http://www.eurekalert.org/pub_releases/2015-10/gi-bcp100915.php
Thank you Dr Zamboni for link to this research

A new study from the Gladstone Institutes shows that a single drop of blood in the brain is sufficient to activate an autoimmune response akin to multiple sclerosis. This is the first demonstration that introduction of blood in the healthy brain is sufficient to cause peripheral immune cells to ente…