title: Characteristics of acute myeloid leukemia without HLA-DR expression.
abstract: BACKGROUND
  HLA-DR negativity is known to be useful for distinguishing acute promyelocytic leukemia (APL) from other subtypes of AML, but non-APL cases without HLA-DR antigen expression have been reported. The purpose of this study was to evaluate and compare the characteristics of APL, HLA-DR negative non-APL, and HLA-DR positive non-APL cases.
  
  
  METHODS
  A total of 114 cases of AML admitted at Ewha Womans University, Mokdong Hospital between March 1997 and June 2006 were included in this study. A diagnosis of AML was made based on the results of morphology, cytochemistry, immunophenotype, cytogenetics, and/or fluorescence in situ hybridization.
  
  
  RESULTS
  Among the 114 AML patients, HLA-DR antigen was not expressed in 39 (34%), including 24 non-APL (62%) and 15 APL patients (38%). The HLA-DR negative non-APL group showed higher leukocyte counts and positive rate of CD19 expression than did APL group (P<0.05). The remaining laboratory findings were not statistically different between the HLA-DR negative non-APL and APL groups. CD34 expression was more frequent in the HLA-DR positive non-APL group than in the HLA-DR negative non-APL group and APL group. Of the 24 patients with HLA-DR negative non-APL, 7 patients had disseminated intravascular coagulation and 2 patients showed morphologic features similar to those of APL.
  
  
  CONCLUSIONS
  CD19 expression and leukocyte count may be helpful for differentiating HLA-DR negative non-APL from APL. However, the final diagnosis and classification should be confirmed by cytogenetic or molecular studies.
authors: Department of Laboratory Medicine, School of Medicine, Ewha Womans University, Seoul, Korea.
authors: Heewon
authors: H
authors: Moon
authors: Sookyoung
authors: S
authors: Lee
authors: Jungwon
authors: J
authors: Huh
authors: Wha Soon
authors: WS
authors: Chung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018941:Antigens, CD19 / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006684:HLA-DR Antigens / Q000378:metabolism*; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis* / Q000473:pathology; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D018941:Antigens, CD19; D018952:Antigens, CD34; D006684:HLA-DR Antigens