Granulocyte recovery after sequential transfusion of mobilized blood stem cell concentrates in syngeneic recipients

Three patients received sequential transfusions of G-CSF-mobilized peripheral blood stem cells from their identical twin in an attempt to abrogate neutropenia. Blood stem cells were harvested by leukapheresis in the healthy donor twins following mobilization with rhG-CSF at 5 μg/kg/day subcutaneously for at least 5 days. An average of 2.2 x 10 7 CFU-GM (range : 1.4-3.3) were collected and transfused without further manipulation. One patient, transfused with a CFU-GM dose of 3 x 10 7 on day +6 after a syngeneic marrow transplant, experienced near-complete elimination of absolute neutropenia until spontaneous engraftment occurred on day +11. In the other two patients, we unexpectedly observed a transient granulopoietic inhibition, possibly related to the high T cell content of the blood stem cell transfusions.