Non-classical Monocytes Research Articles

Infection of nonclassic monocytes by respiratory syncytial virus induces an imbalance in the CD4+ T-cell subset response.

Respiratory syncytial virus (RSV) causes lower respiratory tract infections in infants and young children, leading to a pathogenesis-associated imbalance in CD4+ T-cell subsets and monocyte subsets. To investigate whether RSV affects the imbalance of CD4+ T-cells through monocytes, we examined the effects of the RSV-infected monocyte subset on CD4+ T-cell subsets, namely, Th1, Th2, Th17, and regulatory T (Treg) subsets, on proliferation in vitro and identified key monocyte-derived cytokines. We found that RSV efficiently infects CD16+ monocytes, but not CD16- monocytes, via cocultures of CD4+ T-cells with RSV-infected CD16+ monocytes, inhibits Treg cell proliferation and increases Th2 cell frequency, suggesting that RSV causes an imbalance in the CD4+ T-cell subset by primarily infecting CD16+ monocytes. Our data also revealed that IL-1β and IL-10 are key cytokines responsible for the activities of RSV-infected CD16+ monocytes. In a mouse model, we found that high-efficiency RSV infection of mouse Ly6C- monocytes, corresponding to CD16+ monocytes in humans, and adoptive transfer of Ly6C- monocytes during RSV infection decreased the Treg frequency in the lungs and aggravated pneumonia. Our data indicate that RSV can increase its pathogenesis through infection of nonclassic monocytes, leading to a CD4+ T-cell imbalance.IMPORTANCEThis study identified a pathogenesis pathway related to the RSV-nonclassic monocyte-IL-1β/IL-10-CD4+ T-cell subset balance, which links the heterogeneity of monocytes to RSV pathogenesis and elucidates a new mechanism by which RSV infection disrupts the balance of CD4+ T cells during RSV infection. These new findings provide potential therapeutic targets for RSV infection.

297 Immune Complex Induced Migration of Slan+ Non-Classical Monocytes and Its Implications in Systemic Lupus Erythematosus

297 Immune Complex Induced Migration of Slan+ Non-Classical Monocytes and Its Implications in Systemic Lupus Erythematosus

302 Immune complex induced cell migration and cytokine production of non-classical monocytes are defined by FcyRIII-genotype and IgG glycosylation

302 Immune complex induced cell migration and cytokine production of non-classical monocytes are defined by FcyRIII-genotype and IgG glycosylation

Uncovering immune cell-associated genes in breast cancer: based on summary data-based Mendelian randomized analysis and colocalization study

BackgroundBreast cancer, which is the most prevalent form of cancer among women globally, encompasses various subtypes that demand distinct treatment approaches. The tumor microenvironment and immune response are of crucial significance in the development and progression of breast cancer. Nevertheless, there has been scant evidence concerning the genes within breast cancer - specific immune cells.MethodsWe utilized summary data-based Mendelian randomization (SMR) to identify genes associated with breast cancer by utilizing expression quantitative trait loci (eQTL) datasets for 14 different immune cell types and genome-wide association studies (GWAS) for overall breast cancer and its subtypes. Furthermore, colocalization analysis was carried out to evaluate whether the observed association in SMR analyses is influenced by the same causal variant. Replication analysis and bulk RNA sequencing (bulkRNA-seq) analysis were employed to validate promising immune genes as potential drug targets.ResultsAfter correcting for the rate of false discovery, we discovered a total of 17 genes in 9 immune cell types that were significantly associated with overall breast cancer and its subtypes. The genes KCNN4, L3MBTL3, ZBTB38, MDM4, and TNFSF10 were identified in overall breast cancer and its subtypes. Colocalization analyses provided robust evidence in support of these associations. Notably, the KCNN4 gene in non-classical MONOcytes (MONOnc) was further validated through replication analysis and bulkRNA-seq analysis.ConclusionIn summary, our research has revealed a repertoire of genes within diverse immune cells associated with breast cancer. KCNN4 gene in non-classical MONOcytes (MONOnc) exhibited a negative association with overall breast cancer and its subtypes, which was identified as a potential drug target for breast cancer, opening up new avenues for therapeutic interventions.

An integrated single-cell atlas of blood immune cells in aging

Recent advances in single-cell technologies have facilitated studies on age-related alterations in the immune system. However, previous studies have often employed different marker genes to annotate immune cell populations, making it challenging to compare results. In this study, we combined seven single-cell transcriptomic datasets, comprising more than a million cells from one hundred and three donors, to create a unified atlas of human peripheral blood mononuclear cells (PBMC) from both young and old individuals. Using a consistent set of marker genes for immune cell annotation, we standardized the classification of immune cells and assessed their prevalence in both age groups. The integrated dataset revealed several consistent trends related to aging, including a decline in CD8+ naive T cells and MAIT cells and an expansion of non-classical monocyte compartments. However, we observed significant variability in other cell types. Our analysis of the long non-coding RNA MALAT1hi T cell population, previously implicated in age-related T cell exhaustion, showed that this population is highly heterogeneous with a mixture of naïve-like and memory-like cells. Despite substantial variation among the datasets when comparing gene expression between age groups, we identified a high-confidence signature of CD8+ naive T cell aging marked by an increased expression of pro-inflammatory genes. In conclusion, our study emphasizes the importance of standardizing existing single-cell datasets to enable the comprehensive examination of age-related cellular changes across multiple datasets.

Early immune profiling reveals distinct inflammatory responses between children and adults few days after primary SARS-CoV-2 infection.

To date, it is still not clear why during the COVID-19 pandemic children generally developed no or milder symptoms compared to adults. As innate immune responses are crucial in the early defense against pathogens, we aimed at profiling these responses from both adults and children with a primary SARS-CoV-2 infection. In the first months of the pandemic, PBMCs and serum were collected from peripheral blood of adults and children at different time points after testing SARS-CoV-2 PCR positive (PCR+). The levels of SARS-CoV-2 Spike-specific IgG were measured in serum. The cells were cultured for 24 hours in medium only, with heat inactivated SARS-CoV-2 (iSARS-CoV-2) or toll-like receptor (TLR) ligands. The levels of secreted cytokines/chemokines as well as monocyte phenotype were determined. Few days after testing PCR+, PBMCs from PCR+ children secreted higher levels of cytokines/chemokines compared to PCR+ adults, after these cells were incubated either in medium only or after stimulation with iSARS-CoV-2 or TLR ligands. Furthermore, PBMCs from children stimulated with iSARS-CoV-2 secreted significantly higher levels of IL-10 and GM-CSF compared to PBMCs from control children. In contrast, PBMCs from the PCR+ adults secreted lower levels of IL-8 compared to adult controls. Phenotypic analysis of monocytes indicates a smaller proportion non-classical monocytes for adults compared to children. The distinct cytokine profiles, symptom severity, and the proportion of non-classical monocytes correlated to each other. The levels of Spike-specific IgG overtime did not significantly differ between children and adults. Within the first week after testing PCR+, children showed a stronger inflammatory innate immune profile and experienced less severe symptoms compared to adults. Our data implies correlations between the secretion of cytokines/chemokines, proportion of non-classical monocytes, and symptoms severity. These findings enhance our understanding of the distinct pediatric and adult innate immune profile after SARS-CoV-2 infection and contributes to the knowledge necessary to improve future prevention strategies.

PCSK9 and its relationship with HMGB1, TLR4, and TNFα in non-statin and statin-treated coronary artery disease patients.

Despite statin use in coronary artery disease (CAD), significant risk remains, potentially due to increased proprotein convertase subtilisin/kexin-type 9 (PCSK9) production, which raises LDL-C levels and induces inflammation. The exact relationship between PCSK9, inflammatory markers like TNFα, TLR4, CRP, and HMGB1, and monocyte subsets is poorly understood. This study aimed to explore these relationships in non-statin and statin-taking CAD patients. This case-control study included 91 controls and 91 stable CAD patients, divided into no-statin (NS, n = 25), low-dose statin (LDS, n = 25), and high-dose statin (HDS, n = 41) groups. Serum levels of LDL-C, CRP, PCSK9, TLR4, HMGB1, and TNFα were measured. Monocyte subsets were classified using flow cytometry into classical monocytes (CM), intermediate monocytes (IM), and non-classical monocytes (NCM). CAD patients showed elevated PCSK9, LDL-C, and inflammatory markers compared to controls. Statin groups (LDS, HDS) had lower LDL-C and inflammatory markers but higher PCSK9 than the NS group, with the HDS group showing the lowest LDL-C and inflammatory markers but the highest PCSK9. In the NS group, PCSK9 positively correlated with inflammatory markers (HMGB1, TNFα, TLR4, CRP) and monocyte subsets (IM%, NCM%). In the total statin group (LDS + HDS), PCSK9 negatively correlated with HMGB1, TLR4, and NCM%, for each, respectively, and positively with CM%. Multivariable linear regression showed significant associations between PCSK9 and HMGB1, NCM%, and IM% in the NS group, and HMGB1, NCM%, and TLR4 in the total statin group. In conclusion, we recommend combining PCSK9 inhibitors with statins in high-risk CAD patients. This may enhance statin efficacy, reduce LDL-C, and inhibit the TLR4/NF-кB inflammatory pathway, decreasing atherosclerotic inflammation.

Single cell RNA-seq reveals cellular and transcriptional heterogeneity in the splenic CD11b+Ly6Chigh monocyte population expanded in sepsis-surviving mice

BackgroundSepsis survivors exhibit immune dysregulation that contributes to poor long-term outcomes. Phenotypic and functional alterations within the myeloid compartment are believed to be a contributing factor. Here we dissect the cellular and transcriptional heterogeneity of splenic CD11b+Ly6Chigh myeloid cells that are expanded in mice that survive the cecal ligation and puncture (CLP) murine model of polymicrobial sepsis to better understand the basis of immune dysregulation in sepsis survivors.MethodsSham or CLP surgeries were performed on C57BL/6J and BALB/c mice. Four weeks later splenic CD11b+Ly6Chigh cells from both groups were isolated for phenotypic (flow cytometry) and functional (phagocytosis and glycolysis) characterization and RNA was obtained for single-cell RNA-seq (scRNA-seq) and subsequent analysis.ResultsCD11b+Ly6Chigh cells from sham and CLP surviving mice exhibit phenotypic and functional differences that relate to immune function, some of which are observed in both C57BL/6J and BALB/c strains and others that are not. To dissect disease-specific and strain-specific distinctions within the myeloid compartment, scRNA-seq analysis was performed on CD11b+Ly6Chigh cells from C57BL/6J and BALB/c sham and CLP mice. Uniform Manifold Approximation and Projection from both strains identified 13 distinct clusters of sorted CD11b+Ly6Chigh cells demonstrating significant transcriptional heterogeneity and expressing gene signatures corresponding to classical-monocytes, non-classical monocytes, M1- or M2-like macrophages, dendritic-like cells, monocyte-derived dendritic-like cells, and proliferating monocytic myeloid-derived suppressor cells (M-MDSCs). Frequency plots showed that the percentages of proliferating M-MDSCs (clusters 8, 11 and 12) were increased in CLP mice compared to sham mice in both strains. Pathway and UCell score analysis in CLP mice revealed that cell cycle and glycolytic pathways were upregulated in proliferating M-MDSCs in both strains. Notably, granule protease genes were upregulated in M-MDSCs from CLP mice. ScRNA-seq analyses also showed that phagocytic pathways were upregulated in multiple clusters including the classical monocyte cluster, confirming the increased phagocytic capacity in CD11b+Ly6Chigh cells from CLP mice observed in ex vivo functional assays in C57BL/6J mice.ConclusionThe splenic CD11b+Ly6Chigh myeloid populations expanded in survivors of CLP sepsis correspond to proliferating cells that have an increased metabolic demand and gene signatures consistent with M-MDSCs, a population known to have immunosuppressive capacity.

Immunopathological markers and cell types linked to COVID-19 symptom manifestation

BackgroundNumerous studies have investigated the molecular properties that contribute to the symptoms of COVID-19, such as the virus’s genetic makeup, its replication mechanisms, and how it interacts with host cells. However, identifying the immunopathological properties, such as the immune system’s response, cytokine levels, and the presence of specific biomarkers, that are associated with the severity of the infection remains crucial for developing effective treatments and preventions.MethodsWe analyzed blood protein factor profiles from 420 individuals to identify features differentiating between test-negative healthy, asymptomatic, and symptomatic individuals using statistical comparison and the least absolute shrinkage and selection operator (i.e., LASSO) algorithm. Additionally, we examined single-cell RNA sequencing data from 141 individuals to identify specific cell types associated with the COVID-19 symptoms.ResultsHealthy individuals who tested negative had distinct blood protein factor levels compared to asymptomatic individuals. We identified two key protein factors, Serpin A10 and Complement C9, that differentiate between asymptomatic and symptomatic patients. Symptomatic patients showed lower levels of CD4+ T naïve, CD4+ T effector & memory, and CD8+ T naïve cells, along with higher levels of CD14+ classical monocytes compared to asymptomatic patients. Additionally, CD16+ non-classical monocytes, major producers of C1QA/B/C, appeared to contribute to the observed Complement C9 levels.ConclusionsThese findings advance our understanding of the immunopathological mechanisms underlying COVID-19 and may inform the development of targeted therapies and preventative measures. Future research should focus on further elucidating these mechanisms and exploring their potential clinical applications in managing COVID-19 severity.

Complement proteins and complement regulatory proteins are associated with age-related macular degeneration stage and treatment response

BackgroundDysregulation of the complement system is involved in development of age-related macular degeneration (AMD). The complement cascade is regulated by membrane bound complement regulatory proteins (Cregs) on mononuclear leukocytes among others. This study aims to investigate systemic complement proteins and Cregs in AMD stages and their association with treatment response in neovascular AMD (nAMD).MethodsIn this clinical prospective study, treatment-naïve patients with nAMD, intermediate AMD (iAMD) and healthy controls were recruited and systemic complement proteins C3, C3a and C5a were investigated with electrochemiluminescence immunoassays, and Creg expression (CD35, CD46 and CD59) on T cells (CD4 + and CD8+) and monocytes (classical, intermediate and non-classical) investigated with flow cytometry. Treatment response in nAMD patients was evaluated after loading dose and after one year, and categorized as good, partial or poor. Complement proteins and Creg expression levels were compared between healthy controls, iAMD and nAMD, as well as between good, partial and poor nAMD treatment response groups. Polymorphisms in the CFH and ARMS2 genes were analyzed and compared to complement proteins and Creg expression levels in nAMD patients.ResultsOne hundred patients with nAMD, 34 patients with iAMD and 61 healthy controls were included. 94 nAMD patients completed the 1-year follow-up. Distribution of treatment response in nAMD was 61 (65%) good, 26 (28%) partial, and 7 (7%) poor responders. The distribution of 1-year treatment response was 50 (53%) good, 33 (36%) partial, and 11 (11%) poor responders. The concentrations of systemic C3, C3a, and the C3a/C3-ratio were significantly increased in patients with nAMD compared to healthy controls (P < 0.001, P = 0.002, and P = 0.035, respectively). Systemic C3 was also increased in iAMD compared to healthy controls (P = 0.031). The proportion of CD46 + CD4 + T cells and CD59 + intermediate monocytes were significantly decreased in patients with nAMD compared to healthy controls (P = 0.018 and P = 0.042, respectively). The post-loading dose partial treatment response group had significantly lower concentrations of C3a and C5a compared to the good response group (P = 0.005 and P = 0.042, respectively). The proportion of CD35 + monocytes was significantly lower in the 1-year partial response group compared to the 1-year good response group (P = 0.039). High-risk CFH genotypes in nAMD patients was associated with increased C3a, C3a/C3-ratio, and expression levels of CD35 + CD8 + T cells and CD46 + classical monocytes, while expression level of CD46 + non-classical monocytes was decreased.ConclusionElevated concentrations of systemic complement proteins were found in patients with iAMD and nAMD. Decreased Creg expression levels were found in patients with nAMD. Partially responding nAMD patients had a dysregulated complement system and Cregs compared to good responders.

Triple immunostaining demonstrates the possible existence of segregated-nucleus-containing atypical monocytes in human primary myelofibrosis bone marrow: a case report

BackgroundSegregated-nucleus-containing atypical monocytes have recently been identified in mice. Segregated-nucleus-containing atypical monocytes are thought to originate from the bone marrow and induce fibrosis in the drug-injured lung. The Lyc6c− murine monocyte subset is the counterpart to human CD14−CD16++ non-classical monocytes; however, the human counterpart to murine segregated-nucleus-containing atypical monocytes has not yet been identified. Primary myelofibrosis is a well-known disease of progressive marrow fibrosis, and atypical megakaryocytes are thought to be closely related to fibrosis in primary myelofibrosis bone marrow. However, recently, monocytes have been reported to play an important role in marrow fibrosis in primary myelofibrosis. We speculated that, if there is a human counterpart to murine segregated-nucleus-containing atypical monocytes, it would present the same markers as murine segregated-nucleus-containing atypical monocytes, such as CD14−CD16+ macrophage-1 antigen (CD11b/CD18 complex)+, MSR1+, and CEACAM1+, and it might exist in the bone marrow of patients with primary myelofibrosis.Case presentationA 74-year-old Japanese male visited our hospital for clinical follow-up after total prostatectomy for prostatic cancer. Anemia, thrombocytosis, and elevated lactate dehydrogenase were suddenly observed in a periodic examination. CALR mutation type 2 (p.K385fs*47) was observed. The histological features of the patient’s bone marrow were consistent with fibrotic primary myelofibrosis. We immunohistochemically studied the bone marrow in an attempt to identify a human counterpart to murine segregated-nucleus-containing atypical monocytes. We detected a few CD16+MSR1+CEACAM1+ cells, but not CD14+MSR1+CEACAM1+ cells, by triple immunostaining. The patient is in a good condition and does not require treatment for primary myelofibrosis.ConclusionThere is a possibility that human segregated-nucleus-containing atypical monocytes exist in the bone marrow of primary myelofibrosis patients and might be related to marrow fibrosis.

Peripheral innate immunophenotype in neurodegenerative disease: blood-based profiles and links to survival.

The innate immune system plays an integral role in the progression of many neurodegenerative diseases. In addition to central innate immune cells (e.g., microglia), peripheral innate immune cells (e.g., blood monocytes, natural killer cells, and dendritic cells) may also differ in these conditions. However, the characterization of peripheral innate immune cell types across different neurodegenerative diseases remains incomplete. This study aimed to characterize peripheral innate immune profiles using flow cytometry for immunophenotyping of peripheral blood mononuclear cells in n = 148 people with Alzheimer's disease (AD), frontotemporal dementia (FTD), corticobasal syndrome (CBS), progressive supranuclear palsy (PSP), Lewy body dementia(LBD) as compared to n = 37 healthy controls. To compare groups, we used multivariate dissimilarity analysis and principal component analysis across 19 innate immune cell types. We identified pro-inflammatory profiles that significantly differ between patients with all-cause dementia and healthy controls, with some significant differences between patient groups. Regression analysis confirmed that time to death following the blood test correlated with the individuals' immune profile weighting, positively to TREM2+ and non-classical monocytes and negatively to classical monocytes. Taken together, these results describe transdiagnostic peripheral immune profiles and highlight the link between prognosis and the monocyte cellular subdivision and function (as measured by surface protein expression). The results suggest that blood-derived innate immune profiles can inform sub-populations of cells relevant for specific neurodegenerative diseases that are significantly linked to accelerated disease progression and worse survival outcomes across diagnoses. Blood-based innate immune profiles may contribute to enhanced precision medicine approaches in dementia, helping to identify and monitor therapeutic targets and stratify patients for candidate immunotherapies.

Patients with coronary atherosclerosis had an altered ratio of monocyte subpopulations in the blood, which was associated with an inflammatory cell response

Coronary artery disease (CAD) is one of the leading causes of death in developed countries. Experimental data confirm the role of monocytes in the development of CAD. Three main subpopulations of circulating blood monocytes are known: classical CD14++CD16- (~80%), intermediate CD14+CD16+ (~5%) and non-classical CD14+CD16++(~15%). It is believed that each of the subpopulations of monocytes performs different functions. There are studies that demonstrate that classical monocytes respond more to the bacterial presence, whereas non-classical ones respond to the viral one. However, the functions of monocyte subpopulations have not been fully studied. Previously, we demonstrated that circulating monocytes of the blood of patients with atherosclerosis had increased proinflammatory activity. We decided to find out how the ratio of monocyte subpopulations in the blood is related to the inflammatory response of cells in atherosclerosis. The aim of our work was to investigate the relationship of the inflammatory response of primary monocytes with the distribution of monocyte subpopulations relative to the total pool of monocytes in healthy and sick CAD. The study included 20 men aged 46 to 70 years, 10 of them without CAD and 10 patients with CAD. A coronary angiography was performed, according to the results of which the patients were divided into patients with coronary atherosclerosis with detected stenosis in 2 or more arteries (CAD) and healthy ones without stenosis in the arteries. Next, blood was taken to study circulating monocytes. Monocyte subpopulations were detected by flow cytometry from the leukocyte fraction using antibodies against CD14- FITC and CD16-PB450-A. Immediately after isolation, monocytes were stimulated with LPS with a final concentration of 1 ug/mL, and a supernatant was selected 24 hours later for further enzyme immunoassay. The inflammatory response was assessed by the secretion of cytokines TNFα, IL-1β, IL-6, IL-8, IL-10, and CCL2 using ELISA. The monocytes of CAD patients had an altered inflammatory response in response to LPS stimulation compared to patients without CAD. This was manifested in increased secretion of IL-1β and TNF, and decreased secretion of CCL2 and IL-6. An increase in the number of intermediate and non-classical monocytes in patients with CAD was associated with changes in the inflammatory response of cells to the secretion of cytokines IL-1β and CCL2. It can be assumed that pathological changes in the representation of monocyte subpopulations in the bloodstream may be one of the causes of chronic inflammation in the walls of the arteries, contributing to the progression of atherosclerotic lesions.

Non-classical monocyte levels correlate negatively with HIV-associated cerebral small vessel disease and cognitive performance.

Despite antiretroviral treatment (cART), aging people living with HIV (PWH) are more susceptible to neurocognitive impairment (NCI) probably due to synergistic/additive contribution of traditional cerebrovascular risk factors. Specifically, transmigration of inflammatory CD16+ monocytes through the altered blood brain barrier (BBB) may exacerbate cerebral small vessel disease (CSVD), a known cause of vascular cognitive impairment. PWH on cART (n=108) and age, sex, and Reynold's cardiovascular risk score-matched uninfected individuals (PWoH, n=111) were enrolled. This is a longitudinal observational study but only cross-sectional data from entry visit are reported. Neuropsychological testing and brain magnetic resonance imaging (MRI) were performed. CSVD was diagnosed by Fazekas score ≥1. Flow cytometric analyses of fresh whole blood were conducted to evaluate circulating levels of monocyte subsets (classical, intermediate, and non-classical) and markers of monocyte activation (CCR2, CD40, PSGL-1, TNFR2 and tissue factor). ELISAs were used to measure sCD14, ICAM, and Osteoprotegerin. Two-way analysis of variance (ANOVA), and linear regression models were performed to study the effects of HIV status, CSVD status, and their interaction to outcome variables such as cognitive score. Two-sample t-tests and correlation analyses were performed between and within PWoH with CSVD and PWH with CSVD participants. PWH with CSVD (n=81) had significantly lower total cognitive scores, higher levels of NCMs and soluble CD14 and intracellular adhesion molecule 1 (ICAM-1) as compared to PWoH with CSVD group (n=68). sCD14 and ICAM1 were positively correlated with each other indicating that monocyte and endothelial activation are associated with each other. Cognition was negatively correlated with NCMs, especially in the PWH with CSVD group. Among other blood biomarkers measured, osteoprotegerin levels showed mild negative correlation with cognitive performance in individuals with CSVD irrespective of HIV status. Elevated levels of NCMs may contribute to neuroinflammation, CSVD and subsequent cognitive impairment. This finding is of particular relevance in aging PWH as both HIV and aging are associated with increased levels of NCMs. NCMs may serve as a potential biomarker to address these comorbidities. Further longitudinal studies are needed to evaluate whether changes in NCM levels are associated with changes in CSVD burden and cognitive impairment.

Update on the immunological mechanisms of primary graft dysfunction and chronic lung allograft dysfunction.

Primary graft dysfunction (PGD) and chronic lung allograft dysfunction (CLAD) are the leading causes of graft loss in lung transplant recipients. The development of mouse lung transplant models has allowed for the genetic dissection of cellular and molecular pathways that prevent graft survival. This review provides an overview into recent mechanistic insights into PGD and CLAD. Mouse orthotopic lung transplant models and investigations of human lung transplant recipeints have revealed new molecular and cellular targets that promote PGD and CLAD. Donor and recipient-derived innate immune cells promote PGD and CLAD. PGD is driven by communication between classical monocytes and tissue-resident nonclassical monocytes activating alveolar macrophages to release chemokines that recruit neutrophils. Products of cell damage trigger neutrophil NET release, which together with NK cells, antibodies and complement, that further promote PGD. The development of CLAD involves circuits that activate B cells, CD8 + T cells, classical monocytes, and eosinophils. Effective targeted management of PGD and CLAD in lung transplant recipient to improve their long-term outcome remains a critical unmet need. Current mechanistic studies and therapeutic studies in mouse models and humans identify new possibilities for prevention and treatment.

Flow Cytometric Immunophenotyping: Minimal Differences in Fresh and Cryopreserved Peripheral Blood Mononuclear Cells versus Whole Blood.

Background/Objectives: Flow cytometry is a convenient tool in immunophenotyping for monitoring the status of immunological conditions and diseases. The aim of this study was to investigate the effect of isolation and cryopreservation by flow cytometric analysis on subpopulations of CD4+ T helper (Th), T regulatory (Treg), CD8+ T cytotoxic (Tc), CD56+ NK, CD19+ B and monocytes. Freshly isolated and cryopreserved peripheral blood mononuclear cells (PBMCs) were compared to fresh whole blood. Methods: Peripheral blood was collected from healthy donors and prepared for flow cytometric analysis using the same panels of antibodies throughout the study. Results: Comparisons between fresh (F)- and cryopreserved (C)-PBMCs showed no major differences in percentages of CD4+, Th1, Th2 and CD4+CD25+CD127low Treg cells. No differences in percentage of CD8+ or subpopulations of naive/stem, central or effector memory cells were observed between F- and C-PBMCs. The percentage of CD56+ NK cells, CD19+ B cells or classical and nonclassical monocytes did not differ between F-and C-PBMCs either. On the contrary, whole blood had lower percentages of Th and NK cells but higher percentages of Th1, Th17, Th1Th17, Tregs, Tc and B cells compared to C-PBMCs, while it had a higher proportion of Tc compared to F-PBMCs. Conclusions: Flow cytometric immunophenotyping minimally differs between freshly isolated and cryopreserved PBMCs. This implies the possibility of cryostorage of cohorts for later analysis. Importantly, care must be taken when comparing results from whole blood with isolated and cryopreserved PBMCs. Collectively, these results can contribute to the standardization of flow cytometric protocols in both clinical and research settings.

Single-cell analysis of the multiple myeloma microenvironment after γ-secretase inhibition and CAR T-cell therapy

AbstractChimeric antigen receptor (CAR) T cells and bispecific antibodies targeting B-cell maturation antigen (BCMA) have significantly advanced the treatment of relapsed and refractory multiple myeloma. Resistance to BCMA-targeting therapies, nonetheless, remains a significant challenge. BCMA shedding by γ-secretase is a known resistance mechanism, and preclinical studies suggest that inhibition may improve anti-BCMA therapy. Leveraging a phase 1 clinical trial of the γ-secretase inhibitor (GSI), crenigacestat, with anti-BCMA CAR T cells (FCARH143), we used single-nuclei RNA sequencing and assay for transposase-accessible chromatin sequencing to characterize the effects of GSI on the tumor microenvironment. The most significant impacts of GSI involved effects on monocytes, which are known to promote tumor growth. In addition to observing a reduction in the frequency of nonclassical monocytes, we also detected significant changes in gene expression, chromatin accessibility, and inferred cell-cell interactions after exposure to GSI. Although many genes with altered expression are associated with γ-secretase–dependent signaling, such as Notch, other pathways were affected, indicating GSI has far-reaching effects. Finally, we detected monoallelic deletion of the BCMA locus in some patients with prior exposure to anti-BCMA therapy, which significantly correlated with reduced progression-free survival (PFS; median PFS, 57 vs 861 days). GSIs are being explored in combination with the full spectrum of BCMA-targeting agents, and our results reveal widespread effects of GSI on both tumor and immune cell populations, providing insight into mechanisms for enhancing BCMA-directed therapies.

Monocyte subsets in breast cancer patients under treatment with aromatase inhibitor and mucin-1 cancer vaccine

BackgroundMonocytes comprise subsets of classical, intermediate and non-classical monocytes with distinct anti- or pro-tumor effects in breast cancer (BC). They are modulated by estrogen, and can contribute to BC control by endocrine therapy in preclinical models.MethodsTo elucidate whether changes in monocyte subsets are associated with treatment and response, we investigated peripheral blood samples of 73 postmenopausal women with estrogen receptor (ER) positive BC, who received aromatase inhibitor therapy with or without the mucin-1 vaccine tecemotide in the ABCSG34 trial. Blood was retrieved at baseline, midterm and end of therapy, and was analyzed for the distribution and ER expression of monocyte subsets by flow cytometry.ResultsWhen 40 healthy, age-matched women were compared with BC patients before treatment start, ER levels of monocytes did not differ, yet patients presented with a higher frequency of classical and fewer non-classical monocytes. Endocrine therapy triggered a significant increase in ER levels in all monocyte subsets, without affecting subset distribution. Vaccination had no overall impact on subset frequency and ER expression. Yet, a shift from intermediate to classical monocytes during therapy correlated with changes in plasma cytokines and chemokines and was significantly associated with low residual cancer burden in vaccinated patients. Without tecemotide, baseline ER levels in classical monocytes were significantly higher in women with good response to endocrine therapy.ConclusionsThis study identified classical monocytes to be associated with ER positive BC and with patient response to neoadjuvant endocrine treatment and cancer vaccination.

12407 Assessing Human Monocyte Migration And Co-culture With Adrenocortical Cancer Cells

Abstract Disclosure: C. Hong: None. S. Feely: None. R. Challapalli: None. N. Mullen: None. A. Sorushanova: None. C. Hantel: None. M.D. Griffin: None. M.C. Dennedy: None. Adrenocortical carcinoma (ACC) is a lipid, typically steroidogenic cancer which carries a 5-year prognosis of &amp;lt;10%. Therapeutic options are limited including surgery and mitotane – a poorly tolerated and efficacious insecticide. Recent data have demonstrated that the immune environment of adrenocortical carcinoma is deficient in lymphocytes while demonstrating a relative rich monocyte/macrophage population in the tumour microenvironment. We have investigated the gradient for migration of circulating peripheral monocytes to ACC. ACC cells were seeded in the bottom chamber of the transwell system. Monocytes were isolated from human peripheral blood, by negative selection using magnetic beads with high purity (&amp;gt;95%) and quality. Migration of monocytes at 24/48h was evaluated by identifying those remaining in the top chamber, the floating fraction in the bottom chamber and those adherent to ACC cells in the bottom chamber. Analysis of monocyte/macrophages was undertaken by flow cytometry using the following markers: Sytox Blue, CD45, CD14, CD16 and HLA-DR. At 24h, when compared to control conditions, more monocytes had migrated to the ACC cells seeded lower chamber and attached to the bottom. Similar results were observed in migration at 48h. Predominantly Classical monocytes (CD14++CD16-HLA-DR+) migrated to metastatic cancer cells (MUC1), and Non-Classical monocytes (CD14+CD16+HLA-DR+) migrated to primary cancer cells (H295R/ HAC15) at 48h. We then investigated the polarization cytokine profile of migrated monocytes with or without ACC cells at 72 h by multiplex bead-based assay. Migrated monocytes indicated a significant shift toward the M2 phenotype in the presence of H295R or HAC15. The production of the pro-inflammatory factors of IL-6, TNF-alpha, etc. decreased and immunosuppressive factors of IL-10, TARC, etc. increased. MUC1 didn’t increase M2 or M1 cytokine secretion. Moreover, surface markers of migrated monocytes were evaluated at 72h by flow cytometry. When compared to the control group, all 3 ACC cell lines switched monocytes/ macrophages into M2 phenotype, as evidenced by the decrease in the expression of the M1 marker CD86 and the increase in the expression of the M2 markers CD163 and CD206. We demonstrate monocytes migrate and associate with ACC cells: (i) subpopulations differ in transmigration properties in response to ACC cells (ii) monocytes/macrophages exhibit M2 polarization phenotype. Presentation: 6/2/2024

Integrated Single-cell RNA-seq and Bulk RNA-seq Identify Diagnostic Biomarkers for Postmenopausal Osteoporosis.

We aimed to explore diagnostic biomarkers of postmenopausal osteoporosis (PMOP). PMOP brings enormous physical and economic burden to elderly women. This study aims to screen new biomarkers for osteoporosis, providing insights for early diagnosis and therapeutic targets of osteoporosis. Weighted gene co-expression network analysis (WGCNA) was applied to identify osteoporosis-related hub genes. Single-cell transcriptomic atlas of osteoporosis was depicted and the heterogeneity of monocytes was analyzed, based on which the biomarkers for osteoporosis were screened. Gene set enrichment analysis (GSEA) was conducted on the biomarkers. The diagnostic model (nomogram) was established and evaluated based on the expression levels of biomarkers. Additionally, the transcription factor (TF) regulatory network was constructed to predict the potential TF and targeted miRNA of biomarkers. The drugs with significant correlation with biomarkers were identified by Spearman correlation analysis. We obtained 30 osteoporosis-associated hub genes. 9 cell types were identified, and the monocytes were subdivided to 4 subtypes. Three biomarkers, DHX29, LSM5, and UBE2V2, were screened. DHX29 and UBE2V2 were highly expressed in non-classical monocytes, while LSM5 exhibited the highest expression in other monocytes, followed by non-classical monocytes. GSEA indicated that osteoporosis may be correlated with vascular calcification and the biomarkers may be involved in the formation of immune cells. Then, nomogram was constructed and exhibited good robustness. In addition, MYC and SETDB1 were the shared IF in three biomarkers, which may play critical regulatory roles in the progression of osteoporosis. Moreover, 41, 49, and 68 drugs appeared significant correlations with DHX29, LSM5, and UBE2V2, respectively. This study provided a basis for early diagnosis and targeted treatment of osteoporosis.