CD33 (Cluster of differentiation 33), also known as p67 or SIGLEC-3 (Sialic acid binding Ig-like lectin 3), is a type I transmembrane glycoprotein of 67kDa. It is a sialoadhesin molecule belonging to the immunoglobulin supergene family and SIGLEC family of lectins. CD33 is a myeloid cell surface antigen that is specific for the myeloid lineage, but it also can be found on certain lymphoid cells as a restricted leukocyte antigen. It is expressed on myeloid stem cells, myeloblasts, monoblasts, monocytes/macrophages, granulocyte precursors, and mast cells. CD33 is a remarkable myeloid marker and is commonly applied in the diagnosis of acute myeloid leukemia (AML). And 10% to 20% of B lymphoblastic or T lymphoblastic leukemia/lymphomas are likely to aberrantly express CD33. FcγRIII, synonymously also referred to CD16, is a type III Fcγ receptor which has other two identified members: a high-affinity receptor FcγRI (CD64) and a low-affinity one FcγRII (CD32). This transmembrane protein, FcγRIII, contains two extracellular immunoglobulin (Ig)-like domains with low-affinity for IgG. It is responsible for antibody-dependent cellular cytotoxicity. FcγRIII is expressed on large granular lymphocytes of both nature killer (NK)- and T-cell types. There are two different isoforms of it in humans named FcγRIIIa and FcγRIIIb, sharing 96% sequence identity in extracellular Ig binding regions. FcγRIIIa is a transmembrane receptor found on macrophages, mast and NK cells. FcγRIIIb is expressed exclusively on neutrophils and functions as the only Fc receptor anchored via a glycosyl-phosphatidylinositol (GPI) linker to the cell membrane. CD123 (Cluster of differentiation 123), also known as IL-3R or IL-3RA (Interleukin-3 (IL-3) receptor α-chain), is a membrane receptor belonging to the type I cytokine receptor family. This glycoprotein of 360 amino acids includes a predicted Ig-like domain, a transmembrane domain, an intracellular domain and two FnIII domains and can help transmit the signal of IL-3. The protein encoded by CD123 is an IL-3 specific subunit of a heterodimer composed of α- and β-chains. It is thought to be involved in cell signal transduction for the cell growth and differentiation. CD123 is normally expressed on monocytes, basophils, endothelial cells, and plasmacytoid dendritic cells. It is associated with the development of many diseases and considered as a novel marker in the clinical diagnosis.