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

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.

Unbiased pro-thrombotic features at diagnosis in 977 thrombocythemic patients with Philadelphia-negative chronic myeloproliferative neoplasms.

In patients with Philadelphia-negative chronic myeloproliferative neoplasms (MPNs), the anti-thrombotic and/or cytoreductive treatment in the follow-up may affect the evaluation of the pro-thrombotic weight of the clinical and biological characteristics at diagnosis. In order to avoid this potential confounding effect, we investigated the relationship between prior thrombosis (PrTh: thrombosis occurred before diagnosis and before treatment) and the characteristics at diagnosis in 977 thrombocythemic patients with MPN, reclassified according to the WHO 2008 criteria. PrTh occurred in 194 (19.9%) patients, with similar rates in the different MPNs. In multivariate analysis, PrTh rate was significantly related to minor thrombocytosis (platelets ≤700×10(9)/L), leukocytosis (leukocytes >10×10(9)/L), higher hematocrit (HCT >45%), JAK2 V617F mutation, older age, and cardiovascular risk factors (CVRFs). The highest PrTh rate (33.9%) was associated with the coexistence of minor thrombocytosis and leukocytosis. Of note, the inverse relationship between PrTh rate and platelet count is consistent with the hemostatic paradox of thrombocytosis. In conclusion, this analysis in MPN patients disclosed the unbiased characteristics at diagnosis with a pro-thrombotic effect. Moreover, it suggests that the optimal control of blood cells counts, and CVRFs might be of utmost importance in the prevention of thrombosis during the follow-up.

Induction chemotherapy strategies for primary mediastinal large B-cell lymphoma with sclerosis: a retrospective multinational study on 426 previously untreated patients.

BACKGROUND AND OBJECTIVES: This multinational retrospective study compares the outcomes of patients with primary mediastinal large B-cell lymphoma (PMLBCL) with sclerosis after first-generation (dose-intensive regimens), third-generation (alternating regimens) and high-dose chemotherapy strategies, frequently with adjuvant radiation therapy. DESIGN AND METHODS: Between August 1981 and December 1999, a total of 426 previously untreated patients with confirmed diagnosis were enrolled in 20 institutions to receive combination chemotherapy with either first generation (CHOP or CHOP-like) regimens, third generation (MACOP-B, VACOP-B, ProMACE CytaBOM) regimens or high-dose chemotherapy (HDS/ABMT). RESULTS: With chemotherapy, complete response (CR) rates were 49% (50/105), 51% (142/277) and 53% (23/44) with first generation, third generation and high-dose chemotherapy strategies, respectively; partial response (PR) rates were 32%, 36% and 35%, respectively. All patients who achieved CR and 124/142 (84%) with PR had radiation therapy on the mediastinum. The final CR rates became 61% for CHOP/CHOP-like regimens, 79% for MACOP-B and other regimens, and 75% for HDS/ABMT. After median follow-ups from attaining CR of 48.5 months for CHOP/CHOP-like regimens, 51.7 months for MACOP-B type regimens and 32.4 months for HDS/ABMT, relapses occurred in 15/64 (23%), 27/218 (12%) and 0/33 (0%) patients, respectively. Projected 10-year progression-free survival rates were 35%, 67% and 78%, respectively (p=0.0000). Projected 10-year overall survival rates were 44%, 71% and 77%, respectively (p=0.0000), after median follow-ups from diagnosis of 52.3 months, 54.9 months and 35.8 months, respectively. INTERPRETATION AND CONCLUSIONS: In patients with PMLBCL with sclerosis, MACOP-B plus radiation therapy may be a better strategy than other treatments; these retrospective data need to be confirmed by prospective studies. The encouraging survival results after high dose chemotherapy require confirmation in selected high-risk patients.