Publications by authors named "Paola Pacelli"

3 Publications

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Minimal Residual Disease in Multiple Myeloma: State of the Art and Applications in Clinical Practice.

J Pers Med 2020 Sep 10;10(3). Epub 2020 Sep 10.

Division of Hematology, University of Siena, 53100 Siena, Italy.

Novel drugs have revolutionized multiple myeloma therapy in the last 20 years, with median survival that has doubled to up to 8-10 years. The introduction of therapeutic strategies, such as consolidation and maintenance after autologous stem cell transplants, has also ameliorated clinical results. The goal of modern therapies is becoming not only complete remission, but also the deepest possible remission. In this context, the evaluation of minimal residual disease by techniques such as next-generation sequencing (NGS) and next-generation flow (NGF) is becoming part of all new clinical trials that test drug efficacy. This review focuses on minimal residual disease approaches in clinical trials, with particular attention to real-world practices.
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September 2020

Flow Cytometry Assessment of CD26 Leukemic Stem Cells in Peripheral Blood: A Simple and Rapid New Diagnostic Tool for Chronic Myeloid Leukemia.

Cytometry B Clin Cytom 2019 07 3;96(4):294-299. Epub 2019 Feb 3.

Hematology Unit, Azienda Ospedaliera Universitaria Senese, Siena, Italy.

Background: Recent investigations in chronic myeloid leukemia (CML) have focused on the identification and characterization of leukemic stem cells (LSCs). These cells reside within the CD34 /CD38 /Lin fraction and score positive for CD26 (dipeptidylpeptidase IV) a marker, expressed in both bone marrow (BM) and peripheral blood (PB) samples, that discriminates CML cells from normal hematopoietic stem cells (HSCs) or from LSCs of other myeloid neoplasms. CD26 evaluation could be a useful tool to improve the identification of CML LCSs by using flow-cytometry assay.

Methods: CD26 LSCs have been isolated from EDTA PB and BM samples of patients with leucocytosis suspected for CML. Analysis of LSCs CML has been performed by using custom-made lyophilized pre-titrated antibody mixture test and control tube and a CD45 /CD34 /CD38 /CD26 panel as a strict flow cytometric gating strategy.

Results: The expression of CD26 on CD34 /CD38 population was detectable in 211/211 PB and 84/84 BM samples of subsequently confirmed BCR-ABL CP-CML patients. None of the 32 samples suspicious for CML but scoring negative for circulating CD26 LSCs were diagnosed as CML after conventional cytogenetic and molecular testing. To validate our results, we checked for PB CD26 LSCs in patients affected by other hematological disorders and they all scored negative for CD26 expression.

Conclusions: We propose flow cytometry evaluation of CD26 expression on PB CD34 /CD38 population as a new rapid, reproducible, and powerful diagnostic tool for the diagnosis of CML. © 2019 The Authors. Cytometry Part B: Clinical Cytometry published by Wiley Periodicals, Inc. on behalf of International Clinical Cytometry Society.
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July 2019

Residual Peripheral Blood CD26 Leukemic Stem Cells in Chronic Myeloid Leukemia Patients During TKI Therapy and During Treatment-Free Remission.

Front Oncol 2018 30;8:194. Epub 2018 May 30.

Hematology Unit, Department of Medicine, Surgery and Neuroscience, Azienda Ospedaliera Universitaria Senese, University of Siena, Siena, Italy.

Chronic myeloid leukemia (CML) patients in sustained "deep molecular response" may stop TKI treatment without disease recurrence; however, half of them lose molecular response shortly after TKI withdrawing. Well-defined eligibility criteria to predict a safe discontinuation up-front are still missing. Relapse is probably due to residual quiescent TKI-resistant leukemic stem cells (LSCs) supposedly transcriptionally low/silent and not easily detectable by BCR-ABL1 qRT-PCR. Bone marrow Ph+ CML CD34/CD38 LSCs were found to specifically co-express CD26 (dipeptidylpeptidase-IV). We explored feasibility of detecting and quantifying CD26 LSCs by flow cytometry in peripheral blood (PB). Over 400 CML patients (at diagnosis and during/after therapy) entered this cross-sectional study in which CD26 expression was evaluated by a standardized multiparametric flow cytometry analysis on PB CD45/CD34/CD38 stem cell population. All 120 CP-CML patients at diagnosis showed measurable PB CD26 LSCs (median 19.20/μL, range 0.27-698.6). PB CD26 LSCs were also detectable in 169/236 (71.6%) CP-CML patients in first-line TKI treatment (median 0.014 cells/μL; range 0.0012-0.66) and in 74/112 (66%), additional patients studied on treatment-free remission (TFR) (median 0.015/μL; range 0.006-0.76). Notably, no correlation between BCR-ABL/ABL ratio and number of residual LSCs was found both in patients on or off TKIs. This is the first evidence that "circulating" CML LSCs persist in the majority of CML patients in molecular response while on TKI treatment and even after TKI discontinuation. Prospective studies evaluating the dynamics of PB CD26 LSCs during TKI treatment and the role of a "stem cell response" threshold to achieve and maintain TFR are ongoing.
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May 2018