Multiparameter Flow Cytometry Analysis Research Articles

Ocena minimalnej choroby resztkowej w szpiczaku plazmocytowym

Minimalną chorobę resztkową (MRD) u pacjenta z rozpoznaniem szpiczaka plazmocytowego defi-niuje się jako populację nowotworowych komórek plazmatycznych, która pozostała w organizmie chorego po osiągnięciu odpowiedzi całkowitej (CR). Ostatecznym celem badań MRD jest dążenie do identyfikacji chorych o odmiennym rokowaniu i indywidualizacji leczenia na tej podstawie. Ocenę MRD u chorych na szpiczaka plazmocytowego zaleca się u młodszych pacjentów, którzy osiągną CR po przeszczepieniu autologicznych krwiotwórczych komórek macierzystych oraz u chorych starszych osiągających CR po chemioterapii opartej na inhibitorach proteasomu. Powinno się oznaczać MRD wyłącznie w szpiku kostnym. Do rekomendowanych metod oceny MRD w szpiczaku plazmocytowym zalicza się sekwencjonowanie następnej generacji genów immunoglobulinowych oraz wieloparametryczną cytometrię przepływową, przy czym wybór jednej z tych metod powinien zależeć od doświadczenia danego ośrodka oraz możliwości wykonania badania cytometrycznego w czasie 24 godzin od pobrania próbki szpiku. Eradykację MRD powinna się obecnie uważać za istotny cel terapii szpiczaka plazmocytowego. Jednak, ze względu na brak wystarczających danych do podejmowania decyzji klinicznych wyłącznie na podstawie wyniku badania MRD, istnieje po¬trzeba dalszych, dobrze zaprojektowanych badań klinicznych w tym zakresie.

An activated Th17-prone T cell subset involved in chronic graft-versus-host disease sensitive to pharmacological inhibition.

Chronic graft-versus-host disease (cGvHD) remains a major complication of allogeneic stem cell transplantation requiring novel therapies. CD146 and CCR5 are expressed by activated T cells and associated with increased T cell migration capacity and Th17 polarization. We performed a multiparametric flow cytometry analysis in a cohort of 40 HSCT patients together with a cGvHD murine model to understand the role of CD146-expressing subsets. We observed an increased frequency of CD146+ CD4 T cells in the 20 patients with active cGvHD with enhanced RORγt expression. This Th17-prone subset was enriched for cells coexpressing CD146 and CCR5 that harbor mixed Th1/Th17 features and were more frequent in cGvHD patients. Utilizing a murine cGvHD model with bronchiolitis obliterans (BO), we observed that donor T cells from CD146-deficient mice versus those from WT mice caused significantly reduced pulmonary cGvHD. Reduced cGvHD was not the result of failed germinal center B cell or T follicular helper cell generation. Instead, CD146-deficient T cells had significantly lower pulmonary macrophage infiltration and T cell CCR5, IL-17, and IFN-γ coexpression, suggesting defective pulmonary end-organ effector mechanisms. We, thus, evaluated the effect of TMP778, a small-molecule RORγt activity inhibitor. TMP778 markedly alleviated cGvHD in murine models similarly to agents targeting the Th17 pathway, such as STAT3 inhibitor or IL-17-blocking antibody. Our data suggest CD146-expressing T cells as a cGvHD biomarker and suggest that targeting the Th17 pathway may represent a promising therapy for cGvHD.

The Effect of Antiretroviral Naïve HIV-1 Infection on the Ability of Natural Killer Cells to Produce IFN-γ upon Exposure to Plasmodium falciparum-Infected Erythrocytes

Background: In sub-Saharan Africa, intense perennial Plasmodium species transmission coincides with areas of high prevalence of the human immunodeficiency virus type 1 (HIV) infection. This implies that antiretroviral naïve HIV-infected people living within these regions are repeatedly exposed to Plasmodium species infection and consequently malaria. Natural killer (NK) cells are known to contribute to malaria immunity through the production of IFN-γ after exposure to Plasmodium falciparum-infected erythrocytes (infected red blood cells [iRBC]). However, in antiretroviral naïve HIV-1 infection, these functions could be impaired. In this study we assess the ability of NK cells from antiretroviral naïve HIV-1-infected people to respond to iRBC. Method: Magnetically sorted NK cells from antiretroviral naïve HIV-1-infected people were tested for their ability to respond to iRBC following in vitro coculture. NK cell IFN-γ production after coculture was measured through multiparametric flow cytometry analysis. Results: Our data show a significant reduction (p = 0.03) in IFN-γ production by NK cells from antiretroviral naïve HIV-1-infected people after coculture with iRBCs. This was in contrast to the NK cell response from healthy controls, which demonstrated elevated IFN-γ production. NK cell IFN-γ production from untreated HIV-1-infected participants correlated inversely with the viral load (r = -0.5, p = 0.02) and positively with total helper CD4⁺ T-cell count (r = 0.4, p = 0.04). Thus, antiretroviral naïve HIV-1 infection can dampen NK cell-mediated immunity to P. falciparum infection in malaria-intense regions. This could in effect escalate morbidity and mortality in people chronically infected with HIV-1.

Defining an inflamed tumor immunophenotype in recurrent, metastatic squamous cell carcinoma of the head and neck

ObjectivesImmune checkpoint inhibitors have demonstrated clinical benefit in recurrent, metastatic (R/M) squamous cell carcinoma of the head and neck (SSCHN), but lacking are biomarkers that predict response. We sought to define an inflamed tumor immunophenotype in this R/M SCCHN population and correlate immune metrics with clinical parameters and survival. MethodsTumor samples were prospectively acquired from 34 patients to perform multiparametric flow cytometry and multidimensional clustering analysis integrated with next-generation sequencing data, clinical parameters and outcomes. ResultsWe identified an inflamed subgroup of tumors with prominent CD8+ T cell infiltrates and high PD-1/TIM3 co-expression independent of clinical variables, with improved survival compared with a non-inflamed subgroup (median overall survival 84.0 vs. 13.0months, p=0.004). The non-inflamed subgroup demonstrated low CD8+ T cells, low PD-1/TIM3 co-expression, and higher Tregs. Overall non-synonymous mutational burden did not correlate with response to PD-1 blockade in a subset of patients. ConclusionR/M SCCHN patients with an inflamed tumor immunophenotype demonstrate improved survival. Further prospective studies are needed to validate these findings and explore the use of immunophenotype to guide patient selection for immunotherapeutic approaches.

Real Time Immunophenotyping of Leukocyte Subsets Early after Double Cord Blood Transplantation Predicts Graft Function

Cord blood transplantation (CBT) recipients are at increased risk for delayed engraftment and primary graft failure, complications that are often indistinguishable early post-transplantation. Current assays fail to accurately identify recipients with slow hematopoietic recovery and distinguish them from those with pending graft failure. To address this, we prospectively examined the kinetics of immune cell subset recovery in the peripheral blood of 39 patients on days +7 and +14 after double-unit CBT (dCBT) by multiparametric flow cytometry analysis, which we term real-time immunophenotyping (RTIP). RTIP analysis at day +14 revealed distinctive patterns of reconstitution and, importantly, identified patients with slow hematopoietic recovery who went on to engraft. Strikingly, higher absolute numbers of circulating monocytes and natural killer cells at day +14 were predictive of engraftment, but only the absolute number of circulating monocytes was significantly correlated with time to engraftment. This is the first evidence that RTIP on patient peripheral blood mononuclear cells early after dCBT is technically feasible and can be used as a “signature” for predicting the kinetics of hematopoietic recovery. Furthermore, RTIP is a time- and cost-efficient methodology that has the potential to become a clinically feasible diagnostic tool to guide therapeutic interventions in high-risk patients; therefore, its utility should be evaluated in a large cohort of patients.

NKG2A-Expressing Natural Killer Cells Dominate the Response to Autologous Lymphoblastoid Cells Infected with Epstein-Barr Virus.

Epstein–Barr virus (EBV) is a human γ-herpesvirus that establishes latency and lifelong infection in host B cells while achieving a balance with the host immune response. When the immune system is perturbed through immunosuppression or immunodeficiency, however, these latently infected B cells can give rise to aggressive B cell lymphomas. Natural killer (NK) cells are regarded as critical in the early immune response to viral infection, but their role in controlling expansion of infected B cells is not understood. Here, we report that NK cells from healthy human donors display increased killing of autologous B lymphoblastoid cell lines (LCLs) harboring latent EBV compared to primary B cells. Coculture of NK cells with autologous EBV+ LCL identifies an NK cell population that produces IFNγ and mobilizes the cytotoxic granule protein CD107a. Multi-parameter flow cytometry and Boolean analysis reveal that these functional cells are enriched for expression of the NK cell receptor NKG2A. Further, NKG2A+ NK cells more efficiently lyse autologous LCL than do NKG2A− NK cells. More specifically, NKG2A+2B4+CD16−CD57−NKG2C−NKG2D+ cells constitute the predominant NK cell population that responds to latently infected autologous EBV+ B cells. Thus, a subset of NK cells is enhanced for the ability to recognize and eliminate autologous, EBV-infected transformed cells, laying the groundwork for harnessing this subset for therapeutic use in EBV+ malignancies.

Novel Flow Cytometry-Based Biomarkers Predict Recurrence in Myeloma Patients through Detection of MRD in the Bone Marrow and CTCs in Peripheral Blood

Introduction: The presence of a minimal residual disease (MRD) that remains after treatment is one of the main reasons for recurrence and relapse in multiple myeloma (MM) patients. Diagnosis of MRD is becoming vital to assess the effectiveness of the treatment as well as to predict survival among patients with complete remission. CD138 (syndecan-1) is the gold standard marker for detecting MM cells using multiparametric flow cytometry analysis or immunohistochemistry (IHC) staining of BM biopsies. However, the presence of highly clonogenic, drug resistant and stem-cell like CD138-negative MM cells have been previously demonstrated. Moreover, hypoxia which is known to drive MM progression, drug resistance and metastasis was shown to significantly decrease CD138 expression in MM cells. In this study, we utilized a novel set of biomarkers to detect MRD in the bone marrow as well as circulating tumor cells (CTCs) in the blood, in order to predict progression free survival (PFS) in MM patients defined as complete remission according to the detection of CD138+ cells in their bone marrow.Methods: To detect myeloma cells, we utilized a novel set of biomarkers, independent of CD138 expression and hypoxic state of MM cells (CD38+/CD3-/CD19-/CD14-/CD16-/CD123-) by two-color flow cytometry. We detected MM cells in the bone marrow of 25 patients with complete remission and very good partial response, whose bone marrow was defined as a CD138-negative (less than 0.5%). In order to retrospectively correlate the involvement of MM cells (%) with PFS, we used 24 months as a cut-off and compared the results acquired with the new method to traditional CD138-based flow or histology. In addition, based on the percentage of detected MM cells with the 2% cut-off, we analyzed the time to progression (months). Moreover, we detected MM cells in the peripheral blood from matching MM patients and performed analogous analysis. Furthermore, we also detected CTCs in 7 newly diagnosed patients and compared to 7 patients with progressive disease.Results: A study conducted on 25 patients with their bone marrow defined as a CD138-negative (less than 0.5%) showed that the novel strategy to detect MM cells was more precise than CD138-based flow or histology in predicting PFS. Patients who relapsed in less than 24 months had an average (±SEM) of 3.53±0.82%, while patients who relapsed later than 24 months had an average of 1.15±0.27% MM cells in the bone marrow when detected by the new method (p=0.004). In addition, the median PFS with <2% or ≥2% of MM cells detected by novel strategy was 31.6±2.8 and 18.5±2.2 months, respectively (p=0.004). Similarly, while CD138 detected very low amounts of CTCs and demonstrated no difference between fast and slow relapsing patients; we found that the new biomarkers detected significant differences in the number of circulating MM cells in patients who relapsed fast and patients who relapsed late or did not relapse. Patients who relapsed in less than 24 months had 1.74±0.42%, while patients who relapsed later than 24 months had 0.4±0.08% CTCs in the peripheral blood (p=0.01). In addition, we detected significantly more CTCs in patients with progressive disease (1.27±0.24%) compared to newly diagnosed MM patients (0.63±0.12%), respectively (p=0.03).Conclusions: The novel flow cytometry-based set of biomarkers provides an alternative strategy to detect MRD in the bone marrow and CTCs in the peripheral blood of MM patients, and both allowed prediction of PFS in MM patients. DisclosuresDe La Puente:Cellatrix LLC: Other: Co-founder. Vij:Amgen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Janssen: Consultancy; Jazz: Consultancy; Shire: Consultancy; Karyopharma: Consultancy; Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy. Azab:Targeted Therapeutics LLC: Other: Founder and owner; Cleave Bioscience: Research Funding; Verastem: Research Funding; Cell Works: Research Funding; Karyopharm: Research Funding; Vasculox: Research Funding; Glycomimetics: Research Funding; Cellatrix LLC: Other: Founder and owner; Selexys: Research Funding.

Extracellular Vesicles Play an Important Role in Intercellular Communication Between Bone Marrow Stroma and Hematopoietic Progenitor Cells in Myeloproliferative Neoplasms

The complex interplay between bone marrow-derived mesenchymal stromal cells (BM-MSC) and neoplastic hematopoietic cells is involved in the progression of myeloproliferative neoplastic (MPN) diseases. Extracellular vesicles (EV) have emerged as a complex cell-to-cell communication system within the neoplastic microenvironment. EV are able to reprogram recipient cells by transferring proteins, mRNA and microRNA from their cell of origin. We aimed to analyze the microRNA content of EV obtained from MPN BM-MSC, as well as the changes induced when these EV are incorporated into hematopoietic progenitor cells (HPC).EV were isolated from BM-MSC of MPN patients (n=22) and healthy donors (HD) (n=19) by ultracentrifugation. Characterization of EV by transmission electron microscopy (TEM), immunoblot, multiparametric flow cytometry (MFC) and NanoSight analysis revealed vesicles with a typical bilayer-membrane characteristic morphology with a size inferior to 500 nm, which were positive for various EV markers as CD63 and CD81, and for MSC markers as CD73, CD90 and CD44 (Figure 1). MicroRNA profiling by 384-well microfluidic cards (TaqMan® MicroRNA Array A) showed an overall increase in the microRNA expression in the MPN-MSC-derived EV, when compared to EV from donor MSC. Using RT-PCR, we observed that miR-155 was selectively enriched in EV released by MPN-MSC. An overexpression of this microRNA was observed in EV (p=0.032), while a downregulation was observed in BM-MSC (p=0.0078) (Figure 2).EV incorporation was demonstrated by fluorescence microscopy and MFC, where HPC (CD34+ cells obtained by immunomagnetic selection) were co-cultured with Vybrant Dil-labeled EV. For functional studies apoptosis and clonogenic assays (CFU-GM) were performed. We observed an increase in CD34+ cell viability after incorporating EV from BM-MSC (HD and MPN). Moreover, an increase (p=0.04) in miR-155 expression was observed when HD HPC incorporated EV from MPN-MSC. When neoplastic CD34+ cells incorporated the EV derived from MPN-MSC an increase of CFU-GM number was also observed.We suggest that EV released from MPN-MSC represent a mechanism of intercellular communication between malignant stromal and hematopoietic cells, through the transfer of genetic information that may be relevant in the pathophysiology of these diseases.Funding: GRS 1034/A/14 (C. Sanidad, JCYL) and FCT (SFRH/BD/86451/2012) [Display omitted] [Display omitted] DisclosuresSánchez-Guijo:Bristol-Myers-Squib: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Incyte: Consultancy, Honoraria. Del Cañizo:Celgene: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Jansen-Cilag: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Arry: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Alloresponses of Human T-Cells from Adult Peripheral Blood and Umbilical Cord Blood Are Differentially Impacted By Lenalidomide

Immunomodulatory drugs (IMiDs), such as lenalidomide provide a tool to enhance both direct anti-tumor and graft-versus-tumor effects after allogeneic haematopoietic stem-cell transplantation (AHCT). However, early clinical experience with IMiDs after AHCT using adult peripheral blood (APB) as a stem cell source has been limited by induction of graft-versus-host disease. Characterization of the mechanisms by which IMIDs can modulate alloresponses of T-cells and identification of differential effects on T-cells from disparate cell sources could facilitate more effective use of these drugs in the setting of AHCT. We therefore used in vitro modelling, multi-parameter flow cytometry and gene expression analysis to delineate the impact of the widely used IMiD lenalidomide on quantitative and qualitative alloresponses mediated by T-cells derived from APB and umbilical cord blood (UCB).We co-cultured carboxyfluorescein diacetate succinimidyl ester (CFSE)-labelled peripheral blood mononuclear cells (PBMC) from healthy adult donors or donated UCB units with irradiated allogeneic PBMC in the presence of 1μM lenalidomide or vehicle control. In this model, cellular and supernatant concentrations of lenalidomide (determined by mass spectrometry) were similar to in vivo levels achieved at doses used as maintenance after AHSCT in published studies. Functional alloresponses were quantified after 7-9 days of allogeneic co-culture by flow cytometry. In addition, co-culture responders were flow-sorted into alloproliferative or non-proliferative fractions and extracted RNA used for gene expression profiling.We demonstrate that lenalidomide potentiates net alloproliferation of APB derived T-cells cells by selectively enhancing allospecific proliferation of CD8+ T-cells (median 58% (lenalidomide-treated) versus 43% (untreated), n=40, p<0.001). Although pre-treatment of allogeneic stimulators and responders had a modest potentiating effect, lenalidomide was required during allogeneic co-culture for maximal potentiation of CD8+ alloresponses of APB T-cells. CD8+ T-cells had enhanced effector memory differentiation, were enriched for polyfunctional effectors (capable of producing two or more pro-inflammatory cytokines (IFN-γ, TNF-α, and IL-2) and/or expressing the lysosomal membrane-associated protein CD107a), and had a distinct gene expression profile with altered expression of key immunoregulatory genes and depletion of cellular ikaros levels.In common with our findings in APB T-cells, lenalidomide also potentiated proliferation of alloreactive CD8+ T-cells from UCB (median 43% (lenalidomide-treated) vs 24% (untreated), n=17, p=0.0005) with similar polyfunctional effector memory differentiation, immunoregulatory gene expression changes and cellular ikaros depletion. Importantly, lenalidomide reduced allospecific proliferation of UCB CD4+ T-cells (median 58% (untreated) versus 41% (lenalidomide-treated), n=17, p<0.01) whereas alloproliferation of APB CD4+ T-cells was unaffected. The reduction in UCB CD4+ alloproliferation was accompanied by selectively expansion of CD4+CD25+FOXP3+ regulatory T-cells (median 7.6% (lenalidomide-treated) vs 5.2% (untreated), n=12, p 0.02), resulting in an overall reduction in net UCB T-cell alloproliferation after lenalidomide treatment.Our findings show that lenalidomide has a qualitatively different impact on alloresponses of T-cells from different cell sources; alloresponses of APB T-cells are increased by lenalidomide via selective expansion of polyfunctional CD8+ effectors while lenalidomide limits alloresponses of UCB T-cells by reducing CD4+ effector expansion and increasing tolerogenic Treg. These findings have important implications for the future use of IMiDs in the setting of AHCT. DisclosuresNo relevant conflicts of interest to declare.

Minimal Residual Disease (MRD) Assessment By Multiparametric Flow Cytometry Is Prognostic for Progression-Free Survival in Phase 1/1b Relapsed/Refractory Acute Myeloid Leukemia (AML) Patients Treated with Idasanutlin MDM2 Antagonist

Introduction. Despite considerable efforts towards novel therapeutics research and discovery, outcomes in AML remain poor. Although composite Complete Remission (cCR; CR, CRp, CRi) is routinely used as a measure of therapeutic clinical activity, cCR frequently does not translate to survival benefit. On this basis, the characterization and tracking of minimal residual disease (MRD) has emerged as a tool to help better define the depth of such cCR to offer prognostic utility on AML patients likely to experience survival benefit from a given experimental therapeutic.The MDM2 antagonist idasanutlin has shown promising clinical activity in AML. Idasanutlin enhances p53 activity through antagonism of the MDM2:p53 interaction. Disruption of this protein:protein interaction inhibits MDM2 targeting of p53 for ubiquitination and degradation, thus stabilizing p53 protein to exert tumor suppressor transcriptional regulation and induction of apoptotic pathways.Patients and Methods. Trial NP28679 (NCT01773408) is a Phase 1/1b study evaluating idasanutlin as monotherapy or in combination with cytarabine in relapsed or refractory AML patients with safety as primary and complete remission as secondary endpoints, respectively (Martinelli, EHA, 2016.) Duration of response was available as exploratory clinical data for a subset of patient. Patients' pre-treatment bone marrow aspirate specimens were evaluated by multiparametric flow cytometry using an 18 marker surface antigen-based panel. MRD assessment occurred per protocol recommendation at the time of hematological malignancy response assessment (HMRA) at Day 28 and for those patients initially experiencing cCR at each subsequent HMRA. Further flow cytometry analyses were conducted for expression changes of known p53 regulated proteins in CD45+(dim) blasts correlating with drug exposure, consistent with mechanistic engagement.Results. PFS analyses for cCR patients versus non-CR Kaplan-Meier plots indicate the median for responders is 315d (95%CI: 282, NA) versus non-responders is 43.5d (95%CI: 30, NA). When MRD<1% versus >1% is applied as a cut-point, analytics show a statistical association with median PFS (log-rank p-value < .001) at 367d (95%CI: 219, NA) for <1%MRD versus >1% is 84d (95%CI: 30, NA.) Median MRD values for CR/CRp/CRi vs PR/HI vs PD are 0.42%, 1.79%, and 19.16%, respectively, again consistent with MRD serving as a surrogate for clinical activity (log rank test for trend p-value = .001) Additionally, multiparametric flow cytometry analysis of idasanutlin pharmacodynamic (PD) protein expression changes comparing pretreatment patient blood specimens to 24 hours following first dose administration indicates that increases in both p53 and MDM2 in CD45+(dim) blasts is associated with steady state drug exposure levels ([Spearman’s Correlation =0.27; p=.013] and [Spearman’s Correlation=0.24; p=.026,] respectively.) Interestingly, these changes in protein expression for p53 and MDM2 are associated with orthologous PD changes in serum protein macrophage inhibitory cytokine 1 (MIC-1) ([Spearman’s Correlation=0.23; p=.035] and [Spearman’s Correlation=0.22; p=.042,] respectively.) These PD changes are mechanistically consistent with enhanced p53 resulting from diminished MDM2 ubiquitination and degradation of p53.Conclusions. In summary, the results presented here are consistent with multiparametric flow cytometry MRD assessment as an early indication aligning with cCR in relapsed/refractory AML patients treated with idasanutlin. Further, assessment for association with progression-free survival indicates that the lowest quartile patients by MRD flow cytometry measurement (<1%) are likely to exhibit a pronounced survival benefit over those patients with higher detectable levels of MRD (>1%). As such, the data presented here support inclusion of MRD assessment by flow cytometry as a prognostic indicator to provide guiding information for assignment of depth of AML patient response. We will continue to monitor this biomarker for diagnostic potential as a prognostic indicator of survival-based outcomes in future randomized clinical studies of idasanutlin. DisclosuresLanza:Roche-Genentech: Employment. Martinelli:Pfizer: Consultancy, Speakers Bureau; MSD: Consultancy; Novartis: Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Genentech: Consultancy; Celgene: Consultancy, Speakers Bureau; Ariad: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; BMS: Speakers Bureau. Yee:Novartis Canada: Membership on an entity's Board of Directors or advisory committees, Research Funding. Jukofsky:Roche Pharma: Employment. Reis:Roche Pharma: Employment. Blotner:Roche Pharma: Employment. Drummond:Pfizer: Honoraria, Speakers Bureau; celgene: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Speakers Bureau; Roche: Honoraria, Speakers Bureau. Vey:Sunesis: Honoraria. Dickinson:GlaxoSmithKline: Consultancy, Research Funding. Kelly:Novartis: Consultancy, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Speakers Bureau. Theron:Roche Pharma: Employment. Venstrom:Roche-Genentech: Employment. Middleton:Roche Pharma: Employment. Chen:Roche Pharma: Employment. Kinnersley:Roche-Genentech: Employment, Equity Ownership. Nichols:Roche Pharma: Employment. Pierceall:Roche Pharma: Employment.

Minimal residual disease after transplantation or lenalidomide-based consolidation in myeloma patients: a prospective analysis.

We analyzed 50 patients who achieved at least a very good partial response in the RV-MM-EMN-441 study. Patients received consolidation with autologous stem-cell transplantation (ASCT) or cyclophosphamide-lenalidomide-dexamethasone (CRD), followed by Lenalidomide-based maintenance. We assessed minimal residual disease (MRD) by multi-parameter flow cytometry (MFC) and allelic-specific oligonucleotide real-time quantitative polymerase chain reaction (ASO-RQ-PCR) after consolidation, after 3 and 6 courses of maintenance, and thereafter every 6 months until progression. By MFC analysis, 19/50 patients achieved complete response (CR) after consolidation, and 7 additional patients during maintenance. A molecular marker was identified in 25/50 patients, 4/25 achieved molecular-CR after consolidation, and 3 additional patients during maintenance. A lower MRD value by MFC was found in ASCT patients compared with CRD patients (p=0.0134). Tumor burden reduction was different in patients with high-risk vs standard-risk cytogenetics (3.4 vs 5.2, ln-MFC; 3 vs 6 ln-PCR, respectively) and in patients who relapsed vs those who did not (4 vs 5, ln-MFC; 4.4 vs 7.8 ln-PCR). MRD progression anticipated clinical relapse by a median of 9 months while biochemical relapse by a median of 4 months. MRD allows the identification of a low-risk group, independently of response, and a better characterization of the activity of treatments.

Research Progress on Role of Flow Cytometry in Diagnosis of Multiple Myeloma -Review

Multiple myeloma (MM), the second common malignant tumor in the blood system, is a kind of B cell malignancy and its prognosis is poor. The diagnosis of MM is mainly based on the number of abnormal plasma cells and the presence of monoclonal protein in the blood or urine, but there are limitations for diagnosis of MM. Multi-parameter flow cytometry analysis is increasingly used in the in the diagnosis of MM. Therefore, this review focuses on characteristics of immunophenotypes of malignant plasma cells and myeloma progenitor cells.

Potential use of lymph node-derived HPV-specific T cells for adoptive cell therapy of cervical cancer.

Adoptive transfer of tumor-specific T cells, expanded from tumor-infiltrating lymphocytes or from peripheral blood, is a promising immunotherapeutic approach for the treatment of cancer. Here, we studied whether the tumor-draining lymph nodes (TDLN) of patients with human papillomavirus (HPV)-induced cervical cancer can be used as a source for ACT. The objectives were to isolate lymph node mononuclear cells (LNMC) from TDLN and optimally expand HPV-specific CD4+ and CD8+ T cells under clinical grade conditions. TDLN were isolated from 11 patients with early-stage cervical cancer during radical surgery. Isolated lymphocytes were expanded in the presence of HPV16 E6 and E7 clinical grade synthetic long peptides and IL-2 for 22 days and then analyzed for HPV16 specificity by proliferation assay, multiparameter flow cytometry and cytokine analysis as well as for CD25 and FoxP3 expression. Stimulation of LNMC resulted in expansion of polyclonal HPV-specific T cells in all patients. On average a 36-fold expansion of a CD4+ and/or CD8+ HPV16-specific T cell population was observed, which maintained its capacity for secondary expansion. The T helper type 1 cytokine IFNγ was produced in all cell cultures and in some cases also the Th2 cytokines IL-10 and IL-5. The procedure was highly reproducible, as evidenced by complete repeats of the stimulation procedures under research and under full good manufacturing practice conditions. In conclusion, TDLN represent a rich source of polyclonal HPV16 E6- and E7-specific T cells, which can be expanded under clinical grade conditions for adoptive immunotherapy in patients with cervical cancer.Electronic supplementary materialThe online version of this article (doi:10.1007/s00262-016-1892-8) contains supplementary material, which is available to authorized users.

The expression and function of human CD300 receptors on blood circulating mononuclear cells are distinct in neonates and adults.

Neonates are more susceptible to infections than adults. This susceptibility is thought to reflect neonates’ qualitative and quantitative defects in the adaptive and innate immune responses. Differential expression of cell surface receptors may result in altered thresholds of neonatal immune cell activation. We determined whether the expression and function of the lipid-binding CD300 family of receptors are different on neonatal immune cells compared to adult immune cells. A multiparametric flow cytometry analysis was performed to determine the expression of CD300 receptors on adult peripheral blood mononuclear cells and neonatal cord blood mononuclear cells. The expression of the CD300a inhibitory receptor was significantly reduced on cells from the newborn adaptive immune system, and neonatal antigen presenting cells exhibited a different CD300 receptors expression pattern. We also found differential LPS-mediated regulation of CD300 receptors expression on adult monocytes compared to cord blood monocytes, and that CD300c and CD300e-mediated activation was quantitatively different in neonatal monocytes. This is the first complete study examining the expression of CD300 receptors on human neonatal immune cells compared with adult immune cells. Significant differences in the expression and function of CD300 receptors may help to explain the peculiarities and distinctness of the neonatal immune responses.

Cancer testis antigen MAGE C1 can be used to monitor levels of circulating malignant stem cells in the peripheral blood of multiple myeloma patients.

Monitoring the levels of malignant disease-causing cells in multiple myeloma, as opposed to the clinical symptoms alone, is an important move forward in the management of this disease. While current methods including multiparametric flow cytometry and PCR analysis of the clonal plasma cells can be used in a patient-specific manner, their use is limited and the fundamental malignant progenitor cell is not being monitored. The expression of cancer testis antigen MAGE C1 has been linked to the malignant stem cell in this disease, and thus, we investigated the use of both flow cytometric and qRTPCR approaches to monitor its expression as an alternative monitoring methodology in this pilot study. We compared the levels of MAGE C1 in the peripheral blood to serum M protein and serum beta 2 microglobulin levels at 3-monthly intervals over a 2-year period, for 12 patients on chemotherapy regimens and 4 patients undergoing stem cell transplantation. The analysis indicated that the novel flow cytometric analysis of MAGE C1 expression in the peripheral blood was extremely relevant as a potential minimal residual disease-monitoring tool. Expression of this cancer testis antigen was detectable in all patients throughout treatment, with comparable increases and decreases to serum M protein and/or serum beta 2 microglobulin, but with the advantage of being able to detect disease at a more sensitive level. Furthermore, due to the increased sensitivity, the ability to pre-empt disease relapse before clinical changes were evident, was preliminarily indicated. The qRTPCR approach showed potential as a monitoring tool in the chemotherapy patient cohort, with the mRNA MAGE C1 levels following a similar pattern of expression observed in the flow cytometry analysis.

A global look into human T cell subsets before and after cryopreservation using multiparametric flow cytometry and two-dimensional visualization analysis

The cryopreservation of human lymphocytes is an essential step for the achievement of several cellular therapies. Besides, T cells are considered as promising actors in cancer therapy for their cytotoxic and regulatory properties. Consequently, the development of tools to monitor the impact of freezing and thawing processes on their fine distribution may be an asset to achieve quality control in cellular therapy. In this study, the phenotypes of freshly isolated human mononuclear cells were compared to those observed following one cycle of cryopreservation and rest periods 0h, 1h and 24h after thawing but before staining. T cells were scrutinized for their distribution according to naive, memory effector, regulatory and helper subsets. Flow cytometry analyses were done using eight-color antibody panels as proposed by the Human Immunophenotyping Consortium. Data were further analyzed by using conventional directed gating and clustering software, namely SPADE and viSNE. Overall, SPADE and viSNE tools were very efficient to monitor the outcome of PBMC populations and T cell subsets. T cells were more sensitive to cryopreservation than other cells. Our results indicated that submitting the thawed cells to a 1h rest period improved the detection of some cell markers when compared to fresh samples. In contrast, cells submitted to a 24h rest period, or to none, were less representative of fresh sample distribution. The heterogeneity of PBMC, as well as the effects of freeze-thaw cycle on their distribution, can be easily monitored by using SPADE and viSNE.

Pre- and post-transplant quantification of measurable ('minimal') residual disease via multiparameter flow cytometry in adult acute myeloid leukemia.

Measurable (“minimal”) residual disease (MRD) before or after hematopoietic cell transplantation (HCT) identifies adults with AML at risk of poor outcomes. Here, we studied whether peri-transplant MRD dynamics can refine risk assessment. We analyzed 279 adults receiving myeloablative allogeneic HCT in first or second remission who survived at least 35 days and underwent 10-color multiparametric flow cytometry (MFC) analyses of marrow aspirates before and 28±7 days after transplantation. MFC-detectable MRD before (n=63) or after (n=16) transplantation identified patients with high relapse risk and poor survival. Forty-nine patients cleared MRD with HCT conditioning, whereas 2 patients developed new evidence of disease. The 214 MRDneg/MRDneg patients had excellent outcomes, whereas both MRDneg/MRDpos patients died within 100 days following transplantation. For patients with pre-HCT MRD, outcomes were poor regardless of post-HCT MRD status, although survival beyond 3 years was observed among the 58 patients with decreasing but not the 7 patients with increasing peri-HCT MRD levels. In multivariable models, pre-HCT but not post-HCT MRD was independently associated with OS and RR. These data indicate that MRDpos patients before transplantation have a high relapse risk regardless of whether or not they clear MFC-detectable disease with conditioning and should be considered for pre-emptive therapeutic strategies.

Multiparametric flow cytometric analysis of whole blood reveals changes in minor lymphocyte subpopulations of multiple sclerosis patients

Objective: The objective of this study is to characterise the functionally relevant minor lymphocyte subpopulations in whole blood of multiple sclerosis (MS) patients and their potential utility as biomarkers for treatment follow up. Material and methods: Peripheral blood from 40 healthy donors (HD) and 66 MS patients [23 relapsing–remitting (RRMS) without treatment, 27 RRMS undergoing treatment (16 IFN-β, 11 natalizumab), and 16 progressive forms (eight secondary progressive and eight primary progressive)] was analysed by multiparametric flow cytometry. Results: Untreated MS patients showed a decrease in early effector memory (CD45RA−CCR7−CD27+) CD4+ and CD8+ T cells and an increase in Th17 lymphocytes in peripheral blood compared with HD. Regarding the effect of treatment, whereas no differences in relative percentages of cellular subpopulations were observed in patients under IFN-β treatment, those under treatment with natalizumab had an increased percentage of early effector memory CD4+ (CD45RA−CCR7−CD27+), central memory CD8+ (CD45RA−CCR7+CD27+) T cells, recent thymic emigrants (CD4+ CD45RA+CCR7+CD27+CD31+PTK7+) and transitional B cells (CD19+CD27−CD24hiCD38hi). Conclusions: Multiparametric flow cytometry analysis of whole blood is a robust, reproducible, and sensitive technology to monitor the effect of MS treatments even in minor lymphocyte subpopulations that might represent useful biomarkers of treatment response.

Bone Marrow Involvement Detected By Multi-Parameter Flow Cytometry Predicts Poor Outcome after Autologous Stem Cell Transplantation for Peripheral T-Cell Lymphoma

BACKGROUND: Peripheral T-cell lymphomas (PTCL) encompass a heterogeneous group of neoplasms accounting for 10 to 15% of non-Hodgkin lymphomas worldwide. Prognosis for PTCL patients is poor and consolidation in first remission with autologous stem cell transplantation (ASCT) is widely used. Most patients though still relapse after transplant. We hypothesized that pre-ASCT bone marrow (BM) involvement detected by multi-parameter flow cytometry (FC) would identify patients with inferior outcome after ASCT.METHODS: We retrospectively analyzed the outcome of 29 consecutive PTCL patients who underwent ASCT at the Fred Hutchinson Cancer Research Center from April 2004 through July 2014. Pre-ASCT BM involvement by flow cytometry (FC) was defined as the presence of an abnormal T-cell population detected by multi-parameter FC analysis in a BM aspirate obtained within 30 days prior to ASCT. An abnormal T-cell population accounting for a percentage equal or greater than 0.01% of total leukocytes after red blood cell lysis was considered significant.RESULTS: Ten patients (34%) with angioimmunoblastic T cell lymphoma (AITCL), 8 (27%) with ALK-negative anaplastic large cell lymphoma (ALCL), 8 (27%) with peripheral T cell lymphoma, not otherwise specified (PTCL-NOS) and 3 (12%) with other PTCL sub-types were included. Median age at transplant was 54 (range: 29-71). Twenty patients (76%) presented at ASCT in complete remission (CR) per 1999 Cheson criteria and 9 (31%) were in first CR (CR1). Fifteen patients (50%) underwent ASCT upfront. Pre-ASCT BM involvement was detected by FC analysis in 7 patients (24%, 3 patients with AITCL, 1 patient with ALCL and 3 patients with PTCL-NOS) and by morphology in 2 patients (7%, 2 patients with AITCL). The 7 patients with pre-ASCT BM involvement detected by FC experienced a significantly higher 4-year cumulative incidence of relapse (CIR) (85% versus 36%, p < 0.001) and lower overall survival (OS) (19% versus 89%, p < 0.001) with a median follow-up of 51 months. These findings were confirmed in multivariable analysis for CIR (HR = 7.37, CI = 1.14 - 47.61, p = 0.03) and OS (HR = 7.04, CI = 1.29 - 38, p = 0.024). The IPI score, absence or presence of CR1 and the number of prior therapies were included in a multivariable model for CIR, while age and the IPI score at diagnosis were taken into account for OS. ASCT performed in CR1 was associated with lower CIR (HR = 0.11, CI = 0.03-0.041, p < 0.001). Histologic subtypes did not impact CIR (p = 0.97) nor OS (p = 0.91) and they did not significantly differ between the groups with and without pre-ASCT BM involvement detected by FC (p = 0.60) after applying Fisher's exact test. Further analysis of the 22 patients presenting in CR at ASCT revealed that in this subgroup, pre-ASCT BM involvement by FC (n = 4) was also associated with higher CIR (75% versus 32%, p = 0.002) and lower OS (25 versus 94%, p <0.001). The prognostic impact of pre-ASCT BM involvement by FC persisted in multivariable analysis for CIR (HR = 16, CI = 1.11-228.70, p = 0.042, IPI score at diagnosis and number of prior therapies considered as covariables) but not for OS (HR = 0.15, CI = 0.65-65.40, p = 0.10, multivariable model including age and the IPI score at diagnosis).CONCLUSION: Pre-ASCT BM involvement by FC correlated with dramatically higher relapse rates and an inferior OS in PTCL patients after ASCT. Furthermore, we demonstrate that residual disease, detected only in patients meeting Cheson 1999 criteria for CR at ASCT is capable of predicting a higher risk for relapse. These findings should encourage further evaluation of minimal residual disease in PTCL patients achieving complete remission as defined per Cheson 1999 and 2007 criteria. [Display omitted] [Display omitted] DisclosuresGopal:Merck: Research Funding; Emergent/Abbott: Research Funding; Cephalon/Teva: Research Funding; BioMarin: Research Funding; Sanofi-Aventis: Honoraria; Millenium: Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Spectrum: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Piramal: Research Funding; Biogen Idec, BMS: Research Funding. Maloney:Juno Therapeutics: Research Funding; Roche/Genentech: Honoraria; Janssen Scientific Affairs: Honoraria; Seattle Genetics: Honoraria. Till:Roche-Genentech: Research Funding.

Flow cytometry screening for paroxysmal nocturnal hemoglobinuria: A single-center experience in Saudi Arabia.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal hematopoietic stem cell disorder, characterized by the deficiency of glycosylphosphatidylinositol (GPI) that anchors proteins in cell membranes. PNH is manifest variously with hemoglobinuria, thrombosis, or bone marrow failure. This retrospective study was aimed at assessing the incidence and characteristics of patients diagnosed with PNH in the King Fisal Specialist Hospital and research center. Patients referred for PNH diagnosis at King Faisal Specialist Hospital and Research Centre, Riyadh, during the 2-year period (2012-2013) were included in the analysis. Peripheral blood samples were used for multi-parametric flow cytometry analysis based on fluorescent inactive aerolysin (FLAER), and the markers, CD235a and CD59 on red blood cells (RBCs), and CD14, CD45, CD64, CD24, and CD15 on white blood cells (WBCs) exclusively monocytes and granulocytes. Univariate analysis of the disease characteristics was performed. Of the 366 samples submitted for PNH screening, 14 were positive (4%) and 11 were evaluable. Of the 11 patients analyzed, 8 patients (73%) presented with aplastic anemia, 1 patient (9%) each with pancytopenia, Budd-Chiari syndrome, and immune thrombocytopenia purpura. All samples showed type II and III GPI-deficient clones with a median clone size of 15% (range, 0.7%-56%) in the RBCs, and 63% (range, 3.8%-100%) in WBCs (monocytes and granulocytes). This study confirms the rarity of PNH and its predominant presentation as aplastic anemia or thrombosis in a Saudi Arabian population, similar to the worldwide incidence.