Mapping Cell Phenomics with Multiparametric Flow Cytometry Assays

Phenomics explores the complex interactions among genes, epigenetics, symbiotic microorganisms, diet, and environmental exposure based on the physical, chemical, and biological characteristics of individuals and groups. Increasingly efficient and comprehensive phenotyping techniques have been integrated into modern phenomics-related research. Multicolor flow cytometry technology provides more measurement parameters than conventional flow cytometry. Based on detailed descriptions of cell phenotypes, rare cell populations and cell subsets can be distinguished, new cell phenotypes can be discovered, and cell apoptosis characteristics can be detected, which will expand the potential of cell phenomics research. Based on the enhancements in multicolor flow cytometry hardware, software, reagents, and method design, the present review summarizes the recent advances and applications of multicolor flow cytometry in cell phenomics, illuminating the potential of applying phenomics in future studies.

Database-Guided Analysis for Immunophenotypic Diagnosis and Follow-Up of Acute Myeloid Leukemia With Recurrent Genetic Abnormalities

Acute myeloid leukemias (AMLs) are hematologic malignancies with varied molecular and immunophenotypic profiles, making them difficult to diagnose and classify. High-dimensional analysis algorithms might increase the utility of multicolor flow cytometry for AML diagnosis and follow-up. The objective of the present study was to assess whether a Compass database-guided analysis can be used to achieve rapid and accurate diagnoses. We conducted this study to determine whether this method could be employed to pilote the genetic and molecular tests and to objectively identify different-from-normal (DfN) patterns to improve measurable residual disease follow-up in AML. Three Compass databases were built using Infinicyt 2.0 software, including normal myeloid-committed hematopoietic precursors (n = 20) and AML blasts harboring the most frequent recurrent genetic abnormalities (n = 50). The diagnostic accuracy of the Compass database-guided analysis was evaluated in a prospective validation study (125 suspected AML patients). This method excluded AML associated with the following genetic abnormalities: t(8;21), t(15;17), inv(16), and KMT2A translocation, with 92% sensitivity [95% confidence interval (CI): 78.6%–98.3%] and a 98.5% negative predictive value (95% CI: 90.6%–99.8%). Our data showed that the Compass database-guided analysis could identify phenotypic differences between AML groups, representing a useful tool for the identification of DfN patterns.

DETECTION OF MINIMAL TUMOR CELLS FOR THE DIAGNOSIS AND TREATMENT MONITORING OF CHILDREN WITH NEUROBLASTOMA

Diagnosis, treatment and designing an adequate strategy of neuroblastoma (NB) therapy in children is still a complicated tasks for pediatric oncology and hematology. One of the key aspects of NB control is detection and monitoring of minimal residual disease.The authors make a concise review of the up-to-date methods, such as immunocytochemistry, fluorescent in situ hybridization (FISH), flow cytometry, the methods of qualitative and quantitative polymerase chain reaction (PCR) to estimate mRNA (RT-PCR and QRT-PCR), which are currently used for minimal residual disease detection in patients with NB. Disialoganglioside GD2, a specific NB marker, is traditionally determined by immunocytochemistry with fluorochromes that enhance its specificity, and by flow cytometry, as well. At present, FISH test is a gold standard for evaluation of the MYCN gen status in NB. A widely used multicolor flow cytometry method allows achieving high specificity of the analysis for NB diagnosis. RT-PCR may search for various targets to reveal NB cells, however, at the moment the only accepted immune target is tyrosine hydroxylase mRNA. Moreover, the studies established that quantitative QRT-PCR has more advantages than traditional qualitative RT-PCR, since this method allows a more accurate and quantitative detection of one or several mRNAs in clinical samples. The review discusses advantages and disadvantages of the main methods currently used for minimal residual disease evaluation of NB cells, such as RT-PCR, flow cytometry, FISH, etc. Comparative studies included multicolor flow cytometry with various combinations of CD9/CD81/CD56/CD45/GD2 monoclonal antibodies, conventional RT-PCR and quantitative QRT-PCR to reveal circulating/disseminated NB cells in the clinical samples of cancer patients and healthy volunteers.The authors analyze the results of various studies that compared accuracy and sensitivity of diagnostic methods such as RT-PCR, flow cytometry, FISH and some others. Despite the advantages of each method, the authors emphasize that multicolor flow cytometry is the optimal approach for the rapid and reliable detection of minimal residual disease and micrometastases of NB.

Multiple myeloma: my highlights at ASH 2020

SummaryThe meeting focused in particular on new strategies such as chimeric antigen receptor (CAR)-T cells and bispecific antibodies. Updates of clinical trials regarding induction treatment in transplantable and non-transplantable status were presented. Furthermore, minimal residual disease negativity (MRD) or, in other words, a status characterized by no measurable disease, using standardized multicolor-flow cytometry or next-generation sequencing techniques becomes increasingly important as an endpoint in clinical trials. A subjectively assessed overview of the current contributions to the treatment of multiple myeloma is given here.

Comparison of Lethal and Nonlethal Mouse Models of Orientia tsutsugamushi Infection Reveals T-Cell Population-Associated Cytokine Signatures Correlated with Lethality and Protection

The antigenic diversity of Orientia tsutsugamushi as well as the interstrain difference(s) associated with virulence in mice impose the necessity to dissect the host immune response. In this study we compared the host response in lethal and non-lethal murine models of O. tsutsugamushi infection using the two strains, Karp (New Guinea) and Woods (Australia). The models included the lethal model: Karp intraperitoneal (IP) challenge; and the nonlethal models: Karp intradermal (ID), Woods IP, and Woods ID challenges. We monitored bacterial trafficking to the liver, lung, spleen, kidney, heart, and blood, and seroconversion during the 21-day challenge. Bacterial trafficking to all organs was observed in both the lethal and nonlethal models of infection, with significant increases in average bacterial loads observed in the livers and hearts of the lethal model. Multicolor flow cytometry was utilized to analyze the CD4+ and CD8+ T cell populations and their intracellular production of the cytokines IFNγ, TNF, and IL2 (single, double, and triple combinations) associated with both the lethal and nonlethal murine models of infection. The lethal model was defined by a cytokine signature of double- (IFNγ-IL2) and triple-producing (IL2-TNF-IFNγ) CD4+ T-cell populations; no multifunctional signature was identified in the CD8+ T-cell populations associated with the lethal model. In the nonlethal model, the cytokine signature was predominated by CD4+ and CD8+ T-cell populations associated with single (IL2) and/or double (IL2-TNF) populations of producers. The cytokine signatures associated with our lethal model will become depletion targets in future experiments; those signatures associated with our nonlethal model are hypothesized to be related to the protective nature of the nonlethal challenges.