http://www.belvoireagle.com/health/...tivate-autoimmune-response-in-brain-5059.html
A single drop of blood in the brain is sufficient to activate an autoimmune response akin to multiple sclerosis (MS), proved by a new study from the Gladstone Institutes. This is the first demonstration that introduction of blood in the healthy brain is sufficient to cause peripheral immune cells to enter the brain. It will then go on to cause brain damage.
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Fibrinogen activated the brain’s immune cells, called microglia, and caused them to send out signals summoning peripheral immune cells from other parts of the body to the brain. When these peripheral immune cells–macrophages and T cells–entered the brain, they attacked myelin.