Pathogenesis and treatment of immune-mediated neuropathies

Management of Severe Pain in a Case of Sensory Guillain-Barre Syndrome

Guillain-Barre syndrome (GBS) is an acute post-infectious polyradiculoneuropathy characterized by autoantibodies targeting host antigens, resulting in nerve fiber demyelination and axonal degeneration. While symmetric ascending weakness is typical, neuropathic pain is a common yet variable manifestation. We present a case of a 52-year-old man with progressive bilateral leg weakness and severe neuropathic pain following a flu-like illness. Despite conventional analgesics, his pain persisted, necessitating a unique pain management approach. The patient's examination revealed hyporeflexia and sensory deficits consistent with GBS. Diagnostic workup, including lumbar puncture, showed albuminocytologic dissociation. Plasma exchange therapy was initiated, but severe nocturnal neuropathic pain persisted, exacerbating during treatment. Conventional pain medications were ineffective, prompting a multimodal approach. Combining hydromorphone and lorazepam provided significant pain relief, enabling completion of plasmapheresis sessions. This regimen, supplemented with gabapentin, proved effective in managing both GBS-associated and treatment-induced pain. This case underscores the debilitating nature of GBS-related pain and the importance of tailored pain management strategies. While conventional agents may fail, a multimodal approach, including opioids and adjunctive medications, can offer relief, facilitating essential treatments like plasmapheresis. Careful monitoring is imperative to mitigate risks associated with potent analgesics. Our experience contributes to the armamentarium for managing GBS-related pain, emphasizing individualized care to improve patient outcomes.

Molecular mechanism of lncRNAs in pathogenesis and diagnosis of auto-immune diseases, with a special focus on lncRNA-based therapeutic approaches

Autoimmune diseases are a diverse set of conditions defined by organ damage due to abnormal innate and acquired immune system responses. The pathophysiology of autoimmune disorders is exceedingly intricate and has yet to be fully understood. The study of long non-coding RNAs (lncRNAs), non-protein-coding RNAs with at least 200 nucleotides in length, has gained significant attention due to the completion of the human genome project and the advancement of high-throughput genomic approaches. Recent research has demonstrated how lncRNA alters disease development to different degrees. Although lncRNA research has made significant progress in cancer and generative disorders, autoimmune illnesses are a relatively new research area. Moreover, lncRNAs play crucial functions in differentiating various immune cells, and their potential relationships with autoimmune diseases have received growing attention. Because of the importance of Th17/Treg axis in auto-immune disease development, in this review, we discuss various molecular mechanisms by which lncRNAs regulate the differentiation of Th17/Treg cells. Also, we reviewed recent findings regarding the several approaches in the application of lncRNAs in the diagnosis and treatment of human autoimmune diseases, as well as current challenges in lncRNA-based therapeutic approaches to auto-immune diseases.

Kinesin-5 inhibition improves neural regeneration in experimental autoimmune neuritis

BACKGROUND

Autoimmune neuropathies can result in long-term disability and incomplete recovery, despite adequate first-line therapy. Kinesin-5 inhibition was shown to accelerate neurite outgrowth in different preclinical studies. Here, we evaluated the potential neuro-regenerative effects of the small molecule kinesin-5 inhibitor monastrol in a rodent model of acute autoimmune neuropathies, experimental autoimmune neuritis.

METHODS

Experimental autoimmune neuritis was induced in Lewis rats with the neurogenic P2-peptide. At the beginning of the recovery phase at day 18, the animals were treated with 1 mg/kg monastrol or sham and observed until day 30 post-immunisation. Electrophysiological and histological analysis for markers of inflammation and remyelination of the sciatic nerve were performed. Neuromuscular junctions of the tibialis anterior muscles were analysed for reinnervation. We further treated human induced pluripotent stem cells-derived secondary motor neurons with monastrol in different concentrations and performed a neurite outgrowth assay.

RESULTS

Treatment with monastrol enhanced functional and histological recovery in experimental autoimmune neuritis. Motor nerve conduction velocity at day 30 in the treated animals was comparable to pre-neuritis values. Monastrol-treated animals showed partially reinnervated or intact neuromuscular junctions. A significant and dose-dependent accelerated neurite outgrowth was observed after kinesin-5 inhibition as a possible mode of action.

CONCLUSION

Pharmacological kinesin-5 inhibition improves the functional outcome in experimental autoimmune neuritis through accelerated motor neurite outgrowth and histological recovery. This approach could be of interest to improve the outcome of autoimmune neuropathy patients.

Dysregulation of lncRNAs in autoimmune neuropathies

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Guillain-Barré syndrome (GBS) are inflammatory neuropathies with different clinical courses but similar underlying mechanisms. Long non-coding RNAs (lncRNAs) might affect pathogenesis of these conditions. In the current project, we have selected HULC, PVT1, MEG3, SPRY4-IT1, LINC-ROR and DSCAM-AS1 lncRNAs to appraise their transcript levels in the circulation of CIDP and GBS cases versus controls. Expression of HULC was higher in CIDP patients compared with healthy persons (Ratio of mean expression (RME) = 7.62, SE = 0.72, P < 0.001). While expression of this lncRNA was not different between female CIDP cases and female controls, its expression was higher in male CIDP cases compared with male controls (RME = 13.50, SE = 0.98, P < 0.001). Similarly, expression of HULC was higher in total GBS cases compared with healthy persons (RME = 4.57, SE = 0.65, P < 0.001) and in male cases compared with male controls (RME = 5.48, SE = 0.82, P < 0.001). Similar pattern of expression was detected between total cases and total controls. PVT1 was up-regulated in CIDP cases compared with controls (RME = 3.04, SE = 0.51, P < 0.001) and in both male and female CIDP cases compared with sex-matched controls. Similarly, PVT1 was up-regulated in GBS cases compared with controls (RME = 2.99, SE = 0.55, P vale < 0.001) and in total patients compared with total controls (RME = 3.02, SE = 0.43, P < 0.001). Expression levels of DSCAM-AS1 and SPRY4-IT1 were higher in CIDP and GBS cases compared with healthy subjects and in both sexes compared with gender-matched healthy persons. Although LINC-ROR was up-regulated in total CIDP and total GBS cases compared with controls, in sex-based comparisons, it was only up-regulated in male CIDP cases compared with male controls (RME = 3.06, P = 0.03). Finally, expression of MEG3 was up-regulated in all subgroups of patients versus controls except for male GBS controls. SPRY4-IT could differentiate CIDP cases from controls with AUC = 0.84, sensitivity = 0.63 and specificity = 0.97. AUC values of DSCAM-AS1, MEG3, HULC, PVT1 and LINC-ROR were 0.80, 0.75, 0.74, 0.73 and 0.72, respectively. In differentiation between GBS cases and controls, SPRY4-IT and DSCAM-AS1 has the AUC value of 0.8. None of lncRNAs could appropriately differentiate between CIDP and GBS cases. Combination of all lncRNAs could not significantly enhance the diagnostic power. Taken together, these lncRNAs might be involved in the development of CIDP or GBS.

Assessment of Expression of SOCS Genes in Acquired Immune-Mediated Polyneuropathies

Acquired immune-mediated polyneuropathies are classified to some subtypes among them are acute and chronic inflammatory demyelinating polyradiculoneuropathies (AIDP and CIDP). These two conditions share some common signs and underlying mechanisms. Based on the roles of Suppressor of cytokine signaling (SOCS) genes in the modulation of immune system reactions, these genes might be involved in the pathogenesis of these conditions. We evaluated expression of SOCS1-3 and SOCS5 genes in the leukocytes of 32 cases of CIDP, 19 cases of AIDP and 40 age- and sex-matched controls using real time PCR method. The Bayesian regression model was used to estimate differences in mean values of genes expressions between cases and control group. Expression levels of SOCS1 and SOCS2 were significantly lower in male patients compared with controls. This sex-specific pattern was also observed for SOCS3 down-regulation. Based on the area under curve values in Receiver Operating Characteristics (ROC) curve, diagnostic powers of SOCS1, SOCS2, SOCS3 and SOCS5 genes in the mentioned disorder were 0.61, 0.73, 0.68 and 0.58, respectively. Expression of none of genes was correlated with age of enrolled cases. The current study shows evidences for participation of SOCS genes in the pathophysiology of acquired immune-mediated polyneuropathies.

Over-Expression of Immune-Related lncRNAs in Inflammatory Demyelinating Polyradiculoneuropathies

Long non-coding RNAs (lncRNAs) have crucial roles in the pathogenesis of immune-related disorders. However, their role in the pathobiology of inflammatory demyelinating polyradiculoneuropathies remains unclear. In the current study, we measured peripheral expression of four lncRNAs, namely TUG1, FAS-AS1, NEAT1, and GAS5, in patients with acute/chronic inflammatory demyelinating polyradiculoneuropathies (AIDP/CIDP) compared with healthy subjects. Notably, all lncRNAs were over-expressed in patients compared with controls (P < 0.0001 for all lncRNAs). When assessing their expressions in AIDP and CIDP groups separately, TUG1 and NEAT1 were up-regulated in both patient groups compared with controls, yet FAS-AS1 and GAS5 were only up-regulated in CIDP cases. There were remarkable pairwise correlations between expression levels of these lncRNAs in all study groups. Based on the above-mentioned data, we suggest participation of these for lncRNAs in the pathogenesis of inflammatory demyelinating polyradiculoneuropathies. Moreover, FAS-AS1 and GAS5 lncRNAs have type-specific roles in this regard. Future functional studies are needed to elaborate the molecular mechanisms of the contribution of these transcripts in AIDP/CIDP.

Challenges in the development of nanoparticle-based imaging agents: Characterization and biology

Despite imaging agents being some of the earliest nanomedicines in clinical use, the vast majority of current research and translational activities in the nanomedicine field involves therapeutics, while imaging agents are severely underrepresented. The reasons for this lack of representation are several fold, including difficulties in synthesis and scale-up, biocompatibility issues, lack of suitable tissue/disease selective targeting ligands and receptors, and a high bar for regulatory approval. The recent focus on immunotherapies and personalized medicine, and development of nanoparticle constructs with better tissue distribution and selectivity, provide new opportunities for nanomedicine imaging agent development. This manuscript will provide an overview of trends in imaging nanomedicine characterization and biocompatibility, and new horizons for future development. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine.

High Levels of Il-19 in Patients with Chronic Inflammatory Demyelinating Polyneuropathy

Immune-mediated neuropathies include some specific types such as acute and chronic inflammatory demyelinating polyneuropathy (AIDP and CIDP). Previous studies have demonstrated abnormal cellular or humoral immune responses in these conditions. Although aberrant regulation of several cytokines have been reported in AIDP and CIDP, the significance of interleukin 19 (IL-19) in these conditions have not been elucidated yet. In the current study, we assessed serum levels of IL-19 in 12 CIDP patients (female/male ratio, 4/8), 9 AIDP patients (female/male ratio, 3/6), and 27 normal subjects (female/male ratio. 8/19) using commercial ELISA kits. Notably, we detected higher levels of this cytokine in CIDP patients (136.4 ± 8.57 ng/l) compared with both AIDP patients (93.89 ± 2.26 ng/l) and controls (83.78 ± 1.72 ng/l). However, the differences between AIDP patients and controls were not significant. The current study demonstrates the role of IL-19 in the pathogenesis of CIDP and potentiates this cytokine as a biomarker for this condition.

Assessment of IL-38 Levels in Patients with Acquired Immune-Mediated Polyneuropathies

Acute and chronic inflammatory demyelinating polyneuropathy (AIDP and CIDP) are two types of immune-mediated neuropathies in which abnormal cellular or humoral immune responses have been observed. Although dysregulation of several cytokines has been detected in these disorders, expression of interleukin 38 (IL-38) has not yet been assessed in AIDP and CIDP. In the current study, we evaluated serum concentrations of this member of the IL-1 family of cytokines in 24 patients with CIDP, 13 patients with AIDP and 27 healthy subjects. We detected higher levels of IL-38 in CIDP patients compared with controls. When assessing study subgroups based on gender, there were no significant differences in IL-38 levels among the three female subgroups (P = 0.14). However, the difference among male subgroups was significant (P = 0.010). A Tukey test showed significant differences between male CIDP patients and male controls (P = 0.014). Considering the proposed anti-inflammatory role of IL-38, higher levels of this cytokine in CIDP might reflect the presence of a compensatory mechanism to reduce inflammatory processes in these patients. Further longitudinal assessment of this cytokine is need to test this hypothesis.

The effectiveness and safety of acupuncture therapy for Guillain-Barré syndrome: A systematic review and meta-analysis protocol

BACKGROUND

Guillain-Barré syndrome (GBS) is the most common acute paralytic neuropathy. Many clinical trials indicate acupuncture provides a good effect as a complementary therapy of Western medicine for GBS. The objective of this systematic review protocol is to provide the evidence to evaluate the effectiveness and safety of acupuncture on the treatment of GBS.

METHODS

We will search relevant randomized controlled trials investigating the effect of acupuncture for GBS in following databases from start to October 2019: PubMed, Embase, the Cochrane Library, CINAHL Complete, National Digital Science Library, China National Knowledge Infrastructure, and Wanfang Database without language restriction. For articles that meet our inclusion criteria, 2 researchers will extract the data information independently, and assess the risk of bias and trial quality by the Cochrane collaboration's tool. All data will be analyzed by RevMan V.5.3.3 statistical software.

RESULTS

According to the Barthel index of Activities of Daily Living (ADL) and the Medical Research Council (MRC) muscle scale, the efficacy and safety of acupuncture for GBS will be determined in this study.

CONCLUSION

This systemic review will provide high quality evidence to judging whether acupuncture provides benefits to treat GBS.Prospero registration number: CRD42019158710.

Therapeutic Plasma Exchange in Guillain-Barre Syndrome and chronic inflammatory demyelinating polyradiculoneuropathy

Therapeutic plasma exchange (TPE) has been used as a treatment modality in many autoimmune disorders, including neurological conditions, such as Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The American Society for Apheresis (ASFA) publishes its guidelines on the use of therapeutic apheresis every 3 years based on published evidence to assist physicians with both the medical and technical aspects of apheresis consults. The ASFA Guidelines included the use of TPE in both GBS and CIDP as an acceptable first-line therapy, either alone and/or in conjunction with other therapeutic modalities. In this article, we briefly reviewed GBS and CIDP, discussed the role of apheresis in these conditions as well as various technical aspects of the TPE procedure, such as apheresis calculation, number of volume exchange, replacement fluid, and management of potential complications.

Acute flaccid myelitis associated with enterovirus D68 in a non-epidemic setting

Acute flaccid myelitis (AFM) is a recently defined clinical disease accompanied by the national outbreak of enterovirus D68 (EV-D68) in the United States during the late summer/fall of 2014; 258 cases of EV-D68 and 59 cases of AFM were reported in Japan during the late summer/fall of 2015. Subsequently, there have been no epidemics of AFM or EV-D68. However, we encountered a patient who had AFM associated with EV-D68 in 2017. This is the first case of AFM caused by EV-D68 after the 2015 epidemic, and the only reported case in 2017. This report indicates that AFM caused by EV-D68 can arise even in non-epidemic situations. If a patient presents with paralysis, AFM caused by EV-D68 should be included in the differential diagnosis, regardless of the absence of an epidemic of EV-D68 infection.

Abnormal Osmolality Gap Exists in Distal Symmetric Polyneuropathy

Distal symmetric polyneuropathy, represented by chronic inflammatory demyelinating polyneuropathy, is a popular neurological condition. Some cases are known to be associated with genetic mutations or serum auto-antibodies, but the exact mechanisms in most cases are unknown. Recently, osmotic factors have been suggested to trigger some neurological disorders, such as neuromyelitis optica. The aim of the present study was to assess the possible association of osmotic factors in the pathogenesis of distal polyneuropathy. We prospectively measured the serum levels of osmolality, electrolytes, total protein, albumin, blood urea nitrogen, glucose, and osmolality gap in the patients with acute distal polyneuropathy before treatments (n = 12) and those with other comprehensive neurological disorders such as multiple sclerosis and neurodegenerative diseases (n = 176). Then, we compared each osmotic fraction between the two groups. As a result, all of the 12 patients with acute distal polyneuropathy, including 4 patients with chronic inflammatory demyelinating polyneuropathy, showed abnormally high or low values of osmolality gap, compared to the others (p < 0.0001, F-test). In the patients with other diseases, there were 2 patients with abnormally high osmolality gap values, which were attributable to their hyperlipidemia or high titer of serum autoantibody unrelated to polyneuropathy. In conclusion, serum osmolality gap would be elevated or decreased in the acute phase of distal symmetric polyneuropathy. Osmotic imbalance between the serum and nerve cells, based on abnormal excess or deficit of some unidentified serum osmolytes, may be one of the mechanisms in symmetric polyneuropathy with unknown causes.

Restoring Axonal Function with 4-Aminopyridine: Clinical Efficacy in Multiple Sclerosis and Beyond

The oral potassium channel blocker 4-aminopyridine has been used in various neurological conditions for decades. Numerous case reports and studies have supported its clinical efficacy in ameliorating the clinical presentation of certain neurological disorders. However, its short half-life, erratic drug levels, and safety-related dose restrictions limited its use as a self-compounded drug in clinical practice. This changed with the introduction of a prolonged-release formulation, which was successfully tested in patients with multiple sclerosis. It was fully approved by the US FDA in January 2010 but initially received only conditional approval from the European Medicines Agency (EMA) in July 2011. After additional clinical studies, this conditional approval was changed to unrestricted approval in August 2017. This article reviews and discusses these recent studies and places aminopyridines and their clinical utility into the context of a broader spectrum of neurological disorders, where clinical efficacy has been suggested. In 2010, prolonged-release 4-aminopyridine became the first drug specifically licensed to improve walking in patients with multiple sclerosis. About one-third of patients across disease courses benefit from this treatment. In addition, various reports indicate clinical efficacy beyond multiple sclerosis, which may broaden its use in clinical practice.

Immune-mediated Neuropathies Our Experience over 3 Years

Introduction

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

Patients and Methods

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

Results

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

Discussion

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

Conclusion

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

Associated conditions in small fiber neuropathy - a large cohort study and review of the literature

BACKGROUND AND PURPOSE

Small fiber neuropathy (SFN) is a common disorder leading to neuropathic pain and autonomic symptoms. The objective of this study was to investigate associated conditions in a large cohort of SFN patients and compare the prevalence to healthy individuals.

METHODS

A total of 921 patients with pure SFN were screened according to a standardized comprehensive diagnostic algorithm and compared with literature findings.

RESULTS

No associated condition could be found in 53% of the patients. Autoimmune diseases, sodium channel gene mutations, diabetes mellitus including glucose intolerance, and vitamin B12 deficiencies were more prevalent than reported literature findings, followed by alcohol abuse, chemotherapy, monoclonal gammopathy of undetermined significance, and haemochromatosis. In patients who were already known with a possible underlying condition at screening, additional underlying conditions were still found in another 26.7% of patients.

CONCLUSIONS

Based on these results, it is recommended that patients with pure SFN are screened at least for autoimmune diseases, sodium channel gene mutations, diabetes mellitus including glucose intolerance, and vitamin B12 deficiency, even when they already have a potential underlying condition at referral.

Immunoproteomic identification of antigenic candidate Campylobacter jejuni and human peripheral nerve proteins involved in Guillain-Barré syndrome

Immunoproteomics is become a potent methodology used for identifying immunoreactive proteins. In this study, an immunoproteomic approach based on 2-dimensional gel electrophoresis (2D-PAGE) and immunoblotting combined with high resolution mass spectrometry (MS) was used to identify immunoreactive proteins that might be involved in mechanisms of Guillain-Barré syndrome (GBS) development, regardless of their potential reciprocal molecular mimicry. Proteins isolated from C. jejuni and human peripheral nerve tissue (HPN) were separated with 2D SDS-PAGE and subjected to western blotting using serum samples from GBS patients. The peptides generated after proteolysis of the immunoreactive proteins were submitted to nanoflow-high performance liquid chromatography-nano electrospray ionization coupled to high resolution mass spectrometry (nHPLC-nESI-MS and MS/MS) followed by SEQUESTdata analysis for proteins identification. In C. jejuni, immunoreactivity was found for GroEL and DnaK, structural proteins (MOMP), key enzymatic proteins necessary for the microbial proliferation (adenylate kinase, enolase, inorganic pyrophosphatase and aspartate ammonia-lyase), and antioxidant enzymes (alkyl hydroperoxide reductase-AhpC and DNA protection during starvation protein - DNA protection factor against Fe²⁺-mediated oxidative stress). HPN immunoreactive proteins identified were heat shock proteins (HSP), intermediate filaments (vimentin and desmin), and other proteins and enzymes such as troponin/tropomyosin complex and ATP synthase subunit beta and the keratan sulfate proteoglycan lumican. The targeting of vimentin and desmin, suggested that the neuronal autoimmune damage is specifically directed to intermediate neuronal (vimentin) and neuromuscular IF, probably localized nearby cell surface, affording increased accessibility to autoantibodies. These findings suggest that the post-infectious development of GBS may be also associated to additional concomitant immune factors that lead to nerve damage generated by auto-immune trigger(s) different from molecular mimicry.

Immune-Mediated Autonomic Neuropathies following Allogeneic Stem Cell Transplantation in Acute Myeloid Leukemia

Background/Aims

Autonomic dysfunction (AD) after allogeneic stem cell transplant (SCT) is a rare occurrence and likely immune-mediated in etiology. There is limited literature on this topic and hence, we wish to briefly describe management of two cases at our institution and their outcomes.

Methods

We retrospectively identified two patients with immune-mediated AD after SCT from our database. Immune-mediated AD was defined as AD secondary to an immune-mediated etiology without an alternative cause and responding to immunosuppression.

Results

The first case is of a 32-year-old man with acute myeloid leukemia (AML) who underwent double umbilical cord allogeneic SCT. The second patient was a 51-year-old woman with secondary AML who underwent matched-related donor allogeneic SCT. Both underwent an extensive work-up for an underlying etiology prior to treatment with intravenous immunoglobulin (IVIG).

Conclusions

AD after SCT is a rare yet significant clinical entity. A work-up of underlying etiology should be performed. IVIG is a treatment option for these patients.

Immune-Mediated Neuropathies following Autologous Stem Cell Transplantation for Multiple Myeloma: Case Series and Review of the Literature

Neuropathy is a common finding in patients with multiple myeloma. Several different factors can cause neuropathy in these patients, such as the underlying disease itself, medications used for treatment, or immune-mediated processes. Immune-mediated neuropathies (IMN) consist of a heterogeneous spectrum of peripheral nerve disorders. Although IMN is associated with several hematological disorders, it remains a very rare complication of hematopoietic stem cell transplantation (HCT). We describe our experiences of 3 patients with multiple myeloma who experienced IMN following autologous HCT (auto-HCT). These 3 patients were felt to have IMN clearly attributable to auto-HCT because of a clear temporal association with auto-HCT and absence of any other obvious causative factor. The variety in their clinical presentations, diagnostic approach, and approaches to management are explained. The pathophysiology of how HCT may predispose to IMN remains poorly understood. Our report helps highlight several potential causes of this phenomenon, such as a paraneoplastic syndrome, immune reconstitution syndrome, or drug toxicity. We emphasize that a comprehensive approach is needed to address this rare entity, and that there should be a low threshold to initiate immune-specific therapy, such as plasmapheresis, if symptoms do not resolve spontaneously.

Treatment-related Fluctuations in Guillain Barre Syndrome and the Conundrum of Additional Cycles of Plasmapheresis

Introduction:

In Guillain Barre syndrome (GBS), worsening of weakness or disability after initial period of recovery or stabilization is described as treatment-related fluctuations (TRF).

Aim:

This study aims to describe the clinical characteristics and outcome of six patients with GBS and TRF.

Patients and Methods:

Six patients with GBS fulfilling NINCDS criteria, evaluated at a tertiary care university hospital during 2008–2017, were diagnosed to have TRF. They form the basis of this report.

Results:

All patients were men and their mean age was 40 years. At presentation, mean duration of illness was 15 days; the illness had plateaued in three and progressive in other three patients. Two of the four patients had variant GBS. Initially, five patients were treated with large volume plasmapheresis (LVPP) and one patient with methyl prednisolone. At 17–28 days after disease onset, three patients developed new neurologic deficits (bilateral facial paresis in two; paralytic ileus in one). Other three patients with worsening of limb weakness (medical research council sum score of >5) and disability (Hughes disability grade by ≥1) fulfilled Kleyweg's criteria for TRF. All the six patients were treated with the completion of five cycles or additional cycles of LVPP.

Conclusion:

Awareness about TRF is essential for correct diagnosis and management of patients with GBS.

Loss of Schwann cell plasticity in chronic inflammatory demyelinating polyneuropathy (CIDP)

Background

Chronic inflammatory demyelinating polyneuropathy (CIDP) is often associated with chronic disability, which can be accounted to incomplete regeneration of injured axons. We hypothesized that Schwann cell support for regenerating axons may be altered in CIDP, which may account for the poor clinical recovery seen in many patients.

Methods

We exposed human and rodent Schwann cells to sera from CIDP patients and controls. In a model of chronic nerve denervation, we transplanted these conditioned Schwann cells intraneurally and assessed their capacity to support axonal regeneration by electrophysiology and morphometry.

Results

CIDP-conditioned Schwann cells were less growth supportive for regenerating axons as compared to Schwann cells exposed to control sera. The loss of Schwann cell support was associated with lower levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) in CIDP sera and correlated with altered expression of c-Jun and p57kip2 in Schwann cells. The inactivation of these regulatory factors resulted in an altered expression of neurotrophins including BDNF, GDNF, and NGF in CIDP-conditioned Schwann cells in vitro.

Conclusions

Our study provides evidence that pro-regenerative functions of Schwann cells are affected in CIDP. It thereby offers a possible explanation for the clinical observation that in many CIDP patients recovery is incomplete despite sufficient immunosuppressive treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0711-7) contains supplementary material, which is available to authorized users.

The almost-invisible perineurioma

Intraneural perineurioma is a rare, benign slow-growing lesion arising from the perineurial cells that surrounds the peripheral nerve fibers. Typically it presents during childhood and young adulthood as a motor mononeuropathy. MRI plays an essential role in the diagnosis and localization of the lesion, which appears as a fusiform enlargement of the nerve fascicles that enhances intensely with gadolinium. Despite the typical clinical and radiological features, intraneural perineurioma remains largely underdiagnosed because of the lack of familiarity with this entity, but also as a result of technical limitations with conventional MRI that is typically performed as a screening test over a large field of view and without contrast sequences. The purpose of this article is to present the pitfalls and pearls learned from years of experience in the diagnosis and management of this relatively rare condition. Clinical suspicion and detailed neurological examination followed by high-quality electrophysiological studies (EPS) must lead to an adequate preimaging localization of the lesion and narrowing of the imaging area. The use of high-resolution (3-T) MRI combined with gadolinium administration will allow adequate visualization of the internal anatomy of the nerve and help in differentiating other causes of neuropathy. In cases where the lesion is not recognized but clinical suspicion is high, possible errors must be assessed, including the EPS localization, area of imaging, MRI resolution, and slice thickness.

Lymphoma-associated dysimmune polyneuropathies

Lymphoma consists of a variety of malignancies of lymphocyte origin. A spectrum of clinical peripheral neuropathy syndromes with different disease mechanisms occurs in about 5% of lymphoma patients. There exists a complex inter-relationship between lymphoproliferative malignancies and autoimmunity. An imbalance in the regulation of the immune system presumably underlies various immune-mediated neuropathies in patients with lymphoma. This article reviews lymphoma and more-or-less well-defined dysimmune neuropathy subgroups that are caused by humoral and/or cell-mediated immune disease mechanisms directed against known or undetermined peripheral nerve antigens.

Treatment of chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a sporadically occurring, acquired neuropathic condition of autoimmune origin with chronic progressive or relapsing-remitting disease course. CIDP is a treatable disorder; a variety of immunosuppressive and immunomodulatory agents are available to modify, impede, and even reverse the neurological deficits and sequelae that manifest in the course of the disease. However, in many cases CIDP is not curable. Challenges that remain in the treatment of CIDP patients are well recognized and include a remarkably individual heterogeneity in terms of disease course and treatment response as well as a lack of objective and feasible measures to predict and monitor the responsiveness to the available therapies. In this chapter an overview of the currently used drugs in the treatment of CIDP patients is given and some important and controversial issues that arise in the context of care for CIDP patients are discussed.

[Differential diagnostics of diseases of the brachial plexus]

Progressive, atrophic, asymmetrically distributed flaccid paresis of arm and hand muscles represents a frequent symptom of neuromuscular diseases that can be attributed to injury of the arm nerves, the plexus or the cervical roots. A timely and exact diagnosis is mandatory; however, the broad spectrum of differential diagnoses often represents a diagnostic challenge. A large variety of neuromuscular disorders need to be considered, encompassing autoimmune mediated inflammatory neuropathic conditions, such as multifocal motor neuropathy, as well as chronic degenerative and nerve compression disorders. This review provides an overview of the most frequent disorders of the upper plexus and cervical roots and summarizes the characteristic clinical features as well as electrodiagnostic and laboratory test results. In addition the diagnostic value of magnetic resonance imaging and sonography is discussed.

Neurofascin as a target for autoantibodies in peripheral neuropathies

OBJECTIVES

We asked whether autoantibodies against neurofascin (NF)186 or NF155, both localized at the nodes of Ranvier, are present in serum of patients with inflammatory neuropathy, and whether NF-specific monoclonal antibodies are pathogenic in vivo.

METHODS

We cloned human NF155 and NF186, and developed an ELISA and cell-based assay to screen for antibodies to human NF in a total of 434 donors including 294 patients with Guillain-Barré syndrome variants acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy, and chronic inflammatory demyelinating polyneuropathy (CIDP). We characterized reactive samples by isotyping, tissue section staining, and epitope mapping. We also injected NF-specific monoclonal antibodies IV into rats with experimental autoimmune neuritis.

RESULTS

We detected autoantibodies to NF by ELISA in 4% of patients with AIDP and CIDP, but not in controls. Most positive samples contained immunoglobulin G (IgG)1, IgG3, or IgG4 antibodies directed to only one isoform of NF. Two patients with CIDP showed particularly high (1:10,000 dilution) NF155-specific reactivity in both assays and stained paranodes. Two other patients with CIDP who benefited from plasma exchange exhibited antibodies to NF155 by ELISA, and upon affinity purification, antibodies to both isoforms were observed by both assays. Anti-NF monoclonal antibodies enhanced and prolonged induced neuritis in rats.

CONCLUSIONS

Autoantibodies to NF are detected in a very small proportion of patients with AIDP and patients with CIDP, but may nevertheless be pathogenic in these cases.

Kinetics of tissue iron in experimental autoimmune encephalomyelitis in rats

To elucidate the role of iron in the pathomechanisms of autoimmune CNS disorders, we estimated the tissue concentrations of Fe(2+) in the brain, spinal cord, and liver in the chronic relapsing form of experimental autoimmune encephalomyelitis (EAE). The disease was induced in Dark Agouti (DA) strain of rats, by subcutaneous injection of bovine brain homogenate in complete Freund's adjuvant (CFA). Control rats consisted of unsensitized rats and of rats treated with CFA or saline. The data obtained by clinical assessment and by inductively coupled plasma spectrometry have shown that the attacks of disease (on the 12th and 22nd post-immunization day) were followed by high accumulation of iron in the liver. Additionally, during the second attack of disease, the decreased concentration of Fe(2+) was found in cervical spinal cord. The data point to regulatory effects of iron and hepatic trace elements regulating mechanisms in the pathogenesis of EAE.

Plasma exchange and intravenous immunoglobulins: mechanism of action in immune-mediated neuropathies

Immune-mediated neuropathies are a heterogeneous group of peripheral nerve disorders, which are classified by time course, clinical pattern, affected nerves and pathological features. Plasma exchange (PE) and intravenous immunoglobulins (IVIg) are mainstays in the treatment of immune-mediated neuropathies. Of all treatments currently used, IVIg has probably the widest application range in immune-mediated neuropathies and efficacy has been well documented in several randomized controlled trials for Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP). Beneficial effects of IVIg have also been proven for multifocal motor neuropathy (MMN). Likewise, PE is an established treatment for GBS and CIDP, whereas it is considered to be ineffective in MMN. Different mechanisms of action are sought to be responsible for the immunemodulatory effect of PE and IVIg in autoimmune disorders. Some of those might be important for immune-mediated neuropathies, while others are probably negligible. The aim of this review is to summarize the recent advances in elucidating disease-specific mechanisms of actions of PE and IVIg in the treatment of immune-mediated neuropathies.