Effect of RBC lysing solution on CD34(+) cell counting]

To investigate whether the RBC lysing solution can affect the results of relative enumeration of CD34(+) cells, 37 mobile peripheral blood apheresis products were stained using CD34-PE and CD45-FITC monoclone antibodies and RBCs were then lysed by two lysing solution commercially available (one named FACS Lysing Solution, FACS; another IOTest 3 Lysing Solution, IOTest) and one lysing solution self-prepared. After being processed by lyse-and-then-washed method, samples were detected by FACSC anto flow cytometer. The percentages of CD34(+) cells were determined based on ISHAGE gating strategy, forward and side scatter (FSC and SSC) characteristics, percentage of CD45(+) cells were recorded simultaneously. The results showed that by lyse-and-then-wash method, the percentages of CD34(+) cells in FACS-treated samples were significantly lower compared with that in IOTest-treated samples (0.50 +/- 0.42 vs 0.92 +/- 0.59, p = 0.004), but no statistical difference was observed between IOTest-treated and ourselves-prepared-treated samples. The intensities of FSC and SSC in cells of IOTest-treated sample were significantly higher compared with that in cells of FACS-treated sample (p < 0.01). The proportion of CD45(+) cells in IOTest-treated samples was lower than that in FACS-treated samples. The WBC count of samples was not correlated to the amount of CD34(+) cells (r(s) = 0.192, p = 0.357). It is concluded that the red cell lysing solution shows unexpected effect on detecting and counting CD34(+) cells, prudence should be taken to select such reagents at FCM performance.