At today's treatment appointment, all of his blood counts levels and magnesium and potassium levels were good enough that no transfusions or infusions were needed. His counts continue to climb which is a good sign that Todd's new bone marrow from his brother (the donor) is engrafting and producing healthy cells.
Two issues at the doctor's appointment were discussed today. First, Todd's blood work from a chimerism study and the rash on Todd's face.
First, the chimerism study. It is a study of the DNA and HLA typed blood cells in Todd that determines how many cells are present from his own bone marrow versus his newly donated bone marrow. These results "lag behind" according to the doctor, so they may not be reflective of the present (they may be older than what is currently happening). This initial report showed that 49% of the cells were from Todd's original bone marrow. (This makes his chimerism mixed.) That means that 51% of his cells are from his newly donated bone marrow from the transplant. The doctor is thinking about repeating this test on Friday to check for more current results. We would all hope to see Todd's cell numbers from his old bone marrow to greatly decrease and the new cells from his newly donated bone marrow would greatly increase. The best result would be that there would be little to none left of Todd's old bone marrow cells.
What is the implication of these results? The chemotherapy that Todd underwent prior to transplant was to kill his own bone marrow since it was not producing healthy cells. There is a possibility that a relapse of Todd's MDS could occur if left unmonitored. The goal of the transplantation process is that the donor's bone marrow will engraft and take over healthy blood cell production. A mixed chimerism of both cells could prevent this from happening. This is where the Graft versus Cancer/Leukemia/tumor (GvL) effect comes in.
This is why monitoring is so important post-transplant. The doctor can manipulate the GvL by altering the amount and type of medications Todd is on now. The doctor is talking about removing Cellcept from Todd's cocktail of medications. The Cellcept is a type of immunosuppressant that keeps the body from developing Graft versus Host disease. The idea here: to allow a little Graft versus Host in the form of Graft versus Cancer/leukemia effect to kill out Todd's old bone marrow to allow more engrafting of his new donated marrow.
I will post updates on this issue as it develops.
Second issue:
The rash that started on Todd's face and neck has spread a bit to his chest and abdomen. It has not changed in intensity at all, so the doctor is still just keeping an eye on it. He will continue to use hydrocortisone on it for now.
Post Script: Date of Chimerism study: Day of release from hospital: October 8, 2014.
More information on chimerism studies:
http://omicsonline.org/2155-9864/2155-9864-S1-006.php?aid=4311
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