Abstract
Hematopoietic recovery is considered to be associated with the number of multipotent hematopoietic stem cells in the bone marrow, as observed in functional assays involving stem cell transplantation. However, there is little evidence related to hematopoietic recovery in non-transplantation settings, which is accomplished by endogenous hematopoietic cells. A recent study suggested that progenitors are the main contributors during this steady-state hematopoiesis, which differs from exogenous transplantation. We hypothesized that endogenous progenitor support post-chemotherapy hematopoietic recovery. To investigate the potential impact of these progenitor cell percentage on hematopoietic recovery, we retrospectively analyzed the percentage of CD34+CD38+CD117+HLA-DR+CD13+CD33+ cells (P cells) and hematopoietic recovery in 223 newly diagnosed acute myeloid leukemia patients during two courses of consolidation chemotherapy after complete remission. We found that a lower P cell percentage was significantly associated with prolonged neutropenia recovery time after the first and second courses of consolidation chemotherapy (p = 0.001; p = 0.045, respectively). We also observed similar results with regard to platelet recovery time after the first course of consolidation chemotherapy (p = 0.000). Univariate analysis showed that P cell percentage and consolidation chemotherapy regimens, and not gender, age, induction chemotherapy regimens, infection grade, WHO classification and NCCN risk category, were associated with neutrophil recovery after chemotherapy. Multivariate analysis demonstrated that P cell percentage is an independent factor affecting neutrophil recovery capacity for both the first and second courses (p = 0.008; p = 0.032, respectively). Our results indicate that CD34+CD38+CD117+HLA-DR+CD13+CD33+ cells before each course of chemotherapy is independently associated with chemotherapy-related hematopoietic reconstitution capacity. These findings may help modify future chemotherapy regimens based on progenitor cell percentages.