James Bowen, MD – MS Center, Swedish Neuroscience Institute:
Really, the immune system is not broken in NMO so much as it’s working too well. Our immune system is really designed to help fight off infections with things like bacteria and viruses. But in the case of NMO, what happens is the immune system works too well so that it not only defends you against these bacteria and viruses, but it also ends up attacking your own body.
In the case of NMO, this attack seems to be directed at a particular protein that’s named Aquaporin-4. This protein is located within the nervous system, including the brain and the optic nerves and the spinal cord, so the immune system attacking that is what causes the disease. So, in summary, I think that it’s not really broken so much as it’s working too much and has spread from defending you against things like bacteria and viruses toward attacking your own body.