Multiparameter Flow Cytometry Research Articles

Mass spectrometry–based assessment of M protein in peripheral blood during maintenance therapy in multiple myeloma

AbstractMass spectrometry (MS) can detect multiple myeloma–derived monoclonal proteins in the peripheral blood (PB) with high sensitivity, potentially serving as a PB assay for measurable residual disease (MRD). This study evaluated the significance of PB MS MRD negativity during posttransplant therapy in patients with newly diagnosed multiple myeloma. Serum samples from 138 patients treated in the phase 3 ATLAS trial of posttransplant maintenance with either carfilzomib, lenalidomide, and dexamethasone, or with lenalidomide alone were analyzed using EXENT MS methodology. We established feasibility of measuring MRD by MS in the PB in the posttransplant setting, despite unavailability of pretreatment calibration samples. There was high agreement between MRD by MS in the PB and paired bone marrow (BM) MRD results at the 10–5 threshold, assessed by either next-generation sequencing (NGS) or multiparameter flow cytometry (MFC) (70% and 67%, respectively). Agreement between PB MS and both BM MRD methods was lowest early after transplant and increased with time. MS negativity was associated with improved progression-free survival (PFS), which, in landmark analysis, reached statistical significance after 18 cycles after transplant. Combined PB/BM MRD negativity by MFC or NGS was associated with superior PFS compared with MRD negativity by only 1 modality. Sustained MS negativity carried similar prognostic performance to sustained BM MRD negativity at the 10–5 threshold. Overall, posttransplant MS assessment was feasible and provided additional prognostic information to BM MRD negativity. Further studies are needed to confirm the role and optimal timing of MS in disease evaluation algorithms. The ATLAS trial is registered at www.clinicaltrials.gov as #NCT02659293.

Expression of CD39 is associated with T cell exhaustion in ovarian cancer and its blockade reverts T cell dysfunction

ABSTRACT Immune exhaustion is a hallmark of ovarian cancer. Using multiparametric flow cytometry, the study aimed to analyze protein expression of novel immunological targets on CD3+ T cells isolated from the peripheral blood (n = 20), malignant ascites (n = 16), and tumor tissue (n = 6) of patients with ovarian cancer (OVCA). The study revealed an increased proportion of effector memory CD8+ T cells in OVCA tissue and malignant ascites. An OVCA-characteristic PD-1high CD8+ T cell population was detected, which differed from PD-1lowCD8+ T cells by increased co-expression of TIGIT, CD39, and HLA-DR. In addition, these OVCA-characteristic CD8+ T cells showed reduced expression of the transcription factor TCF-1, which may also indicate reduced effector function and memory formation. On the contrary, the transcription factor TOX, which significantly regulates terminal T cell-exhaustion, was found more frequently in these cells. Further protein and gene analysis showed that CD39 and CD73 were also expressed on OVCA tumor cells isolated from solid tumors (n = 14) and malignant ascites (n = 9). In the latter compartment, CD39 and CD73 were also associated with the expression of the “don’t eat me” molecule CD24 on tumor cells. Additionally, ascites-derived CD24+EpCAM+ tumor cells showed a higher frequency of CD39+ or CD73+ cells. Furthermore, CD39 expression was associated with unfavorable clinical parameters. Expression of CD39 on T cells was upregulated through CD3/CD28 stimulation and its blockade by a newly developed nanobody construct resulted in increased proliferation (eFluor), activation (CD25 and CD134), and production of cytotoxic cytokines (IFN-γ, TNF-α, and granzyme-B) of CD8+ T cells.

Comparison of three machine learning algorithms for classification of B-cell neoplasms using clinical flow cytometry data.

Multiparameter flow cytometry data is visually inspected by expert personnel as part of standard clinical disease diagnosis practice. This is a demanding and costly process, and recent research has demonstrated that it is possible to utilize artificial intelligence (AI) algorithms to assist in the interpretive process. Here we report our examination of three previously published machine learning methods for classification of flow cytometry data and apply these to a B-cell neoplasm dataset to obtain predicted disease subtypes. Each of the examined methods classifies samples according to specific disease categories using ungated flow cytometry data. We compare and contrast the three algorithms with respect to their architectures, and we report the multiclass classification accuracies and relative required computation times. Despite different architectures, two of the methods, flowCat and EnsembleCNN, had similarly good accuracies with relatively fast computational times. We note a speed advantage for EnsembleCNN, particularly in the case of addition of training data and retraining of the classifier.

Flow cytometry for meningeal infiltration in B acute lymphoblastic leukemia in a low middle income country.

Meningeal infiltration in children with B acute lymphoblastic leukemia is one of the most serious complications. Timely diagnosis not only significantly enhances treatment efficacy but also leads to improve patient outcome and reduce risk of relapse. This is particularly crucial in low to middle income countries facing health constraints, where optimizing resources is essential. Conventional cytology (CC) study of cerebrospinal fluid (CSF) is considered in different countries to be the Gold-standard despite its low sensitivity (< 50%). The study of CSF by multiparametric flow cytometry (MFC) appears to be an alternative. The aim of our study was to assess MFC analytical performance compared with CC. Our cross sectional study was conducted over a six-month period in the biological hematology department. CSF samples underwent analysis for the presence of blasts using both CC and MFC. Cytological slides of the CSF were prepared by cytocentrifugation in a Shandon Cytospin 4™. Flow cytometric analysis was performed on the BD FACSLyric™ flow cytometer. All statistical analyses were performed using SPSS version 21.0 (SPSS Inc.). Agreement between the two methods was made using the Kappa index and χ2 test. This study was approved by the local ethics committee. Sixty CSF samples from 39 children with B acute lymphoblastic leukemia were analyzed. Meningeal infiltration was detected respectively in 20% of cases by MFC and 5% of cases by CC, with a significant difference p = 0.006. Comparing the two methods, the Kappa coefficient was 0.35, indicating weak agreement between the two methods. Moreover, MFC positivity was higher even for hypocellular samples. Of the 51 hypocellular samples, eight were positive by MFC while they were negative by CC. MFC shows better sensitivity while retaining good specificity for the detection of meningeal involvement. MFC could therefore be a complementary method to CC for detecting blast cells in the central nervous system.

Detection of clonal plasma cells in POEMS syndrome using multiparameter flow cytometry

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein [M-protein], and skin changes) is a rare systemic disorder characterized by various symptoms caused by underlying plasma cell (PC) dyscrasia. Detection of monoclonal PCs is mandatory for the diagnosis of POEMS syndrome; however, the usefulness of EuroFlow-based next-generation flow cytometry (EuroFlow-NGF) in POEMS syndrome for detecting monoclonal PCs in bone marrow (BM) and the gating strategy suitable for flow cytometry study of POEMS syndrome remain unknown. We employed EuroFlow-NGF-based single-tube eight-color multiparameter flow cytometry (MM-flow) and established a new gating strategy (POEMS-flow) to detect the monoclonal PCs in POEMS syndrome, gating CD38 broadly from dim to bright and CD45 narrowly from negative to dim compared to MM-flow. MM-flow detected monoclonal PCs in 9/25 (36.0%) cases, including 2/2 immunofixation electrophoresis (IFE)-negative cases (100%). However, POEMS-flow detected monoclonal PCs in 18/25 cases (72.0%), including 2/2 IFE-negative cases (100%). POEMS-flow detected monoclonal PCs with immunophenotypes of CD19− in 17/18 (94.4%). In six cases where post-treatment samples were available, the size of the clones was significantly reduced after the treatment (P = 0.031). POEMS-flow can enhance the identification rate of monoclonal PCs in POEMS syndrome and become a valuable tool for the diagnosis of POEMS syndrome.

Peripheral blood quantitation of CD26 positive leukemic stem cells as a predictor of tyrosine kinase inhibitor response in chronic myeloid leukemia.

Leukemic stem cells (LSCs) are the transcriptionally low/silent cells which are resistant to the tyrosine kinase inhibitor. These have been found to play a pivotal role in disease relapse in chronic myeloid leukemia (CML) cases. The present study evaluated the correlation of absolute CML-LSC count in the peripheral blood (PB) at diagnosis and achievement of major molecular response (MMR) at 12 months in patients of CML-CP. This was a prospective, observational, non-interventional single center study including newly diagnosed adult (>18 yrs) CML-CP patients. Absolute CD26 + CML-LSC quantification was done by multiparametric flow cytometry. Patients were treated with Imatinib treatment and subsequently monitored at 3-month intervals for BCR::ABL transcript levels. MMR was defined as a BCR::ABL1 transcript level of less than 0.1% on international scale. A total of 89 patients were enrolled in the study out of which 40.5% achieved MMR at 12 months. There was a significant difference in the median absolute CML-LSC count of the patients who achieved MMR at 12 months as compared to those who did not (58.5 vs 368.1 cells/μL; p value <0.001). Using a ROC analysis, a count of <165.69 CML LSC/μL was identified to have a sensitivity of 83.8% and specificity of 72.4%, in predicting the MMR at 12 months. Absolute CML-LSC count at diagnosis in the PB predicts the MMR achievement at 12 months. An absolute count of less than 165 cells/μL is highly predictive of achieving MMR at 12 months.

Immune dysregulation in chronic inflammatory demyelinating polyneuropathy

ObjectiveChronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disorder of the peripheral nerves with an incompletely understood underlying pathophysiology. This investigation focused on defining B and T cell frequencies, T cell functional capacity and innate immune system analysis in patients with CIDP. MethodsBy using multi-parameter flow cytometry, we examined the phenotype and function of PBMCs in 25 CIDP patients who were relatively clinically stable on treatment who met EFNS/PNS criteria, 21 patients with genetically confirmed hereditary neuropathy and 25 healthy controls. We also evaluated the regulatory T cell (Treg) inhibitory capacity by co-culturing Treg and effector T cells. ResultsProinflammatory CD4 T cells, especially type 1 helper T cell (Th1) and CD8 T cells in patients with CIDP were found to have an enhanced capacity to produce inflammatory cytokines. There was no difference in frequency of Th17 regulatory cells in CIDP patients versus healthy controls, however, Treg function was impaired in CIDP patients. There was no remarkable difference in innate immune system measures. Within B cell subsets, transitional cell frequency was decreased in CIDP patients. InterpretationPatients with CIDP clinically stable on treatment continued to show evidence of a proinflammatory state with impaired Treg function. This potentially implies an inadequate suppression of ongoing inflammation not addressed by standard of care therapies as well as persistent activity of disease while on treatment. Targeting T cells, especially inhibiting Th1 and polyfunctional CD8 T cells or improving Treg cell function could be potential targets for future therapeutic research.

Minimal Residual Disease Status in Multiple Myeloma 1 Year After Autologous Hematopoietic Cell Transplantation and Lenalidomide Maintenance Are Associated With Long-Term Overall Survival.

Prognostic Immunophenotyping in Myeloma Response (PRIMeR) is an ancillary study of minimal residual disease (MRD) assessment for multiple myeloma by next-generation multiparameter flow cytometry (MFC). Patients were enrolled on a three-arm randomized control trial (Blood and Marrow Transplants Clinical Trials Network 0702 Stem Cell Transplant for Myeloma in Combination of Novel Agents [STaMINA]; ClinicalTrials.gov identifier: NCT01109004). Four hundred and thirty-five patients consented to the MRD panel, which included 10 monoclonal antibodies measured via six-color MFC. MRD was measured at baseline/preautologous hematopoietic cell transplant (BL/preAutoHCT), premaintenance (PM), and 1 year (Y1) after AutoHCT with a sensitivity of 10-5 to 10-6. The primary objective was to assess MRD-negative (MRDneg) at 1 year after AutoHCT and progression-free survival and overall survival (PFS/OS). Similar to the STaMINA results, at a median follow-up of 70 months, there was no significant difference in PFS/OS by treatment arm in the PRIMeR patients. MRDneg at all three time points was associated with significantly improved PFS, and MRDneg at Y1 had significantly longer OS. Multivariate analysis of PFS, adjusting for disease risk and treatment arm, demonstrated hazard ratios (HRs) in MRD-positive patients compared with MRDneg patients at BL, PM, and Y1 of 1.55 (P = .0074), 1.83 (P = .0007), and 3.61 (P < .0001), respectively. Corresponding HRs for OS were 1.19 (P = .48), 0.88 (P = .68), and 3.36 (P < .001). Patients with sustained MRDneg or who converted to MRDneg by Y1 had similar PFS/OS. To our knowledge, this first, prospective US cooperative group, multicenter study demonstrates that MRDneg at Y1 after AutoHCT with lenalidomide maintenance is prognostic for improved 6-year PFS and OS. Serial MRD measurements may direct trials to test how further therapy may improve long-term PFS and OS.

Survival after allogeneic transplantation according to pretransplant minimal residual disease and conditioning intensity in patients with acute myeloid leukemia.

The measurement of minimal residual disease (MRD) by multiparametric flow cytometry (MFC) before hematopoietic stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML) is a powerful prognostic factor. The interaction of pretransplant MRD and the conditioning intensity has not yet been clarified. The aim of this study is to analyze the transplant outcomes of patients with AML who underwent HSCT in complete remission (CR), comparing patients with positive MRD (MRD+) and negative MRD (MRD-) before HSCT, and the interaction between conditioning intensity and pre-HSCT MRD. We retrospectively analyzed the transplant outcomes of 118 patients with AML who underwent HSCT in CR in a single institution, comparing patients with MRD+ and MRD- before HSCT using a cutoff of 0.1% on MFC, and the interaction between conditioning intensity and pre-HSCT MRD. Patients with MRD+ before HSCT had a significantly worse 2-year (2y) event-free survival (EFS) (56.5% vs. 32.0%, p = 0.018) than MRD- patients, due to a higher cumulative incidence of relapse (CIR) at 2 years (49.0% vs. 18.0%, p = 0.002), with no differences in transplant-related mortality (TRM) (2y-TRM, 19.0% and 25.0%, respectively, p = 0.588). In the analysis stratified by conditioning intensity, in patients who received MAC, those with MRD- before HSCT had better EFS (p = 0.009) and overall survival (OS) (p = 0.070) due to lower CIR (p = 0.004) than MRD+ patients. On the other hand, the survival was similar in reduced intensity conditioning (RIC) patients regardless of the MRD status. Patients with MRD+ before HSCT have worse outcomes than MRD- patients. In patients who received MAC, MRD- patients have better EFS and OS due to lower CIR than MRD+ patients, probably because they represent a more chemo-sensitive group. However, among RIC patients, results were similar regardless of the MRD status.

Minimal residual disease monitoring in childhood Philadelphia chromosome-positive acute lymphoblastic leukemia: prognostic significance and correlation between multiparameter flow cytometry and real-time quantitative polymerase chain reaction

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Clinical Characteristics and Diagnosis of Ph-Positive Mixed Phenotype Acute Leukemia.

The goal was to improve the clinical cognition of Ph-positive mixed phenotype acute leukemia and avoid misdiagnosis or delayed diagnosis. The clinical manifestations and laboratory results (bone marrow cell morphology, multiparameter flow cytometry, and cytogenetics) of a case of Ph-positive mixed phenotype acute leukemia were analyzed, and related literature was reviewed. Blood routine: WBC 386.35 x 109/L, HGB 117.00 g/L, PLT 31 x 109/L; 80% of the original cells can be seen by artificial classification. Morphological examination of bone marrow cells showed that the proliferation of nucleated cells was obviously active, and the original cells accounted for 76%. The size of the original cells was somewhat uniform, most of the cells had less mass, were stained light grayish blue, the cytoplasm particles were not obvious, the nuclei were mostly round or quasi-round, some of them showed distortion and nuclear notch, and the chromatin was coarse. Some of the cells were rich in mass, small azurin granules were seen, the nuclei were regular, most of them were round, the chromatin was fine, the myeloperoxidase and esterase staining were negative, the eosinophils accounted for 2.5%, and the basophils accounted for 0.5%. Flow cytometry immunotyping: Two groups of abnormal cells were seen in the bone marrow. 1. A group included 12.32% of nuclear cells and showed abnormal myeloid primitive cell phenotype. Main expression: CD117, CD34, CD38, HLA-DR, CD33, CD64, CD123, weak expression: CD13, CD19. 2. The other group included 45.61% of the nuclear cells and had a B-lymphoblastic phenotype. Main expression: CD34, CD38, HLA-DR, CD123, CD19, CD10, CD9, cCD79a, TDT, weak expression of CD13, CD22. Mixed phenotype acute leukemia (M/B) immunophenotype was considered. Chromosome: 46,XY,t(9; 22)(q34;q11.2) [20]. BCR-ABL (P210) fusion gene was positive. Mixed phenotype acute leukemia (MPAL) is a rare type of malignant hematologic disease. Its diagnosis is based on the comprehensive evaluation of bone marrow cell morphology, immunophenotype, molecular and cytogenetic features.

Widespread alterations in systemic immune profile are linked to lung function heterogeneity and airway microbes in cystic fibrosis

BackgroundExcessive inflammation and recurrent airway infections characterize people with cystic fibrosis (pwCF), a disease with highly heterogeneous clinical outcomes. How the overall immune response is affected in pwCF, its relationships with the lung microbiome, and the source of clinical heterogeneity have not been fully elucidated. MethodsPeripheral blood and sputum samples were collected from 28 pwCF and an age-matched control group. Systemic immune cell subsets and surface markers were quantified using multiparameter flow cytometry. Lung microbiome composition was reconstructed using metatranscriptomics on sputum samples, and microbial taxa were correlated to circulating immune cells and surface markers expression. ResultsIn pwCF, we found a specific systemic immune profile characterized by widespread hyperactivation and altered frequencies of several subsets. These included substantial changes in B-cell subsets, enrichment of CD35+/CD49d+ neutrophils, and reduction in dendritic cells. Activation markers and checkpoint molecule expression levels differed from healthy subjects. CTLA-4 expression was increased in Tregs and, together with impaired B-cell subsets, correlated with patients' lung function. Concentrations and frequencies of key immune cells and marker expression correlated with the relative abundance of commensal and pathogenic bacteria in the lungs. ConclusionThe CF-specific immune signature, involving hyperactivation, immune dysregulation with alteration in Treg homeostasis, and impaired B-cell function, is a potential source of lung function heterogeneity. The activity of specific microbes contributes to disrupting the balance of the immune response. Our data provide a unique foundation for identifying novel markers and immunomodulatory targets to develop the future of cystic fibrosis treatment and management.

SIT1 identifies circulating hypoactive T cells with elevated cytotoxic molecule secretion in systemic lupus erythematosus patients.

This study aims to elucidate the expression and functionality of SIT1 in circulating CD8/CD4 + T cells in humans and to delineate its significance in systemic lupus erythematosus (SLE) patients. We employed multiparametric flow cytometry to investigate the expression of SIT1 in circulating CD8/CD4 + T cells and their respective subsets, comparing healthy controls (HCs) with SLE patients. Furthermore, we assessed the levels of granzyme B, perforin, IL-17, and IFN-γ in SIT1-related CD8/CD4 + T cells from both HCs and SLE patients, both before and after PMA stimulation. Clinically, we conducted receiver operating characteristic curve analysis and correlation analysis to evaluate the clinical relevance of SIT1-related CD8/CD4 + T cells in SLE patients. SIT1 exhibited higher expression in CD4 + T cells, with SIT1 - T cells demonstrating elevated levels of granzyme B, perforin, and IFN-γ compared to SIT1 + T cells. PMA-stimulated T cells exhibited reduced SIT1 expression compared to unstimulated T cells. SLE patients displayed increased SIT1 + proportions in CD8 + T cells and decreased SIT1 + CD4 + T cell numbers. Additionally, SIT1 + cells in SLE patients exhibited significantly higher levels of granzyme B and perforin compared to HCs. SIT1 + cells demonstrated significant associations with clinical indicators in SLE patients, with indicators related to SIT1 proving valuable in the diagnosis of SLE patients. SIT1 is inversely correlated with T cell activation. In SLE patients, SIT1 expression is altered in T cells concomitant with an augmented secretion of cytotoxic molecules. This upregulation may contribute to the pathogenesis of SLE and enhance its diagnostic potential.

Measurable residual disease monitoring by ddPCR in the early posttransplant period complements the traditional MFC method to predict relapse after HSCT in AML/MDS: a multicenter retrospective study

BackgroundDroplet digital PCR (ddPCR) is widely applied to monitor measurable residual disease (MRD). However, there are limited studies on the feasibility of ddPCR-MRD monitoring after allogeneic hematopoietic stem cell transplantation (allo-HSCT), especially targeting multiple molecular markers simultaneously.MethodsOur study collected samples from patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS) in complete remission after allo-HSCT between January 2018 and August 2021 to evaluate whether posttransplant ddPCR-MRD monitoring can identify patients at high risk of relapse.ResultsOf 152 patients, 58 (38.2%) were MRD positive by ddPCR within 4 months posttransplant, with a median variant allele frequency of 0.198%. The detectable DTA mutations (DNMT3A, TET2, and ASXL1 mutations) after allo-HSCT were not associated with an increased risk of relapse. After excluding DTA mutations, patients with ddPCR-MRD positivity had a significantly higher cumulative incidence of relapse (CIR, 38.7% vs. 9.7%, P < 0.001) and lower rates of relapse-free survival (RFS, 55.5% vs. 83.7%, P < 0.001) and overall survival (OS, 60.5% vs. 90.5%, P < 0.001). In multivariate analysis, ddPCR-MRD positivity of non-DTA genes was an independent adverse predictor for CIR (hazard ratio [HR], 4.02; P < 0.001), RFS (HR, 2.92; P = 0.002) and OS (HR, 3.12; P = 0.007). Moreover, the combination of ddPCR with multiparameter flow cytometry (MFC) can further accurately identify patients at high risk of relapse (F+/M+, HR, 22.44; P < 0.001, F+/M-, HR, 12.46; P < 0.001 and F-/M+, HR, 4.51; P = 0.003).ConclusionddPCR-MRD is a feasible approach to predict relapse after allo-HSCT in AML/MDS patients with non-DTA genes and is more accurate when combined with MFC.Trial registrationClinicalTrials.gov identifier: NCT06000306. Registered 17 August 2023 –Retrospectively registered (https://clinicaltrials.gov/study/NCT06000306?term=NCT06000306&rank=1).

The Dysregulation of the Monocyte-Dendritic Cell Interplay Is Associated with In-Hospital Mortality in COVID-19 Pneumonia.

Background: The monocyte-phagocyte system (MPS), including monocytes/macrophages and dendritic cells (DCs), plays a key role in anti-viral immunity. We aimed to analyze the prognostic value of the MPS components on in-hospital mortality in a cohort of 58 patients (M/F; mean age ± SD years) with COVID-19 pneumonia and 22 age- and sex-matched healthy controls. Methods: We measured frequencies and absolute numbers of peripheral blood CD169+ monocytes, conventional CD1c+ and CD141+ (namely cDC2 and cDC1), and plasmacytoid CD303+ DCs by means of multi-parametric flow cytometry. A gene profile analysis of 770 immune-inflammatory-related human genes and 20 SARS-CoV-2 genes was also performed. Results: Median frequencies and absolute counts of CD169-expressing monocytes were significantly higher in COVID-19 patients than in controls (p 0.04 and p 0.01, respectively). Conversely, percentages and absolute numbers of all DC subsets were markedly depleted in patients (p < 0.0001). COVID-19 cases with absolute counts of CD169+ monocytes above the median value of 114.68/μL had significantly higher in-hospital mortality (HR 4.96; 95% CI: 1.42-17.27; p = 0.02). Interleukin (IL)-6 concentrations were significantly increased in COVID-19 patients (p < 0.0001 vs. controls), and negatively correlated with the absolute counts of circulating CD1c+ cDC2 (r = -0.29, p = 0.034) and CD303+ pDC (r = -0.29, p = 0.036) subsets. Viral genes were upregulated in patients with worse outcomes along with inflammatory mediators such as interleukin (IL)-1 beta, tumor necrosis-α (TNF-α) and the anticoagulant protein (PROS1). Conversely, surviving patients had upregulated genes related to inflammatory and anti-viral-related pathways along with the T cell membrane molecule CD4. Conclusions: Our results suggest that the dysregulated interplay between the different components of the MPS along with the imbalance between viral gene expression and host anti-viral immunity negatively impacts COVID-19 outcomes. Although the clinical scenario of COVID-19 has changed over time, a deepening of its pathogenesis remains a priority in clinical and experimental research.

Human T-Cell Responses to Metallic Ion-Doped Bioactive Glasses.

Biomaterials are extensively used as replacements for damaged tissue with bioactive glasses standing out as bone substitutes for their intrinsic osteogenic properties. However, biomaterial implantation has the following risks: the development of implant-associated infections and adverse immune responses. Thus, incorporating metallic ions with known antimicrobial properties can prevent infection, but should also modulate the immune response. Therefore, we selected silver, copper and tellurium as doping for bioactive glasses and evaluated the immunophenotype and cytokine profile of human T-cells cultured on top of these discs. Results showed that silver significantly decreased cell viability, copper increased the T helper (Th)-1 cell percentage while decreasing that of Th17, while tellurium did not affect either cell viability or immune response, as evaluated via multiparametric flow cytometry. Multiplex cytokines assay showed that IL-5 levels were decreased in the copper-doped discs, compared with its undoped control, while IL-10 tended to be lower in the doped glass, compared with the control (plastic) while undoped condition showed lower expression of IL-13 and increased MCP-1 and MIP-1β secretion. Overall, we hypothesized that the Th1/Th17 shift, and specific cytokine expression indicated that T-cells might cross-activate other cell types, potentially macrophages and eosinophils, in response to the scaffolds.

Early recovery of natural killer cells post T-cell depleted allogeneic stem cell transplantation using alemtuzumab “in the bag”

BackgroundAllogeneic stem cell transplantation (SCT) is a critical therapy for haematological malignancy but may lead to acute and chronic graft versus host disease (GvHD). T-cell depletion with alemtuzumab, either in vivo or ex vivo, reduces the incidence of GvHD but is a risk factor for disease relapse and poor immune reconstitution. Natural killer (NK) cells are the first lymphocytes to recover. Classical NK cells make up >90% of the normal circulating population and can directly kill neoplastic or virally infected cells while the regulatory subset makes up <10%, secretes cytokines and is not cytotoxic. The recovery and balance of these subsets post SCT remains controversial, with most studies analysing patients who received unmanipulated grafts and in vivo immunosuppression. ObjectiveThe aim was to assess the early recovery of NK cells in 18 consecutive patients receiving ex vivo T-cell depleted SCT and to compare the results to 25 individuals receiving haploidentical non-T cell depleted grafts. MethodsAll patients received myeloablative conditioning. After stem cell collection, the stem cells of the T cell depleted group were treated “in the bag” with alemtuzumab (CAMPATH 1H) at a concentration of 1mg/108 mononuclear cells and thereafter immediately infused. For those receiving non-T cell depleted grafts, GvHD prophylaxis was with post infusion therapeutic doses of cyclophosphamide. Blood samples were collected at days 21, 28 and 90. Complete blood counts were performed on an automated analyser while lymphocyte and NK subsets were examined using multiparameter flowcytometry. NK cells were defined as lymphocytes which were CD3-/CD56+. The classical subset was recognised as CD56dim/CD16+ while the regulatory population as CD56bright/CD16-. The results for both transplant types were compared at all time points using SPSS v8 statistical software. ResultsThe recovery of lymphocytes was slow in both groups. Those receiving non-T cell depleted grafts had significantly higher T cell counts at day 21 and 28 when compared to the T cell depleted group (P < 0.05). In contrast, NK cells in the ex vivo T-cell depleted patients recovered rapidly and by day 21 was no different to normal (p > 0.05), while the non-T cell depleted group had significantly decreased numbers (p < 0.001), only recovering at day 90. Both groups had abnormal NK cell subset ratios with significantly elevated percentages of regulatory cells (p < 0.05). However, significant differences were observed between the two groups with those receiving T cell depleted grafts having lower percentages of regulatory cells as well as higher numbers of classical NK cells at day 21 and 28 (p < 0.01). ConclusionThis study of ex vivo T-cell depleted SCT's demonstrates that NK cells recover quicker when compared to those receiving unfractionated grafts. These results may have implications for GvHD and the GvL effect which warrants further study.

Early dynamic changes to monocytes following major surgery are associated with subsequent infections.

Post-operative infections are a common cause of morbidity following major surgery. Little is understood about how major surgery perturbs immune function leading to heightened risk of subsequent infection. Through analysis of paired blood samples obtained immediately before and 24 h following surgery, we evaluated changes in circulating immune cell phenotype and function across the first 24 h, to identify early immune changes associated with subsequent infection. We conducted a prospective observational study of adult patients undergoing major elective gastrointestinal, gynecological, or maxillofacial surgery requiring planned admission to the post-anesthetic care unit. Patients were followed up to hospital discharge or death. Outcome data collected included mortality, length of stay, unplanned intensive care unit admission, and post-operative infections (using the standardized endpoints in perioperative medicine-core outcome measures for perioperative and anesthetic care criteria). Peripheral blood mononuclear cells were isolated prior to and 24 h following surgery from which cellular immune traits including activation and functional status were assessed by multi-parameter flow cytometry and serum immune analytes compared by enzyme-linked immunosorbent assay (ELISA). Forty-eight patients were recruited, 26 (54%) of whom developed a post-operative infection. We observed reduced baseline pre- and post-operative monocyte CXCR4 and CD80 expression (chemokine receptors and co-stimulation markers, respectively) in patients who subsequently developed an infection as well as a profound and selective post-operative increase in CD4+ lymphocyte IL-7 receptor expression in the infection group only. Higher post-operative monocyte count was significantly associated with the development of post-operative infection (false discovery rate < 1%; adjusted p-value = 0.001) with an area under the receiver operating characteristic curve of 0.84 (p < 0.0001). Lower monocyte chemotaxis markers, higher post-operative circulating monocyte counts, and reduced co-stimulatory signals are associated with subsequent post-operative infections. Identifying the underlying mechanisms and therapeutics to reverse defects in immune cell function requires further exploration.

Loss of hematopoietic progenitors heterogeneity is an adverse prognostic factor in lower-risk myelodysplastic neoplasms

Myelodysplastic neoplasms (MDS) are characterized by clonal evolution starting from the compartment of hematopoietic stem and progenitors cells (HSPCs), leading in some cases to leukemic transformation. We hypothesized that deciphering the diversity of the HSPCs compartment may allow for the early detection of an emergent sub-clone that drives disease progression. Deep analysis of HSPCs repartition by multiparametric flow cytometry revealed a strong disorder of the hematopoietic branching system in most patients at diagnosis with different phenotypic signatures closely related to specific MDS features. In two independent cohorts of 131 and 584 MDS, the HSPCs heterogeneity quantified through entropy calculation was decreased in 47% and 46% of cases, reflecting a more advanced state of the disease with deeper cytopenias, higher IPSS-R risk and accumulation of somatic mutations. We demonstrated that patients with lower-risk MDS and low CD34 + CD38+HSPCs entropy had an adverse outcome and that this parameter is as an independent predictive biomarker for progression free survival, leukemia free survival and overall survival. Analysis of HSPCs repartition at diagnosis represents therefore a very powerful tool to identify lower-risk MDS patients with a worse outcome and valuable for clinical decision-making, which could be fully integrated in the MDS diagnostic workflow.

Water‐Soluble Fluorescent Polymer Dyes with Tunable Emission Spectra for Flow Cytometry Applications

AbstractThe application of spectrally unique, bright, and water‐soluble fluorescent dyes is indispensable for the analysis of biological systems. Multiparameter flow cytometry is a powerful tool for characterization of mixed cell populations. To discriminate the different cell populations, they are typically stained by a set of fluorescent reagents, e.g., antibody‐fluorophore conjugates. The number of parameters which can be studied simultaneously strongly depends on the availability of reagents which can be differentiated by their spectral properties. In this study a series of fluorescent polymer dyes was developed, that can be excited with a single violet laser (405 nm) but distinguished by their unique emission spectra. The polyfluorene‐based polymers can be used on their own, or in combination with covalently bound small‐molecule dyes to generate energy transfer constructs to red‐shift the emission wavelength based on Förster resonance energy transfer (FRET). The polymer dyes were utilized in a biological flow cytometry assay by conjugating several of them to antibodies, demonstrating their effectiveness as reagents. This report represents the first systematic investigation of structure–property relationships for this type of fluorescent dyes.