CD123 expression levels in 846 acute leukemia patients based on standardized immunophenotyping

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• CD123 expression is known on plasmacytoid dendritic cells but scarce and difficult to compare in acute leukemia due to varied methodologies.
• Standardized data on CD123 expression across different acute leukemia subtypes is needed for clinical applications.

Purpose of the Study:

• To evaluate CD123 expression in a large cohort of pediatric and adult acute leukemia patients using a standardized immunophenotyping method.
• To establish a reliable reference for CD123 expression in various acute leukemia subtypes and compare it with leukemic stem cells and diagnosis-relapse samples.

Main Methods:

• Utilized standardized EuroFlow immunophenotyping to assess CD123 expression in 139 pediatric AML, 316 adult AML, 193 pediatric BCP-ALL, 69 adult BCP-ALL, 101 pediatric T-ALL, and 28 adult T-ALL patients.
• Analyzed paired diagnosis-relapse samples (57 AML, 19 BCP-ALL) and leukemic stem cell (LSC) data (32 pediatric AML).
• Quantified CD123 expression using mean fluorescence intensity, median fluorescence intensity, and percentage of CD123 positive cells.

Main Results:

• CD123 was expressed in the majority of AML and BCP-ALL, but absent in most T-ALL.
• In AML, CD123 expression varied with subtypes: lower in erythroid/megakaryocytic leukemia, higher in NPM1/FLT3-ITD mutated leukemia, and comparable between LSC and blasts.
• BCP-ALL showed higher CD123 expression in hyperdiploid karyotypes and with BCR-ABL fusion; expression increased at relapse, while AML relapse expression was variable.

Conclusions:

• Standardized methodology confirmed CD123 expression patterns across diverse acute leukemia subtypes.
• Results provide a crucial reference for CD123 expression in health and disease.
• This data can aid in stratifying patients for CD123-targeted therapies.