{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"CD33 (gp67 or siglec-3) is a glycosylated transmembrane protein that is a member of the sialic acid-binding immunoglobulin-like lectin (siglec) family. The genomic locus of this protein has been mapped to chromosome 19q13.1-3.5. The function of CD33 is not known, but it may have a role in cell-to-cell adhesion. In maturing granulocytic cells, there is progressive down-regulation of CD33 from the blast stage to mature neutrophils. However, in monocytes and macrophages/histiocytes, strong expression of CD33 is maintained throughout maturation. CD33 expression is important in the immunophenotyping of acute leukemia according to literature."}]}]}