CHARACTERIZATION AND TRANSFUSION OF IN-VITRO CULTIVATED HEMATOPOIETIC PROGENITOR CELLS

Our study is to show the safety of transfusion and the number, phenotype, and proliferative potential of in vitro cultivated autologous hematopoietic peripheral blood progenitor/stem cells (PBPCs). An in vitro long-term liquid culture using PBPC suspension from consenting patients with metastatic breast cancer was established. The medium was supplemented with a variety of hematopoietic growth factors. The mononuclear cells (MNCs), their viability, CD34+ subsets, clonogenic cells, and neutrophil function were measured prior to, during, and after liquid culture for 14 days. The total cell number increased during incubation in vitro from 2.5 x 10(8) to 5 x 10(9). The clonogenic and CD34+ cells increased during the first week 6- and 3.5-fold, respectively, and were almost undetectable after 2 weeks. Maturation into the myeloid cell series was demonstrated by standard cytology and increase of CD33+ and CD38+ cell numbers. On average, 1.5 x 10(9) cells were transfused to consenting patients with metastatic breast cancer after high-dose chemotherapy and PBPC transplantation at nadir of WBC less than or equal to 0.1/nL. One hour later, the mean WBC was measurable at 0.3/nL. Subsequently, WBC counts dropped to 0.2/nL and 0.1/nL at 6 and 24 h post transfusion. No side effects and complications were observed. In summary, an in vitro expansion can produce a greater than or equal to 20-fold increase of maturing PBPCs for an effective and safe autologous transfusion. This unique approach, when refined, could lead to a safer post-transplant period and a decrease of complications due to neutropenic fever.