Blast colony forming cells in umbilical cord blood: frequency and correlation to other haemopoietic progenitors.

Umbilical cord blood has been suggested as a potential source of haemopoietic stem cells for clinical transplantation. Assay of stroma adherent blast colony forming cells (CFU-BL), as a cell type that may predict marrow repopulation, has already been suggested to predict the outcome of bone marrow transplantation. In the present experiments the frequency of CFU-BL in plastic non adherent mononuclear cell fraction (PNAMNC) of umbilical cord blood was studied. If PNAMNC from cord blood was co-incubated with a pre-established stromal layer from normal bone marrow a strict linear correlation between panned PNAMNC and blast colonies were observed. Frequency of CFU-BL in cord blood was significantly lower than that in bone marrow. In cord blood, CFU-GEMM frequency was found to be comparable to that of bone marrow, CFU-GM and BFU-E frequency was reduced. A good correlation between CFU-BL and BFU-E frequency was found both in cord blood and bone marrow. On the other hand, irrespective of their source, correlation between CFU-BL and CFU-GEMM or CFU-GM was weak.