Antibody-negative Autoimmune Encephalitis Research Articles

18F-DPA714 PET/MRI as a potential imaging tool for detecting possible antibody-negative autoimmune encephalitis: a prospective study.

Conventional magnetic resonance imaging (MRI) used for detecting possible antibody-negative autoimmune encephalitis (AIE) often fails to meet the diagnostic requirements of this disease. Positron emission tomography (PET) with a translocator protein radioligand can help visualize microglia distribution density in inflammation-related diseases, thereby offering potentially incremental value to conventional MRI for the in vivo assessment of possible antibody-negative AIE. In this prospective study, 15 participants diagnosed with possible antibody-negative AIE and 10 healthy controls were enrolled (ClinicalTrials.gov: NCT05293405, dated March 15, 2022). All participants underwent hybrid 18F-DPA714 PET/MRI and evaluation for modified Rankin scale (mRS) score, clinical assessment scale for AIE (CASE), and appropriate antibodies. A positive finding was defined as the intensity of 18F-DPA714 uptake that was above a threshold of mean standardized uptake value ratio (SUVR) + two standard deviations of SUVR within the corresponding brain regions of healthy controls. The positive detection rate of 18F-DPA714 PET for possible antibody-negative AIE was significantly higher than that of brain MRI (10/15 [67%] vs. 3/15 [20%]; P = 0.039). In addition, both the intensity and extent of 18F-DPA714 uptake were significantly associated with the CASE score (P = 0.002 and 0.001). Meanwhile, SUVR levels in the cerebellar region were significantly higher in patients with ataxia than in those without ataxia (P = 0.006). Furthermore, 18F-DPA714 uptake decreased in 5/10 [50%] patients who underwent follow-up PET/MRI, which mirrored their symptom relief. 18F-DPA714 PET demonstrated its potentially incremental value to conventional MRI for detecting possible antibody-negative AIE.

Study on clinical features and factors related to long-term outcomes of antibody-negative autoimmune encephalitis.

To delineate the clinical characteristics of antibody-negative autoimmune encephalitis (AE) and to investigate factors associated with long-term outcomes among antibody-negative AE. Patients diagnosed with antibody-negative AE were recruited from January 2016 to December 2022 at the Second Xiangya Hospital of Central South University. The study assessed the long-term outcomes of antibody-negative AE using the modified Rankin scale (mRS) and the Clinical Assessment Scale in Autoimmune Encephalitis (CASE). Predictors influencing long-term outcomes were subsequently analyzed. External validation of RAPID scores (refractory status epilepticus [RSE], age of onset ≥60 years, ANPRA [antibody-negative probable autoimmune encephalitis], infratentorial involvement, and delay of immunotherapy ≥1 month) was performed. In total, 100 (47 females and 53 males) antibody-negative AE patients were enrolled in this study, with approximately 49 (49%) experiencing unfavorable long-term outcomes (mRS scores ≥3). Antibody-negative AE was subcategorized into ANPRA, autoimmune limbic encephalitis (LE), and acute disseminated encephalomyelitis (ADEM). Psychiatric symptoms were prevalent in LE and ANPRA subtypes, while weakness and gait instability/dystonia were predominant in the ADEM subtype. Higher peak CASE scores (odds ratio [OR] 1.846, 95% confidence interval [CI]: 1.163-2.930, p = 0.009) and initiating immunotherapy within 30 days (OR 0.210, 95% CI: 0.046-0.948, p = 0.042) were correlated with long-term outcomes. Receiver operating characteristic (ROC) analysis returned that the RAPID scores cutoff of 1.5 best discriminated the group with poor long-term outcomes (sensitivity 85.7%, specificity 56.9%). The ANPRA subtype exhibited poorer long-term outcomes compared to LE and ADEM subtypes, and early immunotherapy was crucial for improving long-term outcomes in antibody-negative AE. The use of RAPID scoring could aid in guiding clinical decision making.

Clinical features and immunotherapy outcomes in antibody-negative autoimmune encephalitis: a retrospective case-control study.

This study aimed to compare clinical features, laboratory findings, and immunotherapy responses between antibody-positive and antibody-negative Autoimmune encephalitis (AE) patients. A retrospective analysis of clinical data from 60 AE patients (33 antibody-positive, 27 antibody-negative) diagnosed at Zhongshan Hospital of Xiamen University between January 1, 2016, and March 1, 2024 was conducted. Disease severity and treatment response were assessed using the modified Rankin Scale (mRS) and the Clinical Assessment Scale for Autoimmune Encephalitis (CASE). Antibody-positive AE patients more frequently presented with multiple symptoms (≥4 symptoms: 39.4% vs. 14.8%, p = 0.036). They demonstrated significantly elevated serum IgG concentrations (p = 0.010) and cerebrospinal fluid (CSF) leukocyte counts (p = 0.014). Conversely, antibody-negative AE patients presented with higher CSF total protein levels (p = 0.025) and albumin quotients (p = 0.018), indicative of more severe blood-brain barrier disruption. Antibody-positive AE patients more frequently received combination first-line immunotherapy (75.8% vs. 48.1%, p = 0.027) and exhibited superior treatment outcomes (90.9% vs. 70%, p = 0.022). Among critically ill patients (peak mRS score: 4-5), improvement in CASE scores was markedly greater in the antibody-positive cohort (median: 4.50 vs. 1.00, p = 0.024). Antibody-positive AE patients manifested a more diverse symptom spectrum, elevated serum IgG concentrations and CSF leukocyte counts, and superior responses to immunotherapy. In contrast, antibody-negative AE patients demonstrated more severe blood-brain barrier dysfunction, as evidenced by higher CSF total protein concentrations and albumin quotients.

Antibody-Negative Autoimmune Encephalitis: A Single-Center Retrospective Analysis.

Autoimmune encephalitis (AE) refers to a heterogenous group of inflammatory CNS diseases. Subgroups with specified neural autoantibodies are more homogeneous in presentation, trigger factors, outcome, and response to therapy. However, a considerable fraction of patients has AE features but does not harbor detectable autoantibodies and is referred to as antibody-negative AE. Our aim was to describe clinical features, trigger factors, treatments, and outcome of a cohort of comprehensively tested antibody-negative AE patients. This retrospective monocentric study recruited adult patients whose serum and/or CSF was sent to our tertiary center for neural antibody testing between 2011 and 2020, who entered the diagnostic algorithm as possible antibody-negative AE and had the following: (1) probable antibody-negative AE, definite antibody-negative acute disseminated encephalomyelitis (ADEM), or definite autoimmune limbic encephalitis (LE) according to diagnostic criteria; (2) available data on MRI of the brain, CSF, and EEG; and (3) stored serum and/or CSF samples. These samples were reanalyzed using a comprehensive combination of cell-based and tissue-based assays. Of 2,250 patients tested, 33 (1.5%) were classified as possible antibody-negative AE. Of these, 5 were found to have antibodies by comprehensive testing, 5 fulfilled the criteria of probable AE (3F:2M, median age 67, range 42-67), 4 of definite autoimmune LE (2F:2M, median age 45.5, range 27-60 years), one of definite antibody-negative ADEM, 2 of Hashimoto encephalopathy, one had no samples available for additional testing, and 15 had no further categorization. Of 10 probable/definite AE/LE/ADEM, one had a malignancy and none of them received an alternative diagnosis until the end of follow-up (median 18 months). In total, 80% (8/10) of patients received immunotherapy including corticosteroids, and 6/10 (60%) patients received rituximab, azathioprine, cyclophosphamide, plasma exchange, or IV immunoglobulins. Five (50%) patients improved, one (10%) stabilized, one (10%) worsened, and 3 (30%) died. All deaths were considered to be related to encephalitis. We did not observe differences of immunotherapy-treated patients in likelihood of improvement with or without nonsteroidal immunotherapy (with 2/6, without 1/2). Antibody-negative AE should be diagnosed only after comprehensive testing. Diagnostic effort is important because many patients benefit from immunotherapy and some have malignancies.

Caution to Poor Adherence With Immunosuppressant Medication That Causes Coma-Onset Autoimmune Encephalitis: A Case Report and Literature Review

Autoimmune encephalitis after liver transplantation (LT) is a rare disorder. This is because patients are usually in an immunosuppressed state after LT. Here, we report a rare case of autoantibody-negative autoimmune-encephalitis-induced coma after living-donor (LD) LT. A 45-year-old woman who underwent LDLT for primary biliary cholangitis (PBC) was brought to our hospital with the chief complaint of cognitive deficiency and an episode of memory loss. Physical examination, laboratory tests, and cerebrospinal fluid analysis revealed no significant findings. However, diffusion-weighted magnetic resonance imaging showed hyperintensity in the bilateral hippocampus. No autoantibodies associated with autoimmune encephalitis were detected. The diagnosis of antibody-negative autoimmune encephalitis was made on the basis of low immunosuppressive drug levels in the blood (indicative of poor adherence) and the presence of PBC as the autoimmune disease. The patient regained consciousness after intravenous methylprednisolone pulse therapy and plasma exchange. This case highlights that when examining patients with impaired consciousness after LDLT, it is important to consider autoimmune encephalitis as a potential diagnosis.

Evaluation of multiple consensus criteria for autoimmune encephalitis and temporal analysis of symptoms in a pediatric encephalitis cohort.

ObjectiveTo evaluate the sensitivity and specificity of current criteria for the diagnosis of autoimmune encephalitis (AE) and the temporal onset of neuropsychiatric symptoms (NP) in a pediatric encephalitis cohort.BackgroundMultiple criteria for AE have been developed, including the Graus and pediatric-focused Cellucci consensus criteria, and the Determining Etiology in Encephalitis (DEE) score for patients with encephalitis. Early identification and treatment of AE is crucial to improve outcomes, but this can be difficult given the frequent overlap of clinical presentation between AE and infectious encephalitis (IE).Design/methodsA retrospective review was conducted of patients seen at our institution from 2000 to 2021 with a final diagnosis of AE or IE. These were narrowed through multiple exclusions to etiology-confirmed IE or antibody-positive/negative AE. Time of onset or results of all symptoms and diagnostics were recorded. Sensitivity and specificity of each criterion under various clinical scenarios were calculated over the first month after initial NP symptom onset.ResultsA total of 23 antibody-positive AE, 9 antibody-negative AE and 23 IE patients were included in final analysis. Under an idealized scenario with rapid initial diagnostic evaluations, the sensitivity for pediatric AE by day 28 after onset of NP symptoms approached 90% for both Cellucci and Graus criteria. Specificity within these 28 days was low without infectious testing results, increasing the greatest with rapid PCR testing and second with infectious antibody testing—reaching ~90% with both. A DEE score of 3 provided a specificity of 100% in identifying IE, but low sensitivity (29%). Symptoms were noted to cluster within several days of onset in IE, but in AE were spread out. Personality/behavioral change, speech change, affective disorder, and sleep disturbance were noted more often in AE, while fever, elevated C-reactive protein or CSF protein, and abnormal MRI-Brain occurred more often in IE.ConclusionIn this study, we provide the first evaluation of the Cellucci criteria and the first validation of the DEE score in the differentiation of pediatric AE and IE. Further refinement of AE criteria is needed to improve early detection and treatment of pediatric AE.

Clinical Characteristics and Prognosis of Antibody-Negative Autoimmune Encephalitis in Children: A Single-Center Retrospective Study

BackgroundAutoimmune encephalitis (AE) is a group of immune-mediated brain diseases. However, new diagnostic criteria for AE in children indicate that partial pediatric patients with AE may be diagnosed without evidence of positive autoantibodies. Therefore, the clinical characteristics and prognosis of children with antibody-negative but probable AE require further investigation. MethodsForty-one children with AE admitted to our hospital from April 2014 to January 2021 were retrospectively enrolled in this study. Children were divided into two groups according to positive or negative antibody tests. Clinical characteristics, cerebrospinal fluid, video electroencephalography, brain magnetic resonance imaging, and prognosis were analyzed, and the correlation between modified Rankin scale (mRS) and neutrophil-to-lymphocyte ratio (NLR) was examined. ResultsOf 41 children, 16 cases tested positive for autoantibodies. The main features were psychiatric symptoms, cognitive disturbances, speech disturbances, movement disorders, and seizures. All the children were given a combination of intravenous methylprednisolone pulses with intravenous immunoglobulin therapy; 26 cases (63%) had a good outcome, and 15 cases (37%) had a poor outcome. Antibody-positive and antibody-negative but probable AE were analyzed by univariate analysis and showed lower lymphocyte counts and higher NLR and mRS scores in the antibody-negative group (P < 0.05). The Spearman rank correlation analysis showed a positive correlation between NLR level and mRS scores (P < 0.05). ConclusionsAntibody-negative but possible AE is frequent in children who may have a more severe neurological impairment and higher NLR than antibody-positive AE. Aggressive immunotherapy in antibody-negative AE is essential to achieve a good prognosis.

Autoimmune Encephalitis in Children: A Case Series at a Tertiary Care Center.

Autoimmune encephalitis is the third most common cause of encephalitis in children. We provide a detailed account of presenting symptoms, diagnosis, and response to treatment in pediatric autoimmune encephalitis patients evaluated at University of California San Francisco within a 2.5-year period. Eleven were identified: anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis (n = 4), antibody-negative autoimmune encephalitis (n = 4), steroid-responsive encephalopathy associated with thyroiditis (SREAT) (n = 2), and glial fibrillary acidic protein (GFAP)-associated encephalitis (n = 1). Most common presenting symptoms included seizures and behavior changes (54%). More than 90% of patients showed improvement following first-line immunotherapy (high-dose corticosteroids, intravenous immunoglobulin, and/or plasma exchange). A total of 64% received second-line treatment with rituximab, cyclophosphamide, or mycophenolate mofetil. One patient with NMDAR encephalitis died despite escalating immunotherapy. None of the patients showed complete recovery after median follow-up of 9 months (range 0.5-66). Children with autoimmune encephalitis have a diverse clinical presentation and may lack an identifiable autoantibody. Majority of patients show a good response to immunotherapy; however, recovery can be delayed.

Early diagnosis of autoimmune encephalitis

Autoimmune encephalitis is a group of treatable autoimmune diseases of central nervous system.Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most common autoimmune encephalitis.Some of autoimmune encephalitis can be confirmed by specific autoantibodies, but excessive dependence on autoantibody detection usually leads to delayed treatment.This article reviews the clinical presentations of pediatric anti-NMDAR encephalitis and the antibody-negative autoimmune encephalitis so as to improve the pediatricians understanding on the diseases. Key words: Autoimmune encephalitis; Anti-N-methyl-D-aspartate receptor encephalitis; Antibody-negative autoimmune encephalitis

Antibody negative autoimmune encephalitis- Does it differ from definite one?

Context:Autoimmune encephalitis (AE) is an emerging cause of non-infective encephalitis, presentations of which vary widely. Traditionally the diagnosis of AE is based on detection of antibodies in a patient with clinical picture suggestive of AE.Aim:To evaluate the clinical characteristics and response to immunotherapy in patients with antibody negative autoimmune encephalitis and to compare them with definite cases.Settings and Design:A prospective follow-up study was done in patients presenting with presumptive symptoms of AE from January 2017 to January 2019. The study was done in a tertiary care institute of Northern India.Patients and Methods:Demographic and clinical parameters were noted and relevant investigations for management were done according to well-defined protocol. The patients were treated with immunomodulatory therapy in the form of steroids and/or intravenous immunoglobulins (IVIg). They were followed up for treatment response and relapse at 2 monthly intervals.Statistical Analysis Used:The data was expressed as either proportions or mean/median. Chi-square test/Independent T test was used to compare antibody positive and antibody negative group.Results:Out of 31 patients with presumptive AE, 16 patients tested positive for autoimmune antibodies (definite AE). Incidences of seizure, behavioral abnormalities, dementia and altered sensorium were similar between the 2 groups (p > 0.05). Complete or partial response was seen in all treated patients in both groups with no significant difference (p 0.716). CSF protein concentration and cellularity were higher in the definite group although only high protein concentration could reach statistical significance (p 0.002). Malignancy could be confirmed after extensive search in 2 out of 16 patients with definite AE and in 1 out of 15 antibody negative AE patients.Conclusions:Clinical presentation of antibody negative cases does not differ significantly from definite ones. Since treatment response is also similar in both the groups, starting immunotherapy in a patient presenting with presumptive symptoms of AE, while ruling out other common mimickers, seems to be the need of the hour in the management of this evolving entity.

Evaluation of Clinical and Paraclinical Findings for the Differential Diagnosis of Autoimmune and Infectious Encephalitis.

Background: The differential diagnosis of autoimmune and infectious encephalitis is notoriously difficult. For this study, we compare the presenting clinical symptoms and paraclinical test results of autoimmune and infectious encephalitis patients. A clinical algorithm for the diagnosis of autoimmune encephalitis has recently been published. We test these Graus criteria on our cohort for diagnostic sensitivity and specificity within the first week of presentation.Methods: We included all patients seen at our department within a 10-year-period who were diagnosed with encephalitis. The discharge diagnoses served as the reference standard for testing the clinical algorithm for two conditions: use of all the clinical information available on a patient during the first week of hospital admission assuming undefined autoantibody status and microbiological test results (C1) vs. consideration of all the information available on a patient, including the results of serological and microbiological testing (C2).Results: Eighty-four patients (33 autoimmune, 51 infectious encephalitis) were included in the study. Fifty-one (17 autoimmune, 34 infectious) had a definite clinical diagnosis. The two groups differed significantly for the presence of headache, fever, epileptic seizures, and CSF cell-count at presentation. Application of the clinical algorithm resulted in a low sensitivity (58%) and very low specificity (8%) for the diagnosis of possible autoimmune encephalitis. The latter increased considerably in the subgroups of probable and definite autoimmune encephalitis. Whereas the sensitivity of the individual diagnostic categories was clearly time-dependent, the specificity rested foremost on the knowledge of the results of microbiological testing. Anti-CASPR2- and -LGI1-associated autoimmune encephalitis and tick-borne virus encephalitis presented particular diagnostic pitfalls.Conclusions: We define clinical symptoms and paraclinical test results which prove valuable for the differentiation between infectious and autoimmune encephalitis. Sensitivity and specificity of the clinical algorithm clearly depended on the amount of time passed after hospital admission and knowledge of microbiological test results. Accepting this limitation for the acute setting, the algorithm remains a valuable diagnostic aid for antibody-negative autoimmune encephalitis or in resource-poor settings. The initiation of immune therapy however should not be delayed if an autoimmune etiology is considered likely, even if the diagnostic criteria of the algorithm are not (yet) fulfilled.

P 107 Antibody-negative autoimmune encephalitis?

We report about a 66-year-old woman which has been hospitalized with suspected antibody-negative autoimmune encephalitis. The patient experienced relapsing episodes with disorientation, amnestic aphasia, short-term memory dysfunction, hallucinations, apraxia, ataxia, seizures and severe delirium during the years 2012–2013. In medical history the patient has had a breast cancer right sided (first diagnosis 2010) with breast-conserving therapy, radiation and hormone therapy. MRI and cerebrospinal fluid (including antibodies for autoimmunencephalitis) did not show relevant abnormalities. The symptoms completely remitted after cortison therapy. After several episodes, azathioprin therapy was started resulting in clinical stability without relapses. In July 2016 azathioprin was discontinued. In October 2016 the patient developed similar symptoms and hospitalized. As in previous brain scans, MRI was normal without signs of encephalitis. Electroencephalogram showed a severe slowing most pronounced in frontal regions without epileptiform patterns. In cerebrospinal fluid cell count was normal, total protein was elevated (∼1300 mg/l). There was no evidence of bacterial or viral infection. F-18-FDG-PET showed a reduced tracer uptake frontal, parietal and temporal on both sides. A whole body PET-CT, skeletal scintigraphy and mammography did not reveal any malignant tumors. During the following days the patient experienced a rapid worsening in orientation, developed anarthria and was unable to eat independently. Routine blood investigations were without any abnormalities. Autoantibodies to surface antigens and paraneoplastic antibodies as well as vasculitis associated parameters were negative. However, we found highly elevated antibodies against thyreoperoxidase (2726 U/ml, normal < 60). We started steroid pulse therapy and the patient improved rapidly. She regained orientation and improved in ability to communicate. She could move and eat independently. Complete remission was achieved within one week. The patient described complete amnesia regarding this episode. We restarted immunosuppressive therapy with azathioprin. At discharge the patient is able to carry out usual activities. In conclusion we diagnosed a SREAT (steroid responsive encephalopathy in association with autoimmunthyreoditis) with relapsing episodes of amnestic aphasia, disorientation, memory-dysfunctions, delirium, apraxia, and ataxia with highly elevated TPO-antibodies and complete remission after cortison therapy. MRI findings: Unspecific T2/FLAIR Hyperintensities bifrontal. Electroencephalogram: severe slowing most pronounced in frontal regions without epileptiform patterns.