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

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

RATIONALE

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a rare autoimmune disease of the central nervous system that affects the meninges, brain, spinal cord, and optic nerves. GFAP astrocytopathy can coexist with a variety of antibodies, which is known as overlap syndrome. Anti-NMDAR-positive encephalitis overlap syndrome has been reported; however, encephalitis overlap syndrome with both anti-NMDAR and sulfatide-IgG positivity has not been reported.

PATIENT CONCERNS

The patient was a 50-year-old male who was drowsy and had chills and weak limbs for 6 months. His symptoms worsened after admission to our hospital with persistent high fever, dysphoria, gibberish, and disturbance of consciousness. Positive cerebrospinal fluid NMDA, GFAP antibodies, and serum sulfatide antibody IgG were positive.

DIAGNOSES

Autoimmune GFAP astrocytopathy with anti-NMDAR and sulfatide-IgG-positive encephalitis overlap syndrome.

INTERVENTIONS

In addition to ventilator support and symptomatic supportive treatment, step-down therapy with methylprednisolone (1000 mg/d, halved every 3 days) and pulse therapy with human immunoglobulin (0.4 g/(kg d) for 5 days) were used.

OUTCOMES

After 6 days of treatment, the patient condition did not improve, and the family signed up to give up the treatment and left the hospital.

CONCLUSIONS

Patients with autoimmune GFAP astrocytopathy may be positive for anti-NMDAR and sulfatide-IgG, and immunotherapy may be effective in patients with severe conditions.

LESSONS

Autoimmune GFAP astrocytopathy with nonspecific symptoms is rarely reported and is easy to be missed and misdiagnosed. GFAP astrocytopathy should be considered in patients with fever, headache, disturbance of consciousness, convulsions, and central infections that do not respond to antibacterial and viral agents. Autoimmune encephalopathy-related antibody testing should be performed as soon as possible, early diagnosis should be confirmed, and immunomodulatory therapy should be administered promptly.

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.

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.

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.

Astrocytes in the initiation and progression of epilepsy

Epilepsy affects ~65 million people worldwide. First-line treatment options include >20 antiseizure medications, but seizure control is not achieved in approximately one-third of patients. Antiseizure medications act primarily on neurons and can provide symptomatic control of seizures, but do not alter the onset and progression of epilepsy and can cause serious adverse effects. Therefore, medications with new cellular and molecular targets and mechanisms of action are needed. Accumulating evidence indicates that astrocytes are crucial to the pathophysiological mechanisms of epilepsy, raising the possibility that these cells could be novel therapeutic targets. In this Review, we discuss how dysregulation of key astrocyte functions - gliotransmission, cell metabolism and immune function - contribute to the development and progression of hyperexcitability in epilepsy. We consider strategies to mitigate astrocyte dysfunction in each of these areas, and provide an overview of how astrocyte activation states can be monitored in vivo not only to assess their contribution to disease but also to identify markers of disease processes and treatment effects. Improved understanding of the roles of astrocytes in epilepsy has the potential to lead to novel therapies to prevent the initiation and progression of epilepsy.

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 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.

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.