CD34 selected cells for the treatment of poor graft function after allogeneic stem cell transplantation

Poor graft function (PGF) is characterized by pancytopenia and a hypoplastic marrow, with complete donor chimerism, usually without severe graft-versus-host disease (GVHD). We report 41 patients with PGF, treated with granulocyte colony-stimulating factor-mobilized CD34 selected cells, at a median interval from transplant of 140days, without conditioning and without GVHD prophylaxis. Donors were HLA matched siblings (n=12), unrelated donors (n=18), or mismatched family members (n=11). The median number of infused CD34⁺ cells was 3.4×10⁶/kg. The rate of trilineage recovery was 75%: 83% for HLA matched siblings and 72% for unrelated and mismatched family members (P=3). The cumulative incidence of acute grade II GVHD was 15%, and no patient developed de novo chronic GVHD. The actuarial 3-year survival is 63%: 76% and 25% for patients with or without trilineage recovery. These data confirm the role of CD34⁺ selected cells from the same donor in the treatment of PGF and warrant the request for a second donation also when the donor is unrelated.