Defining the regions R1, R2 and R3 in flow-cytometric dot plots for MRD detection. a) Forward Scatter (FSC) vs. Side Scatter (SSC) in linear mode, showing the region gated for lymphoblasts (400–600), designated as R1. b) Lymphoblasts (R1) plotted with PE-(CD10/CD34 for B-ALL and CD7 for T-ALL) vs. SSC. The R2 gate indicates lymphoblasts positive for the PE tagged fluorophore. c) Cells in the R2 region are represented in this plot for detecting cells, which are positive for FITC-Achatinin-H (OAcSGP+) and PerCP-CD19/CD3 for B/T ALL using a multiple gate (R1+R2). Thus the R3 region gates lymphoblasts positive for all the three cell surface markers ensuring that every cell in this region is OAcSGP+CD10+CD19+or OAcSGP+CD34+CD19+ or OAcSGP+CD7+CD3+ and is defined as the region positive for MRD i.e., cells in this region are the residual blasts.
Chowdhury et al. BMC Cancer 2008 8:40 doi:10.1186/1471-2407-8-40