Diagnostic and Prognostic Value of CD123 in Acute Leukemia

Abstract
Background: Abnormalities of the alpha-chain of the interleukin-3 receptor (IL-3RA or CD123) are frequently observed in some leukemic disorders and may contribute to the proliferative character of leukemic cells.
Aims of Study: To study the role of CD123 expression in diagnosis of acute leukemia and correlation with other well established immunophenotyic markers of AML and ALL and evaluate its prognostic impact on outcome of acute leukemic patients.
Patients and Methods: The percentage of CD123 (+) cells in the blast population was determined at diagnosis using flow cytometry; expression >20% was considered positive. Thirty two adult patients with acute myeloid leukemia were included in the study. Correlations of CD 123 with expression of CD34, CD117, CD33, CD13, BM blast percentage and for AML outcomes as remission status at the end of the induction, 6 months overall survival were evaluated.*Twenty eight patients with acute lymphoblstic leukemia were included in the study. Correlations of CD123 with expression of CD34, CD 10 and CD 19 for ALL outcomes as remission status at the end of the induction, 6 month overall survival were evaluated.
Results: Regarding AML: Median age at diagnosis was 40.5 years (range 17-80 years), females were 18 (56.3%). CD123 expression was positive in 19 (59.4%); median ex-pression was 23.5% (range 10-87%). There were positive correlation between CD123 and CD117 (strong) {r=0.8, p= 0.00} and CD34 (moderate){r=0.5, p=0.02}. CD123 was correlated strongly positive with BM blast percent at diagnosis (r=0.5, p=0.00).CD123 +ve AML patients showed poor re-sponse to induction chemotherapy not getting CR (84.2%) vs CD123-ve AML (53.8%); p=0.06. With median follow-up 6 months, 2 patients relapsed; both were CD123 positive. Five patients died, all were CD123 positive. Regarding ALL: Median age at diagnosis was 28 years (range 1-78 years); out of 28 patients, 6 (21.4%) were pediatrics (<18 years) and 22 (78.6%) adults. Patients with B-ALL were 12 (42.9%) while T-ALL 16 (57.1%). CD123 expression was positive in 7/28 (25%); all of them were B-ALL vs. (0%) T-ALL; p=0.001. Mean of CD123 expression was higher in B-ALL vs. T-ALL, (p=0.002). CD123 +ve B-ALL patients not getting CR (71.4%) vs. CD123-ve B-ALL (20%). With median follow-up 6 months, one patient relapsed was CD 123 positive. Seven patients died, four were CD123 positive (57.1%).
Conclusion: *CD123 +ve AML patients showed poor response to induction chemotherapy vs. CD123 –ve AML patients. *High expression of CD123, CD34 and CD117 antigen could be a high negative factor for prognosis.