SCT Question 17

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Question 17

A 35 Y M with AML (normal cytogenetics) patient is transplanted with bone marrow from his 32 Y sister. There was no GVHD and on day 120 he is off immune suppression, counts are normal and BM bx shows no evidence of disease. Myeloid chimerism is 100% donor, while T cell chimerism is 50% donor. Circulating absolute T cell ct is 350/microL.

Next step will be

1. Azacitidine single agent

2. Donor lymphocyte infusion

3. Resume calcineurin inhibitor

4. Observe and repeat blood chimerism in 4-6 weeks

5. Azacitidine + DLI


Option 4. This is a =n intermediate risk AML transplanted with a HLA matched related donor bone marrow, so no big surprise there is mixed T cell chimerism after withdrawal of immunosuppression, given the lower T cell dose administered with BM rather than PBSC. It is important to note that while there is a higher risk of relapse in patients with mixed donor T cell chimerism, the presence of 100% donor myeloid chimerism and absence of disease in marrow, renders the risk-benefit ratio of DLI, prohibitive. Similarly in the absence of residual disease with a myeloablative prep (most likely in a young patient) the value of azacitidine for AML relapse prophylaxis is limited. In patients with high risk FLT3+ disease, midostaurin and gilteritinib may be utilized for relapse ppx. Therefore follow up studies should be done sooner than the usual every three months in the first year following transplant to ascertain stability oof donor hematopoiesis and remission. It is not uncommon to see such stable donor chimerism in the T cells when bone marrow from HLA matched related donors are used. The good T cell count is consistent with robust T cell recovery. In the RIC setting, and with measurable residual disease the likelihood of relapse is significantly increased when patients have mixed T cell chimerism.


Medicine and Health Sciences


Department of Medicine

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