Peripheral blood stem cell (PBSC) mobilization and transplantation after fludarabine therapy in chronic lymphocytic leukaemia (CLL): a report of the European Blood and Marrow Transplantation (EBMT) CLL subcommittee on behalf of the EBMT Chronic Leukaemias Working Party (CLWP).

We performed a survey from 122 centres of the European Group of Blood and Marrow Transplantation (EBMT) concerning peripheral blood stem cell (PBSC) mobilization after fludarabine treatment of patients with chronic lymphocytic leukaemia (CLL). A total of 101 leucaphereses from 29 patients was performed. The median cell numbers collected were: CD34+ cells, 2.2 x 106/kg (0.1-15.3); granulocyte-macrophage colony-forming units (GM-CFU), 4.29 x 104/kg (0.4-177); and mononuclear cells, 6.4 x 108/kg (1.3-63). In univariate and multivariate analyses, the numbers of cells collected were not significantly influenced by the nature of mobilizing regimen and there was a trend towards the collection of a higher number of CD34+ cells from patients who received fludarabine only before mobilization. There was a significant correlation between the median number of CD34+ cells collected and the number of courses of fludarabine (higher CD34+ cell numbers were related to more than six courses) and the interval between the last dose of fludarabine and the start of mobilizing therapy (higher CD34+ cell numbers were related to a delay > or = 2 months). Sixteen patients have subsequently undergone autologous transplantation and showed rapid engraftment. In conclusion, the results reported favour early stem cell mobilization in CLL patients who are in remission after first-line therapy. However, attention should be given to the timing of mobilization with respect to the time since the last dose of fludarabine.