Immunoadsorption as maintenance therapy for refractory neuromyelitis optica spectrum disorder

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.

Chimeric AQP4-based immunosorbent for highly-specific removal of AQP4-IgG from blood

Anti-aquaporin-4 autoantibodies (AQP4-IgG) are implicated in the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD), and their removal from the blood circulation is considered to be an effective method for acute treatment. An ideal extracorporeal AQP4-IgG removal system should have high specificity, which means that it can selectively remove AQP4-IgG without affecting normal immunoglobulins. However, the conventional tryptophan immobilized column lacks sufficient specificity and cannot achieve this goal. In this study, we successfully prepared a fusion protein chimeric AQP4, which consists of the complete antigenic epitopes of human AQP4 and the constant region of scaffold protein DARPin. Chimeric AQP4 was expressed and purified from Escherichia coli, and then immobilized on agarose gel as a ligand for selective capture of AQP4-IgG immunosorbent. The prepared immunosorbent had a theoretical maximum adsorption capacity of 20.48 mg/g gel estimated by Langmuir isotherm. In vitro plasma perfusion tests demonstrated that the chimeric AQP4 coupled adsorbent had remarkable adsorption performance, and could eliminate more than 85 % of AQP4-IgG under the gel-to-plasma ratio of 1:50. Moreover, it exhibited high specificity because other human plasma proteins were not adsorbed in the dynamic adsorption experiment. These results suggest that the chimeric AQP4 coupled immunosorbent can provide a new approach for specific immunoadsorption (IA) treatment of NMOSD.

Update on the diagnosis and treatment of neuromyelitis optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part II: Attack therapy and long-term management

This manuscript presents practical recommendations for managing acute attacks and implementing preventive immunotherapies for neuromyelitis optica spectrum disorders (NMOSD), a rare autoimmune disease that causes severe inflammation in the central nervous system (CNS), primarily affecting the optic nerves, spinal cord, and brainstem. The pillars of NMOSD therapy are attack treatment and attack prevention to minimize the accrual of neurological disability. Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) are a diagnostic marker of the disease and play a significant role in its pathogenicity. Recent advances in understanding NMOSD have led to the development of new therapies and the completion of randomized controlled trials. Four preventive immunotherapies have now been approved for AQP4-IgG-positive NMOSD in many regions of the world: eculizumab, ravulizumab - most recently-, inebilizumab, and satralizumab. These new drugs may potentially substitute rituximab and classical immunosuppressive therapies, which were as yet the mainstay of treatment for both, AQP4-IgG-positive and -negative NMOSD. Here, the Neuromyelitis Optica Study Group (NEMOS) provides an overview of the current state of knowledge on NMOSD treatments and offers statements and practical recommendations on the therapy management and use of all available immunotherapies for this disease. Unmet needs and AQP4-IgG-negative NMOSD are also discussed. The recommendations were developed using a Delphi-based consensus method among the core author group and at expert discussions at NEMOS meetings.