FCGR1A and acute myeloid leukemia: CD15 (3 alpha-fucosyl-N-Acetyl lactosamine), also called Lewis X or stage-specific embryonic antigen 1 (SSEA-1), is a carbohydrate antigen expressed on the majority of AML cells and on some NK cells, T cells, monocytes, neutrophils and eosinophils.52 CD15 expression on AML blast was associated with favorable prognosis such as continuous complete remission and longer survival.53 In an attempt to design a bispecific antibody, the fragment of antigen-binding (Fab) of an anti-CD64 antibody was chemically conjugated with whole IgM monoclonal antibody against CD15.