Preemptive CD8+ T-cell Depleted Donor Lymphocyte Infusion (DLI) Following Nonmyeloablative Stem Cell Transplantation (NMT) for Acute Myeloid Leukemia (AML) or High Risk Myelodysplastic Syndrome (MDS)

The scientific investigation in this study protocol:

1. Define the role of preemptive and specific DLI in preserving the GVL effect in the setting of NMT. The ability of selecting components of T cells for transplant and DLI will allow us to test the hypothesis of distinctive roles in subsets of T cells. It was found that CD8-depleted DLI was administered to prevent relapse after TCD (T-cell depleted) BMT (bone marrow as the stem cell source) or CD34-selected PBSC.

Whether preemptive CD8-depleted DLI can perform this function after nonmyeloablative transplantation (NMT) needs to be established, as proposed in our study. If there turns out to be a role for DLI in these circumstances, a CD8-depleted lymphocyte product that can limit GVHD would be a very attractive option. We would also define the relationship of the level of donor chimerism and disease control. 2. Investigate the impact of CD8-depleted DLI in NMT at specific doses and time points for the reduction of GVHD. The GVHD pattern may vary between different ethnic populations as suggested by our earlier NMT study. Our current proposed study will further shed light on the optimal GVHD prophylaxis regimen in the Singapore patient population.