Rituximab used successfully in the treatment of anti-NMDA receptor encephalitis

Efficacy and Safety of Rituximab in Chinese Children With Refractory Anti-NMDAR Encephalitis

Purpose: To assess the efficacy and safety of rituximab treatment as second-line immunotherapy in pediatric cases of anti-NMDA receptor (NMDAR) encephalitis. Methods: We retrospectively recruited 8 patients with anti-NMDAR encephalitis who were treated with rituximab as second-line immunotherapy. We evaluated the clinical features, laboratory examination results and treatment protocols of the Chinese children and defined good outcomes based on the modified Rankin scale (mRS) score (0-2) at the last follow-up. Results: A total of eight pediatric patients (median age 6.7 years; four female) with refractory anti-NMDAR encephalitis were recruited to the study. Rituximab was given after a median duration of disease of 57 days (range 50.5-113.75 days). The use of rituximab led to a significant reduction in the mRS and CD19+ B-cells compared to before rituximab infusion (P < 0.05). Five patients (62.5%) had a good outcome (mRS ≤ 2) including four patients (50%) who showed complete recovery (mRS = 0) at the last follow-up. Transient infusion adverse events were recorded in 2 patients (25%). Two patients (25%) had severe infectious adverse events (AEs) and two patients with grade 5 (death). None of the patients developed progressive multifocal leukoencephalopathy (PML). Conclusion: Our study provides evidence that rituximab can efficiently improve the clinical symptoms of anti-NMDAR encephalitis in children. However, due to the risk of adverse infections, rituximab should be restricted in pediatric patients with high rates of mortality and disability.

Levofloxacin-associated Encephalopathy with Severe Hyperventilation

A 64-year-old woman with no previous mental illness took a single 500 mg tablet of levofloxacin for cystitis. Two hours later, she developed psychosis with involuntary movement and severe hyperventilation with respiratory alkalosis. Cranial magnetic resonance imaging findings were unremarkable, and an electroencephalogram revealed no epileptiform discharge. Her symptoms improved on the third day after levofloxacin was discontinued. Levofloxacin-associated encephalopathy with psychotic features is a rare adverse event. Disturbance of gamma-aminobutyric acid-ergic (GABAergic) interneurons by levofloxacin may lead to hyperventilation via dysfunction of the brainstem respiratory network. Physicians should be aware of hyperventilation as an additional serious symptom of levofloxacin-associated encephalopathy in acute settings.

Successful treatment of anti-NMDA receptor encephalitis with early teratoma removal and plasmapheresis: A case report

RATIONALE

This report describes a Successful treatment of anti-NMDA receptor encephalitis with early teratoma removal and plasmapheresis.

PATIENT CONCERNS

We present a 31-year-old Caucasian nulliparous patient who was admitted as an emergency with general illness status accompanied by holocranial cephalalgia and fever.

DIAGNOSES

The previous symptoms were followed by disorientation, persecutory delusion, incoherent language, and tonic-clonic seizure.

INTERVENTIONS

The patient was admitted in the intensive care unit (ICU) with Glasgow score 7.

OUTCOMES

Most of complementary exams (brain CT, brain MRI, blood analysis, PCR for virus on CSF) were normal except CSF leucocytosis and hyperproteinorrhachia. An abdominopelvic ultrasound revealed a 5-cm solid-cystic tumor in the left adnexal region, suggestive of teratoma. At that stage, the possibility of autoimmune encephalitis was considered, and confirmed later.

LESSONS

This disease can only be successfully treated with fast surgical intervention and an early implementation of immunosuppressive therapies. The optimal timing of initiation and duration of therapeutic plasma exchange necessary to achieve good outcomes in patients with NMDAR remains unknown. This case report intends to increase awareness about the importance of early surgical treatment and early implementation of this potentially life-saving therapy and of continuing the treatment until complete remission of symptoms.

Anti-NMDA Receptor Encephalitis: Clinical Features and Basic Mechanisms

In slightly more than 10 years, anti-NMDA receptor (NMDAR) encephalitis has changed from a rare paraneoplastic syndrome to the most common cause of nonviral encephalitis. It presents fulminantly with progressive psychosis, seizures, and autonomic dysfunction, leading to death if untreated. However, rapid recognition and treatment can lead to survival and a return to baseline levels of functioning in many patients. While initially associated with ovarian teratomas, it is now associated with other tumors and can reflect a postviral event. The antibodies to the NMDAR made in this syndrome are pathogenic and are directed at the extracellular domain of the GluN1 subunit. Such antibodies lead to internalization of NMDARs in model systems, leading to a physiological state characterized by NMDAR hypofunction. Analogous disorders, characterized by antibodies to other synaptic receptors, present with neurological and psychiatric dysfunction and also appear to reflect antibody-induced internalization of receptors. However, this simple pathophysiology may be too simplistic to reflect the complexity of events in anti-NMDAR encephalitis. Future scientific investigations may allow a more complete understanding of this disorder and improve treatment of anti-NMDAR encephalitis.

Lower dosages of rituximab used successfully in the treatment of anti-NMDA receptor encephalitis without tumour

OBJECTIVE

The aim of this study was to evaluate the use and efficacy of lower dosages of rituximab for treating anti N-methyl-d-aspartate receptor (NMDAR) encephalitis without tumour.

METHODS

We performed a prospective study of 10 patients with anti-NMDAR encephalitis who did not respond to 10 to 14days first-line immunotherapy and received rituximab administered intravenously (IV) at a dosage of 100mg once per week for 4 consecutive weeks. Reinfusion of rituximab was given when CD19⁺ B-cell counts of total lymphocytes in peripheral blood >1%. The annualized relapse rate (ARR), modified Rankin scale (mRS) and CD19⁺ B-cell counts were measured every 4 to 10weeks after initial rituximab treatment in order to assess the clinical outcome and efficacy of rituximab.

RESULTS

Lower dosages of rituximab led to a significant reduction of mRS and CD19⁺ B-cells when compared with before the rituximab infusion (P<0.05) and allowed 9 (90%) patients to maintain a stabilised neurological status. One patient experienced a relapse at 19weeks after initial rituximab infusion. Although ARR reduction of all 10 patients did not achieve statistical significance (P>0.05), in the 4 patients who had relapses before rituximab treatment there was an apparent reduction in ARR over 56weeks. At the last follow up, 9 patients (90%) had a good outcome (mRS≤2) including 3 patients (30%) who recovered completely (mRS=0). Transient infusion adverse events occurred in 2 patients. We observed no serious delayed adverse events during the 56weeks follow-up.

CONCLUSIONS

In patients with anti-NMDAR encephalitis who did not respond to first-line immunotherapy, early application of lower dosages of rituximab could efficiently reduce CD19⁺ B-cell counts of peripheral blood and improve the prognosis of anti-NMDAR encephalitis.

Successful treatment of anti-NMDA receptor encephalitis with a prompt ovarian tumour removal and prolonged course of plasmapheresis: A case report

Anti-N-methyl-d-aspartate-receptor (NMDAR) encephalitis is an uncommon autoimmune disorder with a wide spectrum of neuropsychiatric symptoms. There is a great requirement to emphasize the importance of a multidisciplinary team approach in the process of diagnosis and treatment of the potentially fatal condition, including psychiatrists, neurologists, gynaecologists and intensivists. Physicians must be aware that psychiatric and neurological disorders, which are typical features for NMDAR encephalitis in young women with ovarian tumours, may progress into status epilepticus and respiratory insufficiency. This disease can only be successfully treated with prompt surgical intervention and an early implementation of a wide array of immunosuppressive therapies. Optimal timing of initiation of therapeutic plasma exchange, as well as duration of treatment necessary to achieve desirable outcomes in patients with NMDAR remains unknown. The present case report aims to raise awareness about the importance of early implementation of this potentially life-saving therapy and continuing the treatment courses until full subsidence of symptoms.

Extra-central nervous system target for assessment and treatment in refractory anti-N-methyl-d-aspartate receptor encephalitis

Anti-N-methyl-d-aspartate-type glutamate receptor autoimmune encephalitis can arise in the setting of ovarian teratoma and often responds to resection. When it occurs in the absence of tumor, failure to respond to treatment may be more likely, and affected patients often require intensive care. To further understand the mechanisms and potential management, we present findings from an autopsy conducted on a young woman who died of refractory autoimmune encephalitis of this type. Rituximab was administered 70 days before death, and both 37 and 14 days before death, CD19⁺ lymphocytes were only 0.1% of blood cells. Ten sessions of plasmapheresis were performed after rituximab treatment. Nonetheless, the autoantibodies were present in serum 4 days before death, demonstrating ongoing antibody production. The hippocampus and medial temporal lobe demonstrated inflammation with T cell and prominent microglial involvement, but no plasma cells or plasmablasts were found there, or anywhere in the brain, despite an extensive search. Examination of lymph node tissue identified many plasma cells along sinusoids. These findings demonstrate that the antibody-producing cells are long-lived and can reside in lymphoid tissue. Awareness of continuing antibody production, the extra-central nervous system site, the indication for cytotoxic therapy, and the potential for biopsy assessment may lead to more effective treatment.

Anti N-methyl-D-aspartate receptor encephalitis: a game-changer?

INTRODUCTION

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an inflammatory disorder of the brain that has garnered significant interest within the medical and lay communities. There is a need for formal guidelines to assist physicians in identifying patients who should undergo testing for NMDAR encephalitis, recognizing the high potential for this potentially treatable disease to mimic more common disorders, and consequently remain undiagnosed.

AREAS COVERED

This review highlights the impact of the discovery of NMDAR encephalitis on the fields of neurology and psychiatry, and discusses the steps that are necessary to improve recognition and treatment of NMDAR encephalitis. Expert commentary: While much progress has been made in our understanding of NMDAR encephalitis, much work remains to be done to delineate the underlying disease mechanisms and their relevance to brain function.

A case of anti-NMDAR encephalitis presented hypotensive shock during plasma exchange

We are reporting on a case of pediatric anti-NMDAR encephalitis with autonomic instability. The patient showed little response to first-line treatment of steroid and IVIG. We initiated plasma exchange, also a first-line treatment. This worsened his autonomic instability, resulting in hypotensive shock. He responded well to rituximab and cyclophosphamide, second-line therapies. Anti-NMDAR encephalitis is often accompanied by autonomic instability. Our and other reported cases, raise the question of plasma exchange as a first-line therapy for pediatric NMDAR encephalitis, which is frequently accompanied by autonomic instability. Plasma exchange should be performed cautiously in such patients.

Autoimmune channelopathies in paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes and autoimmune encephalitides are immune neurological disorders occurring or not in association with a cancer. They are thought to be due to an autoimmune reaction against neuronal antigens ectopically expressed by the underlying tumour or by cross-reaction with an unknown infectious agent. In some instances, paraneoplastic neurological syndromes and autoimmune encephalitides are related to an antibody-induced dysfunction of ion channels, a situation that can be labelled as autoimmune channelopathies. Such functional alterations of ion channels are caused by the specific fixation of an autoantibody upon its target, implying that autoimmune channelopathies are usually highly responsive to immuno-modulatory treatments. Over the recent years, numerous autoantibodies corresponding to various neurological syndromes have been discovered and their mechanisms of action partially deciphered. Autoantibodies in neurological autoimmune channelopathies may target either directly ion channels or proteins associated to ion channels and induce channel dysfunction by various mechanisms generally leading to the reduction of synaptic expression of the considered channel. The discovery of those mechanisms of action has provided insights on the regulation of the synaptic expression of the altered channels as well as the putative roles of some of their functional subdomains. Interestingly, patients' autoantibodies themselves can be used as specific tools in order to study the functions of ion channels. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

Refractory status epilepticus caused by anti-NMDA receptor encephalitis that markedly improved following combination therapy with rituximab and cyclophosphamide

We herein describe the case of a 48-year-old woman who presented with nonconvulsive status epilepticus refractory to antiepileptic drugs caused by anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis without any tumors. She developed nausea and psychiatric symptoms, followed by fever and an acute progressive disturbance of consciousness. On admission to our hospital, she presented with involuntary orofacial movements and central hypoventilation, and an electroencephalogram showed a generalized slow activity consistent with nonconvulsive status epilepticus. The patient's drug-resistant status epilepticus markedly improved following second-line immunotherapy with rituximab and cyclophosphamide. Physicians should consider the early initiation of second-line therapy in certain cases of anti-NMDAR encephalitis.

Three phenotypes of anti-N-methyl-D-aspartate receptor antibody encephalitis in children: prevalence of symptoms and prognosis

BACKGROUND

Anti-N-methyl-d-aspartate (NMDA) receptor antibody encephalitis is becoming an increasingly recognized cause of encephalopathy in individuals previously presumed to have viral encephalitis. Various manifestations of this disease include altered mental status, behavioral changes, seizures, and movement disorders. We have noted three distinct subtypes of this disease which appear to have differential responses to immunotherapies and differences in prognosis.

METHODS AND PATIENTS

We report eight patients observed at our children's hospital from 2009 through 2013 who appear to clearly fall into one of our three clinical categories. To find comparable articles reflecting this classification, we then performed a MEDLINE search of all articles involving the subject heading "anti-NMDA receptor encephalitis" or just the keyword phrase "NMDA encephalitis," and we found 162 articles to review. Twenty-two articles were eliminated due to basic science, and we were able to review 105 of the remaining articles, most of which were case reports or case series, although a few were larger reviews. For the sake of our review, we defined type 1 or "classic" anti-NMDA receptor antibody encephalitis as having a duration of <60 days and being characterized predominantly by a catatonic or stuporous state, type 2 or psychiatric-predominant anti-NMDA receptor antibody encephalitis as having no noteworthy catatonic or stuporous state in addition to the presence of predominantly behavioral and psychiatric symptoms, and type 3 or catatonia-predominant anti-NMDA receptor antibody encephalitis as having a duration of ≥60 days in a predominantly catatonic or stuporous state.

RESULTS

We note that the poorest responders, even to aggressive immunotherapies, are the patients with catatonia-persistent type anti-NMDA receptor antibody encephalitis, which has, as its hallmark, prolonged periods of severe encephalopathy. Patients with predominantly psychiatric symptoms, which we call the psychiatric-predominant anti-NMDA receptor antibody encephalitis, have had excellent responses to plasma exchange or other immunotherapies and appear to have the least residual deficits at follow-up. Patients with fairly equal representations of periods of altered mental status, behavioral problems, and movement disorders appear to have an intermediate prognosis and likely require early aggressive immunotherapy.

CONCLUSIONS

In our series, we discuss representative examples of these clinical subtypes and their associated outcomes, and we suggest that tracking these subtypes in future cases of anti-NMDA receptor antibody encephalitis might lead to better understanding and better risk stratification with regard to immunotherapy decisions.

Anti-NMDAR autoimmune encephalitis

The N-methyl-D-aspartate receptor (NMDAR) is involved in normal physiological and pathological states in the brain. Anti-NMDAR encephalitis is characterized by memory deficits, seizures, confusion, and psychological disturbances in males and females of all ages. This type of encephalitis is often associated with ovarian teratoma in young women, but children are less likely to have tumors. Anti-NMDAR encephalitis is a neuroimmune syndrome in patients with autoantibodies recognizing extracellular epitopes of NMDAR, and the autoantibodies attenuate NMDAR function through the internalization of NMDAR. Following the initial symptoms of inflammation, the patients show the various symptoms such as memory loss, confusion, emotional disturbances, psychosis, dyskinesis, decrease in speech intelligibility, and seizures. About half of these patients improved with immunotherapy including high-dose intravenous corticosteroids and intravenous immunoglobulins is administrated to these patients, but the patients who had no improvement with these therapy require further treatments with rituximab or cyclophosphamide. It is necessary to detect anti-NMDAR antibodies at early stages, because the prognosis of these patients may be improved by early treatment. Recovery is slow, and the patients may have some disturbances in their motor function and cognition. The pathologic mechanism underlying the development of anti-NMDAR encephalitis has been elucidated gradually, but the optimal treatment has not yet been clarified. Further studies are required to clarify in detail the mechanism underlying anti-NMDA encephalitis and to develop effective treatments.

Autoimmune profiling with protein microarrays in clinical applications

In recent years, knowledge about immune-related disorders has substantially increased, especially in the field of central nervous system (CNS) disorders. Recent innovations in protein-related microarray technology have enabled the analysis of interactions between numerous samples and up to 20,000 targets. Antibodies directed against ion channels, receptors and other synaptic proteins have been identified, and their causative roles in different disorders have been identified. Knowledge about immunological disorders is likely to expand further as more antibody targets are discovered. Therefore, protein microarrays may become an established tool for routine diagnostic procedures in the future. The identification of relevant target proteins requires the development of new strategies to handle and process vast quantities of data so that these data can be evaluated and correlated with relevant clinical issues, such as disease progression, clinical manifestations and prognostic factors. This review will mainly focus on new protein array technologies, which allow the processing of a large number of samples, and their various applications with a deeper insight into their potential use as diagnostic tools in neurodegenerative diseases and other diseases. This article is part of a Special Issue entitled: Biomarkers: A Proteomic Challenge.