First described 125 years ago, neuromyelitis optica spectrum disorder (NMOSD) remains a mysterious condition.<sup>1</sup> Often mistaken for multiple sclerosis, people living with this chronic autoimmune disease suffer from blindness, muscle weakness, paralysis, and even death.<sup>2</sup>
To get under the skin of this mysterious disease, further research around the body’s response and what causes the symptoms of NMOSD is required. We may then be able to tailor future treatments for people living with this rare and debilitating disease of the central nervous system.
Although the exact cause of NMOSD remains unknown, there is strong research that points to interleukin-6 (IL-6) as playing a key role in the inflammation that occurs in people with NMOSD, which can lead to unpredictable and severe relapses.2,3
IL-6 is a protein in our bodies made by immune cells and research has shown excess production of IL-6 in the blood and brain of those diagnosed with active NMOSD.3
IL-6 plays a key role in regulating the immune response to molecules that promote inflammation in the body. This includes the production of a harmful antibody that targets a protein called aquaporin-4 (AQP4).3
These AQP4 antibodies target and damage an important group of cells called astrocytes, which are star-shaped cells found in the optic nerves, brain and spinal cord.4,5
Astrocytes have a number of roles, including signalling for the production of other substances in the body and the maintenance of the blood-brain barrier, a layer of cells that protect the brain.6
IL-6 can also weaken the blood-brain barrier. This allows AQP4 antibodies and other cells that cause inflammation to have direct access to the brain and spinal cord.4 In response, astrocytes in the brain and spinal cord produce even more IL-6, causing further damage and ultimately leading to the debilitating symptoms that occur in people with NMOSD.7
Currently there are few treatment options for people living with NMOSD, and there is no cure for the condition. At Roche, we are focusing on the knowledge of IL-6 to investigate treatments for NMOSD and other auto-immune CNS diseases. We have developed a humanised monoclonal antibody that targets the IL-6 receptor, which is believed to play a key role in the inflammation that occurs in people with NMOSD leading to damage and disability.
We believe in taking an innovative approach to research and development – our aim is to never stop following the science, ensuring we’re doing now what patients need next with a view to helping them preserve what makes them the people they are.
Jarius S, Wildemann B. The history of neuromyelitis optica. J. Neuroinflammation. 2013; 10:8: 1-12.
Ajmera MR, et al. Evaluation of comorbidities and health care resource use among patients with highly active neuromyelitis optica. J. Neurol. Sci. 2018; 384: 96-103.
Chihara N, Aranami T, Sato W, Miyazaki Y, Miyake S, Okamoto T, et al. Interleukin 6 signalling promotes anti‐aquaporin 4 autoantibody production from plasmablasts in neuromyelitis optica. Proc Natl Acad Sci USA. 2011; 108: 3701–6.
Hillebrand S, et al. Circulating AQP4-specific autoantibodies alone can induce neuromyelitis optica spectrum disorder in the rat. Acta Neuropathologica. 2019; 137: 467-485.
Yi W, Schlüter D, Wang X. Astrocytes in multiple sclerosis and experimental autoimmune encephalomyelitis: Star-shaped cells illuminating the darkness of CNS autoimmunity. Brain Behav Immun. 2019; 80: 10-24.
Blackburn D,et al.Astrocyte function and role in motor neuron disease: A future therapeutic target? Glia. 2009; 57:12: 1251-1264.
Uzawa A, et al. Role of interleukin-6 in the pathogenesis of neuromyelitis optica. Clin. Exp. Immunol. 2013; 4: 167-172.