OMIP-010: A new 10-color monoclonal antibody panel for polychromatic immunophenotyping of small hematopoietic cell samples

OMIP-106: A 30-color panel for analysis of check-point inhibitory networks in the bone marrow of acute myeloid leukemia patients

Acute myeloid leukemia (AML) is the most common form of acute leukemia diagnosed in adults. Despite advances in medical care, the treatment of AML still faces many challenges, such as treatment-related toxicities, that limit the use of high-intensity chemotherapy, especially in elderly patients. Currently, various immunotherapeutic approaches, that is, CAR-T cells, BiTEs, and immune checkpoint inhibitors, are being tested in clinical trials to prolong remission and improve the overall survival of AML patients. However, early reports show only limited benefits of these interventions and only in a subset of patients, showing the need for better patient stratification based on immunological markers. We have therefore developed and optimized a 30-color panel for evaluation of effector immune cell (NK cells, γδ T cells, NKT-like T cells, and classical T cells) infiltration into the bone marrow and analysis of their phenotype with regard to their differentiation, expression of inhibitory (PD-1, TIGIT, Tim3, NKG2A) and activating receptors (DNAM-1, NKG2D). We also evaluate the immune evasive phenotype of CD33+ myeloid cells, CD34+CD38-, and CD34+CD38+ hematopoietic stem and progenitor cells by analyzing the expression of inhibitory ligands such as PD-L1, CD112, CD155, and CD200. Our panel can be a valuable tool for patient stratification in clinical trials and can also be used to broaden our understanding of check-point inhibitory networks in AML.

OMIP - 081: A new 21-monoclonal antibody 10-color panel for diagnostic polychromatic immunophenotyping

The 10-color panel consisting of 21 monoclonal antibodies (mAbs) is developed as a one-tube panel to detect leukemia and lymphoma cells in all hematopoietic cell lineages. In particular, this tube is mentioned for a fast screening to identify aberrant cells in samples suspected for malignant cell localization and to enable comprehensive immunophenotyping of samples with low cell counts. The panel contains mAbs for selection of the populations and mAbs against target antigens on the various hematopoietic maturation stages. Due to the limited number of PMTs in most used flow cytometers for clinical purposes, stacking of conjugates in one color is needed to include all relevant markers for simultaneous analysis of the aberrant cells. The 21-mAb panel is tested on peripheral blood (PB), and bone marrow (BM) samples and enables an efficient and correct identification of hematological malignancies. This panel improves the diagnostic potential.

Orchestrating multiplexity in polychromatic science through OMIPs: A decade-old resource to empower biomedical research

As the optimized multicolor immunofluorescence panel (OMIP) platform entered its 10th anniversary since its launch, the multicolor flow cytometry landscape has changed significantly. Likewise, OMIPs have continuously evolved to cover larger panel sizes, increasing number of subpopulations profiled in a single panel, and new species. After a decade of contributions to the OMIP platform, a review of this collection, summarizing its content and purpose for the research community, is timely and due. This review provides an overview of OMIPs and a presentation of the depth and diversity of this collection of validated panels, with the expectation that readers will take advantage of them to empower and accelerate their research.

Single-Tube Flow Cytometry Assay for the Detection of Mature Lymphoid Neoplasms in Paucicellular Samples

OBJECTIVES

Flow cytometry (FC) has become a useful support for cytomorphologic evaluation (CM) of fine-needle aspirates (FNA) and serous cavity effusions (SCE) in cases of suspected non-Hodgkin lymphoma (NHL). FC results may be hampered by the scarce viability and low cellularity of the specimens.

STUDY DESIGN

We developed a single-tube FC assay (STA) that included 10 antibodies cocktailed in 8-color labeling, a cell viability dye, and a logical gating strategy to detect NHL in hypocellular samples. The results were correlated with CM and confirmed by histologic or molecular data when available.

RESULTS

Using the STA, we detected B-type NHL in 31 out of 103 hypocellular samples (81 FNA and 22 SCE). Of these, 8 were not confirmed by CM and 2 were considered to be only suspicious. The FC-negative samples had a final diagnosis of benign/reactive process (42/72), carcinoma (27/72), or Hodgkin lymphoma (3/72).

CONCLUSIONS

The STA approach allowed obtainment of maximum immunophenotyping data in specimens containing a low number of cells and a large amount of debris. The information obtained by STA can help cytomorphologists not only to recognize but also to exclude malignant lymphomas.

Novel lymphocyte screening tube using dried monoclonal antibody reagents

We previously developed a 10-color 11-antibody combination including a viability dye, to screen T-, B-, and natural killer (NK)-cell populations in blood, bone marrow, tissue, and body fluids. Recently, Beckman Coulter has introduced a line of dried reagents that, unlike liquid reagents and cocktails, require no refrigeration, titration, or manipulation before using. We evaluated custom tubes based on our standard lymphocyte screening panel, focusing on comparative analysis, ease of use, and advantages compared with our liquid reagent set. We tested 42 samples from blood (n = 15), bone marrow (n = 17), and tissue (n = 10) with the combination CD4/CD8/KAPPA/LAMBDA/CD19/CD56/CD5/CD20/CD10/CD3/CD45 and a vital dye by both methods and compared positivity and staining intensity for each antigen. Of the 42 samples, 5 were normal samples, 3 were red cell disorders, 20 were B-cell malignancies, 5 T-cell malignancies, 4 myeloid malignancies, and the remaining 5 were other diagnoses. Dried reagents gave equivalent staining intensity results to our standard panel in a variety of sample types, with diagnoses including reactive lymphocytosis, chronic lymphocytic leukemia, and various lymphomas. Our standard panel for evaluation of mature lymphoid malignancies allows rapid assessment of any sample type while providing direct assessment of viability. The dried reagent tube reduces preanalytical work, with simple addition of sample and the viability dye to the tube, saving time, reducing potential errors, and obviating need to titrate and monitor individual antibodies. With a shelf life of at least 12 months, the reagents also offer potential savings in reagent costs by reducing wastage due to expiration or tandem breakdown in standard liquid formulation.

Screening bone marrow samples for abnormal lymphoid populations and myelodysplasia-related features with one 10-color 14-antibody screening tube

BACKGROUND

We have designed one-tube 14-antibody 10-color flow cytometry (FCM) panel that would provide maximum information on lymphoid and myeloid cell subsets in bone marrow aspirates (BMA) from patients with cytopenia(s).

SAMPLES AND METHODS

BMA from 8 normal donors, from 286 non-malignant hospital controls, 92 myelodysplastic syndromes (MDS), 47 myeloproliferative neoplasms (MPN), and from 14 MDS/MPN patients were investigated. One tube 14-monoclonal antibody (MAb) 10-fluorochrome panel included: kappa+CD4 FITC, Lambda+CD8 PE, CD3 + CD14 ECD, CD34 APC, CD20+CD56 PC7, CD10 APC-A750, CD19 APC-A700, CD33 PC5.5, CD5 PB, and CD45 KO. Kappa/lambda expression was evaluated separately in CD19+, CD10+ and CD5+ B-cells. CD4+CD3+, CD8+CD3+, CD5+CD3+ T-lymphocyte subsets were enumerated. Blasts were evaluated using CD45/SSC and CD34 gating. The FCM score for MDS (sc. Ogata score) included CD34+ myeloblast and B-progenitor cluster size, myeloblast/lymphocyte CD45 expression, and granulocyte/lymphocyte SSC ratio.

RESULTS

Abnormal lymphoid populations or increased plasma cells were found in 18 patients (4%). A 43/92 BMA from MDS and 7/14 from MDS/MPN patients had score >2. Score >2 had 92.5% positive predictive value for MDS/MDS-MPN diagnosis. Negative predictive value for MDS/MDS-MPN was 83% for scores under 3 and 88% for scores under 2. All but two of normal/hospital control samples had FCM score <3 (99%). Differences in scores between MDS & MDS/MPN and the control groups were statistically significant (P < 0.0001).

CONCLUSIONS

Our one-tube FCM panel can be easily applied to screening for aberrant lymphoid populations and myelodysplasia-related features. MDS scores >2 are highly indicative of MDS or MDS-MPN.

RchyOptimyx: cellular hierarchy optimization for flow cytometry

Analysis of high-dimensional flow cytometry datasets can reveal novel cell populations with poorly understood biology. Following discovery, characterization of these populations in terms of the critical markers involved is an important step, as this can help to both better understand the biology of these populations and aid in designing simpler marker panels to identify them on simpler instruments and with fewer reagents (i.e., in resource poor or highly regulated clinical settings). However, current tools to design panels based on the biological characteristics of the target cell populations work exclusively based on technical parameters (e.g., instrument configurations, spectral overlap, and reagent availability). To address this shortcoming, we developed RchyOptimyx (cellular hieraRCHY OPTIMization), a computational tool that constructs cellular hierarchies by combining automated gating with dynamic programming and graph theory to provide the best gating strategies to identify a target population to a desired level of purity or correlation with a clinical outcome, using the simplest possible marker panels. RchyOptimyx can assess and graphically present the trade-offs between marker choice and population specificity in high-dimensional flow or mass cytometry datasets. We present three proof-of-concept use cases for RchyOptimyx that involve 1) designing a panel of surface markers for identification of rare populations that are primarily characterized using their intracellular signature; 2) simplifying the gating strategy for identification of a target cell population; 3) identification of a non-redundant marker set to identify a target cell population.