Figure 1.

LILRB4 Is a Specific Marker for Monocytic AML that Displays Restricted Expression to Cells of Monocyte Lineage

(A) Flow cytometry plot of representative patient sample for monocytic AML (M5), gated from mid to large FSC, low to mid SSC and CD45-dim, demonstrating that LILRB4 is expressed in the full population of leukemia blasts. (B) Quantification of LILRB4 expression in 69 patients with AML demonstrating that LILRB4 is expressed on greater than 99% (SD = 1.25) of leukemia cells in all patients with monocytic AML. (C) Representative flow cytometry plot demonstrating that a sub-population of AML-M5 leukemia cells co-express LILRB4 and CD34. (D and E) Expression profile of LILRB4 in normal tissue at protein (D) and RNA (E) level was assessed by utilizing publicly available databases for mass-spectrometry proteomic analysis (Human Proteome Map: LILRB4; http://www.humanproteomemap.org/query.php) and gene expression (human body index-transcriptional profiling, GSE7307: 210152_at), respectively. (F) Representative images examining human LILRB4 expression by immunohistochemistry of liver (left) and brain tissue (right) (n = 8 samples/tissue). Sections of THP-1 AML tumor implants were used as positive (wild-type) and negative (LILRB4-knockout) control. Scale bars, 250 μm (top panels); 100 μm (bottom panels). (G) Flow cytometry analysis of LILRB4 expression (red) and isotype control (blue) on AML cell lines MV4-11, THP1, and MOLM13. Data are represented as mean ± SE.