CFU-GM growth from peripheral blood stem cells (PBSC) before and after cryopreservation - Comparison with bone marrow cells

We have compared the CFU-GM growth observed in 29 PBSC samples (8 HL, 21 NHL) to that obtained with 30 bone marrow (BM) ''buffy coats'' harvested for an autologous BMT program in pts without BM involvement (25 AML, 3 HL, 2 NHL). The CFU-GM tests were performed before cryopreservation, made without noncontrolled heat fusion, and after thawing. The collections of PBSC were made with a CS3000 Plus (Baxter). The apheresis were performed after mobilisation with HD CTX 4 g/m(2) and administration of G-CSF (6-15 days). The cultures of CFU-GM were made in methylcellulose for PBSC and in agar monolayer for BM cells, using a conditioned medium from 5637 cell line as source of CSF. Before freezing a mean the CFU-GM growth of from BM cells were higher than in PBSC (35.5 vs 26 : P < 0.05), on the contrary, after thawing the proliferative activity was more elevated for PBSC (21 CFU-CM vs 18). The recovery after thawing, was better for PBSC: 21 CFU-GM 82% (range 50-100%) than for BM cells 51% (range 21-100%). Our data confirm that PBSC have growth activities comparable BM cells. The better viability demonstrated after thawing could help the faster recovery from cytopenia post chemotherapy signalled from many authors.