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Morphological and immunohistochemical (IHC) analysis of bone marrow biopsies (BMB) is routinely performed during staging of patients with non-Hodgkin's lymphoma (NHL). Aiming to evaluate the possible diagnostic value of flow cytometry (FC) on bone marrow aspirates (BMA), as compared with BMB, we retrospectively reviewed BMA specimen of 354 NHL. In 305 cases (86.1 %), there was a concordance between the two investigations. A discordance was detected in 49 cases (14 %): in 33 of these (9.3 % of total population), FC analysis of BMA was positive, whereas BMB, supported by IHC, was negative; in 16 (4.5 % of total population), FC did not detected lymphoid infiltration, while BMB was positive. Although the clinical implications of such an observation remain unclear, we think our results may be useful in the context of current staging procedures, also opening a possible future perspective in the setting of minimal measurable disease in these patients., (Copyright © 2019. Published by Elsevier Ltd.)

In this study, we aimed at disclosing the main features of paroxysmal nocturnal hemoglobinuria (PNH) clones, their association with presentation syndromes, and their changes during follow-up. A large-scale, cooperative collection (583 clones from 529 patients) of flow cytometric and clinical data was entered into a national repository. Reason for testing guidelines were provided to the 41 participating laboratories, which followed the 2010 technical recommendations for PNH testing by Borowitz. Subsequently, the 30 second-level laboratories adopted the 2012 guidelines for high-resolution PNH testing, both upon order by the local clinicians and as an independent laboratory initiative in selected cases. Type3 and Type2 PNH clones (total and partial absence of glycosyl-phosphatidyl-inositol-anchor, respectively) were simultaneously present in 54 patients. In these patients, Type3 component was sevenfold larger than Type2 (p < 0.001). Frequency distribution analysis of solitary Type3 clone size (N = 442) evidenced two discrete patterns: small (20% of peripheral neutrophils) and large (> 70%) clones. The first pattern was significantly associated with bone marrow failure and myelodysplastic syndromes, the second one with hemolysis, hemoglobinuria, and thrombosis. Pediatric patients (N = 34) showed significant preponderance of small clones and bone marrow failure. The majority of PNH clones involved neutrophils, monocytes, and erythrocytes. Nevertheless, we found clones made exclusively by white cells (N = 13) or erythrocytes (N = 3). Rare cases showed clonal white cells restricted only to monocytes (6 cases) or neutrophils (3 cases). Retesting over 1-year follow-up in 151 cases showed a marked clone size increase in 4 cases and a decrease in 13, demonstrating that early breaking-down of PNH clones is not a rare event (8.6% of cases). This collaborative nationwide study demonstrates a clear-cut difference in size between Type2 and Type3 clones, emphasizes the existence of just two classes of PNH presentations based on Type3 clone size, depicts an asymmetric cellular composition of PNH clones, and documents the possible occurrence of changes in clone size during the follow-up.

Lymphoproliferative diseases are a heterogeneous set of malignant clonal proliferations of lymphocytes. Despite well-established diagnostic criteria, the diagnosis remains difficult due to their variety in clinical presentation and immunophenotypic profile. Lymphoid T-cell disorders are less common than B-cell entities, and the lack of a clear immunophenotypic characteristic makes their identification hard. Flow cytometry turned out to be a useful tool in diagnosing T-cell disorders and to resolve complicated cases, especially if the number of analyzable neoplastic cells is small. We present a case of a 55-year-old man with simultaneous lymphoproliferative neoplastic T-cell clones, one αβ and the other γδ, identified and characterized by flow cytometry (FC), exploiting the variable expression intensity of specific markers. However, the patient's rapid decline made it impossible to define a differential diagnosis in order to confirm the identity of the γδ clone, which remains uncertain. This case is added to the few other cases already documented in the literature, characterized by the co-existence of T-large granular lymphocytic leukemia (T-LGLL)-αβ and T-LGLL-γδ/Hepatosplenic T-cell lymphoma (HSTCL). Our case underlines the key role of sensitive diagnostic tools in the assessment of potential relationship between the diagnosis, prognosis, and treatment in the two pathologies. [ABSTRACT FROM AUTHOR]

Simple Summary: Chronic lymphocytic leukemia (CLL) may be atypical in terms of the cell morphology picture, but also with regard to the surface immunophenotypic profile. Aiming at assessing the impact of morphology and immunophenotype in defining the atypical characteristics of CLL in terms of clinical–biological features and prognosis, a retrospective analysis of a large cohort of CLL patients was performed. We found that morphology better predicts the prognosis of atypical CLL compared to immunophenotypic analysis. Also, discordant cases in terms of immunophenotype and morphology did not identify specific prognostic groups. Overall, the question that still needs to be answered is: does it make sense to focus on morphology and immunophenotypic features in CLL in the era of molecular markers used as prognostic indicators? Atypical chronic lymphocytic leukemia (CLL) is still defined according to morphological criteria. However, deviance from the typical surface immunological profile suggests an atypical immunological-based CLL. A large cohort of patients with CLL was retrospectively evaluated aiming at assessing morphological (FAB criteria), immunophenotypical (two or more discordances from the typical profile), and clinical–biological features of atypical CLL. Compared to typical cases, morphologically atypical CLL showed a greater percentage of unmutated IgVH and CD38 positivity, and a higher expression of CD20. Immunophenotypically atypical CLL was characterized by more advanced clinical stages, higher expression of CD20, higher rate of FMC7, CD79b and CD49d positivity, and by an intermediate–high expression of membrane surface immunoglobulin, compared to typical cases. When patients were categorized based on immunophenotypic and morphologic concordance or discordance, no difference emerged. Finally, morphological features better discriminated patients' prognosis in terms of time-to-first treatment, while concordant atypical cases showed overall a worse prognosis. Discordant cases by immunophenotype and/or morphology did not identify specific prognostic groups. Whether—in the era of molecular markers used as prognostic indicators—it does make sense to focus on morphology and immunophenotype features in CLL is still matter of debate needing further research. [ABSTRACT FROM AUTHOR]

Background: B‐cell chronic lymphocytic leukemia (B‐CLL) is characterized by the expansion of CD5+ malignant B lymphocytes. Recent discoveries have shown that double‐negative T (DNT) cells, double‐positive T (DPT) cells, and natural killer T (NKT)‐cells may be involved in tumor surveillance. Methods: A detailed immunophenotypic analysis of the peripheral blood T‐cell compartment of 50 patients with B‐CLL (classified in three prognostic groups) and 38 healthy donors (as controls) matched for age was performed. The samples were analyzed by flow cytometry using a stain‐lyse‐no wash technique and a comprehensive six‐color antibody panels. Results: Our data confirmed a reduction in percentage values and an increase in absolute values of T lymphocytes in patients with B‐CLL, as already reported. In particular, DNT, DPT, and NKT‐like percentages were significantly lower than in the controls, except for NKT‐like in the low‐risk prognostic group. Moreover, a significant rise in the absolute counts of DNT cells in each prognostic group and in the low‐risk prognostic group of NKT‐like cells was found. A significant correlation of the absolute values of NKT‐like cells in the intermediate‐risk prognostic group versus B cells was observed. Furthermore, we analyzed whether the increase in T cells was related to the subpopulations of interest. Only DNT cells were positively correlated with the increase in CD3+ T lymphocytes, regardless of the stage of the disease, supporting the hypothesis that this T‐cell subset plays a key role in the immune T response in B‐CLL. Conclusion: These early results supported that DNT, DPT, and NKT‐like subsets may be related to disease progression and should encourage further studies aimed at identifying the potential immune surveillance role of these minority T subpopulations. [ABSTRACT FROM AUTHOR]

A case of concomitant hairy cell leukemia (HCL) and chronic lymphocytic leukemia (CLL) in a 50- year-old man was reported. Flow cytometry and droplet digital PCR (ddPCR) were used to detect the B-Raf proto-oncogene (BRAF) V600E mutation. The HCL population was the predominant component. The patient was first treated with cladribine and then with rituximab and achieved HCL partial remission. Importantly, the high sensitivity of our flow cytometric approach allowed the detection of a small population “P3,” in addition to the typical HCL and CLL clones. The P3 clone changed over time, from an HCL-like to a CLL-like immunophenotype. This case is added to the few other cases of synchronous HCL and CLL already reported in the literature and underlines the importance of analyzing chronic lymphoproliferative disorders by highly sensitive diagnostic techniques, like the multicolor flow cytometry and ddPCR, to evaluate the possible association between HCL and CLL at diagnosis. [ABSTRACT FROM AUTHOR]

Measurable residual disease (MRD) has emerged as a relevant parameter of response to therapy in chronic lymphocytic leukemia (CLL). Although several methods have been developed, flow cytometry has emerged as the most useful and standardized approach to measure and quantify MRD. The improved sensitivity of MRD measurements has been paralleled by the development of more effective therapeutic strategies for CLL, increasing the applicability of MRD detection in this setting. Chemotherapy and chemoimmunotherapy have firstly demonstrated their ability to obtain a deep MRD. Combined targeted therapies are also demonstrating a high molecular response rate and prospective trials are exploring the role of MRD to guide the duration of treatment in this setting. In this review we briefly summarize what we have learned about MRD with emphasis on its flow cytometric detection. [ABSTRACT FROM AUTHOR]

CD200, a transmembrane type Ia glycoprotein belonging to the immunoglobulin protein superfamily, is broadly expressed on a wide variety of cell types, such as B lymphocytes, a subset of T lymphocytes, dendritic cells, endothelial and neuronal cells. It delivers immunosuppressive signals through its receptor CD200R, which is expressed on monocytes/myeloid cells and T lymphocytes. Moreover, interaction of CD200 with CD200R has also been reported to play a role in the regulation of tumor immunity. Overexpression of CD200 has been reported in chronic lymphocytic leukemia (CLL) and hairy cell leukemia but not in mantle cell lymphoma, thus helping to better discriminate between these different B cell malignancies with different prognosis. In this review, we focus on the role of CD200 expression in the differential diagnosis of mature B-cell neoplasms and on the prognostic significance of CD200 expression in CLL, where conflicting results have been published so far. Of interest, increasing evidences indicate that anti-CD200 treatment might be therapeutically beneficial for treating CD200-expressing malignancies, such as CLL. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The article discusses a study which examines the impact of lenalidomide, an immunomodulatory agent, on the CD20 antigen surface expression on chronic lymphocytic leukemia (CLL) B-cells using a flow cytometry (FC) analysis. Findings reveal the heterogeneous modulating effects of lenalidomide on CD20 expression in CLL B-cells. The outcomes' agreement with other studies are also mentioned.