I quote a discussion between Chris and Lyon on that subject:
A "P.S." here....first, one of the mysteries about MS is the T cell's ability to cross the BBB because NOTHING is supposed to be able to get through.
Sadly Chris, although I thought the same in the beginning, things aren't quite that simple.
With further research I found that there are certain things under a certain size which can go in through even a healthy bbb and when there is problem the immune system is allowed to go in after them.
Currenty I dont have a scientific reference at hand, but I know that there was a study concerning PML in TYSABRI. Where it was found that the immune cells level in the CSF of TYSABRI patients is LOW compared to a much bigger presence in healthy controls.
So it seems common for immune cells to cross the BBB.
In relapses, even if steroids are not used (to shut down inflamation), the relapses pass off naturally after some time...
Is it the case that the inflamation needs replenishments through the BBB, because the immune-cells in the CNS would decay after some time and can not reproduce themself within the CNS?
Treatment: Gilenya since 01/2011, CCSVI both IJV ballooned 09/2010, Tysabri stopped after 24 Infusions and positive JCV antibody test, after LDN, ABX Wheldon Regime for 1 year.