Glial Fibrillary Acidic Protein Astrocytopathy: Review of Pathogenesis, Imaging Features, and Radiographic Mimics

Impaired glymphatic function in autoimmune glial fibrillary acidic protein astrocytopathy: a prospective analysis

BACKGROUND

To evaluate the glymphatic dysfunction and its association with disease severity in autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A) patients, and to determine its clinical predictors.

METHODS

A total of 20 A-GFAP-A patients and 20 healthy controls (HC) were included. All participants underwent magnetic resonance imaging, and glymphatic function was assessed using the diffusion tensor imaging along the perivascular space (DTI-ALPS) index. Modified Rankin Scale (mRS) scores were recorded at baseline and 4 weeks post-immunotherapy. Multiple linear regression analysis was conducted to identify independent predictors of short-term prognosis.

RESULTS

The baseline DTI-ALPS index was significantly lower in A-GFAP-A patients compared to HC (mean ± SD: 1.50 ± 0.06 vs. 1.62 ± 0.04 [CI -0.16, -0.08], p = 0.003), after adjusting for confounding factors. Four weeks after immunotherapy, the DTI-ALPS index significantly increased (mean ± SD: 1.52 ± 0.14 vs. 1.59 ± 0.17 [CI 0.01, 0.14], p = 0.037). A significant negative correlation was observed between the residuals of the baseline DTI-ALPS index and the baseline mRS scores (r = -0.50 [CI -0.77, -0.07], p = 0.025). The baseline DTI-ALPS index was identified as an independent predictor of short-term prognosis (coefficient = -3.43 [CI -6.68, -0.04], p = 0.048).

CONCLUSIONS

This study indicates that A-GFAP-A patients exhibit significant glymphatic dysfunction, as detected by the DTI-ALPS index, which is related to the severity of the disease. The DTI-ALPS index may serve as a biomarker for monitoring disease progression and as a predictor of short-term prognosis in A-GFAP-A patients.

Role of Glial Cells and Receptors in Schizophrenia Pathogenesis

The specific pathogeneses of schizophrenia (SCZ) remain an enigma despite extensive research that has implicated both genetic and environmental factors. Recent revelations that dysregulated immune system caused by glial cell overactivation result in neuroinflammation, a key player in neurodegenerative as well as neuropsychiatric disorders including SCZ are providing novel clues on potential therapeutic interventions. Here, we review the roles of glial cells (Dr. Arne Schousboe's passion) and two of their most implicated receptors, toll-like receptors (TLRs), and nicotinic cholinergic receptors, in SCZ pathology with suggestions as potential targets in this devastating neuropsychiatric condition.

Autoimmune glial fibrillary acidic protein astrocytopathy misdiagnosed as intracranial infectious diseases: case reports and literature review

Background

Autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A) is an autoimmune central nervous system(CNS) disease characterized by GFAP IgG as a biomarker. Several cases of individuals with A-GFAP-A initially misdiagnosed as infectious diseases of the central nervous system have been reported in research. We report three cases of A-GFAP-A misdiagnosed as viral meningitis or tuberculous meningitis (TBM). We summarize recent cases of A-GFAP-A misdiagnosed as central nervous system infections through a literature review.

Materials and methods

Three cases of A-GFAP-A were initially misdiagnosed as tuberculous or viral meningitis. Their diagnoses of A-GFAP-A were confirmed with positive GFAP-IgG in cerebrospinal fluid (CSF). We searched the PubMed database with the key words of "GFAP astrocytopathy", "GFAP autoimmunity", "GFAP autoantibody", "intracranial infection", "meningitis", "misdiagnose", and within the literature from Jan 1, 2015 to Mar 15, 2024, 40 cases with A-GFAP-A with positive GFAP-IgG in CSF who were previously misdiagnosed with intracranial infection were reported. The causes of misdiagnoses were summarized and analyzed.

Results

Case 1 was a 41-year-old female, presenting with headache, fever, diplopia, and altered consciousness level. Anti-tuberculosis treatment was ineffective. Finally, with positive GFAP IgG in CSF, she was diagnosed with A-GFAP-A. Case 2 was a 74-year-old male, presenting with fever, excessive sweating, fatigue, and memory loss. Anti-tuberculosis treatment was ineffective. With positive GFAP IgG in CSF, he was diagnosed with A-GFAP-A. Case 3 was a 54-year-old male, presenting with fever, personality changes, and memory decline. Antiviral treatment was ineffective. His diagnosis was revised to A-GFAP-A after testing positive for GFAP IgG in CSF. Our study summarized a total of 40 patients with A-GFAP-A who were initially misdiagnosed as intracranial infections. The most common clinical phenotypes among 40 patients were mimicked meningitis, meningoencephalitis, meningoencephalomyelitis, encephalitis and encephalomyelitis.

Conclusion

A-GFAP-A is a specific autoimmune meningoencephalomyelitis associated with GFAP-IgG, with lesions involved the brain, meninges, and spinal cord. It commonly presents with symptoms such as fever, headache, altered consciousness, tremor, seizures, and autonomic dysfunction. Brain MRI often shows characteristic linear perivascular radial enhancement perpendicular to the ventricles or nonspecific leptomeningeal enhancement. Early detection of GFAP-IgG in serum and CSF is essential for differential diagnosis.

Unveiling GFAP Astrocytopathy: Insights from Case Studies and a Comprehensive Review of the Literature

BACKGROUND

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy, which was first identified in 2016, is an immune-mediated inflammatory disorder of the nervous system characterized by antibodies targeting GFAP. The exact pathogenic mechanisms, as well as the role of anti-GFAP antibodies, remain unclear; however, it seems that neuroinflammation is mediated by specific CD8+ T-cells and that neoplasms or viral infections can act as the initial trigger. Although the clinical spectrum of the disease is broad and heterogenous, GFAP astrocytopathy most commonly presents as meningoencephalitis with or without myelitis. Other symptoms include headache, visual disturbances, extrapyramidal or brainstem syndromes, and psychiatric manifestations including psychosis. The disease has a characteristically favorable response to steroid treatment while relapses occur in approximately 20-30% of the patients.

METHODS

We present two cases of GFAP astrocytopathy admitted to our hospital: a 43-year-old male with persistent headache and a 59-year-old female with acute dysarthria and swallowing difficulties followed by cognitive and behavioral symptoms.

RESULTS

Additionally, we conduct a comprehensive review of the literature to elucidate the role of anti-GFAP antibodies in disease pathogenesis and examine imaging characteristics, clinical manifestations, and treatment options for this recently described neuroimmunological condition.

CONCLUSIONS

This review presents two unusual cases of GFAP-astrocytopathy and provides evidence for the pathogenesis, clinical presentation, imaging characteristics and treatment options of the disease.

Intercellular Adhesion Molecule 1 (ICAM-1): An Inflammatory Regulator with Potential Implications in Ferroptosis and Parkinson's Disease

Intercellular adhesion molecule 1 (ICAM-1/CD54), a transmembrane glycoprotein, has been considered as one of the most important adhesion molecules during leukocyte recruitment. It is encoded by the ICAM1 gene and plays a central role in inflammation. Its crucial role in many inflammatory diseases such as ulcerative colitis and rheumatoid arthritis are well established. Given that neuroinflammation, underscored by microglial activation, is a key element in neurodegenerative diseases such as Parkinson's disease (PD), we investigated whether ICAM-1 has a role in this progressive neurological condition and, if so, to elucidate the underpinning mechanisms. Specifically, we were interested in the potential interaction between ICAM-1, glial cells, and ferroptosis, an iron-dependent form of cell death that has recently been implicated in PD. We conclude that there exist direct and indirect (via glial cells and T cells) influences of ICAM-1 on ferroptosis and that further elucidation of these interactions can suggest novel intervention for this devastating disease.