[A simple method for detecting immature precursors after in vitro bone marrow treatment with ASTA-Z 7654].

Cyclophosphamide derivatives for in vitro use, such as mafosphamide L lysine (ASTA-Z 7654) are capable of removing residual leukaemic cells from the bone marrow used for autologous transplantation. ASTA-Z also removes committed stem cells detected in semi-solid cultures (CFU-GM). However, haemopoiesis is preserved by more immature progenitors, undetected in usual cultures but detectable in liquid culture of 21 days (MTC). After treating 15 normal bone marrow specimens with 100 microM ASTA-Z, CFU-GM cultures and medium-term cultures (MTC) are carried out. CFU-GM are cultured on the 21st day of incubation from the cell suspension of the MTC. The CFU-GM made the day of in vitro treatment (0.9 colonies/plate) reappear in the CFU-GM cultures performed on the 21st day of incubation of MTC (42 colonies/plate), although the figures attained in parallel controls without any treatment are not fully reached.