Search Results (7)

Background/Objective: During the last two decades, several cases presenting with circulating clonal B-cells with features consistent with possible marginal zone (MZ) derivation have been described under different terminologies. The present study aims to shed more light onto the main disease characteristics and determine prognostic factors for outcome in 98 consecutive cases with clonal B-cell lymphocytosis of marginal zone origin (CBL-MZ). Methods: This is a multicenter retrospective analysis including 98 consecutive CD5(−) CBL cases referred to our Departments between 1999 and 2017. These cases were selected based on the presence of circulating CD5(−) clonal B-cells, irrespectively of their absolute number, without B-symptoms, organomegaly, lymphadenopathy or cytopenias or any other features consistent with a known lymphoproliferative disorder. Clinical, morphologic, biochemical, immunophenotypic, histologic and molecular features of CBL-MZ cases were analyzed. Results: The median absolute lymphocyte counts (ALCs) and circulating CBLs were 6.7 × 10⁹/L and 3.447 × 10⁹/L, respectively. Paraproteinemia was found in 38%. Bone marrow (ΒΜ) was involved in all but one case. MYD-88L265P mutation was positive in 11%. Two subcategories of CBL-MZ were identified: One was characterized by lower ALC/CBL, paraproteinemia, CD38 expression, BM lymphoplasmacytic morphology and more frequent MYD-88L265P mutation. The second category displayed a leukemic picture, higher frequency of CD11c expression, hypogammaglobulinemia and elevated LDH. Treatment-free survival (TFS) was 91%, and median freedom from progression (FFP) was 95.6 months. For TFS, two factors proved significant using multivariate analysis: BM infiltration ≥ 50% and elevated LDH (RR 5.6 and 5.4, respectively). Evolution to splenic marginal zone lymphoma was a rare event (5%). A novel pattern of progression emerged, namely development of cytopenias due to extensive BM infiltration without any other disease localization. Conclusions: CBL-MZ is an indolent lymphoproliferative disorder with excellent outcome and low probability of progression. Based on our findings, CBL-MZ represents a heterogeneous entity where the vast majority of cases remain stable or develop increasing lymphocytosis. Clinically, our data also highlight that the extent of BM infiltration and elevated LDH levels appear to be the most notable predictors for introducing therapy. Full article

Flow cytometry is an essential diagnostic method in hematology, and one of its main applications is the assessment of the clonality of mature B cells. We present a case report of a patient referred for the investigation of absolute lymphocytosis. The flow cytometry study revealed an increased percentage of B cells, but it could not establish B-cell clonality, based on the study of surface light chains in combination with the pattern of expression of mature B-cell markers. The diagnosis of Persistent Polyclonal B-cell Lymphocytosis (PPBL) was considered in the differential diagnosis as the mature B cells were found to be immunophenotypically memory B cells. However, due to the markedly elevated count of B cells, molecular testing with Polymerase Chain Reaction (PCR) for B-cell clonality based on IGH (Immunoglobulin Heavy Chain) gene rearrangements was performed, and it revealed the presence of two clones of B cells. Approximately one year later, the same work-up was repeated in the patient’s bone marrow aspirate. By flow cytometry, a distinct clonal B-cell population was isolated, while the molecular testing with PCR for B cell clonality based on IGH heavy-chain gene rearrangements revealed the presence of three clones of B cells. In addition, evaluation of the sample with high-dimensional mass cytometry showed the presence of four major immunophenotypically abnormal B-cell subsets. Full article

T-cell non-Hodgkin lymphomas, which arise from post-thymic mature T cells, constitute approximately 10–15% of all non-Hodgkin lymphomas. Their leukemic presentations, referred to here as mature T-cell leukemias, are relatively uncommon and present significant diagnostic and therapeutic challenges requiring an informed approach to diagnosis and management. The initial presentation is often persistent T-cell lymphocytosis that must be distinguished from reactive (non-malignant) causes. Unlike B-cell lymphocytosis, where clonality usually indicates malignancy, T-cell clonality can be detected in benign conditions such as autoimmune disorders and viral infections. Thus, establishing clonality is helpful but not sufficient, and a systematic diagnostic approach integrating clinical features, morphology, immunophenotype, and molecular findings is critical. This review outlines our approach to the diagnosis and treatment of four major subtypes of mature T-cell leukemias: T-cell prolymphocytic leukemia (T-PLL), adult T-cell leukemia/lymphoma (ATLL), T-large granular lymphocytic leukemia (T-LGL), and Sézary syndrome (SS). Each section includes a discussion of clinical features, workup, and treatment options. Full article

Background: The Sysmex XN series (XN-1000 and XN-9100, Sysmex Corporation, Kobe, Japan) represents a latest-generation automated hematology platform integrating fluorescence-based technologies and multi-channel analysis (WDF and WPC) to improve leukocyte characterization. This study aimed to evaluate the performance of the Sysmex XN series in detecting leukocyte abnormalities flagged during routine complete blood count analysis in a large cohort of healthy donors, using morphological assessment and flow cytometry as confirmatory methods. Methods: Approximately 8000 healthy blood donors from the AOU Meyer Transfusion Centre were evaluated between 2021 and 2024. All samples underwent CBC analysis using the XN-1000 and XN-9100 analyzers with the WDF channel. Samples showing WBC-related flags were subjected to reflex testing with the WPC channel, followed by digital blood smear review using the DI-60 system (CellaVision, Lund, Sweden) and flow cytometric immunophenotyping. Results: WDF flags for “blasts/abnormal lymphocytes” were identified in 23 samples. Two samples were negative on WPC analysis as well as on morphological and flow cytometric evaluation. Among the remaining cases, WPC analysis identified flags for abnormal lymphocytes, atypical lymphocytes, or blasts, which were variably associated with reactive changes, transient immune activation, or clonal lymphoproliferative conditions. In one donor, monoclonal B-cell lymphocytosis was diagnosed by flow cytometry. Overall, reactive morphological features confirmed by flow cytometry were observed in approximately 50% of flagged cases. Conclusions: WPC analysis provides relevant additional diagnostic information and demonstrates higher specificity compared with the WDF channel alone; however, it does not fully resolve all instrument-generated flags, confirming the essential role of morphological assessment. Interestingly, the frequent occurrence of inflammatory profiles in recently vaccinated donors suggests that transient immune activation may influence leukocyte flagging. Larger studies are warranted to further investigate this association and to optimize the diagnostic performance of the WPC channel in donor screening. Full article

Bovine leukemia virus (BLV) is a retrovirus infecting several bovid species, notably Bos taurus, where it fulfills Koch’s postulates for pathogenicity. The virus primarily targets B-lymphocytes, establishing lifelong infections that remain mostly asymptomatic but can progress to lymphocytosis or lymphoma. Transmission occurs through live infected cells via blood, milk, or transplacental routes. Despite a robust antiviral immunity, BLV replicates by producing virions (i.e., the infectious cycle) or inducing mitosis of infected cells (i.e., clonal expansion). The immune system effectively controls the infectious cycle but fails to impede clonal expansion, leading to chronic immune activation and immunosuppression. BLV modifies the transcriptome of the host cell by expressing oncogenic factors (Tax), viral microRNAs and antisense RNAs. Leukemogenesis arises from cumulative alterations of the virus (e.g., 5′-end deletions of the integrated provirus and histone modifications of the LTR promoter) and the host cell (e.g., genomic mutations and favorable chromatin integration). This model underscores a unique persistence strategy, linking chronic infection, immune evasion, and slow multistep oncogenesis in the bovine host. Full article

A 2-year-old neutered female Small Munsterlander dog was presented for an insect bite. Physical examination revealed a poor body condition, a peripheral lymphadenomegaly, and suspected splenomegaly. A complete blood count (Sysmex XN-V) revealed marked leukocytosis with lymphocytosis and abnormal dot plots. An abnormal monomorphic lymphoid population and marked rouleaux formation were noted on the blood smear. Lymph node aspirates contained an atypical bimorphic population of lymphocytes, either with a plasmacytoid or a blastic appearance. This double population was also found in the spleen, liver, bone marrow, tonsils, and other tissues. Peripheral blood and lymph node clonality assays revealed clonal BCR gene rearrangement. Flow cytometry revealed a mixed population of small-sized B-cells (CD79a+ CD21+ MHCII+) and medium-sized B-cells (CD79a+ CD21− MHCII−) in lymph nodes and a dominant population of small-sized mature B-cells (CD21+ MHCII+) in peripheral blood. Though normoproteinemic, serum protein electrophoresis revealed an increased α2-globulin fraction with an atypical restricted peak, identified as monoclonal IgM by immunofixation. Urine protein immunofixation revealed a Bence-Jones proteinuria. A diagnosis of Waldenström’s macroglobulinemia was made. Chemotherapy was initiated, but the dog was euthanized 12 months after the initial presentation due to marked clinical degradation. Full article

STAT3 and STAT5B (STAT3/STAT5B) mutations are the most common mutations in T-cell large granular lymphocytic leukemia (T-LGLL) and chronic lymphoproliferative disorders of NK cells (CLPD-NK), but their clinical impact remains unknown. We investigated the frequency and type of STAT3/STAT5B mutations in FACS-sorted populations of expanded T/NK-LGL from 100 (82 clonal; 6 oligoclonal; 12 polyclonal) patients, and its relationship with disease features. Seventeen non-LGL T-CLPD patients and 628 age-matched healthy donors were analyzed as controls. STAT3 (n = 30) and STAT5B (n = 1) mutations were detected in 28/82 clonal T/NK-LGLL patients (34%), while absent (0/18, 0%) among oligoclonal/polyclonal LGL-lymphocytosis. Mutations were found across all diagnostic subgroups: TCD8⁺-LGLL, 36%; CLPD-NK, 38%; TCD4⁺-LGLL, 7%; Tαβ⁺DP-LGLL, 100%; Tαβ⁺DN-LGLL, 50%; Tγδ⁺-LGLL, 44%. STAT3-mutated T-LGLL/CLPD-NK showed overall reduced (p < 0.05) blood counts of most normal leukocyte subsets, with a higher rate (vs. nonmutated LGLL) of neutropenia (p = 0.04), severe neutropenia (p = 0.02), and cases requiring treatment (p = 0.0001), together with a shorter time-to-therapy (p = 0.0001), particularly in non-Y640F STAT3-mutated patients. These findings confirm and extend on previous observations about the high prevalence of STAT3 mutations across different subtypes of LGLL, and its association with a more marked decrease of all major blood-cell subsets and a shortened time-to-therapy. Full article