Correlation Between Survival and Number of Mobilized CD34+ Cells in Patients with Multiple Myeloma or Waldenström Macroglobulinemia

High-dose chemotherapy followed by autologous stem cell transplantation is the established treatment for symptomatic multiple myeloma (MM) or Waldenström macroglobulinemia (WM). We retrospectively analyzed the impact of mobilized CD34+ cell number on clinical outcomes in patients with MM or WM who underwent autologous stem cell transplantation in our hospital from 1997 to 2007. A total of 39 patients were identified. All patients received peripheral stem cell support after a conditioning regimen. We defined patients with collection of a large number (≥ 8 × 10⁶/kg) of CD34+ cells as super mobilizers (SM), and all others as normal mobilizers (NM). Although hematological engraftment was earlier in the SM group, overall survival did not differ significantly between groups (P = 0.392). Likewise, no significant differences were seen in progression-free survival (P = 0.201) or survival after relapse (P = 0.330). In conclusion, our retrospective study could not find any correlation between survival and number of mobilized CD34+ cells, in contrast to previously reported results.