Initial white blood cell kinetics for assessment of individual response to the conditioning regimen in pediatric hematopoietic stem cell transplantation patients

Abstract

We hypothesized that the individual hematological response to chemo/ radiotherapy may be used as a parameter to assess the degree of myeloablation and probability of transplant-related events. This study included 58 pediatric patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT). White blood cell (WBC) ratio (pre-conditioning WBC: day 0 WBC), day 0 WBC count, and WBC nadir day were used as potential indicators of myeloablation. The association between WBC kinetics and clinical result of HSCT was investigated. There was a positive correlation between WBC ratio and the date of engraftment. A positive correlation was noted between day 0 WBC count and engraftment day. There was a negative correlation between WBC nadir day and engraftment day. WBC nadir day was lower in patients with acute graft-versus-host disease (GVHD) than in cases without acute GVHD. Among patients who had fever during the conditioning regimen, the WBC ratio was higher, day 0 WBC count was lower, and WBC nadir day was lower in patients who developed >5 days of fever between day 0 and day +30. The present preliminary study suggests that WBC kinetics may be used as a measure of initial hematological response to the conditioning regimen and perhaps in determining the degree of myeloablation.