Immunophenotypic modulation in pediatric B lymphoblastic leukemia and its implications in MRD detection

Abstract

Minimal/Measurable residual disease (MRD) is the most reliable and powerful indicator of prognosis in B cell precursor acute lymphoblastic leukemia (BCP-ALL). Modulation of antigenic expression in leukemic cells is known to occur postchemotherapy and thus carries a potential risk of false MRD quantification by flowcytometry. We studied the immunophenotypic modulation of nine antigens in residual leukemic cells at postinduction MRD assessment in 31 BCP - ALL children. We found significant downmodulation of CD10, CD38, CD58, CD81 and upmodulation of CD19, CD45 in leukemic cells. Downmodulation of CD34 was observed but was not statistically significant. Expression of CD20 and CD22 remained stable in most of the cases. MRD-positive cases showed loss of diagnostic LAIP and some showed gain of new LAIP compared to baseline. Various combination of antibodies including the novel markers should be incorporated into the panel to increase the sensitivity of MRD detection.

Keywords:

• Acute lymphoblastic leukemia
• minimal residual disease
• flow cytometry
• immunophenotypic modulation
• chemotherapy

Acknowledgements

We would like to acknowledge Mr Selvaraj, Junior technical officer, Department of Hematology for his efforts in sample processing, acquisition and data retrieval. We would also like to acknowledge Ms. Mirunalini, Secretary, Department of Hematology for data retrieval.

Disclosure statement

The authors report no conflict of interest.