[1605] Plasmacytoid Dendritic Cell Marker CD123 Alone Does Not Have Prognostic Value in Acute Myeloid Leukemia (AML)

Da Zhang, Lindsay Blick, Mark Davis, Wei Cui, Mark T Cunningham. University of Kansas Medical Center, Kansas City, KS; University of Massachusetts Medical School, Worcester, MA

Background: CD123 is the alpha-chain of the IL-3 receptor, a member of the cytokine receptor superfamily and a human plasmacytoid dendritic cell precursors marker. CD123 promotes cell survival, proliferation, and prevents cell death by apoptosis via interaction with IL-3. Blastic plasmacytoid dendritic cell neoplasm is a clinically aggressive tumor derived from the precursors of plasmacytoid dendric cells which express CD123. To evaluate plasmacytoid dendritic cell marker CD123 expression and its prognostic value in AML, we analyzed a total of 62 acute myeloid leukemia cases over a 12 month period.
Design: We obtained specimens with informed consent at the University of Kansas Medical Center by following an institutional review board approved protocol. A total of 62 acute myeloid leukemia flow cytometry data were collected and reviewed. Differences between two independent mean values were tested for statistical significance using the two-tailed t-test.
Results: Out of 62 AML cases, eleven cases (17.7%) had high level CD123 expression ranging from 20% up to 84%. Eighteen cases (29.0%) had low level CD123 expression ranging from 5% to 18%. Low or high level CD123 expression was associated with the absence of certain myeloid markers (CD13, CD33, CD34, CD117 and HLA-DR) and the presence of CD7; however, CD123 was not associated with CD4 and CD56 co-expression in this study. There is no statistical significant between CD123 positive and negative group in term of cytogenetic prognostic classification, survival, and status of FLT3 or NPM mutations.
Conclusions: In this study, the expression of CD123 in AML is not associated with either FLP3 or NPM1 status or any statistical significance between the CD123 positive group and the CD123 negative group AML in term of genetic prognostic classification, except CD7 expression in high level expression of CD123 AML group. CD123 expression alone in AML does not have prognostic value. Contrast to previous study, which showed 93% of AML cases had 20% or more CD123 coexpression, we only observed 17.7% of our AML cases had 20% or more CD123 coexpression with blasts and 29% of our cases had a low level of CD123 coexpression (≥5% to 18%). The total cases of 5% or more CD123 positive population AML was only 46.7%, much lower than previous study. These differences is unclear, may be due to the anti-CD123 monoclonal antibodies used, the definition of a positive cell, or the patient population.
Category: Hematopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 221, Tuesday Morning


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