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

Combined biomaterial scaffold and neuromodulation strategy to promote tissue repair and corticospinal connectivity after spinal cord injury in a rodent model

Spinal cord injury (SCI) damages the trauma site, leading to progressive and secondary structural defects rostral and caudal to the injury. Interruption of ascending and descending pathways produce motor, sensory, and autonomic impairments, driving the need for effective therapies. In this study, we address lesion site repair and promoting descending projections using a combined biomaterial-neuromodulation strategy in a rat model of cervical contusion SCI. To promote tissue repair, we used Chitosan fragmented physical hydrogel suspension (Cfphs), a biomaterial formulation optimized to mitigate inflammation and support tissue remodeling. To promote descending projections, we targeted the corticospinal motor system with dual motor cortex-trans-spinal direct current neuromodulation to promote spared corticospinal tract (CST) axon sprouting rostral and caudal to SCI. Cfphs, injected into the lesion site acutely, was followed by 10 days of daily neuromodulation. Analysis was made at the chronic phase, 8-weeks post-SCI. Compared with SCI only, Cfphs alone or in combination with neuromodulation prevented cavity formation, by promoting tissue remodeling at the injury site, abrogated astrogliosis surrounding the newly formed tissue, and enabled limited CST axon growth into the remodeled injury site. Cfphs alone significantly reduced CST axon dieback and was accompanied by preserving more CST axon gray matter projections rostral to SCI. Cfphs + neuromodulation produced sprouting rostral and caudal to injury. Our findings show that our novel biomaterial-neuromodulation combinatorial strategy achieves significant injury site tissue remodeling and promoted CST projections rostral and caudal to SCI.

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.

[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.

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.