Gating strategy for detection of circulating hematopoietic progenitor cells (HPCs) on the basis of ISHAGE guidelines. The top panels (A-D) represent a patient with AMI at T0 stained with anti-CD45–FITC (FL1-H) and anti-CD34–PE (FL2-H). The bottom panels (E-H) show the same sample using an isotype control for anti-CD34. We first counted 200 000 CD45⁺ cells (A,E). From this primary gate, HPCs were identified by means of additional expression of CD34 (B,F). The CD45 antigen expression (C,G) and the characteristic light-scatter properties (D,H) are shown.