Analysis Of Immune Cell Subsets Research Articles

Mass cytometric single cell immune profiles of peripheral blood from acute myeloid leukemia patients in complete remission with measurable residual disease.

Measurable residual disease (MRD) is detected in approximately a quarter of AML chemotherapy responders, serving as a predictor for relapse and shorter survival. Immunological control of residual disease is suggested to prevent relapse, but the mechanisms involved are not fully understood. We present a peripheral blood single cell immune profiling by mass cytometry using a 42-antibody panel with particular emphasis on markers of cellular immune response. Six healthy donors were compared with four AML patients with MRD (MRD+) in first complete remission (CR1MRD+). Three of four patients demonstrated a favorable genetic risk profile, while the fourth patient had an unfavorable risk profile (complex karyotype, TP53-mutation) and a high level of MRD. Unsupervised clustering using self-organizing maps and dimensional reduction analysis was performed for visualization and analysis of immune cell subsets. CD57+ natural killer (NK)-cell subsets were found to be less abundant in patients than in healthy donors. Both T and NK cells demonstrated elevated expression of activity and maturation markers (CD44, granzyme B, and phosho-STAT5 Y694) in patients. Although mass cytometry remains an expensive method with limited scalability, our data suggest the utility for employing a 42-plex profiling for cellular immune surveillance in whole blood, and possibly as a biomarker platform in future clinical trials. The findings encourage further investigations of single cell immune profiling in CR1MRD+ AML-patients.

Biomarker analysis of zanzalintinib in clear cell renal cell carcinoma from STELLAR-001.

4545 Background: Zanzalintinib (zanza) is a novel oral multi-targeted TKI that inhibits several receptors, including VEGFR, MET, and TAM kinases. In an expansion cohort of previously treated patients (pts) with clear cell renal cell carcinoma (ccRCC) from the phase 1b STELLAR-001 study (NCT03845166), single-agent zanza showed encouraging activity (ORR, 38%; disease control rate, 88%), with responses seen in VEGFR TKI–pretreated pts, and a manageable safety profile (Pal, IKCS NA 2023:Abs 1). Here, we investigate biomarkers associated with zanza from the STELLAR-001 ccRCC expansion cohort. Methods: Adult pts (N=32) with advanced ccRCC, ECOG ≤1, and 1–3 prior systemic anticancer therapies received zanza 100 mg once daily until unacceptable toxicity or no longer deriving clinical benefit. Circulating plasma biomarkers and immune cell populations in blood were assessed at baseline and on-study. IHC for AXL, c-Met, phosphorylated Met, and VEGFR2 was performed on archival tissue. Associations between response to zanza and biomarker levels (at baseline and treatment-related changes) were investigated by comparing zanza responders (CR/PR; n=10) and non-responders (SD/PD; n=19). The relation between baseline biomarker levels and prior exposure to VEGFR TKI was also evaluated. P values were determined using a Wilcoxon test ( P<0.05 considered significant). Results: Zanza elicited significant changes in soluble biomarkers related to angiogenesis, tumor growth and metastasis, and immune modulation, including an increase in the circulating ligands VEGF ( P<0.001) and GAS6 ( P<0.001); decreases in ANG-1 ( P<0.001) and ANG-2 ( P<0.001), and the soluble angiogenic receptors, VEGFR2 ( P<0.001) and TIE-2 ( P<0.001). A decrease in levels of the chemokine, RANTES ( P<0.001), and an increase in IFNγ ( P=0.039) and the pro-apoptotic protein, granzyme B ( P<0.001) were also observed. An analysis of immune cell subsets showed that zanza raised activated cytotoxic T cell numbers ( P=0.002). Reductions in monocytes ( P=0.001), along with immunosuppressive subsets (total MDSCs [ P=0.013] and granulocytic MDSCs [ P=0.014]) were also observed. Response to zanza was associated with lower baseline levels of plasma biomarkers including CRP ( P=0.025) and HGF ( P=0.017), but not with any tissue biomarkers or zanza-mediated changes in immune cells or plasma biomarkers tested. Lower baseline levels of VEGFR2 were observed in pts with prior VEGFR TKI exposure ( P=0.042). Conclusions: Zanza in pts with advanced ccRCC leads to modulation of plasma biomarkers associated with angiogenesis and peripheral immune cell subsets consistent with its expected mechanism of action. The reduction in immunosuppressive immune cells and activation of effector immune cells by zanza support the rationale for combining zanza with immune checkpoint inhibitors. Given the small sample sizes, further investigation in larger studies is warranted. Clinical trial information: NCT03845166 .

Analysis of Immune Cell Subsets in Peripheral Blood from Patients with Engineered Stone Silica-Induced Lung Inflammation.

Silicosis caused by engineered stone (ES-silicosis) is an emerging worldwide issue characterized by inflammation and fibrosis in the lungs. To our knowledge, only a few reports have investigated leukocyte/lymphocyte subsets in ES-silicosis patients. The present study was designed to explore the proportions of the main lymphocyte subsets in ES-silicosis patients stratified into two groups, one with simple silicosis (SS) and the other with a more advanced state of the disease, defined as progressive massive fibrosis (PMF). The proportions of B (memory and plasmablasts) cells, T (helper, cytotoxic, regulatory) cells, and natural killer (NK) (regulatory and cytotoxic) cells were investigated by multiparameter flow cytometry in 91 ES-silicosis patients (53 SS patients and 38 PMF patients) and 22 healthy controls (HC). Although the total number of leukocytes did not differ between the groups studied, lymphopenia was observed in patients compared to healthy controls. Compared with those in healthy controls, the proportions of memory B cells, naïve helper T cells, and the CD4+/CD8+ T cells' ratio in the peripheral blood of patients with silicosis were significantly decreased, while the percentages of plasma cells, memory helper T cells, and regulatory T cells were significantly increased. For the NK cell subsets, no significant differences were found between the groups studied. These results revealed altered cellular immune processes in the peripheral blood of patients with ES-silicosis and provided further insight into silicosis pathogenesis.

Bortezomib restrains M2 polarization and reduces CXCL16-associated CXCR6+CD4 T cell chemotaxis in bleomycin-induced pulmonary fibrosis

BackgroundThe development of pulmonary fibrosis involves a cascade of events, in which inflammation mediated by immune cells plays a pivotal role. Chemotherapeutic drugs have been shown to have dual effects on fibrosis, with bleomycin exacerbating pulmonary fibrosis and bortezomib alleviating tissue fibrotic processes. Understanding the intricate interplay between chemotherapeutic drugs, immune responses, and pulmonary fibrosis is likely to serve as the foundation for crafting tailored therapeutic strategies.MethodsA model of bleomycin-induced pulmonary fibrosis was established, followed by treatment with bortezomib. Tissue samples were collected for analysis of immune cell subsets and functional assessment by flow cytometry and in vitro cell experiments. Additionally, multi-omics analysis was conducted to further elucidate the expression of chemokines and chemokine receptors, as well as the characteristics of cell populations.ResultsHere, we observed that the expression of CXCL16 and CXCR6 was elevated in the lung tissue of a pulmonary fibrosis model. In the context of pulmonary fibrosis or TGF-β1 stimulation in vitro, macrophages exhibited an M2-polarized phenotype and secreted more CXCL16 than those of the control group. Moreover, flow cytometry revealed increased expression levels of CD69 and CXCR6 in pulmonary CD4 T cells during fibrosis progression. The administration of bortezomib alleviated bleomycin-induced pulmonary fibrosis, accompanied by reduced ratio of M2-polarized macrophages and decreased accumulation of CD4 T cells expressing CXCR6.ConclusionsOur findings provide insights into the key immune players involved in bleomycin-induced pulmonary fibrosis and offer preclinical evidence supporting the repurposing strategy and combination approaches to reduce lung fibrosis.

Exploratory mass cytometry analysis reveals immunophenotypes of cancer treatment-related pneumonitis.

Anticancer treatments can result in various adverse effects, including infections due to immune suppression/dysregulation and drug-induced toxicity in the lung. One of the major opportunistic infections is Pneumocystis jirovecii pneumonia (PCP), which can cause severe respiratory complications and high mortality rates. Cytotoxic drugs and immune-checkpoint inhibitors (ICIs) can induce interstitial lung diseases (ILDs). Nonetheless, the differentiation of these diseases can be difficult, and the pathogenic mechanisms of such diseases are not yet fully understood. To better comprehend the immunophenotypes, we conducted an exploratory mass cytometry analysis of immune cell subsets in bronchoalveolar lavage fluid from patients with PCP, cytotoxic drug-induced ILD (DI-ILD), and ICI-associated ILD (ICI-ILD) using two panels containing 64 markers. In PCP, we observed an expansion of the CD16+ T cell population, with the highest CD16+ T proportion in a fatal case. In ICI-ILD, we found an increase in CD57+ CD8+ T cells expressing immune checkpoints (TIGIT+ LAG3+ TIM-3+ PD-1+), FCRL5+ B cells, and CCR2+ CCR5+ CD14+ monocytes. These findings uncover the diverse immunophenotypes and possible pathomechanisms of cancer treatment-related pneumonitis.

Exploratory mass cytometry analysis reveals immunophenotypes of cancer treatment-related pneumonitis

Anticancer treatments can result in various adverse effects, including infections due to immune suppression/dysregulation and drug-induced toxicity in the lung. One of the major opportunistic infections is Pneumocystis jirovecii pneumonia (PCP), which can cause severe respiratory complications and high mortality rates. Cytotoxic drugs and immune-checkpoint inhibitors (ICIs) can induce interstitial lung diseases (ILDs). Nonetheless, the differentiation of these diseases can be difficult, and the pathogenic mechanisms of such diseases are not yet fully understood. To better comprehend the immunophenotypes, we conducted an exploratory mass cytometry analysis of immune cell subsets in bronchoalveolar lavage fluid from patients with PCP, cytotoxic drug-induced ILD (DI-ILD), and ICI-associated ILD (ICI-ILD) using two panels containing 64 markers. In PCP, we observed an expansion of the CD16+ T cell population, with the highest CD16+ T proportion in a fatal case. In ICI-ILD, we found an increase in CD57+ CD8+ T cells expressing immune checkpoints (TIGIT+ LAG3+ TIM-3+ PD-1+), FCRL5+ B cells, and CCR2+ CCR5+ CD14+ monocytes. These findings uncover the diverse immunophenotypes and possible pathomechanisms of cancer treatment-related pneumonitis.

Abstract P25: Identification of biological components and novel clinical subsets of NPM1-mutated AML using an integrated, multi-omics approach

Abstract P25: Identification of biological components and novel clinical subsets of <i>NPM1</i>-mutated AML using an integrated, multi-omics approach

Anti-Inflammatory Effects of a Novel Nuclear Factor-κB Inhibitory Derivative Derived from Pyrazolo[3,4-d]Pyrimidine in Three Inflammation Models.

Nuclear factor-κB (NF-κB) plays a central role in inflammatory responses, and its physiologic functions are essential for cell survival and proliferation. Currently, drugs targeting NF-κB inhibition have not yet been applied in clinical practice. We investigated the physiologic effect of a novel NF-κB inhibitory compound, 1H-pyrazolo[3,4-d]pyrimidin-4-amine derivative (INH #1), on three inflammatory animal models. The pharmacokinetics were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Acute hepatitis was induced by administrating lipopolysaccharide (LPS) and D-(+)-galactosamine hydrochloride followed by the analysis of survival time and inflammatory mediators. Collagen-induced arthritis (CIA) was induced by immunization with type II collagen (CII), and serum-transfer arthritis (STA) was caused by injecting K/BxN mice serum. Clinical and histologic scores were evaluated in both arthritis models. Immune cell subset analysis, CII-induced interferon-gamma (IFN-γ) production and proliferation, and measurement of anti-CII IgG antibodies were performed in the CIA model. In the acute hepatitis model, INH #1 suppressed tumor necrosis factor-α (TNF-α) production and prevented early death in a dose-dependent manner. INH #1 significantly attenuated arthritis scores and joint inflammation in both arthritis models. Additionally, in the CIA model, dendritic cells (DCs) in the regional lymph nodes were decreased in the treated mice and antigen-induced IFN-γ production and cell proliferation in splenocytes were inhibited, whereas the titers of anti-CII IgG antibodies were comparable regardless of the treatment. Here we revealed that INH #1 exerted anti-inflammatory effects in vivo via inhibition of inflammatory mediators and suppression of cellular immune responses. This compound could be a novel candidate for inhibition of NF-κB in certain inflammatory diseases. SIGNIFICANCE STATEMENT: A novel nuclear factor-κB (NF-κB) inhibitory compound, 1H-pyrazolo[3,4-d]pyrimidin-4-amine derivative (INH #1), which retains physiologically essential NF-κB bioactivity, suppressed inflammation in three different mouse models: the acute hepatitis model, the collagen-induced arthritis model, and the K/BxN serum-transfer arthritis model. These results suggest that this compound could be a novel and potent anti-inflammatory agent.

Investigating the complex interplay between fibroblast activation protein α-positive cancer associated fibroblasts and the tumor microenvironment in the context of cancer immunotherapy.

This study investigates the role of Fibroblast Activation Protein (FAP)-positive cancer-associated fibroblasts (FAP+CAF) in shaping the tumor immune microenvironment, focusing on its association with immune cell functionality and cytokine expression patterns. Utilizing immunohistochemistry, we observed elevated FAP+CAF density in metastatic versus primary renal cell carcinoma (RCC) tumors, with higher FAP+CAF correlating with increased T cell infiltration in RCC, a unique phenomenon illustrating the complex interplay between tumor progression, FAP+CAF density, and immune response. Analysis of immune cell subsets in FAP+CAF-rich stromal areas further revealed significant correlations between FAP+ stroma and various T cell types, particularly in RCC and non-small cell lung cancer (NSCLC). This was complemented by transcriptomic analyses, expanding the range of stromal and immune cell subsets interrogated, as well as to additional tumor types. This enabled evaluating the association of these subsets with tumor infiltration, tumor vascularization and other components of the tumor microenvironment. Our comprehensive study also encompassed cytokine, angiogenesis, and inflammation gene signatures across different cancer types, revealing heterogeneous cellular composition, cytokine expressions and angiogenic profiles. Through cytokine pathway profiling, we explored the relationship between FAP+CAF density and immune cell states, uncovering potential immunosuppressive circuits that limit anti-tumor activity in tumor-resident immune cells. These findings underscore the complexity of tumor biology and the necessity for personalized therapeutic and patient enrichment approaches. The insights gathered from FAP+CAF prevalence, immune infiltration, and gene signatures provide valuable perspectives on tumor microenvironments, aiding in future research and clinical strategy development.

Gansui Banxia decoction modulates immune-inflammatory homeostasis to ameliorate malignant ascites in rats

Background“Gansui Banxia decoction” (GBD) is a classical traditional Chinese medicine formula for treating abnormal accumulation of fluid, such as malignant ascites (MA). Although GBD has shown definite water-expelling effects, its exact underlying mechanism has not been elucidated. PurposeThis study aimed to investigate the drug effects of GBD on MA rats and its underlying mechanisms. MethodsThe main chemical composition was determined by ultra-high performance liquid chromatography. The drug effects of GBD was evaluated in the established cancer cell-induced MA rat model. The symptoms were analyzed, and biological samples were collected for detecting immune and inflammation-related indicators by enzyme-linked immunosorbent assays, western blot, and flow cytometry. ResultsGBD increased urine discharge, decreased ascites production, and alleviated cachexia. After GBD treatment, the expression of TLR4, MyD88, and NF-кB and the release of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were reduced. In addition, GBD increased G1 phase arrest and inhibit excessive proliferation of cells in bone marrow while alleviating G1 phase arrest and increasing proliferation of cells in the thymus. Correspondingly, the development and maturation of T cells also changed. GBD increased the proportion of mature T-cells (CD4+CD8− and CD4−CD8+ single-positive (SP) T-cells), and decrease the proportion of immature cells (CD4+CD8+ double-positive (DP) T-cells and CD4−CD8− double-negative (DN) T-cells) in the blood or tumor microenvironment (TME, the ascites microenvironment). Finally, we further analysis of immune cell subsets, GBD decreased the proportion of immunosuppressive T-cells in the blood (CD4+CD25+Foxp3+T-cells) and TME (CD8+CD25+Foxp3+T-cells), and increased the proportion of anti-tumor immune cells (CD8+CD28+T-cells and NK cells) in the TME. ConclusionThese findings indicated that the drug effects of GBD were attributed to regulating the immune-inflammatory homeostasis, thereby mitigating the destruction of cancer cells and reducing the generation of ascites, which provided theoretical support for the clinical rational application and extended the scientific connotation of “water-expelling” of GBD.

The consensus of Chinese experts on refined analysis of immune cell subsets in peripheral blood by multi-parameter flow cytometry

The detection of immune cell subsets plays a very important role in the clinical diagnosis and treatment of various benign and malignant diseases and health management. In order to better carry out in-depth research on different functional immune cell subsets, establish reference intervals for clonality related indicators, establish special reference intervals for immune aging, individualized dynamic monitoring and treatment recovery, and discover the clinical significance of immune cells other than lymphocytes, it is urgent to analyze the peripheral blood immune cell subsets in a refined way. Multiparameter flow cytometry is an important technical method to detect immune cell subsets and evaluate immune function. In order to standardize the refined detection methods and protocols of peripheral blood immune cell subsets by flow cytometry, and further promote its application in clinical diagnosis and treatment of diseases and health management, Laboratory Medicine Committee of Chinese Association of Integrative Medicine (LMC-CAIM) organized experts to formulate this expert consensus.

Donor T Cell Infusions Limit Novel Immune Checkpoint Therapy in Pancreatic Cancer: Implications for Adoptive T Cell Therapy

Background: We have previously published that pancreatic cancers over-express an immunosuppressive peptide, vasoactive intestinal polypeptide (VIP), and that a novel combination of antin-PD1 antibodies and small molecule antagonists to the VIP receptor can induce complete remission of pancreatic ductal adenocarcinoma (PDAC) in multiple mouse models (Ravibndranathan, Nat. Comm. 2022). To enhance the efficacy of this novel immunotherapy approach, we hypothesized that infusions of additional donor T cells to PDAC-bearing mice receiving the combination of anti-PD1/VIP receptor antagonists would lead to more intra-tumoral effector T cells and increased tumor regression rates. To investigate the potential impact of adoptive splenocyte infusion on checkpoint immunotherapy, we established sub-cutaneous KPC PDAC tumors in C57Bl/6 mice. As previously described, we treated them with a combination of ANT308 (VIP-receptor antagonists) and anti-PD1. We tested whether adding splenocyte infusions from donor mice that were immunologically naïve or donor mice previously engrafted with PDAC with regressed (positive control) or progressed tumors (negative control) would enhance the efficacy of the immune checkpoint blockade therapy. Methods: C57BL/6 B6 CD45.1 recipient mice were inoculated subcutaneously with 1 x 10 6 KPC-luc PDAC cell line cells on day -5. Recipient mice received anti-PD1 (200mg) every three days (totaling four doses) and 21 daily s.c. injections of 20 ug ANT308. Splenocytes from three groups of CD45.2+ C57BL/6 donor mice were injected into tumor-bearing recipients: naive mice, mice with a history of KPC regression post-ANT308/anti-PD1 treatment, and mice with progressed KPC tumors without any treatment. Anti-PD1 and ANT308 treatments were initiated simultaneously with adoptive splenocyte infusion (25 x 10 6 cells) on day 0. Tumor size was measured biweekly, and IVIS imaging was performed weekly. Blood was drawn weekly from recipient mice for flow cytometric analysis of immune cell subsets. A fraction of tumor-bearing recipient mice was euthanized ten days after donor splenocyte infusion and initiation of immune checkpoint therapy or at IAUCAC-defined endpoints. When tumor-bearing mice were euthanized, the spleen, lymph nodes, and tumors were harvested for further flow cytometric analysis. The remaining mice were monitored for tumor growth and survival kinetics. Results: Contrary to our original hypothesis, we observed substantially lower survival rates and faster tumor growth in the group that received splenocytes from immunologically naive donor mice versus the group treated with splenocytes from tumor-bearing mice (Figures 1A and 1B). Splenocytes from immunologically naive donors contained fewer Treg cells, whereas myeloid-derived suppressor cells (CD11b+Ly-6G+ Gr-1+) were increased in donor splenocytes from tumor-bearing mice. We next repeated the experiment utilizing the adoptive transfer of splenocytes from immunologically naïve donors separated into 8 x 10 6 MACS-purified T cell or 17 x 10 6 non-T cell fractions. Remarkably, the transfer of 8 x 10 6 immunologically naïve T cells abrogated the efficacy of immune checkpoint therapy leading to rapid tumor growth compared to tumor regression in mice treated with immune checkpoint therapy without added donor splenocytes or mice that received immune checkpoint therapy with 17 x 10 6 T-cell-depleted donor splenocytes. Flow cytometric and gene expression analyses of splenocytes from the recipient mice, and those not receiving donor T cell infusions, revealed that the tetramer population in the infusion group was significantly higher than in the group treated only with immune checkpoint inhibitors. Conclusion: Our findings indicated that natural suppressor/ Treg in immunologically naïve splenocytes could exert a profound negative regulatory effect on immune checkpoint therapy's efficacy in a murine PDAC model. Despite having fewer Treg than splenocytes from tumor-bearing donors, immunologically naïve natural Treg had increased potency in suppressing anti-cancer immunity. These findings suggest the importance of the depletion of natural Treg in adoptive cell therapy strategies to treat solid tumor malignancies. This research underscores the critical role of immune contexture in shaping therapeutic outcomes and proposes a novel biomarker for patient stratification in PDAC immunotherapy.

Povetacicept (ALPN-303), a Potent Dual BAFF/APRIL Antagonist in Development for the Treatment of Autoimmune Cytopenias, Suppresses Disease in a Mouse Model of Autoimmune Hemolytic Anemia

Introduction: B cell activating factor (BAFF) and a proliferation inducing ligand (APRIL) play key roles in B cell development, survival, and differentiation into antibody-secreting cells (ASC). Given their importance in ASC survival and antibody production, inhibition of BAFF and/or APRIL (particularly in combination) is a promising approach for the treatment of a variety of autoimmune or autoantibody-related diseases including autoimmune cytopenias like warm autoimmune hemolytic anemia (wAIHA), immune thrombocytopenia (ITP), and cold agglutinin disease (CAD). Significantly higher levels of both BAFF and APRIL have been observed in the serum of patients with AIHA and ITP compared to healthy subjects, and polymorphisms in BAFF and TACI have been associated with ITP [Abdel-Hamid et al., Am J Med, 2011; Xu et al., Int J Hematol., 2015; Emmerich, et al., Br J Haematol, 2007; Peng, et al., J Thromb Haemost, 2017; Yu, et al., Blood Adv, 2021]. Belimumab, an anti-BAFF antibody, has demonstrated encouraging efficacy in the treatment of ITP associated with systemic lupus erythematosus [De Marchi, et al., Clin Exp Rheumatol, 2017] and in combination with rituximab in patients with ITP [Mahévas, et al., Haematologica, 2021]. Currently, there are no BAFF and/or APRIL inhibitors approved to treat AIHA or ITP. Povetacicept (ALPN-303) is an engineered, potent dual BAFF/APRIL antagonist. We previously evaluated the impact of BAFF/APRIL co-inhibition preclinically in the accelerated HODxOTII transgenic mouse model of AIHA, in which povetacicept treatment significantly suppressed plasma cells in the spleen and bone marrow, reduced pathogenic anti-RBC autoantibodies, and significantly increased hematocrit [Dillon et al., ASH 2022 abstract #3763]. Here, we have evaluated povetacicept in a second preclinical model of AIHA, a rat red blood cell (RRBC)-to-mouse model of erythrocyte autoimmunity. Methods: In the RRBC model, C57BL/6NJ mice were immunized weekly with 2 x 10 8 Wistar rat RBC for 10 weeks, leading to development of anti-mouse RBC autoantibodies. Groups of mice were treated twice weekly via intraperitoneal injection with povetacicept or a matched Fc isotype control. Analyses included anti-RRBC alloantibodies and autoantibodies bound to mouse erythrocytes (measured via direct anti-globulin test [DAT]). While significant anemia does not occur in this model, serum lactate dehydrogenase (LDH) was also measured as an index measure of subclinical hemolysis. Immune cell subset analysis of splenocytes by flow cytometry was also performed. Results: As compared to Fc control, povetacicept treatment significantly reduced levels of anti-RRBC and DAT of IgM and IgG isotypes and significantly limited serum LDH elevations at various timepoints during the study ( Figure 1). Furthermore, at 10 weeks, numbers of T follicular helper (Tfh) cells, total B cells, germinal center (GC) B cells, and plasma cells were significantly lower in spleens of povetacicept-treated mice ( Figure 2). Conclusions: Povetacicept effectively reduced pathogenic autoantibodies and key B cell populations (e.g., ASC) and limited serum LDH elevations in this mouse model of erythrocyte autoimmunity. These data suggest that povetacicept may reduce multiple pathogenic inflammatory processes including autoantibody production and may be an effective treatment for AIHA and other autoimmune cytopenias. Povetacicept is currently being evaluated in an open-label study (RUBY-4; NCT05757570) of adults with autoimmune cytopenias (ITP, AIHA, and CAD).

SAT297 Major Immunophenotypic Abnormalities In Patients With Primary Adrenal Insufficiency Of Different Etiology

Abstract Disclosure: H.F. Nowotny: None. T. Marchant Seiter: None. J. Ju: None. A. Gottschlich: None. H. Schneider: None. S. Zopp: None. F. Vogel: None. L. Tschaidse: None. M.K. Auer: None. C. Lottspeich: None. S. Kobold: None. S. Rothenfusser: None. F. Beuschlein: None. M. Reincke: None. L. Braun: None. N. Reisch: None. Background: Increased risk of infection, adrenal crises and a higher mortality rate have been reported for patients with primary adrenal insufficiency (PAI). Such dismal outcomes have been inferred to immune cell dysregulation as a consequence of unphysiological cortisol replacement. As the immune landscape of patients with different types of PAI has not been systematically explored, we set out to immunophenotype PAI patients with different causes of glucocorticoid deficiency. Methods: The present cross-sectional single center study includes 28 patients with congenital adrenal hyperplasia (CAH), 27 patients after bilateral adrenalectomy due to Cushing’s syndrome (BADx), 21 patients with Addison’s disease (AD) and 52 healthy controls. All patients with PAI were on a stable glucocorticoid replacement regimen using a median dose of 25 mg hydrocortisone (IQR 5 mg for BADx and AD and IQR 10 mg for CAH) per day. Heparinized blood samples were processed to isolate peripheral blood mononuclear cells. All samples were processed for analysis of immune cell subsets using multicolor flow cytometry after four-hour stimulation with phorbol myristate acetate (PMA)/Ionomycin, as well as analysis of natural killer (NK-) cell cytotoxicity and clock gene expression. Results: Analysis of immune cell profiles revealed reduced percentages of IFNγ-secreting T helper (Th1) in AD (p = 0.0024) and cytotoxic (Tc1) cells in CAH (p = 0.0055) and AD patients (p = 0.0075) compared to controls. Moreover, we observed a downregulation of the percentage of IL-4+ Th2 cells in AD patients (p = 0.0157) and Tc2 cells in AD (p = 0.0154) and CAH patients (p = 0.0012) compared to controls. Th17 and Tc17 cells were also downregulated in patients with AD compared to the other patient groups and controls (p &amp;lt; 0.0001). NK-cell cytotoxicity (NKCC) using bioluminescence measurements was reduced in all subsets of PAI patients compared to controls with the lowest change in patients with CAH (mean specific lysis 57.5% in controls, 21.7% in CAH, -0.5% in AD and -28.7% in BADx). The percentage of activated NK-cells was upregulated in BADx (p = 0.0008) and AD patients (p = 0.0348) compared to controls, also expressed as an increase in CD107a expression as a marker of NK-cell degranulation (BADx p &amp;lt; 0.0001; AD p = 0.0002). While the percentage of NK-cell activating receptor expressing NK-cells did not differ from controls, expression percentage of NK-cell inhibiting receptor CD94 was upregulated in both BADx and AD patients (p &amp;lt; 0.0001). Conclusion: In patients with three different etiologies of PAI, distinct differences in T- and NK-cell-phenotypes became apparent despite the use of same GC preparation and dose. Our results highlight so far unsuspected differences in immune cell composition and NK-cell function in PAI patients of different causes and suggest disease-specific alterations that might necessitate disease-specific treatment. Presentation: Saturday, June 17, 2023

The transcription factor T-bet promotes the pathogenesis of nonalcoholic fatty liver disease by upregulating intrahepatic inflammation

ObjectiveTo investigate the effect of the transcription factor T-bet on the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and the regulation of the intrahepatic immune microenvironment. MethodsWild-type and T-bet knockout NASH mouse models were constructed. The effect of T-bet knockout on the pathogenesis of NAFLD was observed by histochemical staining. The expression of T-bet in immune cells in the liver and the effect of T-bet knockout on the proportion and function of immune cell subsets in the liver were determined by flow analysis. ResultsFlow cytometry results indicated that T-bet expression was increased in immune cells, especially NKT cells, in the livers of NAFLD mice. Knocking out the transcription factor T-bet reduced intrahepatic inflammation, reduced lipid accumulation, and ameliorated the pathogenesis of NAFLD. Based on the analysis of immune cell subsets, knocking out the transcription factor T-bet decreased the proportion, survival, and degree of activation of NK, NKT, and CD8 T cells in NAFLD liver; additionally, it decreased the secretion of IFN-γ by T cells and NKT cells but had no effect on the proportion of Th17 cells and Treg cells. Knocking out the transcription factor T-bet also reduced the proportion of proinflammatory myeloid-derived macrophages (MoMFs) in NAFLD liver, mainly the proportion of proinflammatory Ly6Chigh MoMFs. Furthermore, knocking out the transcription factor T-bet had no significant effect on the secretion of TNF-α from MoMFs but significantly reduced the expression of MHC class II molecules. Further analysis showed that the transcription factor T-bet may directly affect the expression of MHC class II molecules H2-AB1 and H2-Dmb1 through transcriptional regulation. ConclusionsKnocking out the transcription factor T-bet reduced the proinflammatory effect of innate immune cells (MoMFs, NK cells, and NKT cells) and T lymphocytes in NAFLD liver, thereby reducing intrahepatic inflammation and delaying the pathogenesis of NAFLD.

SYST-08 ROLE OF THE MICROBIOME IN BRAIN TUMORS

Abstract A cross-sectional study was conducted to investigate the potential role of the microbiome in brain tumors. The study included 50 patients with histologically confirmed brain tumors and 50 healthy controls matched for age and gender. Fecal samples were collected from all participants and analyzed for bacterial composition using 16S rRNA gene sequencing. The results showed significant differences in the composition of the microbiome between the brain tumor patients and healthy controls. Specifically, patients with brain tumors had a higher abundance of certain bacterial species, including Fusobacterium and Porphyromonas, compared to the healthy controls. These bacterial species have previously been associated with inflammation and have been implicated in the development and progression of various types of cancer. Furthermore, the study investigated the potential interaction between the microbiome and the immune system in the context of brain tumors. Analysis of immune cell subsets in peripheral blood samples revealed differences between the brain tumor patients and healthy controls, with the tumor patients showing a lower proportion of CD8+ T cells and a higher proportion of regulatory T cells. Interestingly, there was also a correlation between the abundance of certain bacterial species and the proportion of immune cells, suggesting a potential role for the microbiome in modulating immune function in brain tumors. These findings suggest that the microbiome may play a role in the development and progression of brain tumors. Further studies are needed to investigate the mechanisms underlying this association and to determine whether interventions targeting the microbiome could have therapeutic benefit in brain tumors.

NEUROINFLAMMATION AND IMMUNE DYSFUNCTION IN THE PATHOGENESIS OF PARKINSON’S DISEASE

Parkinson’s disease (PD) is a chronic progressive neurodegenerative disorder, characterized by dopaminergic neuronal loss, aggregation of alpha-synuclein and severe motor impairments. This review summarizes current data on the key role of neuroinflammation and immune dysfunction in neurodegeneration and disease development. We examine clinical and experimental evidence for microglia activation, participation of Toll-like receptors in this process, a wide range of chemokines and pro- and anti-inflammatory cytokines in the course of the disease. Emphasis is also made on the impact of the innate and adaptive immune responses in the mechanisms of systemic inflammation both in the brain and in the periphery. The involvement of brain-infiltrating immune cells and their subpopulations in the process of neuroinflammation and neurodegeneration, changes in the composition and phenotype of peripheral immune cells and their functional characteristics are discussed. Analysis of immune cell subsets and their ratios reveals subtle PD-specific changes in cellular populations that can be used as reliable biomarkers for diagnosis, prognosis of the disease course, and development of new approaches for anti-inflammatory and targeted therapies in PD.

Combinatory analysis of immune cell subsets and tumor-specific genetic variants can predict clinical response to PD-1 blockade for non-small cell lung cancer patients

Abstract Blockade of PD-1/PDL1 (PD-1 blockade) with antibodies has revolutionized treatment options for non-small cell lung cancer (NSCLC) patients with tumors without targetable mutations. The benefit of PD-1 blockade is limited only to a subset of the patients. This study aims to identify biological markers of clinical response in a discovery cohort (n=15) of patients early during treatment to distinguish responders from nonresponders using immunological and genetic markers. Immune subsets identified in the blood are characterized to establish a panel of immune markers that could distinguish the two. Blood drawn from NSCLC patients before and after PD-1 blockade was analyzed by clinical flow cytometric assay for changes in the frequencies and concentration of immune cell populations. Next generation sequencing was performed on the extracted DNA from archival tumor biopsies from the same patients. irRECIST criteria was used to evaluate the clinical responses with cut-off at 10 months. Responders had a significantly increased frequency of activated effector memory CD4 &amp; CD8 T cells &amp; decreased frequency of central memory CD4 &amp; CD8 T cells in circulation post-treatment compared to pre-treatment. In a separate cohort we validate initial findings in a cohort of n=29 &amp; observe that effector memory CD8 T cells in responders produced high TNFα at pretreatment. Pathogenic &amp; likely-pathogenic mutations in TP53, KRAS, KEAP1, NOTCH-1 and STK11 in the patients that responded to PD-1 blockade are observed. A multivariate analysis combining immune and genetic parameters could discriminate responders from non-responders. We report that combined analyses of selected immune cell &amp; genetic parameters could predict early clinical response to PD-1 blockade.

Manual cell selection in single cell transcriptomics using scSELpy supports the analysis of immune cell subsets.

Single cell RNA sequencing plays an increasing and indispensable role in immunological research such as in the field of inflammatory bowel diseases (IBD). Professional pipelines are complex, but tools for the manual selection and further downstream analysis of single cell populations are missing so far. We developed a tool called scSELpy, which can easily be integrated into Scanpy-based pipelines, allowing the manual selection of cells on single cell transcriptomic datasets by drawing polygons on various data representations. The tool further supports the downstream analysis of the selected cells and the plotting of results. Taking advantage of two previously published single cell RNA sequencing datasets we show that this tool is useful for the positive and negative selection of T cell subsets implicated in IBD beyond standard clustering. We further demonstrate the feasibility for subphenotyping T cell subsets and use scSELpy to corroborate earlier conclusions drawn from the dataset. Moreover, we also show its usefulness in the context of T cell receptor sequencing. Collectively, scSELpy is a promising additive tool fulfilling a so far unmet need in the field of single cell transcriptomic analysis that might support future immunological research.

Impact of Single Hemodialysis Treatment on immune Cell Subpopulations.

Hemodialysis (HD) is known to trigger a chronic inflammatory status, affecting the innate and acquired immune response. This study was aimed at a comparative analysis of immune cell subsets, proliferation, and apoptosis in subjects receiving chronic HD treatment with respect to a healthy control. Regardless of the dialysis filter used, we observed a reshaping of the acquired immune component both with respect to healthy patients and between the various sessions of dialysis treatment, with an impairment of CD3 cells, along with an increase in CD4 and CD8 cell populations producing pro-inflammatory factors such as IL-17 and IFN-gamma. The population of B cells, monocytes and NK cells were not impaired by the dialysis procedure. These results confirmed the high impact of the HD treatment on the patient's immune system, underlying the imbalance of T cell counterparts.