Quote:
Originally Posted by Neil Cuadra
You are correct that a large number of transfusions can be a disadvantage for a subsequent transplant. I think it interferes with the engraftment process.
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Neil,
I have begun to do a little digging for data on this point, and would be interested in any studies you can point out.
I too have heard, anecdotally, that the number of red cell transfusions can interfere with engraftment, as well as that the acquisition of antibodies in the transfusion process can be a problem for transplant. But I haven't seen studies on those points yet.
I did find
this 2010 study, from the well-known Italian group GITMO (maybe an acronym they might consider changing, at this point). Big caveat: this thread is in the AA section of Marrowforums; the study deals with MDS patients. It is not at all clear to me that what is true about transplant in the MDS world is also true in the AA world.
The key findings of the study are these:
- Red cell transfusion dependence and iron overload have a negative impact on non-relapse mortality (in the neighborhood of 1.5 hazard ratio) but no impact on relapse. (In other words, transfusion dependence and iron overload make it more likely that the transplant will kill you, but not that you'll relapse if you make it past that hurdle).
- The authors believe -- with some decent evidence -- that iron overload may be the ultimate cause of this higher risk among a transfusion dependent patients.
- Transfusion dependent patients with less than 20 lifetime units transfused showed no difference in terms of risk when compared to non-transfusion dependent patients. After that, more units meant (more or less) proportionately more risk.
- After 20 units, the increased risk of non-relapse mortality does increase with the overall number of lifetime units as well as the severity of iron overload measured by increased serum ferritin levels.
- The increased risk of non-relapse mortality among transfusion dependent and iron overloaded patients held only for patients who had myeloablative (big, full, maxi) transplants. Patients who undergo reduced intensity transplants had no increased risk linked to number of transfusions or iron.
- The authors suggested one clinical implication of the study is that folks with a long history of transfusion or high ferritin levels might be advised to go for a reduced intensity, rather than a fully myeloablative transplant.
In plainer English, this study found that MDS patients receiving standard transplants who had more than 20 units of packed red blood cells or ferritin levels above 1,000 were about half again as likely as non-transfusion dependent, non-high ferritin MDS transplant patients to die from the transplant procedure or other causes in the early days after transplant. Folks who fit these descriptions might want to consider reduced intensity transplants.
I'd be interested in other studies that Neil or anyone else has run across on this point. I have located a couple of others I have on my reading list, and I'll report back on them here.
Take care!
Greg