Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for a variety of hematological malignancies. However, patients who have received this treatment have a persistent deficit in humoral immunity up to one year post-transplant. To date, the design of new therapeutic strategies to improve immune recovery in allo-HSCT patients is still hampered by the fact that post-transplant regenerative hematopoiesis has never been studied, and more generally by our currently limited knowledge on the development and function of human B lymphocytes. The main objective of our study is to study early B-cell progenitor reconstitution after allogeneic hematopoietic stem cell transplantation.

Inclusion Criteria:

Patients :

• 18 years of age and older
• with hematological malignancies and subject to allogeneic HSCT
• with health insurance coverage (bénéficiaire ou ayant droit)
• having signed a written informed consent.

Inclusion criteria of donor

• 18 years of age and older
• with health insurance coverage (bénéficiaire ou ayant droit)
• having signed a specific written informed consent.

Exclusion criteria of recipient and donor

• Absence of written informed consent
• Patient or donor on AME
• Patient or donor on AME or under protection by law, tutorship or curatorship
• Pregnant women

Patients aged 18 years and older with hematological malignancies and subject to allogeneic HSCT