonal degeneration, and decreasing the number of infiltrated inflammatory cells in peripheral nerves. These data confirm the interest of testing FTY720 or molecules targeting S1P in human peripheral neuropathies.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1441-4) contains supplementary material, which is available to authorized users.

Enhanced Immune Response in Immunodeficient Mice Improves Peripheral Nerve Regeneration Following Axotomy

Injuries to peripheral nerves cause loss of motor and sensory function, greatly affecting life quality. Successful repair of the lesioned nerve requires efficient cell debris removal, followed by axon regeneration and reinnervation of target organs. Such process is orchestrated by several cellular and molecular events in which glial and immune cells actively participate. It is known that tissue clearance is largely improved by macrophages, which activation is potentiated by cells and molecules of the acquired immune system, such as T helper lymphocytes and antibodies, respectively. In the present work, we evaluated the contribution of lymphocytes in the regenerative process of crushed sciatic nerves of immunocompetent (wild-type, WT) and T and B-deficient (RAG-KO) mice. In Knockout animals, we found increased amount of macrophages under basal conditions and during the initial phase of the regenerative process, that was evaluated at 2, 4, and 8 weeks after lesion (wal). That parallels with faster axonal regeneration evidenced by the quantification of neurofilament and a growth associated protein immunolabeling. The motor function, evaluated by the sciatic function index, was fully recovered in both mouse strains within 4 wal, either in a progressive fashion, as observed for RAG-KO mice, or presenting a subtle regression, as seen in WT mice between 2 and 3 wal. Interestingly, boosting the immune response by early adoptive transference of activated WT lymphocytes at 3 days after lesion improved motor recovery in WT and RAG-KO mice, which was not ameliorated when cells were transferred at 2 wal. When monitoring lymphocytes by in vivo imaging, in both mouse strains, cells migrated to the lesion site shortly after transference, remaining in the injured limb up to its complete motor recovery. Moreover, a first peak of hyperalgesia, determined by von-Frey test, was coincident with increased lymphocyte infiltration in the damaged paw. Overall, the present results suggest that a wave of immune cell infiltration takes place during subacute phase of axonal regeneration, resulting in transient set back of motor recovery following peripheral axonal injury. Moreover, modulation of the immune response can be an efficient approach to speed up nerve regeneration.

CIDP variants in diabetes: measuring treatment response with a small nerve fiber test

INTRODUCTION

Chronic inflammatory demyelinating polyneuropathy (CIDP) is eleven times more common among people with diabetes than the general population and is treatable with appropriate immunotherapy. Treatment response is usually measured clinically (symptomatic and functional improvement). We present a case of a patient with type 2 diabetes (T2D) and CIDP whose treatment response was measurable with the Sudoscan sudomotor function test. This test may represent a new objective evaluation of the treatment of CIDP.

CASE DESCRIPTION

The patient is a 60year old male initially referred to our center in August 2012, at which time he was diagnosed with CIDP based on AAN electrodiagnostic criteria (NCS). Autonomic functions were significant for low heart rate variability response to expiration/inspiration (E/I), Valsalva maneuver and the ratio of the RR interval for the 30th to the 15th beat upon standing (1.08, 1.12, 1.05 respectively), and frequency analysis of the total spectral power, the standard deviation of the normal RR intervals (sdNN) and their root mean squared (rmsSD). Sudoscan electrochemical skin conductances (ESC), measuring small nerve fiber function on the palms and soles, were very low: 23 μS in the feet and 32 μS in the hands. After one cycle of intravenous immunoglobulin (IVIG: 6 doses total, 75g each) the patient had no change in symptoms of burning, numbness, shooting pains, and gait impairment. However, E/I, Valsalva, and 30:15 ratios (1.19, 1.36, 1.39 respectively) were improved, as were NCS. Sudoscan scores for feet and hands were unchanged (23 μS and 32 μS). In March 2013, the patient's autonomic functions worsened (E/I, Valsalva, and 30:15 ratios 1.1, 1.07, 1.12 respectively), but feet and hand ESC started to show improvement (35 μS and 52 μS respectively). Azathioprine was started. Eight days after a second cycle of IVIG in January 2014, the patient reported for the first time less burning, shooting pains and tingling. E/I, Valsalva, and 30:15 ratios remained low (1.03, 1.07, and not analyzable, respectively), while foot and hand ESC scores continued to improve (43 μS and 55 μS respectively).

DISCUSSION

CIDP diagnosis and treatment response are difficult in the diabetic patient. We found that NCS and autonomic function tests did not correlate well with clinical status while numerical Sudoscan scores matched closely symptomatic changes. ESC have been found to correlate well with peripheral small fiber function and neuropathic symptoms in DPN. The findings in this patient warrant further investigation of the use of Sudoscan to monitor CIDP response to therapy.

Variations of the perforin gene in patients with chronic inflammatory demyelinating polyradiculoneuropathy

Perforin (PRF) has a key role in the function of cytotoxic T and natural killer cells. Rare variations of PRF1 predispose to autoimmunity. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system, involving defective lymphocyte apoptosis. The aim of this study was to investigate the role of PRF1 in CIDP. The entire coding region of PRF1 was sequenced in 94 patients and 158 controls. We found three missense variations leading to amino acid substitutions and one nonsense variation resulting in a premature stop codon. All variations would decrease PRF activity. Their overall frequency was significantly higher in patients than in controls (odds ratio (OR)=4.47). The most frequent variation was p.Ala91Val (OR=3.92) previously associated with other autoimmune diseases. Clinical analysis showed that PRF1 variations were more frequent in relapsing patients and in patients displaying axonal damage. These data suggest that PRF1 variations may influence CIDP development and course.