Autoimmune glial fibrillary acidic protein astrocytopathy

A case of glial fibrillary acidotic protein (GFAP) meningoencephalitis with rheumatoid arthritis

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is an inflammatory disease of the central nervous system (CNS), which affects various regions in the CNS, presenting by variable clinical manifestations. Meningoencephalitis is the most common clinical presentation and association with autoimmune disorders has been reported in about 20% of these patients. Diagnosis is confirmed by the presence of CSF or serum immunoglobulin-G (IgG) against GFAP. The reported case is a 53-year-old woman with the history of long-standing rheumatoid arthritis who first presented with acute-onset dizziness and gait disturbance, periventricular linear and radial enhancement pattern on MRI, and normal CSF analysis, successfully treated with an increase in the dose of oral steroids. After a year she had a subacute-onset, moderate to severe holocephalic headache, normal neurologic examination and CSF analysis, and bilateral diffuse, pachymeningeal, and leptomeningeal enhancement on MRI. According to her Brain MRI imaging with relapsing remitting course steroid responsive ataxia and aseptic meningitis, her serum was tested for GFAP IgG antibodies which was positive. The reported patient is the first in the literature reported pachymeningitis in GFAP astrocytopathy. This case highlights the co-occurrence of rheumatoid arthritis with GFAP-associated astrocytopathy, and expands on the previously reported cases with similar association. This might also suggest a common immune pathogenesis.

Non-infectious meningitis and CNS demyelinating diseases: A conceptual review

Many cases of aseptic meningitis or meningoencephalitis, unresponsive to antimicrobial treatments, have been reported recently in patients with established/new-onset central nervous system (CNS) inflammatory demyelinating diseases (CNSIDDs). Given the higher probability of infectious etiologies, CNSIDDs are rarely considered among the differentials in meningitis or meningoencephalitis cases. We gathered and tabulated cases of non-infectious, steroid-responsive meningitis or meningoencephalitis associated with neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein-associated disease (MOGAD). This conceptual review highlights the need to bolster routine infectious workups with immunological workups in cases of meningoencephalitis or meningitis where potential autoimmune etiologies can be suspected. Although differentiating CNSIDDs with meningeal involvement from infectious meningitis may not substantially affect acute treatment strategies, long-term management and follow-up of the two are entirely different. We also discuss future research directions and hypotheses on how CNSIDDs may be associated with meningitis-like presentations, e.g. overlapping glial fibrillary acidic protein astrocytopathy or autoimmune encephalitis, alterations in regulatory T-helper cells function, and undetected viral agents.

Imaging of Central Nervous System Autoimmune, Paraneoplastic, and Neuro-rheumatologic Disorders

OBJECTIVE

This article provides an overview of the imaging modalities used in the evaluation of central nervous system (CNS) autoimmune, paraneoplastic, and neuro-rheumatologic disorders. An approach is outlined for interpreting imaging findings in this context, synthesizing a differential diagnosis based on certain imaging patterns, and choosing further imaging for specific diseases.

LATEST DEVELOPMENTS

The rapid discovery of new neuronal and glial autoantibodies has revolutionized the autoimmune neurology field and has elucidated imaging patterns characteristic of certain antibody-associated diseases. Many CNS inflammatory diseases, however, lack a definitive biomarker. Clinicians should recognize neuroimaging patterns suggestive of inflammatory disorders, as well as the limitations of imaging. CT, MRI, and positron emission tomography (PET) modalities all play a role in diagnosing autoimmune, paraneoplastic, and neuro-rheumatologic disorders. Additional imaging modalities such as conventional angiography and ultrasonography can be helpful for further evaluation in select situations.

ESSENTIAL POINTS

Knowledge of imaging modalities, both structural and functional, is critical in identifying CNS inflammatory diseases quickly and can help avoid invasive testing such as brain biopsy in certain clinical scenarios. Recognizing imaging patterns suggestive of CNS inflammatory diseases can also facilitate the early initiation of appropriate treatments to diminish morbidity and future disability.

A case report of autoimmune GFAP astrocytopathy presenting with abnormal heart rate variability and blood pressure variability

BACKGROUND

Autonomic dysfunctions including bladder dysfunction, gastrointestinal dysfunction and orthostasis are common symptoms of autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A); however, cardiac autonomic dysfunction and abnormal circadian rhythm of blood pressure, which can lead to poor prognosis and even sudden cardiac death, has never been reported in A-GFAP-A patient.

CASE PRESENTATION

A 68-year-old male Chinese patient presented to our hospital with headache, fever, progressive disturbance of consciousness, dysuria, and limb weakness. Abnormal heart rate variability and non-dipper circadian rhythm of blood pressure gradually developed during hospitalization, which is rare in A-GFAP-A. He had positive GFAP IgG in cerebrospinal fluid (CSF). Enhanced brian MRI showed uneven enhancement and T2 hyperintense lesions of medulla oblongata; Cervical spine MRI showed T2 hyperintense lesions in medulla oblongata and upper margin of the T2 vertebral body. A contrast-enhanced thoracic spine MRI showed uneven enhancement and T2 hyperintense lesions of T1 to T6 vertebral segments. After treatment with intravenous immunoglobulin and corticosteroids, the patient's symptoms, including autonomic dysfunction, alleviated dramatically. Finally, his heart rate variability and blood pressure variability became normal.

CONCLUSIONS

Our case broadens the spectrum of expected symptoms in A-GFAP- A syndromes as it presented with heart rate variability and blood pressure variability.

[Clinical features of autoimmune glial fibrillary acidic protein astrocytopathy in children: an analysis of 34 cases]

OBJECTIVES

To study the clinical features of children with autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A).

METHODS

A retrospective analysis was performed on the medical data of 34 children with GFAP-A who attended the Department of Neurology, Children's Hospital of Chongqing Medical University, from January 2020 to February 2022. The medical data included clinical manifestations, cerebrospinal fluid features, imaging examination results, treatment, and prognosis.

RESULTS

The median age of onset was 8.4 (range 1.9-14.9) years for the 34 children with GFAP-A. The main clinical manifestations included headache (50%, 17/34), fever (47%, 16/34), visual impairment (47%, 16/34), and disturbance of consciousness (44%, 15/34). Abnormal cerebrospinal fluid results were observed in 19 children (56%, 19/34), among whom 8 children had positive autoantibody. The children with overlap syndrome had significantly higher recurrence rate and rate of use of immunosuppressant than those without overlap syndrome (P<0.05). About 77% (24/31) of the children had good response to immunotherapy, and only 1 child had poor prognosis.

CONCLUSIONS

Children with GFAP-A often have non-specific clinical symptoms and show good response to immunotherapy. Children with overlap syndrome have a high recurrence rate, and early application of immunosuppressants may help to prevent recurrence and alleviate symptoms.

Autoimmune-mediated encephalitis and mimics: A neuroimaging review

Autoimmune encephalitis is a category of autoantibody-mediated neurological disorders that often presents a diagnostic challenge due to its variable clinical and imaging findings. The purpose of this image-based review is to provide an overview of the major subtypes of autoimmune encephalitis and their associated autoantibodies, discuss their characteristic clinical and imaging features, and highlight several disease processes that may mimic imaging findings of autoimmune encephalitis. A literature search on autoimmune encephalitis was performed and publications from neuroradiology, neurology, and nuclear medicine literature were included. Cases from our institutional database that best exemplify major imaging features were presented.

Advances in the Pathogenesis of Auto-antibody-Induced Cerebellar Synaptopathies

The presence of auto-antibodies that target synaptic machinery proteins was documented recently in immune-mediated cerebellar ataxias. The autoantigens include glutamic acid decarboxylase 65 (GAD65), voltage-gated Ca²⁺ channel (VGCC), metabotropic glutamate receptor type 1 (mGluR1), and glutamate receptor delta (GluRdelta). GAD65 is involved in the synthesis, packaging, and release of GABA, whereas the other three play important roles in the induction of long-term depression (LTD). Thus, the auto-antibodies toward these synaptic molecules likely impair fundamental synaptic machineries involved in unique functions of the cerebellum, potentially leading to the development of cerebellar ataxias (CAs). This concept has been substantiated recently by a series of physiological studies. Anti-GAD65 antibody (Ab) acts on the terminals of inhibitory neurons that suppress GABA release, whereas anti-VGCC, anti-mGluR1, and anti-GluR Abs impair LTD induction. Notably, the mechanisms that link synaptic dysfunction with the manifestations of CAs can be explained by disruption of the "internal models." The latter can be divided into three levels. First, since chained inhibitory neurons shape the output signals through the mechanism of disinhibition/inhibition, impairments of GABA release and LTD distort the conversion process from the "internal model" to the output signals. Second, these antibodies impair the induction of synaptic plasticity, rebound potentiation, and LTD, on Purkinje cells, resulting in loss of restoration and compensation of the distorted "internal models." Finally, the cross-talk between glutamate and microglia/astrocytes could involve a positive feedback loop that accelerates excitotoxicity. This mini-review summarizes the pathophysiological mechanisms and aims to establish the basis of "auto-antibody-induced cerebellar synaptopathies."

Clinical, imaging features and outcomes of patients with anti-GFAP antibodies: a retrospective study

Objective

To evaluate and compare the clinical features, imaging, overlapping antibodies, and prognosis of pediatric and adult patients with anti-GFAP antibodies.

Methods

This study included 59 patients with anti-GFAP antibodies (28 females and 31 males) who were admitted between December 2019 and September 2022.

Results

Out of 59 patients, 18 were children (under 18 years old), and 31 were adults. The overall cohort's median age at onset was 32 years old, 7 for children, and 42 for adults. There were 23 (41.1%) patients with prodromic infection, 1 (1.7%) patient with a tumor, 29 (53.7%) patients with other non-neurological autoimmune diseases, and 17 (22.8%) patients with hyponatremia. Fourteen (23.7%) patients had multiple neural autoantibodies, with the AQP4 antibody being the most common. Encephalitis (30.5%) was the most common phenotypic syndrome. Common clinical symptoms included fever (59.3%), headache (47.5%), nausea and vomiting (35.6%), limb weakness (35.6%), and disturbance of consciousness (33.9%). Brain MRI lesions were primarily located in the cortex/subcortex (37.3%), brainstem (27.1%), thalamus (23.7%), and basal ganglia (22.0%). Spinal cord MRI lesions often involved the cervical and thoracic spinal cord. There was no statistically significant difference in the MRI lesion site between children and adults. Out of 58 patients, 47 (81.0%) had a monophasic course, and 4 died. The last follow-up showed that 41/58 (80.7%) patients had an improved functional outcome (mRS <3), and children were more likely than adults to have no residual disability symptoms (p = 0.001).

Conclusion

There was no statistically significant difference in clinical symptoms and imaging findings between children and adult patients with anti-GFAP antibodies; Patients with anti-GFAP antibodies may present with normal MRI findings or delayed MRI abnormalities, and patients with overlapping antibodies were common. Most patients had monophasic courses, and those with overlapping antibodies were more likely to relapse. Children were more likely than adults to have no disability. Finally, we hypothesize that the presence of anti-GFAP antibodies is a non-specific witness of inflammation.

GFAP astrocytopathy presenting with profound intracranial hypertension and vision loss

BACKGROUND

Glial fibrillary acidic protein (GFAP) astrocytopathy is a steroid-responsive autoimmune meningoencephalomyelitis commonly preceded by a viral illness. It is clinically characterized by encephalopathy, myelopathy and papillitis without significant effect on visual acuity. It can be associated with an underlying malignancy or autoimmune condition.

OBJECTIVE

To report a novel case of GFAP astrocytopathy presenting with profound intracranial hypertension and bilateral vision loss.

METHODS

Case report.

RESULTS AND CONCLUSION

GFAP astrocytopathy should be considered when evaluating patients with intracranial hypertension or bilateral vision loss, particularly when other features of autoimmune encephalitis are present.

Clinical Manifestation, Auxiliary Examination Features, and Prognosis of GFAP Autoimmunity: A Chinese Cohort Study

OBJECTIVE

This paper reports the clinical manifestation and auxiliary examination features of 15 Chinese patients with glial fibrillary acidic protein (GFAP) autoimmunity.

METHODS

From June 2016 to December 2019, patients suspected to have neurological autoimmune disease after having their serum and cerebrospinal fluid (CSF) tested for conventional neural antibodies were scanned for additional autoantibodies by immunohistochemistry. Samples that showed a characteristic immunoreactive pattern reminiscent of the GFAP of astrocytes were selected and confirmed by cell-based assay using cells-expressing human GFAPα.

RESULTS

A total of 15 patients (eight male and seven female) with a median age at onset of 53 years (range 28-72) were identified as GFAP-IgG-positive. Fourteen cases had GFAP-IgG detected in the CSF, while serum GFAP-IgG was detected in 11 cases. Eleven of the fifteen patients (73.3%) presented with an acute monophasic course, of which 10 (90.9%) had antecedent flu-like symptoms. The predominant phenotype was meningoencephalitis (46.7%), followed by meningoencephalomyelitis in 40% of the cases. The most common clinical features included long tract signs, brainstem symptoms, tremors, headaches, and psychiatric symptoms. Magnetic resonance imaging (MRI) revealed the enhancement of the meninges, the surface of the brainstem, the cerebellum, and the spinal cord as predominant. Inflammatory CSF showed mild lymphocyte-predominant pleocytosis with a median of 51/μL and elevated protein with a median of 87.5 mg/dL. Five patients had coexisting antibodies, including NMDAR-IgG in three patients and Yo and MOG-IgG in one patient each. One patient underwent a stereotactic brain biopsy, and the neuropathology diagnosis was diffuse large B-cell lymphoma. One patient had ovarian teratoma. Eleven of the fifteen (73.3%) patients received both intravenous immunoglobulin and steroids. Among them, three patients also received immunosuppressive agents later. During a two-year follow-up, 9 of the 15 (60%) patients achieved complete clinical remission.

CONCLUSIONS

The clinical presentation of GFAP astrocytopathy is heterogeneous. It can be characterized by an acute monophasic course and a chronic relapsing course. Tremors are a prominent clinical manifestation in patients with an acute monophasic course with GFAP-IgG antibodies only. Most patients responded well to immunotherapy. In patients with GFAP autoimmunity, presenting with a chronic relapsing course, one should actively search for immunogenic factors and the culprit antibodies. In the case of primary central nervous system lymphoma, GFAP autoimmunity does not always equate to autoimmune GFAP astrocytopathy.

A case of EBV encephalomyelitis with positive anti-GFAP-IgG antibody with recurrent fever and dysuresia as the main symptoms: Case report and retrospective analysis

RATIONALE

Due to neuronal destruction caused by Epstein-Barr virus (EBV) infection, exposure to neuronal surface antigens may lead to an imbalance in immune tolerance, which in turn triggers an autoimmune response. In addition, due to the involvement of nonspecific B-cell activation or molecular mimicry, EBV and Glial Fibrillary Acidic Protein (GFAP) receptors may have common epitopes. Viral infection triggers activation of B-cell and cross-reaction with viral antibodies, resulting in autoimmune encephalomyelitis. The clinical presentation may be complex or even atypical. A small number of patients may develop autoimmune reactions.

PATIENT CONCERNS

Most patients with EBV encephalomyelitis have a good prognosis, with the disease generally having a short course, few complications, and a good prognosis. In most patients, after treatment, their neurological function basically recovers within a few weeks or months.

DIAGNOSIS INTERVENTIONS

The patient had fever and headache. His 3 tests for cerebral spinal fluid (CSF) are consistent with the features of viral encephalomyelitis. Pathogenic examination of CSF confirmed EBV, and imaging suggested brain and spinal cord involvement. After antiviral treatment, the patient's symptoms relieved. The diagnosis of EBV encephalomyelitis was considered. However, the patient's temperature continued to increase. He was transferred to a superior hospital and was given GFAP-Ab in CSF, which was strongly positive. The patient was given immunoglobulin and antiviral therapy. This supports the diagnosis of GFAP-IgG antibody positive with EBV encephalomyelitis.

OUTCOMES

After treatment with antiviral drugs and immunoglobulins, the patient's symptoms improved and he was able to function.

LESSONS

EBV encephalomyelitis is a rare clinical disease. Therefore, more attention should be paid to the early diagnosis and treatment of similar patients to avoid misdiagnosis. CSF tests, genetic tests, and imaging tests can confirm the diagnosis.

Autoimmune glial fibrillar acidic protein astrocytopathy mimicking tuberculous meningitis

Autoimmune glial fibrillar acidic protein (GFAP) astrocytopathy typically presents as acute or subacute meningoencephalitis with or without myelitis. We describe a case of autoimmune GFAP astrocytopathy that mimicked tuberculous meningitis. A man in his 70s was referred to our hospital with lethargy persistent for 2 months, appetite loss for 1 month and fever with headache for 10 days. The cerebrospinal fluid test revealed lymphocytic pleocytosis with elevated adenosine deaminase (ADA). Laboratory investigations ruled out microbial and neoplastic causes. Empirical therapy for tuberculous meningitis combined with corticosteroid improved the patient's condition. Culture for Mycobacterium tuberculosis failed to show microbial growth despite 1 month of incubation. The cerebrospinal fluid was examined for GFAP antibody and returned positive result. Antituberculous agents were discontinued, and corticosteroid was administered until patient's symptoms resolved completely. Thus, clinicians should consider autoimmune GFAP astrocytopathy as one of the differential diagnoses of lymphocytic meningitis with elevated ADA.

Anti-NMDAR encephalitis with GFAPα IgG: a case report

Background

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an inflammatory disease of the central nervous system (CNS) in which antibodies within the serum and cerebrospinal fluid (CSF) target NMDA receptors. Glial fibrillary acidic protein (GFAP) astrocytopathy is an autoimmune disease affecting the central nervous system (CNS). Meningoencephalitis can affect any anatomical region rostrocaudally, from the optic nerve to the spinal cord. The clinical implications of NMDAR antibodies overlapping with other antibodies against glial or neuronal cell surface proteins have not been investigated.

Case presentation

A 35-year-old male presented with headaches along with amnesia, slurred and awkward speech, psychiatric symptoms, cognitive decline, and insomnia. His medical history revealed ankylosing spondylitis for six months. Ancillary findings included CSF pleocytosis and elevated protein levels. T2-weighted fluid attenuation inversion recovery was used to image high-intensity lesions of the bilateral paraventricular, radiate corona, semioval centre, and right subcortical regions. The CSF was positive for NMDAR and GFAP antibodies through transfected cell-based assays. A diagnosis of anti-GFAP encephalitis was made, although the prominent clinical features were of anti-NMDAR encephalitis.

Conclusions

Herein, we describe a case of anti-NMDAR encephalitis with overlapping symptoms of GFAP antibody positivity. Patients with unusual symptoms of anti-NMDAR encephalitis should also be tested for anti-GFAP antibodies. However, because this was a single case study, caution should be exercised when interpreting the observations. Since the patient was diagnosed with autoimmune encephalitis, intravenous methylprednisolone was administered, which yielded a positive outcome.

A pediatric case of autoimmune glial fibrillary acidic protein astrocytopathy with unique brain imaging patterns and increased cytokines/chemokines

BACKGROUND

Autoimmune anti-glial fibrillary acidic protein (GFAP) astrocytopathy represents a new spectrum of autoimmune inflammatory central nervous system disorders. In recent years, there have been an increasing number of reports on pediatric patients with this disease other than those in Japan.

CASE REPORT

A 6-year-old previously healthy boy presented with fever persisting for approximately 10 days, consciousness disturbance, anorexia, and hyponatremia (Na, 121 mEq/L). Even after appropriate correction of hyponatremia, consciousness disturbance was prolonged and was accompanied by gait disturbance, visual hallucinations, and autonomic dysfunction (bradycardia and urinary dysfunction). On a plain MRI, T2-weighted and fluid-attenuated inversion recovery images showed abnormal hyperintense lesions in the bilateral basal ganglia, thalamus, and periventricular white matter. The cerebrospinal fluid was positive for anti-GFAP antibody before treatment, and cytokines/chemokines were increased. He received three courses of intravenous methylprednisolone, followed by gradually tapered oral prednisolone for 6 months, without relapse after 1 year of observation.

CONCLUSION

In cases of autoimmune encephalitis with prolonged consciousness disturbance, hyponatremia, urinary dysfunction, and MRI findings with hyperintensities in the bilateral basal ganglia, thalamus, and periventricular white matter, anti-glial fibrillary acidic protein antibodies should be examined.

Anti-astrocytic autoantibody patterns in the cerebrospinal fluid of patients with depression and psychosis

Autoimmune astrocytopathy associated with anti-GFAP autoantibodies usually manifests with meningoencephalitis. Here, the first patients with isolated psychiatric syndromes and anti-astrocytic autoantibodies are presented. Patient 1 presented with depression, patient 2 with psychosis. Both patients were found to have novel anti-astrocytic autoantibodies ("GFAP-like") in their cerebrospinal fluid (CSF) using indirect-immunofluorescence on unfixed murine brain sections; testing for well-characterized anti-GFAP autoantibodies was negative. In patient 1, astrocytic staining was mainly limited to glia limitans, in patient 2, a widespread astrocytic staining was identified. Only patient 1 showed improvement using glucocorticosteroids. These cases suggest an expansion of the clinical spectrum for autoimmune astrocytopathy.

Repeated Brain Magnetic Resonance Imaging Provides Clues for the Diagnosis of Autoimmune Glial Fibrillary Acid Protein Astrocytopathy

We herein report a 47-year-old man with autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) revealed by periventricular radial linear enhancement on repeated brain magnetic resonance imaging (MRI). He presented with a history of headache and a fever followed by somnolence and worsening of consciousness. On admission (16 days from the onset), although lymphocytic pleocytosis and hypoglycorrhachia in the cerebrospinal fluid (CSF) were noted, initial brain MRI demonstrated non-specific findings. At 30 days from the onset, repeated brain MRI revealed characteristic findings of GFAP-A, and we detected anti-GFAP antibodies in the CSF. Thus, repeated brain MRI provides clues for the diagnosis of GFAP-A.

Rare Etiologies in Immune-Mediated Cerebellar Ataxias: Diagnostic Challenges

The cerebellum is particularly enriched in antigens and represents a vulnerable target to immune attacks. Immune-mediated cerebellar ataxias (IMCAs) have diverse etiologies, such as gluten ataxia (GA), post-infectious cerebellitis (PIC), Miller Fisher syndrome (MFS), paraneoplastic cerebellar degeneration (PCD), opsoclonus myoclonus syndrome (OMS), and anti-GAD ataxia. Apart from these well-established entities, cerebellar ataxia (CA) occurs also in association with autoimmunity against ion channels and related proteins, synaptic adhesion/organizing proteins, transmitter receptors, glial cells, as well as the brainstem antigens. Most of these conditions manifest diverse neurological clinical features, with CAs being one of the main clinical phenotypes. The term primary autoimmune cerebellar ataxia (PACA) refers to ataxic conditions suspected to be autoimmune even in the absence of specific well-characterized pathogenic antibody markers. We review advances in the field of IMCAs and propose a clinical approach for the understanding and diagnosis of IMCAs, focusing on rare etiologies which are likely underdiagnosed. The frontiers of PACA are discussed. The identification of rare immune ataxias is of importance since they are potentially treatable and may lead to a severe clinical syndrome in absence of early therapy.

Spectrum of Novel Anti-Central Nervous System Autoantibodies in the Cerebrospinal Fluid of 119 Patients With Schizophreniform and Affective Disorders

BACKGROUND

Autoimmune psychosis may be caused by well-characterized anti-neuronal autoantibodies, such as those against the NMDA receptor. However, the presence of additional anti-central nervous system (CNS) autoantibodies in these patients has not been systematically assessed.

METHODS

Serum and cerebrospinal fluid (CSF) from patients with schizophreniform and affective syndromes were analyzed for immunoglobulin G anti-CNS autoantibodies using tissue-based assays with indirect immunofluorescence on unfixed murine brain tissue as part of an extended routine clinical practice. After an initial assessment of patients with red flags for autoimmune psychosis (n = 30), tissue-based testing was extended to a routine procedure (n = 89).

RESULTS

Based on the findings from all 119 patients, anti-CNS immunoglobulin G autoantibodies against brain tissue were detected in 18% (n = 22) of patients (serum 9%, CSF 18%) following five principal patterns: 1) against vascular structures, most likely endothelial cells (serum 3%, CSF 8%); 2) against granule cells in the cerebellum and/or hippocampus (serum 4%, CSF 6%); 3) against myelinated fibers (serum 2%, CSF 2%); 4) against cerebellar Purkinje cells (serum 0%, CSF 2%); and 5) against astrocytes (serum 1%, CSF 1%). The patients with novel anti-CNS autoantibodies showed increased albumin quotients (p = .026) and white matter changes (p = .020) more frequently than those who tested negative for autoantibodies.

CONCLUSIONS

The study demonstrates five novel autoantibody-binding patterns on brain tissue of patients with schizophreniform and affective syndromes. CSF yielded positive findings more frequently than serum analysis. The frequency and spectrum of autoantibodies in these patient groups may be broader than previously thought.

Case report: Revealing a special and rare autoimmune GFAP astrocytopathy in the spinal cord succeeding Neurobrucellosis infection

Brucellosis, a zoonosis, can cause an inflammatory response in most organs and continues to be a public health problem in some endemic areas, whereas neurobrucellosis is a morbid form of brucellosis that affects the central nervous system (CNS) with poor prognosis. Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is an autoimmune disease, and there have been no reports of a Brucella infection, leading to GFAP astrocytopathy. We report the case of a patient with a positive and high level of GFAP antibodies in the cerebrospinal fluid (CSF), following a Brucella infection. Although this patient did not show any responsible lesions in the diffusion sequence of the magnetic resonant imaging (MRI) scan, we found an evidence of thoracolumbar (T12) involvement on fluorodeoxyglucose (FDG) positron emission tomography (PET). The symptoms of spinal cord involvement were only partly relieved after initial treatment [doxycycline (0.1 g Bid) and rifampicin (0.6 g Qd) for 6 weeks]; however, they markedly improved after the subsequent immunosuppressive therapy [intravenous methylprednisolone (1,000 mg for 3 days)], followed by a 50% reduction from the preceding dose after 3 days, and subsequently, oral prednisone tablets (60 mg/day) was started, which was then gradually tapered [reduced to 10 mg/day every 1–2 weeks)]. The positive response to immunosuppressive therapy and treatment outcome strongly indicated the presence of an autoimmune neurological disease probably triggered by some infectious factors. Therefore, our findings reveal that a Brucella infection is one of the causes of autoimmune GFAP astrocytopathy, and when this infection is difficult to be identified by regular MRI, FDG PET can be used as a supplementary method for diagnosis and treatment.

Update in autoimmune and paraneoplastic myelopathies: Newly described antigen targets and antibody testing

Myelopathy is an increasingly recognized presentation of many antibody-mediated neuroinflammatory disorders. While specific features of certain autoimmune myelopathies such as aquaporin-4 antibody associated neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein associated disorder (MOGAD) are well-characterized, other less commonly seen antibody-associated myelopathies are not as well-defined. These include but are not limited to, Hu/ANNA1, anti-glial fibrillary acidic protein (GFAP), anti-CV2/collapsin response mediator protein (CRMP5), and amphiphysin. Here, we review the mentioned more common antibody mediated myelopathies as well those that as less common, followed by a review of differentials that may mimic these disorders.

Comparison of clinical and radiological characteristics in autoimmune GFAP astrocytopathy, MOGAD and AQP4-IgG+ NMOSD mimicking intracranial infection as the initial manifestation

OBJECTIVE

Several autoimmune CNS inflammatory diseases, including autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and aquaporin-4-immunoglobulin-G-positive neuromyelitis optica spectrum disorders (AQP4-IgG⁺NMOSD) often presented initially with similar symptoms mimicking intracranial infection, are not easy to be differentiated during early-onset lacking the detection of autoantibody.

METHODS

In our single-center cohorts, those patients mimicking intracranial infection as initial symptoms, including 9 with A-GFAP-A, 17 with MOGAD and 11 with AQP4-IgG⁺NMOSD, were retrospectively included. The autoantibodies were detected by cell-based assays. The clinical, immunological and radiological characteristics were summarized.

RESULTS

In the cohort, tremor and positive Kernig's sign were predominated in A-GFAP-A (44.4% and 77.8%, respectively) over MOGAD (5.9%, p = 0.034; 29.4%, p = 0.038) and AQP4-IgG⁺NMOSD (0, p = 0.026; 18.2%, p = 0.022). Ten patients (A-GFAP-A, 4; MOGAD, 5; AQP4-IgG⁺NMOSD, 1) were initially misdiagnosed as tubercular or viral meningoencephalitis, however, resistant to empiric anti-tuberculosis or anti-viral treatment, and finally were in partial or complete remission with the immunotherapy when adjusted treatments. On cerebrospinal fluid (CSF) examination, white blood cell counts in CSF was higher in A-GFAP-A cohort (median, 90×10⁶/L [IQR, 41-209]) compared to AQP4-IgG⁺ NMOSD (median, 6 × 10⁶/L [IQR, 1-10], p = 0.018). Importantly, the higher increase in CSF protein (1319 mg/L [IQR, 1035-1519]), lactate dehydrogenase (LDH, 53.9 ± 37.2 U/L), lactic acid (3.50 ± 0.88 mmol/L), IgG (130.9 ± 60.4 mg/L), IgM (8.6 ± 6.1 mg/L) and IgA (23.0 ± 11.4 mg/L) levels in A-GFAP-A was found compared to MOGAD (CSF protein: 441 mg/L [IQR, 330-776], p = 0.004; LDH: 53.9  ±  37.2 U/L, p = 0.005; lactic acid: 2.15 ± 0.62 mmol/L, p = 0.001; IgG: 77.9 ± 71.3 mg/L, p = 0.018; IgM, 2.7 ± 2.9 mg/L, p = 0.015) and AQP4-IgG⁺ NMOSD (CSF protein: 386 mg/L [IQR, 369-453], p = 0.002; LDH: 23.7 ± 11.0 U/L, p = 0.048; lactic acid: 2.40  ±  0.66 mmol/L, p = 0.040; IgG, 53.2 ± 30.3 mg/L, p = 0.015; IgM, 2.1 ± 3.9 mg/L, p = 0.004; IgA, 5.2 ± 5.0 mg/L, p < 0.001). Of Note, smaller (< 2 cm), symmetrical lesions in ganglia and thalamus (5/8, 62.5%) were showed in over half of the A-GFAP-A patients (5/8, 62.5%), but never in MOGAD (0%, p = 0.001) and AQP4-IgG⁺NMOSD (0%, p = 0.026). In addition, diffuse meningeal enhancement was more common in A-GFAP-A (8, 88.9%) compared to MOGAD (5, 29.4%, p = 0.011) and AQP4-IgG⁺NMOSD (1/6, 16.7%, p = 0.011), respectively. Acute disseminated encephalomyelitis (ADEM) -like lesions occurred more frequently in MOGAD (6/16, 37.5%) but never in A-GFAP-A and AQP4-IgG⁺NMOSD (p = 0.02).

CONCLUSION

Our study demonstrates that several distinct features including the symptom of tremor, higher CSF immunological profiles, bilateral symmetrical lesions in ganglia, and diffuse meningeal enhancement are frequent in A-GFAP-A, whereas ADEM-like lesions seem to occur mainly in MOGAD. These signs provide crucial clinical implications in differential diagnosis for those mimicking intracranial infection as initial symptoms. Clinicians should consider the possibility of these autoimmune CNS inflammatory diseases masquerading as intracranial infection.

Autoimmune glial fibrillary acidic protein astrocytopathy presented as isolated area postrema symdrome: a case report

Background

Area postrema syndrome (APS) as the isolated manifestation in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy has been rarely reported.

Case presentation

A 61-year-old male patient presented with intractable hiccup. He was first admitted to the department of Gastroenterology because he had no symptoms other than hiccup. Then he was diagnosed with possible digestive system disease and started on treatment. 2 weeks later, his symptom didn’t improve at all. After consultation, the patient was referred to our department. Cerebrospinal fluid (CSF) analysis revealed lymphocytes pleocytosis, elevated protein level. Cell-based assays demonstrated GFAP antibodies in blood and CSF. His symptom improved with steroid pulse therapy (methylprednisolone, 1 g for 5 days), followed by a gradual tapering of oral prednisolone. Three months after the initial presentation, he showed no relapses.

Conclusions

We report atypical manifestation of autoimmune GFAP astrocytopathy which presented as APS, suggesting that autoimmune GFAP astrocytopathy should be added to the list of possible cause of APS.

Hybrid 18F-florbetapir PET/MRI for assessing myelin recovery in GFAP-A patients

Glial fibrillary acidic protein astrocytopathy (GFAP-A) is a rare autoimmune disease of the central nervous system that was newly reported in 2016. Previous studies have speculated that the pathological mechanism and clinical outcome of GFAP-A lie in the demyelination of the central nervous system, but due to the limitations of MR, this conclusion has not been further confirmed from the perspective of neuroimaging. A non-invasive, quantitative measurement of demyelination would be clinically valuable, given its critical role in mediating GFAP-A. Here, we report a case in which we use ¹⁸F-florbetapir positron emission tomography-magnetic resonance imaging (PET/MRI) to evaluate myelin recovery with follow-up in the patient with GFAP-A. Our patient displayed a decreased uptake of PET tracer ¹⁸F-florbetapir in the brain lesions and lower distribution volume ratio in the damaged white matter lesions compared to the normal-appearing white matter, indicating significant intracranial demyelination. After treatment, the ¹⁸F-florbetapir PET/MRI examination showed a significant increase in the uptake of ¹⁸F-florbetapir in the brain lesions, along with a reduced Expanded Disability Status Scale score. Although only a small number of patients have been validated, this case first reported ¹⁸F-florbetapir PET/MRI could quantitatively and non-invasively assess the myelin recovery in GFAP-A patients, which may lead to improvements in the early diagnosis and long-term prognosis.

Ovarian Teratoma-Related Paraneoplastic Neurological Syndromes

Paraneoplastic neurological syndromes (PNSs) are a group of neurological disorders triggered by an underlying remote tumor. Ovarian teratoma (OT) is the most common histologic type of germ cell tumor in females. The most common PNSs associated with OT is anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. However, with the increasing number of new antibodies reported over the last decade, the clinical spectrum of OT-related PNSs is also expanding. Our knowledge of OT-related PNSs is still far from complete. Here, we provide a comprehensive review of the most recent findings in the field of OT-related PNSs, with a particular focus on their clinical and pathological characteristics. Overall, the description of neuronal antibodies in PNSs associated with OT strongly suggests that antibodies may be responsible for the clinical symptoms in some cases. OT-related PNSs are associated with various clinical manifestations, including anti-NMDAR encephalitis, limbic encephalitis, encephalomyelitis, progressive cerebellar syndrome and opsoclonus-myoclonus syndrome. The pathological characteristics of the OT suggest that the mechanism of PNSs is probably due to heteromorphic neurons in the tumor tissue, the ectopic expression of the antigens in neural tissue within the teratomas and patients' unusual immune response. Despite the severity of the neurological syndromes, most patients with OT-related PNSs showed good neurologic response to early tumor resection combined with immunotherapy. To further advance the management of OT-related PNSs, additional studies are needed to explore this complex topic.

Pathomechanisms in demyelination and astrocytopathy: autoantibodies to AQP4, MOG, GFAP, GRP78 and beyond

PURPOSE OF REVIEW

The purpose of this review is to highlight the recently emerging pathomechanisms of diseases associated with autoantibodies to AQP4, MOG, GFAP, GRP78 and further novel targets. We discuss novel biomarkers and therapeutic approaches.

RECENT FINDINGS

Although complement-mediated cytotoxicity (CDC) is regarded as the major effector mechanism for AQP4-IgG in neuromyelitis optica spectrum disorders (NMOSD), recent studies helped to understand the relevance of complement-independent effector mechanisms. For MOG-IgG mediated diseases the role of CDC is less clear. MOG-IgG may trigger a tightly controlled FcR and BTK-driven microglia proliferative response in MOG-antibody-associated diseases. Differences of antibody-mediated tissue damage may reflect differential response to therapy. In addition, antibodies to GFAP, GRP78 and further novel targets have been implicated in demyelination and astrocytopathy.

SUMMARY

Elucidating the whole spectrum of effector functions in diseases mediated by AQP4-IgG and MOG-IgG and understanding the role of additional novel autoantibodies involved in demyelination and astrocytopathy may guide further novel treatment decisions.

[Recurrent autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy with long cervical cord lesions: a case report]

A 61-year-old man who had suffered two episodes of generalized convulsion in a two-year period was admitted to our hospital because of progressive gait disturbance during the previous five months. Neurological examination revealed cognitive impairment, spasticity of the lower limbs, truncal ataxia, and dysautonomia including orthostatic hypotension, dysuria and hypohydrosis. Brain fluid-attenuated inversion recovery (FLAIR) MRI detected high-signal-intensity lesions in the periventricular white matter and centrum semiovale, with punctate gadolinium (Gd) enhancement. Spinal MRI detected swollen cervical long cord lesions extending from C2 to C6. Although methylprednisolone pulse treatment initially ameliorated the symptoms and MRI abnormal findings, clinical symptoms and MRI abnormalities including new cervical lateral column lesions reminiscent of those in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy (GFAP-A) relapsed two months later. At this point, anti-GFAPα antibody was detected in the cerebrospinal fluid. Although the clinical course of GFAP-A has been well reported, the present case showed a chronic refractory course.

Plasma autoantibodies to glial fibrillary acidic protein (GFAP) react with brain areas according to Braak staging of Parkinson's disease

Idiopathic Parkinson's disease (PD) is characterized by a progredient degeneration of the brain, starting at deep subcortical areas such as the dorsal motor nucleus of the glossopharyngeal and vagal nerves (DM) (stage 1), followed by the coeruleus-subcoeruleus complex; (stage 2), the substantia nigra (SN) (stage 3), the anteromedial temporal mesocortex (MC) (stage 4), high-order sensory association areas and prefrontal fields (HC) (stage 5) and finally first-order sensory association areas, premotor areas, as well as primary sensory and motor field (FC) (stage 6). Autoimmunity might play a role in PD pathogenesis. Here we analyzed whether anti-brain autoantibodies differentially recognize different human brain areas and identified autoantigens that correlate with the above-described dissemination of PD pathology in the brain. Brain tissue was obtained from deceased individuals with no history of neurological or psychiatric disease and no neuropathological abnormalities. Tissue homogenates from different brain regions (DM, SN, MC, HC, FC) were subjected to SDS-PAGE and Western blot. Blots were incubated with plasma samples from 30 PD patients and 30 control subjects and stained with anti-IgG antibodies to detect anti-brain autoantibodies. Signals were quantified. Prominent autoantigens were identified by 2D-gel-coupled mass spectrometry sequencing. Anti-brain autoantibodies are frequent and occur both in healthy controls and individuals with PD. Glial fibrillary acidic protein (GFAP) was identified as a prominent autoantigen recognized in all plasma samples. GFAP immunoreactivity was highest in DM areas and lowest in FC areas with no significant differences in anti-GFAP autoantibody titers between healthy controls and individuals with PD. The anti-GFAP autoimmunoreactivity of different brain areas correlates with the dissemination of histopathological neurodegeneration in PD. We hypothesize that GFAP autoantibodies are physiological but might be involved as a cofactor in PD pathogenesis secondary to a leakage of the blood-brain barrier.

Neuroimaging of Epilepsy

PURPOSE OF REVIEW

This article provides an overview of imaging modalities, important imaging pathologies, and the role each imaging modality can play in the diagnosis, evaluation, and treatment of epilepsy, including epilepsy surgery.

RECENT FINDINGS

The Harmonized Neuroimaging of Epilepsy Structural Sequences (HARNESS-MRI) protocol was proposed to standardize MRI imaging for all patients with seizures. The role of 7-Tesla MRI in finding previously occult epileptogenic lesions is under investigation, and the technique is increasingly used. Developing MRI postprocessing techniques can increase the sensitivity of MRI. Improvements in functional imaging techniques such as EEG-functional MRI (fMRI) and magnetic source imaging provide complementary methods of identifying seizure foci. New epileptogenic pathologies such as multinodular and vacuolating neuronal tumors (MVNT) are being discovered, and the importance of others, such as encephaloceles, is better appreciated.

SUMMARY

Brain imaging is a critical component of the diagnosis and evaluation of patients with epilepsy. Structural imaging modalities such as MRI and CT allow for the identification of a wide variety of potentially epileptogenic lesions. For patients with drug-resistant epilepsy under consideration for resective surgery, both structural and functional neuroimaging may be needed for focus identification and surgical planning for preservation of neurologic function.

Anti-GFAP Antibody-Associated Hypertrophic Pachymeningitis

BACKGROUND

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is an inflammatory central nervous system (CNS) disorder that usually presents as steroid responsive encephalitis, meningitis, myelitis, or meningoencephalomyelitis. Hypertrophic pachymeningitis (HP) is an uncommon disorder that causes a localized or diffuse thickening of the dura mater. Depending on the etiology, HP can be idiopathic or secondary to a wide variety of other diseases. There are no reports of autoimmune GFAP astrocytopathy presenting as HP.

METHODS

In this case report, we describe a rare case of pediatric HP possibly associated with anti-GFAP antibody.

RESULTS

A 13-year-old previously healthy girl presented with headache for nearly 8 months with left-sided peripheral facial palsy and left-sided abductor nerve palsy in the second month of course. Magnetic resonance imaging (MRI) of the brain revealed contrast enhancement of hypertrophic dura mater. Anti-GFAPα antibodies were positive in serum and cerebrospinal fluid. The patient improved clinically after steroid treatment with partial resolution of abnormal intracranial MRI lesions.

CONCLUSION

The present study suggests that HP may be one of the clinical phenotypes for autoimmune GFAP astrocytopathy or GFAP antibody is a biomarker for HP.

Mesenchymal Stem Cell-Derived Extracellular Vesicles and Their Therapeutic Use in Central Nervous System Demyelinating Disorders

Autoimmune demyelinating diseases-including multiple sclerosis, neuromyelitis optica spectrum disorder, anti-myelin oligodendrocyte glycoprotein-associated disease, acute disseminated encephalomyelitis, and glial fibrillary acidic protein (GFAP)-associated meningoencephalomyelitis-are a heterogeneous group of diseases even though their common pathology is characterized by neuroinflammation, loss of myelin, and reactive astrogliosis. The lack of safe pharmacological therapies has purported the notion that cell-based treatments could be introduced to cure these patients. Among stem cells, mesenchymal stem cells (MSCs), obtained from various sources, are considered to be the ones with more interesting features in the context of demyelinating disorders, given that their secretome is fully equipped with an array of anti-inflammatory and neuroprotective molecules, such as mRNAs, miRNAs, lipids, and proteins with multiple functions. In this review, we discuss the potential of cell-free therapeutics utilizing MSC secretome-derived extracellular vesicles-and in particular exosomes-in the treatment of autoimmune demyelinating diseases, and provide an outlook for studies of their future applications.

Characteristics of Movement Disorders in Patients with Autoimmune GFAP Astrocytopathy

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy (GFAP-A) is a type of autoimmune corticosteroid-responsive meningoencephalitis that occurs with or without myelitis. Movement disorders have been reported in GFAP-A patients but have not been characterized. In this study, we examined the characteristics of movement disorders in GFAP-A patients. We retrospectively reviewed clinical data from 87 consecutive patients with GFAP-A attending Gifu University Hospital in Japan. We compared the demographics, clinical features, cerebrospinal fluid characteristics, and neuroimaging findings from patients with and without movement disorders. Seventy-four patients (85%) had movement disorders, including ataxia (49%), tremor (45%), myoclonus (37%), dyskinesia (2%), opsoclonus (2%), rigidity (2%), myokymia (1%), and choreoathetosis (1%). GFAP-A patients with movement disorders were significantly older than those without. Movement disorders are therefore common in GFAP-A patients, and the main types of movement disorders observed in this population were ataxia, tremor, and myoclonus. These abnormal movements can serve as clinical features that facilitate the early diagnosis of GFAP-A. Elderly GFAP-A patients are more likely to have movement disorder complications than younger patients.

Coexistent anti-GFAP and anti-MOG antibodies presenting with isolated meningitis and papillitis: more support for overlapping pathophysiology

Background

Anti-myelin oligodendrocyte glycoprotein (MOG)-associated disorders are heterogeneous and associated predominantly with central nervous system demyelination. Anti-glial fibrillar acidic protein (GFAP) conditions are much rarer and involve meningoencephalomyelitis with papillitis in addition to characteristic imaging findings and are generally a severe condition. Multiple autoantibodies can exist in patients and may support overlapping pathophysiological mechanisms. The co-occurrence of MOG and GFAP antibodies, however, is rare, with only two cases previously reported.

Case

A 53-year-old man presented with headache and fevers, with quick resolution, though with the later development of asymptomatic papillitis. He had a full recovery without the need for immunotherapy. He underwent extensive investigations and was found to have both anti-GFAP and anti-MOG antibodies in the cerebrospinal fluid. Extensive other immunological and infectious investigations were negative. Imaging was largely unremarkable.

Conclusions

This is the third case of overlapping anti-GFAP and anti-MOG antibody-associated syndrome of self-limited lymphocytic meningitis, serving to expand the phenotype. Clinicians should consider testing for GFAP and MOG antibodies in otherwise unexplained meningitis, particularly with associated papillitis. This case may also help provide future insights into the pathophysiology of each condition.

Rapidly progressive dementia: Extending the spectrum of GFAP-astrocytopathies?

Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) is a steroid-responsive meningoencephalomyelitis, sometimes presenting with atypical clinical signs such as movement disorders or psychiatric and autonomic features. Beyond clinical presentation and imaging, diagnosis relies on detection of GFAP-antibodies (AB) in CSF. Using quantitative behavioral, serologic, and immunohistochemical analyses, we characterize two patients longitudinally over 18-24 months who presented with rapidly progressive neurocognitive deterioration in the context of GFAP-AB in CSF and unremarkable cranial MRI studies. Intensified immunotherapy was associated with clinical stabilization. The value of GFAP-AB screening in selected cases of rapidly progressive dementias is discussed.

Case Report: Need for Caution in the Diagnosis of GFAP Astrocytopathy—A Case of GFAP Astrocytopathy Coexistent With Primary Central Nervous System Lymphoma

We reported a case of primary central nervous system lymphoma (PCNSL) coexistent with glial fibrillary acidic protein (GFAP) astrocytopathy, and discussed the problems needing attention in the diagnosis and differential diagnosis of GFAP astrocytopathy. Our patient was a 51-year-old female who presented with somnolence for a month, and memory declination for 10 days. Brain magnetic resonance imaging (MRI) demonstrated multiple abnormal enhancement lesions in bilateral basal ganglia and around the third ventricle, as well as transient T2-weighted hyper-intensity lesions at the splenium of the corpus callosum during the course of the disease. The cerebrospinal fluid (CSF) was positive for anti-GFAP antibodies by antigen-transfected HEK293 cell-based assay (indirect immunofluorescence assay). She was initially diagnosed with autoimmune GFAP astrocytopathy. After treatment with corticosteroids for about 2 months, she displayed poor response and even worsened clinical manifestations when the dose of prednisone reduced to 45 mg. Stereotactic brain biopsy was adopted and the diagnosis of large B-cell lymphoma, non-germinal center type was established on pathological examination. The results of brain biopsy also showed perivascular inflammation and CD8+ T cell infiltration, which also accorded with GFAP astrocytopathy. After chemotherapy with rituximab and methotrexate, the patient showed clinical and radiological improvement significantly. Our findings suggest that positivity of GFAP antibody calls for cautious interpretation. Cancer screening appropriate for age, sex, and risk factors is recommended for GFAP antibody-positive patients, especially for patients with atypical clinical and radiologic manifestations.

Autoimmune glial fibrillary acidic protein astrocytopathy in children: a retrospective study

Objective

To describe the clinical features of autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy in children.

Method

Data from 11 pediatric patients with autoimmune GFAP astrocytopathy were retrospectively analyzed.

Results

All of the patients showed encephalitis and meningoencephalitis or meningoencephalomyelitis with or without myelitis. 45.4% of the patients had fever, 27.3% headaches, 18.2% dizziness, 18.2% drowsiness, and 18.2% mental disorders. Cerebrospinal fluid (CSF) was detected in all patients. The white blood cell counts (WBC) (90.9%), lactic dehydrogenase levels (72.7%), protein level (36.4%), and adenosine deaminase activity (ADA) level (27.3%) were elevated, and the CSF glucose levels (72.7%) were slightly reduced. Nine patients (90%) were found to have brain abnormalities, of which five (50.0%) patients had abnormal symmetrical laminar patterns or line patterns hyperintensity lesions on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images in the basal ganglia, hypothalamus, subcortical white matter and periventricular white matter. The linear radial enhancement pattern of the cerebral white matter was only seen in two patients, with the most common being abnormal enhancement of leptomeninges (50%). Five patients had longitudinally extensive spinal cord lesions.

Conclusion

The findings of pediatric patients with autoimmune GFAP astrocytopathy are different from previous reports.

Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy Associated With Area Postrema Syndrome: A Case Report

Glial fibrillary acidic protein astrocytopathy is an immunotherapy-responsive autoimmune disease of the central nervous system with various clinical manifestations; among these, there are few reports about area postrema syndrome (APS). The authors present the case of a female patient admitted to the hospital with intractable nausea and vomiting as the predominant symptom. The patient's cerebrospinal fluid was tested by cell-based assays (CBA) and found positive for the presence of anti-glial fibrillary acidic protein (GFAP) antibody, in addition, serological testing showed elevated levels of thyroglobulin and thyroperoxidase-specific antibodies. Brain and cervical MRI showed abnormally high signal on the T2 sequence in the dorsal medulla oblongata and right pontine arm. Therefore, the patient was diagnosed with autoimmune GFAP astrocytopathy. The symptoms improved rapidly after treatment with corticosteroids, and no recurrence has been observed thus far. APS may be a relatively rare clinical manifestation of GFAP astrocytopathy. Importantly, such presentation is challenging to correctly diagnose without typical MRI imaging findings. However, the detection of antibodies in the cerebrospinal fluid or serum may be valuable. Systemic and neurological autoimmunity often coexist, comprehensive antibody screening should be conducted.

Autoimmune glial fibrillary acidic protein astrocytopathy resembling isolated central nervous system lymphomatoid granulomatosis

We report two patients with meningoencephalomyelitis without evidence of extra central nervous system (CNS) involvement. Brain MRI showed linear perivascular radial gadolinium enhancement patterns and spinal cord MRI showed longitudinal extensive T2-hyperintensity lesions. Pathological findings from brain biopsies were angiocentric T-cell predominant lymphoid infiltrates that lacked Epstein-Barr virus-positive atypical B cells. The patients were initially suspected to have isolated CNS-lymphomatoid granulomatosis (LYG). Thereafter, glial fibrillary acidic protein (GFAP)-immunoglobulin G were detected in their cerebrospinal fluid. This finding suggested autoimmune GFAP astrocytopathy. We speculate there is a link between isolated CNS-LYG and autoimmune GFAP astrocytopathy.

Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy in Children: A Retrospective Analysis of 35 Cases

Objective

To analyze the clinical manifestations, imaging, electroencephalography, treatment, and prognosis of 35 cases of autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) in children.

Methods

Children hospitalized in the Department of Neurology, Hunan Children’s Hospital, China, between January 2015 and June 2021, owing to autoimmune diseases of the central nervous system were subjected to a cell-based assay (CBA). The assay identified 40 children positive for GFAP-immunoglobulin (Ig)G antibodies in the serum and/or the cerebrospinal fluid. Based on clinical manifestations and imaging characteristics, five children who were only positive for GFAP-IgG antibodies in serum were excluded, and the remaining 35 children were diagnosed with autoimmune GFAP-A. The clinical data derived from the 35 children were retrospectively analyzed.

Results

A total of 35 children, including 23 males and 12 females with a mean age of 6.3 ± 0.6 years, manifested clinical symptoms of fever (62.9%), headache (42.9%), convulsions (42.9%), abnormal mental behavior (51.4%), disorders of consciousness (54.3%), visual disturbance (22.9%), ataxia (11.4%), paralysis (40%), and autonomic dysfunction (25.7%). One child exhibited only the clinical symptom of peripheral facial nerve palsy. Eleven out of 35 children were also positive for other antibodies. In addition to the common overlapping autoimmune syndromes, one case of autoimmune GFAP-A also manifested as Bickerstaff’s brainstem encephalitis. Linear periventricular enhancement upon MRI was significantly less frequent in children (8.5%) than in adults. In pediatric patients, MRI contrast enhancement was principally seen in the meninges and brain lobes. Although repeated relapse (17.1%) and sequelae symptoms (20%) occurred in some cases, most children showed a favorable prognosis. Spearman’s rank correlation showed that the antibody titer was not significantly associated with the severity of the initial disease conditions.

Conclusions

The disease diagnosis in children seropositive for GFAP antibodies only should receive a comprehensive diagnosis based on their clinical symptoms, imaging, electroencephalographic characteristics, and treatment responses. Some patients with relapses should receive repeated gamma globulin and corticosteroid therapy or the addition of immunosuppressants to their therapeutic regimen, and slow-dose tapering of corticosteroids and extended treatment are recommended for patients with overlapping autoimmune syndromes.

Glial Fibrillary Acidic Protein (GFAP) Astrocytopathy Presenting as Mild Encephalopathy with Reversible Splenium Lesion

Introduction

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is scarce and usually presents as meningoencephalomyelitis. Here, we offer the case of an atypical presentation of GFAP-astrocytopathy.

Case Presentation

We report the case of a 26-year-old woman admitted to our neurology department for a 3-week progressive and worsening neurologic picture, with secondary worsening. Initial imaging showed a Mild Encephalitis with Reversible Splenium of corpus callosum lesion (MERS). Full infectious and autoimmune workup then revealed positivity of GFAP antibodies, leading us to diagnose GFAP astrocytopathy.

Discussion

Our case is the first reported association between MERS and GFAP astrocytopathy in an adult patient. Clinical presentation of GFAP astrocytopathy usually includes various neurologic symptoms and can lead to misdiagnosis.

Clinical, neuroradiological, diagnostic and prognostic profile of autoimmune glial fibrillary acidic protein astrocytopathy: A pooled analysis of 324 cases from published data and a single-center retrospective study

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a recently defined autoimmune meningoencephalomyelitis, associated with GFAP-IgG antibody. A pooled analysis of 324 cases from published literature and a retrospective single-center study were performed, firstly reveals the possibility that patients with myelitic lesions respond better to initial immunotherapy, but are prone to relapse, suggesting a more aggressive and long-term immunosuppressive medication for them. Moreover, our results showed using tacrolimus at maintenance stage exhibited a less tendency to relapse, providing a possibly new choice to future clinical treatments.

Autoimmune glial fibrillary acidic protein astrocytopathy presented as ataxia, myoclonus and bulbar syndrome: a case report and review of the literature

Objective

To describe an atypical case of autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy.

Results

A patient in his 60s presented with 6 months of progressive ataxia, proximal myoclonus and bulbar symptomatology. Cerebrospinal fluid (CSF) analysis showed monocytic pleocytosis, elevated protein level and elevated adenosine deaminase (ADA) level. CSF microbiological studies were negative and brain and cervical MRI showed no significant findings. We tested for nuclear, cytoplasmatic and synaptic neural autoantibodies as well as anti-GFAP antibodies. While awaiting these results, the patient was commenced on methylprednisolone boluses (1 g/day for 5 days), noting rapid neurological improvement. Eventually, CSF tests were positive for anti-GFAP antibodies.

Conclusion

We report atypical manifestations of GFAP astrocytopathy. Further research is needed to fully understand the spectrum of neurological manifestations of this autoimmune disease and facilitate timely diagnosis.

Subacute Blindness Revealing an Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is an autoimmune disease of the central nervous system characterized by positive GFAP autoantibody. The most common are encephalitis, meningoencephalitis or meningoencephalomyelitis. Antibodies in cerebrospinal fluid (CSF) against GFAP are biomarkers and expressed in most cases with autoimmune GFAP astrocytopathy. Diagnosis by biopsy is not common practice and has been rarely performed in the literature. This is the particularity of our reported case of autoimmune GFAP astrocytopathy presented as opticopyramidal syndrome, all paraclinical investigations were normal, only the biopsy allowed the diagnosis.

The Association of Ovarian Teratoma and Anti-N-Methyl-D-Aspartate Receptor Encephalitis: An Updated Integrative Review

Ovarian teratomas are by far the most common ovarian germ cell tumor. Most teratomas are benign unless a somatic transformation occurs. The designation of teratoma refers to a neoplasm that differentiates toward somatic-type cell populations. Recent research shows a striking association between ovarian teratomas and anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, a rare and understudied paraneoplastic neurological syndrome (PNS). Among teratomas, mature teratomas are thought to have a greater relevance with those neurological impairments. PNS is described as a neurologic deficit triggered by an underlying remote tumor, whereas anti-NMDAR encephalitis is characterized by a complex neuropsychiatric syndrome and the presence of autoantibodies in cerebral spinal fluid against the GluN1 subunit of the NMDAR. This review aims to summarize recent reports on the association between anti-NMDAR encephalitis and ovarian teratoma. In particular, the molecular pathway of pathogenesis and the updated mechanism and disease models would be discussed. We hope to provide an in-depth review of this issue and, therefore, to better understand its epidemiology, diagnostic approach, and treatment strategies.

Glial fibrillary acidic protein (GFAP)-antibody in children with focal seizures of undetermined cause

Anti-neuronal antibodies that are related with autoimmune encephalitis syndromes may also be found in children with new onset seizures or chronic epilepsy. To unravel the significance of autoimmune astrocytopathy in epilepsy, we investigated serum antibody to glial fibrillary acidic protein (GFAP), another autoantigen described in autoimmune encephalitis with seizures, in 38 children with focal seizures of undetermined cause. GFAP antibody was screened with cell based assay and indirect immunohistochemistry and was found in two boys with normal brain MRI and unrevealing medical history prior to seizures. The 2-year-old boy had chronic treatment-resistant frontal lobe epilepsy. The 2.5-year-old boy had a single episode of focal seizures and remained seizure free thereafter in a follow-up period of 4 years. Nevertheless, he showed severe cognitive and language impairment. These results suggest that autoimmune astrocytopathy may be present in some epilepsy patients. Whether this immune response is a bystander effect generated by seizure-induced astrocytosis or directly involved in epileptogenesis needs to be further studied.

Retinal optical coherence tomography and magnetic resonance imaging in neuromyelitis optica spectrum disorders and MOG-antibody associated disorders: an updated review

INTRODUCTION

Neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein IgG antibody-associated disorders (MOGAD) comprise two groups of rare neuroinflammatory diseases that cause attack-related damage to the central nervous system (CNS). Clinical attacks are often characterized by optic neuritis, transverse myelitis, and to a lesser extent, brainstem encephalitis/area postrema syndrome. Retinal optical coherence tomography (OCT) is a non-invasive technique that allows for in vivo thickness quantification of the retinal layers. Apart from OCT, magnetic resonance imaging (MRI) plays an increasingly important role in NMOSD and MOGAD diagnosis based on the current international diagnostic criteria. Retinal OCT and brain/spinal cord/optic nerve MRI can help to distinguish NMOSD and MOGAD from other neuroinflammatory diseases, particularly from multiple sclerosis, and to monitor disease-associated CNS-damage.

AREAS COVERED

This article summarizes the current status of imaging research in NMOSD and MOGAD, and reviews the clinical relevance of OCT, MRI and other relevant imaging techniques for differential diagnosis, screening and monitoring of the disease course.

EXPERT OPINION

Retinal OCT and MRI can visualize and quantify CNS damage in vivo, improving our understanding of NMOSD and MOGAD pathology. Further efforts on the standardization of these imaging techniques are essential for implementation into clinical practice and as outcome parameters in clinical trials.