Novel way to count hematopoietic stem cell
Stem cell transplantation is one of the last considerations for blood cancer patients who are not eligible to go through chemotherapy. According to the EBMT guidelines, 2 x 10^6 cells/kg is considered the minimum number of cells needed for autologous stem cell transplantation while 4 x 10^6 cells/kg is for allogeneic transplantation.[1] The enumeration device which can accurately enumerate the number of cells to meet the minimum requirement for stem cell is necessary.
Indisputably, flow cytometry is the gold standard for stem cell enumeration. It requires antibody staining of CD45 and CD34, and gating under ISHAGE protocol. ISHAGE protocol is widely applied to minimize the discrepancy between the users. Though ISHAGE protocol has established consistency for gating procedures, as it needs to be done manually, it is prone to human error. The article, ’ISHAGE protocol: Are we doing it correctly?’ questioned whether the ISHAGE protocol is used in an appropriate manner.[2]
What is ADAMII CD34?
ADAMII CD34 is a novel way to measure CD34+ stem cells. Unlike flow cytometry which requires sheath fluid to run the system, ADAMII CD34 is an image-based CD34+ stem cell counter free from gating, buffer, maintenance, and washing. Except for the difference in result interpretation algorithm, as shown in the figure 1, the overall process of staining and lysis is exactly the same with FACS, therefore providing exactly the same parameters: total CD45, viable CD45, total CD34, viable CD34, but in a more convenient way.
The key difference between ADAMII CD34 and flow cytometry is that flow cytometry needs to perform gating to select cells. ADAMII CD34 is a factory calibrated machine with easy auto-focus and automated counting that the user does not need gating. As ADAMII CD34 does not require gating, one of the frequently asked questions is then how to apply ISHAGE protocol for ADAMII CD34? ADAMII CD34 is validated with FACS which is measured under ISHAGE protocol. Therefore, even without gating, the value calculated by ADAMII CD34 will give comparable results to that of FACS applied with ISHAGE protocol.
Up to date, ADAMII CD34 is the only in vitro diagnostic approved image-based CD34 stem cell counter with both FDA 510 (k) clearance and CE approval (figure 2). Currently, ADAMII CD34 is under validation in several countries simultaneously. Recently, in October, 2 posters were published in the German Society for Transfusion Medicine and Immunohematology by DKMS and German Red Cross. Through NanoEntek Blog, we aim to share the science and the latest news about ADAMII CD34 which was not covered in linkedin promotion.
References:
1.Sureda et al. (eds.) The EBMT Handbook, https://doi.org/10.1007/978-3-031-44080-9_16
2. Alison Whitby et al. Cytometry B Clin Cytom. 2012 Jan;82(1):9-17. doi: 10.1002/cyto.b.20612. Epub 2011 Sep 13.
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