Factors which affect the CFU-GM content of the peripheral blood haemopoietic progenitor cell harvests in patients with acute myeloid leukaemia

Abstract

Autologous peripheral blood haemopoietic stem cells (PBSC) were harvested from 30 patients with de novo acute leukaemia, 29 of whom had entered remission following standard chemotherapy. Correlation of CD34+ cells/kg to CFU-GM/kg in the harvests was good (correlation coefficient = 0.72, P<0.001). We demonstrated significant associations between the CFU-GM content of the harvest and the following: time to platelets >50x109/l post final induction course (P<0.0001), days to harvest from day 1 of intensification/mobilization (correlation coefficient = -0.73, P<0.001), platelets>20x109/1 at time of harvest (P = 0.02), time to WBC>l.0x109/1 post intensification/ mobilization (correlation coefficient=-0.70, P<0.001), and WBC on day of harvest (correlation coefficient=0.60, P<0.001). In contrast, we found no relationship between the CFU-GM content of the harvest and patient age up to 65 years, presence of absence of coexistent features of trilineage myelodysplasia at diagnosis, number of induction courses to remission or total number of courses of chemotherapy prior to intensification/mobilization. Haemopoletic recovery after reinfusion of PBSC was highly correlated to the number of CFU-GM infused (neutrophils >0.5x109/1 r(s)= -0.72, P=0.001; platelets >20x109/1 unsupported r(s) = -0.71, P=0.001). Our results show that the number of induction courses received, and thus exposure to cytotoxic agents received, made no significant difference to subsequent CFU-GM harvest content. We collected superior harvests from those patients with faster platelet recovery following mobilization therapy. We also found that faster platelet recovery following the final induction therapy was a better predictor of the CFUGM harvest following mobilization than was the neutrophil recovery following final induction.