Profile Of Subsets Research Articles

Immune cell profiling of the ICAM1 p.K56M heart failure with preserved ejection fraction risk variant.

Intercellular adhesion molecule-1 (ICAM-1) facilitates inflammation via leucocyte recruitment and has been implicated in heart failure with preserved ejection fraction (HFpEF). Approximately 35% of African American individuals carry a copy of an ICAM1 missense variant (rs5491; p.K56M), which is associated with an increased risk of HFpEF. The pathways by which rs5491 increases HFpEF risk are not well defined. We evaluated the circulating immune cell profile of rs5491. Among African American individuals in the Multi-Ethnic Study of Atherosclerosis, we evaluated the associations of rs5491 with 29 circulating peripheral blood mononuclear cell subsets. The top immune cells were then related to echocardiographic measures of structure and function. Among 502 individuals with immune cell profiling (mean age 63years, 51% female), 191 individuals (38%) had at least one copy of rs5491. Each additional rs5491 allele was significantly associated with higher proportions of Tc17 CD8+ cytotoxic T cells (β=1.34, SE=0.45, P=9.5×10-5) and Tc2 CD8+ cytotoxic T cells (β=1.19, SE=0.44, P=0.00012). There were no other associations noted between rs5491 and the remaining immune cells. A higher proportion of Tc17 cells was significantly associated with a higher left ventricular ejection fraction, E/e' average and right ventricular systolic pressure (RVSP), while a higher proportion of Tc2 cells was significantly associated with a higher RVSP. The ICAM1 p.K56M variant (rs5491) carries a distinct and inflammatory T-cell subset profile. These cytotoxic T cells are in turn associated with alterations in cardiac function and adverse haemodynamics later in life, thus providing insight into pathways by which rs5491 may increase the risk of HFpEF.

Proteomic and phenotypic characteristics of memory-like natural killer cells for cancer immunotherapy

BackgroundHuman and mouse natural killer (NK) cells have been shown to develop memory-like function after short-term exposure to the cocktail of IL-12/15/18 or to overnight co-culture with some tumor cell...

Immunomodulation profile of the biosimilar trastuzumab MYL-1401O in a bioequivalence phase I study

The initial Phase-I single centre, single dose, randomized, double-blind, cross-over study was planned to assess the pharmacokinetic and pharmacodynamic bioequivalence of the trastuzumab biosimilar (MYL-1401O) compared to the reference Herceptin®. Their respective immunomodulation profile presented in this paper involved healthy males receiving a single infusion of both monoclonals, separated by a washout period. Sixty parameters were assessed in total, including serum cytokines, peripheral mononuclear cell (PBMC) subsets, cell activation and response to recall antigens and mitogen, pre- and post- infusion, as well as a cytokine release assay (CRA) at baseline. Trastuzumab infusion induced a transient and weak peak of serum IL-6 at 6 h, and a modulation of mononuclear cell subset profile and activation level, notably CD16 + cells. Except for CD8 + T cells, there were no significant differences between Herceptin® and MYL-1401O. In CRA, PBMC stimulated with MYL-1401O or Herceptin® similarly secreted IL-6, TNF-α, IL-1β, GM-CSF, IFN-γ, and IL-10, but no or low level of IL-2. Interestingly, some observed adverse events correlated with IL-2 and IFN-γ in CRA. MYL-1401O exhibited a very similar immunomodulation profile to Herceptin®, strongly supporting its bioequivalence. This approach may thus be included in a proof-of-concept study. CRA may be used as a predictive assay for the evaluation of clinical monoclonals.

Deciphering the heterogeneity dominated by tumor-associated macrophages for survival prognostication and prediction of immunotherapy response in lung adenocarcinoma

Tumor-associated macrophages (TAMs) are a specific subset of macrophages that reside inside the tumor microenvironment. The dynamic interplay between TAMs and tumor cells plays a crucial role in the treatment response and prognosis of lung adenocarcinoma (LUAD). The study aimed to examine the association between TAMs and LUAD to advance the development of targeted strategies and immunotherapeutic approaches for treating this type of lung cancer. The study employed single-cell mRNA sequencing data to characterize the immune cell composition of LUAD and delineate distinct subpopulations of TAMs. The “BayesPrism” and “Seurat” R packages were employed to examine the association between these subgroups and immunotherapy and clinical features to identify novel immunotherapy biomarkers. Furthermore, a predictive signature was generated to forecast patient prognosis by examining the gene expression profile of immunotherapy-associated TAMs subsets and using 104 machine-learning techniques. A comprehensive investigation has shown the existence of a hitherto unidentified subgroup of TAMs known as RGS1 + TAMs, which has been found to have a strong correlation with the efficacy of immunotherapy and the occurrence of tumor metastasis in LUAD patients. CD83 was identified CD83 as a distinct biomarker for the expression of RGS1 + TAMs, showcasing its potential utility as an indicator for immunotherapeutic interventions. Furthermore, the prognostic capacity of the RTMscore signature, encompassing three specific mRNA (NR4A2, MMP14, and NPC2), demonstrated enhanced robustness when contrasted against the comprehensive collection of 104 features outlined in the published study. CD83 has potential as an immunotherapeutic biomarker. Meanwhile, The RTMscore signature established in the present study might be beneficial for survival prognostication.

Male patients with primary Sjögren's syndrome have unique clinical manifestations and circulating lymphocyte profiles.

We aimed to explore the relationship between clinical characteristics and circulating lymphocyte profiles in Chinese male patients with primary Sjögren's syndrome (pSS). Data from 397 patients with pSS were analyzed retrospectively. 37 were male, which is a prevalence of 9.3%. The clinical, laboratory, and immunophenotypic profiles of peripheral blood lymphocyte subsets were compared between male and female pSS patients. Male patients with primary Sjögren's syndrome have unique clinical manifestations and circulating lymphocyte profiles. Male patients complained more about xerophthalmia and presented with more extra-glandular manifestations as compared with female patients. The CD4+/CD8+ ratio (P = 0.030), the prevalence of CD4-CD8- T cells in lymphocytes (P = 0.020), the absolute number of CD4-CD8- T cells (P = 0.035), the prevalence of CD4+ T cells in lymphocytes (P < 0.001), and the absolute number of CD4+ T cells (P = 0.023) were significantly lower in male patients compared to female patients. On the other hand, the prevalence of CD8+CD28+ T cells (P = 0.030) and CD4+CD25high T cells (P = 0.040) in lymphocytes was significantly higher in male patients than in female patients. Moreover, compared to females with pSS, an elevated serum IgG level, low C3 and C4 levels, anti-SSB positivity, and ANA titers of ≥ 1:160 positivity were more frequent in male with pSS. Male patients with pSS have distinctive peripheral blood lymphocyte subpopulations, present with more severe clinical symptoms and immunological features, and have an unfavorable prognosis. Key Points • Male patients with pSS have more severe clinical symptoms and specific characteristics of peripheral blood lymphocyte subsets. • Male pSS patients exhibit a higher intensity of the disease (as evaluated by ESSDAI). • Male patients with pSS require individualized treatment regimens and closer follow-up.

Abstract 1332: Allogeneic CD19-directed CAR-iNKT cells and their phenotypic subsets for the treatment of CD19+ hematological malignancies

Abstract Invariant Natural Killer T (iNKT) cells are a unique subset of innate lymphocytes, constituting &amp;lt;1% of human T cells. iNKT cells express a semi-invariant TCR (iTCR) recognizing glycolipids presented by the monomorphic, MHC-like molecule CD1d. Previous studies indicate that due to distinctive TCR constitution and antigen recognition properties, iNKT cells do not induce acute graft-versus-host disease. Based on the CD4 and CD8 expression, mature human iNKT cells can be classified into CD4+CD8-, CD4-CD8- &amp; CD4-CD8+ subsets with overlapping and distinct functions. The functional profiling of CAR19-iNKT cell subsets serves the dual purpose of ensuring their safety and efficacy as a therapeutic intervention. Here we characterized the phenotypic and functional profile of CD4+ and CD4- CAR19-iNKT cells. iNKT cells were isolated with &amp;gt;99% purity from healthy donors' peripheral blood and were transduced with a CD19 CAR-encoding 3rd generation lentivirus. After expansion, the CAR19-iNKT cells were cryopreserved and later analyzed post-thawing. Differential expression of CD27 and PD1 was noted in CAR+CD4+ and CAR+CD4- iNKT cells compared to other markers. For functional profiling, CAR+CD4+ iNKT cells were positively selected, and 24h cytotoxicity assays were performed using several tumor cell lines including SEM, Ramos and C1R-CD1d (+/- α-GalCer). The CAR+CD4- iNKT cells exhibited superior cytotoxicity to multiple tumor cell lines compared to that of CAR+CD4+ iNKT cells from two donors. However, both subsets lysed α-GalCer pulsed C1R-CD1d cells in a comparable manner indicating the potential of these subsets to recognize antigen through the iTCR. Subsequently, we assessed the proliferation ability of the CAR+CD4+ and CAR+CD4- subsets by exposing the cells to three rounds of stimulation, 24h apart, using SEM (CD19+CD1d-) or K562 (CD19-CD1d-) tumor cells with or without IL-15. Proliferation was assessed seven days following the first stimulation. The CAR+CD4+ subset of CAR19-iNKT cells demonstrated faster proliferation than CAR+CD4- cells in the presence of IL-15 after repeated exposure to tumor cells. Ongoing RNA seq analysis of CAR+CD4+/CAR+CD4- cells will further elucidate differences between these subsets. The outcomes of these studies have shown encouraging results, indicating the potential benefit of having diverse subsets among CAR19-iNKT cells for treating CD19+ cancers. The therapeutic potential of CAR+CD4+ iNKT cell subset could be enhanced to match that of CAR+CD4- subset with the use of α-GalCer. In summary, inclusion of both CD4+ and CD4- iNKT cells is critical for the functionality of allogeneic CAR-iNKT cell therapy. Extensive characterization is crucial for clinical translation, but additional research, including preclinical and clinical trials, is essential to determine the safety and effectiveness of CAR19-iNKT cell therapy in real-world applications. Citation Format: Kanagaraju Ponnusamy, Simon Poon, Nicole van der Weerden, Robson Dossa, Michael J. Baker, Mini Bharathan, Anastasios Karadimitris. Allogeneic CD19-directed CAR-iNKT cells and their phenotypic subsets for the treatment of CD19+ hematological malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1332.

Circulating tumor-associated antigen-specific IFNγ+4-1BB+ CD8+ T cells as peripheral biomarkers of treatment outcomes in patients with pancreatic cancer.

CD8+ T cells affect the outcomes of pancreatic ductal adenocarcinoma (PDAC). Using tissue samples at pre-treatment to monitor the immune response is challenging, while blood samples are beneficial in overcoming this limitation. In this study, we measured peripheral antigen-specific CD8+ T cell responses against four different tumor-associated antigens (TAAs) in PDAC using flow cytometry and investigated their relationships with clinical features. We analyzed the optimal timing within the treatment course for effective immune checkpoint inhibition in vitro. We demonstrated that the frequency of TAA-specific IFNγ+4-1BB+ CD8+ T cells was correlated with a fold reduction in CA19-9 before and after neoadjuvant therapy. Moreover, patients with TAA-specific IFNγ+4-1BB+ CD8+ T cells after surgery exhibited a significantly improved disease-free survival. Anti-PD-1 treatment in vitro increased the frequency of TAA-specific IFNγ+4-1BB+ CD8+ T cells before neoadjuvant therapy in patients, suggesting the importance of the timing of anti-PD-1 inhibition during the treatment regimen. Our results indicate that peripheral immunophenotyping, combined with highly sensitive identification of TAA-specific responses in vitro as well as detailed CD8+ T cell subset profiling via ex vivo analysis, may serve as peripheral biomarkers to predict treatment outcomes and therapeutic efficacy of immunotherapy plus neoadjuvant chemotherapy.

Distinctive CD56dim NK subset profiles and increased NKG2D expression in blood NK cells of Parkinson’s disease patients

Mounting data suggest an important role for the immune system in Parkinson’s disease (PD). Previous evidence of increased natural killer (NK) cell populations in PD suggests a potential role of NK cells in the pathogenesis of the disease. Previous studies have analyzed NK cell populations using aggregation by variable expression of CD56 and CD16. It remains unknown what differences may exist between NK cell subpopulations when stratified using more nuanced classification. Here, we profile NK cell subpopulations and elucidate the expressions of activating, NKG2D, inhibitory, NKG2A, and homing, CX3CR1, receptors on NK cell subpopulations in PD and healthy controls (HC). We analyzed cryopreserved PMBC samples using a 10-color flow cytometry panel to evaluate NK cell subpopulations in 31 individuals with sporadic PD and 27 HC participants. Here we identified significant differences in the CD56dim NK subset that changes with disease severity in PD. Furthermore, the expressions of NKG2D in all three NK cell subsets were significantly elevated in PD patients compared to HC. Notably, NKG2A expression in the CD56bright NK subset increased in PD patients with longer disease duration but there were no changes in CX3CR1. In summary, our data suggests that changes in NK cells may be influenced by the clinical severity and duration of PD.

Abstract TP295: Temporal Characterization of Immune Responses in the Rat Brain Following Ischemic Stroke Using In-Depth Flow Cytometry Panels

Introduction: Rat models are widely used in stroke research as they are well suited for behavior studies and brain imaging techniques. However, methods for studying immune responses and identifying distinct leukocyte subsets in rats lag behind mice in part due to lack of specific antibodies for flow cytometry. Several flow cytometry antibody panels have been used to study the immune response of the rat brain after stroke, but they did not distinguish between pro- and anti-inflammatory macrophages, which is critical for stroke-induced neuroinflammation research. Here, we developed flow cytometry panels to measure myeloid and lymphoid leukocyte subsets in rat brain, blood, and spleen, with an emphasis on macrophage subtypes, and validated them in an ischemic stroke model. Method: Adult male (8-12 wk old) Nude and Sprague Dawley (SD) rats were subjected to distal MCAO. Ipsi- and contralateral hemispheres, blood, and spleen were collected and analyzed by flow cytometry at different time points post-stroke. Cell populations were sorted using FACS and characterized using qPCR or morphological analysis to confirm our FACS gating strategy. Results: We discriminated microglia, 3 monocyte/macrophage subsets, granulocytes, dendritic cells, NK cells, B cells, and T cells in the brain and periphery. The temporal profile of leukocyte subsets after stroke resembled those observed in mice, validating the reliability of our antibody panels: granulocytes and monocytes peaked in the first 2-3 days post-stroke, B and T cells peaked around 4-5 days, followed by a gradual increase of ‘microglia’ over 14 days. Using a combination of CD43 and His48 to differentiate monocyte/macrophage subpopulations, we observed a shift in these subsets over time, akin to the shift from pro- to anti-inflammatory macrophages reported in stroke-injured mouse brains. Notably, Nude rats differed from the SD rats in terms of His48 expression; SD rat brain monocyte/macrophage population was predominantly His48lo, while Nude rats had both His48lo and His48hi subsets. Conclusion: Our flow cytometry panels for rats distinguished leukocyte subsets, including monocyte/macrophage subpopulations, providing a valuable tool to study the complex immune responses in rat models of neurological disorders.

OMIP-100: A flow cytometry panel to investigate human neutrophil subsets.

This 14-color, 13-antibody optimized multicolor immunofluorescence panel (OMIP) was designed for deep profiling of neutrophil subsets in various types of human samples to contextualize neutrophil plasticity in a range of healthy and diseased states. Markers present in the OMIP allow the profiling of neutrophil subsets associated with ontogeny, migration, phagocytosis capacity, granule release, and immune modulation. For panel design, we ensured that the commonly available fluorophores FITC/AF488, PE, and APC were assigned to the intracellular subset marker Olfactomedin 4, the maturity and activation marker CD10, and whole blood subset marker CD177, respectively. These markers can be easily replaced without affecting the core identification of neutrophils, enabling antibodies to new neutrophil antigens of interest or for fluorescent substrates to assess different neutrophil functions to be easily explored. Panel optimization was performed on whole blood and purified neutrophils. We demonstrate applications on clinical samples (whole blood and saliva) and experimental endpoints (purified neutrophils stimulated through an in vitro transmigration assay). We hope that providing a uniform platform to analyze neutrophil plasticity in various sample types will facilitate the future understanding of neutrophil subsets in health and disease.

Comprehensive profiling of cell subsets of gastric cancer and liver metastasis based on single cell RNA-sequencing analysis.

Liver metastasis (Li) is one of the most common distant metastatic sites for gastric cancer. A deeper understanding of its mechanism of action from a bioinformatics perspective may provide new insights. Therefore, the aim of this study was to use single cell RNA sequencing (scRNA-seq) to evaluate cell subtypes and understand the molecular mechanism of gastric cancer Li. The scRNA-seq data GSE163558 of gastric cancer and Li were downloaded from Gene Expression Omnibus (GEO). Single cell data were analyzed by various R packages such as Seurat, CellChat, gene set variation analysis (GSVA), monocle, gene set enrichment analysis (GSEA), and survival analysis and the results were plotted by ggplot2, R4.1.1. Protein expression was confirmed by immunohistochemistry in an additional patient cohort. The genes APOD, CXCL5, and JUN are involved in epithelial cell metastasis. The infiltration of cytotoxic CD8 T cells was more frequent in gastric primary tumors (PTs) than in Lis. IL7R high natural killer (NK) cells that had high TXNIP and RIPOR2 expression were located at the site of Li and corresponded to a favorable prognosis. NK cells with high TNFAIP3 expression were located at the PT site and corresponded to a poor prognosis. Furthermore, the gene expression of myeloid cells was different depending on their localization in the PT site or Li. MHC-I signaling pathway was found to be activated in the PT compared to MHC-II at the site of Li, as revealed by cell-cell interaction, and HLA-E-CD94/NKG2A of NK cells was only activated in the PT and not in the Li. The present study revealed the difference between Li and gastric PT by scRNA-seq, demonstrating the impact of partial gene expression on patient prognosis. Our study provides new insights into gastric cancer and Li.

The significance of CD16+ monocytes in the occurrence and development of chronic thromboembolic pulmonary hypertension: insights from single-cell RNA sequencing.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a serious pulmonary vascular disease characterized by residual thrombi in the pulmonary arteries and distal pulmonary microvascular remodeling. The pathogenesis of CTEPH remains unclear, but many factors such as inflammation, immunity, coagulation and angiogenesis may be involved. Monocytes are important immune cells that can differentiate into macrophages and dendritic cells and play an important role in thrombus formation. However, the distribution, gene expression profile and differentiation trajectory of monocyte subsets in CTEPH patients have not been systematically studied. This study aims to reveal the characteristics and functions of monocytes in CTEPH patients using single-cell sequencing technology, and to provide new insights for the diagnosis and treatment of CTEPH. Single-cell RNA sequencing (scRNA-seq) were performed to analyze the transcriptomic features of peripheral blood mononuclear cells (PBMCs) from healthy controls, CTEPH patients and the tissues from CTEPH patients after the pulmonary endarterectomy (PEA). We established a CTEPH rat model with chronic pulmonary embolism caused by repeated injection of autologous thrombi through a central venous catheter, and used flow cytometry to detect the proportion changes of monocyte subsets in CTEPH patients and CTEPH rat model. We also observed the infiltration degree of macrophage subsets in thrombus tissue and their differentiation relationship with peripheral blood monocyte subsets by immunofluorescence staining. The results showed that the monocyte subsets in peripheral blood of CTEPH patients changed significantly, especially the proportion of CD16+ monocyte subset increased. This monocyte subset had unique functional features at the transcriptomic level, involving processes such as cell adhesion, T cell activation, coagulation response and platelet activation, which may play an important role in pulmonary artery thrombus formation and pulmonary artery intimal remodeling. In addition, we also found that the macrophage subsets in pulmonary endarterectomy tissue of CTEPH patients showed pro-inflammatory and lipid metabolism reprogramming features, which may be related to the persistence and insolubility of pulmonary artery thrombi and the development of pulmonary hypertension. Finally, we also observed that CD16+ monocyte subset in peripheral blood of CTEPH patients may be recruited to pulmonary artery intimal tissue and differentiate into macrophage subset with high expression of IL-1β, participating in disease progression. CD16+ monocytes subset had significant gene expression changes in CTEPH patients, related to platelet activation, coagulation response and inflammatory response. And we also found that these cells could migrate to the thrombus and differentiate into macrophages with high expression of IL-1β involved in CTEPH disease progression. We believe that CD16+ monocytes are important participants in CTEPH and potential therapeutic targets.

Lipids in the tumor microenvironment: immune modulation and metastasis.

Tumor cells can undergo metabolic adaptations that support their growth, invasion, and metastasis, such as reprogramming lipid metabolism to meet their energy demands and to promote survival in harsh microenvironmental conditions, including hypoxia and acidification. Metabolic rewiring, and especially alterations in lipid metabolism, not only fuel tumor progression but also influence immune cell behavior within the tumor microenvironment (TME), leading to immunosuppression and immune evasion. These processes, in turn, may contribute to the metastatic spread of cancer. The diverse metabolic profiles of immune cell subsets, driven by the TME and tumor-derived signals, contribute to the complex immune landscape in tumors, affecting immune cell activation, differentiation, and effector functions. Understanding and targeting metabolic heterogeneity among immune cell subsets will be crucial for developing effective cancer immunotherapies that can overcome immune evasion mechanisms and enhance antitumor immunity.

The profile and prognostic significance of bone marrow T-cell differentiation subsets in adult AML at diagnosis.

T lymphocytes in tumor microenvironment play a pivotal role in the anti-tumor immunity, and the memory of T cells contributes to the long-term protection against tumor antigens. Compared to solid tumors, studies focusing on the T-cell differentiation in the acute myeloid leukemia (AML) bone marrow (BM) microenvironment remain limited. Fresh BM specimens collected from 103 adult AML patients at diagnosis and 12 healthy donors (HDs) were tested T-cell differentiation subsets by multi-parameter flow cytometry. CD4 and CD8 T-cell compartments had different constituted profiles of T-cell differentiated subsets, which was similar between AML patients and HDs. Compared to HDs, AML patients as a whole had a significantly higher proportion of CD8 effector T cells (Teff, P = 0.048). Moreover, the T-cell compartment of AML patients with no DNMT3A mutations skewed toward terminal differentiation at the expense of memory T cells (CD4 Teff: P = 0.034; CD8 Teff: P = 0.030; CD8 memory T: P = 0.017), whereas those with mutated DNMT3A had a decrease in CD8 naïve T (Tn) and CD4 effector memory T cells (Tem) as well as an increase in CD4 central memory T cells (Tcm) (P = 0.037, 0.053 and 0.053). Adverse ELN genetic risk correlated with a lower proportion of CD8 Tn. In addition, the low proportions of CD4 Tem and CD8 Tn independently predicted poorer relapse-free survival (RFS, HR [95%CI]: 5.7 (1.4-22.2), P = 0.017 and 4.8 [1.3-17.4], P = 0.013) and event-free survival (EFS, HR [95% CI]: 3.3 (1.1-9.5), P = 0.029; 4.0 (1.4-11.5), P = 0.010), respectively. AML patients had abnormal profiles of BM T-cell differentiation subsets at diagnosis, which was related to DNMT3A mutations. The low proportions of CD4 Tem and CD8 Tn predicted poor outcomes.

Prediction of intravenous immunoglobulin retreatment inchildren with Kawasaki disease using models combininglymphocyte subset and cytokine profile inanEast Asian cohort.

For children with Kawasaki disease (KD) at high risk of developing coronary artery lesions and requiring retreatment with intravenous immunoglobulin (IVIG), the availability of accurate prediction models remains limited because of inconsistent variables and unsatisfactory prediction results. We aimed to construct models to predict patient's probability of IVIG retreatment combining children's individual inflammatory characteristics. Clinical manifestations and laboratory examinations of 266 children with KD were retrospectively analysed to build a development cohort data set (DC) and a validation cohort data set (VC). In the DC, binary logistic regression analyses were performed using R language. Nomograms and receiver operating curves were plotted. The concordance index (C index), net reclassification index, integrated discrimination improvement index and confusion matrix were applied to evaluate and validate the models. Models_5V and _9V were established. Both contained variables including the percentages of CD8+ Tcells, CD4+ Tcells, CD3+ Tcells, levels of interleukin (IL)-2R and CRP. Model_9V additionally included variables for IL-6, TNF-α, NT-proBNP and sex, with a C index of 0.86 (95% CI 0.79-0.92). When model_9V was compared with model_5V, the NRI and IDI were 0.15 (95% CI 0.01-0.30, P < 0.01) and 0.07 (95% CI 0.02-0.12, P < 0.01). In the VC, the sensitivity, specificity and precision of model_9V were 1, 0.875 and 0.667, while those of model_5V were 0.833, 0.875 and 0.625. Model_9V combined cytokine profiles and lymphocyte subsets with clinical characteristics and was superior to model_5V achieving satisfactory predictive power and providing a novel strategy early to identify patients who needed IVIG retreatment.

Expression of a Novel Chimeric Inhibitory Receptor Attenuates CD19 CAR T Cells: A Promising Strategy for Toxicity Mitigation

Introduction Chimeric antigen receptor (CAR) T cells targeting CD19 are highly effective in patients with refractory/relapsed acute lymphoblastic leukemia and lymphoma but often trigger severe cytokine release syndrome (sCRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). For r/rALL patients, as many as 77% develop Grade 3-5 CRS and 40% Grade 3-5 ICANS. sCRS occurs when hyperactivated CAR T cells undergo exponential expansion accompanied by the release of excessive amounts of inflammatory cytokines. This leads to a systemic pro-inflammatory state that can cause hypotension, multi-organ failure and even death. Tocilizumab is the only FDA-approved drug for CRS and despite concurrent corticosteroids, often fails to control CRS. Attempts to improve safety have been proposed, but have significant limitations, such as permanent removal of CARs. New and innovative methods to mitigate toxicities are needed. The purpose of this study was to design and test the efficacy of a novel autoregulatory element in the form of a chimeric inhibitory receptor (CIR), that when engaged by a specific CRS-associated pro-inflammatory molecule would trigger inhibitory signaling within CAR T cells. We hypothesize that as cytokine levels increase following activation, these signals can be redirected through responsiveness of the CIR, leading to an attenuation of CAR activity. In this study, we have tested a CIR construct that couples the recognition of IFNγ to the signaling domain of the TIGIT inhibitory receptor. We co-expressed this CIR with a CD19.28ζ CAR to evaluate its ability to attenuate activation and cytokine production and to assess its cytotoxic activity. Methods An anti-IFNγ scFv followed by the transmembrane and intracellular domains of TIGIT were arranged in sequence with the truncated EGFR receptor followed by the CD19.28ζ FMC63 CAR with intervening T2A cleavage domains and cloned into a retroviral backbone. Transduction efficiency was assessed by staining with biotinylated CD19-Fc protein or biotinylated EGFR. Following expansion, memory and effector cell differentiation was evaluated by staining for CD45RO, CD45RA, CCR7, CD127, and CD95. Activation following stimulation with NALM-6 tumor cells was measured by staining for CD69, CD25, CD38, PD-1, and CD107a. Cytotoxicity was evaluated using bioluminescence. To mimic cell types present during CRS, we utilized a coculture assay that consists of CAR T cells, NALM-6 tumor cells, and either macrophages or dendritic cells (DC) differentiated from autologous CD14 + monocytes. Cocultures were incubated for 48 hr. and supernatants were collected for analyses by Luminex. Results CD19 CARs co-expressing a CIR composed of an anti-IFNγ scFv coupled to TIGIT inhibitory signaling expanded during the manufacturing process as well as T cells expressing only CD19 CAR and displayed normal levels of CAR expression. The presence of the CIR did not affect the differentiation profile of memory and effector subsets. CIR-expressing CD19 CARs exhibited robust tumor cell killing of NALM-6 targets equivalent to CD19 CARs. Next, CD19 CAR/CIR cells were pretreated with IFNγ for 24 hr. and then cultured with NALM-6 cells. Exposure to IFNγ resulted in a significant abrogation in cytotoxicity, which was eventually restored with time. Activation profile analysis of CARs equipped with CIR signaling after target stimulation revealed an overall diminution of CARs expressing multiple (4 or 5) activation markers relative to CD19 CARs. Importantly, CIR signaling resulted in significant reductions in the levels of effector, stimulatory, and inflammatory mediators including IFNγ, TNFα, GM-CSF, and IL-17. CARs expressing the CIR exhibited slower killing kinetics when challenged with sequential stimulations by fresh tumor cells. However, in vivo anti-tumor cell activity was not adversely affected as CAR/CIR T cells robustly eliminated disease in leukemia-bearing NSG mice. Lastly, using an in vitro CRS assay, we sought to determine if attenuated CAR T cells would be less potent in activating myeloid cells. We observed that monocyte-derived macrophage and DC activation by CD19 CAR/CIR T cells was reduced as evidenced by decreased secretion of proinflammatory cytokines and chemokines. Conclusion These results provide a compelling proof of concept of a novel self-regulating CAR T cell design with the potential to mitigate severe toxicities in patients.

Stability Assessment of Fresh or Cryopreserved Whole Blood and Bone Marrow Samples from AML and B-ALL Patients to Monitor CD123 Receptor and Immune Cells Subsets

Introduction: Compounds targeting CD123 are currently under clinical development for the treatment of acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS). As part of clinical trials, CD123 expression and immune cell subsets need be monitored by quantitative flow cytometry (qFC) in bone marrow (BM) aspirates and whole blood (WB) samples before and on-treatment. One critical parameter for analysis is the poor stability of the fresh biological BM or WB samples. No general rule can predict the stability of the expression of a given receptor on diseased or healthy cells thus the pre-analytical stability of each biomarker should be evaluated to design the sample logistics. The pre analytical stability of clinical samples is the main constraint for quantitative flow cytometry (qFC) in multicenter and worldwide clinical studies. The transportation of the samples is one of the limiting factor. The classical freezing method of peripherical whole blood (WB) or bone marrow (BM) isolated by Ficoll requires high skilled operators, is time consuming and may be difficult to set up at sampling site in hospitals. One option to make the clinical samples suitable for subsequent high dimensional analysis by qFC is to use a simple freezing method at -80°C. Our cryopreservation method could be a new option for easier preparation of clinical samples prior to centralized samples analysis. This study aims to evaluate the pre-analytical fresh or cryopreserved stability of each pharmacodynamic monitoring endpoint over time: CD123 expression and receptor density, T-cell subsets and activation profile. Methods: FreshBM and WB were collected in EDTA tubes from 5 AML/MDS patients at hospitals, in accordance with local regulations. The samples were stored at room temperature (RT) for 4, 24, 48 or 72 h before immunostaining with the standard operation procedures and analysis by qFC or mixed with the cryopreserved media (BioCytex) within 24 h post-collection before freezing at -80°C for months. After storage, the cryopreserved samples were thawed and immunostained before analysis by qFC. Using a qFC assay (Multiplex FC panel assay developed by BioCytex, Marseille, France), CD123 receptor density/cell was collected. T-cell and blast cell immunophenotypes were also assessed on fresh samples for time point 4, 24, 48, or 72 h post-collection but also for cryopreserved WB sample within the 24hs post collection. The assay profiled blasts, monocytes, plasmacytoid dendritic cells, basophils and T-cells. Results: CD123 density in blast and normal cells was stable at RT from 4 h up to 48 h after collection. The profiles of blast subsets were very similar in BM and WB samples from a particular patient, whether a single blast cell subset (CD45lowCD11b-CD34+CD38med) or several blast cell subsets (expressing CD34 and CD38 at different levels) were identified. Both T-cell distribution and activation markers were stable up to 48 h for BM and WB. A similar pattern of T-cell subsets was also observed in the BM and WB paired samples from the same donor. In addition, CD123 receptor density, immunophenotyping and percentage of blast subsets and T cells from fresh WB samples was comparable to paired cryopreserved samples with a new method and for at least 1 month. Conclusions: Based on these observations, we conclude that CD123 density, blast cells and T-cell subsets in WB and BM samples from AML patients were stable for 48 h in our experimental conditions. As a consequence, fresh WB and BM samples can be processed and analyzed by qFC within 48 h of sample collection. Furthermore, the new cryopreservation method showed sample stabilization for blasts and T cells immunophenotyping. This data opens new perspectives in clinical studies for AML This new strategy would also help to standardize preparation of clinical samples and to centralize sample analysis.

IgG-antibodies to individual cytomegalovirus proteins and the peripheral blood lymphocyte subset profile in patients with anterior uveitis of varying severity

Background. Cytomegalovirus (CMV), a human beta-herpesvirus, persists latently lifelong after infection. CMV reactivation that occurs periodically can cause disease in target organs including the eye, not only in immunosuppressed, but also in immunocompetent people. Due to its immunosuppressive properties, persistent CMV is involved in the pathogenesis of diverse diseases. The aim was to study the features of antibody formation against six individual CMV proteins and to conduct a correlation analysis with parameters of peripheral blood lymphocyte profile in patients with anterior uveitis of varying severity (without hypopion-mild course, with hypopion-more severe course). Materials and methods. 36 patients with anterior uveitis were examined. Group I consisted of 20 patients without hypopion, group II 16 people with hypopion. No characteristic features of CMV anterior uveitis (elevated intraocular pressure, stromal iris atrophy) were found. Blood serum anti-CMV IgG antibodies (markers of chronic infection) were measured by ELISA, antibodies against individual recombinant CMV antigens were assessed by Line-Immunoassay specific to the main non-structural immediate early protein (IE), DNA-binding phosphoprotein p52, phosphoproteins of the tegument p150, p65, p28, GB-AD envelope glycoprotein. Lymphocyte subset composition was studied by flow cytometry: T-lymphocytes (CD3+), T-helper cells (CD3+CD4+CD8), T-cytotoxic (CD3+CD4CD8+), T-double-positive (CD3+CD4+CD8+), natural killers (CD16+CD56+), B-lymphocytes (CD19+). Statistical analysis was performed using StatTech v. 3.0.2 program (Stattech LLC, Russia). Results. In mild anterior uveitis, there was observed a significantly increased percentage of CD16+CD56+ and a decreased absolute number of CD3+CD8+ compared with anterior uveitis of a more severe course. Only in the group of patients with hypopion (more severe course) there was a direct significant correlation between level of antibodies against IE, p65, p28 antigens and percentage of double-positive cells (CD3+CD4+CD8+) as well as an negative significant relationship between the level of antibodies against IE, p65 and p52 antigens and CD19+ lymphocytes. Conclusion. The data obtained are consistent with few reports on the role of double-positive lymphocytes in the pathogenesis of severe forms of some viral diseases. Further studies are needed to assess an effect of individual viral antigens on CD3+CD4+CD8+ level in patients with chronic CMV infection to confirm the role of double-positive lymphocytes in the pathogenesis of a more severe course of anterior uveitis.

OS10.5.A PERIVASCULAR CONTAINED T CELLS IN IDH-MUTANT ASTROCYTOMA CO-LOCALIZE WITH GEMISTOCYTIC TUMOR CELLS OF AN ASTROCYTE-STATE AND MACROPHAGES WITH AN IMMUNE-STIMULATORY PHENOTYPE

Abstract BACKGROUND Isocitrate dehydrogenase mutant (IDHmt) astrocytoma is considered a T cell excluded tumor, yet little is known regarding the underlying cues that may drive T cell exclusion. To aid better understanding of this mechanism in IDHmt astrocytoma, we systematically characterized the immune microenvironment of this tumor type. METHODS We performed and analyzed multiplex immunofluorescence stainings for lymphocytes, myeloid cells and IDH1-R132H of 1293 regions from 75 IDHmt astrocytomas. We consequently performed bulk, single nucleus and spatial RNA sequencing of samples from the same cohort. Integrative analysis of data from these platforms allowed for the identification of unique tumor and immune cell subsets that are crucial in the spatial organization of the immune microenvironment and T cell containment in IDHmt astrocytoma. RESULTS IDHmt astrocytoma showed three spatially distinct distribution patterns of T cells: regions with perivascular accumulation of T cells, regions with T cells in the tumor stroma and T cell absent regions. Perivascular accumulation of T cells, known as T-cell cuffs, was the most abundant pattern in our data. Spatially, there was a significant increase of tumor cells around T cell cuffs that showed a gemistocytic phenotype, a tumor cell type that is histologically characterized by a large eosinophilic cytoplasm and ectopically localized nucleus. Gemistocyte-high tumors (&amp;gt; 20% of all tumor cells) demonstrated enhanced expression of genes related to immune cell migration and activation that were reliably expressed by tumor associated macrophages and T cells. Notably, gemistocytic tumor cells were identified as a distinct sub-cluster of the ‘astrocyte-like’ transcriptomic cell state with a phenotype that is linked to astrogliosis and expressed CD44, TNC and TGFB2. Moreover, gemistocytic tumor cells were spatially associated with a CD83+ subpopulation of tumor-associated macrophages that resemble reactive microglia in astrogliosis and show increased expression of the chemo-attractants CCL3, CCL4 and CCL4L2. CONCLUSION Using different modalities for spatial and single cell profiling of RNA and protein, we uncovered a previously unknown relationship between the immune system and tumor cells in IDHmt astrocytoma. We found that gemistocytic tumor cells showing an ‘astrocyte-like’ state co-occur with perivascular contained T cells and immune-stimulatory macrophages in IDHmt astrocytomas. The transcriptional profiles of these tumor cell subsets and macrophages point towards a CNS specific defense mechanism of glial cells associated with T cell exclusion.

Evaluation of Hematological Profiles and Monocyte Subpopulations in Water Buffalo Calves after Immunization with Two Different IBR Marker Vaccines and Subsequent Infection with Bubaline alphaherpesvirus-1.

Bubaline alphaherpesvirus-1 (BuAHV-1) and Bovine alphaherpesvirus-1 (BoAHV-1) are respiratory viruses that can cause an infection known as "Infectious Bovine Rhinotracheitis" (IBR) in both water buffalo and bovine species. As the main disease control strategy, vaccination can protect animals from clinical disease through the development of specific humoral and cell-mediated immune responses. In the present study, the time-related circulatory kinetics of hematological profile and bubaline monocyte subsets have been investigated in vaccinated buffalo calves after challenge infections with BuAHV-1. Thirteen buffalo calves were selected and grouped into the VAX-1 group, which received an IBR-live-attenuated gE-/tk-deleted marker vaccine; the VAX-2 group, which received an IBR-inactivated gE-deleted marker vaccine; the CNT group, which remained an unvaccinated control. Fifty-five days after the first vaccination, the animals were infected with 5 × 105.00 TCID50/mL of wild-type BuAHV-1 strain via the intranasal route. Whole blood samples were collected at 0, 2, 4, 7, 10, 15, 30, and 63 days post-challenge (PCDs) for the analysis of hematological profiles and the enumeration of monocyte subsets via flow cytometry. The analysis of leukocyte compositions revealed that neutrophils were the main leukocyte population, with a relative increase during the acute infection. On the other hand, a general decrease in the proportion of lymphocytes was observed early in the post-infection, both for the VAX-1 and VAX-2 groups, while in the CNT group, the decrease was observed later at +30 and +63 PCDs. An overall infection-induced increase in blood total monocytes was observed in all groups. The rise was especially marked in the animals vaccinated with an IBR-live-attenuated gE-/tK-deleted marker vaccine (VAX-1 group). A multicolor flow cytometry panel was used to identify the bubaline monocyte subpopulations (classical = cM; intermediate = intM; and non-classical = ncM) and to investigate their variations during BuAHV-1 infection. Our results showed an early increase in cMs followed by a second wave of intMs. This increase was observed mainly after stimulation with live-attenuated viruses in the VAX-1 group compared with the animals vaccinated with the inactivated vaccine or the non-vaccinated animal group. In summary, the present study characterized, for the first time, the hematological profile and distribution of blood monocyte subsets in vaccinated and non-vaccinated water buffalo in response to experimental infection with BuAHV-1. Although not experimentally proven, our results support the hypothesis of a linear developmental relationship between monocyte subsets.