dubsitte

Recent stem cell donor here; odds in the US are 1 in 540 according to bethematch.org. If you're familiar with red blood cell donation and the requirements for matching someones blood type, marrow donation takes this to the extreme. The recipient's immune system is replaced by the donor's, so there's a lot of things that can go wrong. You know how your immune system reacts when it comes into contact with germs and other things from outside your body? Just imagine your immune system now implanted in someone else's body. Every recipient experiences some form of graft versus host disease. Finding a close as possible match has to go way beyond a similar blood type to try to limit the reaction to the disease as much as possible.

Unfortunately, yes. Since RA is an autoimmune disease, it wouldn't bode well for any potential recipient.