Immune-mediated neuropathies following stem cell transplantation

Clinical Presentation, Management, and Outcome in Neurolymphomatosis: A Systematic Review

BACKGROUND AND OBJECTIVES

Neurolymphomatosis (NL) refers to lymphomatous infiltration of the peripheral nervous system (PNS). NL diagnosis and treatment are challenging given the broad differential diagnosis of peripheral neuropathy, the lack of larger cohorts, and the subsequent unavailability of prognostic factors or consensus therapy. This study aimed to define characteristics and prognostic factors of NL.

METHODS

A systematic review of the literature (2004-2023) was performed using PubMed and Scopus databases and reported following PRISMA guidelines. Studies reporting individual patient data on cases with definitive NL diagnosis were included. Clinical, radiologic, pathologic, and outcome information were extracted. Univariable and multivariable survival analyses were performed using log-rank tests and Cox proportional hazard models.

RESULTS

A total of 459 NL cases from 264 studies were accumulated. NL was the first manifestation of malignancy (primary NL) in 197 patients. PNS relapse of known non-Hodgkin lymphoma (secondary NL) occurred in 262 cases after a median 12 months. NL predominantly presented with rapidly deteriorating, asymmetric painful polyneuropathy. Infiltrated structures included peripheral nerves (56%), nerve roots (52%), plexus (33%), and cranial nerves (32%). Diagnosis was established at a median of 3 months after symptom onset with substantial delays in primary NL. It mainly relied on PNS biopsy or FDG-PET, which carried high diagnostic yields (>90%). Postmortem diagnoses were rare (3%). Most cases were classified as B-cell (90%) lymphomas. Tumor-directed therapy was administered in 96% of patients and typically consisted of methotrexate or rituximab-based polychemotherapy. The median overall survival was 18 months. Primary NL without concurrent systemic disease outside the nervous system (hazard ratio [HR]: 0.44; 95% CI 0.25-0.78; p = 0.005), performance status (ECOG <2, HR: 0.30; 95% CI 0.18-0.52; p < 0.0001), and rituximab-based treatment (HR: 0.46; 95% CI 0.28-0.73; p = 0.001) were identified as favorable prognostic markers on multivariable analysis when adjusting for clinical and sociodemographic parameters.

DISCUSSION

Advances in neuroimaging modalities, particularly FDG-PET, facilitate NL diagnosis and offer a high diagnostic yield. Yet, diagnostic delays in primary NL remain common. Rituximab-based therapy improves NL outcome. Findings may assist clinicians in early recognition, prognostic stratification, and treatment of NL.

Progressive demyelinating polyneuropathy after hematopoietic cell transplantation in metachromatic leukodystrophy: a case series

Metachromatic leukodystrophy (MLD) is a neuro-metabolic disorder due to arylsulfatase A deficiency, causing demyelination of the central and peripheral nervous system. Hematopoietic cell transplantation (HCT) can provide a symptomatic and survival benefit for pre-symptomatic and early symptomatic patients by stabilizing CNS disease. This case series, however, illustrates the occurrence of severely progressive polyneuropathy shortly after HCT in two patients with late-infantile, one with late-juvenile, and one with adult MLD, leading to the inability to walk or sit without support. The patients had demyelinating polyneuropathy before HCT, performed at the ages of 2 years in the first two patients and at 14 and 23 years in the other two patients. The myeloablative conditioning regimen consisted of busulfan, fludarabine and, in one case, rituximab, with anti-thymocyte globulin, cyclosporine, steroids, and/or mycophenolate mofetil for GvHD prophylaxis. Polyneuropathy after HCT progressed parallel with tapering immunosuppression and paralleled bouts of infection and graft-versus-host disease (GvHD). Differential diagnoses included MLD progression, neurological GvHD or another (auto)inflammatory cause. Laboratory, electroneurography and pathology investigations were inconclusive. In two patients, treatment with immunomodulatory drugs led to temporary improvement, but not sustained stabilization of polyneuropathy. One patient showed recovery to pre-HCT functioning, except for a Holmes-like tremor, for which a peripheral origin cannot be excluded. One patient showed marginal response to immunosuppressive treatment and died ten months after HCT due to respiratory failure. The extensive diagnostic and therapeutic attempts highlight the challenge of characterizing and treating progressive polyneuropathy in patients with MLD shortly after HCT. We advise to consider repeat electro-neurography and possibly peripheral nerve biopsy in such patients. Nerve conduction blocks, evidence of the presence of T lymphocytes and macrophages in the neuronal and surrounding nerve tissue, and beneficial effects of immunomodulatory drugs may indicate a partially (auto)immune-mediated pathology. Polyneuropathy may cause major residual disease burden after HCT. MLD patients with progressive polyneuropathy could potentially benefit from a more intensified immunomodulatory drug regime following HCT, especially at times of immune activation.

Towards a Better Understanding of the Atypical Features of Chronic Graft-Versus-Host Disease: A Report from the 2020 National Institutes of Health Consensus Project Task Force

Alloreactive and autoimmune responses after allogeneic hematopoietic cell transplantation can occur in non-classical chronic graft-versus-host disease (chronic GVHD) tissues and organ systems or manifest in atypical ways in classical organs commonly affected by chronic GVHD. The National Institutes of Health (NIH) consensus projects were developed to improve understanding and classification of the clinical features and diagnostic criteria for chronic GVHD. While still speculative whether atypical manifestations are entirely due to chronic GVHD, these manifestations remain poorly captured by the current NIH consensus project criteria. Examples include chronic GVHD impacting the hematopoietic system as immune mediated cytopenias, endothelial dysfunction, or as atypical features in the musculoskeletal system, central and peripheral nervous system, kidneys, and serous membranes. These purported chronic GVHD features may contribute significantly to patient morbidity and mortality. Most of the atypical chronic GVHD features have received little study, particularly within multi-institutional and prospective studies, limiting our understanding of their frequency, pathogenesis, and relation to chronic GVHD. This NIH consensus project task force report provides an update on what is known and not known about the atypical manifestations of chronic GVHD, while outlining a research framework for future studies to be undertaken within the next three to seven years. We also provide provisional diagnostic criteria for each atypical manifestation, along with practical investigation strategies for clinicians managing patients with atypical chronic GVHD features.

Clinical risk factors and prognostic model for idiopathic inflammatory demyelinating diseases after haploidentical hematopoietic stem cell transplantation in patients with hematological malignancies

Idiopathic inflammatory demyelinating diseases (IIDDs) of the central nervous system (CNS) are rare but serious neurological complications of haploidentical hematopoietic stem cell transplantation (haplo-HSCT). However, the risk factors and a method to predict the prognosis of post-transplantation CNS IIDDs are not available. This retrospective study first reviewed data from 4532 patients who received haplo-HSCT during 2008-2019 in our center, and 184 patients (4.1%) with IIDDs after haplo-HSCT were identified. Grades II to IV acute graft-versus-host disease (aGVHD) (p < 0.001) and chronic GVHD (cGVHD) (p = 0.009) were identified as risk factors for developing IIDDs after haplo-HSCT. We then divided the 184 IIDD patients into a derivation cohort and validation cohort due to transplantation time to develop and validate a model for predicting the prognosis of IIDDs. In the multivariate analysis of the derivation cohort, four candidate predictors were entered into the final prognostic model: cytomegalovirus (CMV) infection, Epstein-Barr virus (EBV) infection, IgG synthesis (IgG-syn) and spinal cord lesions. The prognostic model had an area under the receiver operating characteristic curve of 0.864 (95% CI: 0.803-0.925) in the internal validation cohort and 0.871 (95% CI: 0.806-0.931) in the external validation cohort. The calibration plots showed a high agreement between the predicted and observed outcomes. Decision curve analysis indicated that IIDD patients could benefit from the clinical application of the prognostic model. The identification of IIDD patients after allo-HSCT who have a poor prognosis might allow timely treatment and improve patient survival and outcomes.

Tumefactive demyelination in pediatrics: An unusual late neurological complication of hematopoietic stem cell transplant

Immune-mediated demyelination is a rare posttransplant complication. Here, we report an 8.5-year-old boy who developed left hemiparesis, 18 months post matched sibling donor hematopoietic stem cell transplant (HSCT) for relapsed acute myeloid leukemia and was diagnosed to have tumefactive demyelination. The diagnosis was established based on clinical and radiological features. The complete resolution of the lesions with steroids further established the immune-mediated pathophysiology.

Iatrogenic immune-mediated neuropathies: diagnostic, epidemiological and mechanistic uncertainties for causality and implications for clinical practice

Acute and chronic immune-mediated neuropathies have been widely reported with medical intervention. Although causal relationship may be uncertain in many cases, a variety of drugs, several vaccination types, surgical procedures and bone marrow transplants have been reported as possible cause or trigger of a putative immune-mediated response resulting in acute and chronic neuropathies. We conducted a systematic review of the literature from 1966 to 2020 on reported cases of possible iatrogenic immune-mediated neuropathies. We determined in each case the likelihood of causality based on frequency of the association, focusing primarily on clinical presentation and disease course as well as available ancillary investigations (electrophysiology, blood and cerebrospinal fluid and neuropathology). The response to immunotherapy and issue of re-exposure were also evaluated. We also considered hypothesised mechanisms of onset of immune-mediated neuropathy in the specific iatrogenic context. We believe that a likely causal relationship exists for only few drugs, mainly antitumour necrosis factor alpha agents and immune checkpoint inhibitors, but remains largely unsubstantiated for most other suggested iatrogenic causes. Unfortunately, given the lack of an accurate diagnostic biomarker for most immune-mediated neuropathies, clinical assessment will often override ancillary investigations, resulting in lower levels of certainty that may continue to cast serious doubts on reliability of their diagnosis. Consequently, future reports of suspected cases should collect and exhaustively assess all relevant data. At the current time, besides lack of evidence for causality, the practical implications on management of suspected cases is extremely limited and therapeutic decisions appear likely no different to those made in non-iatrogenic cases.

Severe allo-immune antibody-associated peripheral and central nervous system diseases after allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a curative treatment for hematologic malignancies. Acute and chronic graft-versus-host disease (GvHD) are the major immune-mediated complications after alloHSCT. However, there is controversy whether neurologic complications after alloHSCT might represent manifestations of GvHD. We report three patients who acquired distinct, severe immune-mediated peripheral or central nervous system diseases after alloHSCT without other, concomitant GvHD manifestations. One patient had been diagnosed with B-cell chronic lymphocytic leukemia and two patients with high risk myelodysplastic syndrome. Patient #1 presented as LGI1- and GAD-IgG positive immune-mediated encephalitis, patient #2 was diagnosed with MOG-IgG positive encephalomyelitis, and patient #3 had chronic inflammatory polyneuropathy associated with SSA(Ro)-IgG positive Sjögren's syndrome. 100% donor chimerism was detectable in the peripheral blood in all three. The specific antibodies were undetectable in donors' and patients' blood before alloHSCT suggesting that the antibodies had arisen from the transplanted donor immune system. Early intensive immunotherapy led to improvement of clinical symptoms and stability of the neurological disease, however, at the cost of losing the graft-versus-malignancy effect in one patient. In conclusion, we provide evidence of isolated, severe allo-immune diseases of the peripheral and central nervous system as complications of alloHSCT ("neuro-GvHD"). Interdisciplinary surveillance and thorough diagnostic work-up are needed for early diagnosis and treatment of neuro-immunologic complications after alloHSCT to improve the otherwise poor outcome.

Noninvasive tools based on immune biomarkers for the diagnosis of central nervous system graft-vs-host disease: Two case reports and a review of the literature

BACKGROUND

Central nervous system graft-vs-host disease (CNS-GVHD) is a rare cause of CNS disorders after allogeneic hematopoietic stem cell transplantation. Currently, establishing a diagnosis of CNS-GVHD is challenging because the diagnostic criteria and diagnostic methods are not well defined and many confounding factors need to be ruled out.

CASE SUMMARY

Here, we present two patients with CNS-GVHD. Both patients with a history of acute GVHD or chronic GVHD developed neurological symptoms that could not be explained by other causes, and had abnormal cerebrospinal fluid (CSF) studies as determined by CSF and blood immune biomarker examinations, suggestive of suspected CNS-GVHD. Due to the lack of specific magnetic resonance imaging abnormalities and the rapid clinical deterioration of the patients, we did not attempt to perform a brain biopsy, but prompted the initiation of empirical immunosuppressive therapy. In view of the rapid and favorable response to local and systematic immunosuppressive treatment and the aforementioned neurologic manifestations together with CSF abnormalities and other negative findings, a final diagnosis of CNS-GVHD was made.

CONCLUSION

CSF and blood immune biomarker examinations facilitated the diagnosis of CNS-GVHD, which are particularly suitable for patients who are critically ill and require urgent treatment and for those who are unsuitable for invasive diagnostic procedures.

Nerve Ultrasound as Helpful Tool in Polyneuropathies

Background: Polyneuropathies (PNP) are a broad field of diseases affecting millions of people. While the symptoms presented are mostly similar, underlying causes are abundant. Thus, early identification of treatable causes is often difficult. Besides clinical data and basic laboratory findings, nerve conduction studies are crucial for etiological classification, yet limited. Besides Magnetic Resonance Imaging (MRI), high-resolution nerve ultrasound (HRUS) has become a noninvasive, fast, economic and available tool to help distinguish different types of nerve alterations in neuropathies. Methods: We aim to describe typical ultrasound findings in PNP and patterns of morphological changes in hereditary, immune-mediated, diabetic, metabolic and neurodegenerative PNP. Literature research was performed in PubMed using the terms ‘nerve ultrasound’, neuromuscular ultrasound, high-resolution nerve ultrasound, peripheral nerves, nerve enlargement, demyelinating, hereditary, polyneuropathies, hypertrophy’. Results: Plenty of studies over the past 20 years investigated the value of nerve ultrasound in different neuropathies. Next to nerve enlargement, patterns of nerve enlargement, echointensity, vascularization and elastography have been evaluated for diagnostic terms. Furthermore, different scores have been developed to distinguish different etiologies of PNP. Conclusions: Where morphological alterations of the nerves reflect underlying pathologies, early nerve ultrasound might enable a timely start of available treatment and also facilitate follow up of therapy success.

GFAP IgG associated inflammatory polyneuropathy

BACKGROUND

GFAP (glial fibrillary acidic protein)-IgG is predominantly associated with meningoencephalomyelitis, and neuropathy presentations are rare.

METHODS

We reviewed clinical, electrodiagnostic and histopathological presentations of GFAP-IgG associated peripheral neuropathy.

RESULTS

We identified six cases, five of whom had peripheral neuropathy as the initial presentation. Acute/subacute polyradicluoneuropathy or proximal nerve involvement was a common presentation. Three had demyelinating neuropathies on electrophysiological studies. Nerve biopsies (n = 2) demonstrated T-cell predominant perivascular inflammatory collections, and all patients with clinical follow up responded favorably to immunotherapy.

CONCLUSION

GFAP neuropathy represents a potentially treatable immune-mediated neuropathy and can occur with or without co-existing meningoencephalomyelitis.

Incidence, Risk Factors, and Outcome of Immune-Mediated Neuropathies (IMNs) following Haploidentical Hematopoietic Stem Cell Transplantation

Immune-mediated neuropathies (IMNs) following hematopoietic stem cell transplantation have been described recently, which, excluding Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy, may present with atypical patterns. This retrospective, nested, case-control study reviewed data from 3858 patients who received haploidentical hematopoietic stem cell transplantation (haplo-HSCT) during the past 10 years at a single center, and 40 patients (1.04%) with IMN following haplo-HSCT were identified. Chronic graft-versus-host disease (cGVHD) (P = .043) and cytomegalovirus (CMV) viremia (P = .035) were recognized as independent risk factors for the development of IMN after haplo-HSCT. There were no significant differences in overall survival (P = .619), disease-free survival (P = .609), nonrelapse mortality (P = .87), or the incidence of relapse (P = .583) between patients with and without IMN after haplo-HSCT. However, patients with post-transplant IMN were at higher risk of developing cGVHD (P = .012) than patients who did not develop IMN. Twenty-four of the 40 patients with IMN (60%) attained neurologic improvement after treatments including vitamins B₁ and B₁₂ and/or immunomodulatory agents. However, 19 (47.5%) patients still had persistent motor/sensory deficits despite receiving timely treatment. More studies are needed to help develop standardized diagnostic and therapeutic strategies for patients with post-transplant IMN.

Peripheral Nervous System Involvement in Lymphoproliferative Disorders

Peripheral neuropathies are a vast group of diseases with heterogeneous aetiologies, including genetic and acquired causes. Several haematological disorders may cause an impairment of the peripheral nervous system, with diverse mechanisms and variable clinical, electrophysiological and pathological manifestations. In this practical review, we considered the main phenotypes of peripheral nervous system diseases associated with lymphoproliferative disorders.

The area of intersection of neurological and haematological fields is of particular complexity and raises specific problems in the clinical practice of lymphoproliferative disorders. The personal crosstalk between neurologists and haematologists remains a fundamental tool for a proper diagnostic process which may lead to successful treatments in most cases.

IgG synthesis rate and anti-myelin oligodendrocyte glycoprotein antibody in CSF may be associated with the onset of CNS demyelination after haplo-HSCT

Haploidentical hematopoietic stem cell transplant (haplo-HSCT) is an upfront and effective therapy for hematology patients, but it usually has many complications, such as neurological complications. As one of the neurological complications following haplo-HSCT, immune-mediated demyelinating diseases of the central nervous system (CNS) seriously affect a patient's quality of life. However, the incidence, risk factors, and pathogenesis of CNS demyelination are not very well understood. Thirty of the 1526 patients (1.96%) suffered from CNS demyelination. In univariate analysis, we found that blood-brain barrier (BBB) permeability and the CSF IgG synthesis index (IgG-Syn) were related to the occurrence of CNS demyelination (p < 0.05). In a multivariate analysis, the IgG-Syn (OR = 1.017, 95% CI 1.003-1.031, p = 0.019) and CSF anti-myelin oligodendrocyte glycoprotein antibody (MOG.Ab) (OR = 12.059, 95% CI 1.141-127.458, p = 0.038) were independently associated with the onset of CNS demyelination. We also studied the possible pathogenesis of CNS demyelination. Immune reconstitution (the cell proportions of CD19⁺ B cells, CD3⁺ T cells, and CD4⁺ T cells); the counts of leucocytes, lymphocytes, monocytes, and platelets; and the levels of immunoglobulins A, G, and M 30, 60, and 90 days after HSCT showed no significant differences between CNS demyelination and no demyelination (p > 0.05). The probabilities of overall survival showed no significant differences between patients with and without demyelination (p > 0.05). Only four deaths in 30 patients, but bringing projected survival to less than 20%.We imply that IgG-Syn and CSF MOG. Ab may be associated with the onset of CNS demyelination during 2 weeks of neurological symptoms in patients with brain or spinal cord MRI abnormality. Immune reconstitution may not be the pathogenesis of CNS demyelination.

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.

Cerebrospinal fluid findings in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathies

The classic immunologic alteration of the cerebrospinal fluid (CSF) in Guillain-Barré syndrome (GBS), albuminocytologic dissociation, has been known since the original paper by Guillain, Barré, and Strohl. Albuminocytologic dissociation has been also described in other forms of the GBS spectrum, such as axonal motor or motor-sensory forms (AMAN, AMSAN), the anti-GQ1b spectrum of Miller Fisher syndrome, and Bickerstaff brainstem encephalitis. Cytokines, chemokines, antibodies, complement components, and molecules with a putative neuroprotective role or indicating axonal damage have also been examined using different methods. Besides these candidate approaches, proteomics has been recently applied to discover potential biomarkers. The overall results support the immunopathogenesis of GBS, but albuminocytologic dissociation remained the only consistent CSF biomarker supporting the diagnosis of GBS. Chronic inflammatory neuropathies also comprise a heterogeneous group of diseases. Increased protein in the CSF is a supportive factor of chronic inflammatory demyelinating polyneuropathy, especially in the absence of definite electrophysiologic criteria. A number of other markers have also been investigated in the CSF of patients with chronic inflammatory neuropathies, similar to GBS. However, none has been used in supporting diagnosis, differentiating among syndromes, or predicting the clinical course and treatment responses.

Hypoxia-Inducible Factor 1-Alpha Regulates Cancer-Inhibitory Effect of Human Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have been shown to be able to inhibit cancer cells growth. In this study, we investigate the role and the molecular mechanism of hypoxia-inducible factor 1-alpha (HIF-1α) in inhibition of cancer cell proliferation by human MSCs through depletion and overexpression of HIF-1α in human MSCs. We found that the cell culture medium from HIF-1α-depleted Z3 cells significantly promotes breast cancer MCF-7 cell proliferation and colony formation. The expression of p21 is increased in MCF-7 cells, but p53 level remains unchanged. In contrast, the cultured medium from HIF-1α-overexpressed Z3 cells dramatically inhibits MCF-7 cell proliferation and colony formation. The expression of p21 is inhibited in MCF-7 cells, but p53 does not change. We conclude HIF-1α promotes inhibitory effect of human MCSs on breast cancer cell proliferation and colony formation. This process is tightly correlated with cell cycle protein p21 level in cancer cells.

Immune-Mediated Complications after Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) has an integral role in the treatment of malignant and nonmalignant diseases. Long-term complications after HSCT have been well established and include graft-versus-host disease (GVHD), conditioning regimen-related toxicities, disease relapse, and infections. Immune-mediated phenomena are increasingly described after HSCT with clinically significant sequelae. Diagnosis is challenging because of features that overlap with other commonly reported post-transplantation complications. Patients who experience immune-mediated disease after HSCT tend to have poor outcomes. Early recognition of immune-mediated complications is imperative to reduce preventable morbidity and mortality. This review looks at the currently available literature on pathogenesis, incidence, risk factors, treatment, and outcomes of immune-mediated disease (other than GVHD) after HSCT.

Bortezomib-associated demyelinating neuropathy--clinical and pathologic features

OBJECTIVES

Bortezomib is a proteasome inhibitor that is frequently used for multiple myeloma and lymphoma. A sensory predominant axonal neuropathy is associated with bortezomib treatment but a demyelinating neuropathy is also described primarily based on electrodiagnostic findings. We report a series of patients treated with bortezomib who developed peripheral neuropathy and were found to have demyelinating features on electrodiagnostic testing.

METHODS

Four patients who developed a bortezomib-induced peripheral neuropathy underwent electrophysiological testing, and 1 patient had a nerve biopsy.

RESULTS

The four patients with bortezomib-induced peripheral neuropathy had demyelinating features on their electrophysiological testing. The nerve biopsy performed in 1 patient demonstrated a demyelinating component in a background of axonal degeneration.

CONCLUSIONS

Although most toxic neuropathies are symmetrical axonal neuropathies, bortezomib is part of a small list of agents that may cause a demyelinating polyneuropathy and axonal degeneration. These findings have been confirmed by nerve biopsy.

Therapeutics targeting inflammation in the immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) is characterized by improvement in a previously incompetent human immune system manifesting as worsening of clinical symptoms secondary to the ability of the immune system to now mount a vigorous inflammatory response. IRIS was first recognized in the setting of human immunodeficiency virus, and this clinical setting continues to be where it is most frequently encountered. Hallmarks of the pathogenesis of IRIS, independent of the clinical presentation and the underlying pathogen, include excessive activation of the immune system, with increased circulating effector memory T cells, and elevated levels of serum cytokines and inflammatory markers. Patients with undiagnosed opportunistic infections remain at risk for unmasking IRIS at the time of active antiretroviral therapy (ART) initiation. Systematic screening for opportunistic infections before starting ART is a key element to prevent this phenomenon. Appropriate management of IRIS requires prompt recognition of the syndrome and exclusion of alternative diagnoses, particularly underlying infections and drug resistance. Controlled studies supporting the use of pharmacologic interventions in IRIS are scare, and recommendations are based on case series and expert opinions. The only controlled trial published to date, showed reduction in morbidity in patients with paradoxical tuberculosis-related IRIS with the use of oral corticosteroids. There are currently limited data to recommend other anti-inflammatory or immunomodulatory therapies that are discussed in this review, and further research is needed. Ongoing research regarding the immune pathogenesis of IRIS will likely direct future rational therapeutic approaches and clinical trials.

[2013: what's new in inflammatory neuropathies]

Several high-quality publications were published in 2013 and some major trials studies were started. In Guillain-Barré syndrome, events included the launch of IGOS and a better understanding of diagnostic limits, the effect of influenza vaccination, and better care, but uncertainty remains about analgesics. A new mouse model was also described. In chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), diagnostic pitfalls can be recalled. Our knowledge of underlying pathophysiological processes has improved, and the value of monitoring with function and deficit scores has been demonstrated. IVIG can sometimes be effective longer than expected, but CIDP remains sensitive to corticosteroids, particularly with the long-term beneficial effects of megadose dexamethasone. The impact of fingolimod remains to be demonstrated in an ongoing trial. Advances concerning multifocal motor neuropathy, inflammatory plexopathy, and neuropathy with anti -MAG activity are discussed but treatments already recognized as effective should not be changed. Imaging of peripheral nerve progresses.