Complement inhibition rapidly blocks lesion extension and facilitates remyelination in neuromyelitis optica.

Cumulative disability in neuromyelitis optica spectrum disorder (NMOSD) results from incomplete recovery following inflammatory, demyelinating attacks. Retrospective case studies and current clinical practice indicate that rapid treatment of acute attacks with apheresis limits injury and improves recovery. We evaluated the effects of apheresis and complement inhibition on lesion progression and recovery in a murine ex vivo cerebellar explant model of NMOSD injury. While both strategies reduced lesion formation relative to vehicle treatment, we observed that anti-C5 complement inhibition with eculizumab rapidly halted astrocyte destruction and immediately curtailed lesion extension; whereas an experimental mimic of immunoadsorption (IA), allowed for continued low level astrocyte destruction. During lesion recovery, C5 complement inhibition resulted in a faster rate of oligodendrocyte repopulation and improved myelin repair compared to IA. Complement inhibition may offer multiple benefits for the treatment of acute NMOSD attacks.