Hi Joan,
I am a big fan of UC Davis
I like their team approach for difficult cases.
If the PET scans are indicative of your marrow actively regenerating, I would ask your doctor whether you should taper all the way off cyclosporine. What is your taper schedule? Be very wary of signs of a relapse!
I think that the marrow remains in a very fragile state for some time, depending on the number/state of your remaining stem cells. There is still a colony of rogue T-cells that weren't killed off with the ATG, even if you respond quickly. (ATG is not a cure.) Cyclosporine helps your marrow keep these cells in check until your marrow is strong enough to fight the fight on its own.
How is your cellularity?