Autoimmune glial fibrillary acidic protein astrocytopathy with anti-NMDAR and sulfatide-IgG-positive encephalitis overlap syndrome: A case report and literature review.

RATIONALE: Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a rare autoimmune disease of the central nervous system that affects the meninges, brain, spinal cord, and optic nerves. GFAP astrocytopathy can coexist with a variety of antibodies, which is known as overlap syndrome. Anti-NMDAR-positive encephalitis overlap syndrome has been reported; however, encephalitis overlap syndrome with both anti-NMDAR and sulfatide-IgG positivity has not been reported. PATIENT CONCERNS: The patient was a 50-year-old male who was drowsy and had chills and weak limbs for 6 months. His symptoms worsened after admission to our hospital with persistent high fever, dysphoria, gibberish, and disturbance of consciousness. Positive cerebrospinal fluid NMDA, GFAP antibodies, and serum sulfatide antibody IgG were positive. DIAGNOSES: Autoimmune GFAP astrocytopathy with anti-NMDAR and sulfatide-IgG-positive encephalitis overlap syndrome. INTERVENTIONS: In addition to ventilator support and symptomatic supportive treatment, step-down therapy with methylprednisolone (1000 mg/d, halved every 3 days) and pulse therapy with human immunoglobulin (0.4 g/(kg d) for 5 days) were used. OUTCOMES: After 6 days of treatment, the patient condition did not improve, and the family signed up to give up the treatment and left the hospital. CONCLUSIONS: Patients with autoimmune GFAP astrocytopathy may be positive for anti-NMDAR and sulfatide-IgG, and immunotherapy may be effective in patients with severe conditions. LESSONS: Autoimmune GFAP astrocytopathy with nonspecific symptoms is rarely reported and is easy to be missed and misdiagnosed. GFAP astrocytopathy should be considered in patients with fever, headache, disturbance of consciousness, convulsions, and central infections that do not respond to antibacterial and viral agents. Autoimmune encephalopathy-related antibody testing should be performed as soon as possible, early diagnosis should be confirmed, and immunomodulatory therapy should be administered promptly.

Nonverbal Cognitive Skills in Children With Aicardi Goutières Syndrome.

BACKGROUND AND OBJECTIVES: Aicardi Goutières syndrome (AGS) is type I interferonopathy characterized by severe neurologic impairment. Although many children with AGS demonstrate motor and expressive language deficits, the magnitude of receptive language impairment is uncharacterized. We sought to characterize cognitive function in AGS-affected children using assessment tools with reduced dependence on motor abilities and compare cognitive testing outcomes with overall severity and parental assessment of adaptive behavior. METHODS: We performed a cross-sectional study. Children were recruited as part of the Myelin Disorders Biorepository Project at the Children's Hospital of Philadelphia. We included individuals with a confirmed diagnosis of AGS. We administered the Leiter International Performance Scale, third edition (Leiter-3), and the Vineland Adaptive Behavior Scale, third edition (VABS-3), in the context of research encounters. Motor skills were categorized by AGS Severity Scale mobility levels. Descriptive statistics and Spearman's rank correlation were used to compare assessments. Mann-Whitney and Kruskal-Wallis tests with correction with Dunn's multiple comparison test were used to compare test performance between mobility groups. RESULTS: Cognitive and adaptive behavior performance was captured in 57 children. The mean age at encounters was 8.51 (SD 5.15) years. The median (IQR) Leiter-3 score was 51 (interquartile range [IQR] 60), with administration failure in 20 of 57 (35%) individuals. On the VABS-3, the Motor Domain (median 29, IQR 36.25) was more impacted than the Communication (median 50, IQR 52), Daily Living Skills (median 52, IQR 31), and Socialization (median 54, IQR 40) Domains (p < 0.0001). The AGS Scale correlated with VABS-3 (r = 0.86, p < 0.0001) and Leiter-3 (r = 0.87, p < 0.0001). There was correlation between VABS-3 Domains and Leiter-3 (r-range 0.83-0.97). Gross motor and fine motor categories, respectively, correlated with VABS-3 (H = 39.37, p < 0.0001; U = 63, p < 0.0001) and Leiter-3 (H = 40.43, p < 0.0001; U = 66, p < 0.0001). Within each gross motor and fine motor category of the AGS Scale, a subset of children scored within normal IQ range. DISCUSSION: Parental assessment of function by the VABS-3 correlated with directly assessed performance measures. Our data underscore the potential value of VABS-3 and Leiter-3 as tools to assess psychometric function in AGS. With a deeper understanding of our patients' abilities, we can better guide clinicians and families to provide appropriate support and personalized interventions to empower children with leukodystrophies to maximize their communication and educational potential.

[Autoimmune Nodopathy].

Autoimmune nodopathy (AN), a newly established category of autoimmune disease, refers to an immune-mediated neuropathy associated with development of autoantibodies against membrane proteins, including neurofascin 186, neurofascin 155, contactin-1, and contactin-associated protein 1 located in the nodes of Ranvier or paranodes. Subclass analysis of these autoantibodies reveals predominant elevation of immunoglobulin (G4. Patients with AN show clinical and laboratory characteristics such as distal-predominant sensorimotor disturbance, sensory ataxia, poor response to intravenous immunoglobulin, and highly elevated cerebrospinal fluid protein levels. B cell-depletion therapy using an anti-CD20 monoclonal antibody is effective for patients with AN. Autoantibody measurement is beneficial not only for diagnosis but also for deciding treatment strategies for AN.

Autoimmune encephalitis in glial fibrillary acidic protein astrocytopathy.

Autoimmune encephalitis due to glial fibrillar acidic protein (GFAP) astrocytopathy is a rare cause of subacute neuropsychiatric changes. In this case, a young patient presented with a viral prodrome and meningismus, followed by progressive encephalopathy and movement disorders over the span of 2 weeks. Due to his clinical trajectory, inflammatory cerebrospinal fluid (CSF) analysis, initial normal brain imaging and negative serum autoimmune encephalopathy panel, his initial diagnosis was presumed viral meningoencephalitis. The recurrence and progression of neuropsychiatric symptoms and myoclonus despite antiviral treatment prompted further investigation, inclusive of testing for CSF autoimmune encephalopathy autoantibodies, yielding a clinically meaningful, positive GFAP autoantibody. This case highlights the importance of appropriately testing both serum and CSF autoantibodies when an autoimmune encephalitic process is considered. Through this case, we review the clinical and radiographic manifestations of GFAP astrocytopathy, alongside notable pearls pertaining to this autoantibody syndrome and its management.

The inflamed brain.

Autoimmune conditions underlie some cases of psychosis. Scientists are expanding their search for patients, who often benefit from treatment.

[Autoimmune Autonomic Ganglionopathy and Acute Autonomic Sensory Neuropathy].

Autoimmune autonomic ganglionopathy (AAG) and acute autonomic sensory neuropathy (AASN) are immune-mediated neuropathies that affect the autonomic and/or dorsal root ganglia. Autoantibodies against the nicotinic ganglionic acetylcholine receptor (gAChR) detected in the sera of patients with AAG play a key role in the pathogenesis of this condition. Notably, gAChR antibodies are not detected in the sera of patients with AASN. Currently, AAG and AASN are not considered to be on the same spectrum with regard to disease concept based on clinical symptoms and laboratory findings. However, extra-autonomic brain symptoms (including psychiatric symptoms and personality changes) and endocrine disorders occur in both diseases, which suggests shared pathophysiology between the two conditions.

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

OBJECTIVE: To delineate the clinical characteristics of antibody-negative autoimmune encephalitis (AE) and to investigate factors associated with long-term outcomes among antibody-negative AE. METHODS: 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. RESULTS: 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%). INTERPRETATION: 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.

Inter-laboratory comparison of routine autoantibody detection methods for autoimmune neuropathies and myasthenia gravis.

Serological tests are important to detect autoantibodies (autoAbs) in patients with autoimmune neuropathies (AN) and myasthenia gravis (MG) as they are biomarkers for diagnosis, stratification, treatment selection, and monitoring. However, tests to detect autoAbs frequently lack proper standardization and results differ across diagnostic laboratories. We compared results for tests routinely performed in Spanish diagnostic laboratories to detect AN and MG autoAbs. In the Spanish Society of Immunology Autoimmunity Group national workshop, serum samples from 13 patients with AN or MG were tested for anti-ganglioside, anti-myelin-associated glycoprotein (MAG), anti-nicotinic acetylcholine receptor (AChR), and anti-muscle-specific kinase (MuSK) autoAbs using reference methods and were distributed for analysis to 27 participating laboratories using their routine methods. Overserved were inter-laboratory variability and worryingly low sensitivity, especially for anti-ganglioside immunoglobulin G and anti-MAG autoAb detection. This pilot study reflects autoAbs detection state of the art in AN and MG testing in leading diagnostic laboratories in Spain, highlighting the need for standardization prior to clinical use.

Seroprevalence of neuronal antibodies in diseases mimicking autoimmune encephalitis.

Detection of neuronal antibodies for autoimmune encephalitis and paraneoplastic neurological syndromes relies on commercially available cell-based assays and lineblots. However, lineblots may reveal the presence of neuronal antibodies in patients with various non-autoimmune etiologies. Herein we describe patients with non-autoimmune etiologies (cohort B) and detectable neuronal antibodies and compare them to definite cases of autoimmune encephalitis (cohort A) for differences in clinical data. All patients positive for at least one neuronal antibody were retrospectively evaluated for autoimmune encephalitis and/or paraneoplastic neurological syndrome between 2016 and 2022. 39 cases in cohort B and 23 in cohort A were identified. In cohort B, most common diagnoses were neurodegenerative disorders in 9/39 (23.1%), brain tumors in 6/39 (15.4%) while most common detected antibodies were anti-titin (N10), anti-recoverin (N11), anti-Yo (N8) and all were detected in serum only. Differential aspects between cohort A and B were CSF pleocytosis (14/23 (60.8%) vs 11/35 (31.4%), p = 0.042, respectively), MRI features suggestive of encephalitis (6/23 (26.1%) vs 0 (0%), p = 0.002, respectively) and epilepsy restricted to temporal lobes (14/23 (60.9%) vs 2/30 (6.7%), p = 0.0003, respectively). A large proportion of lineblot results were non-specific when only serum was tested and were frequently found in non-autoimmune neurological conditions.

Autoimmune central nervous system disorders: Antibody testing and its clinical utility.

A rapidly expanding repertoire of neural antibody biomarkers exists for autoimmune central nervous system (CNS) disorders. Following clinical recognition of an autoimmune CNS disorder, the detection of a neural antibody facilitates diagnosis and informs prognosis and management. This review considers the phenotypes, diagnostic assay methodologies, and clinical utility of neural antibodies in autoimmune CNS disorders. Autoimmune CNS disorders may present with a diverse range of clinical features. Clinical phenotype should inform the neural antibodies selected for testing via the use of phenotype-specific panels. Both serum and cerebrospinal fluid (CSF) are preferred in the vast majority of cases but for some analytes either CSF (e.g. N-methyl-D-aspartate receptor [NMDA-R] IgG) or serum (e.g. aquaporin-4 [AQP4] IgG) specimens may be preferred. Screening using 2 methods is recommended for most analytes, particularly paraneoplastic antibodies. We utilize murine tissue-based indirect immunofluorescence assay (TIFA) with subsequent confirmatory protein-specific testing. The cellular location of the target antigen informs choice of confirmatory diagnostic assay (e.g. blot for intracellular antigens such as Hu; cell-based assay for cell surface targets such as leucine-rich glioma inactivated 1 [LGI1]). Titers of positive results have limited diagnostic utility with the exception of glutamic acid decarboxylase (GAD) 65 IgG autoimmunity, which is associated with neurological disease at higher values. While novel antibodies are typically discovered using established techniques such as TIFA and immunoprecipitation-mass spectrometry, more recent high-throughput molecular technologies (such as protein microarray and phage-display immunoprecipitation sequencing) may expedite the process of antibody discovery. Individual neural antibodies inform the clinician regarding the clinical associations, oncological risk stratification and tumor histology, the likely prognosis, and immunotherapy choice. In the era of neural antibody biomarkers for autoimmune CNS disorders, access to appropriate laboratory assays for neural antibodies is of critical importance in the diagnosis and management of these disorders.

Autoimmune and inflammatory neurological disorders in the intensive care unit.

PURPOSE OF REVIEW: The present review summarizes the diagnostic approach to autoimmune encephalitis (AE) in the intensive care unit (ICU) and provides practical guidance on therapeutic management. RECENT FINDINGS: Autoimmune encephalitis represents a group of immune-mediated brain diseases associated with antibodies that are pathogenic against central nervous system proteins. Recent findings suggests that the diagnosis of AE requires a multidisciplinary approach including appropriate recognition of common clinical syndromes, brain imaging and electroencephalography to confirm focal pathology, and cerebrospinal fluid and serum tests to rule out common brain infections, and to detect autoantibodies. ICU admission may be necessary at AE onset because of altered mental status, refractory seizures, and/or dysautonomia. Early management in ICU includes prompt initiation of immunotherapy, detection and treatment of seizures, and supportive care with neuromonitoring. In parallel, screening for neoplasm should be systematically performed. Despite severe presentation, epidemiological studies suggest that functional recovery is likely under appropriate therapy, even after prolonged ICU stays. CONCLUSION: AE and related disorders are increasingly recognized in the ICU population. Critical care physicians should be aware of these conditions and consider them early in the differential diagnosis of patients presenting with unexplained encephalopathy. A multidisciplinary approach is mandatory for diagnosis, ICU management, specific therapy, and prognostication.

Intracranial calcifications simulating Aicardi-Goutières syndrome in PARS2-related mitochondrial disease.

PARS2 encodes an aminoacyl-tRNA synthetase that catalyzes the ligation of proline to mitochondrial prolyl-tRNA molecules. Diseases associated with PARS2 primarily affect the central nervous system, causing early infantile developmental epileptic encephalopathies (EIDEE; DEE75; MIM #618437) with infantile-onset neurodegeneration. Dilated cardiomyopathy has also been reported in the affected individuals. About 10 individuals to date have been described with pathogenic biallelic variants in PARS2. While many of the reported individuals succumbed to the disease in the first two decades of life, autopsy findings have not yet been reported. Here, we describe neuropathological findings in a deceased male with evidence of intracranial calcifications in the basal ganglia, thalamus, cerebellum, and white matter, similar to Aicardi-Goutières syndrome. This report describes detailed autopsy findings in a child with PARS2-related mitochondrial disease and provides plausible evidence that intracranial calcifications may be a previously unrecognized feature of this disorder.

The discrimination between autoimmune glial fibrillary acidic protein astrocytopathy and tuberculous meningitis.

OBJECTIVE: The differential diagnosis between autoimmune glial fibrillary acidic protein astrocytopathy (AGFAPA) mimicking tuberculous meningitis and tuberculous meningitis (TBM) remains challenging in clinical practice. This study aims to identify the clinical, laboratory parameters, and clinical score systems that may be helpful in differentiating AGFAPA from TBM. METHOD: Overall 22 AGFAPA patients who were initially misdiagnosed as TBM (AGFAPA-TBM) and 30 confirmed TBM patients were included. The clinical, laboratory, imaging parameters, Thwaites systems, and Lancet consensus scoring systems (LCSS) of all patients were reviewed. Logistic regression was employed to establish a diagnostic formula to differentiate AGFAPA-TBM from TBM. The receiver operating characteristic (ROC) curve was applied to determine the best diagnostic critical point of the formula. RESULTS: Urinary retention was more frequent in AGFAPA-TBM patients (72.7% vs 33.3%, p = 0.012). A significantly lower ratio of T-SPOT. TB was noted in AGFAPA-TBM patients (9.1% vs 82.1%, p < 0.001). We found the LCSS was able to differentiate AGFAPA-TBM from TBM (AUC value 0.918, 95% CI=0.897-0.924). Furthermore, we set up a new scoring system with three variables: urinary retention, T-SPOT. TB, and cerebral imaging criteria in LCSS. The proposed diagnostic score ranges from -8 to 2, and a score of ≥ 0 was suggestive of AGFAPA-TBM (AUC value 0.938, 95% CI=0.878-0.951). CONCLUSIONS: This study is the first to evaluate the Thwaites system and LCSS in AGFAPA-TBM and TBM. We provide an alternative diagnostic formula to differentiate AGFAPA-TBM from TBM and suggest testing for GFAP antibodies to avoid misdiagnosis when this scoring system meets AGFAPA-TBM.

General features, pathogenesis, and laboratory diagnostics of autoimmune encephalitis.

Autoimmune encephalitis (AE) is a group of inflammatory conditions that can associate with the presence of antibodies directed to neuronal intracellular, or cell surface antigens. These disorders are increasingly recognized as an important differential diagnosis of infectious encephalitis and of other common neuropsychiatric conditions. Autoantibody diagnostics plays a pivotal role for accurate diagnosis of AE, which is of utmost importance for the prompt recognition and early treatment. Several AE subgroups can be identified, either according to the prominent clinical phenotype, presence of a concomitant tumor, or type of neuronal autoantibody, and recent diagnostic criteria have provided important insights into AE classification. Antibodies to neuronal intracellular antigens typically associate with paraneoplastic neurological syndromes and poor prognosis, whereas antibodies to synaptic/neuronal cell surface antigens characterize many AE subtypes that associate with tumors less frequently, and that are often immunotherapy-responsive. In addition to the general features of AE, we review current knowledge on the pathogenic mechanisms underlying these disorders, focusing mainly on the potential role of neuronal antibodies in the most frequent conditions, and highlight current theories and controversies. Then, we dissect the crucial aspects of the laboratory diagnostics of neuronal antibodies, which represents an actual challenge for both pathologists and neurologists. Indeed, this diagnostics entails technical difficulties, along with particularly interesting novel features and pitfalls. The novelties especially apply to the wide range of assays used, including specific tissue-based and cell-based assays. These assays can be developed in-house, usually in specialized laboratories, or are commercially available. They are widely used in clinical immunology and in clinical chemistry laboratories, with relevant differences in analytic performance. Indeed, several data indicate that in-house assays could perform better than commercial kits, notwithstanding that the former are based on non-standardized protocols. Moreover, they need expertise and laboratory facilities usually unavailable in clinical chemistry laboratories. Together with the data of the literature, we critically evaluate the analytical performance of the in-house vs commercial kit-based approach. Finally, we propose an algorithm aimed at integrating the present strategies of the laboratory diagnostics in AE for the best clinical management of patients with these disorders.

SAMHD1 compound heterozygous rare variants associated with moyamoya and mitral valve disease in the absence of other features of Aicardi-Goutières syndrome.

Aicardi-Goutières syndrome (AGS) is an autosomal recessive inflammatory syndrome that manifests as an early-onset encephalopathy with both neurologic and extraneurologic clinical findings. AGS has been associated with pathogenic variants in nine genes: TREX1, RNASEH2B, RNASEH2C, RNASEH2A, SAMHD1, ADAR, IFIH1, LSM11, and RNU7-1. Diagnosis is established by clinical findings (encephalopathy and acquired microcephaly, intellectual and physical impairments, dystonia, hepatosplenomegaly, sterile pyrexia, and/or chilblains), characteristic abnormalities on cranial CT (calcification of the basal ganglia and white matter) and MRI (leukodystrophic changes), or the identification of pathogenic/likely pathogenic variants in the known genes. One of the genes associated with AGS, SAMHD1, has also been associated with a spectrum of cerebrovascular diseases, including moyamoya disease (MMD). In this report, we describe a 31-year-old male referred to genetics for MMD since childhood who lacked the hallmark features of AGS patients but was found to have compound heterozygous SAMHD1 variants. He later developed mitral valve insufficiency due to recurrent chordal rupture and ultimately underwent a heart transplant at 37 years of age. Thus, these data suggest that SAMHD1 pathogenic variants can cause MMD without typical AGS symptoms and support that SAMHD1 should be assessed in MMD patients even in the absence of AGS features.

Dyschromatosis symmetrica hereditaria: A clue to early diagnosis of Aicardi-Goutières syndrome.

A 6-year-old female with a history of Aicardi-Goutières syndrome (AGS) presented to dermatology clinic with hypopigmented and hyperpigmented macules and patches consistent with dyschromatosis symmetrica hereditaria (DSH). Previous genetic workup demonstrated a de novo, heterozygous mutation in the adenosine deaminase acting on RNA 1 (ADAR) gene. While the co-occurrence of AGS and DSH has previously been described in mutations of the ADAR gene, our case highlights the potential association between these disorders that may aid in earlier future diagnosis of AGS.