Figure 5. Immunohistochemical staining of peripheral blood leukocytes (PBLs) from allo-HSCT patients using mAbs ZJU-FH6 and ZJU-FE6. Cells stained dark brown were considered to be positive (arrows), and those stained blue were negative. Staining score was calculated as the number of positive cells/5 × 10⁴ WBC.