Higher infused CD34+ hematopoietic stem cell dose correlates with earlier lymphocyte recovery and better clinical outcome after autologous stem cell transplantation in non‐Hodgkin's lymphoma

Abstract

Lymphocyte recovery after autologous stem cell transplantation (ASCT) has been shown to be associated with positive clinical outcome in non-Hodgkin's lymphoma (NHL). This study sought to identify variables that affect lymphocyte recovery and survival after ASCT. A retrospective analysis of outcomes in 97 consecutive patients with NHL who underwent ASCT in a single center from August 1999 to January 2008 was conducted. A significant relationship was not observed between infused lymphocyte count and days to recovery of absolute lymphocyte count 500 x 10(6)/L or greater after ASCT (ALC500; r = 0.139, p = 0.176), but there was a significant inverse correlation between infused CD34+ cell count and days to ALC500 (r = -0.333, p = 0.001). Univariately, infused CD34+ cell count and recovery of ALC500 by 20th day after ASCT were significant predictors of survival. The median overall survival (OS) and event-free survival (EFS) were significantly longer in patients who received 8.2 x 10(6) CD34+ cells/kg or more than in those who received fewer than 8.2 x 10(6) CD34+ cells/kg (OS, not reached vs. 11.6 months, p = 0.001; EFS, not reached vs. 4.8 months, p = 0.003). Multivariate analysis confirmed that infused CD34+ cell count was an independent prognostic factor for OS (p = 0.017) and EFS (p = 0.002). These data suggest that infused CD34+ cell count is predictive of kinetics of lymphocyte recovery after ASCT and is an independent prognostic factor for OS and EFS after ASCT in patients with NHL.