Abstract: The invention relates to therapeutic compounds which are inhibitors of serine proteases, to pharmaceutical compositions thereof and to their use in the treatment of the human or animal body. More specifically, the present invention relates to a method for the treatment of neutropenia comprising the administration to a subject in need thereof of a therapeutically effective amount of a serine protease inhibitor. The invention also comprises prevention of apoptosis of myeloid cells (1) during and after transfection of bone marrow cells performed for gene therapy, (2) during blood stem cell mobilization performed for reconstitution of hematopoiesis and (3) during infusion of cells of the myeloid lineage for reconstitution of hematopoiesis for gene therapy or for treatment of neutropenia by infusion of neutrophils.