Multicentre European study comparing selection techniques for the isolation of CD34+ cells.

Primitive haemopoietic cells are required for studies in both the clinical and research fields and a number of systems have been developed to facilitate isolation of these haemopoietic cell populations. We have analysed the results from several European centres using positive selection of CD34+ cells from haemopoietic tissues (n = 110). Four selection techniques including immunoaffinity columns (Ceprate LC), immunomagnetic beads (Dynabeads, Baxter Isolex 50) and submicroscopic magnetic beads (MACS) were used and the selected CD34+ cells were assessed for purity, yield and enrichment of colony-forming cells (CFC). The mean purities for all samples ranged from 68.4-78.4% for MACS, 33.9-69.9% for Dynabeads, 46.9-66.8% for Ceprate LC and 43.2-65% for Baxter Isolex 50. Yields were variable with all techniques. On average CFC enrichment using the immunoaffinity columns was greater than that observed for the other systems. Some techniques appear to be problematic and may require further expertise to improve the results. Nevertheless, the study demonstrates that highly purified CD34+ cells can be isolated from various haemopoietic sources, though yield and CFC enrichment varies significantly depending on the technique selected. This extends our previous report indicating that not all selection methods generate similar results and that there are differences in the purity, number and colony-forming ability of the cells recovered.

Decreased blood flow to rat bone marrow, bone, spleen, and liver in acute leukemia.

An acute promyelocytic leukemia in the rat (BNML) has been used in model studies on pathogenesis and therapy of human acute myeloid leukemia. The blood supply to bone marrow during BNML development has hitherto not been examined, even though in general, blood flow to hematopoietic tissues might affect drug treatment and marrow transplantation regimes. We measured the perfusion of various organs during the course of the disease in untreated rats and in rats given one injection of cyclophosphamide treatment. Organ perfusion was measured with radioactive microspheres. Blood flow per gram tissue to the bone marrow, bone, spleen, and liver declined gradually during the leukemic progression, thus paralleling the growth of leukemic deposits. Cyclophosphamide treatment retarded, but did not reverse, the decreasing perfusion of these tissues.