CD34 and CD117 are overexpressed in AML and may be valuable to detect minimal residual disease

We estimated by quantitative flow cytometry (FC) the expression of CD13, CD33, CD34 and CD117 antigens in cells from 64 patients with acute myeloid leukaemia (AML) and 22 normal bone marrows (BMs). The method converts fluorescence intensity into number of antigen molecules per cell, measured by antibody binding capacity (ABC). The number of molecules per cell in normal BM was 9.5±5.7 for CD13, 7±2.3 for CD33, 6±0.7 for CD34, and 6.3±1.5×103 for CD117. AML blasts expressed 11.4±12.4 molecules per cell for CD13, 9.5±9.7 for CD33, 74±2328.5 for CD34 and 12.5±33×103 for CD117. The number of CD34 and CD117 molecules were significantly higher in AML than in normals (P<0.0001 and P