Distinct T cell subsets in adipose tissue are associated with obesity.

Adipose tissue inflammation is a driving factor for the development of obesity-associated metabolic disturbances, and a role of adipose tissue T cells in initiating the pro-inflammatory signaling is emerging. However, data on human adipose tissue T cells in obesity are limited, reflected by the lack of phenotypic markers to define tissue-resident T cell subsets. In this study, we performed a deep characterization of T cells in blood and adipose tissue depots using multicolor flow cytometry and RNA sequencing. We identified distinct subsets of T cells associated with obesity expressing the activation markers, CD26 and CCR5, and obesity-specific genes that are potentially engaged in activating pro-inflammatory pathway, including ceramide signaling, autophagy, and IL-6 signaling. These findings increase our knowledge on the heterogeneity of T cells in adipose tissue and on subsets that may play a role in obesity-related pathogenesis.

Mutations in PIGU Impair the Function of the GPI Transamidase Complex, Causing Severe Intellectual Disability, Epilepsy, and Brain Anomalies.

The glycosylphosphatidylinositol (GPI) anchor links over 150 proteins to the cell surface and is present on every cell type. Many of these proteins play crucial roles in neuronal development and function. Mutations in 18 of the 29 genes implicated in the biosynthesis of the GPI anchor have been identified as the cause of GPI biosynthesis deficiencies (GPIBDs) in humans. GPIBDs are associated with intellectual disability and seizures as their cardinal features. An essential component of the GPI transamidase complex is PIGU, along with PIGK, PIGS, PIGT, and GPAA1, all of which link GPI-anchored proteins (GPI-APs) onto the GPI anchor in the endoplasmic reticulum (ER). Here, we report two homozygous missense mutations (c.209T>A [p.Ile70Lys] and c.1149C>A [p.Asn383Lys]) in five individuals from three unrelated families. All individuals presented with global developmental delay, severe-to-profound intellectual disability, muscular hypotonia, seizures, brain anomalies, scoliosis, and mild facial dysmorphism. Using multicolor flow cytometry, we determined a characteristic profile for GPI transamidase deficiency. On granulocytes this profile consisted of reduced cell-surface expression of fluorescein-labeled proaerolysin (FLAER), CD16, and CD24, but not of CD55 and CD59; additionally, B cells showed an increased expression of free GPI anchors determined by T5 antibody. Moreover, computer-assisted facial analysis of different GPIBDs revealed a characteristic facial gestalt shared among individuals with mutations in PIGU and GPAA1. Our findings improve our understanding of the role of the GPI transamidase complex in the development of nervous and skeletal systems and expand the clinical spectrum of disorders belonging to the group of inherited GPI-anchor deficiencies.

[Establishment of 14-Color Panel for Determining Leukocyte Subsets in Human Peripheral Blood with Flow Cytometry].

OBJECTIVE: To establish a 14-color flow cytometry protocol for the examination of leukocyte subsets in human peripheral blood. METHODS: We used cell membrane surface antibodies CD45, CD3, CD4, CD8, CD19, CD56, CD16, CD14, CD25, CD127, HLA-DR, CD123, CD11c and nucleus staining dye DAPI to establish a 14-color flow cytometry assay to determine the major cell subsets in human peripheral blood. We collected peripheral blood specimens from healthy volunteers to test for antibody titers and optimal photomultiplier tube (PMT) voltage, and to conduct single-color staining and fluorescence minus one control staining. After determining the test method and test conditions, the peripheral blood samples of 18 healthy volunteers were analyzed. RESULTS: According to the cell classification and staining index, optimal antibody mass concentrations selected were as follows: CD25 and CD127 at 8.0 µg/mL, CD45, CD3, CD14 and CD123 at 4.0 µg/mL, CD8, CD19, CD56, CD16, HLA-DR and CD11c at 2.0 µg/mL, CD4 at 1.0 µg/mL and DAPI at 0.1 µg/mL. The detection voltages for CD45, CD3, CD4, CD8, CD19, CD56, CD16, CD14, CD25, CD127, HLA-DR, CD123, CD11c and DAPI were 450 V, 410 V, 400 V, 550 V, 405 V, 500 V, 520 V, 550 V, 550 V, 400 V, 450 V, 400 V, 580 V, and 300 V, respectively. The appropriate fluorescence compensation was determined by single-color staining and fluorescence minus one controls. The 14-color flow cytometry panel was established to analyze the main subsets of leukocytes in human peripheral blood, and peripheral blood samples from 18 healthy adults were examined, obtaining the percentages of each subset of peripheral blood leukocytes and the immunophenotypes of the main subsets. CONCLUSION: We established a 14-color panel for determining leukocyte subsets in human peripheral blood by flow cytometry, which produced stable and reliable results and was easy to operate.

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.

Assessment of chilling injury in hypothermic stored boar spermatozoa by multicolor flow cytometry.

Hypothermic storage of boar semen may allow antibiotic-free semen preservation but is limited due to chilling sensitivity of boar spermatozoa. Progress in this area requires sensitive tools to detect chilling injury. Therefore, multiparameter flow cytometry panels were evaluated to ascertain whether they are useful tools for identifying sublethal damage of sperm function at a single cell level, thus considering the high intrinsic sperm heterogeneity in a sample. The first fluorochrome panel consisted of Hoechst 33342 to identify DNA-containing events, Yo-Pro 1 to detect viability, merocyanine 540 to describe membrane fluidity, and PNA-Alexa Fluor™ 647 to identify acrosomic integrity. The second fluorochrome panel consisted of SiR700-DNA to identify DNA-containing events, JC-1 to characterize the mitochondrial transmembrane potential (MMP), and Calbryte 630 to assess the intracellular calcium level. Extended boar semen was stored either at 17°C (control) or 5°C (chilled). It is shown that chilling increased membrane fluidity in the viable (Yo-Pro 1 negative) sperm population at 24 h (p < 0.05). At 144 h, the viable, acrosomic intact sperm population with low membrane fluidity was similar for both storage temperatures. Moreover, chilling reduced the main sperm population with high MMP, medium fluorescence for JC-1 monomer and low intracellular calcium level (p < 0.05). However, after in vitro sperm capacitation, this population did not differ between the two storage temperatures. Exemplary computational data visualization in t-distributed stochastic neighbor embedding (t-SNE) maps and moving radar plots revealed similar subpopulations as identified by three-dimensional stacked bar charts. In conclusion, sperm surviving an initial chilling injury withstand long-term storage and respond in a similar manner to capacitation conditions as sperm stored conventionally at 17°C. Multicolor flow cytometry is a valuable tool for detecting chilling-induced alterations of cell function in sperm subpopulations.

Pre-transplant minimal residual disease assessment and transplant-related factors predict the outcome of acute myeloid leukemia patients undergoing allogeneic stem cell transplantation.

We studied pretransplant minimal residual disease (MRD) in 224 patients (median age 44 years; range 17-65) with acute myeloid leukemia (AML) undergoing allogeneic stem cell transplant (HSCT) in complete remission. MRD was evaluated on marrow samples using multicolor flow cytometry and assessment of WT1 gene expression. Both methods showed a strong prognostic value and their combination allowed the identification of three groups of patients with different risk of relapse. In multivariate analysis, combined MRD was the only predictor of cumulative incidence of relapse, regardless of donor type, conditioning regimen, first or second CR at HSCT, HSCT year, and ELN risk group. Multivariate regression model showed that only negative combined MRD status (P < .001) and myeloablative conditioning (P = .004) were independently associated with better OS. Among MRD-positive patients, a reduced incidence of relapse was observed in patients receiving haplo transplant (P < .05) and in patients who showed grade II-IV aGVHD (P < .03). In patients with negative combined MRD, the intensity of conditioning regimen did not affect the overall favorable outcome. We suggest that pretransplant MRD evaluation combined with transplant-related factors can identify AML patients at higher risk for relapse and might help in defining the overall transplant strategy.

Role of pre-transplant MRD level detected by flow cytometry in recipients of allogeneic stem cell transplantation with AML.

OBJECTIVES AND METHODS: We analyzed the impact of pretransplant MRD level in bone marrow measured by flow cytometry using "different from normal" method on outcomes for 189 AML patients (108 males; median age, 58 (21-80) years). All patients were subdivided into negative (n = 96), "low" (0.1%-0.5%, n = 32), and "high" MRD (>0.5%, n = 61) groups. RESULTS: In multivariate analysis, the hazard ratios for "high" and "low" MRD levels related to MRD negativity were 7.9 (95% CI 3.5-18.1, P < .001) and 5.4 (95% CI 2.1-14, P = .0058) for relapse; 2.3 (95% CI 1.3-4.1, P = .006) and 1.6 (95% CI 0.82-3.3, P = .16) for OS; and 2.8 (95% CI 1.7-4.7, P < .001) and 2.2 (95% CI 1.1-4.2, P = .02) for LFS, respectively. We found no significant impact of "low" MRD level on relapses (0.68, 95% CI 0.33-1.4, P = .30), OS (0.72, 95% CI: 0.36-1.5, P = .36) and LFS (0.79, 95% CI: 0.42-1.5, P = .46) related to "high" MRD group. CONCLUSIONS: Presence of detectable MRD was indicative for a high relapse risk, low LFS and OS. "Low" MRD level showed no significant impact on relapse, LFS and OS related to "high" MRD group.

Induced pluripotent stem cells from urine of Duchenne muscular dystrophy patients.

BACKGROUND: The most common muscular dystrophy, Duchenne muscular dystrophy (DMD), is a lethal, X-linked disorder with no widespread cure. Worldwide, in vitro studies involving new, mutation-specific cures and regenerative therapies are employing disease-specific patient-specific cells. However, these may not be completely relevant for Pakistani children because of the human genome diversities and geographic variation in mutation type and frequency. Therefore, this study aimed to generate DMD induced pluripotent stem cells (iPSCs) from the urine of Pakistani children with DMD, to serve as a precious source of differentiated cells, such as Pakistani DMD-cardiomyocytes, for future disease-modelling, drug testing, and gene therapy. METHODS: Urine-derived cells (UDCs) isolated from mid-stream urine underwent molecular characterization and cellular reprogramming towards iPSCs using the episomal vector system followed by molecular profiling of the iPSCs. RESULTS: Colonies of elongated and spindle-shaped or rounded rice-grain like UDCs were spotted 4-7 days after plating and expanded rapidly with a second passage at 2-3 weeks. Multicolor flow cytometry confirmed the expression of mesenchymal stem-cell markers. The reprogramed iPSCs consisted of colonies of round, tightly-packed cells with large nuclei that were positively fluorescent for the pluripotency markers octamer binding transcription factor-4 (OCT-4), tumour resistance antigen 1-60 (TRA-1-60), and stage specific embryonic 4 antigen (SSEA-4), but not for the negative pluripotency marker SSEA-1. To the best of our knowledge, this was the first time DMD-iPSCs have been generated for Pakistani children. CONCLUSION: This integration-free, feeder-free, efficient, and reproducible reprogramming method employed UDCs. Urine is a low-cost, non-invasive, painless, and repeatable source of rapidly expandable cells from children and morbid individuals for obtaining autologous cells for drug-assays and disease-modelling, suitable for DMD and other debilitating diseases.

Decrease of Non-Classical and Intermediate Monocyte Subsets in Severe Acute SARS-CoV-2 Infection.

In patients with severe SARS-CoV-2 infection, the development of cytokine storm induces extensive lung damage, and monocytes play a role in this pathological process. Non-classical (NC) and intermediate (INT) monocytes are known to be involved during viral and bacterial infections. In this study, 30 patients with different manifestations of acute SARS-CoV-2 infection were investigated with a flow cytometric study of NC, INT, and classical (CL) monocytes. Significantly reduced NC and INT monocytes and a downregulated HLA-DR were found in acute patients with severe SARS-CoV-2 symptoms. Conversely in patients with moderate symptoms NC and INT monocytes and CD11b expression were increased. © 2020 International Society for Advancement of Cytometry.

FACS single cell index sorting is highly reliable and determines immune phenotypes of clonally expanded T cells.

FACS index sorting allows the isolation of single cells with retrospective identification of each single cell's high-dimensional immune phenotype. We experimentally determine the error rate of index sorting and combine the technology with T cell receptor sequencing to identify clonal T cell expansion in aplastic anemia bone marrow as an example.

Flow-cytometric minimal residual disease monitoring in blood predicts relapse risk in pediatric B-cell precursor acute lymphoblastic leukemia in trial AIEOP-BFM-ALL 2000.

BACKGROUND: Flow-cytometric monitoring of minimal residual disease (MRD) in bone marrow (BM) during induction of pediatric patients with acute lymphoblastic leukemia (ALL) is widely used for outcome prognostication and treatment stratification. Utilizing peripheral blood (PB) instead of BM might be favorable, but data on its usefulness are scarce. PROCEDURE: We investigated 1303 PB samples (days 0, 8, 15, 33, and 52) and 285 BMs (day 15) from 288 pediatric ALL patients treated in trial AIEOP-BFM ALL 2000. MRD was assessed by four-color flow cytometry and evaluated as relative, absolute, and kinetic result. RESULTS: In B-ALL only, PB measures from early time points correlated with relapse incidence (CIR). Best separation occurred at threshold <1 blast/µL at day 8 (5-year CIR 0.02 ± 0.02 vs 0.12 ± 0.03; P = 0.044). Patients with highest relapse risk were not distinguishable, but PB-MRD at days 33 and 52 correlated with prednisone response and postinduction BM-MRD by PCR (P < 0.001). Kinetic assessment did not convey any advantage. In multivariate analysis including day 15 BM-MRD, PB-MRD measures lost statistical power. CONCLUSIONS: In summary, PB-MRD in pediatric B-ALL correlates with outcome and risk parameters, but its prognostic significance is not strong enough to substitute for BM assessment in AIEOP-BFM trials. It might, however, be valuable in treatment environments not using multifaceted risk stratification with other MRD measures.

Clinical Use of Measurable Residual Disease in Acute Myeloid Leukemia.

OPINION STATEMENT: Treatment of acute myeloid leukemia (AML) remains a high-risk venture for the patient suffering from the disease. There is a real risk of succumbing to the treatment rather than the disease, and even so, cure is much less than certain. Since the establishment of complete remission as a prerequisite for cure in the 1960s, a number of years passed before advanced techniques for detecting minute amounts of disease matured sufficiently for clinical implementation. The two main techniques for detection of measurable residual disease (MRD) remain qPCR and multicolor flow cytometry. When performed in expert laboratories, both these modalities offer treating physicians excellent opportunity to follow the amount of residual disease upon treatment and offer unparalleled prognostication. In some AML and age group subsets, evidence now exist to support the choice of both proceeding to allogeneic transplant and not doing so. In other AML subgroups, MRD has sufficient discriminative power to identify patients likely to benefit from allogeneic transplant and patients likely not to. After treatment or transplantation, follow-up by molecular techniques can, with high certainty, predict relapse months before bone marrow function deterioration. On the other hand, options upon so-called molecular relapse are less well tested but recent evidence supports the use of azacitidine both in transplanted patients and patients consolidated with chemotherapy. In conclusion, MRD testing during treatment is a superb prognosticator and a major tool when choosing whether a patient should be transplanted or not. The exact use of MRD testing after treatment is less well defined but evidence is mounting for the instigation of treatment upon rising MRD levels (pre-emptive treatment) before morphologically detectable relapse.

Development of a Modular Assay for Detailed Immunophenotyping of Peripheral Human Whole Blood Samples by Multicolor Flow Cytometry.

The monitoring of immune cells gained great significance in prognosis and prediction of therapy responses. For analyzing blood samples, the multicolor flow cytometry has become the method of choice as it combines high specificity on single cell level with multiple parameters and high throughput. Here, we present a modular assay for the detailed immunophenotyping of blood (DIoB) that was optimized for an easy and direct application in whole blood samples. The DIoB assay characterizes 34 immune cell subsets that circulate the peripheral blood including all major immune cells such as T cells, B cells, natural killer (NK) cells, monocytes, dendritic cells (DCs), neutrophils, eosinophils, and basophils. In addition, it evaluates their functional state and a few non-leukocytes that also have been associated with the outcome of cancer therapy. This DIoB assay allows a longitudinal and close-meshed monitoring of a detailed immune status in patients requiring only 2.0 mL of peripheral blood and it is not restricted to peripheral blood mononuclear cells. It is currently applied for the immune monitoring of patients with glioblastoma multiforme (IMMO-GLIO-01 trial, NCT02022384), pancreatic cancer (CONKO-007 trial, NCT01827553), and head and neck cancer (DIREKHT trial, NCT02528955) and might pave the way for immune biomarker identification for prediction and prognosis of therapy outcome.

Deciphering the impact of parameters influencing transgene expression kinetics after repeated cell transduction with integration-deficient retroviral vectors.

Lentiviral and gammaretroviral vectors are state-of-the-art tools for transgene expression within target cells. The integration of these vectors can be deliberately suppressed to derive a transient gene expression system based on extrachromosomal circular episomes with intact coding regions. These episomes can be used to deliver DNA templates and to express RNA or protein. Importantly, transient gene transfer avoids the genotoxic side effects of integrating vectors. Restricting their applicability, episomes are rapidly lost upon dilution in dividing target cells. Addressing this limitation, we could establish comparably stable percentages of transgene-positive cells over prolonged time periods in proliferating cells by repeated transductions. Flow cytometry was applied for kinetic analyses to decipher the impact of individual parameters on the kinetics of fluoroprotein expression after episomal retransduction and to visualize sequential and simultaneous transfer of heterologous fluoroproteins. Expression windows could be exactly timed by the number of transduction steps. The kinetics of signal loss was affected by the cell proliferation rate. The transfer of genes encoding fluoroproteins with different half-lives revealed a major impact of protein stability on temporal signal distribution and accumulation, determining optimal retransduction intervals. In addition, sequential transductions proved broad applicability in different cell types and using different envelope pseudotypes without receptor overload. Stable percentages of cells coexpressing multiple transgenes could be generated upon repeated coadministration of different episomal vectors. Alternatively, defined patterns of transgene expression could be recapitulated by sequential transductions. Altogether, we established a methodology to control and adjust a temporally defined window of transgene expression using retroviral episomal vectors. Combined with the highly efficient cell entry of these vectors while avoiding integration, the developed technology is of great significance for a broad panel of applications, including transcription-factor-based induced cell fate conversion and controlled transfer of genetically encoded RNA- or protein-based drugs.

Novel method to characterize immune cells from human prostate tissue.

BACKGROUND: Benign prostatic hyperplasia (BPH) is the most common benign adenoma and prostate cancer is the most frequent malignancy in men over 50 years of age in the Western world, where it remains a significant health problem. Prostate lesions are known to contain immune cells, which may contribute to the immune control of tumor progression. However, due to their low numbers and restricted access to necessary material it is difficult to isolate immune cells from prostate tissue to characterize their immunological features. METHODS: An efficient and robust method was developed to process prostate tissue and isolate immune cells for phenotypic analysis by multicolor flow cytometry as downstream application. Fresh prostate tissue from 11 patients undergoing surgery for bladder outlet obstruction due to BPH was processed to evaluate the number, viability, yield, and frequency of various immune cell types. RESULTS: The presented method does not include enzymatic digestion nor incubation steps at 37 °C, increasing cellular viability and avoiding possible phenotypic modification. Various immune cell populations were detected in all patient samples and the median cellular viability was 90%. The number of detected events of individual cell populations varied between patients. The median frequency of different immune cell populations also varied, being 87% for the CD3- and 15% for the CD3+ cell population. CONCLUSIONS: This novel method will allow the phenotypic characterization of immune cell populations present in tumor tissue of prostate cancer patients and promote development of novel approaches to immunotherapy of the disease.

Immunophenotypic portrait of leukemia-associated-phenotype markers in B acute lymphoblastic leukemia.

BACKGROUND: Multiparametric flow cytometry (MFC) is an essential diagnostic tool in B acute lymphoblastic leukemia (B ALL) to determine the B-lineage affiliation of the blast population and to define their complete immunophenotypic profile. Most MFC strategies used in routine laboratories include leukemia-associated phenotype (LAP) markers, whose expression profiles can be difficult to interpret. The aim of our study was to reach a better understanding of 7 LAP markers' landscape in B ALL: CD9, CD21, CD66c, CD58, CD81, CD123, and NG2. METHODS: Using a 10-color MFC approach, we evaluated the level of expression of 7 LAP markers including CD9, CD21, CD66c, CD58, CD81, CD123, and NG2, at the surface of normal peripheral blood leukocytes (n = 10 healthy donors), of normal precursor B regenerative cells (n = 40 uninvolved bone marrow samples) and of lymphoblasts (n = 100 peripheral blood samples or bone marrow samples from B ALL patients at diagnosis). The expression profile of B lymphoblasts was analyzed according the presence or absence of recurrent cytogenetic aberrations. The prognostic value of the 7 LAP markers was examined using Maxstat R algorithm. RESULTS: In order to help the interpretation of the MFC data in routine laboratories, we first determined internal positive and negative populations among normal leukocytes for each of the seven evaluated LAP markers. Second, their profile of expression was evaluated in normal B cell differentiation in comparison with B lymphoblasts to establish a synopsis of their expression in normal hematogones. We then evaluated the frequency of expression of these LAP markers at the surface of B lymphoblasts at diagnosis of B ALL. CD9 was expressed in 60% of the cases, CD21 in only 3% of the cases, CD58 in 96% of the cases, CD66c in 45% of the cases, CD81 in 97% of the cases, CD123 in 72% of the cases, and NG2 in only 2% of the cases. We confirmed the interest of the CD81/CD58 MFI expression ratio as a way to discriminate hematogones from lymphoblasts. We observed a significant lower expression of CD9 and of CD81 at the surface of B lymphoblasts with a t(9;22)(BCR-ABL) in comparison with B lymphoblasts without any recurrent cytogenetic alteration (p = 0.0317 and p = 0.0011, respectively) and with B lymphoblasts harboring other cytogenetic recurrent abnormalities (p = 0.0032 and p < 0.0001, respectively). B lymphoblasts with t(1;19) at diagnosis significantly overexpressed CD81 when compared with B lymphoblasts with other recurrent cytogenetic abnormalities or without any recurrent alteration (p = 0.0001). An overexpression of CD58 was also observed in the cases harboring this abnormal cytogenetic event, when compared with B lymphoblasts with other recurrent cytogenetic abnormalities (p = 0.030), or without any recurrent alteration (p = 0.0002). In addition, a high expression of CD123, of CD58 and of CD81 was associated with a favorable prognosis in our cohort of pediatric and young adult B ALL patients. We finally built a risk score based on the expression of these 3 LAP markers, this scoring approach being able to split these patients into a high-risk group (17%) and a better outcome group (83%, p < 0.0001). CONCLUSION: The complexity of the phenotypic signature of lymphoblasts at diagnosis of B ALL is illustrated by the variability in the expression of LAP antigens. Knowledge of the expression levels of these markers in normal leukocytes and during normal B differentiation is crucial for an optimal interpretation of diagnostic cytometry results and serves as a basis for the biological follow-up of B ALL.

Rapid depletion of CD20+ B and T cells following ofatumumab therapy onset.

BACKGROUND: The humanized monoclonal anti-CD20-antibody ofatumumab is highly effective in treating relapsing multiple sclerosis (MS). OBJECTIVE: This study aimed to investigate the immanent effect of ofatumumab on the peripheral immune system, particularly targeting B and T cells expressing CD20. METHODS: Blood samples of 53 MS patients receiving ofatumumab were collected prior to first application and after one week, two weeks and three months. Multicolor flow cytometry was used to phenotype peripheral blood mononuclear cells, and immunoglobulin (Ig) concentrations were measured by nephelometry. RESULTS: Among CD20+ lymphocytes, 13 % co-expressed CD3 (identifying them as CD3+CD20+ T lymphocytes), with a noticeable shift in the CD4/CD8-ratio towards CD8+ T cells. One week after administering ofatumumab, a significant reduction of CD20+ lymphocytes with complete depletion of CD3+CD20+ T lymphocytes was observed, persisting during the investigation period. During the treatment, IgM levels showed a slight but significant decrease, whereas IgA and IgG levels remained stable. CONCLUSION: Ofatumumab effectively depletes CD20+ lymphocytes already after the first administration. This depletion affects not only B cells, but also a small proportion of T cells (CD3+CD20+), affirming the hypothesis that the anti-inflammatory effects of CD20+ cell depletion might extend to the reduction of CD3+CD20+ T lymphocytes.

[Establishment of a 21-color Panel for the Detection of Immune Cell Subsets 
in Human Non-small Cell Lung Cancer Tumor Tissues with Flow Cytometry].

BACKGROUND: With the rise of multicolor flow cytometry, flow cytometry has become an important means to detect the immune microenvironment of lung cancer, but most of them are used to detect the proportion of cell subsets or the function of major cell subsets, and they cannot be detected at the same time. Therefore, a reliable 21-color flow cytometry protocol was established to detect the immune cell subsets in human non-small cell lung cancer (NSCLC) tumor tissues. METHODS: Cell membrane surface antibodies cluster of differentiation (CD)45, CD3, CD19, CD4, CD8, programmed cell death 1 (PD-1), CD39, CD103, CD25, CD127, chemokine receptor 8 (CCR8), CD56, CD11c, human leukocyte antigen (HLA)-DR, CD38, CD27, CD69, CD62L, CD45RA, CCR7 and nucleic acid dye L/D were used to develop the protocol. Firstly, antibody titration experiments, voltage optimization, subtraction of one color staining and single color staining experiments were carried out for each antibody, and after the experimental conditions and detection schemes were determined, the feasibility of the scheme was verified by using peripheral blood mononuclear cells (PBMCs) specimens of six healthy adult volunteers. Tumor tissue samples from 6 NSCLC patients were tested and analyzed. RESULTS: The established 21-color flow cytometry protocol was used to detect the tumor tissue samples of 6 NSCLC patients, and the proportion of each cell subset in lung cancer tissue, as well as the immunophenotype and differentiation of the main cell population, were analyzed. CONCLUSIONS: The successfully established 21-color flow cytometry protocol is suitable for the detection of PBMCs and NSCLC tissue samples, which provides an effective new idea for monitoring the immune microenvironment status in lung cancer.

CD38, CD39, and BCL2 differentiate disseminated forms of high-grade B-cell lymphomas in biological fluids from Burkitt lymphoma and diffuse large B-cell lymphoma.

High-grade B-cell lymphomas (HGBCL) represent a heterogeneous group of very rare mature B-cell lymphomas. The 4th revised edition of the WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues (WHO-HAEM) previously defined two categories of HGBCL: the so-called double-hit (DHL) and triple-hit (THL) lymphomas, which were related to forms harboring MYC and BCL2 and/or BCL6 rearrangements, and HGBCL, NOS (not otherwise specified), corresponding to entities with intermediate characteristics between diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL), without rearrangement of the MYC and BCL2, and/or BCL6 genes. In the 5th edition of the WHO-HAEM, DHL with MYC and BCL2 rearrangements or THL were reassigned as DLBCL/HGBCL with MYC and BCL2 rearrangements (DLBCL/HGBL-MYC/BCL2), whereas the category HGBCL, NOS remains unchanged. Characterized by an aggressive clinical presentation and a poor prognosis, HGBCL is often diagnosed at an advanced, widespread stage, leading to potential disseminated forms with a leukemic presentation, or spreading to the bone marrow (BM) or other biological fluids. Flow cytometric immunophenotypic study of these disseminated cells can provide a rapid method to identify HGBCL. However, due to the scarcity of cases, only limited data about the immunophenotypic features of HGBCL by multiparametric flow cytometry are available. In addition, identification of HGBCL cells by this technique may be challenging due to clinical, pathological, and biological features that can overlap with other distinct lymphoid malignancies, including Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), and even B acute lymphoblastic leukemia (B-ALL). In this study, we aimed to characterize the detailed immunophenotypic portrait of HGBCL, evaluating by multiparametric flow cytometry (MFC) the expression of 26 markers on biological samples obtained from a cohort of 10 newly-diagnosed cases and comparing their level of expression with normal peripheral blood (PB) B lymphocytes (n = 10 samples), tumoral cells from patients diagnosed with B-ALL (n = 30), BL (n = 13), or DLBCL (n = 22). We then proposed a new and simple approach to rapidly distinguish disseminated forms of HGBCL, BL, and DLBCL, using the combination of MFC data for CD38, BCL2, and CD39, the three most discriminative markers explored in this study. We finally confirmed the utility of the scoring system previously proposed by Khanlari to distinguish HGBCL cells from B lymphoblasts of B-ALL. In conclusion, we described a distinct immunophenotypic portrait of HGBCL cells and proposed a strategy to differentiate these cells from other aggressive B lymphoma entities in biological samples.

Multicolor flow cytometric immunophenotyping is highly sensitive and specific in identifying aberrant mast cells in the diagnostic workup of systemic mastocytosis.

OBJECTIVES: Flow cytometric immunophenotyping (FCI) is a fast and sensitive method for characterizing hematolymphoid neoplasms. It is not widely used in the workup of systemic mastocytosis (SM), in part because of the technical challenges and in part because the utility of FCI in assessing mast cells is not well understood. The objectives of this study were to assess the diagnostic utility of FCI in establishing a diagnosis of SM and distinguishing SM from nonneoplastic mast cells and to examine the immunophenotypic findings among SM subtypes. METHODS: We performed FCI on bone marrow samples suspicious for SM using a panel consisting of CD2, CD25, CD30, CD45, CD117, and HLA-DR. RESULTS: The cohort included 88 SM cases: 67 without an associated hematologic neoplasm (AHN) (PureSM) and 21 with an AHN (SM-AHN). We also assessed 40 normal/reactive controls. Overall, FCI was adequate for interpretation in 87 of 88 (99%) cases and detected at least 1 immunophenotypic aberrancy in 100% of SM cases. CD2, CD25, and CD30 were positive in 78%, 98%, and 90% of SM cases vs 0%, 13%, and 13% of cases with normal/reactive mast cells (P < .0001 for all). Two or 3 abnormalities were observed in 92% of SM cases but not in normal/reactive mast cells. Among SM cases, SM-AHN showed statistically significant less CD2 (38% vs 91%, P < .0001) and less co-expression of all 3 aberrant markers (CD2, CD25, and CD30 positive in 38% vs 86% of cases; P < .0001) than PureSM. Immunohistochemical analysis showed consistently weaker or focal expression of CD2, CD25, and CD30 than FCI, with CD2 and CD30 being falsely negative in 40% and 50% cases, respectively. A KIT D816V mutation was detected in 67% of PureSM cases and 76% of SM-AHN cases. CONCLUSIONS: Flow cytometric immunophenotyping is a quick, sensitive, high-yield tool for evaluating the immunophenotype of mast cells. An abnormal FCI finding should prompt careful histologic evaluation and sensitive KIT D816V mutation testing to address the possibility of SM. CD2, CD25, and CD30 are important markers for the detection of immunophenotypic aberrancy of mast cells, and their frequencies of aberrancy differ across SM subtypes.