Search

Abstract: Introduction: Flow cytometry is a useful tool for diagnosis and minimal residual disease (MRD) study of hematological diseases. Standard sample preparation protocols are characterized by stain‐lyse‐wash (SLW). To prevent nonspecific bindings and achieve high sensitivity in MRD studies, lyse‐wash‐stain‐wash (LWSW) is required. To our knowledge, no comparison between the two methods has been performed. Methods: We compared mean fluorescence intensity (MFI), stain index, signal‐to‐noise ratio, and percentage of positive cells of 104 antibodies and of 13 selected antibodies tested in 10 samples simultaneously prepared with the two methods. Results: MFI and percentages of positive cells obtained by the two methods did not show significant differences and showed a very high correlation. Stain index and signal‐to‐noise ratio presented higher values for kappa and lambda surface chains in LWSW samples and a trend of higher values for the other antibodies in SLW samples. Conclusions: We suggest to use LWSW method also at diagnosis to obtain more comparable antibody intensity expressions when samples from the same patient are processed for MRD evaluation after bulk lysis. Moreover, LWSW can prevent nonspecific bindings, shows no differences in the identification and quantitation of the populations of interest, and reduces acquisition of cell debris. [ABSTRACT FROM AUTHOR]

The diagnosis of Waldenström's macroglobulinemia (WM), an IgM-associated lymphoplasmacytic lymphoma, can be challenging due to the different forms of disease presentation. Furthermore, in recent years, WM has witnessed remarkable progress on the diagnostic front, as well as a deeper understanding of the disease biology, which has affected clinical practice. This, together with the increasing variety of tools and techniques available, makes it necessary to have a practical guidance for clinicians to perform the initial evaluation of patients with WM. In this paper, we present the consensus recommendations and laboratory requirements for the diagnosis of WM developed by the European Consortium of Waldenström's Macroglobulinemia (ECWM), for both clinical practice as well as the research/academical setting. We provide the procedures for multiparametric flow cytometry, fluorescence in situ hybridization and molecular tests, and with this offer guidance for a standardized diagnostic work-up and methodological workflow of patients with IgM monoclonal gammopathy of uncertain significance, asymptomatic and symptomatic WM., (© 2022. The Author(s).)

Purpose: High levels of circulating tumor plasma cells (CTC-high) in patients with multiple myeloma are a marker of aggressive disease. We aimed to confirm the prognostic impact and identify a possible cutoff value of CTC-high for the prediction of progression-free survival (PFS) and overall survival (OS), in the context of concomitant risk features and minimal residual disease (MRD) achievement., Methods: CTC were analyzed at diagnosis with two-tube single-platform flow cytometry (sensitivity 4 × 10 -5 ) in patients enrolled in the multicenter randomized FORTE clinical trial (ClinicalTrials.gov identifier: NCT02203643). MRD was assessed by second-generation multiparameter flow cytometry (sensitivity 10 -5 ). We tested different cutoff values in series of multivariate (MV) Cox proportional hazards regression analyses on PFS outcome and selected the value that maximized the Harrell's C-statistic. We analyzed the impact of CTC on PFS and OS in a MV analysis including baseline features and MRD negativity., Results: CTC analysis was performed in 401 patients; the median follow-up was 50 months (interquartile range, 45-54 months). There was a modest correlation between the percentage of CTC and bone marrow plasma cells ( r = 0.38). We identified an optimal CTC cutoff of 0.07% (approximately 5 cells/µL, C-index 0.64). In MV analysis, CTC-high versus CTC-low patients had significantly shorter PFS (hazard ratio, 2.61; 95% CI, 1.49 to 2.97, P < .001; 4-year PFS 38% v 69%) and OS (hazard ratio, 2.61; 95% CI, 1.49 to 4.56; P < .001; 4-year OS 68% v 92%). The CTC levels, but not the bone marrow plasma cell levels, affected the outcome. The only factor that reduced the negative impact of CTC-high was the achievement of MRD negativity (interaction P = .039)., Conclusion: In multiple myeloma, increasing levels of CTC above an optimal cutoff represent an easy-to-assess, robust, and independent high-risk factor. The achievement of MRD negativity is the most important factor that modulates their negative prognostic impact.

Minimal residual disease (MRD) by multiparameter flow cytometry (MFC) is the most effective tool to define a deep response in multiple myeloma (MM). We conducted an MRD correlative study of the EMN02/HO95 MM phase III trial in newly diagnosed MM patients achieving a suspected complete response before maintenance and every 6 months during maintenance. Patients received high-dose melphalan (HDM) versus bortezomib-melphalan-prednisone (VMP) intensification, followed by bortezomib-lenalidomide-dexamethasone (VRd) versus no consolidation, and lenalidomide maintenance. Bone marrow (BM) samples were processed in three European laboratories, applying EuroFlow-based MFC protocols (eight colors, two tubes) with 10 -4 -10 -5 sensitivity. At enrollment in the MRD correlative study, 76% (244/321) of patients were MRD-negative. In the intention-to-treat analysis, after a median follow-up of 75 months, 5-year progression-free survival was 66% in MRD-negative versus 31% in MRD-positive patients (HR 0.39; p < 0.001), 5-year overall survival was 86% versus 69%, respectively (HR 0.41; p < 0.001). MRD negativity was associated with reduced risk of progression or death in all subgroups, including ISS-III (HR 0.37) and high-risk fluorescence in situ hybridization (FISH) patients (HR 0.38;). In the 1-year maintenance MRD population, 42% of MRD-positive patients at pre-maintenance became MRD-negative after lenalidomide exposure. In conclusion, MRD by MFC is a strong prognostic factor. Lenalidomide maintenance further improved MRD-negativity rate.

Despite remarkable advances in the treatment of multiple myeloma in the last decades, the prognosis of patients harboring high-risk cytogenetic abnormalities remains dismal as compared to that of standard-risk patients. Proteasome inhibitors demonstrated to partially ameliorate the prognosis of high-risk patients. We pooled together data from two phase I/II trials on transplant-ineligible patients with multiple myeloma receiving upfront carfilzomib cyclophosphamide and dexamethasone followed by carfilzomib maintenance. The aim of this analysis was to compare treatment outcomes in patients with standard- versus high-risk cytogenetic abnormalities detected by fluorescence in situ hybridization (FISH) analysis. High risk was defined by the presence of at least one chromosomal abnormality, including t(4;14), del17p and t(14;16). Overall, 94 patients were included in the analysis: 57 (61%) in the standard-risk and 37 (39%) in the high-risk group. Median follow-up was 38 months. In standard- vs. high-risk patients, we observed similar progression-free survival (3-year PFS: 52% vs. 43%, respectively; p=0.50), overall survival (3-year OS: 78% vs. 73%; p=0.38), and overall response rate (88% vs 95%; p=0.47), with no statistical differences between the two groups. No difference in terms of progression-free survival was observed between patients with or without del17p. Carfilzomib, used both as induction and maintenance agent for transplant-ineligible newly diagnosed multiple myeloma patients, mitigated the poor prognosis carried by high-risk cytogenetics and resulted into similar progression-free survival and overall survival, as compared to standard-risk patients. ClinicalTrials.gov IDs: NCT01857115 (IST-CAR-561) and NCT01346787 (IST-CAR-506).

We analyzed variations in terms of chromosomal abnormalities (CA) by fluorescence in situ hybridization (FISH) analysis on purified bone marrow plasma cells throughout the progression from monoclonal gammopathy of undetermined significance/smoldering multiple myeloma (MGUS/SMM) to newly diagnosed MM/plasma cell leukemia (NDMM/PCL) at diagnosis and from diagnostic samples to progressive disease. High risk was defined by the presence of at least del(17p), t(4;14), and/or t(14;16). 1p/1q detection (in the standard FISH panel from 2012 onward) was not available for all patients. We analyzed 139 MM/PCL diagnostic samples from 144 patients, with a median follow-up of 71 months: high-risk CA at diagnosis (MGUS/SMM or NDMM) was present in 28% of samples, whereas 37-39% showed high-risk CA at relapse. In 115 patients with NDMM who evolved to relapsed/refractory MM, we identified 3 different populations: (1) 31/115 patients (27%) with gain of new CA (del13, del17p, t(4;14), t(14;16) or 1q CA when available); (2) 10/115 (9%) patients with loss of a previously identified CA; and (3) 74 patients with no changes. The CA gain group showed a median overall survival of 66 months vs. 84 months in the third group (HR 0.56, 95% CI 0.34-0.92, p = 0.023). Clonal evolution occurs as disease progresses after different chemotherapy lines. Patients who acquired high-risk CA had the poorest prognosis. Our findings highlight the importance of performing FISH analysis both at diagnosis and at relapse.

Background: Minimal residual disease (MRD) is one of the most relevant prognostic factors in patients with multiple myeloma (MM); however, the impact of maintenance therapy on MRD levels remains unclear. Among patients with newly diagnosed MM (NDMM) who received lenalidomide maintenance until they developed disease progression, the role of MRD status as a predictor of progression-free survival (PFS) was evaluated by multiparameter flow cytometry (MFC) and allelic-specific oligonucleotide real-time quantitative polymerase chain reaction (ASO-RQ-PCR) analysis., Methods: Seventy-three patients with NDMM enrolled in the RV-MM-EMN-441 (clinical trials.gov identifier, NCT01091831) and RV-MM-COOP-0556 (clinicaltrials.gov identifier, NCT01208766; European Myeloma Network EMN02/HO95 MM Trial) phase 3 trials who achieved at least a very good partial response after intensification/consolidation were included. The median patient age was 57 years (interquartile range, 53-61 years), and all patients received lenalidomide maintenance until they developed progression. MRD was evaluated on bone marrow after intensification/consolidation, after 6 courses of maintenance, and every 6 months thereafter until clinical relapse using both ASO-RQ-PCR (sensitivity, 10 -5 ) and MFC (sensitivity, from 10 -4 to 10 -5 )., Results: After intensification/consolidation, 33 of 72 patients (46%) achieved a molecular complete response (m-CR), and 44 of 70 (63%) achieved a flow complete response (flow-CR). Almost 27% of patients who were MRD-positive after consolidation became MRD-negative during maintenance. After a median follow-up of 38 months, PFS was prolonged in patients who achieved negative MRD status during maintenance according to results from both ASO-RQ-PCR analysis (hazard ratio, 0.29; 95% confidence interval, 0.14-0.62; P = .0013) and MFC (hazard ratio, 0.19; 95% confidence interval, 0.09-0.41; P < .001). The impact of negative MRD status on PFS was similar in all subgroups (ASCT and no-ASCT; International Staging System stages I, II, and III; high-risk and standard-risk cytogenetics), and the two techniques were highly correlated., Conclusions: MRD status is a stronger predictor of PFS than standard risk factors, and lenalidomide maintenance further increases the rate of negative MRD results., (© 2018 American Cancer Society.)

Background: Risk-adapted therapy is a common strategy in curable hematologic malignancies: standard-risk patients receive less intensive treatment, whereas high-risk patients require a more intensive approach. This model cannot be applied in multiple myeloma (MM), which is still incurable. Continuous treatment (CT) is a key strategy for MM treatment, since it improves duration of remission. However, the role of CT according to standard- or high-risk baseline prognosis remains an open question., Patients and Methods: We performed a pooled analysis of 2 phase III trials (GIMEMA-MM-03-05 and RV-MM-PI-209) that randomized patients to CT vs fixed-duration therapy (FDT)., Results: In the overall patient population (n = 550), CT improved progression-free survival1 (PFS1) (HR 0.54), PFS2 (HR 0.61) and overall survival (OS) (HR 0.71) vs FDT. CT improved PFS1 both in R-ISS I (HR 0.49) and R-ISS II/III patients (HR 0.55). Four-year PFS1 was 38% in R-ISS II/III patients receiving CT and 25% in R-ISS I patients receiving FDT, with similar trends for PFS2 and OS. High-risk patients benefited more from proteasome-inhibitor plus immunomodulatory-based CT than immunomodulatory alone., Conclusion: Good prognosis patients receiving FDT lose their prognostic advantage over high-risk patients receiving CT and high-risk patients may benefit from more intensive maintenance including proteasome inhibitors and immunomodulators., (Copyright © 2018 Elsevier B.V. All rights reserved.)

CD200, a transmembrane type Ia glycoprotein belonging to the immunoglobulin superfamily, has been shown to have a differential expression in B-cell neoplasms. Here, we retrospectively assessed the diagnostic relevance of CD200 on 427 patients with B-cell chronic neoplasms in leukemic phase (median age, 69 y; range, 35-97 y). The final diagnosis based on the investigator's assessment was chronic lymphocytic leukaemia (CLL) in 75% of cases and non-CLL in 25% of cases. Sensitivity and specificity for the diagnosis of CLL (vs non-CLL) were calculated for the following markers: CD200, CD5, CD22, CD23, CD79b, FMC7, and SmIg. CD23 was the only marker without a statistically significant difference between the investigator assessment and the flowcytometric analysis. The other markers were unable-when individually evaluated-to discriminate between CLL and non-CLL, requiring the integration into a scoring system. The modified score no. 1 (addition of CD200) showed superimposable sensitivity and specificity compared with the Matutes score. The substitution of CD79b (modified score no. 2), surface membrane immunoglobulins (SmIg) (modified score no. 3), and CD79b and FMC7 (modified score no. 4) with CD200 showed that only the modified score no. 4 had both higher sensitivity and higher specificity compared with standard Matutes score. In conclusion, this work defines a simplified score, compared with the classical Matutes score, for the differential diagnosis of chronic B-cell leukaemia-which only requires 4 markers instead of 5 (CD5, CD23, CD200, and SmIg)., (Copyright © 2018 John Wiley & Sons, Ltd.)

We analyzed 50 patients who achieved at least a very good partial response in the RV-MM-EMN-441 study. Patients received consolidation with autologous stem-cell transplantation (ASCT) or cyclophosphamide-lenalidomide-dexamethasone (CRD), followed by Lenalidomide-based maintenance. We assessed minimal residual disease (MRD) by multi-parameter flow cytometry (MFC) and allelic-specific oligonucleotide real-time quantitative polymerase chain reaction (ASO-RQ-PCR) after consolidation, after 3 and 6 courses of maintenance, and thereafter every 6 months until progression. By MFC analysis, 19/50 patients achieved complete response (CR) after consolidation, and 7 additional patients during maintenance. A molecular marker was identified in 25/50 patients, 4/25 achieved molecular-CR after consolidation, and 3 additional patients during maintenance. A lower MRD value by MFC was found in ASCT patients compared with CRD patients (p=0.0134). Tumor burden reduction was different in patients with high-risk vs standard-risk cytogenetics (3.4 vs 5.2, ln-MFC; 3 vs 6 ln-PCR, respectively) and in patients who relapsed vs those who did not (4 vs 5, ln-MFC; 4.4 vs 7.8 ln-PCR). MRD progression anticipated clinical relapse by a median of 9 months while biochemical relapse by a median of 4 months. MRD allows the identification of a low-risk group, independently of response, and a better characterization of the activity of treatments.

Background: Multiple Myeloma (MM) is a neoplastic disorder characterized by clonal proliferation of malignant plasma cells (PCs). Flow cytometry is an essential tool to confirm diagnosis and evaluate minimal residual disease (MRD). This study aims at identifying new surface PC markers suitable for targeted therapy in MM and able to improve MRD detection., Methods: The expression of 82 molecules provided by the "Ninth International Workshop on Leukocyte Antigens" was analyzed by flow cytometry in 5 MM cell lines and in 20 newly diagnosed MM (NDMM) patients. Based on the antigens expression and monoclonal antibody availability, CD150, CD48, CD229, CD352, CD319, CD272, CD86, CD200 and CD184 were subsequently tested in 24 NDMM, 8 relapsed MM (RMM), 6 plasma cell leukemia (PCL) and 13 healthy subjects., Results: CD352 was less frequently expressed on NDMM than on healthy PCs; CD200 was more frequently expressed on NDMM than on RMM and healthy PCs. CD150, CD319, CD229, CD352 Mean Fluorescence Intensity (MFI) was lower in pathological than in healthy samples. The proportion of CD150-positive samples was lower in NDMM and RMM than in healthy subjects; CD86+ samples were less frequent in NDMM than in healthy subjects; CD200+ samples were more frequent in NDMM than in RMM and healthy subjects., Conclusions: CD150, CD86 and CD200 can help to identify malignant PCs; CD272, CD319, CD229, CD48 are highly expressed on all PCs and could be considered for targeted therapy. All these antigens could be added to a routine panel for PCs identification and MRD evaluation., (© 2015 International Clinical Cytometry Society.)

Studies of gene expression profiling have been successfully used for the identification of molecules to be employed as potential prognosticators. In analogy with gene expression profiling, we have previously proposed an original method to identify the immunophenotypic signature of chronic lymphocytic leukemia (CLL) subsets with different prognosis, named surface-antigen expression profiling. According to this method, expression data for surface markers can be successfully analyzed by data mining tools identical to those employed in gene expression profiling studies, including unsupervised and supervised algorithms, with the aim to identify the immunophenotypic signature of CLL subsets with different prognosis. By employing an identical approach for investigating the reactivity of a wide panel of monoclonal antibodies provided by the "Ninth International Workshop on Leukocyte Differentiation Antigens", we were able to identify some of them (i.e. TCL1, CCR7, FCRL2, FCRL3, and CD150) as additional potential markers with prognostic relevance in CLL. These suggestions need to be confirmed: (i) in a new set of clinically characterized CLL cases; (ii) in combination with other prognostic markers in the context of comprehensive scoring systems for clinical outcome prediction., (Copyright © 2010 Elsevier B.V. All rights reserved.)