The Elephant in the Room: AML Relapse After Allo-HCT

In patients diagnosed with acute myeloid leukemia (AML) allogeneic hematopoietic cell transplantation (allo-HCT) remains in most cases the only curative option. However, despite major improvements in allo-HCT, disease relapse still remains one of the main causes of mortality. Therefore, strategies aiming to prevent disease relapse or to intervene with preemptive treatments whenever needed, are of upmost importance. Association with adoptive immunotherapies, i.e. donor lymphocyte infusions, also represents a valid strategy. Furthermore, understanding the pathogenetic mechanisms underlying disease relapse represents an active research area as it may help in managing, anticipating and treating disease relapse. Several mechanisms have been advocated such as impaired leukemia cells recognition due to HLA loss, appearance of new leukemic clones, and others. Disease status at time of allo-HCT is a well-known risk factor for early AML relapse after transplantation. In those patients, use of sequential conditioning regimens has been in some cases advocated, despite to date there is no consensus on the best preparative regimen to incorporate.

In this Research Topic, we welcome Original Research articles, Reviews, Mini Reviews, that address AML relapse after allo-HCT and allo-HCT with active disease. The following topics will be of particular interest:

- Conditioning regimens in patients transplanted with active AML
- Management of AML relapse after allo-HCT
- Strategies to prevent AML relapse after allo-HCT
- Treatment of MRD positivity in AML after allo-HCT (preemptive treatment)
- adoptive immunotherapies (DLI)
- mechanisms of AML relapse after allo-HCT (immune escape, HLA loss, etc.)