Dynamic Changes in AQP4-IgG Level and Immunological Markers During Protein-A Immunoadsorption Therapy for NMOSD: A Case Report and Literature Review

The EBV connection: a severe case of GFAP-A with central hypoventilation unresponsive to IVIG and literature review

PURPOSE

Glial fibrillary acidic protein astrocytopathy (GFAP-A) pathogenesis remains uncertain, with potential viral involvement. More clinical cases are needed to deepen our understanding of this disease, along with the exploration of more effective treatment options to provide clinicians with additional choices.

METHODS

We report a severe case of GFAP-A secondary to EBV infection, characterized predominantly by central respiratory failure. Additionally, we conducted a literature review summarizing the characteristics of GFAP-IgG-positive patients associated with EBV infection.

RESULTS

Among the 13 patients identified, fever (92.3%) and headache (84.6%) were the most common initial symptoms, while urinary dysfunction was universally present in all patients. Over half of the patients with altered consciousness required endotracheal intubation (7/11, 63.6%), with only one individual experiencing complete resolution without any residual sequela. Only two patients (16.7%) displayed the classic feature of periventricular enhancement on neuroimaging, whereas T2-FLAIR hyperintensities were more prevalent. All patients tested positive for GFAP-IgG in CSF, and 91.7% (11/12) had detectable serum GFAP-IgG antibodies. Three patients (23.1%) achieved full recovery solely through antiviral therapy. In patients receiving various immunotherapies, 60% (6/10) still had residual sequelae.

CONCLUSION

EBV infection may contribute to the pathogenesis of GFAP-A. GFAP antibody testing is recommended for diagnostic evaluation in cases of central nervous system viral infections presenting with respiratory insufficiency. For severe GFAP-A patients, Protein A immunoadsorption (Protein A IA).

Protein-A immunoadsorption combined with immunosuppressive treatment in refractory primary Sjögren's syndrome coexisting with NMOSD: a case report and literature review

The treatment of primary Sjögren's syndrome (pSS) coexisting with neuromyelitis optica spectrum disorder (NMOSD) using protein-A immunoadsorption combined with immunosuppressive therapy has rarely been reported. Herein, we present the case of a 35-year-old female diagnosed with pSS concomitant with NMOSD (pSS-NMOSD) who demonstrated a positive response to protein-A immunoadsorption after failing to respond to therapy comprising high-dose intravenous methylprednisolone (IVMP) and intravenous immunoglobulin (IVIG). Within one week of receiving three sessions of immunoadsorption combined with immunosuppressive treatment, the patient's clinical symptoms (blurred vision, paraparesis, and dysfunctional proprioception) significantly improved. Additionally, a rapid decrease in the circulating levels of Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG), immunoglobulin (Ig) A, IgG, IgM, erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF) were observed. Magnetic resonance imaging (MRI) further revealed a significant reduction in the lesions associated with longitudinal extensive transverse myelitis. During the follow-up period, prednisolone was gradually tapered to a maintenance dose of 5-10 mg/day, whereas mycophenolate mofetil (MMF) was maintained at 1.0-1.5 g/day. The patient's condition has remained stable for four years, with no signs of recurrence or progression observed on imaging examination. Therefore, this case suggests that protein A immunoadsorption may represent a potentially effective therapeutic option for patients with pSS-NMOSD who are refractory to conventional treatments.

Efficacy and safety of apheresis therapy in AQP4 antibody-positive NMOSD attack: A propensity score-matched cohort study

OBJECTIVE

Plasma exchange (PE) and immunoadsorption (IA) are recognized as effective ways to treat attacks in AQP4 antibody-positive NMOSD, but high-quality evidence was lacking. To evaluate the efficacy and safety of PE/IA plus intravenous methylprednisolone (IVMP) in NMOSD attacks using propensity scores to match IVMP as control.

METHODS

Patients were from a prospective observational cohort study. Stratification and interval propensity score matching (PSM) were used to reduce selection bias by matching baseline characteristics (gender, age, time to IVMP, EDSS at attack) between PE/IA + IVMP and IVMP group (in a ratio of 1:2). The primary endpoint of efficacy was EDSS change at 6 months. Adverse events and changes in laboratory tests were recorded.

RESULTS

Four hundred and eleven attacks of 336 patients were screened for PSM, and 90 attacks (30 PE/IA + IVMP and 60 IVMP) were included in the analysis. There were significant differences in EDSS [6.25 vs. 6.75; IQR (4.50-8.38 vs. 5.00-8.00), p = 0.671] and visual acuity [median logMAR = 0.35 vs. 1.00; IQR (0.30-0.84 vs. 0.95-1.96), p = 0.002] change between two groups at 6 months. PE/IA + IVMP treatment demonstrated predictive capacity for good recovery as indicated by an area under the curve (AUC) of 0.726. Fibrinogen reduction was found during PE/IA + IVMP treatment [n = 15 (50.00%)], but no severe adverse events led to apheresis treatment discontinuation.

DISCUSSION

After PSM analysis, IVMP+PE/IA in acute attack of NMOSD achieved better and continuous improvement in neurological function within 6 months compared with IVMP alone. PE/IA treatment showed a good safety profile.

APOE from patient-derived astrocytic extracellular vesicles alleviates neuromyelitis optica spectrum disorder in a mouse model

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy of the central nervous system, mediated by antibodies against aquaporin-4 water channel protein (AQP4-Abs), resulting in damage of astrocytes with subsequent demyelination and axonal damage. Extracellular communication through astrocyte-derived extracellular vesicles (ADEVs) has received growing interest in association with astrocytopathies. However, to what extent ADEVs contribute to NMOSD pathogenesis remains unclear. Here, through proteomic screening of patient-derived ADEVs, we observed an increase in apolipoprotein E (APOE)-rich ADEVs in patients with AQP4-Abs-positive NMOSD. Intracerebral injection of the APOE-mimetic peptide APOE130-149 attenuated microglial reactivity, neuroinflammation, and brain lesions in a mouse model of NMOSD. The protective effect of APOE in NMOSD pathogenesis was further established by the exacerbated lesion volume in APOE-deficient mice, which could be rescued by exogenous APOE administration. Genetic knockdown of the APOE receptor lipoprotein receptor-related protein 1 (LRP1) could block the restorative effects of APOE130-149 administration. The transfusion ADEVs derived from patients with NMOSD and healthy controls also alleviated astrocyte loss, reactive microgliosis, and demyelination in NMOSD mice. The slightly larger beneficial effect of patient-derived ADEVs as compared to ADEVs from healthy controls was further augmented in APOE-/- mice. These results indicate that APOE from astrocyte-derived extracellular vesicles could mediate disease-modifying astrocyte-microglia cross-talk in NMOSD.