Background: The gold standard for estimation of Hematopoietic Progenitor Cells (HPC), to determine the Time-To-Initiate Harvest (TTIH) and Adequacy-Of-Harvest Dose (AOHD) is Flow cytometric CD34 cell enumeration. However, flowcytometer is available at very few centers in India, is expensive, requires trained staff and is time-consuming. The Sysmex XN-9000 cell-counter provides HPC count which is the count of immature and blast cells in a sample. Cell-counters are more widely available, cheaper, easy to perform and gives quicker results.
Aims: We have evaluated the correlation of HPC, Mono-Nuclear Cell (MNC) and White Blood Cell (WBC) count with flow cytometric CD34 cell enumeration at our center in 114 samples from data available from January 2016 to June 2018.
Methods: The gold standard for HPC count is flow cytometric CD34 cell enumeration. HPC count was estimated by XN-9000 in White Precursor Cell (WPC) channel which detects the abnormal membrane composition and nuclear content. HPCs are relatively resistant to permeabilization by WPC reagent. Samples were run simultaneously to determine the HPC count by flowcytometer and cell counter.
Results: 114 samples were evaluated. The correlation coefficients (r) for HPC, MNC, WBC counts and flow cytometric CD34 cell enumeration were 0.850, 0.649 and 0.422 respectively.
Conclusion: As the correlation between the HPC count and flow cytometric CD34 cell enumeration is very strong, we could use HPC count to estimate TTIH and AOHD in HPC (A). The correlation of MNC count with flow cytometric CD34 cell enumeration is good, so at places where advanced automated cell counters are not available, MNC count can serve as a supplementary method to determine TTIH. In a resource constrained country like India where flowcytometers are not available everywhere, HPC could replace or serve as an adjuvant to flow cytometric CD34 cell enumeration.
