We report a case of aquaporin-4 immunoglobulin G (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (NMOSD) and hepatitis C virus (HCV) infection, effectively treated with inebilizumab.

NMOSD is an inflammatory autoimmune disorder, with optic neuritis and transverse myelitis being the most prevalent manifestations. While treatment options for NMOSD have diversified, there is an increasing awareness of the risks associated with hepatitis B reactivation and severe infection. However, there is no consensus on the optimal management strategy for NMOSD patients with coexisting HCV infection.

Case report

A 57-year-old female with a history of recurrent optic neuritis and myelitis from 2011 to 2016 was diagnosed with AQP4-IgG seropositivity NMOSD in 2016. She maintained clinical stability for eight years on azathioprine (100mg/day) and low-dose prednisone (10mg/day). In February 2024, she presented with right limb numbness and pain. Her AQP4-IgG titer was 1:1000, and spinal cord magnetic resonance imaging (MRI) revealed patchy abnormal signals at T3 level and the conus medullaris. Her HCV DNA concentration was exceedingly high at 1.67×10⁷ IU/ml, with a genotype is 3a, which is prevalent in China. Prior to initiating inebilizumab treatment in June 2024, she received antiviral therapy. She exhibited a positive response to B cell deletion treatment. One month post-treatment follow-up showed a negative HCV DNA status. Throughout the follow-up period, there was a progressive improvement in her neurological symptoms without any hepatitis C reactivation or liver function deterioration.

In this case, no HCV outbreaks, liver function worsening, or adverse events were observed at the final follow-up. Our findings suggest that inebilizumab is both safety and effective in NMOSD patients with HCV infection, especially when administered following anti-HCV therapy. Further verification through long-term follow-up and large-scale studies is warranted.