To keep the PML discussion in perspective:
European Doctors are not exactly shying away from using Tysabri in immunnosuppressed patients (which is identified as a potential risk factor for higher occurrence of PML)
Natalizumab treatment after autologous haematopoietic stem cell transplantation in patients with aggressive multiple sclerosis
http://registration.akm.ch/einsicht....NMASKEN_ID=900
Any wonder the PML case count is 2 in the US and 7 ex-US (Europe)