multiple sclerosis
"Tysabri is the first medication I was put on after being diagnosed with MS. So far it has been very effective, I started taking it after recovering from my first attack. I don't know if it is the Tysabri or just my body healing, but over the last 6 months I have continued to feel fewer and fewer MS symptoms. I was even able to run a marathon recently. 

I do treat positive for the JC virus antibodies, but my doctor had assured me that I can take Tysabri for up to two years with minimum risk of PML.

The injection typically takes 1 hour, with another hour of waiting (something the government had mandated for some reason or another), but I have not felt any side effects."