Summary:Between February 1998 and October 1999, 24 patients with advanced leukemia, lymphoma or solid tumors received G-CSF mobilized peripheral blood stem cells (PBSC) from HLA-matched sibling donors after dosereduced conditioning therapy. Only patients with reduced performance status or major infectious complications, not eligible for standard transplant procedures, were included. The 5-day conditioning therapy consisted of 3.3 mg/kg intravenous busulphan × 2 days and 30 mg/m 2 fludarabine × 5 days. GVHD prophylaxis was performed with either CsA alone (n = 5), CsA combined with short course methotrexate (n = 5) or mycophenolate mofetil (n = 14). The day 100 survival was 95.2% for the whole group. All patients engrafted after a median of 15 days (range, 11-19) and 12.5 days (range, 10-19) for neutrophils and platelets, respectively. The median time to a neutrophil count of Ͻ0.5 × 10 9 /l was 7 days (range, 2 to 12). Acute GVHD ϾI was observed in six patients, whereas eight patients have signs of chronic GVHD. The prospective 12 month overall survival with a median follow-up of 7 months is 63%. Relapse of disease and toxicity associated with chronic GVHD were the main causes of death. The treatment-related mortality was 12.5%. Dose-reduced conditioning using intravenous busulphan and fludarabine allows stable engraftment without ATG in related transplants and leads to a reduction of transplant-related mortality. Bone Marrow Transplantation (2000) 26, 119-125.

We investigated the ability of both acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) blasts to differentiate into dendritic cells (DC) in vitro.Cytokine-supplemented suspension cultures of leukemic blasts in 98 patients with AML and five patients with ALL (normal karyotype, n = 2; BCR/ABL, n = 3) were performed. Mononuclear cells out of peripheral blood or bone marrow containing between 60% and 90% leukemic blasts were cultured for eight days using different growth factor combinations.The highest yield of CD1a Leukemic DC can be generated out of leukemic progenitors in patients with AML. These cells might become relevant for autologous and allogeneic immunotherapy in selected patients. BCR/ABL-positive lymphoblasts could not be transformed into cells with an early dendritic phenotype with the cytokines used in our experiments.

Ex vivo expansion of human umbilical cord blood cells (HUCBC) is explored by several investigators to enhance the repopulating potential of HUCBC.We performed experiments using either Ficoll-separated or CD34