Neurological complications following alemtuzumab-based reduced-intensity allogeneic transplantation

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.

Neurological complications in adult allogeneic hematopoietic stem cell transplant patients: Incidence, characteristics and long-term follow-up in a multicenter series

Neurological complications (NCs) represent a diagnostic and clinical challenge in allogeneic hematopoietic stem cell transplant (alloHSCT) patients. We retrospectively analyzed NC incidence, etiology, timing, characteristics, outcome, and long-term effects in 2384 adult patients transplanted in seven Italian institutions between January 2007 and December 2019. Ninety-three (3.9%) patients were affected by 96 NCs that were infectious (29.2%), immune/inflammatory (26%), drug-related (12.5%), cerebrovascular (5.2%), metabolic (3.1%), related to central nervous system disease relapse (11.5%) and malignancy (3.1%), or undefined (9.4%). Six patients (6.4%) had neurological manifestations of chronic graft-versus-host disease (GVHD). NCs occurred on average at day +128 (from -5 to +4063). Early (< day +120) and late NCs had similar frequencies (46.9% vs 53.1%, p = 0.39). Thirty-one patients (33.3%) were affected by acute or chronic GVHD at the NC onset. With a median follow-up of 25.4 (0.4-163) months, the overall mortality due to NCs was 22.6%. The median time between NC onset and death was 36 (1-269) days. Infectious NCs were the main cause (61.9%) of NC-related mortality. A persistent neurological impairment occurred in 20.4% patients, 57.9% of whom being affected by immune/inflammatory NCs. This study highlights the rare, yet severe impact of alloHSCT-associated NCs on patient survival and long-term functional ability.

Neurological complications following pediatric allogeneic hematopoietic stem cell transplantation: Risk factors and outcome

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (HSCT) is an efficient treatment for numerous malignant and nonmalignant conditions affecting children. This procedure can result in infectious and noninfectious neurological complications (NCs).

OBJECTIVE

The objective of the study is to examine the incidence, risk factors, and outcomes of NCs in pediatric patients following allogeneic HSCT.

METHODS

We performed a retrospective study of 746 children who underwent 943 allogeneic HSCTs in two large pediatric hospitals in Israel from January 2000 to December 2019.

RESULTS

Of the pediatric patients 107 (14.3%) experienced 150 NCs. The median follow-up was 55 months. Noninfectious NCs were more common than infectious NCs (81.3% vs. 18.7%). Factors significantly associated with type of NC (infectious vs. noninfectious) were underlying disease (immunodeficiency vs. malignant and metabolic/hematologic disease) (p-value = 0.000), and use of immunosuppressive agent, either Campath or ATG (p-value = 0.041). Factors with a significant impact on developing neurological sequelae post-NC were number of HSCT >1 (p-value = 0.028), the use of alemtuzumab as an immunosuppressive agent (p-value = 0.003), and infectious type of NC (p-value = 0.046). The overall survival rate of whole NC-cohort was 44%; one-third of all mortality cases were attributed to the NC. The strongest prognostic factors associated with mortality were older age at HSCT (p-value = 0.000), the use of alemtuzumab as an immunosuppressive agent (p-value = 0.004), and the existence of neurological sequelae (p-value = 0.000). Abnormal central nervous system imaging (p-value = 0.013), the use of alemtuzumab as an immunosuppressive agent (p-value = 0.019), and neurological sequelae (p-value = 0.000) had statistically significant effects on neurological cause of death.

CONCLUSION

Infectious and noninfectious NCs are a significant cause of morbidity and mortality following allogeneic HSCT in children. Further research is required to better understand the risk factors for different NCs and their outcomes regarding sequelae and survival.

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.

Immunosuppression-related neurological disorders in kidney transplantation

A large number of neurological disorders can affect renal transplant recipients, potentially leading to disabling or life-threatening complications. Prevention, early diagnosis and appropriate management of these conditions are critical to avoid irreversible lesions. A pivotal role in the pathogenesis of common post-transplant neurological disorders is played by immunosuppressive therapy. The most frequently administered regimen consists of triple immunosuppression, which comprises a calcineurin inhibitor (CNI), a purine synthesis inhibitor and glucocorticoids. Some of these immunosuppressive drugs may lead to neurological signs and symptoms through direct neurotoxic effects, and all of them may be responsible for the development of tumors or opportunistic infections. In this review, after a brief summary of neurotoxic pathogenetic mechanisms encompassing recent advances in the field, we focus on the clinical presentation of more common and severe immunosuppression-related neurological complications, classifying them by characteristics of urgency and anatomic site. Our goal is to provide a general framework that addresses such clinical issues with a multidisciplinary approach, as these conditions require.

Neurotoxicity of antibodies in cancer therapy: A review

The objective of this manuscript is to identify the neurological side effect profile associated with different classes of antibodies used in cancer pharmacotherapy and to estimate the frequency in which these neurotoxicity occurs. A systematic review of the literature was conducted using OVID MEDLINE and EMBASE databases for articles written between January of 2010 till August of 2018. The spectrum of neurotoxicity was searched using expanded terminology, medical subject headings, truncation, spelling variations and database specific controlled vocabulary. 2134 citations were retrieved that were narrowed down to 151 when SORT 1 or SORT 2 critical appraisal tool was applied to articles with human subjects. Meta-analysis using random effect model was done to estimate the prevalence of neurological symptoms per class of antibody described in SORT1 and SORT2 articles. It was found that the most common neurotoxicity per antibody class are as follows; Bi-specific T-cell engagers was headache 38% [35-40%; I² 0%]; anti-CD20, neuropathy, 16% [7-24%, I² 65%]; anti-CD30, neuropathy 57% [46-68%, I² 72%]; anti-CD52, neuropathy 5-15%; anti-CTL4, headache 12% [7-16%, I² 49%]; anti-EGFR, headache 25% [11-38%, I² 92%]; anti-Her2, neuropathy 33% [18-49%, I² 98%]; anti-PD1 and PDL1, headache 3% [2-5%, I² 85%]; and anti-VEGF, headache 25% [16-35%, I² 73%]. Therefore, all classes of antibodies used in cancer pharmacotherapy have associated neurotoxicity with a wide spectrum of effects afflicting the nervous system as a whole. The specific side effects and the frequency at which they occur differ per class of antibody. Broader and more severe symptoms were noted to effect patients with preexisting brain lesions.

Differential Interaction of Peripheral Blood Lymphocyte Counts (ALC) With Different in vivo Depletion Strategies in Predicting Outcomes of Allogeneic Transplant: An International 2 Center Experience

Dosing regimens for antithymocyte globulin (ATG) and anti-CD52 antibody (alemtuzumab) for graft vs. host disease prophylaxis (GVHD) are empiric or weight-based, and do not account for individual patient factors. Recently, it has been shown that recipient peripheral blood absolute lymphocyte count (ALC) on the day of ATG administration interacts with the dose of ATG administered to predict transplantation outcome. Similarly, we wanted to analyze if the recipient ALC interacts with alemtuzumab dosing to predict outcomes. We retrospectively compared 364 patients, 124 patients receiving ATG (anti-thymocyte globulin) for GVHD prophylaxis, and undergoing unrelated first allogeneic transplant for myeloid and lymphoid malignancies (group 1) to 240 patients receiving alemtuzumab (group 2), in similar time period. There was no difference in survival or acute and chronic GVHD between 60 and 100 mg of alemtuzumab dosing. Unlike ATG (where the pre-transplant recipient ALC interacted with ATG dose on day of its administration (day 1) to predict OS and DFS (p = 0.05), within alemtuzumab group, the recipient ALC on second day of alemtuzumab administration (day 2) and its interaction with alemtuzumab dose strongly predicted OS, DFS and relapse (p = 0.05, HR-1.81, 1.1–3.3; p = 0.002, HR-2.41, CI, 1.3–4.2; and p = 0.003, HR-2.78, CI, 1.4–5.2), respectively. ALC (day 2) of 0.08 × 10⁹/lit or higher, had a specificity of 96% in predicting inferior DFS. Like ATG, there is definite but differential interaction between the recipient peripheral blood ALC and alemtuzumab dose to predict OS, DFS, and relapses.

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.

Alemtuzumab-containing reduced intensity conditioning allogenic hematopoietic stem cell transplantation in a case of primary progressive multiple sclerosis

Increasing evidence has emerged lately regarding the use of autologous hematopoietic stem cell transplantation (HSCT) in the treatment of aggressive multiple sclerosis (MS). However, data is scarce regarding the use of allogenic HSCT in treating MS. We present a 42 years old male with aplastic anemia who underwent allogenic HSCT for severe aplastic anemia. This patient was diagnosed with primary progressive multiple sclerosis (PPMS) one-year post transplant and had to undergo a second HSCT due to his hematological disorder. His second HSCT was conditioned with an alemtuzumab containing regimen, after which his MRI and expanded disability status scale (EDSS) remained to be stable for 18 months.

Guillain-Barré syndrome after allogeneic bone marrow transplantation: Case report and literature review

A 50-year-old man with acute myelogenous leukemia underwent allogeneic bone-marrow transplantation (BMT). He presented with severe diarrhoea 86 days post BMT and was diagnosed with graft-versus-host disease (GVHD) based on skin and rectal biopsies. He complained of numbness and weakness in the distal extremities at 114 days after BMT. His symptoms rapidly deteriorated and he required mechanical ventilation for respiratory failure. His clinical course and the findings of a nerve conduction study fulfilled the criteria for diagnosis of Guillain-Barré syndrome (GBS). Sural nerve biopsy revealed active demyelination and infiltration of macrophages and CD8⁺ T-cells. After three cycles of intravenous immunoglobulin therapy, his symptoms gradually improved, and he could eventually walk unassisted. Although GBS has been known to develop after allogeneic BMT, the pathogenesis remains unclear, and specific treatment regimens have not been well established. Here, we report a case of GBS, caused by an immune-mediated mechanism related to GVHD, which was successfully treated using intravenous immunoglobulin therapy.

Chemotherapy-induced peripheral neurotoxicity in cancer survivors: an underdiagnosed clinical entity?

Systemic chemotherapy is a cornerstone of the modern medical management of cancer, although its use is limited by toxicity on normal tissues and organs, including the nervous system. Long-surviving or cured people strongly require a high level of wellness in addition to prolongation of life (the concept of the quality of survival), but neurologic dysfunction can severely affect daily life activities. Chemotherapy-related peripheral neurotoxicity is becoming one of the most worrisome long-term side effects in patients affected by a neoplasm. The central nervous system has a limited capacity to recover from injuries, and it is not surprising that severe damage can determine long-term or permanent neurologic dysfunction. However, the peripheral nervous system also can be permanently damaged by anticancer treatments despite its better regeneration capacities, and the effect on patients' daily life activities might be extremely severe. However, only recently, the paradigms of peripheral neurotoxicity reversibility have been scientifically challenged, and studies have been performed to capture the patients' perspectives on this issue and to measure the effect of peripheral neurotoxicity on their daily life activities. Despite these efforts, knowledge about this problem is still largely incomplete, and further studies are necessary to clarify the several still-unsettled aspects of long-term peripheral neurotoxicity of conventional and targeted anticancer chemotherapy.

Chemotherapy-induced peripheral neurotoxicity (CIPN): what we need and what we know

Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the most frequent and severe long-term side effects of cancer chemotherapy. Preclinical and clinical studies have extensively investigated CIPN searching for effective strategies to limit its severity or to treat CIPN-related impairment, but the results have been disappointing. Among the reasons for this failure are methodological flaws in both preclinical and clinical investigations. Their successful resolution might provide a brighter perspective for future studies. Among the several neurotoxic chemotherapy drugs, oxaliplatin may offer a clear example of a methodological approach eventually leading to successful clinical trials. However, the same considerations apply to the other neurotoxic agents and, although frequently neglected, also to the new "targeted" agents.

A comparative study of reduced dose alemtuzumab in matched unrelated donor and related donor reduced intensity transplants

In vivo T cell depletion with 100 mg alemtuzumab prevents graft-versus-host disease (GVHD) in reduced intensity conditioned transplants but is associated with delayed immune reconstitution, a higher risk of infection and relapse. De-escalation studies have shown that a reduced dose of 30 mg is as effective as 100 mg in preventing GVHD in matched related donor (MRD) transplants. Dose reduction in matched unrelated donor (MUD) transplants is feasible but the comparative efficacy of alemtuzumab in this setting is not known and opinions vary widely concerning the optimal level of GVHD prophylaxis that should be achieved. Through retrospective analysis we made an objective comparison of MUD transplants receiving an empirically reduced dose of 60 mg, with MRD transplants receiving a 30 mg dose. We observed proportionate levels of alemtuzumab according to dose but an inverse relationship with body surface area particularly in MRD transplants. MUD transplants experienced more acute and chronic GVHD, higher T cell chimerism, more sustained use of ciclosporin and less need for donor lymphocyte infusion than MRD transplants. Thus, doubling the dose of alemtuzumab to 60 mg did not provide equivalent prevention of GVHD after MUD transplant although there was no difference in non-relapse mortality or survival compared with MRD transplants.

Multifocal motor neuropathy: current therapies and novel strategies

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

Neurological complications of transplantation: part I: hematopoietic cell transplantation

Hematopoietic cell transplantation (HCT) is the preferred treatment for an expanding range of neoplastic and nonmalignant conditions. Increasing numbers of solid organ transplantations (SOTs) add an additional population of immunosuppressed patients with multiple potential neurological problems. While the spectrum of neurological complications varies with conditioning procedure and hematopoietic cell or solid organ source, major neurological complications occur with all transplantation procedures. This 2 part review emphasizes a practical consultative approach to central and peripheral nervous system problems related to HCT or SOT with clinical and neuroimaging examples from the authors' institutional experience with the following conditions: the diversity of manifestations of common infections such as varicella zoster virus, Aspergillus, and progressive multifocal leukoencephalopathy (PML), drug therapy-related complications, stroke mechanisms, the spectrum of graft versus host disease (GVHD), and neurologically important syndromes of immune reconstitution inflammatory syndrome (IRIS), posterior reversible encephalopathy syndrome (PRES), and posttransplantation lymphoproliferative disorder (PTLD). These complications preferentially occur at specific intervals after HCT and SOT, and neurological consultants must recognize an extensive spectrum of syndromes in order to effect timely diagnosis and expedite appropriate treatment.

Successful management with intravenous immunoglobulins in alemtuzumab-induced acute inflammatory demyelinating neuropathy: clinical report of three patients

Several neurological complications have been associated with the use of monoclonal antibodies (mAbs), and demyelinating disorders have been estimated to affect the 0.02-0.20% of treated patients. Alemtuzumab is a humanized chimeric mAbthat targets the CD52 antigen, it is currently approved for relapsed/refractory and high-risk untreated chronic lymphocytic leukemia (CLL). The major complication of alemtuzumab therapy is the increased risk of opportunistic infections secondary to the profound immunosuppression. Autoimmune diseases as Graves disease, immune thrombocytopenic purpura and Good pasture syndrome, have been reported to be associated to the treatment. In the present report, we present three CLL patients developing acute inflammatory demyelinating neuropathy during treatment with alemtuzumab. Despite the severity of the complication, all the patients showed an univocal good clinical response after treatment with intravenous immunoglobulin (IVIG). As alemtuzumab represents, nowadays, a key therapeutic option for CLL, clinicians should be aware of this rare and disabling toxicity.

Analytic Review: Neurological Complications of Transplantation

Recipients of solid organ or hematopoietic cell transplants are at risk of life-threatening neurological disorders including encephalopathy, seizures, infections and tumors of the central nervous system, stroke, central pontine myelinolysis, and neuromuscular disorders—often requiring admission to, or occurring in, the intensive care unit (ICU). Many of these complications are linked directly or indirectly to immunosuppressive therapy. However, neurological disorders may also result from graft versus host disease, or be an expression of the underlying disease which prompted transplantation, as well as injury induced during radiation, chemotherapy, surgery, and ICU stay. In rare cases, neuroinfectious pathogens may be transmitted with the transplanted tissue or organ. Diagnosis may be a challenge because clinical symptoms and findings on neuroimaging lack specificity, and a biological specimen or tissue diagnosis is often needed for definitive diagnosis. Management is centered on preventing further neurological injury, etiology-targeted therapy, and balancing the benefits and toxicities of specific immunosuppressive agents.

Hematopoietic stem cell transplantation for hemoglobinopathies: current practice and emerging trends

Despite improvements in the management of thalassemia major and sickle cell disease, treatment complications are frequent and life expectancy remains diminished for these patients. Hematopoietic stem cell transplantation (HSCT) is the only curative option currently available. Existing results for HSCT in patients with hemoglobinopathy are excellent and still improving. New conditioning regimens are being used to reduce treatment-related toxicity and new donor pools accessed to increase the number of patients who can undergo HSCT.

From bench to bedside--experimental rationale for immune-specific therapies in the inflamed peripheral nerve

Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy are autoimmune-mediated inflammatory diseases of the PNS. In recent years, substantial progress has been made towards understanding the immune mechanisms that underlie these conditions, in large part through the study of experimental models. Here, we review the available animal models that partially mimic human Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy, and discuss the wide range of therapeutic approaches that have been successfully established in these models of inflammatory neuropathies. Transfer of this preclinical knowledge to patients has been far less successful, and inflammatory neuropathies are still associated with significant morbidity and mortality. We will summarize successful therapeutic trials in human autoimmune neuropathies to provide a vantage point for the transfer of experimental treatment strategies to clinical practice in immune-mediated diseases of the peripheral nerve.

Hematopoietic cell transplantation for sickle cell disease: state of the art

Sickle cell disease is associated with considerable morbidity and premature mortality. Hematopoietic cell transplantation offers the possibility of cure and is associated with excellent results in pediatric patients receiving stem cell transplantation from a matched sibling donor. A reduced-intensity conditioning regimen has the potential to further reduce regimen-related morbidity and mortality. Improved understanding of the natural history of complications, such as stroke and pulmonary hypertension, effects of treatments such as hydroxyurea and blood transfusions, as well as the impact of transplantation on organ damage, are likely to influence the timing and indication of transplantation. Improvements in preparative regimens may enable the safe use of an alternative source of stem cells, such as unrelated matched donors, and further improve the applicability and acceptability of this treatment.

Exogenous administration of immunomodulatory therapies in hematopoietic cell transplantation: an infectious diseases perspective

PURPOSE OF REVIEW

In contrast to the recipient of a solid organ transplantation, the immunological competence of recipients of hematopoietic cell transplantation does not correlate well with the administration of non-corticosteroid immunosuppressive agents. This apparent paradox reflects the unique and dynamic conglomeration of factors that affect immune reconstitution after hematopoietic cell transplantation. The following is the second part of a review of the recent primary literature regarding exogenous immunomodulatory influences as they pertain to infections in the setting of hematopoietic cell transplantation.

RECENT FINDINGS

The main themes of published primary research from 2004 to the present include the influence of exogenously administered immunomodulatory agents on infectious complications after hematopoietic cell transplantation.

SUMMARY

The use of immunomodulatory agents such as monoclonal antibodies directed against lymphocyte antigens in the treatment of hematopoietic malignancy has greatly expanded during the past decade. Separate trials of the potential utility of these agents, particularly in the reduction of graft-versus-host disease, in the setting of hematopoietic cell transplantation have yielded encouraging results. Given the infancy of these new approaches, it is not possible to make definitive statements regarding the relative risk of serious infection with each therapy. It is clear that a reduction in regimen-related non-infectious complications or mortality does not necessarily ensure a reduction in clinically significant infections. Improvements in early diagnostic and therapeutic options for these infections now bring us to an era of understanding pathogens such as cytomegalovirus as probes of the functional reconstitution of immunity.