Objective: We analysed peripheral blood progenitor cell (PBPC) mobilisation and collection in order to assess the main factors related to CD34(+) cell yields in patients affected by haematological malignancies.
Patients and methods: The features of CD34(+) cell mobilisation of patients with haematological malignancies that underwent autologous bone marrow transplantation were examined. Mobilisation chemotherapy consisted mainly of cyclophosphamide (CY) 4 or 7 g/m(2) followed by growth factors. Leukapheresis was started when the WBC counts reached 1.0x10(9)/l with the aim to collect at least 5x10(6) CD34(+) cells/kg body weight. The aphereses were performed on continuous-flow blood cell separators. The analysed variables were: age, diagnosis, CT mobilisation regimen, type of growth factor, number of previous CT lines, prior radiotherapy, days for WBC recovery and number of aphereses procedures to achieve the target of CD34(+) cells.
Results: There were 41 consecutive patients (26 M/15 F): 21 non-Hodgkin's lymphoma (NHL), 15 Hodgkin's disease (HD), two chronic myeloid leukaemia (CML) and three multiple myeloma (MM). Eleven patients could not collect the proposed threshold of CD34(+) cells. CY 4 mobilised patients recovered WBC counts in less days (P=0.03). By ANOVA, the days to WBC recovery had a linear function of the predictors "number of aphereses" and "type of mobilisation CT" (coefficients: 0.86 and 0.95, respectively). For the number of aphereses and WBC recovery after CT mobilisation, we obtained a correlation coefficient of 0.36 (P=0.02).
Conclusion: This study shows that it is feasible to mobilise and collect PBPC in patients previously treated with CT with or without RT. There was a linear correlation between the days for WBC recovery and the number of aphereses needed to collect the target number of CD34(+) cells. The study suggests that early WBC recovery, using mainly CY 4 mobilisation chemotherapy, is an important predictor of a low number of aphereses to achieve a good CD34(+) yield.