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Falling Chimerism after Reduced Intensity Conditioning Transplantation
A
54-year-old man with AML in second complete remission received a
reduced-intensity conditioning stem cell transplant using fludarabine and
intravenous busulfan. The donor
was an 8/8 HLA-A, B, C and DRB1 matched unrelated male.
GVHD prophylaxis was anti-thymocyte globulin, tacrolimus and
methotrexate 5 mg/m2 on days 1, 3, 6 and 11 with a plan to taper tacrolimus by
30% at day 60, 30% on day 120 and discontinue at 6 months after
transplantation. His tacrolimus
was tapered at day 60 as planned.
Evaluation
at four months after transplantation demonstrated a slightly hypocellular
marrow with no evidence of recurrent disease by either morphology or
cytogenetics. His counts are
normal, and he has no evidence of acute or chronic GVHD.
Tacrolimus level at this time is 2.1 ng/ml.
Serial chimerism studies show:
|
%
Donor in Peripheral Blood
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|
|
|
|
|
Time
Point
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Unfractionated
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CD3+
|
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2
months
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90%
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60%
|
|
4
months
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60%
|
40%
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What
would you recommend?
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