Rescue effects of intravenous immunoglobulin on optic nerve degeneration in a rat model of neuromyelitis optica

Research progress on pathogenesis and clinical treatment of neuromyelitis optica spectrum disorders (NMOSDs)

Neuromyelitis optica spectrum disorders (NMOSDs) are characteristically referred to as various central nervous system (CNS)-based inflammatory and astrocytopathic disorders, often manifested by the axonal damage and immune-mediated demyelination targeting optic nerves and the spinal cord. This review article presents a detailed view of the etiology, pathogenesis, and prescribed treatment options for NMOSD therapy. Initially, we present the epidemiology of NMOSDs, highlighting the geographical and ethnical differences in the incidence and prevalence rates of NMOSDs. Further, the etiology and pathogenesis of NMOSDs are emphasized, providing discussions relevant to various genetic, environmental, and immune-related factors. Finally, the applied treatment strategies for curing NMOSD are discussed, exploring the perspectives for developing emergent innovative treatment strategies.

Intravenous immunoglobulin treatment for steroid-resistant optic neuritis: a multicenter, double-blind, randomized, controlled phase III study

PURPOSE

To evaluate the efficacy and safety of intravenous "freeze-dried sulfonated human normal immunoglobulin (GGS)" in patients with steroid-resistant optic neuritis (ON).

STUDY DESIGN

Multicenter, prospective, double-blind, parallel-group, randomized controlled trial.

METHODS

Patients with steroid-resistant acute ON were randomly assigned to receive either intravenous GGS (GGS group) or intravenous methylprednisolone (steroid pulse [SP] group). Visual acuity (logarithm of the minimum angle of resolution [logMAR]), mean deviation (MD) value of the Humphrey Field Analyzer, and critical flicker fusion frequency were measured as efficacy endpoints; adverse events (AEs) were assessed as the safety endpoint.

RESULTS

Thirty-two patients (16 patients/group) received the study drugs. The primary endpoint, change in logMAR at week 2 compared to baseline, showed no statistically significant intergroup difference. However, compared with the SP group, change in the GGS group was increasingly indicative of visual improvement, with least squares mean difference of > 0.3 logMAR. On post-hoc analyses, the percentage of patients in the GGS and SP groups with improvement by ≥ 0.3 logMAR at week 2 were 75.0% and 31.3%, respectively. Changes in MD values at week 2 compared to baseline were 9.258  ±  8.296 (mean ± standard deviation) dB and 3.175  ±  6.167 dB in the GGS and SP groups, respectively. These results showed statistically significant intergroup differences (visual acuity improvement, P = 0.032; change in MD values, P = 0.030). No clinically significant AEs were observed.

CONCLUSION

Our results suggest that intravenous immunoglobulin could be a safe and efficacious therapeutic option for prompt treatment of steroid-resistant acute ON.

TRIAL REGISTRATION

JapicCTI-132080.

Neuromyelitis optica spectrum disorder: Pathogenesis, treatment, and experimental models

Neuromyelitis optica (NMO) and NMO spectrum disorder (NMOSD) are inflammatory CNS syndromes mainly involving the optic nerve and/or spinal cord and characterized by the presence of serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). The pathology of NMOSD is complicated, while therapies for NMOSD are limited and only partially effective in most cases. This review article focuses on the main pathology of NMOSD involving AQP4-IgG and lymphocyte function. We also review the existing therapeutic methods and potential new treatments. Experimental NMO animal models are crucial for further research into NMO pathology and treatment. However, no AQP4-IgG-immunized animals have been reported. The establishment of NMO models is therefore difficult and primarily depends on the generation of transgenic mice or transcranial manipulation using human or monoclonal mouse anti-AQP4 antibodies. Advantages and disadvantages of each model are discussed.