Predictive role of minimal residual disease and log clearance in acute myeloid leukemia: a comparison between multiparameter flow cytometry and Wilm's tumor 1 levels.

In acute myeloid leukemia (AML), the detection of minimal residual disease (MRD) as well as the degree of log clearance similarly identifies patients with poor prognosis. No comparison was provided between the two approaches in order to identify the best one to monitor follow-up patients. In this study, MRD and clearance were assessed by both multiparameter flow cytometry (MFC) and WT1 expression at different time points on 45 AML patients achieving complete remission. Our results by WT1 expression showed that log clearance lower than 1.96 after induction predicted the recurrence better than MRD higher than 77.0 copies WT1/10(4) ABL. Conversely, on MFC, MRD higher than 0.2 % after consolidation was more predictive than log clearance below 2.64. At univariate and multivariate analysis, positive MRD values and log clearance below the optimal cutoffs were associated with a shorter disease-free survival (DFS). At the univariate analysis, positive MRD values were also associated with overall survival (OS). Therefore, post-induction log clearance by WT1 and post-consolidation MRD by MFC represented the most informative approaches to identify the relapse. At the optimal timing of assessment, positive MRD and log-clearance values lower than calculated thresholds similarly predicted an adverse prognosis in AML.

Leukemia-associated immunophenotypes subdivided in "categories of specificity" improve the sensitivity of minimal residual disease in predicting relapse in acute myeloid leukemia.

BACKGROUND: The assessment of minimal residual disease (MRD) by flow cytometry (FC) has a prognostic impact in acute myeloid leukemia (AML), despite the low sensitivity in predicting relapse. Nonetheless, the role of leukemic-associated immunophenotypes (LAIPs)-related specificity on the sensitivity of MRD has not been clarified yet. In this respect, we accomplished this study. METHODS: LAIP-frequencies of bone marrow samples from healthy donors and patients after treatment were quantified and subdivided in "categories of specificity" named as: "strong," "good," and "weak." At the following, the diagnostic performance of MRD was investigated in terms of sensitivity, specificity, predictive values, likelihood ratio (LR). RESULTS: "Strong" LAIPs were identified by CD7, CD2, CD4, and CD56 markers while "weak" LAIPs, independently of coexpressed markers, were mainly observed in CD33+ cells. MRD identified patients with significantly low DFS and OS but showed a low sensitivity in predicting relapse. Interestingly, majority of recurrences was noticed in patients with two LAIPs and lacking of "strong" LAIPs or only with one "good" LAIP. Thus, only patients showing one "strong" or two "good" LAIPs were considered suitable for MRD monitoring and selected to be further investigated. In this subset, positive MRD predicted a poor prognosis. Moreover, a higher sensitivity, negative predictive value (NPV) and LR- were observed after comparison with the previous series. CONCLUSIONS: These data highlight the relevant role of LAIP classification in "categories of specificity" in improving the sensitivity of MRD as assessed by FC.

Active caspase-3 detection to evaluate apoptosis induced by Verbena officinalis essential oil and citral in chronic lymphocytic leukaemia cells

Verbena officinalis L., Verbenaceae, commonly known as vervain, is a plant widely used in medicine. Despite of its widespread use in different traditional practices, the mechanisms of pharmacological actions of the plant and its volatile oil are still unclear. We evaluated the pro-apoptotic activity of V. officinalis essential oil and of its main component, citral, on lymphocytes collected from ten patients with chronic lymphocytic leukaemia (CLL), a disease in which a faulty apoptotic mechanism is still retained one of the primary pathogenic events, by adding to treated mononuclear cells, annexin-V, propidium iodide, and CD19. Apoptosis was also evaluated using anti-active-caspase-3 monoclonal antibody after permeabilization of the cells. Both V. officinalis essential oil and citral were found able to induce apoptosis in CLL cells and to activate caspase-3, which is considered the way by means they active apoptosis in B neoplastic cells. This data further support evidences that indicate natural compounds as possible lead structure to develop new therapeutic agents for CLL.