Dual T-cell constant β chain (TRBC)1 and TRBC2 staining for the identification of T-cell neoplasms by flow cytometry.

The diagnosis of leukemic T-cell malignancies is often challenging, due to overlapping features with reactive T-cells and limitations of currently available T-cell clonality assays. Recently developed therapeutic antibodies specific for the mutually exclusive T-cell receptor constant β chain (TRBC)1 and TRBC2 isoforms provide a unique opportunity to assess for TRBC-restriction as a surrogate of clonality in the flow cytometric analysis of T-cell neoplasms. To demonstrate the diagnostic utility of this approach, we studied 164 clinical specimens with (60) or without (104) T-cell neoplasia, in addition to 39 blood samples from healthy donors.

Superior detection rate of plasma cell FISH using FACS-FISH.

Objectives: Fluorescence in situ hybridization (FISH) for plasma cell neoplasms (PCNs) requires plasma cell (PC) identification or purification strategies to optimize results. We compared the efficacy of cytoplasmic immunoglobulin FISH (cIg-FISH) and fluorescence-activated cell sorting FISH (FACS-FISH) in a clinical laboratory setting.

Methods: The FISH analysis results of 14,855 samples from individuals with a suspected PCN subjected to cytogenetic evaluation between 2019 and 2022 with cIg-FISH (n = 6917) or FACS-FISH (n = 7938) testing were analyzed.

Establishing NK-Cell Receptor Restriction by Flow Cytometry and Detecting Potential NK-Cell Clones of Uncertain Significance.

Natural killer (NK) cells develop a complex inhibitory and/or activating NK-cell receptor system, including killer cell immunoglobulin-like receptors (KIRs or CD158) and CD94/NKG2 dimers, which are variably combined to generate the individual's NK-cell receptor repertoire. Establishing NK-cell receptor restriction by flow cytometric immunophenotyping is an important step in diagnosing NK-cell neoplasms, but reference interval (RI) data for interpreting these studies are lacking. Specimens from 145 donors and 63 patients with NK-cell neoplasms were used to identify discriminatory rules based on 95% and 99% nonparametric RIs for CD158a+, CD158b+, CD158e+, KIR-negative, and NKG2A+ NK-cell populations to establish NK-cell receptor restriction.

Abnormal CD13/HLA-DR Expression Pattern on Myeloblasts Predicts Development of Myeloid Neoplasia in Patients With Clonal Cytopenia of Undetermined Significance.

Objectives: Patients with clonal cytopenia of undetermined significance (CCUS) are at increased risk of developing myeloid neoplasia (MN). We evaluated whether a simple flow cytometry immunophenotyping (FCIP) assay could differentiate the risk of development of MN in patients with CCUS.

Methods: Bone marrow aspirates were assessed by FCIP panel in a cohort of 80 patients identified as having CCUS based on next-generation sequencing or cytogenetics from March 2015 to May 2020, with available samples.

Artificial Intelligence Enhances Diagnostic Flow Cytometry Workflow in the Detection of Minimal Residual Disease of Chronic Lymphocytic Leukemia.

Flow cytometric (FC) immunophenotyping is critical but time-consuming in diagnosing minimal residual disease (MRD). We evaluated whether human-in-the-loop artificial intelligence (AI) could improve the efficiency of clinical laboratories in detecting MRD in chronic lymphocytic leukemia (CLL). We developed deep neural networks (DNN) that were trained on a 10-color CLL MRD panel from treated CLL patients, including DNN trained on the full cohort of 202 patients (F-DNN) and DNN trained on 138 patients with low-event cases (MRD < 1000 events) (L-DNN).

Evaluation of multiple myeloma measurable residual disease by high sensitivity flow cytometry: An international harmonized approach for data analysis.

Background: Multiple myeloma (MM) measurable residual disease (MRD) evaluated by flow cytometry is a surrogate for progression-free and overall survival in clinical trials. However, analysis and reporting between centers lack uniformity. We designed and evaluated a consensus protocol for MM MRD analysis to reduce inter-laboratory variation in MM MRD reporting.

Flow Cytometric Evaluation of Surface and Cytoplasmic TRBC1 Expression in the Differential Diagnosis of Immature T-Cell Proliferations.

Objectives: Flow cytometric detection of T-cell clonality is challenging, particularly in differential diagnosis of immature T-cell proliferations. Studies have shown utility of TRBC1, in conjunction with other T-cell markers, as reliable means to identify T-cell clonality by flow cytometry. One limitation of surface TRBC1 (sTRBC1) evaluation is it cannot be detected in surface CD3 (sCD3)-negative T cells, such as normal or abnormal immature T-cell precursors.

CD2 and CD7 are sensitive flow cytometry screening markers for T-lineage acute leukemia(s): a study of 465 acute leukemia cases.

T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) is a rare acute leukemia that expresses cytoplasmic CD3 (cCD3) and frequently lacks surface CD3. Given that routine flow cytometric testing for cCD3 may not be feasible and cCD3 interpretation may be difficult, we investigate if surface CD2 and/or CD7 expression on blasts can be used by flow cytometry to screen for T-lineage acute leukemia. We retrospectively reviewed flow cytometric data from 233 acute leukemias (36 T-ALL/LBL, 8 mixed-phenotype acute leukemia T/myeloid, 80 acute myeloid leukemia, 97 B-ALL/LBL, 8 mixed-phenotype acute leukemia B/myeloid, and 4 acute undifferentiated leukemia cases).

Single-Antibody Evaluation of T-Cell Receptor β Constant Chain Monotypia by Flow Cytometry Facilitates the Diagnosis of T-Cell Large Granular Lymphocytic Leukemia.

Objectives: The diagnosis of T-cell large granular lymphocytic leukemia (T-LGLL) is challenging because of overlapping immunophenotypic features with reactive T cells and limitations of T-cell clonality assays. We studied whether adding an antibody against T-cell receptor β constant region 1 (TRBC1) to a comprehensive flow cytometry panel could facilitate the diagnosis of T-LGLL.

Methods: We added TRBC1 antibody to the standard T-cell and natural killer (NK) cell panel to assess T-cell clonality in 56 T-LGLLs and 34 reactive lymphocytoses.

Implications of detecting serum monoclonal protein by MASS-fix following stem cell transplantation in multiple myeloma.

Measurable residual disease (MRD) assessment by marrow-based next-generation flow cytometry (NGF) following autologous stem cell transplantation (ASCT) may lead to false-negative results due to patchy marrow involvement and extramedullary disease in patients with multiple myeloma. We assessed the value of simultaneous MRD evaluation with NGF and serum matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MASS-FIX). Of all 61 complete responders who were NGF-negative for MRD, around day-100 post ASCT, 59% were MASS-FIX-positive.

Cytoplasmic Expression of CD3ε Heterodimers by Flow Cytometry Rapidly Distinguishes Between Mature T-Cell and Natural Killer-Cell Neoplasms.

Objectives: Distinguishing between T-cell and natural killer (NK)-cell neoplasms could be difficult given their overlapping immunophenotype. In this study, we investigated whether a flow cytometry assay with cytoplasmic staining for CD3 could be used for this purpose.

Methods: Flow cytometry immunophenotyping was performed on 19 surface CD3 (sCD3)-negative mature T-cell neoplasms, 10 sCD3-positive mature T-cell neoplasms, 13 mature NK-cell neoplasms, and 19 normal controls.

Flow cytometric evaluation of TRBC1 expression in tissue specimens and body fluids is a novel and specific method for assessment of T-cell clonality and diagnosis of T-cell neoplasms.

Background: Flow cytometric detection of T-cell clonality is challenging. The current available methodology for T-cell receptor (TCR) Vβ repertoire evaluation is a complex assay and has limited sensitivity especially for detecting low levels of disease. Therefore, there is an unmet need for a reliable, simple, and rapid assay to identify T-cell clonality.

Prevalence and spectrum of T-cell lymphoproliferative disorders in patients with Hypereosinophilia: A reference laboratory experience.

Hypereosinophilia (HE) is defined as persistently elevated absolute eosinophil count (AEC) ≥ 1.5 × 10/L, which can be due to a variety of underlying causes. In this study, we investigated the prevalence and spectrum of T-cell lymphoproliferative disorders in 124 consecutive patients with HE by flow cytometric immunophenotyping.

Single Antibody Detection of T-Cell Receptor αβ Clonality by Flow Cytometry Rapidly Identifies Mature T-Cell Neoplasms and Monotypic Small CD8-Positive Subsets of Uncertain Significance.

Background: The diagnosis of T-cell neoplasms is often challenging, due to overlapping features with reactive T-cells and limitations of currently available T-cell clonality assays. The description of an antibody specific for one of two mutually exclusive T-cell receptor (TCR) β-chain constant regions (TRBC1) provide an opportunity to facilitate the detection of clonal TCRαβ T-cells based on TRBC-restriction.

Methods: Twenty patients with mature T-cell neoplasms and 44 patients without evidence of T-cell neoplasia were studied.

Comprehensive Platelet Phenotypic Laboratory Testing and Bleeding History Scoring for Diagnosis of Suspected Hereditary Platelet Disorders: A Single-Institution Experience.

Objectives: Patients with hereditary/congenital platelet disorders (HPDs) have a broad range of clinical manifestations and laboratory phenotypes. We assessed the performance characteristics of the International Society on Thrombosis and Haemostasis bleeding assessment tool (ISTH-BAT) and clinically validated platelet laboratory tests for diagnosis of HPDs.

Methods: The records of 61 patients with suspected HPDs were reviewed and ISTH-BAT scores calculated.