Usefulness of the IMI Channel of Sysmex SE-9000(TM) Automated Hematology Analyzer Predicting the Optimal Timing of Peripheral Blood Stem Cell Harvest

Lee, Seon Ju; Hong, Seong Geon; Baek, Jin Young; Kang, Myung Seo; Chong, So Young; Oh, Doyeon

Abstract

BACKGROUND: An essential prerequisite for successful procurement of sufficient peripheral blood stem cells (PBSC) for engraftment is the optimal timing of collection. The Sysmex SE-9000 automated hematology analyzer provides the immature information (IMI) channel for the identification and counting PBSC. In this study, The optimal timing of PBSC collection was studied using IMI channel.
METHODS
193 peripheral blood stem cell collections were performed from 52 patients with hematologic disorders or solid tumors and 15 donors. Pre-harvest peripheral blood WBC, mononuclear cells (MNC) and IMI were tested and compared with CD34+ cell count and CFU-GM count of harvested products.
RESULTS
Peripheral blood WBC and MNC count showed a weak correlation with CD34+ cell yield (r=0.38, P<0.0001 and r=0.38, P<0.0001) and peripheral blood IMI had a stronger correlation (r=0.58, P<0.0001) with collected CD34+cells than did WBC and MNC count. A receiver operating characteristic (ROC) curve was drawn for cutoff value of IMI and predictive values of the chosen cutoff value of IMI for different target CD34+ cell collections were calculated. The ROC curve showed that the best cutoff value of IMI was 465/microliter for the target CD34+ cells >1x10(6)/kg with sensitivity of 88.7%. Positive and negative predictive values of IMI >465/microliter for CD34+ cell >1x10(6)/kg were 65.5% and 87.5%, respectively.
CONCLUSIONS
The automated IMI might be used as a simple and efficient indicator of PBSC mobilization and applying variable cutoff values of IMI would be a useful tool to predict the optimal timing of PBSC collection.