Immunophenotypic Modulation of the Blast Cells in Childhood Acute Lymphoblastic Leukemia Minimal Residual Disease Detection

Abstract

Early clearance of leukemic cells during induction therapy of childhood acute lymphoblastic leukemia (ALL) is a basis for treatment optimization. Currently, the most widely used methods for the detection of minute residual malignant cells in the bone marrow and/or peripheral blood, minimal residual disease (MRD), are PCR and flow cytometry (FCM). Immunophenotypic modulation (IM) is a well known factor that can hamper the accurate FCM analysis.Aim: To report the IM detected by 8-color FCM during the BFM-type remission induction in 24 consecutive MRD-positive samples of children with B-cell precursor ALL and the possible implications for MRD detection.Patients and methods: Between 2010 and 2012 we prospectively followed up the MRD on days 15 and 33 of induction treatment in bone marrow (BM) samples and on day 8 in peripheral blood (PB). The IM was assessed by comparative analyses of the changes in the mean fluorescence intensity of 7 highly relevant antigens expressed by the leukemic cells and normal B-lymphocytes.Results: IM occurred, to different extents, in all analyzed day 15 BM and in most day 33 BM samples. Statistically significant changes in the MFI-levels of four CDs expressed by the leukemic blasts were observed: downmodulation of CD10, CD19 and CD34 and upmodulation of CD20. No changes in the expression of CD38, CD58 and CD45 were noticed.Conclusions: Measuring the MRD by standardized 8-color flow cytometry helps improve the monitoring of the disease, leading to better therapeutic results. However, the IM of the different antigens expressed by the leukemic blasts should be taken into consideration and cautiously analyzed.

A reproducible strategy for analysis of minimal residual disease measured by Standardized multiparametric flow cytometry in b acute lymphoblastic leukemia

“…However, we could observe a significant variation of intensity in marker expression when compared to the original leukemic population, with particular mention, the decrease of intensity of CD10, CD66c, or CD34 and increase of intensity of CD20, CD10, and CD21. Similar findings have been reported by others researchers . .…”

“…Second, despite the unquestionable advantages of using the standardized bulk lysis technique, it remains questionable that changes in sample preparation procedures could interfere with the correct interpretation of immunophenotypic changes or modify critical features in selected cell populations. Immunophenothypic modulation of the leukemic cells and normal B residual cells during chemotherapy should be taken into consideration and cautiously analyzed to interpret the FC‐MRD experiments .…”

Endoglin: a novel target for therapeutic intervention in acute leukemias revealed in xenograft mouse models

“…Nine deidentified primary samples from B-ALL and AML patients were evaluated ( Table 1). The blast population was gated based on side scatter (SSC) and low/intermediate expression of CD45, and then analyzed for the expression of CD34 and CD38 to confirm the immature phenotype, [28][29][30] CD19 or CD117 (to confirm B-ALL or AML phenotype, respectively), and CD105 (supplemental Figure 2; Table 1). CD105 was highly expressed on the majority of B-ALL blasts, and varying from 47.5% to 98.5% in AML blasts (Table 1; Figure 1B), indicating that CD105 is expressed on myeloid and B-lymphoid leukemic blasts.…”

Immunophenotypic shift in the B‐cell precursors from regenerating bone marrow samples: A critical consideration for measurable residual disease assessment in B‐lymphoblastic leukemia

“…The therapy-related immunophenotypic shift of antigen expression in B-ALL residual blasts has already been reported. (Burnusuzov et al, 2016;Dworzak et al, 2010;Pawinska-Wasikowska & Balwierz, 2010;Szczepa nski et al, 2006;Tembhare et al, 2018) It from the usual immunophenotypic signature of TNSCs. With the high-sensitivity analysis, we evaluated a higher number of BCPs (1330-1,416,514 events in the "non-PC CD19+ B cell" gate) that allowed us to document the immunophenotypic changes seen in regenerative BCPs comprehensively.…”

“…mainly highlights the downregulation of CD34 and CD10, upregulation of CD19, CD20, and CD45 (Burnusuzov et al, 2016;Dworzak et al, 2010;Pawinska-Wasikowska & Balwierz, 2010;Tembhare et al, 2018; . Tembhare et al, 2020) Gaipa et al have reported the reduction of CD10 and CD34 expression in prednisone-treated B-ALL blasts in cell culture and confirmed the steroid-induced immunophenotypic shift in leukemic blasts of B-ALL(Theunissen, Sedek, et al, 2017).…”