My cat has immune mediated hemolytic anemia...has anyone experienced this?

I love my cat Patches, he is about 4 1/2 years old, and about 2 months ago he was diagonsed with this. He went through a heck of ride, needing an immediate blood transfusion, bone marrow testing, ultra sound, and IV's. At first they had a few options on what they thought it could be. It started out as possibly lymphoma cancer, or leukema. Thank god it did not come back as either of those, that is when she told me it was the immune sickness and we started him on his medicine. The vet I took him to took care of him so well. I was VERY happy with their service! When we took him into the ER, his anemia level was 7%, and he weighed 2.5 lbs:(. To this day his anemia level is up to 32% and he has DEF. gained weight!! He is currently on prednisone, which has helped A LOT! He is a very playful cat, and is back to being that. We take him now into the vet every 2 weeeks, and so far his medicine has been slightly lowered. The vet told us the better he stays, the lower his medicine will drop. I have read that they can become immune to the medicine but that is why slowly we lower the amount. I was just wondering if anyone has a cat who has been diagnosed with this, and how has it been since?