Content of long-term culture-initiating cells, clonogenic progenitors and CD34(+) cells in apheresis harvests of normal donors for allogeneic transplantation, and in patients with acute myeloid leukaemia or multiple myeloma

Using a limiting dilution assay the frequency of lone-term culture-initiati ng cells (LTC-IC) in the apheresis products following mobilization by granu locyte-colony stimulating factor (G-CSF) with or without chemotherapy from 14 normal donors (ND) for allogeneic bone marrow transplantation, 16 patien ts with multiple myeloma (MM) and 15 patients with acute myeloid leukaemia (AML), where the aphereses were intended for autologous transplantation. we re compared. The estimated median incidences of LTC-IC in the first apheresis products f rom NU, MM and AML were 1/3289, 1/1775 and 1/13075 mononuclear cells (MNC) respectively. The patients with AML had a significantly lower incidence com pared with the other two groups (P < 0.0001). There was a positive correlat ion between the incidence of LTC-IC and the number of CD34(+) cells, the nu mber of GM-CFC. and the number of BFU-E. The positive association with GM-C FC or BFU-E was weaker. In these experiments the percentage of CD34(+) cell s was the best predictor for the frequency of LTC-TC in the peripheral bloo d progenitor cells (PBPC). In eight cases of MM the LTC-IC assay was perfor med for both the first and second harvest. All cases had a lower LTC-IC fre quency in the second harvest compared with the first, an average of 23% (13 -42%,. 95% confidence interval) and this reduction was statistically signif icant (P < 0.001): CD34(+) cells were also lower (P < 0.001).