Screening Autoimmune Anti-neuronal Antibodies in Pediatric Patients with Suspected Autoimmune Encephalitis

Clinical characteristics and long-term outcome of CASPR2 antibody-associated autoimmune encephalitis in children

BACKGROUND

Contactin-associated protein-2(CASPR2) antibody-associated autoimmune encephalitis(AE) is rare in children. This study aimed to report the clinical characteristics and long-term outcome of CASPR2 autoimmunity in children to expand the disease spectrum.

METHODS

Children who were hospitalized in our hospital with clinically suspected AE from May 2015 to April 2022 and underwent neuronal surface antibodies detections were retrospectively analyzed. Clinical data of patients with CASPR2 autoimmunity were collected.

RESULTS

Patients who were positive for NMDAR-IgG, CASPR2-IgG, LGI1-IgG and IgLON5-IgG occupied 95.2%(119/125),3.2%(4/125),0.8%(1/125) and 0.8%(1/125), respectively.The median onset age of the 4 patients with CASPR2-IgG was 5.6 years. The most common symptoms were psychiatric symptoms/abnormal behavior(3/4) and sleep dysfunction(3/4). One patient developed a phenotype of Rasmussen encephalitis(RE). Tumor was absent in our patients. Two patients showed abnormal findings on initial brain magnetic resonance imaging(MRI) scans. All the patients showed favorable response to immunotherapy except the patient with RE experienced recurrent symptoms who finally achieved remission after surgery. All the patients had a favorable long-term outcome at the last follow-up(33-58months).

CONCLUSIONS

CASPR2 autoimmunity may be the second most common anti-neuronal surface antibodies associated neurological disease in children. Psychiatric symptoms/abnormal behavior and sleep disorder were common in children with CASPR2-associated AE. Tumor was rare in those patients. Most pediatric patients had a favorable long-term outcome.

Clinical outcome in an infant with anti-NMDA receptor encephalitis: case report and literature review

Anti N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disease that often presents with various neurological and neuropsychiatric symptoms. Although most reported cases occur in children, only a limited number of studies on children are available. The subject of this case report is an 8-month-old female who presented with fever, vomiting, and seizure. She was diagnosed with encephalitis and treated with acyclovir. After 21 days, she showed irritability, seizure, orolingual-facial dyskinesias, choreodystonic movements, hemiparesis, dysphagia, strabismus, lack of interest in light and objects. Clinical signs, neuroimaging findings, and serum analysis of anti-NMDAR antibodies confirmed the diagnosis of anti-NMDAR encephalitis. After the first line of treatment, she showed full recovery. We update the infants with anti-NMDAR encephalitis in the literature. Clinical outcomes suggest that patients with anti-NMDAR encephalitis are mostly poor in the infants, excluding our case. We propose that early and appropriate treatments are critical for timely diagnosis and rapid improvement.

Spatial and Ecological Factors Modulate the Incidence of Anti-NMDAR Encephalitis-A Systematic Review

Anti-NMDAR encephalitis has been associated with multiple antigenic triggers (i.e., ovarian teratomas, prodromal viral infections) but whether geographic, climatic, and environmental factors might influence disease risk has not been explored yet. We performed a systematic review and a meta-analysis of all published papers reporting the incidence of anti-NMDAR encephalitis in a definite country or region. We performed several multivariate spatial autocorrelation analyses to analyze the spatial variations in the incidence of anti-NMDA encephalitis depending on its geographical localization and temperature. Finally, we performed seasonal analyses in two original datasets from France and Greece and assessed the impact of temperature using an exposure-lag-response model in the French dataset. The reported incidence of anti-NMDAR encephalitis varied considerably among studies and countries, being higher in Oceania and South America (0.2 and 0.16 per 100,000 persons-year, respectively) compared to Europe and North America (0.06 per 100,000 persons-year) (p < 0.01). Different regression models confirmed a strong negative correlation with latitude (Pearson's R = -0.88, p < 0.00001), with higher incidence in southern hemisphere countries far from the equator. Seasonal analyses showed a peak of cases during warm months. Exposure-lag-response models confirmed a positive correlation between extreme hot temperatures and the incidence of anti-NMDAR encephalitis in France (p = 0.03). Temperature analyses showed a significant association with higher mean temperatures and positive correlation with higher ultraviolet exposure worldwide. This study provides the first evidence that geographic and climatic factors including latitude, mean annual temperature, and ultraviolet exposure, might modify disease risk.

Clinico-radiological characteristics of anti-myelin oligodendrocyte glycoprotein antibody-associated autoimmune encephalitis in children

AIM

To investigate the clinical characteristics and prevalence of paediatric anti-myelin oligodendrocyte glycoprotein (MOG) antibody-associated autoimmune encephalitis.

METHOD

A total of 94 paediatric patients (46 males, 48 females, median age 9 years 5 months, range: 8 months-17 years 8 months) with autoimmune encephalitis were recruited at Seoul National University Children's Hospital. We evaluated autoantibody status and identified patients with anti-MOG antibody-associated autoimmune encephalitis. Retrospective reviews of medical records were performed to describe clinical presentations, laboratory findings, treatments, and outcomes.

RESULTS

Eight patients (five males, three females, median age 11 years 9 months) with anti-MOG antibody-associated encephalitis were identified (8.5% of those with autoimmune encephalitis), one of whom was copositive for anti-N-methyl-d-aspartate receptor (NMDAR) antibodies. Anti-NMDAR antibodies were identified in 23 patients (23 out of 94, 24.5%). Unilateral or bilateral cortical involvement was identified in five patients. Focal contrast enhancement was also identified in three of the five patients with cortical lesions. All patients showed favourable response to immunotherapy with a Modified Rankin Scale ≤2 at the last follow-up. Relapse was found in one patient and clinico-radiological remission was achieved with cyclic intravenous immunoglobulin therapy.

INTERPRETATION

Anti-MOG antibody-associated encephalitis accounts for a significant proportion of clinically defined paediatric patients with autoimmune encephalitis. Anti-MOG antibody-associated encephalitis should be included in the clinical spectrum of anti-MOG-associated diseases.

Anti-contactin-associated protein-like 2 antibody-associated encephalitis in children: A case report and literature review

BACKGROUND

Anti-Contactin-associated protein-like 2 (CASPR2) antibody-associated encephalitis is a rare group of autoimmune diseases that causes extensive damage to the central and/or peripheral nervous system.

CASE PRESENTATION

Here, we reported a case of anti-CASPR2 antibody-associated encephalitis in a 12-year-old male patient with symptoms of headache, consciousness disturbance, mental abnormalities, urinary incontinence, fasciculations in the extremity muscles, and involuntary movements. The testing for autoimmune encephalitis-associated antibodies showed that CASPR2-associated antibodies were positive, and electroencephalography showed diffuse slow waves. No tumor was found after screening for malignancies. The child's status significantly improved after receiving immunotherapy with intravenous methylprednisolone and immunoglobulin.

CONCLUSIONS

Anti-CASPR2 antibody-associated encephalitis has been rarely reported in children. It has a complex clinical presentation and a low incidence of tumor. Most pediatric patients have a favorable prognosis and relapse is uncommon.

Speech, Language, and Communication Deficits and Intervention in a Single Case of Pediatric Autoimmune Encephalitis

Purpose The current literature on pediatric autoimmune encephalitis (AE) focuses on medical identification/diagnosis and medical treatments. Data about the identification and treatment of communication disorders in these children are limited. This clinical focus article provides an example of the speech, language, and communication characteristics, intervention, and recovery of a single child with medical diagnoses of pediatric AE and pediatric acute-onset neuropsychiatric syndrome (PANS) and special education eligibility under the autism spectrum disorder category. Method This is an in-depth illustrative/descriptive case study. Medical, educational, and speech-language documentation of one child diagnosed with AE at age 7 years was reviewed. Methods included interviews with family members, teachers, and the school speech-language pathologist and reviews of documentation including evaluations, reports, and Individualized Education Programs. Results This child received special education and therapy services through his public school and a university speech-language clinic. He concurrently received medical treatment for AE and PANS. Comprehensive augmentative and alternative communication (AAC) intervention included the use of core words, modeling, parallel talk, self-talk, expansive recasts, shared book reading, family counseling, and collaboration with the parents and the school speech-language pathologist. The child made progress on all goals despite irregular attendance to therapy due to medical complications. Discussion Because experimental research including this population is currently limited, this descriptive case study provides valuable information to clinicians, educators, pediatricians, medical diagnosticians, and anyone providing services to a child with a complex neuropsychological disorder like AE. Future research is needed with more children who have AE, especially experimental investigations of the intervention methods utilized here. Additional research of more children with AE can provide information about the scope and severity of speech, language, and communication needs and the trajectory of recovery given AAC intervention.

Clinical Features and Treatment Outcomes of Seronegative Pediatric Autoimmune Encephalitis

Background and Purpose

New diagnostic criteria for pediatric autoimmune encephalitis (AIE) have been introduced recently. A substantial proportion of cases of pediatric AIE are diagnosed as seronegative based on these criteria, and so the clinical characteristics of this group remain to be investigated.

Methods

This study included 46 pediatric patients younger than 18 years with suspected AIE. Clinical features, laboratory or radiological findings, and treatment outcomes were compared between seronegative and seropositive patients.

Results

Nine (19.6%) of the 46 patients were diagnosed as seropositive AIE. All of the patients with seropositive AIE had anti-N-methyl-D-aspartate receptor antibodies. Commonly identified neuropsychiatric symptoms were altered mental status, cognitive dysfunction, seizure, speech dysfunction, and psychotic disorder in both the seronegative and seropositive groups. Immunotherapy produced favorable treatment outcomes in both the seropositive (n=7, 77.8%) and seronegative (n=35, 94.6%) AIE patients. Treatment outcomes for first-line immunotherapy were better in seronegative AIE than seropositive AIE patients (p=0.003), and hence a smaller proportion of seronegative patients required second-line treatment (p=0.015).

Conclusions

Pediatric seronegative AIE patients showed clinical presentations similar to those of seropositive AIE patients, with favorable treatment outcomes after immunotherapy.

Clinical Features and Outcomes in Pediatric Autoimmune Encephalitis Associated With CASPR2 Antibody

Background: Contactin-associated protein-like 2 (CASPR2) neurological autoimmunity has been associated with various clinical syndromes involving central and peripheral nervous system. CASPR2 antibody-associated autoimmune encephalitis is mostly reported in adults. Analysis of the clinical presentation and prognostic data of CASPR2 antibody-associated autoimmune encephalitis in children remains important. Methods: A single-center retrospective review of children diagnosed with CASPR2 antibody-associated autoimmune encephalitis from June 1st, 2018 to October 31st, 2020. Results: Six patients were identified. The median age was 12 years (range 1.8-14), with an overall male predominance of 83% (5/6). Commonest clinical features were psychiatric symptoms (6/6), movement disorders (4/6), altered consciousness (3/6), sleep disorders (3/6), and headache (3/6). Four patients (4/6) received first-line therapy alone (steroids combined with intravenous immunoglobulins), and two patients (2/6) received second-line therapy (rituximab, mycophenolate mofetil, or cyclophosphamide). All patients showed no peripheral nervous system involvement. One patient had comorbidities with systemic lupus erythematosus. No evidence of neoplastic disease was found in the whole cohort. All patients had favorable outcomes (modified Rankin Score 0-2) with recurrence rate at 0%, respectively. Conclusion: CASPR2 antibody-associated autoimmune encephalitis is rare in children. Our findings suggest that this type of encephalitis seems to occur more frequently in older children. Patients respond well to immunotherapy and usually demonstrate a favorable clinical outcome. Associated tumors are extremely rare.

CASPR2 autoimmunity in children expanding to mild encephalopathy with hypertension

OBJECTIVE

To delineate autoimmune disease in association with contactin-associated protein 2 (CASPR2) antibodies in childhood, we reviewed the clinical phenotype of children with CASPR2 antibodies.

METHODS

Retrospective assessment of patients recruited through laboratories specialized in autoimmune CNS disease.

RESULTS

Ten children with serum CASPR2 antibodies were identified (age at manifestation 18 months to 17 years). Eight children with CASPR2 antibody titers from ≥1:160 to 1:5,120 had complex autoimmune diseases with an age-dependent clinical phenotype. Two children with structural epilepsy due to CNS malformations harbored nonspecific low-titer CASPR2 antibodies (serum titers 1:80). The clinical symptoms of the 8 children with high-titer CASPR2 antibodies were general weakness (8/8), sleep dysregulation (8/8), dysautonomia (8/8) encephalopathy (7/8), neuropathic pain (7/8), neuromyotonia (3/8), and flaccid paresis (3/8). Adolescents (3/8) showed pain, neuromyotonia, and encephalopathy, whereas younger children (5/8) displayed severe hypertension, encephalopathy, and hormonal dysfunction mimicking a systemic disease. No tumors were identified. Motor symptoms remitted with immunotherapy. Mild behavioral changes persisted in 1 child, and autism spectrum disorder was diagnosed during follow-up in a young boy.

CONCLUSION

High-titer CASPR2 antibodies are associated with Morvan syndrome in children as young as 2 years. However, CASPR2 autoimmunity mimics systemic disease and hypertensive encephalopathy in children younger than 7 years. The outcome following immunotherapy was mostly favorable; long-term behavioral impairment may occur in younger children.

Neuronal Antibodies and Associated Syndromes

INTRODUCTION

Multiple well-recognized conditions, such as Lambert-Eaton myasthenic syndrome (LEMS) and myasthenia gravis (MG), have been associated with neuronal antibodies.

MATERIALS AND METHODS

A search was performed using Embase, PubMed, and CINAHL. An initial search of each database was conducted using keywords and terms related to the aim of the current review. Additional articles were obtained by examining the reference lists and citations in the selected records.

RESULTS

The studies identified through the search process used different designs and methods to explore neuronal antibodies and associated syndromes. Previous studies have shown that neurological and psychiatric disorders can be mediated and influenced by various antibodies. The identification of autoantibodies can help with the accurate diagnosis of conditions and commencement of early treatment.

DISCUSSION

A review of selected studies identified in the literature implicated that classic anti-neuronal antibodies, such as anti-Ri and anti-Hu, play a role in the development of neurological diseases. More recent studies have indicated that other novel antibodies act on neuronal cell surface antigens to contribute to the development of neurological disorders.

CONCLUSION

Existing research provides evidence revealing a spectrum of antibodies linked to the development and progression of neurological diseases. However, further antibody testing and studies should be performed to validate the relationship between conditions and antibodies.

Late-onset anti-N-methyl-d-aspartate receptor encephalitis in China

PURPOSE

This study aimed to summarize the clinical characteristics and outcome of late-onset anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis in China.

METHOD

All cases of people with a definitive diagnosis of anti-NMDAR encephalitis in West China Hospital between June 2012 and April 2017 were retrospectively reviewed. The demographics, clinical characteristics, and outcome of those patients (age≥45years old) were summarized. Comparisons were conducted between older (≥45years old) and younger (18-44years old) adults.

RESULT

Eighteen (12%) of 151 people were ≥45years old, 9 of whom (50%) were female. Psychiatric symptoms were the most common clinical manifestations of older adults and presented in all individuals. At the last follow-up, 14 (78%) of them had a good outcome (modified Rankin Scale: 0-2) and one (6%) died. Compared with 121 younger adults, older adults had a higher proportion of presenting memory deficit as the initial symptom (17% vs. 2%, p=0.023), longer interval from onset to admission (30 vs. 13days, p=0.013), and longer interval from onset to diagnosis (42.5 vs. 24days, p=0.045). No older adults' condition was accompanied with teratoma compared with 75% of younger adults with tumor (p=0.032). And older adults had a tendency to have a lower rate of positive NMDAR antibody (Ab) in serum (28% vs. 52%, p=0.053).

CONCLUSION

Delayed admission and diagnosis are more common in older adults than in younger adults. A comprehensive consideration of all symptoms and early screening of NMDAR Ab, especially in cerebrospinal fluid, is necessary and beneficial to differential diagnosis.

Initial clinical presentation of young children with N-methyl-d-aspartate receptor encephalitis

Autoimmune encephalitis with anti-N-methyl-d-aspartate receptor autoantibodies (NMDA-R-Abs) is a recently described disease affecting adult and pediatric patients. Symptoms of the disease are now perfectly described in the adult population but the clinical presentation is less known in young children. The aim of the present study was to describe the clinical presentation and the specificities of symptoms presented by young children with NMDA-R-Abs encephalitis to improve diagnosis of this disease, and to compare these to a series of previously published female adult patients. Fifty cases of children younger than twelve years of age diagnosed with NMDA-R-Abs encephalitis between January 1, 2007 and December 31, 2016 (27 females and 23 males) were retrospectively studied. The first neurological symptoms observed in young children with NMDA-R-Abs encephalitis were characterized by seizure (72%), especially focal seizure (42%), within a median of 15 days before other encephalitis symptoms; other patients mostly had behavioral disorders (26%). The seizures were frequently difficult to diagnose because of the transient unilateral dystonic or tonic posturing presentation or sudden unilateral pain in the absence of clonic movements. A post-ictal motor deficit was also frequently observed. This clinical presentation is different from that observed in adult females with NMDA-R-Abs encephalitis who initially present mainly psychiatric disorders (67%) or cognitive impairment (19%), and less frequently seizures (14%). The diagnosis of NMDA-R-Abs encephalitis should be systematically considered in young children of both sexes who present neurological symptoms suggesting recent seizures (focal or generalized) without obvious other etiology.

Epidemiological Profile of Acute Viral Encephalitis

OBJECTIVE

To study the etiology and clinico-epidemiological profile of acute viral encephalitis in children with acute encephalitis syndrome (AES).

METHODS

An observational study including 100 patients fulfilling the criteria for AES was conducted in children of age group 1 mo - 16 y. Viral isolation was done on RD cells, HEp-2 cells and Vero cells from the cerebrospinal fluid samples of suspected viral encephalitis (VE) cases. An enzyme immunoassay for IgM antibodies was performed for measles, mumps, Varicella zoster virus (VZV), Herpes simplex virus 1 (HSV1) and Japanese encephalitis virus (JEV). Multiplex polymerase chain reaction (PCR) was done for Cytomegalovirus, Epstein Barr virus (EBV), HSV1 & 2, VZV, Enterovirus, Parecho virus, Human Herpes virus (HHV 6, 7) and Parvovirus B19. A micro neutralization test was performed for Enterovirus 71.

RESULTS

Out of enrolled 100 patients, 73 were of probable viral encephalitis. HSV1 (31.50%) was the commonest virus followed by Adenovirus (10.95%), Parvovirus (2.73%), JE virus (1.36%), Enterovirus (1.36%), EBV (1.36%), and mixed infection with HSV & EBV (1.36%). HSV 1 caused significant morbidity in children. The common computed tomography (CT) findings were hypodensities in the fronto- parietal lobe followed by cerebral edema.

CONCLUSIONS

The landscape of AES in India has changed in the previous decade, and both outbreak investigations and surveillance studies have increasingly reported non-JEV etiologies; because of these findings there is a need to explore additional strategies to prevent AES beyond vector control and JEV vaccination.

Expanding spectrum of contactin-associated protein 2 (CASPR2) autoimmunity-syndrome of parkinsonism and ataxia

Contactin-associated protein 2 (CASPR2) antibodies are originally associated with Morvan's syndrome and peripheral nerve hyper excitability. Our objective was to study retrospectively the clinical spectrum of CASPR2 antibody-positive patients in our hospital. This is a retrospective observational study. Patients treated at the Amrita Institute of Medical Sciences from May 2013 to April 2016, who were tested positive for CASPR2 antibodies, were included. A total of 1584 samples were tested in the neuroimmunology laboratory during the study period for voltage-gated potassium channel (VGKC) complex antibodies-leucine-rich glioma-inactivated protein 1 (LGI1) and CASPR2 antibodies. Thirty-four were positive for LGI1, 13 were positive for CASPR2, and 7 were for both (total 54-3.4% positivity). Of these 54 cases, 11 were treated in our hospital. Seven were positive for LGI1, three for CASPR2, and one for both. The patient who had both CASPR2 and LGI1 antibody positive had Morvan's syndrome. One patient with CASPR2 had neuromyotonia. The other patient was admitted with status epilepticus with a syndrome of parkinsonism and ataxia. The third patient had encephalopathy and myoclonus with a syndrome of parkinsonism and ataxia. Two of them underwent siddha treatment for other ailments prior to the onset of the disease for other ailments. Our short series shows the expanding spectrum of CASPR2 autoimmunity. Syndrome of parkinsonism and ataxia is an important manifestation of CASPR2 autoimmunity where we can offer a definitive treatment.

Treatment strategies for autoimmune encephalitis

Autoimmune encephalitis is one of the most rapidly growing research topics in neurology. Along with discoveries of novel antibodies associated with the disease, clinical experience and outcomes with diverse immunotherapeutic agents in the treatment of autoimmune encephalitis are accumulating. Retrospective observations indicate that early aggressive treatment is associated with better functional outcomes and fewer relapses. Immune response to first-line immunotherapeutic agents (corticosteroids, intravenous immunoglobulin, plasma exchange, and immunoadsorption) is fair, but approximately half or more of patients are administered second-line immunotherapy (rituximab and cyclophosphamide). A small but significant proportion of patients are refractory to all first- and second-line therapies and require further treatment. Although several investigations have shown promising alternatives, the low absolute number of patients involved necessitates more evidence to establish further treatment strategies. In this review, the agents used for first- and second-line immunotherapy are discussed and recent attempts at finding new treatment options are introduced.

Clinical characteristics, treatments, and outcomes of patients with anti-N-methyl-d-aspartate receptor encephalitis: A systematic review of reported cases

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a recently recognized autoimmune disorder which is responsive to immunotherapy. However, the outcomes of different immunotherapies have not been defined and there have been few studies that carried out a comparison among them. To provide an overview of the clinical characteristics, treatments, and outcomes of anti-NMDAR encephalitis, we systematically reviewed the literature in the PubMed, Medline, Embase, Cochrane Library, BioMedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), and Wan-fang databases. Eighty-three studies with a total of 432 patients were included. The median age was 22years. Two hundred ninety-three (68%) patients were female, 87 (21%) of 412 patients had a tumor, including 68 (78%) patients with ovarian teratoma. Pediatric patients had a higher ratio of seizures to psychiatric symptoms as the initial manifestation (p=0.0012), a lower proportion with a tumor (p<0.0001) and CSF pleocytosis (p=0.0163), and a better outcome (p=0.0064) than adults. Patients who died had a higher proportion of CSF pleocytosis than the patients who survived (p=0.0021). There were no significant differences among three first-line immunotherapy used alone (p=0.9172) or among combinations of every two of them (p=0.3059). With regard to the use of corticosteroid and IVIG, there were no significant differences between the outcomes of early combined treatment and sequential treatment (p=0.7277), or between using corticosteroid first and IVIG first (p=0.5422). Our findings suggest that the clinical characteristics and outcomes for pediatric patients were different from adult patients, and no significant differences were found among different immunotherapies.

Magnetic resonance imaging and magnetic resonance spectroscopy in a young male patient with anti-N-methyl-D-aspartate receptor encephalitis and uncommon cerebellar involvement: A case report with review of the literature

We report a case of a 17-year-old man presenting with new onset psychiatric symptoms. Magnetic resonance imaging (MRI) and proton magnetic resonance (MR) spectroscopy revealed some lesions in the right cerebellar hemisphere and ipsilateral cerebellar tonsil suggestive of encephalitis. An extensive workup was negative for both infectious and neoplastic diseases and he was afterward diagnosed with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. This disorder is an autoimmune encephalitis, highly lethal but curable, predominantly found in young female with ovarian teratoma. He received methylprednisolone. His clinical findings gradually improve and he made a complete recovery. Accordingly, repeated brain MRI and proton MR spectroscopy showed a gradual reduction of the lesions; MRI taken six months after starting therapy showed complete resolution of the lesions. Our case shows that, although rare, anti-NMDAR encephalitis should be considered also in young men for whom a rapid onset of psychiatric neurological disorders cannot be explained by more frequent causes. Our report underlines also the usefulness of MRI and proton MR spectroscopic findings in the diagnosis and follow-up of this disease.