Possible multiple sclerosis disease pathway discovered
Multiple sclerosis (MS) occurs when the immune system attacks parts of the central nervous system, causing inflammation. The trouble is that immune cells have no business crossing the blood-brain barrier meant to protect the brain and spinal cord from such problems. How the barrier is breached has been a puzzle for scientists and clinicians alike.
Now researchers led by Federica Sallusto at the Institute for Research in Biomedicine in Switzerland have found what may literally be the loophole in the system. As reported in Nature Immunology (March 22, 2009), a recently discovered type of immune cell, Th-17, is found to concentrate in an area of the brain implicated as the immune cell entry point, the choroid plexus. In a JAX® Mice strain that models MS, the group found that the mice didn't develop MS-like disease symptoms when they eliminated a receptor that helps regulate how and where Th-17 moves.
If Th-17 cells were to cross the barrier at the choroid plexus and initiate an immune cascade, other immune cells might pass through a compromised barrier in response. Blocking the process could inhibit inflammation in MS patients, though further research is needed with human Th-17 cells to test their possible medical implications.
