title: Expression of immune inhibitory receptor ILT3 in acute myeloid leukemia with monocytic differentiation.
abstract: BACKGROUND
  The diagnosis of AML with monocytic differentiation is limited by the lack of highly sensitive and specific monocytic markers. Immunoglobulin-like transcript 3 (ILT3) is an immune inhibitory receptor expressed by myelomonocytic cells and at high levels by tolerogenic dendritic cells.
  
  
  METHODS
  Using flow cytometry, we analyzed the expression of ILT3 in 37 patients with AML and 20 patients with no detectable disease.
  
  
  RESULTS
  We showed that ILT3 was expressed in all cases of AML displaying monocytic differentiation (FAB M4/M5; N = 18), but not in AML M1/M2 and M3 (N = 19; P < 0.0001). Co-expression of ILT3 and immature cell markers, such as CD34 and CD117, was observed in monoblastic leukemia. ILT3 expression was preserved after treatment in M4/M5 patients with refractory or relapsed disease. ILT3 expression was associated with the presence of cytogenetic abnormalities linked to an intermediate prognosis (P = 0.001). Rare CD45dimCD34+CD117+ILT3+ cells were identified in noninvolved bone marrow, suggesting that ILT3 expression is acquired at an early stage by normal myelomonocytic precursors.
  
  
  CONCLUSIONS
  ILT3 is a highly sensitive and specific marker which distinguishes AML with monocytic differentiation from other types of AML. Testing of ILT3 expression should be incorporated into the initial diagnostic work-up and monitoring of patients with AML.
authors.affiliation: Department of Pathology and Cell Biology, Columbia University Medical Center and New York Presbyterian Hospital, New York, New York, USA.
authors.forename: Hanna
authors.initials: H
authors.lastname: Dobrowolska
authors.forename: Kamraan Z
authors.initials: KZ
authors.lastname: Gill
authors.forename: Geo
authors.initials: G
authors.lastname: Serban
authors.forename: Elena
authors.initials: E
authors.lastname: Ivan
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Pengyuan
authors.initials: P
authors.lastname: Qiao
authors.forename: Nicole
authors.initials: N
authors.lastname: Suciu-Foca
authors.forename: David
authors.initials: D
authors.lastname: Savage
authors.forename: Bachir
authors.initials: B
authors.lastname: Alobeid
authors.forename: Govind
authors.initials: G
authors.lastname: Bhagat
authors.forename: Adriana I
authors.initials: AI
authors.lastname: Colovai
mesh_terms: D000328:Adult; D018952:Antigens, CD34 / Q000378:metabolism; D002454:Cell Differentiation; D003713:Dendritic Cells / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007948:Leukemia, Monocytic, Acute / Q000378:metabolism; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins; D008875:Middle Aged; D009000:Monocytes; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011971:Receptors, Immunologic
chemical_list: D018952:Antigens, CD34; C107907:LILRB4 protein, human; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D019009:Proto-Oncogene Proteins c-kit