Autoimmune GFAP astrocytopathy: Prospective evaluation of 90 patients in 1 year

Clinical and neuroimaging phenotypes of autoimmune glial fibrillary acidic protein astrocytopathy: A systematic review and meta-analysis

OBJECTIVE

This study was undertaken to provide a comprehensive review of neuroimaging characteristics and corresponding clinical phenotypes of autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A), a rare but severe neuroinflammatory disorder, to facilitate early diagnosis and appropriate treatment.

METHODS

A PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis)-conforming systematic review and meta-analysis was performed on all available data from January 2016 to June 2023. Clinical and neuroimaging phenotypes were extracted for both adult and paediatric forms.

RESULTS

A total of 93 studies with 681 cases (55% males; median age = 46, range = 1-103 years) were included. Of these, 13 studies with a total of 535 cases were eligible for the meta-analysis. Clinically, GFAP-A was often preceded by a viral prodromal state (45% of cases) and manifested as meningitis, encephalitis, and/or myelitis. The most common symptoms were headache, fever, and movement disturbances. Coexisting autoantibodies (45%) and neoplasms (18%) were relatively frequent. Corticosteroid treatment resulted in partial/complete remission in a majority of cases (83%). Neuroimaging often revealed T2/fluid-attenuated inversion recovery (FLAIR) hyperintensities (74%) as well as perivascular (45%) and/or leptomeningeal (30%) enhancement. Spinal cord abnormalities were also frequent (49%), most commonly manifesting as longitudinally extensive myelitis. There were 88 paediatric cases; they had less prominent neuroimaging findings with lower frequencies of both T2/FLAIR hyperintensities (38%) and contrast enhancement (19%).

CONCLUSIONS

This systematic review and meta-analysis provide high-level evidence for clinical and imaging phenotypes of GFAP-A, which will benefit the identification and clinical workup of suspected cases. Differential diagnostic cues to distinguish GFAP-A from common clinical and imaging mimics are provided as well as suitable magnetic resonance imaging protocol recommendations.

[Peripheral neuropathy associated with severe glial fibrillary acidic protein (GFAP) astrocytopathy: a case report]

A 44-year-old man was admitted due to a fever. He developed unconsciousness and respiratory failure, necessitating mechanical ventilation. After the administration of methylprednisolone and intravenous immunoglobulin for suspected autoimmune encephalitis, his consciousness and respiratory state improved. However, he exhibited pronounced tetraparalysis and impaired sensation below the neck. A spinal MRI revealed swelling of the entire spinal cord, indicating myelitis. Deep tendon reflexes were diminished in all extremities, and a nerve conduction study confirmed motor-dominant axonal polyneuropathy. Subsequently, he developed a fever and headache. Brain MRI demonstrated FLAIR hyperintensities in the basal ganglia and brain stem. CSF analysis for anti-glial fibrillary acidic protein (GFAP) antibody turned out positive, leading to the diagnosis of GFAP astrocytopathy. Although the steroid re-administration improved muscle strength in his upper limbs and reduced the range of diminished sensation, severe hemiparalysis remained. Severe GFAP astrocytopathy can be involved with polyneuropathy. Early detection and therapeutic intervention for this condition may lead to a better prognosis.

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.

Case report: Headache as the sole neurological symptom in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a recently emerging autoimmune disease of the central nervous system (CNS); GFAP astrocytopathy is characterized by optic neuritis and meningoencephalomyelitis. We report the case of a 55-year-old man, otherwise healthy, who presented with isolated headaches for three months, without other features of meningoencephalitis or myelitis. His neurological examination and fundoscopy were unremarkable. Gadolinium-enhanced brain MRI demonstrated increased T2 hyperintensity within the right sub-lenticular basal ganglia, with additional leptomeningeal enhancement along the bilateral perisylvian regions and mesial temporal lobes. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis, elevated protein, matching oligoclonal bands, and a negative infectious and cytological workup. Cell-based assays for anti-aquaporin-4, anti-myelin oligodendrocyte glycoprotein, autoimmune encephalitis panel, and vasculitis workup were all negative, except for CSF positivity for GFAP α antibody. Oncological screening, including CT of the chest, abdomen, pelvis, and scrotal US, was unremarkable. Immunotherapy with high-dose intravenous steroids for five days and subsequent single four-weekly doses resulted in the resolution of both clinical and radiographic features, with a maintained status 24 months after onset. This case highlights isolated headache and basal ganglia, mesial temporal lobe involvement as a rare presentation of autoimmune GFAP astrocytopathy.

Case report: Atypical case of autoimmune glial fibrillary acidic protein astrocytopathy following COVID-19 vaccination refractory to immunosuppressive treatments

A 54-year-old Japanese man presented with headache and fever the day after SARS-CoV-2 vaccination. He became deeply unconscious within a week. Brain MRI showed periventricular linear enhancements and a few spotty lesions in the cerebral white matter. Cerebrospinal fluid (CSF) testing showed mild pleocytosis. He was treated with intravenous methylprednisolone and plasma exchange. However, the white matter lesions enlarged to involve the brainstem and cerebellum, and long cord spinal lesions appeared. Anti-glial fibrillary acidic protein (GFAP) antibody was positive in the CSF and serum, and he was therefore diagnosed as autoimmune GFAP-astrocytopathy (GFAP-A). In addition, high-dose immunoglobulin therapy was administered twice, but his symptoms did not improve; the white matter lesions enlarged further, and modified Rankin Scale score increased to 5. A brain biopsy specimen showed infiltration of macrophages and CD4 + lymphocytes together with neuron and oligodendrocytic injuries and glial scar. Although GFAP-A generally responds well to steroids, the present case developed GFAP-A following SARS-CoV-2 vaccination, with refractory to intensive immunosuppressive therapy and atypical pathologic findings of infiltration of CD4 + lymphocytes and demyelination.

Clinical characteristics and MRI features of autoimmune glial fibrillary acidic protein astrocytopathy: a case series of 34 patients

Objectives

To analyze the clinical and imaging characteristics of autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A).

Methods

Forty-three patients diagnosed with GFAP-A between March 2017 and July 2023 were retrospectively recruited. The clinical characteristics and magnetic resonance imaging (MRI) features were collected.

Results

Twenty-one patients (61.8%) had a fever and 16 (47.1%) had a headache. Five patients (14.7%) had coexisting neural autoantibodies and one patient (2.9%) had a coexisting neoplasm. The most common presentation was meningoencephalomyelitis (13/34, 38.3%), followed by meningoencephalitis (12/34, 35.3%). The other clinical manifestations included blurred visions (5/34, 14.7%) and peripheral nervous system involvement (4/34, 11.8%). Twenty-six patients (76.5%) had elevated nucleated cell count, predominantly lymphocytes (15/15, 100%), and 27 (79.4%) had elevated protein levels of cerebrospinal fluid. One-half (50%) of the patients presented with hyponatremia. A majority of the patients (30/33, 90.9%) exhibited abnormal hyperintense lesions on T2WI, which were often located in juxtacortical white matter (18/33, 54.5%), followed by periventricular white matter (16/33, 48.5%), basal ganglia (15/ 33, 45.5%), brainstem (11/33, 33.3%), and thalamic lesions (9/33, 27.3%). Twenty-four patients (72.7%) had abnormal brain enhancement, with supratentorial leptomeningeal enhancement being the most frequent enhancement pattern (15/33, 45.5%), followed by linear perivascular radial enhancement (14/33, 42.4%). Nineteen patients (70.4%) had hyperintense intramedullary spinal cord lesions, with long segments (15/27, 55.6%) and transverse lesions (14/27, 51.9%) being the most frequent lesions. Most cases were sensitive to immunotherapy, such as glucocorticoids, intravenous immunoglobulin, and tacrolimus, with three patients (8.8%) experiencing relapses. Patients with brainstem lesions had higher onset modified Rankin scale scores and were more prone to intensive care unit admissions. Linear perivascular radial enhancement was positively associated with poor prognosis (p < 0.05).

Conclusion

GFAP-A presented with meningoencephalomyelitis and meningoencephalitis. The brain lesions were often located in juxtacortical white matter, periventricular white matter, basal ganglia, brainstem, and thalamus. Long segments and transverse were the most frequent spine lesions. Leptomeningeal enhancement was the most frequent enhancement pattern, followed by linear perivascular radial enhancement, which may provide new insight into the differential diagnosis of GFAP-A.

Glial fibrillary acidic protein astrocytopathy presented as meningitis: A case report

Introduction

Glial fibrillary acidic protein (GFAP) astrocytopathy is a novel autoimmune neurological disorder and is diagnosed by GFAP-IgG in cerebrospinal fluid (CSF) measurement.

Case report

Herein, we described a 10-year-old boy with abnormal neurological symptoms and signs. GFAP-IgG was detected in CSF using cell-based assay (CBA), and his CSF showed an increase in lymphocytes, a slight decrease in glucose and an increase in protein level in the early stage. The cranial MRI showed multiple strips of T2-FLAIR hyperintense signal changes on the surface of medulla oblongata, pons, and gyrus in bilateral cerebral hemispheres. He was treated with immunoglobulin (IVIG) and high-dose methylprednisolone pulse treatment, and his clinical presentations gradually improved.

Conclusion

We highlight that patients with normal inflammatory markers in peripheral blood have obvious meningitis-like symptoms, and clinicians need to consider GFAP astrocytopathy. The early diagnosis and treatment of GFAP astrocytopathy are important for improving the prognosis.

KCNA2 IgG autoimmunity in neuropsychiatric diseases

BACKGROUND

Autoantibodies against the potassium voltage-gated channel subfamily A member 2 (KCNA2) have been described in a few cases of neuropsychiatric disorders, but their diagnostic and pathophysiological role is currently unknown, imposing challenges to medical practice.

DESIGN / METHODS

We retrospectively collected comprehensive clinical and paraclinical data of 35 patients with KCNA2 IgG autoantibodies detected in cell-based and tissue-based assays. Patients' sera and cerebrospinal fluid (CSF) were used for characterization of the antigen, clinical-serological correlations, and determination of IgG subclasses.

RESULTS

KCNA2 autoantibody-positive patients (n = 35, median age at disease onset of 65 years, range of 16-83 years, 74 % male) mostly presented with cognitive impairment and/or epileptic seizures but also ataxia, gait disorder and personality changes. Serum autoantibodies belonged to IgG3 and IgG1 subclasses and titers ranged from 1:32 to 1:10,000. KCNA2 IgG was found in the CSF of 8/21 (38 %) patients and in the serum of 4/96 (4.2 %) healthy blood donors. KCNA2 autoantibodies bound to characteristic anatomical areas in the cerebellum and hippocampus of mammalian brain and juxtaparanodal regions of peripheral nerves but reacted exclusively with intracellular epitopes. A subset of four KCNA2 autoantibody-positive patients responded markedly to immunotherapy alongside with conversion to seronegativity, in particular those presenting an autoimmune encephalitis phenotype and receiving early immunotherapy. An available brain biopsy showed strong immune cell invasion. KCNA2 autoantibodies occurred in less than 10 % in association with an underlying tumor.

CONCLUSION

Our data suggest that KCNA2 autoimmunity is clinically heterogeneous. Future studies should determine whether KCNA2 autoantibodies are directly pathogenic or develop secondarily. Early immunotherapy should be considered, in particular if autoantibodies occur in CSF or if clinical or diagnostic findings suggest ongoing inflammation. Suspicious clinical phenotypes include autoimmune encephalitis, atypical dementia, new-onset epilepsy and unexplained epileptic seizures.

[Clinical features and pathogenesis of Glial fibrillary acidic protein (GFAP) antibody-associated disorders]

Glial fibrillary acidic protein (GFAP) antibody-associated disorders (AD) were recently proposed to be immune-mediated neurological disorders. The pathogenesis of GFAP antibody-AD is poorly understood. Pathologically, there is a marked infiltration of large numbers of lymphocytes, including CD8+ and CD4+ T cells, into the meningeal and brain parenchyma, especially around the perivascular areas. GFAP-specific cytotoxic T cells are considered to be the effector cells of GFAP antibody-AD. The common phenotype of GFAP antibody-AD includes meningoencephalitis with or without myelitis. During the clinical disease course, patients present with consciousness disturbances, urinary dysfunction, movement disorders, meningeal irritation, and cognitive dysfunction. The detection of GFAP antibodies in the cerebrospinal fluid (CSF) by cell-based assay is essential for a diagnosis of GFAP antibody-AD. The CSF can be examined for lymphocyte-predominant pleocytosis and elevated protein levels. Brain linear perivascular radial enhancement patterns are observed in about half of GFAP antibody-AD patients. Spinal cord magnetic resonance imaging is used to detect longitudinal extensive spinal cord lesions. Although corticosteroid therapy is generally effective, some patients have a poor prognosis and relapse.

New insights into neuropathology and pathogenesis of autoimmune glial fibrillary acidic protein meningoencephalomyelitis

Anti-glial fibrillary acidic protein (GFAP) meningoencephalomyelitis (autoimmune GFAP astrocytopathy) is a new autoimmune central nervous system (CNS) disease diagnosable by the presence of anti-GFAP autoantibodies in the cerebrospinal fluid and presents as meningoencephalomyelitis in the majority of patients. Only few neuropathological reports are available and little is known about the pathogenic mechanisms. We performed a histopathological study of two autopsies and nine CNS biopsies of patients with anti-GFAP autoantibodies and found predominantly a lymphocytic and in one autopsy case a granulomatous inflammatory phenotype. Inflammatory infiltrates were composed of B and T cells, including tissue-resident memory T cells. Although obvious astrocytic damage was absent in the GFAP-staining, we found cytotoxic T cell-mediated reactions reflected by the presence of CD8+/perforin+/granzyme A/B+ cells, polarized towards astrocytes. MHC-class-I was upregulated in reactive astrocytes of all biopsies and two autopsies but not in healthy controls. Importantly, we observed a prominent immunoreactivity of astrocytes with the complement factor C4d. Finally, we provided insight into an early phase of GFAP autoimmunity in an autopsy of a pug dog encephalitis that was characterized by marked meningoencephalitis with selective astrocytic damage with loss of GFAP and AQP4 in the lesions.Our histopathological findings indicate that a cytotoxic T cell-mediated immune reaction is present in GFAP autoimmunity. Complement C4d deposition on astrocytes could either represent the cause or consequence of astrocytic reactivity. Selective astrocytic damage is prominent in the early phase of GFAP autoimmunity in a canine autopsy case, but mild or absent in subacute and chronic stages in human disease, probably due to the high regeneration potential of astrocytes. The lymphocytic and granulomatous phenotypes might reflect different stages of lesion development or patient-specific modifications of the immune response. Future studies will be necessary to investigate possible implications of pathological subtypes for clinical disease course and therapeutic strategies.

Paraneoplastic movement disorders

Paraneoplastic movement disorders are diverse autoimmune neurological illnesses occurring in the context of systemic cancer, either in isolation or as part of a multifocal neurological disease. Movement phenomena may be ataxic, hypokinetic (parkinsonian), or hyperkinetic (myoclonus, chorea, or other dyskinetic disorders). Some disorders mimic neurodegenerative or hereditary illnesses. The subacute onset and coexisting nonclassic features of paraneoplastic disorders aid distinction. Paraneoplastic autoantibodies provide further information regarding differentiating cancer association, disease course, and treatment responses. A woman with cerebellar ataxia could have metabotropic glutamate receptor 1 autoimmunity, in the setting of Hodgkin lymphoma, a mild neurological phenotype and response to immunotherapy. A different woman, also with cerebellar ataxia, could have Purkinje cytoplasmic antibody type 1 (anti-Yo), accompanying ovarian adenocarcinoma, a rapidly progressive phenotype and persistent disabling deficits despite immune therapy. The list of antibody biomarkers is growing year-on-year, each with its own ideal specimen type for detection (serum or CSF), accompanying neurological manifestations, cancer association, treatment response, and prognosis. Therefore, a profile-based approach to screening both serum and CSF is recommended. Immune therapy trials are generally undertaken, and include one or more of corticosteroids, IVIg, plasma exchange, rituximab, or cyclophosphamide. Symptomatic therapies can also be employed for hyperkinetic disorders.

Autoimmune and paraneoplastic seizures

Seizures are a common feature of autoimmune encephalitis and are especially prevalent in patients with the commonest autoantibodies, against LGI1, CASPR2 and the NMDA, GABAB, and GABAA receptors. In this chapter, we discuss the classification, clinical, investigation, and treatment aspects of patients with these, and other autoantibody-mediated and -associated, illnesses. We highlight distinctive and common seizure semiologies which, often alongside other features we outline, can help the clinical diagnosis of an autoantibody-associated syndrome. Next, we classify these syndromes by either focusing on whether they represent underlying causative autoantibodies or T-cell-mediated syndromes and on the distinction between acute symptomatic seizures and a more enduring tendency to autoimmune-associated epilepsy, a practical and valuable distinction for both patients and clinicians which relates to the pathogenesis. We emphasize the more effective immunotherapy response in patients with causative autoantibodies, and discuss the emerging evidence for various first-, second-, and third-line immunotherapies. Finally, we highlight available clinical rating scales which can guide autoantibody testing and immunotherapy in patients with seizures of unknown etiology. Throughout, we relate the clinical and therapeutic observations to the immunobiology and neuroscience which drive these seizures.

Autonomic nervous system involvement in autoimmune encephalitis and paraneoplastic neurological syndromes

In autoimmune neurological diseases, the autonomic nervous system can be the primary target of autoimmunity (e.g. autoimmune autonomic ganglionopathy), or, more frequently, be damaged together with other areas of the nervous system (e.g. Guillain-Barré syndrome). Patients with autoimmune encephalitis and paraneoplastic neurological syndromes (PNS) often develop dysautonomia; however, the frequency and spectrum of autonomic signs and symptoms remain ill defined except for those scenarios in which dysautonomia is a core feature of the disease. Such is the case of Lambert-Eaton myasthenic syndrome, Morvan syndrome or anti-NMDAR encephalitis; in the latter, patients with dysautonomia have been reported to carry a more severe disease and to retain higher disability than those without autonomic dysfunction. Likewise, the presence of autonomic involvement indicates a higher risk of death due to neurological cause in patients with anti-Hu PNS. However, in anti-Hu and other PNS, as well as in the context of immune checkpoint inhibitors' toxicities, the characterization of autonomic involvement is frequently overshadowed by the severity of other neurological symptoms and signs. When evaluated with tests specific for autonomic function, patients with autoimmune encephalitis or PNS usually show a more widespread autonomic involvement than clinically suggested, which may reflect a potential gap of care when it comes to diagnosing dysautonomia. This review aims to revise the autonomic involvement in patients with autoimmune encephalitis and PNS, using for that purpose an antibody-based approach. We also discuss and provide general recommendations for the evaluation and management of dysautonomia in these patients.

Optimizing the diagnostic performance of neural antibody testing for paraneoplastic and autoimmune encephalitis in clinical practice

The detection of neural antibodies in patients with paraneoplastic and autoimmune encephalitis has majorly advanced the diagnosis and management of neural antibody-associated diseases. Although testing for these antibodies has historically been restricted to specialized centers, assay commercialization has made this testing available to clinical chemistry laboratories worldwide. This improved test accessibility has led to reduced turnaround time and expedited diagnosis, which are beneficial to patient care. However, as the utilization of these assays has increased, so too has the need to evaluate how they perform in the clinical setting. In this chapter, we discuss assays for neural antibody detection that are in routine use, draw attention to their limitations and provide strategies to help clinicians and laboratorians overcome them, all with the aim of optimizing neural antibody testing for paraneoplastic and autoimmune encephalitis in clinical practice.

Epidemiology of paraneoplastic neurologic syndromes

Paraneoplastic neurologic syndromes (PNS), initially depicted as seemingly cryptic remote manifestations of malignancy, were first described clinically in the early 20th century, with pathophysiologic correlates becoming better elucidated in the latter half of the century. There remain many questions not only about the pathophysiology but also regarding the epidemiology of these conditions. The continuous discovery of novel autoantigens and related neurologic disease has broadened the association in classical PNS to include conditions such as paraneoplastic cerebellar degeneration. It has also brought into focus several other neurologic syndromes with a putative neoplastic association. These conditions are overall rare, making it difficult to capture large numbers of patients to study, and raising the question of whether incidence is increasing over time or improved identification is driving the increased numbers of cases. With the rise and increasing use of immunotherapy for cancer treatment, the incidence of these conditions is additionally expected to rise and may present with various clinical symptoms. As we enter an era of clinical trial intervention in these conditions, much work is needed to capture more granular data on population groups defined by socioeconomic characteristics such as age, ethnicity, economic resources, and gender to optimize care and clinical trial planning.

Management of Paraneoplastic Syndromes in the Era of Immune Checkpoint Inhibitors

OPINION STATEMENT

Our understanding of paraneoplastic neurologic syndromes (PNS) has blossomed over the past few decades. Clinicians have access to more robust diagnostic criteria and have a heightened index of suspicion for these disorders. Nonetheless, treatment, which typically includes immunosuppression, and response to treatment, varies. Due to persistent difficulty in making a definitive diagnosis, we favor empiric treatment when a possible diagnosis of PNS is suspected, and other alternative causes have substantially been excluded (e.g., infections, toxic-metabolic derangements, metastasis, or leptomeningeal disease). Treatment of the underlying cancer, if identified, is the first therapeutic step and can prevent disease worsening and in rare cases, can reverse neurologic symptoms. In addition to anti-cancer treatment, first line immunotherapies, which include corticosteroids, intravenous immunoglobulins (IVIG), or plasma exchange (PLEX) are typically used. If partial or no benefit is seen, second line immunotherapeutic agents such as rituximab are considered. Additionally, the severity of the initial presentation and possible risk for relapse influences the use of the latter agents. Symptomatic management is also an important component in our practice and will depend on the syndrome being treated. One of the more novel entities we are facing currently is the management of immune checkpoint (ICI)-induced PNS. In those cases, current American Society of Clinical Oncology (ASCO) guidelines are followed.

Glial Fibrillary Acidic Protein Autoimmunity After Aseptic Meningitis: A Report of 2 Cases

OBJECTIVES

We describe 2 patients with glial fibrillary acidic protein (GFAP) autoimmunity secondary to aseptic viral meningitis or meningoencephalomyelitis.

METHODS

This study involved a retrospective chart review.

RESULTS

Two female patients, 45 and 55 years of age, developed aseptic meningoencephalomyelitis or meningitis; in one patient, it was likely caused by herpes simplex virus 2. The patients were recovering from the infectious condition when they, 51 and 5 days after onset, had new symptoms with detection of GFAP antibodies in the CSF; CSF and serum samples from the initial lumbar punctures had been negative for GFAP antibodies. Both patients recovered with steroid treatment (in one case, plus rituximab; in the other, plus azathioprine) including resolution of MRI and CSF abnormalities.

DISCUSSION

These 2 patients had GFAP autoimmunity secondary to viral meningoencephalomyelitis or meningitis. This suggests that GFAP astrocytopathy might not always be a primary disease entity; it may follow another brain injury that triggers this autoimmune response.

Paraneoplastic/autoimmune myelopathies

Paraneoplastic myelopathies are a rare but important category of myelopathy. They usually present with an insidious or subacute progressive neurologic syndrome. Risk factors include tobacco use and family history of cancer. Cerebrospinal fluid analysis usually shows lymphocytic pleocytosis with elevated protein. MRI findings suggest that paraneoplastic myelopathies include longitudinally extensive T2 hyperintensities that are tract-specific and accompanied by enhancement, but spinal MRIs can also be normal. The most commonly associated neural antibodies include amphiphysin and collapsin-response-mediator-protein-5 (CRMP5/anti-CV2) antibodies with lung and breast cancers being the most frequent oncologic accompaniments. The differential diagnosis of paraneoplastic myelopathies includes nutritional deficiency myelopathy (B12, copper) as well as autoimmune/inflammatory conditions such as primary progressive multiple sclerosis or spinal cord sarcoidosis. Patients treated with immune checkpoint inhibitors for cancer may develop myelitis, that can be considered along the spectrum of paraneoplastic myelopathies. Management of paraneoplastic myelopathy includes oncologic treatment and immunotherapy. Despite these treatments, the prognosis is poor and the majority of patients eventually become wheelchair-dependent.

Case report: Excessive daytime sleepiness as a presenting manifestation of autoimmune glial fibrillary acidic protein astrocytopathy

Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) is a recently discovered autoimmune inflammatory disease of the central nervous system. It presents with a variety of clinical symptoms, including fever, seizures, psychiatric symptoms, limber weakness, and sensory symptoms. However, the symptoms of sleep disorders have not been sufficiently addressed. Here, we report a case of GFAP-A in which the patient complained of excessive daytime sleepiness and an excessive need for sleep. Our patient was a 58-year-old male who experienced excessive daytime sleepiness for 50 days following SARS-CoV-2 infection. He was diagnosed with coronavirus disease 2019 on June 1st. On the 7th of June, he experienced excessive daytime sleepiness, nausea, reduced food intake, lower limb weakness, and dysuria. Subsequently, his sleepiness significantly deteriorated on July 21st. Five months prior, the patient underwent laparoscopic partial right nephrectomy for clear-cell renal cell carcinoma. Brain MRI revealed abnormal hyperintense lesions in the pontine brain and around the mesencephalic aqueduct on T2 and T2-fluid attenuated inversion recovery (T2-FLAIR) sequences However, these lesions did not exhibit any pathological enhancement. Spinal cord MRI revealed lesions in the C6-C7 and T2-T3 segments on the T2 sequence. His Epworth Sleepiness Scale (ESS) score was 16 (reference range, <10), and 24-hour polysomnography supported the diagnosis of rapid-eye-movement sleep disorder and severe sleep apnea-hypopnea syndrome. Glial fibrillary acidic protein IgG antibodies were detected in the cerebrospinal fluid (1:32, cell-based assay) but not in the serum. The level of hypocretin in the cerebrospinal fluid was 29.92 pg/mL (reference range ≥110 pg/mL), suggesting narcolepsy type 1. After treatment with corticosteroids for approximately 1 month, the patient showed considerable clinical and radiological improvement, as well as an increase in hypocretin levels. Although repeated polysomnography and multiple sleep latency tests suggested narcolepsy, his ESS score decreased to 8. Our findings broaden the range of clinical manifestations associated with GFAP-A, thereby enhancing diagnostic and therapeutic strategies for this disease. Additionally, our results indicate a potential common autoimmune mechanism involving GFAP-A and orexin system dysregulation, warranting further investigation.

case of autoimmune GFAP astrocytopathy with eosinophils in the cerebrospinal fluid

Cerebrospinal fluid (CSF) eosinophilia is associated with a narrow differential, primarily including parasitic and fungal infections, neoplasm, and chemical meningitis. It has rarely been reported in neuroinflammatory conditions including as a finding of CSF cytology in two autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy cases. Here we describe a case of autoimmune GFAP astrocytopathy with classic clinical and radiographic features as well as presence of eosinophils in the CSF. This case highlights a potential association of eosinophils in the CSF with autoimmune GFAP astrocytopathy, which may suggest its inclusion in the differential diagnosis of eosinophilic meningitis, encephalitis, or myelitis.

Cervical myelitis: a practical approach to its differential diagnosis on MR imaging

BACKGROUND

 Differential diagnosis of non-compressive cervical myelopathy encompasses a broad spectrum of inflammatory, infectious, vascular, neoplastic, neurodegenerative, and metabolic etiologies. Although the speed of symptom onset and clinical course seem to be specific for certain neurological diseases, lesion pattern on MR imaging is a key player to confirm diagnostic considerations.

METHODS

 The differentiation between acute complete transverse myelitis and acute partial transverse myelitis makes it possible to distinguish between certain entities, with the latter often being the onset of multiple sclerosis. Typical medullary MRI lesion patterns include a) longitudinal extensive transverse myelitis, b) short-range ovoid and peripheral lesions, c) polio-like appearance with involvement of the anterior horns, and d) granulomatous nodular enhancement prototypes.

RESULTS AND CONCLUSION

 Cerebrospinal fluid analysis, blood culture tests, and autoimmune antibody testing are crucial for the correct interpretation of imaging findings. The combination of neuroradiological features and neurological and laboratory findings including cerebrospinal fluid analysis improves diagnostic accuracy.

KEY POINTS

  · The differentiation of medullary lesion patterns, i. e., longitudinal extensive transverse, short ovoid and peripheral, polio-like, and granulomatous nodular, facilitates the diagnosis of myelitis.. · Discrimination of acute complete and acute partial transverse myelitis makes it possible to categorize different entities, with the latter frequently being the overture of multiple sclerosis (MS).. · Neuromyelitis optica spectrum disorders (NMOSD) may start as short transverse myelitis and should not be mistaken for MS.. · The combination of imaging features and neurological and laboratory findings including cerebrospinal fluid analysis improves diagnostic accuracy.. · Additional brain imaging is mandatory in suspected demyelinating, systemic autoimmune, infectious, paraneoplastic, and metabolic diseases..

Glial Fibrillary Acidic Protein (GFAP) Astrocytopathy: An Emerging Cause of Meningoencephalomyelitis in Children and Adolescents

Introduction: We describe 5 children with GFAP astrocytopathy with the goal of further characterizing this rare form of meningoencephalomyelitis. Methods: Retrospective chart review of patients diagnosed with GFAP astrocytopathy between 2019 and 2021. Results: Patients were 8-17 years old, and all were male. Fever, headache, and vomiting were common presenting symptoms, and weakness, tremor, and ataxia were common initial examination findings. Initial magnetic resonance imaging (MRI) showed spinal cord abnormalities in 2 patients and leptomeningeal enhancement in 1. Most patients had cerebral spinal fluid pleocytosis, and all screened negative for malignancy. Three patients progressed to coma, and all were treated with immunosuppressant therapy. By discharge, all patients had improved over their clinical nadir, although none had returned to baseline. Discussion: GFAP astrocytopathy is a recently recognized cause of meningoencephalomyelitis in children. Here, we expand our understanding of this entity with the goal of aiding those treating children with GFAP astrocytopathy.

Beyond Myelin Oligodendrocyte Glycoprotein and Aquaporin-4 Antibodies: Alternative Causes of Optic Neuritis

Optic neuritis (ON) is the most common cause of vision loss in young adults. It manifests as acute or subacute vision loss, often accompanied by retrobulbar discomfort or pain during eye movements. Typical ON is associated with Multiple Sclerosis (MS) and is generally mild and steroid-responsive. Atypical forms are characterized by unusual features, such as prominent optic disc edema, poor treatment response, and bilateral involvement, and they are often associated with autoantibodies against aquaporin-4 (AQP4) or Myelin Oligodendrocyte Glycoprotein (MOG). However, in some cases, AQP4 and MOG antibodies will return as negative, plunging the clinician into a diagnostic conundrum. AQP4- and MOG-seronegative ON warrants a broad differential diagnosis, including autoantibody-associated, granulomatous, and systemic disorders. These rare forms need to be identified promptly, as their management and prognosis are greatly different. The aim of this review is to describe the possible rarer etiologies of non-MS-related and AQP4- and MOG-IgG-seronegative inflammatory ON and discuss their diagnoses and treatments.

Autoantibody status, neuroradiological and clinical findings in children with acute cerebellitis

BACKGROUND

Acute cerebellitis (AC) in children and adolescents is an inflammatory disease of the cerebellum due to viral or bacterial infections but also autoimmune-mediated processes.

OBJECTIVE

To investigate the frequency of autoantibodies in serum and CSF as well as the neuroradiological features in children with AC.

MATERIAL AND METHODS

Children presenting with symptoms suggestive of AC defined as acute/subacute onset of cerebellar symptoms and MRI evidence of cerebellar inflammation or additional CSF pleocytosis, positive oligoclonal bands (OCBs), and/or presence of autoantibodies in case of negative cerebellar MRI. Children fulfilling the above-mentioned criteria and a complete data set including clinical presentation, CSF studies, testing for neuronal/cerebellar and MOG antibodies as well as MRI scans performed at disease onset were eligible for this retrospective multicenter study.

RESULTS

36 patients fulfilled the inclusion criteria for AC (f:m = 14:22, median age 5.5 years). Ataxia was the most common cerebellar symptom present in 30/36 (83 %) in addition to dysmetria (15/36) or dysarthria (13/36). A substantial number of children (21/36) also had signs of encephalitis such as somnolence or seizures. In 10/36 (28 %) children the following autoantibodies (abs) were found: MOG-abs (n = 5) in serum, GFAPα-abs (n = 1) in CSF, GlyR-abs (n = 1) in CSF, mGluR1-abs (n = 1) in CSF and serum. In two further children, antibodies were detected only in serum (GlyR-abs, n = 1; GFAPα-abs, n = 1). MRI signal alterations in cerebellum were found in 30/36 children (83 %). Additional supra- and/or infratentorial lesions were present in 12/36 children, including all five children with MOG-abs. Outcome after a median follow-up of 3 months (range: 1 a 75) was favorable with an mRS ≤2 in 24/36 (67 %) after therapy. Antibody (ab)-positive children were significantly more likely to have a better outcome than ab-negative children (p = .022).

CONCLUSION

In nearly 30 % of children in our study with AC, a range of abs was found, underscoring that autoantibody testing in serum and CSF should be included in the work-up of a child with suspected AC. The detection of MOG-abs in AC does expand the MOGAD spectrum.

Peripheral nervous system involvement accompanies central nervous system involvement in anti-glial fibrillary acidic protein (GFAP) antibody-related disease

BACKGROUND

Glial fibrillary acidic protein (GFAP) is expressed by astrocytes in the central nervous system (CNS), but also by immature and regenerative Schwann cells in the peripheral nervous system (PNS). GFAP antibodies (GFAP-Abs) in cerebrospinal fluid (CSF) have been mainly described in patients with meningoencephalomyelitis. We aimed to study PNS symptoms in patients with CSF GFAP-Abs.

METHODS

We retrospectively included all patients tested positive for GFAP-Abs in the CSF by immunohistochemistry and confirmed by cell-based assay expressing human GFAPα since 2017, from two French reference centers.

RESULTS

In a cohort of 103 CSF GFAP-Abs patients, 25 (24%) presented with PNS involvement. Among them, the median age at onset was 48 years and 14/25 (56%) were female. Abnormal electroneuromyography was observed in 11/25 patients (44%), including eight isolated radiculopathies, one radiculopathy associated with polyneuropathy, one radiculopathy associated with sensory neuronopathy, and one demyelinating polyradiculoneuropathy. Cranial nerve involvement was observed in 18/25 patients (72%). All patients except one had an associated CNS involvement. The first manifestation of the disease concerned the PNS in three patients. First-line immunotherapy was administered to 18/24 patients (75%). The last follow-up modified Rankin Scale was ≤ 2 in 19/23 patients (83%). Patients with PNS involvement had significantly more bladder dysfunction than patients with isolated CNS involvement (68 vs 40.3%, p = 0.031).

CONCLUSIONS

PNS involvement in GFAP-Abs autoimmunity is heterogeneous but not rare and is mostly represented by acute or subacute cranial nerve injury and/or lower limb radiculopathy. Rarely, PNS involvement can be the first manifestation revealing the disease.

Clinical characteristics of patient with GFAP-IgG: a review of 31 patients from two tertiary referral centers in China

OBJECTIVE

This study presents a comprehensive analysis of the clinical characteristics of 31 patients exhibiting cerebrospinal fluid (CSF) and/or serum positivity for GFAP-IgG, with a specific emphasis on 24 cases demonstrating only GFAP-IgG positivity. The investigation thoroughly evaluates their clinical, radiological, and laboratory features, as well as treatment responses, with the objective of offering clinicians potential diagnostic and therapeutic approaches.

METHODS

A total of 31 patients with GFAP-IgG in the CSF and/or serum were registered between August 2016 and August 2021 at the General Hospital of Ningxia Medical University and Huashan Hospital of Fudan University. We retrospectively reviewed their clinical records.

RESULTS

Overall, the patients were positive with GFAP-IgG in their CSF (15/31), in serum (6/31), and both CSF and serum (10/31). Among them, two were eventually diagnosed with astroglioma and primary central nervous system lymphoma, respectively; one patient had typical multiple sclerosis; three exhibited overlapping GFAP-IgG and aquaporin-4-IgG (AQP4-IgG); and one patient was coexisting N-methyl-D-aspartate receptor IgG. The remaining 24 patients were only GFAP-IgG positive. In total, 22 out of the 24 patients had abnormal MRI outcomes, involving the brain, meninges, and spinal cord. Besides, seven of the 24 patients developed optic neuritis. The CSF protein levels positively correlated with the Expanded Disability Status Scale score (EDSSs). Significantly decreased EDSSs, modified Rankin Scale score, GFAP-IgG titer, CSF protein level, and CSF white blood cell counts were observed after immunomodulatory therapy.

CONCLUSION

The clinical manifestations of GFAP-IgG exhibit a wide range of phenotypes that lack specificity. These findings emphasize the significance of not exclusively relying on the presence of antibodies to diagnose GFAP-A, but rather integrating them with the clinical phenotypes. GFAP-IgG testing enables the diagnosis of autoimmune GFAP astrocytopathy, a treatable autoimmune disease affecting the central nervous system. This condition provides opportunities for investigating innovative mechanisms of CNS autoimmunity and inflammation.

Comparison of glial fibrillary acidic protein-immunoglobulin G-associated myelitis with myelin oligodendrocyte glycoprotein-immunoglobulin G-associated myelitis

Objective

Glial fibrillary acidic protein-immunoglobulin G (GFAP-IgG)-associated myelitis and myelin oligodendrocyte glycoprotein-IgG (MOG-IgG)-associated myelitis have rarely been compared. Therefore, this study aimed to explore the clinical, laboratory, and imaging features of them to identify the differences.

Methods

Overall, 14 and 24 patients with GFAP-IgG-and MOG-IgG-associated myelitis, respectively, were retrospectively screened and included in the study.

Results

Among the 14 patients with GFAP-IgG-associated myelitis, the condition was more common in males (71.4%), with a median age of onset of 36.5 years, and more common in adults than in children (35.7%). In contrast, among the 24 patients with MOG-IgG-associated myelitis, the condition was equally divided between males and females, with a median age of onset of 9.5 years and more in children (66.7%) than in adults. The median age of onset of GFAP-IgG-associated myelitis was later than that of the MOG-IgG group. Isolated myelitis was rare in both groups. Elevated cerebrospinal fluid (CSF) protein levels were more prevalent in patients with GFAP-IgG-associated myelitis (64.3%) than in those with MOG-IgG-associated myelitis (16.7%) (p < 0.05), whereas patchy gadolinium enhancement of the cerebral lesion site was less common in patients with GFAP-IgG-associated myelitis than in those with MOG-IgG associated myelitis (p < 0.05). Six patients had a combination of other neurological autoantibodies, the specific mechanism of the overlapping antibodies remains unclear.

Conclusion

Cerebrospinal fluid analysis and gadolinium enhanced MRI examination may help to distinguish the two kinds of myelitis.

Plasma exchange for two patients with autoimmune GFAP astrocytopathy with rapid progression to respiratory failure: a case report

Background

Patients with autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy can present with early neurological deterioration, but rapidly progressive respiratory failure is rarely reported. We present the cases of two patients with autoimmune GFAP astrocytopathy who experienced rapid progression to respiratory failure and were effectively treated using plasma exchange therapy.

Case report

Two patients were diagnosed with autoimmune GFAP astrocytopathy. Their initial symptoms were consistent with those of previously observed cases of autoimmune GFAP astrocytopathy. However, they experienced rapid progression to respiratory failure due to their lesion location. Specifically, case 1 had lesions in the medulla oblongata, and case 2 had lesions in the high cervical spinal cord, which are both common sites of lesions causing respiratory failure. The patients did not respond well to intravenous methylprednisolone and intravenous immunoglobulin initially and could not be withdrawn from ventilator support. Fortunately, subsequent plasma exchange therapy led to significant clinical improvements and successful withdrawal from ventilator support.

Discussion

Patients with autoimmune GFAP astrocytopathy can present with rapidly progressive respiratory failure. Early treatment with plasma exchange can be beneficial in withdrawing patients from ventilator support.

A rare case of glial fibrillary acidic protein astrocytopathy that resolved spontaneously within a self-limited course

Glial fibrillary acidic protein astrocytopathy is a form of autoimmune meningoencephalomyelitis. The presence of antibodies in spinal fluid against glial fibrillary acidic protein is necessary to diagnose the disease. There is no standard treatment and few cases of glial fibrillary acidic protein astrocytopathy have been reported. A 31-year-old healthy Japanese man presented to our emergency department with a 7-day history of fever and headache. He was in good general condition, without abnormalities on physical examination, and a general hematological examination revealed hyponatremia (130 mEq/L). Five days later, he was followed up and new subjective symptoms were noted: tremor in the right hand, constipation, sweating, and lightheadedness. Cerebrospinal fluid examination revealed a cell count of 57/μL (96 % mononuclear cells, 4 % multinuclear cells), elevated protein level (103 mg/dL), elevated adenosine deaminase level (15.0 U/L), negative polymerase chain reaction test results for herpes simplex virus and Mycobacterium tuberculosis, negative cerebrospinal fluid culture, and negative cerebrospinal fluid anti-acid bacteria culture, indicating aseptic meningitis. T1-weighted contrast-enhanced magnetic resonance imaging of the head showed a linear contrast effect perpendicular to the lateral ventricular wall and along the perivascular vessels spreading radially. Based on the presence of hyponatremia, history of movement disorder and autonomic symptoms, high adenosine deaminase level in cerebrospinal fluid, and findings on contrast-enhanced magnetic resonance imaging of the head, we suspected glial fibrillary acidic protein astrocytopathy and assessed anti-glial fibrillary acidic proteinαantibody in cerebrospinal fluid, which was positive, and diagnosed glial fibrillary acidic protein astrocytopathy. After careful follow-up with symptomatic treatment without immunosuppressive therapy, the fever, headache, tremor, and autonomic symptoms were improved over time. Contrast-enhanced magnetic resonance imaging of the head and findings of cerebrospinal fluid also showed improvement. glial fibrillary acidic protein astrocytopathy should be a differential diagnosis in patients with aseptic meningitis with movement disorders or autonomic symptoms and elevated cerebrospinal fluid adenosine deaminase. Careful follow-up without immunosuppressive treatment should be considered for patients with minimal neurologic symptoms as glial fibrillary acidic protein astrocytopathy may have a self-limiting course and resolve.

An update on optic neuritis

Optic neuritis (ON) is the most common cause of subacute optic neuropathy in young adults. Although most cases of optic neuritis (ON) are classified as typical, meaning idiopathic or associated with multiple sclerosis, there is a growing understanding of atypical forms of optic neuritis such as antibody mediated aquaporin-4 (AQP4)-IgG neuromyelitis optica spectrum disorder (NMOSD) and the recently described entity, myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD). Differentiating typical ON from atypical ON is important because they have different prognoses and treatments. Findings of atypical ON, including severe vision loss with poor recovery with steroids or steroid dependence, prominent optic disc edema, bilateral vision loss, and childhood or late adult onset, should prompt serologic testing for AQP4-IgG and MOG-IgG. Although the traditional division of typical and atypical ON can be helpful, it should be noted that there can be severe presentations of otherwise typical ON and mild presentations of atypical ON that blur these traditional lines. Rare causes of autoimmune optic neuropathies, such as glial fibrillary acidic protein (GFAP) and collapsin response-mediator protein 5 (CRMP5) autoimmunity also should be considered in patients with bilateral painless optic neuropathy associated with optic disc edema, especially if there are other accompanying suggestive neurologic symptoms/signs. Typical ON usually recovers well without treatment, though recovery may be expedited by steroids. Atypical ON is usually treated with intravenous steroids, and some forms, such as NMOSD, often require plasma exchange for acute attacks and long-term immunosuppressive therapy to prevent relapses. Since treatment is tailored to the cause of the ON, elucidating the etiology of the ON is of the utmost importance.

Clinical characteristics of autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy in children: A case series of 16 patients

PURPOSE

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

METHODS

We reviewed the medical records of Children's Hospital of Chongqing Medical University from January 2020 to September 2021 and retrospectively analysed the clinical features, magnetic resonance imaging (MRI) findings, laboratory findings, treatment and outcome of children with autoimmune GFAP astrocytopathy.

RESULTS

Sixteen patients were included: 6 and 10 tested positive for GFAP-IgG in cerebrospinal fluid (CSF) and both CSF and serum, respectively. The median patient age was 115 months (range: 36-180 months), and 7 patients (43.8%) were male. All patients had the clinical syndrome of encephalitis/meningoencephalitis with or without myelitis: encephalitis (8), meningoencephalitis (3), encephalomyelitis (1) and meningoencephalomyelitis (4). The most common clinical symptoms were fever (11), altered consciousness (11), headache (10) and seizure (9). Four patients developed central respiratory failure for which mechanical ventilation was needed. All patients showed hyperintense T2-weighted lesions on brain MRI in the cerebral white matter (13), brainstem (11), basal ganglia (11), thalamus (9), and cerebellum (3). Nine patients (56%) had abnormal hyperintense lesions in the bilateral basal ganglia and thalamus. Six of 12 patients who underwent gadolinium-enhanced brain MRI showed abnormal enhancement images, and five of them showed linear perivascular radial enhancement. The modified Rankin scale (mRS) score decreased significantly in most patients after immunotherapy. Two patients with coexisting neural autoantibodies relapsed; however, 15 patients who were followed up successfully had favorable outcomes at the last follow-up.

CONCLUSION

Children with autoimmune GFAP astrocytopathy usually have a clinical syndrome of encephalitis/meningoencephalitis with or without myelitis. Except for the linear perivascular radial gadolinium enhancement pattern, hyperintense lesions in the bilateral basal ganglia and thalamus might be another characteristic brain MRI finding of autoimmune GFAP astrocytopathy in children. Although a few patients with coexisting neural autoantibodies might relapse, children with autoimmune GFAP astrocytopathy usually have favorable outcomes after immunotherapy.

Overlapping Epstein-Barr virus encephalitis and autoimmune glial fibrillary acidic protein astrocytopathy

We describe three cases of overlapping Epstein-Barr virus (EBV) Encephalitis and Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy (GFAP-A). The three cases all presented with initial symptoms of fever, headache, coma, and posture tremor of the upper limbs, then followed by limb weakness and dysuria. All of the three cases were on ventilators. Case 1 and 2 improved dramatically after intravenous methylprednisoloneand immunoglobulin treatment. However, case 3 presented dyspneic, and died from gastrointestinal hemorrhage. The GFAP-A triggered by EBV intracranial infection could initially masquerade as EBV encephalitis only, and the detection of GFAP antibody is essential for differentiation.

Visual System Involvement in Glial Fibrillary Acidic Protein Astrocytopathy: Two Case Reports and a Systematic Literature Review

BACKGROUND AND OBJECTIVES

Glial fibrillary acidic protein (GFAP) antibodies can associate with an astrocytopathy often presenting as a meningoencephalitis. Visual involvement has been reported but scarcely defined. We describe 2 cases of GFAP astrocytopathy with predominant visual symptoms and present a systematic review of the literature.

METHODS

We describe 2 patients with GFAP astrocytopathy from our neurology department. We performed a systematic review of the literature according to PRISMA guidelines, including all patients with this disease and available clinical data, focusing on visual involvement.

RESULTS

Patient 1 presented with bilateral optic disc edema and severe sudden bilateral loss of vision poorly responsive to therapy. Patient 2 showed bilateral optic disc edema, headache, and mild visual loss with complete recovery after steroids. We screened 275 records and included 84 articles (62 case reports and 22 case series) for a total of 592 patients. Visual involvement was reported in 149/592 (25%), with either clinical symptoms or paraclinical test-restricted abnormalities. Bilateral optic disc edema was found in 80/159 (50%) of patients investigated with fundoscopy, among which 49/80 (61%) were asymptomatic. One hundred (100/592, 17%) reported visual symptoms, often described as blurred vision or transient visual obscurations. Optic neuritis was rare and diagnosed in only 6% of all patients with GFAP astrocytopathy, often without consistent clinical and paraclinical evidence to support the diagnosis. Four patients (including patient 1) manifested a severe, bilateral optic neuritis with poor treatment response. In patients with follow-up information, a relapsing disease course was more frequently observed in those with vs without visual involvement (35% vs 11%, p = 0.0035, OR 3.6 [CI 1.44-8.88]).

DISCUSSION

Visual system involvement in GFAP astrocytopathy is common and heterogeneous, ranging from asymptomatic bilateral optic disc edema to severe bilateral loss of vision, but optic neuritis is rare. GFAP CSF antibody testing should be considered in patients with encephalitis/meningoencephalitis or myelitis and bilateral optic disc edema, even without visual symptoms, and in patients with severe bilateral optic neuritis, especially when AQP4 antibodies are negative. Visual symptoms might associate with a higher relapse risk and help to identify patients who may require chronic immunosuppression.

Autoimmune encephalitis: recent clinical and biological advances

In 2015, we wrote a review in The Journal of Neurology summarizing the field of autoantibody-associated neurological diseases. Now, in 2023, we present an update of the subject which reflects the rapid expansion and refinement of associated clinical phenotypes, further autoantibody discoveries, and a more detailed understanding of immunological and neurobiological pathophysiological pathways which mediate these diseases. Increasing awareness around distinctive aspects of their clinical phenotypes has been a key driver in providing clinicians with a better understanding as to how these diseases are best recognized. In clinical practice, this recognition supports the administration of often effective immunotherapies, making these diseases 'not to miss' conditions. In parallel, there is a need to accurately assess patient responses to these drugs, another area of growing interest. Feeding into clinical care are the basic biological underpinnings of the diseases, which offer clear pathways to improved therapies toward enhanced patient outcomes. In this update, we aim to integrate the clinical diagnostic pathway with advances in patient management and biology to provide a cohesive view on how to care for these patients in 2023, and the future.

Magnetic Resonance Imaging Characteristics of Autoimmune Glial Fibrillary Acidic Protein (GFAP) Astrocytopathy: A Pediatric Series in Southwest China

Objective

To investigate and summarize the magnetic resonance imaging (MRI) manifestations of autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy in children.

Methods

We retrospectively analyzed data from 17 pediatric patients with autoimmune GFAP astrocytopathy confirmed by the detection of GFAP autoantibodies in cerebrospinal fluid in our single-center. Furthermore, we reviewed current literature and summarized previous findings on the MRI characteristics of this disease in children.

Results

In these 17 patients, the clinical manifestations and results of CSF analysis were suggestive of autoimmune disorder, with a good improvement. The lesions on MRI were most commonly located in the bilateral basal ganglia (70.6%), thalamus (64.7%), cerebral white matter (29.4%). 93.3% of the cerebral lesions were relatively scattered and small, 80% of the spinal lesions presented as longitudinally extensive ones. Both periventricular radial linear (PVRL) (53.8%) and punctate or linear enhancement in basal ganglia and thalamus (53.8%) were commonly observed, followed by the leptomeningeal enhancement (46.2% in the brain and 62.5% in the spinal cord). We then included 55 pediatric patients with MRI data from current literature in our analysis (n = 72, 44 males). Our results revealed similar MRI findings but the enhancement pattern between our series and previously published cases, that is, leptomeningeal enhancement in the brain 46.2% vs 31.4%, in spinal cord 62.5% vs 18.4%, and PVRL enhancement 53.8% vs 11.2%. There were no detailed reports on punctate or linear enhancement.

Conclusion

The MRI characteristics of autoimmune GFAP astrocytopathy in children could be suggestive. Scattered and small lesions (especially punctate or linear) in the bilateral thalamus, basal ganglia, and white matter, as well as longitudinally extensive spinal cord lesions (if present), with punctate, PVRL and leptomeningeal enhancement might be a distinct indication for the early diagnosis of this disorder.

High frequency of cerebrospinal fluid autoantibodies in patients with seizures or epilepsies of unknown etiology

Introduction

The increasing identification of specific autoantibodies against brain structures allows further refinement of the group of autoimmune-associated epilepsies and affects diagnostic and therapeutic algorithms. The early etiological allocation of a first seizure is particularly challenging, and the contribution of cerebrospinal fluid (CSF) analysis is not fully understood.

Methods

In this retrospective study with a mean of 7.8 years follow-up involving 39 well-characterized patients with the initial diagnosis of new-onset seizure or epilepsy of unknown etiology and 24 controls, we determined the frequency of autoantibodies to brain proteins in CSF/serum pairs using cell-based assays and unbiased immunofluorescence staining of unfixed murine brain sections.

Results

Autoantibodies were detected in the CSF of 30.8% of patients. Underlying antigens involved glial fibrillary acidic protein (GFAP) and N-methyl-D-aspartate (NMDA) receptors, but also a range of yet undetermined epitopes on neurons, glial and vascular cells. While antibody-positive patients had higher frequencies of cancer, they did not differ from antibody-negative patients with respect to seizure type, electroencephalography (EEG) and cranial magnetic resonance imaging (cMRI) findings, neuropsychiatric comorbidities or pre-existing autoimmune diseases. In 5.1% of patients with seizures or epilepsy of initially presumed unknown etiology, mostly CSF findings resulted in etiological reallocation as autoimmune-associated epilepy.

Discussion

These findings strengthen the potential role for routine CSF analysis. Further studies are needed to understand the autoantibody contribution to etiologically unclear epilepsies, including determining the antigenic targets of underlying autoantibodies.

Clinical characteristics and prognostic factors for short-term outcomes of autoimmune glial fibrillary acidic protein astrocytopathy: a retrospective analysis of 33 patients

Background

Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) is a recently discovered inflammatory central nervous system (CNS) disease, whose clinical characteristics and prognostic factors for short-term outcomes have not been defined yet. We aimed to assess the symptoms, laboratory tests, imaging findings, treatment, and short-term prognosis of GFAP-A.

Methods

A double-center retrospective cohort study was performed between May 2018 and July 2022. The clinical characteristics and prognostic factors for short-term outcomes were determined.

Results

We enrolled 33 patients with a median age of 28 years (range: 2-68 years), 15 of whom were children (<18 years). The clinical spectrum is dominated by meningoencephalomyelitis. Besides, we also found nausea, vomiting, poor appetite, and neuropathic pain in some GFAP-A patients, which were not mentioned in previous reports. And adults were more prone to limb numbness than children. Magnetic resonance imaging revealed lesions involving the brain parenchyma, meninges, and spinal cord, exhibiting patchy, linear, punctate, and strip T2 hyperintensities. First-line immunotherapy, including corticosteroid and gamma globulin, was effective in most patients in the acute phase (P = 0.02). However, patients with overlapping AQP4 antibodies did not respond well to first-line immunotherapy and coexisting neural autoantibodies were more common in women. Additionally, the short-term prognosis was significantly better in children than in adults (P = 0.04). Positive non-neural autoantibodies and proven viral infection were independent factors associated with poor outcomes (P = 0.03, 0.02, respectively).

Conclusion

We expanded the spectrum of clinical symptoms of autoimmune GFAP-A. The clinical symptoms and short-term prognosis differed between children and adults. Positive non-neural autoantibodies and proven viral infection at admission suggest a poor short-term prognosis.

Autoimmune glial fibrillary acidic protein astrocytopathy coexistent with reversible splenial lesion syndrome: A case report and literature review

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a rare autoimmune disorder. Reversible splenial lesion syndrome (RESLES) is a transient clinical-imaging syndrome characterized by specific magnetic resonance imaging (MRI) pattern. A 58-year-old man was admitted with a fever, headache, and confusion for 1 week. Brain MRI showed abnormal leptomeningeal enhancement in the brainstem and high signal intensity on diffusion-weighted MRI of the corpus callosum. Anti-GFAP antibody was positive in the serum and cerebrospinal fluid analysis. This patient significantly improved and had no relapse after glucocorticoid and immune suppressant therapy. A repeated brain MRI revealed the lesion in the corpus callosum and abnormal leptomeningeal enhancement in the brainstem disappeared. Linear perivascular radial enhancement is the characteristic pattern of autoimmune GFAP astrocytopathy which is rarely coexistent with RESLES.

Identifying specific myelopathy etiologies in the evaluation of suspected myelitis: A retrospective analysis

BACKGROUND

Myelopathies require prompt etiologic diagnosis. We aimed to identify a specific myelopathy diagnosis in cases of suspected myelitis to highlight clinicoradiologic differences.

METHODS

In this retrospective, single-centre cohort of subjects with suspected myelitis referred to London Multiple Sclerosis (MS) Clinic between 2006 and 2021, we identified those with MS and reviewed the remaining charts for etiologic diagnosis based on clinical, serologic, and imaging details.

RESULTS

Of 333 included subjects, 318/333 (95.5%) received an etiologic diagnosis. Most (274/333, 82%) had MS or clinically isolated syndrome. Spinal cord infarction (n = 10) was the commonest non-inflammatory myelitis mimic characterized by hyperacute decline (n = 10/10, 100%), antecedent claudication (n = 2/10, 20%), axial owl/snake eye (n = 7/9, 77%) and sagittal pencillike (n = 8/9, 89%) MRI patterns, vertebral artery occlusion/stenosis (n = 4/10, 40%), and concurrent acute cerebral infarct (n = 3/9, 33%). Longitudinal lesions were frequent in aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4+NMOSD) (n = 7/7, 100%) and myelin oligodendrocyte glycoprotein-IgG-associated disorder (MOGAD) (n = 6/7, 86%), accompanied by bright spotty (n = 5/7, 71%) and central-grey-restricted (n = 4/7, 57%) T2-lesions on axial sequences, respectively. Leptomeningeal (n = 4/4, 100%), dorsal subpial (n = 4/4, 100%) enhancement, and positive body PET/CT (n = 4/4, 100%) aided the diagnosis of sarcoidosis. Spondylotic myelopathies had chronic sensorimotor presentations (n = 4/6, 67%) with relative bladder sparing (n = 5/6, 83%), localizable to sites of disc herniation (n = 6/6, 100%). Metabolic myelopathies showed dorsal column or inverted 'V' sign (n = 2/3, 67%) MRI T2-abnormality with B12 deficiency.

CONCLUSIONS

Although no single feature reliably confirms or refutes a specific myelopathy diagnosis, this study highlights patterns that narrow the differential diagnosis of myelitis and facilitate early recognition of mimics.

Case Report: Ofatumumab treatment in a patient with rituximab-intolerant refractory autoimmune GFAP astrocytopathy

Background

Ofatumumab, a fully humanized anti-CD20 monoclonal antibody, has shown promising efficacy in limited cases of neuromyelitis optica spectrum disorder, but there is a lack of studies on its use in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy. We present a case of refractory GFAP astrocytopathy with poor response to conventional immunosuppressants and rituximab who responded well to subcutaneous ofatumumab.

Case report

The patient is a 36-year-old woman with a diagnosis of GFAP astrocytopathy and high disease activity. She experienced five relapses over three years despite immunosuppressive treatment with oral prednisone, azathioprine, mycophenolate mofetil, and intravenous rituximab. Additionally, her circulating B cells were not completely depleted during the second administration of rituximab and an allergic reaction occurred. Based on insufficient B cell depletion and allergic reaction to rituximab, subcutaneous ofatumumab was introduced. After twelve injections of ofatumumab without injection-related reactions, she had no further relapses and was sufficiently depleted of the circulating B cells.

Discussion

This case illustrates the effective use and good tolerance of ofatumumab in GFAP astrocytopathy. Further studies are needed to investigate the efficacy and safety of ofatumumab in refractory GFAP astrocytopathy or those intolerant to rituximab.

Immunoreactivity to astrocytes in different forms of dementia: High prevalence of autoantibodies to GFAP

Objective

To study the prevalence of autoantibodies to glial and neuronal antigens with a focus on glial acidic fibrillary protein (GFAP) in patients with dementia.

Methods

Sera of 127 patients with different forms of dementia and sera of 82 age-matched patients with various neurological diseases except for dementia, as well as sera from 15 age-matched healthy controls were analyzed for anti-glial or anti-neuronal IgG using 1) primary murine embryonic hippocampus cell cultures, 2) murine brain sections, 3) immunoblotting on mouse brain homogenates and 4) astrocyte cultures. Sera reacting with astrocytes in hippocampus cell cultures were further analyzed using HEK293 cells transfected with human GFAP.

Results

IgG in serum from 45 of 127 (35.5%) patients with dementia but only 8 of 97 (8.2%, p ≤ 0.001) controls bound to either glial or neuronal structures in cultured murine hippocampus cells. In these cultures antibodies to astrocytes were detected in 35 of 127 (27.5%) of the dementia patients, whereas in controls antibodies to astrocytes were detected in 4 sera only (4.1%, p ≤ 0.001). Among the sera exhibiting reactivity to astrocytes, 14 of 35 (40%) showed immunoreaction to HEK293 cells transfected with GFAP in dementia patients, representing 11% of all sera. Within the 4 immunoreactive control sera reacting with astrocytes one reacted with GFAP (1.0% of total immunoreactivity, p = 0.003).

Conclusions

Autoantibodies to glial epitopes in general and to GFAP in particular are more frequent in patients with dementia than in age-matched controls without dementia, thus indicating the need for further investigations regarding the potential pathophysiological relevance of these antibodies.

Autoimmune glial fibrillary acidic protein astrocytopathy associated with breast cancer: a case report

BACKGROUND

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy (GFAP-A) is an autoimmune inflammatory central nervous system disorder characterized by the detection of autoantibodies that recognize GFAP in CSF. The pathogenesis of GFAP-A is poorly understood. Some patients had a neoplasm detected and GFAP expressed by neoplasms is plausible as immunogen triggering paraneoplastic neurological autoimmunity.

CASE PRESENTATION

We report a case of 76-year-old female patient with GFAP-A complicated with breast cancer. She presented with altered consciousness, nuchal rigidity, speech disturbances, and weakness. Her clinical symptoms were improved by immunotherapy and cancer treatments. Immunohistochemical analysis showed that the restricted tumor expressed GFAP. The infiltration of CD3 + T cells were observed in the peritumoral and intratumoral areas. The most common infiltrating lymphocytes were CD8 + T cells. CD4 + T cells and CD20 + B cells were also observed in the predominant peritumoral area.

CONCLUSIONS

These results suggest that GFAP-A may occur in a paraneoplastic neurological syndrome associated with breast cancer.

Overlapping rheumatoid meningitis with anti-N-methyl-D-aspartate receptor encephalitis: A case report

A 66-year-old woman in treatment for rheumatoid meningitis was found to be positive for anti-N-methyl-D-aspartate receptor (NMDAR) antibodies in the cerebrospinal fluid, and intravenous immunoglobulin improved her psychiatric symptoms. The co-existence of NMDAR antibodies should be considered in cases of poor response to treatments or atypical symptoms in rheumatoid meningitis.

Case report: Autoimmune glial fibrillary acidic protein astrocytopathy misdiagnosed as tuberculous meningitis

Introduction

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a new form of autoimmunity-mediated central nervous system disease. It is especially easy to misdiagnose when clinical symptoms and cerebrospinal fluid (CSF) indicators are similar to those observed in patients with tuberculous meningitis (TBM).

Methods

We retrospectively analyzed five cases of autoimmune GFAP astrocytopathy that were initially misdiagnosed as TBM.

Results

In the five reported cases, all but one patient had meningoencephalitis in the clinic, and all patients exhibited increased pressure, lymphocytosis, increased protein levels, and decreased glucose levels in their CSF results and did not have typical imaging findings of autoimmune GFAP astrocytopathy. TBM was the initial diagnosis in all five patients. However, we found no direct evidence of tuberculosis infection, and anti-tuberculosis treatment had inconclusive effects. Following a GFAP antibody test, the diagnosis of autoimmune GFAP astrocytopathy was made.

Conclusion

When there is a suspected diagnosis of TBM but TB-related tests are negative, the possibility of autoimmune GFAP astrocytopathy should be considered.

Origins and immunopathogenesis of autoimmune central nervous system disorders

The field of autoimmune neurology is rapidly evolving, and recent discoveries have advanced our understanding of disease aetiologies. In this article, we review the key pathogenic mechanisms underlying the development of CNS autoimmunity. First, we review non-modifiable risk factors, such as age, sex and ethnicity, as well as genetic factors such as monogenic variants, common variants in vulnerability genes and emerging HLA associations. Second, we highlight how interactions between environmental factors and epigenetics can modify disease onset and severity. Third, we review possible disease mechanisms underlying triggers that are associated with the loss of immune tolerance with consequent recognition of self-antigens; these triggers include infections, tumours and immune-checkpoint inhibitor therapies. Fourth, we outline how advances in our understanding of the anatomy of lymphatic drainage and neuroimmune interfaces are challenging long-held notions of CNS immune privilege, with direct relevance to CNS autoimmunity, and how disruption of B cell and T cell tolerance and the passage of immune cells between the peripheral and intrathecal compartments have key roles in initiating disease activity. Last, we consider novel therapeutic approaches based on our knowledge of the immunopathogenesis of autoimmune CNS disorders.

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.