Yup PML occurs almost exclusively in immunosuppressed individuals, such as patients with AIDS, leukemia, or tumors or those undergoing organ transplants so it makes perfect sense to me that a high power medication aimed at modifying our immune system would also carry some risk.

Everyone has to decide for themself of course but my thoughts are that when this miserable disease becomes too aggressive I'm trying whatever I can regardless of the chance of death. Its sad to have to make these choices but necessary, I guess.