Had a friend who is involved in MS research look at this article and tell me what it means...

Basically, Tysabri caused an increase in the proliferation of the viruses but the body's humoral response remained stable. This means that the body wasn't making any antibodies to the viruses so it wasn't launching an attack. This is why it said that although there was an increase in the viruses there was no sign of reactivation. One only would see symptoms of reactivation if the immune system was launching an attack as that is what creates the symptoms. If the virus actually gets so concentrated it will interfere with function and then of course you have morbidity which can be fatal. The viruses were being proliferated in the body but the immune system wasn't launching an attack and that certainly is not good!

There still appears to be so much we don't know about PML and it's connection with Tysabri. Hopefully this test will become available soon.

Harry