Anemia in FeLV+ cat did not respond to transfusion. Advice?

Desperately seeking input!  Rumi's RBC was climbing yesterday following a transfusion administered in the early AM.  Today those numbers are back down to where he first started: 14%.  He's on prednisone and another immunosuppressant (starts with an "m", mico-something?) because his white blood cells are attacking the red.  

They're performing another transfusion, cross-matched this time, and I pushed for a B-12 injection despite the doc's opinion that it wouldn't be beneficial.  Hoping for a much better outcome this time, but I wonder if there's anything else that can be done.  I decided to forgo cancer testing because it would be far too advanced at this stage and chemo isn't going to buy us much time.  We're all hoping it's simply an "immune mediated response" that can be reined in with this second transfusion.  

If he doesn't get better, please, be honest, is it just palliative care from this point forward or is there something else my vet can look into?  An experimental drug, etc., that might help this nasty, possibly non-regenerative, anemia?

Any advice is greatly appreciated!

Edit: Any opinion on whether or not he can take immune boosting supplements at this time (like a mushroom combo)?  Would they essentially work against the immunosuppresant drugs?

Sorry, I don't understand.  Does he have FeLV?

Riley1 said:

 
Sorry, I don't understand.  Does he have FeLV?

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Yes.  The anemia is a result of the FeLV.  

Edit:  Sorry, dum dum moment.  You were wondering why I mentioned cancer, yes?  That would be because FeLV, having caused a severely damaged immune system, can lead to different cancers, including blood and bone.

Really, really, really need some help figuring this out.  Right now Rumi's bone marrow isn't producing red blood cells, says the doc because there aren't any reticulating (sp?) cells, but he does have some abnormally large red cells, which seems to point to some degree of regeneration (since larger means younger, I guess).  She also says the white cells are attacking the red, so there's that craziness going on as well.  Anyone versed in this stuff from personal or professional experience like to weigh in on what the heck is going on?  

Assuming it's nonregenerative anemia, absolutely a product of the FeLV, is there ANY treatment that could help aside from immunosuppressants?  DepoMedrol?  Epogen?  Please throw me a bone here, someone    (I'm not above begging...)  I don't know any vets with extensive experience treating this disease, so I am just foundering here.  I'll have a copy of his records in hand later and can answer any questions in more detail at that point, should anyone want more details.  But please let me know if you need more detailed info.  Ask and receive.  

He did not have a second transfusion because his numbers went up a few points and his vitals are normal, he's behaving like a perfectly healthy cat.  Is this a good sign?