[Effect of recombinant human FLT3 ligand (rhFL) on in vitro expansion of human cord blood CD34+ cells].

OBJECTIVE: To determine the effects of recombinant human FLT3 ligand (rhFL) on in vitro expansion of human cord blood CD34+ cells. METHODS: Human cord blood CD34+ cells were enriched by using a magnetic cell isolation system. CD34+ cells were incubated in liquid culture in the presence of different cytokines. The total number of all cells and the number of CD34+ cells and hematopoietic progenitor cells (CFU-GM and BFU-E) were counted at various time intervals. RESULTS: Human cord blood CD34+ cells could be enriched to the purity of more than 80%. The number of CD34+ cells increased 3.4 folds in the presence of rhFL + IL3 + IL6 + GMCSF + EPO in seven days, while in the control group without rhFL, it increased 1.5 folds. The difference of the number of more matured hematopoietic progenitor cells in the CD34+ cell population between the control group and the rhFL group was not significant. CONCLUSION: Only the primitive hematopoietic progenitor cells are expanded by rhFL according to the results obtained in the exclusion method.