Stem cell component therapy: supplementation of unmanipulated marrow with CD34 enriched peripheral blood stem cells

Eleven patients with hematologic malignancies and two with aplastic anemia were treated using unmanipulated marrow and immunoselected CD34+ blood cells. Donors began G-CSF (10 microg/kg) injections 1 day after undergoing bone marrow harvest. Blood stem cells were collected on day 5 of G-CSF. Peripheral blood lymphocytes were depleted via CD34-positive selection. If, after marrow and blood harvest, less than 2.0 x 10(6) CD34 cells/kg were mobilized, leukapheresis was repeated on day 6. Median time to an absolute neutrophil count greater than 500 microl was day 10; transfusion-independent platelet count greater than 20,000/microl was day 13; average hospital discharge was day 14; and average inpatient hospital charges were 101,870 US dollars. Acute GVHD grade II occurred in five of 13 patients. No patient developed grade III or IV acute GVHD. At a median follow-up of 10 months, no patient has developed extensive chronic GVHD. Allografts of unmanipulated bone marrow supplemented with G-CSF-mobilized and CD34 immunoselected blood cells may prevent an increased risk of GVHD while preserving the rapid engraftment kinetics of peripheral blood. Supplementation of marrow with CD34 enriched blood cells appears to result in rapid engraftment, early hospital discharge, lower inpatient charges, decreased regimen-related toxicity, and no apparent increase in GVHD.