Despite advances in their classification and treatment, acute leukemia remain incurable disease for the majority of patients. It is necessary to identify new prognostic markers of survival and new therapeutic targets to improve prognosis. Some studies have shown that Fms-like tyrosine kinase 3-ligand (FLT3-L) could be interesting from this. A more recent study from our group testing a novel therapy in acute lymphoblastic leukemia, showed an increase of this marker in the blood of patients responding to treatment. The aim of our prospective, non-interventional study is to measure the plasma levels of FLT3-L at different times of the management of patients with acute lymphoblastic leukemia but also myeloid. For this, analyzes of the samples collected in the usual care will be conducted to study the relationship between the plasma concentration of FLT3-L and outcomes. If there is any link, the FLT3-L could serve as a predictor of treatment response.

Inclusion Criteria:

• Acute myelogenous leukemia diagnosis or lymphoblastic
• Patient intensively treated
• Patients who agreed to participate in the study and having signed the consent biocollection

Non-Inclusion Criteria:

• Patient aged under 18

All adults supported in the Clinical Hematology of the Nantes University Hospital between the beginning of the study and the end of 2017, for the diagnosis and treatment of myelogenous leukemia or acute lymphoblastic requiring intensive chemotherapy and possibly allogeneic haematopoietic stem cells.