Anti-N-Methyl- d -Aspartate receptor (NMDAR) encephalitis during pregnancy: Clinical analysis of reported cases

Pregnancy and antibody-mediated CNS disorders: What do we know and what should we know?

Antibody-mediated central nervous system (CNS) disorders including those associated with aquaporin-4 or myelin oligodendrocyte glycoprotein IgG and autoimmune encephalitis often affect women of childbearing age. Pathogenic antibodies of these diseases can potentially alter reproductive functions and influence fetal development. Hormonal changes occurring during pregnancy may modify the course of autoimmune diseases by influencing relapse risk, attack severity, and affect the delivery and postpartum period. Moreover, balancing treatment related safety issues with the risk of potentially disabling relapses during pregnancy and breastfeeding are major challenges. Intentional prenatal, gestational, and post-partum counseling is paramount to address these issues and mitigate these risks. Fortunately, new insights on risk factors for adverse pregnancy outcomes and possible preventive strategies are emerging. This review aims to summarize the interplay between antibody-mediated CNS disorders and pregnancy during the prenatal, gestational, and postpartum periods, highlight current treatment recommendations, and discuss future areas of research.

Psychiatric manifestations of autoimmune encephalitis

Autoimmune encephalitis is increasingly recognized as a cause of psychiatric symptoms. A wide spectrum of psychiatric manifestations have been described which may precede, follow or occur independently of neurologic features. Patients typically respond to immunotherapy, however diagnosis is challenging due to phenotypic heterogeneity. The aim of this review is to provide an overview of the psychiatric features associated with encephalitis mediated by autoantibodies targeting neuronal cell-surface antigens and describe indicators of potential immunopathology underlying psychiatric manifestations.

Impairment of early neuronal maturation in anti-NMDA-receptor encephalitis

RATIONALE

Adequate immunotherapies for anti-NMDAR encephalitis during pregnancy produce a relatively good clinical outcome for pregnant mothers and their infants, but there are no reports about the future growth of their babies. The damage of anti-NMDAR antibodies to early neuronal development is still unknown.

OBJECTIVES

Serum or cerebrospinal fluid from one patient with anti-NMDAR encephalitis (the index patient) and one patient with schizophrenia (the control patient) was administered to primary cultures of dissociated rat cortical neurons, and dendritic outgrowth, centrosome elimination, and branching of dendrites were investigated. For rescue experiments, serum of the index patient was replaced with normal culture media after 3 days' administration of the index patient.

RESULTS

Serum and cerebrospinal fluid of the index patient statistically significantly impaired dendritic outgrowth of cultured rat cortical primary neurons. Serum of the index patient also statistically significantly delayed centrosome elimination. Impaired dendritic outgrowth and delayed centrosome elimination were not perfectly rescued by changing to normal culture media. Serum of the index patient also statistically significantly reduced the branching of dendrites.

CONCLUSIONS

This is the first demonstration of the damage by anti-NMDAR antibodies on early dendritic development in vitro. As a strategy to protect embryonic neurons, our findings may support the efficacy of early immunotherapy for anti-NMDAR encephalitis in pregnancy.

Research progress in teratoma-associated anti-N-methyl-D-aspartate receptor encephalitis: The gynecological perspective

AIM

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the autoimmune encephalitis, which often occurs in children and young adults, especially in young women. In addition to viral infection, teratoma is an important causative factor. Anti-NMDAR encephalitis is well known to neurologist. However, this is less well known to gynecologists, who may have a decisive role in etiological management. Therefore, from the perspective of gynecologists, we provide an overview of the relationship between the encephalitis and ovarian teratoma, the clinical features and treatment of this disease, and prognosis of pregnant women with this encephalitis.

METHODS

We searched the PubMed database using the search terms in various combinations "teratoma," "dermoid cyst," "ovary," "ovarian," "anti-NMDAR encephalitis," and "N-methyl-D-aspartate receptor."

RESULTS

According to the current literature, the mechanism of anti-NMDAR encephalitis is probably due to the ectopic expression of the NMDAR in the teratomas tissue. The disease has a high mortality rate if not treated promptly and effectively. An important way to improve patients' outcome is to remove the ovarian tumor in time. Pregnant women are also at risk of developing anti-NMDAR encephalitis during pregnancy. The fetal outcome is usually better in patients with mid- to late-pregnancy onset than in early pregnancy, and patients are often able to maintain their pregnancies into late pregnancy.

CONCLUSION

Young women with sudden onset of abnormal psychiatric behavior should be actively screened for ovarian tumors and, if confirmed to be teratoma-associated anti-NMDAR encephalitis, should undergo gynecologic surgery as early as possible, which can help improve their prognosis.

Anti-N-Methyl-D-Aspartate Receptor Encephalitis with Serum Anti-Thyroid Antibodies: A Case Report and Literature Review

BACKGROUND Anti-N methyl D-aspartate receptor encephalitis (anti-NMDArE) is a disorder in which triggers such as infectious agents or neoplastic disease can lead to an autoimmune response against the nervous system, although this disorder is usually idiopathic. Some patients with anti-NMDArE have evidence of other autoimmune alterations. Here, we present a case of non-paraneoplastic anti-NMDArE with elevation of serum anti-thyroid antibodies and a literature review of this association. CASE REPORT A 16-year-old girl was admitted in the University Hospital of Bari for a new onset of tonic-clonic seizures. Progressively, the patient manifested also psychomotor agitation, language difficulties, memory impairment, psychotic symptoms, autonomic dysfunction, and psychomotor retardation. Blood evaluation revealed the presence of anti-thyroglobulin, anti-thyroperoxidase, and anti-NMDAr antibodies. Cerebrospinal fluid analysis confirmed the diagnosis of anti-NMDArE. No tumors were found. Treatment with intravenous immunoglobulin, steroids, and plasma exchange relieved symptoms and decreased levels of serum anti-NMDAr antibodies. After 12 months, the patient had full recovery of communicative capacity, with the persistence of slight difficulty of memory and mild tendency to irritability. Blood exams shown persistence of anti-NMDAr positivity and absence of anti-thyroid antibodies. CONCLUSIONS We report a rare case in which an autoimmune involvement of thyroid gland was concurrent with an anti-NMDArE. It would be useful for clinical practice to clarify whether the presence of anti-thyroid antibody an characterize the clinical course, prognosis, and response to treatment of the idiopathic type of anti-NMDArE.

Autoimmune Disorders of the Nervous System: Pathophysiology, Clinical Features, and Therapy

Remarkable discoveries over the last two decades have elucidated the autoimmune basis of several, previously poorly understood, neurological disorders. Autoimmune disorders of the nervous system may affect any part of the nervous system, including the brain and spinal cord (central nervous system, CNS) and also the peripheral nerves, neuromuscular junction and skeletal muscle (peripheral nervous system, PNS). This comprehensive overview of this rapidly evolving field presents the factors which may trigger breakdown of self-tolerance and development of autoimmune disease in some individuals. Then the pathophysiological basis and clinical features of autoimmune diseases of the nervous system are outlined, with an emphasis on the features which are important to recognize for accurate clinical diagnosis. Finally the latest therapies for autoimmune CNS and PNS disorders and their mechanisms of action and the most promising research avenues for targeted immunotherapy are discussed.

Anti-N-methyl-d-aspartate Receptor Encephalitis Related Sinus Node Dysfunction and the Lock-Step Phenomenon

Described in 2007, anti-N-methyl-d-aspartate receptor encephalitis (ANMDARE) is a rare autoimmune limbic encephalitis affecting young adults (predominantly women of reproductive age) and is a paraneoplastic manifestation of ovarian teratoma in about half of the cases. ANMDARE is characterized by psychiatric changes, neurological changes, autonomic instability and cardiac dysrhythmias. In this report, we present a 36-year-old woman who was 16 weeks pregnant and brought to the hospital with confusion and subsequently had a seizure with Electroencephalography (EEG) demonstrated an extreme delta brush pattern consistent with ANMDARE. Patient developed sinus nodal dysfunction and was also found to have ovarian teratoma, a rather typical presentation for ANMDARE, that is considered a paraneoplastic syndrome for ovarian teratoma. In this report, we highlight the cardiac manifestation of ANMDARE, the pathophysiology associated with autonomic instability, and management strategies of this rare, and largely devastating illness.

Maternal-Autoantibody-Related (MAR) Autism: Identifying Neuronal Antigens and Approaching Prospects for Intervention

Recent studies indicate the existence of a maternal-autoantibody-related subtype of autism spectrum disorder (ASD). To date, a large number of studies have focused on describing patterns of brain-reactive serum antibodies in maternal-autoantibody-related (MAR) autism and some have described attempts to define the antigenic targets. This article describes evidence on MAR autism and the various autoantibodies that have been implicated. Among other possibilities, antibodies to neuronal surface protein Contactin Associated Protein 2 (CASPR2) have been found more frequently in mothers of children with neurodevelopmental disorders or autism, and two independent experimental studies have shown pathogenicity in mice. The N-methyl-D-aspartate receptor (NMDAR) is another possible target for maternal antibodies as demonstrated in mice. Here, we discuss the growing evidence, discuss issues regarding biomarker definition, and summarise the therapeutic approaches that might be used to reduce or prevent the transfer of pathogenic maternal antibodies.

In vivo Mechanisms of Antibody-Mediated Neurological Disorders: Animal Models and Potential Implications

Over the last two decades, the discovery of antibodies directed against neuronal surface antigens (NSA-Abs) in patients with different forms of encephalitis has provided a basis for immunotherapies in previously undefined disorders. Nevertheless, despite the circumstantial clinical evidence of the pathogenic role of these antibodies in classical autoimmune encephalitis, specific criteria need to be applied in order to establish the autoimmune nature of a disease. A growing number of studies have begun to provide proof of the pathogenicity of NSA-Abs and insights into their pathogenic mechanisms through passive transfer or, more rarely, through active immunization animal models. Moreover, the increasing evidence that NSA-Abs in the maternal circulation can reach the fetal brain parenchyma during gestation, causing long-term effects, has led to models of antibody-induced neurodevelopmental disorders. This review summarizes different methodological approaches and the results of the animal models of N-methyl-d-aspartate receptor (NMDAR), leucine-rich glioma-inactivated 1 (LGI1), contactin-associated protein 2 (CASPR2), and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) antibody-mediated disorders and discuss the results and the limitations. We also summarize recent experiments that demonstrate that maternal antibodies to NMDAR and CASPR2 can alter development in the offspring with potential lifelong susceptibility to neurological or psychiatric disorders.

Neuroimmunologic disorders in pregnancy

Pregnancy influences the course of neuroimmunologic conditions, which include multiple sclerosis (MS), neuromyelitis optica spectrum disorder, and autoimmune encephalitis. The outcomes differ significantly for each disorder, reflecting the impact of hormonal changes, T-cell subsets, and placental factors on disease pathogenesis. In recent years, numerous data have emerged regarding MS activity throughout pregnancy and postpartum. Historically, the misconception that pregnancy worsens MS outcomes led patients to abstain from childbearing. Now, more women with these disorders, empowered by up-to-date information and better baseline disease control, are choosing to conceive. Nevertheless, the management of MS and related disorders in the pregnancy and postpartum period is complicated and requires a nuanced approach. Since standardized treatment guidelines around pregnancy are currently lacking, neurologists, together with obstetricians, must engage patients in a shared decision-making process that weighs the benefits to the mother and risks to the fetus. This chapter outlines the pathophysiology of neuroimmunologic disorders during pregnancy and postpartum, the impact of these diseases on childbearing, including fertility, pregnancy, delivery, and peurperium, as well as existing recommendations for treatment.

Anti-N-methyl-D-aspartate receptor encephalitis: A review of pathogenic mechanisms, treatment, prognosis

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a treatable autoimmune disorder characterized by prominent neuropsychiatric symptoms that predominantly affects children and young adults. In this review, we discuss the pathogenic mechanisms and immunologic triggers of anti-NMDAR encephalitis, and provide an overview of treatment and prognosis of this disorder, with specific focus on the management of common symptoms, complications, and patients during pregnancy. Most patients respond well to first-line treatment and surgical resection of tumors. When first-line immunotherapy fails, second-line immunotherapy can often improve outcomes. In addition, treatment with immunomodulators and tumor resection are effective treatment strategies for pregnant patients. Benzodiazepines are the preferred treatment for patients with catatonia, and electroconvulsive therapy (ECT) may be considered when pharmacological treatment is ineffective. Age, antibody titer, cerebellar atrophy, levels of biomarkers such as C-X-C motif chemokine 13 (CXCL13), cell-free mitochondrial (mt)DNA in cerebral serum fluid (CSF), and timing from symptom onset to treatment are the main prognostic factors. Patients without tumors or those who receive insufficient immunotherapy during the first episode are more likely to relapse.

Human gestational N-methyl-d-aspartate receptor autoantibodies impair neonatal murine brain function

OBJECTIVE

Maternal autoantibodies are a risk factor for impaired brain development in offspring. Antibodies (ABs) against the NR1 (GluN1) subunit of the N-methyl-d-aspartate receptor (NMDAR) are among the most frequently diagnosed anti-neuronal surface ABs, yet little is known about effects on fetal development during pregnancy.

METHODS

We established a murine model of in utero exposure to human recombinant NR1 and isotype-matched nonreactive control ABs. Pregnant C57BL/6J mice were intraperitoneally injected on embryonic days 13 and 17 each with 240μg of human monoclonal ABs. Offspring were investigated for acute and chronic effects on NMDAR function, brain development, and behavior.

RESULTS

Transferred NR1 ABs enriched in the fetus and bound to synaptic structures in the fetal brain. Density of NMDAR was considerably reduced (up to -49.2%) and electrophysiological properties were altered, reflected by decreased amplitudes of spontaneous excitatory postsynaptic currents in young neonates (-34.4%). NR1 AB-treated animals displayed increased early postnatal mortality (+27.2%), impaired neurodevelopmental reflexes, altered blood pH, and reduced bodyweight. During adolescence and adulthood, animals showed hyperactivity (+27.8% median activity over 14 days), lower anxiety, and impaired sensorimotor gating. NR1 ABs caused long-lasting neuropathological effects also in aged mice (10 months), such as reduced volumes of cerebellum, midbrain, and brainstem.

INTERPRETATION

The data collectively support a model in which asymptomatic mothers can harbor low-level pathogenic human NR1 ABs that are diaplacentally transferred, causing neurotoxic effects on neonatal development. Thus, AB-mediated network changes may represent a potentially treatable neurodevelopmental congenital brain disorder contributing to lifelong neuropsychiatric morbidity in affected children. ANN NEUROL 2019;86:656-670.

An update on anti-NMDA receptor encephalitis for neurologists and psychiatrists: mechanisms and models

The identification of anti-NMDA receptor (NMDAR) encephalitis about 12 years ago made it possible to recognise that some patients with rapidly progressive psychiatric symptoms or cognitive impairment, seizures, abnormal movements, or coma of unknown cause, had an autoimmune disease. In this disease, autoantibodies serve as a diagnostic marker and alter NMDAR-related synaptic transmission. At symptom onset, distinguishing the disease from a primary psychiatric disorder is challenging. The severity of symptoms often requires intensive care. Other than clinical assessment, no specific prognostic biomarkers exist. The disease is more prevalent in women (with a female to male ratio of around 8:2) and about 37% of patients are younger than 18 years at presentation of the disease. Tumours, usually ovarian teratoma, and herpes simplex encephalitis are known triggers of NMDAR autoimmunity. About 80% of patients improve with immunotherapy and, if needed, tumour removal, but the recovery is slow. Animal models have started to reveal the complexity of the underlying pathogenic mechanisms and will lead to novel treatments beyond immunotherapy. Future studies should aim at identifying prognostic biomarkers and treatments that accelerate recovery.