Identification of the CD33‐related Siglec receptor, Siglec‐5 (CD170), as a useful marker in both normal myelopoiesis and acute myeloid leukaemias

• Published in: British journal of haematology 2003-11, Vol.123 (3), p.420-430
• Main Authors: Virgo, Paul, Denning‐Kendall, Patricia A., Erickson‐Miller, Connie L., Singha, Sakon, Evely, Roger, Hows, Jill M., Freeman, Sylvie D.
• Format: Article
• Language: English
• Subjects: Acute Disease; acute leukaemia; Adolescent; Adult; Aged; Aged, 80 and over; Antibodies - blood; Antibodies - therapeutic use; Antigens, CD - analysis; Antigens, CD - immunology; Antigens, CD34 - analysis; Antigens, Differentiation, Myelomonocytic - analysis; Antigens, Differentiation, Myelomonocytic - immunology; Biological and medical sciences; Biomarkers - analysis; Bone Marrow Cells - immunology; Case-Control Studies; CD33; Cell Differentiation - immunology; Child; Flow Cytometry; Fluorescent Antibody Technique; Hematologic and hematopoietic diseases; Hematology; Humans; Immunization, Passive; Infant, Newborn; Lectins - analysis; Lectins - immunology; Leukemia, Myeloid - immunology; Leukemia, Myeloid - therapy; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Medical sciences; Middle Aged; myelopoiesis; Myelopoiesis - immunology; Sialic Acid Binding Ig-like Lectin 3; Siglec; Stem Cells - immunology
• ISSN: 0007-1048; 1365-2141
• DOI: 10.1046/j.1365-2141.2003.04625.x

Sialic acid‐binding immunoglobulin‐like lectin (Siglec)‐5 or CD170 is a CD33‐related receptor, containing cytoplasmic immune receptor‐based tyrosine signalling motifs, that has previously been reported to be myeloid‐specific like CD33 and thus may be useful in the characterization of both normal and malignant haemopoiesis. This study showed that Siglec‐5 had a distinct expression pattern to CD33 both on normal myeloid cells and in acute myeloid leukaemia (AML). In normal bone marrow and cord blood, myeloid cells predominantly expressed Siglec‐5 at the later stages of granulocytic differentiation. Siglec‐5 was not expressed at significant levels by CD34+ progenitors either from bone marrow or mobilized peripheral blood. During in vitro myeloid differentiation of cord blood purified CD34+ cells, Siglec‐5 was upregulated later than CD33. Siglec‐5 expression remained absent or very low on cultured CD34+ cells, unlike CD33, which was present on almost all CD34+ cells by day 4. However, analysis of blasts from 23 patients with AML revealed aberrant expression of Siglec‐5 with CD34 in 50% (seven of 14) of patients with CD34+ AML; 61% (14 of 23) of AML cases were positive for Siglec‐5 with an increased frequency in the French–American–British subtypes M3‐5 (80%) compared with M0‐2 (25%). All 13 acute lymphoblastic leukaemic (ALL) samples tested, including a CD33+ ALL, were Siglec‐5 negative. These results support the further evaluation of Siglec‐5 antibodies in the diagnosis and monitoring of AML.