Background: The identification of leukemic relapses characterized by the Human Leukocyte Antigens loss event or by changes in the expression levels of genes involved in antigen presentation and lymphocyte co-stimulation demonstrate how a complete characterization of disease recurrence is necessary to ensure the patient a treatment that is as personalized and targeted as possible, avoiding the choice of sub-optimal or, sometimes, harmful therapies. Unfortunately, the identification of the post-transplant relapse mechanism is now far from being part of an established clinical routine, mainly due to the lack of quick and easy-to-access diagnostic tools and multicentre studies demonstrating the efficacy of a type of personalized therapeutic approach.~The main objective of the study is to favor, exploiting the consolidated collaboration between the Italian transplant centers belonging to the Italian Group of Bone Marrow Transplantation, Hematopoietic Stem Cells and Cell Therapies (GITMO), the implementation in clinical practice of an in-depth biological study of relapses of leukemia in order to allow an increasingly targeted and effective planning of the therapeutic strategies to be implemented, ensuring better patient survival.~The study is divided into two parts:~data collection, from clinical standard practice, of patients with relapse of the disease which will allow to standardize the therapeutic management process and will allow us to promote innovative clinical studies on acute myeloid leukemia post allogeneic HSCT, with the ultimate aim of improving the survival of these patients;~biological substudy that will allow to define the role of the tumor microenvironment in promoting or counteracting the phenomenon of relapse by identifying its specific alterations in the various forms of disease relapse.
This is a retrospective and prospective non-interventional multicenter observational study. Neither diagnostic approaches nor experimental drugs/procedure will be applied and the samples will take place at the same time as the samples will be taken during routinary clinical practice.~The aim of this study is to analyze the immunobiology of Acute Myeloid Leukemia (AML) relapses after allogeneic HSCT for the generation of guidelines and personalized therapeutic pathways.