As shown in Figure 2a, for AML-MRD positive samples, red cells accounted for 0.0132% of nuclear cells in the O gate, expressing bright CD34, CD33, CD56, bright CD200, and bright CD13, but not expressing CD371, CD96, CD38, and HLA-DR, which were malignant myeloid primitive cells. The gene discussed is CD200; the disease is acute myeloid leukemia.