Clinical significance of monocyte heterogeneity

Profiling migration of human monocytes in response to chemotactic and barotactic guidance cues

Monocytes are critical to innate immunity, participating in chemotaxis during tissue injury, infection, and inflammatory conditions. However, the migration dynamics of human monocytes under different guidance cues are not well characterized. Here, we developed a microfluidic device to profile the migration characteristics of human monocytes under chemotactic and barotactic guidance cues while also assessing the effects of age and cytokine stimulation. Human monocytes preferentially migrated toward the CCL2 gradient through confined microchannels, regardless of donor age and migration pathway. Stimulation with interferon (IFN)-γ, but not granulocyte-macrophage colony-stimulating factor (GM-CSF), disrupted monocyte navigation through complex paths and decreased monocyte CCL2 chemotaxis, velocity, and CCR2 expression. Additionally, monocytes exhibited a bias toward low-hydraulic-resistance pathways in asymmetric environments, which remained consistent across donor ages, cytokine stimulation, and chemoattractants. This microfluidic system provides insights into the unique migratory behaviors of human monocytes and is a valuable tool for studying peripheral immune cell migration in health and disease.

α-linolenic acid mitigates microglia-mediated neuroinflammation of schizophrenia in mice by suppressing the NF-κB/NLRP3 pathway via binding GPR120-β-arrestin 2

BACKGROUND

Schizophrenia (SCZ) is a heterogeneous psychiatric disorder that is poorly treated by current therapies. Emerging evidence indicates that SCZ is closely correlated with a persistent neuroinflammation. α-linolenic acid (ALA) is highly concentrated in the brain and represents a modulator of the immune system by decreasing the inflammatory response in chronic metabolic diseases. This study was first designed to investigate the potential role of dietary ALA on cognitive function and neuroinflammation in mice with SCZ.

METHODS

In vivo, after 2 weeks of modeling, mice were treated with dietary ALA treatment for 6 weeks. In vitro, inflammation model was created using lipopolysaccharide as an inducer in BV2 microglial cells.

RESULTS

Our results demonstrated that ALA alleviated cognitive impairment and enhanced synaptic plasticity in mice with SCZ. Moreover, ALA mitigated systematic and cerebral inflammation through elevating IL-10 and inhibiting IL-1β, IL-6, IL-18 and TNF-α. Furthermore, ALA notably inhibited microglia and pro-inflammatory monocytes, as well as microglial activation andpolarization. Mechanistically, ALA up-regulated the expressions of G protein coupled receptor (GPR) 120 and associated β-inhibitor protein 2 (β-arrestin2), accompanied by observable weakened levels of transforming growth factor-β activated kinase 1 (TAK1), NF-κB p65, cysteine proteinase-1 (caspase-1), pro-caspase-1, associated speck-like protein (ASC) and NLRP3. In vitro, ALA directly restrained the inflammation of microglia by decreasing the levels of pro-inflammatory factors and regulating microglial polarization via GPR120-NF-κB/NLRP3inflammasome signaling pathway, whereas AH7614 definitely eliminated this anti-inflammatory effect of ALA.

CONCLUSION

Dietary ALA ameliorates microglia-mediated neuroinflammation by suppressing the NF-κB/NLRP3 pathway via binding GPR120-β-arrestin2.

The impact of CLDN18.2 expression on effector cells mediating antibody-dependent cellular cytotoxicity in gastric cancer

Activating antibody-dependent cellular cytotoxicity (ADCC) by targeting claudin-18 isoform 2 (CLDN18.2) using zolbetuximab, a monoclonal antibody against CLDN18.2, has been considered a promising novel therapeutic strategy for gastric cancer (GC). However, the impact of CLDN18.2 expression on natural killer (NK) cells and monocytes/macrophages-crucial effector cells of ADCC-in GC has not been fully investigated. In the present study, we assessed the impact of CLDN18.2 expression on clinical outcomes, molecular features, and the frequencies of tumor-infiltrating NK cells and macrophages, as well as peripheral blood NK cells and monocytes, in GC by analyzing our own GC cohorts. The expression of CLDN18.2 did not significantly impact clinical outcomes of GC patients, while it was significantly and positively associated with Epstein-Barr virus (EBV) status and PD-L1 expression. The frequencies of tumor-infiltrating NK cells and macrophages, as well as peripheral blood NK cells and monocytes, were comparable between CLDN18.2-positive and CLDN18.2-negative GCs. Importantly, both CLDN18.2 expression and the number of tumor-infiltrating NK cells were significantly higher in EBV-associated GC compared to other molecular subtypes. Our findings support the effectiveness of zolbetuximab in CLDN18.2-positive GC, and offer a novel insight into the treatment of this cancer type, highlighting its potential effectiveness for CLDN18.2-positive/EBV-associated GC.

Dissecting the mediating role of cytokines in the interaction between immune traits and sepsis: insights from comprehensive mendelian randomization

Background

Sepsis is a life-threatening organ dysfunction resulting from a dysregulated host response to infection, yet the potential causal relationship between the immunophenotype and sepsis remains unclear.

Methods

Genetic variants associated with the immunophenotype served as instrumental variables (IVs) in Mendelian randomization (MR) to elucidate the causal impact of the immunophenotype on three sepsis outcomes. Additionally, a two-step MR analysis was conducted to identify significant potential mediators between the immunophenotype and three sepsis outcomes.

Results

Our MR analysis demonstrated a significant association between the immunophenotype and sepsis outcome, with 36, 36, and 45 the immunophenotype associated with the susceptibility, severity, and mortality of sepsis, respectively. Specifically, our analysis highlighted the CD14+ CD16+ monocyte phenotype as a significant factor across all three sepsis outcomes, with odds ratios (ORs) and corresponding confidence intervals (CIs) indicating its impact on sepsis (OR = 1.047, CI: 1.001-1.096), sepsis in Critical Care Units (OR = 1.139, CI: 1.014-1.279), and sepsis-related 28-day mortality (OR = 1.218, CI: 1.104-1.334). Mediation analyses identified seven cytokines as significant mediators among 91 potential cytokines, including interleukin-5 (IL-5), S100A12, TNF-related apoptosis-inducing ligand (TRAIL), T-cell surface glycoprotein CD6 isoform, cystatin D, interleukin-18 (IL-18), and urokinase-type plasminogen activator (uPA). Furthermore, reverse MR analysis revealed no causal effect of sepsis outcomes on the immunophenotype.

Conclusion

Our MR study suggests that the immunophenotype is significantly associated with the susceptibility, severity, and mortality of patient with sepsis, providing, for the first time, robust evidence of significant associations between immune traits and their potential risks. This information is invaluable for clinicians and patients in making informed decisions and merits further attention.

Effects of extracorporeal circulation with different time on platelet count after cardiac surgery: a retrospective study based on medical records

Our objective was to observe the effects of extracorporeal circulation (ECC) with different time on platelet count in patients undergoing cardiac surgery. A total of 427 patients who underwent elective cardiac surgery under ECC in affiliated hospital of north Sichuan medical college from January 1, 2018 to July 31, 2021 were divided into three groups according to ECC time. We concluded that thrombocytopenia was common after ECC, maximum drop of the platelet counts after ECC was usually seen on the second day after ECC, and platelet counts started to recover on the fifth day after ECC. With the extension of ECC time, the drop in platelet counts is more pronounced, the volume of perioperative blood loss and blood products transfusion are more, and the recovery level and speed of platelet counts is lower.

Reticuloendothelial activation and phenotypic alteration of peripheral monocytes with enhanced liver recruitment drive liver injury secondary to yellow phosphorus

BACKGROUND AND AIM

Monocytes and macrophages play a crucial role in the pathogenesis of acute liver failure (ALF). We aimed to study reticuloendothelial activation and its correlation with disease severity in commonly encountered yellow phosphorus (rodenticide)-induced hepatotoxicity patients. We also studied peripheral monocyte phenotype in a subset of patients.

METHODS

Reticuloendothelial activation markers were analyzed and correlated with disease severity score in a prospectively collected database of yellow phosphorus-related hepatoxicity patients between 2018 and 2021. In a prospective cohort of these patients and age-matched healthy controls, peripheral blood monocyte phenotyping was performed.

RESULTS

Reticuloendothelial activation markers were analyzed in 67 patients [Age: 23(12-64) years; median (range), men: 25, acute liver injury (ALI): 38, ALF: 29, model for end-stage liver disease (MELD) score: 28 (7-40)] of yellow phosphorus-induced hepatotoxicity. Serum ferritin (927; 10.3-34 807 ng/mL), sCD163 (4.59; 0.11-12.7 μg/mL), sCD25 (3050; 5.6-17 300 pg/mL) and plasma von Willebrand factor (423.5, 103-1106 IU/dL) were increased and showed significant correlation with liver disease severity assessed by MELD score (ρ = 0.29, ρ = 0.6, ρ = 0.56 and ρ = 0.46 respectively). Phenotyping and serum immune markers were performed in seven patients (M: 4; age: 27, 15-37 years; median, range; MELD score: 36, 21-40) and compared with eight healthy controls. Increase in classical monocytes and decrease in patrolling and intermediate monocyte subsets were observed in ALF cohort. HLA-DRlow CD163hi (immune exhaustion), CD64hi (immune complex-mediated response), and CCR2hi (liver homing) monocyte phenotype was noted.

CONCLUSION

Altered peripheral monocyte phenotype with enhanced liver homing and macrophage activation, suggests important role of innate immune activation, and provides a potential therapeutic target, in yellow phosphorus-induced hepatotoxicity.

The role of monocytes in thrombotic diseases: a review

Cardiovascular and cerebrovascular diseases are the number one killer threatening people's life and health, among which cardiovascular thrombotic events are the most common. As the cause of particularly serious cardiovascular events, thrombosis can trigger fatal crises such as acute coronary syndrome (myocardial infarction and unstable angina), cerebral infarction and so on. Circulating monocytes are an important part of innate immunity. Their main physiological functions are phagocytosis, removal of injured and senescent cells and their debris, and development into macrophages and dendritic cells. At the same time, they also participate in the pathophysiological processes of pro-coagulation and anticoagulation. According to recent studies, monocytes have been found to play a significant role in thrombosis and thrombotic diseases of the immune system. In this manuscript, we review the relationship between monocyte subsets and cardiovascular thrombotic events and analyze the role of monocytes in arterial thrombosis and their involvement in intravenous thrombolysis. Finally, we summarize the mechanism and therapeutic regimen of monocyte and thrombosis in hypertension, antiphospholipid syndrome, atherosclerosis, rheumatic heart disease, lower extremity deep venous thrombosis, and diabetic nephropathy.

In-stent restenosis is associated with proliferative skin healing and specific immune and endothelial cell profiles: results from the RACHEL trial

Introduction

In-stent restenosis (ISR) is a major challenge in interventional cardiology. Both ISR and excessive skin healing are aberrant hyperplasic responses, which may be functionally related. However, the cellular component underlying ISR remains unclear, especially regarding vascular homeostasis. Recent evidence suggest that novel immune cell populations may be involved in vascular repair and damage, but their role in ISR has not been explored. The aims of this study is to analyze (i) the association between ISR and skin healing outcomes, and (ii) the alterations in vascular homeostasis mediators in ISR in univariate and integrative analyses.

Methods

30 patients with ≥1 previous stent implantation with restenosis and 30 patients with ≥1 stent without restenosis both confirmed in a second angiogram were recruited. Cellular mediators were quantified in peripheral blood by flow cytometry. Skin healing outcomes were analyzed after two consecutive biopsies.

Results

Hypertrophic skin healing was more frequent in ISR patients (36.7%) compared to those ISR-free (16.7%). Patients with ISR were more likely to develop hypertrophic skin healing patterns (OR 4.334 [95% CI 1.044-18.073], p=0.033), even after correcting for confounders. ISR was associated with decreased circulating angiogenic T-cells (p=0.005) and endothelial progenitor cells (p<0.001), whereas CD4+CD28null and detached endothelial cells counts were higher (p<0.0001 and p=0.006, respectively) compared to their ISR-free counterparts. No differences in the frequency of monocyte subsets were found, although Angiotensin-Converting Enzyme expression was increased (non-classical: p<0.001; and intermediate: p<0.0001) in ISR. Despite no differences were noted in Low-Density Granulocytes, a relative increase in the CD16- compartment was observed in ISR (p=0.004). An unsupervised cluster analysis revealed the presence of three profiles with different clinical severity, unrelated to stent types or traditional risk factors.

Conclusion

ISR is linked to excessive skin healing and profound alterations in cellular populations related to vascular repair and endothelial damage. Distinct cellular profiles can be distinguished within ISR, suggesting that different alterations may uncover different ISR clinical phenotypes.

Peripheral blood monocyte status is a predictor for judging occurrence and development on sepsis in older adult population: a case control study

BACKGROUND

Peripheral blood monocytes are important immune modulatory cells that change during aging. Previous studies on sepsis and monocytes did not distinguish between age groups, especially in the older adult population. The mechanisms of monocyte subsets and function are not well-understood in the aging context with sepsis.

METHODS

Monocyte subsets were measured using flow cytometry in 80 sepsis patients and 40 healthy controls. Plasma cytokine levels were measured using cytokine antibody arrays.

RESULTS

The percentage of MO3 (CD14 + CD16 + +)/monocytes was higher in sepsis patients than in controls (P = 0.011), whereas the percentage of MO1 (CD14 +  + CD16 -)/monocytes was higher in septic shock patients and 28-day death group than in those without shock and 28-day survival group (P = 0.034, 0.038). Logistic regression analysis showed that the percentage of MO3/monocytes (OR = 1.120, P = 0.046) and plasma level of monocyte chemoattractant protein (MCP)-1 (OR = 1.006, P = 0.023) were independently associated with the occurrence of sepsis, whereas the percentage of MO1/monocytes (OR = 1.255, P = 0.048) was independently associated with septic shock. The receiver operating characteristic (ROC) curve showed that the area under the curve (AUC) of MO3/monocyte percentage in combination with MCP-1 plasma level (AUC = 0.799) for predicting sepsis was higher than that of each parameter alone (P < 0.001). The AUC of MO1/monocyte percentage with the value 0.706 (P = 0.003) was lower than the AUC of SOFA (sequential organ failure assessment) score with the value 0.966 (P < 0.001) for predicting septic shock, but the value of the two AUCs were similar for predicting 28-day mortality (AUC = 0.705, 0.827; P = 0.020, P < 0.001). The AUC of MO1/monocytes percentage in combination with SOFA score for predicting 28-day mortality was higher than that of each parameter alone (AUC = 0.867, P < 0.001). Using a cut-off of 58.5% (for MO1/monocytes determined by ROC) could discriminate between survivors and non-survivors on Kaplan-Meier curves for 28-day mortality with a positive predictive value of 77.4%.

CONCLUSION

The MO3/monocyte percentage and plasma MCP-1 level were independent predictors of sepsis occurrence, whereas the percentage of MO1/monocytes was an independent predictor of prognosis in the Chinese Han older adult population.

TRIAL REGISTRATION

Registration number: ChiCTR2200061490, date of registration: 2022-6-26 (retrospectively registered).

Regulation of Synovial γδ T Cell Ligand Expression by Mitochondrial Reactive Oxygen Species and Gasdermin-D

γδ T cells reside at mucosal and epithelial barriers, and they often accumulate at sites of inflammation, both infectious and autoimmune, as well as in certain tumors. However, progress in understanding their function is considerably hampered by a lack of full understanding of the ligands recognized by TCR-γδ and how expression of these ligands is regulated. We recently developed a soluble human TCR-γδ (Vγ9Vδ1) tetramer from a synovial γδ T cell clone of a Lyme arthritis patient and observed that it stains monocytes activated by Borrelia burgdorferi. Those findings are extended in the current study to further examine the physiological regulation of ligand expression on monocytes. The TCR-γδ ligand is induced by a variety of TLR agonists and requires NF-κB activation. Of particular interest is that ligand expression also requires caspase activation of the inflammasome and is dependent on active metabolism, mitochondrial reactive oxygen species, and activation of gasdermin-D. Consistent with these observations, the TCR-γδ ligand is expressed by a subset of metabolically active CD14+CD16+ monocytes and colocalizes intracellularly with mitochondria. The findings suggest a model in which synovial γδ T cell ligand is a self-antigen whose surface expression is increased by inflammatory conditions and mitochondrial stress.

Immunometabolic Markers in a Small Patient Cohort Undergoing Immunotherapy

Although the discovery of immune checkpoints was hailed as a major breakthrough in cancer therapy, generating a sufficient response to immunotherapy is still limited. Thus, the objective of this exploratory, hypothesis-generating study was to identify potentially novel peripheral biomarkers and discuss the possible predictive relevance of combining scarcely investigated metabolic and hormonal markers with immune subsets. Sixteen markers that differed significantly between responders and non-responders were identified. In a further step, the correlation with progression-free survival (PFS) and false discovery correction (Benjamini and Hochberg) revealed potential predictive roles for the immune subset absolute lymphocyte count (rs = 0.51; p = 0.0224 *), absolute basophil count (rs = 0.43; p = 0.04 *), PD-1+ monocytes (rs = −0.49; p = 0.04 *), hemoglobin (rs = 0.44; p = 0.04 *), metabolic markers LDL (rs = 0.53; p = 0.0224 *), free androgen index (rs = 0.57; p = 0.0224 *) and CRP (rs = −0.46; p = 0.0352 *). The absolute lymphocyte count, LDL and free androgen index were the most significant individual markers, and combining the immune subsets with the metabolic markers into a biomarker ratio enhanced correlation with PFS (rs = −0.74; p ≤ 0.0001 ****). In summary, in addition to well-established markers, we identified PD-1+ monocytes and the free androgen index as potentially novel peripheral markers in the context of immunotherapy. Furthermore, the combination of immune subsets with metabolic and hormonal markers may have the potential to enhance the power of future predictive scores and should, therefore, be investigated further in larger trials.

Sex differences in monocyte CCR2 expression and macrophage polarization following acute exercise

Monocyte chemokine receptor 2 (CCR2) and phosphorylated extra-cellular regulated kinase 1 & 2 (ERK1/2) impact macrophage differentiation and progression of atherosclerosis. Whereas aerobic exercise favorably modulates the immune system and reduces atherosclerotic risk, it is unknown whether sex differences exist in the monocyte/macrophage response to acute aerobic exercise.

AIMS

To determine the impact of an acute bout of moderate intensity aerobic exercise on monocyte and macrophage CCR2 expression, ERK1/2 phosphorylation, and macrophage polarization in pre-menopausal women and men.

MATERIALS AND METHODS

Blood samples were collected in 24 people (Women/Men; n = 12) prior to (PRE), immediately after a bout of moderate intensity cycle ergometry (POST), and 2 h (2H) following exercise. Monocyte and macrophage CCR2 and phosphorylated ERK1/2 as well as macrophage CD86 and CD206 were analyzed by flow cytometry.

KEY FINDINGS

PRE classical monocyte CCR2 expression was greater in women compared to men (Women: 20546.2 ± 2306.4 vs. Men: 14437.6 ± 1201.9 AUF; p = 0.028) and was reduced in women at 2H (PRE: 20546.2 ± 2306.4 vs. 2H: 15856.9 ± 1314.4 AUF; p = 0.027). POST classical monocyte CCR2 expression was inversely associated (r = -0.697, p = 0.012) with POST classical monocyte ERK1/2 phosphorylation in women only. The percentage of CCR2⁺ macrophages was lower in women at POST (Women: 62.0 ± 8.9 vs. Men: 83.6 ± 3.1; p = 0.031) and at 2H (Women: 60.3 ± 8.4 vs. Men: 83.5 ± 3.0%; p = 0.016).

SIGNIFICANCE

These data suggest that a single bout of moderate intensity aerobic exercise differentially impacts monocyte CCR2 expression and macrophage polarization in women compared to men.

Intermediate Monocytes with PD-L1 and CD62L Expression as a Possible Player in Active SARS-CoV-2 Infection

Monocytes play a role in viral biology, but little is known about the monocyte subpopulation in the course of COVID-19 disease. The aim of the study was the analysis of classical, intermediate and non-classical monocytes with expression of PD-L1 and CD62L, TIM-3 and CD86 molecules in peripheral blood (PB) to distinguish patients with SARS-CoV-2 infection from convalescent patients. The study group consisted of 55 patients with SARS-CoV-2 infection and 51 convalescent patients. The cells were analyzed by flow cytometry. The number and proportion of monocytes were lower in patients with COVID-19 than convalescent patients. We observed a lower proportion of non-classical monocytes in COVID-19 patients than convalescent ones. There was a higher proportion of PDL-1-positive intermediate monocytes in COVID-19 patients than convalescent ones. We noticed a higher geometric mean fluorescence intensity (GeoMean) of PD-L1 on intermediate monocytes in COVID-19 patients than convalescent patients, and a higher proportion of CD62L-positive monocytes in COVID-19 patients in comparison with convalescent ones. We found a higher GeoMean of CD62L on monocytes in COVID-19 patients than convalescent ones. Assessment of PD-L1- and CD62L-positive monocyte subsets may identify patients with a possible predisposition for rapid recovery. The monitoring of monocyte subsets in PB might be a useful test in COVID-19 patients.

Capturing 3D Chromatin Maps of Human Primary Monocytes: Insights From High-Resolution Hi-C

Although the variation in chromatin architecture during adaptive immune responses has been thoroughly investigated, the 3D landscape of innate immunity is still unknown. Herein, chromatin regulation and heterogeneity among human primary monocytes were investigated. Peripheral blood was collected from two healthy persons and two patients with systemic lupus erythematosus (SLE), and CD14+ monocytes were selected to perform Hi-C, RNA-seq, ATAC-seq and ChIP-seq analyses. Raw data from the THP1 cell line Hi-C library were used for comparison. For each sample, we constructed three Hi-C libraries and obtained approximately 3 billion paired-end reads in total. Resolution analysis showed that more than 80% of bins presented depths greater than 1000 at a 5 kb resolution. The constructed high-resolution chromatin interaction maps presented similar landscapes in the four individuals, which showed significant divergence from the THP1 cell line chromatin structure. The variability in chromatin interactions around HLA-D genes in the HLA complex region was notable within individuals. We further found that the CD16-encoding gene (FCGR3A) is located at a variable topologically associating domain (TAD) boundary and that chromatin loop dynamics might modulate CD16 expression. Our results indicate both the stability and variability of high-resolution chromatin interaction maps among human primary monocytes. This work sheds light on the potential mechanisms by which the complex interplay of epigenetics and spatial 3D architecture regulates chromatin in innate immunity.

Systemic Influences of Mammary Cancer on Monocytes in Mice

There is a growing body of evidence that cancer causes systemic changes. These influences are most evident in the bone marrow and the blood, particularly in the myeloid compartment. Here, we show that there is an increase in the number of bone marrow, circulating and splenic monocytes by using mouse models of breast cancer caused by the mammary epithelial expression of the polyoma middle T antigen. Cancer does not affect ratios of classical to non-classical populations of monocytes in the circulation nor does it affect their half-lives. Single cell RNA sequencing also indicates that cancer does not induce any new monocyte populations. Cancer does not change the monocytic progenitor number in the bone marrow, but the proliferation rate of monocytes is higher, thus providing an explanation for the expansion of the circulating numbers. Deep RNA sequencing of these monocytic populations reveals that cancer causes changes in the classical monocyte compartment, with changes evident in bone marrow monocytes and even more so in the blood, suggesting influences in both compartments, with the down-regulation of interferon type 1 signaling and antigen presentation being the most prominent of these. Consistent with this analysis, down-regulated genes are enriched with STAT1/STAT2 binding sites in their promoter, which are transcription factors required for type 1 interferon signaling. However, these transcriptome changes in mice did not replicate those found in patients with breast cancer. Consequently, this mouse model of breast cancer may be insufficient to study the systemic influences of human cancer.

Atherosclerosis: nexus of vascular dynamics and cellular cross talks

Cardiovascular diseases (CVDs) are the foremost cause of mortality worldwide. Atherosclerosis is the underlying pathology behind CVDs. Atherosclerosis is manifested predominantly by lipid deposition, plaque formation, and inflammation in vascular intima. Initiation and progression of plaque require many years. With aging, atherosclerotic plaques become vulnerable. Localization of these plaques in the coronary artery leads to myocardial infarction. A complete understanding of the pathophysiology of this multifaceted disease is necessary to achieve the clinical goal to provide early diagnosis and the best therapeutics. The triggering factors of atherosclerosis are biomechanical forces, hyperlipidemia, and chronic inflammatory response. The current review focuses on crucial determinants involved in the disease, such as location, hemodynamic factors, oxidation of low-density lipoproteins, and the role of endothelial cells, vascular smooth muscle cells, and immune cells, and better therapeutic targets.

Phenotypic and Functional Heterogeneity of Monocyte Subsets in Chronic Heart Failure Patients

Chronic heart failure (CHF) results when the heart cannot consistently supply the body's tissues with oxygen and required nutrients. CHF can be categorized as heart failure (HF) with preserved ejection fraction (HFpEF) or HF with reduced ejection fraction (HFrEF). There are different causes and mechanisms underlying HF pathogenesis; however, inflammation can be regarded as one of the factors that promotes both HFrEF and HFpEF. Monocytes, a subgroup of leukocytes, are known to be cellular mediators in response to cardiovascular injury and are closely related to inflammatory reactions. These cells are a vital component of the immune system and are the source of macrophages, which participate in cardiac tissue repair after injury. However, these monocytes are not as homogenous as thought and can present different functions under different cardiovascular disease conditions. In addition, there is still an open question regarding whether the functions of monocytes and macrophages should be regarded as causes or consequences in CHF development. Therefore, the aim of this work was to summarize current studies on the functions of various monocyte subsets in CHF with a focus on the role of a certain monocyte subset in HFpEF and HFrEF patients, as well as the subsets' relationship to inflammatory markers.

The Role of miRNA in Regulating the Fate of Monocytes in Health and Cancer

Monocytes represent a heterogeneous population of blood cells that provide a link between innate and adaptive immunity. The unique potential of monocytes as both precursors (e.g., of macrophages) and effector cells (as phagocytes or cytotoxic cells) makes them an interesting research and therapeutic target. At the site of a tumor, monocytes/macrophages constitute a major population of infiltrating leukocytes and, depending on the type of tumor, may play a dual role as either a bad or good indicator for cancer recovery. The functional activity of monocytes and macrophages derived from them is tightly regulated at the transcriptional and post-transcriptional level. This review summarizes the current understanding of the role of small regulatory miRNA in monocyte formation, maturation and function in health and cancer development. Additionally, signatures of miRNA-based monocyte subsets and the influence of exogenous miRNA generated in the tumor environment on the function of monocytes are discussed.

Innate immune cells in the pathophysiology of calcific aortic valve disease: lessons to be learned from atherosclerotic cardiovascular disease?

Calcific aortic valve disease (CAVD) is the most common valvular disease in the developed world with currently no effective pharmacological treatment available. CAVD results from a complex, multifactorial process, in which valvular inflammation and fibro-calcific remodelling lead to valve thickening and cardiac outflow obstruction. The exact underlying pathophysiology of CAVD is still not fully understood, yet the development of CAVD shows many similarities with the pathophysiology of atherosclerotic cardiovascular disease (ASCVD), such as coronary artery disease. Innate immune cells play a crucial role in ASCVD and might also play a pivotal role in the development of CAVD. This review summarizes the current knowledge on the role of innate immune cells, both in the circulation and in the aortic valve, in the development of CAVD and the similarities and differences with ASCVD. Trained immunity and clonal haematopoiesis of indeterminate potential are proposed as novel immunological mechanisms that possibly contribute to the pathophysiology of CAVD and new possible treatment targets are discussed.

MEK inhibition exerts temporal and myeloid cell-specific effects in the pathogenesis of neurofibromatosis type 1 arteriopathy

Mutations in the NF1 tumor suppressor gene are linked to arteriopathy. Nf1 heterozygosity (Nf1+/–) results in robust neointima formation, similar to humans, and myeloid-restricted Nf1+/– recapitulates this phenotype via MEK-ERK activation. Here we define the contribution of myeloid subpopulations to NF1 arteriopathy. Neutrophils from WT and Nf1+/– mice were functionally assessed in the presence of MEK and farnesylation inhibitors in vitro and neutrophil recruitment to lipopolysaccharide was assessed in WT and Nf1+/– mice. Littermate 12–15 week-old male wildtype and Nf1+/– mice were subjected to carotid artery ligation and provided either a neutrophil depleting antibody (1A8), liposomal clodronate to deplete monocytes/macrophages, or PD0325901 and neointima size was assessed 28 days after injury. Bone marrow transplant experiments assessed monocyte/macrophage mobilization during neointima formation. Nf1+/– neutrophils exhibit enhanced proliferation, migration, and adhesion via p21^Ras activation of MEK in vitro and in vivo. Neutrophil depletion suppresses circulating Ly6C^low monocytes and enhances neointima size, while monocyte/macrophage depletion and deletion of CCR2 in bone marrow cells abolish neointima formation in Nf1+/– mice. Taken together, these findings suggest that neurofibromin-MEK-ERK activation in circulating neutrophils and monocytes during arterial remodeling is nuanced and points to important cross-talk between these populations in the pathogenesis of NF1 arteriopathy.

COVID-19, what could sepsis, severe acute pancreatitis, gender differences, and aging teach us?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a potentially life-threatening disease, defined as Coronavirus Disease 19 (COVID-19). The most common signs and symptoms of this pathological condition include cough, fever, shortness of breath, and sudden onset of anosmia, ageusia, or dysgeusia. The course of COVID-19 is mild or moderate in more than 80% of cases, but it is severe or critical in about 14% and 5% of infected subjects respectively, with a significant risk of mortality. SARS-CoV-2 related infection is characterized by some pathogenetic events, resembling those detectable in other pathological conditions, such as sepsis and severe acute pancreatitis. All these syndromes are characterized by some similar features, including the coexistence of an exuberant inflammatory- as well as an anti-inflammatory-response with immune depression. Based on current knowledge concerning the onset and the development of acute pancreatitis and sepsis, we have considered these syndromes as a very interesting paradigm for improving our understanding of pathogenetic events detectable in patients with COVID-19. The aim of our review is: 1)to examine the pathogenetic mechanisms acting during the emergence of inflammatory and anti-inflammatory processes in human pathology; 2)to examine inflammatory and anti-inflammatory events in sepsis, acute pancreatitis, and SARS-CoV-2 infection and clinical manifestations detectable in patients suffering from these syndromes also according to the age and gender of these individuals; as well as to analyze the possible common and different features among these pathological conditions; 3)to obtain insights into our knowledge concerning COVID-19 pathogenesis. This approach may improve the management of patients suffering from this disease and it may suggest more effective diagnostic approaches and schedules of therapy, depending on the different phases and/or on the severity of SARS-CoV-2 infection.

The Association of Circulating CD14++CD16+ Monocytes, Natural Killer Cells and Regulatory T Cells Subpopulations With Phenotypes of Cardiovascular Disease in a Cohort of Peritoneal Dialysis Patients

The altered expression of immune cells including monocyte subsets, natural killer (NK) cells and CD4+CD25+ regulatory T cells (Tregs) in end-stage kidney disease, affect the modulation of inflammation and immunity with significant clinical implications. The aim of this study was to investigate the profile of specific immune cells subpopulations and their correlations with phenotypes of established cardiovascular disease (CVD), including coronary artery disease (CAD) and heart failure (HF) in peritoneal dialysis (PD) patients.

Materials and Methods: 29 stable PD patients and 13 healthy volunteers were enrolled. Demographic, laboratory, bioimpedance measurements, lung ultrasound and echocardiography data were collected. The peripheral blood immune cell subsets analysis was performed using flow cytometry.

Results: PD patients compared to normal controls had lower total lymphocytes (22.3 ± 6.28 vs. 31.3 ± 5.54%, p = <0.001) and B-lymphocytes (6.39 ± 3.75 vs. 9.72 ± 3.63%, p = 0.01) as well as higher CD14++CD16+ monocytes numbers (9.28 ± 6.36 vs. 4.75 ± 2.75%, p = 0.0002). PD patients with prevalent CAD had NK cells levels elevated above median values (85.7 vs. 40.9%, p = 0.04) and lower B cells counts (3.85 ± 2.46 vs. 7.2 ± 3.77%, p = 0.03). Patients with increased NK cells (>15.4%) had 3.8 times higher risk of CAD comparing with patients with lower NK cell levels (95% CI, 1.86 – 77.87; p = 0.034). B cells were inversely associated with the presence of CAD (increase of B-lymphocyte by 1% was associated with 30% less risk for presence of CAD (95% CI, −0.71 – 0.01; p = 0.05). Overhydrated patients had lower lymphocytes counts (18.3 ± 4.29% vs. 24.7 ± 6.18%, p = 0.006) and increased NK cells [20.5% (14.3, 23.6) vs. 13.21% (6.23, 19.2), p = 0.04)]. In multiple logistic regression analysis the CRP (OR 1.43; 95% CI, 1.00 – 2.05; p = 0.04)] and lymphocytes counts (OR 0.79; 95% CI, 0.63–0.99; p = 0.04)] were associated with the presence of lung comets. Patients with higher NK cells (>15.4%, n = 15) were more likely to be rapid transporters (D/P creatinine 0.76 ± 0.1 vs. 0.69 ± 0.08, p = 0.04). Patients displaying higher Tregs (>1.79%) were older (70.8 ± 10.7 years vs. 57.7 ± 14.7years, p = 0.011) and had higher nPCR (0.83 ± 0.14 vs. 0.91 ± 0.17, p = 0.09).

Conclusion: Future research is required to evaluate the role of immune cells subsets as potential tools to identify patients at the highest risk for complications and guide interventions.

Severe Traumatic Injury Induces Phenotypic and Functional Changes of Neutrophils and Monocytes

Background: Severe traumatic injury has been associated with high susceptibility for the development of secondary complications caused by dysbalanced immune response. As the first line of the cellular immune response, neutrophils and monocytes recruited to the site of tissue damage and/or infection, are divided into three different subsets according to their CD16/CD62L and CD16/CD14 expression, respectively. Their differential functions have not yet been clearly understood. Thus, we evaluated the phenotypic changes of neutrophil and monocyte subsets among their functionality regarding oxidative burst and the phagocytic capacity in severely traumatized patients. Methods: Peripheral blood was withdrawn from severely injured trauma patients (TP; n = 15, ISS ≥ 16) within the first 12 h post-trauma and from healthy volunteers (HV; n = 15) and stimulated with fMLP and PMA. CD16^dimCD62L^bright (immature), CD16^brightCD62L^bright (mature) and CD16^brightCD62L^dim (CD62L^low) neutrophil subsets and CD14^brightCD16⁻ (classical), CD14^brightCD16⁺ (intermediate) and CD14^dimCD16⁺ (non-classical) monocyte subsets of HV and TP were either directly analyzed by flow cytometry or the examined subsets of HV were sorted first by fluorescence-activated cell sorting and subsequently analyzed. Subset-specific generation of reactive oxygen species (ROS) and of E. coli bioparticle phagocytosis were evaluated. Results: In TP, the counts of immature neutrophils were significantly increased vs. HV. The numbers of mature and CD62L^dim neutrophils remained unchanged but the production of ROS was significantly enhanced in TP vs. HV and the stimulation with fMLP significantly increased the generation of ROS in the mature and CD62L^dim neutrophils of HV. The counts of phagocyting neutrophils did not change but the mean phagocytic capacity showed an increasing trend in TP. In TP, the monocytes shifted toward the intermediate phenotype, whereas the classical and non-classical monocytes became less abundant. ROS generation was significantly increased in all monocyte subsets in TP vs. HV and PMA stimulation significantly increased those level in both, HV and TP. However, the PMA-induced mean ROS generation was significantly lower in intermediate monocytes of TP vs. HV. Sorting of monocyte and neutrophil subsets revealed a significant increase of ROS and decrease of phagocytic capacity vs. whole blood analysis. Conclusions: Neutrophils and monocytes display a phenotypic shift following severe injury. The increased functional abnormalities of certain subsets may contribute to the dysbalanced immune response and attenuate the antimicrobial function and thus, may represent a potential therapeutic target. Further studies on isolated subsets are necessary for evaluation of their physiological role after severe traumatic injury.

Low-dose interferon-alpha preconditioning and adoptive cell therapy in patients with metastatic melanoma refractory to standard (immune) therapies: a phase I/II study

BACKGROUND

Adoptive cell therapy (ACT) with tumor-reactive T cells has shown consistent clinical efficacy. We evaluated the response to ACT in combination with interferon alpha (IFNa) preconditioning in patients with stage IV metastatic melanoma, most of which were progressive on cytotoxic T-lymphocyte-associated protein 4 and/or programmed cell death protein 1 checkpoint blockade therapy.

METHODS

Thirty-four patients were treated with ex vivo expanded tumor reactive T cells, derived from mixed lymphocyte autologous tumor cultures, or with autologous tumor-infiltrating lymphocytes and evaluated for clinical response. Clinical and immunological parameters associated with response were also evaluated.

RESULTS

Best overall response defined as clinical benefit, comprising either complete response, partial response or stable disease >6 months, was observed in 29% of the patients. Forty-three per cent of the 14 immunotherapy-naïve patients and 20% of the 20 patients progressive on prior immunotherapy benefited from ACT. The overall survival (OS) was 90% versus 28.6% at 1 year and 46.7% versus 0% at 3 years follow-up, of responder and non-responder patients, respectively. Median OS was 36 versus 7 months, respectively. IFNa pretreatment resulted in leukopenia, neutropenia and lymphopenia, which was sustained during the treatment in clinical responders and associated with response. Differences in antigen specificity, but not in phenotype, cytokine profile or CD8+ T cell number of the ACT products correlated with clinical response. Cross-reactivity of the ACT products to one or more allogeneic human leukocyte antigen-matched melanoma cell lines was associated with short OS after treatment while the ACT products of very long-term survivors showed no cross-reactivity but recognized patient-specific neoantigens.

CONCLUSION

This study demonstrates that ACT in combination with a mild IFNa preconditioning regimen can induce clinical benefit even in immunotherapy pretreated patients, although with lower success than in immunotherapy-naïve patients. ACT products comprising neoantigen reactivity may be more effective.

Monocyte CD14 and HLA-DR expression increases with disease duration and severity in amyotrophic lateral sclerosis

Objective: To investigate changes in immune markers and frequencies throughout disease progression in patients with amyotrophic lateral sclerosis (ALS). Methods: In this longitudinal study, serial blood samples were collected from 21 patients with ALS over a time period of up to 16 months. Flow cytometry was used to quantitate CD14, HLA-DR, and CD16 marker expression on monocyte subpopulations and neutrophils, as well as their cell population frequencies. A Generalized Estimating Equation model was used to assess the association between changes in these immune parameters and disease duration and the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R). Results: CD14 expression on monocyte subpopulations increased with both disease duration and a decrease in ALSFRS-R score in patients with ALS. HLA-DR expression on monocyte subpopulations also increased with disease severity and/or duration. The expression of CD16 did not change relative to disease duration or ALSFRS-R. Finally, patients had a reduction in non-classical monocytes and an increase in the classical to non-classical monocyte ratio throughout disease duration. Conclusion: The progressive immunological changes observed in this study provide further support that monocytes are implicated in ALS pathology. Monocytic CD14 and HLA-DR surface proteins may serve as a therapeutic target or criteria for the recruitment of patients with ALS into clinical trials for immunomodulatory therapies.

Monocyte Dysfunction Detected by the Designed Ankyrin Repeat Protein F7 Predicts Mortality in Patients Receiving Veno-Arterial Extracorporeal Membrane Oxygenation

Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used for critically ill patients requiring hemodynamic support but has been shown to induce an inflammatory response syndrome potentially leading to severe complications and poor outcome. Monocytes are comprised of different subsets and play a central role in the innate immune system. The unique small binding proteins, Designed Ankyrin Repeat Protein “F7” and single chain variable fragment “MAN-1,” specifically detect the activated conformation of the leukocyte integrin Mac-1 enabling the highly sensitive detection of monocyte activation status. The aim of this study was to characterize monocyte function and heterogeneity and their association with outcome in VA-ECMO patients.

Methods: VA-ECMO patients were recruited from the ICUs of the University Hospital in Freiburg, Germany. Blood was sampled on day 0 and day 3 after VA-ECMO placement, after VA-ECMO explantation and from healthy controls. Monocyte subset distribution, baseline activation and stimulability were analyzed by flow cytometry using the unique small binding proteins F7 and MAN-1 and the conventional activation markers CD163, CD86, CD69, and CX3CR1. Furthermore, expression of monocyte activation markers in survivors and non-survivors on day 0 was compared. Simple logistic regression was conducted to determine the association of monocyte activation markers with mortality.

Results: Twenty two patients on VA-ECMO and 15 healthy controls were recruited. Eleven patients survived until discharge from the ICU. Compared to controls, baseline monocyte activation was significantly increased, whereas stimulability was decreased. The percentage of classical monocytes increased after explantation, while the percentage of intermediate monocytes decreased. Total, classical, and intermediate monocyte counts were significantly elevated compared to controls. On day 0, baseline binding of F7 was significantly lower in non-survivors than survivors. The area under the ROC curve associated with mortality on day 0 was 0.802 (p = 0.02).

Conclusions: Distribution of monocyte subsets changes during VA-ECMO and absolute classical and intermediate monocyte counts are significantly elevated compared to controls. Monocytes from VA-ECMO patients showed signs of dysfunction. Monocyte dysfunction, as determined by the unique tool F7, could be valuable for predicting mortality in patients receiving VA-ECMO and may be used as a novel biomarker guiding early clinical decision making in the future.

The Innate Immune System and Cardiovascular Disease in ESKD: Monocytes and Natural Killer Cells

Adverse innate immune responses have been implicated in several disease processes, including cardiovascular disease (CVD) and chronic kidney disease (CKD). The monocyte subsets natural killer (NK) cells and natural killer T (NKT) cells are involved in innate immunity. Monocytes subsets are key in atherogenesis and the inflammatory cascade occurring in heart failure. Upregulated activity and counts of proinflammatory CD16+ monocyte subsets are associated with clinical indices of atherosclerosis, heart failure syndromes and CKD. Advanced CKD is a complex state of persistent systemic inflammation characterized by elevated expression of proinflammatory and pro-atherogenic CD14++CD16+ monocytes, which are associated with cardiovascular events and death both in the general population and among patients with CKD. Diminished NK cells and NKT cells counts and aberrant activity are observed in both coronary artery disease and end-stage kidney disease. However, evidence of the roles of NK cells and NKT cells in atherogenesis in advanced CKD is circumstantial and remains to be clarified. This review describes the available evidence regarding the roles of specific immune cell subsets in the pathogenesis of CVD in patients with CKD. Future research is expected to further uncover the links between CKD associated innate immune system dysregulation and accelerated CVD and will ideally be translated into therapeutic targets.

Assessing single-cell transcriptomic variability through density-preserving data visualization

Nonlinear data visualization methods, such as t-distributed stochastic neighbor embedding (t-SNE) and uniform manifold approximation and projection (UMAP), summarize the complex transcriptomic landscape of single cells in two dimensions or three dimensions, but they neglect the local density of data points in the original space, often resulting in misleading visualizations where densely populated subsets of cells are given more visual space than warranted by their transcriptional diversity in the dataset. Here we present den-SNE and densMAP, which are density-preserving visualization tools based on t-SNE and UMAP, respectively, and demonstrate their ability to accurately incorporate information about transcriptomic variability into the visual interpretation of single-cell RNA sequencing data. Applied to recently published datasets, our methods reveal significant changes in transcriptomic variability in a range of biological processes, including heterogeneity in transcriptomic variability of immune cells in blood and tumor, human immune cell specialization and the developmental trajectory of Caenorhabditis elegans. Our methods are readily applicable to visualizing high-dimensional data in other scientific domains.

Tumor Necrosis Factor-α Blockade Corrects Monocyte/Macrophage Imbalance in Primary Immune Thrombocytopenia

Primary immune thrombocytopenia (ITP) is an acquired autoimmune bleeding disorder. Monocytes and macrophages are the major cells involved in autoantibody-mediated platelet clearance in ITP. In the present study, we found increased percentages of peripheral blood proinflammatory CD16+ monocytes and elevated frequencies of splenic tumor necrosis factor-α (TNF-α)-expressing macrophages in ITP patients compared with healthy controls. Concurrently, we observed elevated TNF-α secretion in plasma as well as higher TNF-α mRNA expression in total peripheral blood mononuclear cells and CD14+ monocytes of ITP patients. Of note, in vitro TNF-α blockade with neutralizing antibody remarkably reduced polarization to M1 macrophages by inhibiting the nuclear factor kappa B (NF-κB) signaling pathway. Moreover, TNF-α blockade dampened macrophage phagocytosis and T cell stimulatory capacity. Finally, in passive and active murine models of ITP, anti-TNF-α therapy reduced the number of nonclassical monocytes and M1 macrophages, ameliorated the retention of platelets in spleen and liver, and increased the platelet count of ITP mice. Taken together, TNF-α blockade decreased the number and function of proinflammatory subsets of monocytes and macrophages by inhibiting the NF-κB signaling pathway, leading to remarkable attenuation of antibody-mediated platelet destruction. Thus, TNF-α blockade may be a promising therapeutic strategy for the management of ITP.

Novel Immune Cell Subsets Exhibit Different Associations With Vascular Outcomes in Chronic Kidney Disease Patients-Identifying Potential Biomarkers

Background and Aims: Alterations in novel immune cell subsets, such as angiogenic T cells (Tang), senescent T cells (CD4⁺CD28^null), and monocyte subsets are associated with impaired vascular homeostasis in several inflammatory conditions. However, mediators underlying vascular deterioration in chronic kidney disease (CKD) are poorly characterized. This study assessed their role in the vascular deterioration of CKD using a broad spectrum of surrogate markers ranging from altered functionality to overt calcification.

Methods: Tang (CD3⁺CD31⁺CXCR4⁺), CD4⁺CD28^null cells, and monocytes [CD14/CD16 subsets and angiotensin-converting enzyme (ACE) expression] were measured in peripheral blood by flow cytometry in 33 CKD stage 5 patients undergoing peritoneal dialysis (CKD5-PD) and 15 healthy controls (HCs). Analyses were replicated in a hemodialysis cohort. Vascular surrogate markers (including adventitial vasa vasorum, pulse wave velocity, intima-media thickness, and vascular calcification) were assessed by appropriate imaging methods.

Results: In CKD5-PD, decreased Tang levels (p < 0.001) were unrelated to clinical features or traditional cardiovascular (CV) risk factors but correlated negatively with troponin T levels (r = −0.550, p = 0.003). Instead, CD4⁺CD28^null frequency was increased (p < 0.001), especially in those with vascular calcifications. Quantitative and qualitative differences were also observed within the monocyte pool, a shift toward CD16⁺ subsets and ACE expression being found in CKD. Equivalent results were observed in the replication cohort. Each subset associated distinctly with adverse vascular outcomes in univariate and multivariate analyses: while Tang depletion was linked to poor vascular function and subclinical atherosclerosis, increases in CD4⁺CD28^null were associated with overt vascular thickening and calcification. Monocytes were not independently associated with vascular outcomes in CKD patients.

Conclusions: Novel T cell and monocyte subsets are altered in CKD. Altered T-cell subpopulations, but not monocytes, exhibited distinct associations with different vascular outcomes in CKD. Tang are emerging biomarkers of subclinical vascular deterioration in CKD.

Multicohort Analysis Identifies Monocyte Gene Signatures to Accurately Monitor Subset-Specific Changes in Human Diseases

Monocytes are crucial regulators of inflammation, and are characterized by three distinct subsets in humans, of which classical and non-classical are the most abundant. Different subsets carry out different functions and have been previously associated with multiple inflammatory conditions. Dissecting the contribution of different monocyte subsets to disease is currently limited by samples and cohorts, often resulting in underpowered studies and poor reproducibility. Publicly available transcriptome profiles provide an alternative source of data characterized by high statistical power and real-world heterogeneity. However, most transcriptome datasets profile bulk blood or tissue samples, requiring the use of in silico approaches to quantify changes in cell levels. Here, we integrated 853 publicly available microarray expression profiles of sorted human monocyte subsets from 45 independent studies to identify robust and parsimonious gene expression signatures, consisting of 10 genes specific to each subset. These signatures maintain their accuracy regardless of disease state in an independent cohort profiled by RNA-sequencing and are specific to their respective subset when compared to other immune cells from both myeloid and lymphoid lineages profiled across 6160 transcriptome profiles. Consequently, we show that these signatures can be used to quantify changes in monocyte subsets levels in expression profiles from patients in clinical trials. Finally, we show that proteins encoded by our signature genes can be used in cytometry-based assays to specifically sort monocyte subsets. Our results demonstrate the robustness, versatility, and utility of our computational approach and provide a framework for the discovery of new cellular markers.

Ex vivo expansion of dysfunctional regulatory T lymphocytes restores suppressive function in Parkinson's disease

Inflammation is a pathological hallmark of Parkinson's disease (PD). Chronic pro-inflammatory responses contribute to the loss of neurons in the neurodegenerative process. The present study was undertaken to define the peripheral innate and adaptive immune contributions to inflammation in patients with PD. Immunophenotyping revealed a shift of peripheral myeloid and lymphoid cells towards a pro-inflammatory phenotype. Regulatory T cells (Tregs) were reduced in number, and their suppression of T responder proliferation decreased. The PD Tregs did not suppress activated pro-inflammatory myeloid cells. Ex vivo expansion of Tregs from patients with PD restored and enhanced their suppressive functions while expanded Tregs displayed increased expression of foxp3, il2ra (CD25), nt5e (CD73), il10, il13, ctla4, pdcd1 (PD1), and gzmb. Collectively, these findings documented a shift towards a pro-inflammatory peripheral immune response in patients with PD; the loss of Treg suppressive functions may contribute significantly to this response, supporting PD as a disorder with extensive systemic pro-inflammatory responses. The restoration and enhancement of Treg suppressive functions following ex vivo expansion may provide a potential cell therapeutic approach for patients with PD.

PD-1+ Monocytes Mediate Cerebral Vasospasm Following Subarachnoid Hemorrhage

BACKGROUND

Cerebral vasospasm is a major source of morbidity and mortality following aneurysm rupture and has limited treatment options.

OBJECTIVE

To evaluate the role of programmed death-1 (PD-1) in cerebral vasospasm.

METHODS

Endovascular internal carotid artery perforation (ICAp) was used to induce cerebral vasospasm in mice. To evaluate the therapeutic potential of targeting PD-1, programmed death ligand-1 (PD-L1) was administered 1 h after ICAp and vasospasm was measured histologically at the level of the ICA bifurcation bilaterally. PD-1 expressing immune cell populations were evaluated by flow cytometry. To correlate these findings to patients and evaluate the potential of PD-1 as a biomarker, monocytes were isolated from the peripheral blood and analyzed by flow cytometry in a cohort of patients with ruptured cerebral aneurysms. The daily frequency of PD-1+ monocytes in the peripheral blood was correlated to transcranial Doppler velocities as well as clinical and radiographic vasospasm.

RESULTS

We found that PD-L1 administration prevented cerebral vasospasm by inhibiting ingress of activated Ly6c+ and CCR2+ monocytes into the brain. Human correlative studies confirmed the presence of PD-1+ monocytes in the peripheral blood of patients with ruptured aneurysms and the frequency of these cells corresponded with cerebral blood flow velocities and clinical vasospasm.

CONCLUSION

Our results identify PD-1+ monocytes as mediators of cerebral vasospasm and support PD-1 agonism as a novel therapeutic strategy.

Viral infection and allergy - What equine immune responses can tell us about disease severity and protection

Horses have many naturally occurring diseases that mimic similar conditions in humans. The ability to conduct environmentally controlled experiments and induced disease studies in a genetically diverse host makes the horse a valuable intermediate model between mouse studies and human clinical trials. This review highlights important similarities in the immune landscape between horses and humans using current research on two equine diseases as examples. First, equine herpesvirus type 1 (EHV-1) infection initiates a series of innate inflammatory signals at its mucosal entry site in the upper respiratory tract. These inflammatory markers are highly synchronized and predictable between individuals during viral respiratory infection and ultimately lead to adaptive immune induction and protection. The timing of early inflammatory signals, followed by specific adaptive immune markers correlating with immunity and protection, allow accurate outbreak tracking and also provide a foundation for understanding the importance of local mucosal immunity during other viral respiratory infections. Second, rare peripheral blood immune cells that promote allergic inflammation can be analyzed during Culicoides hypersensitivity, a naturally occurring type I IgE-mediated allergic disease of horses. Rare immune cells, such as IgE-binding monocytes or basophils, can be studied repeatedly in the horse model to unravel their larger mechanistic role in inflammation during allergic and other inflammatory diseases. We conclude with a survey of all other common equine inflammatory conditions. Together, this review serves as a reference and rationale for the horse as a non-rodent model for immunological research.

IgE-Binding Monocytes Have an Enhanced Ability to Produce IL-8 (CXCL8) in Animals with Naturally Occurring Allergy

IL-8 is a potent chemokine that recruits neutrophils and basophils to promote inflammation in many species. IL-8 is produced by many cell types, including monocytes. In this study, we report a novel role for IgE-binding monocytes, a rare peripheral immune cell type, to promote allergic inflammation through IL-8 production in a horse model of natural IgE-mediated allergy. We developed a mAb with confirmed specificity for both recombinant and native equine IL-8 for flow cytometric analysis. Equine IL-8 was produced by CD14⁺/MHC class II⁺/CD16^- monocytes, including a subpopulation of IgE-binding monocytes, following stimulation with LPS. In addition, IgE cross-linking induced IL-8 production by both peripheral blood basophils and IgE-binding monocytes. IL-8 production was compared between healthy horses and those with a naturally occurring IgE-mediated skin allergy, Culicoides hypersensitivity. Allergic horses had significantly higher percentages of IL-8⁺ IgE-binding monocytes after IgE cross-linking. In contrast, frequencies of IL-8⁺ basophils after IgE cross-linking were similar in all horses, regardless of allergic disease, highlighting IgE-binding monocytes as a novel source of IL-8 during allergy. We concluded that IgE-binding monocytes from allergic individuals have an increased capacity for IL-8 production and likely contribute to the recruitment of innate immune cells during IgE-mediated allergy and promotion of inflammation during repeated allergen contact.

Leukocytes from Patients with Drug-Sensitive and Multidrug-Resistant Tuberculosis Exhibit Distinctive Profiles of Chemokine Receptor Expression and Migration Capacity

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains as a leading infectious cause of death worldwide. The increasing number of multidrug-resistant TB (MDR-TB) cases contributes to the poor control of the TB epidemic. Currently, little is known about the immunological requirements of protective responses against MDR-TB. This is of major relevance to identify immune markers for treatment monitoring and targets for adjuvant immunotherapies. Here, we hypothesized that MDR-TB patients display unique immunophenotypical features and immune cell migration dynamics compared to drug-sensitive TB (DS-TB). Hence, we prospectively conducted an extensive characterization of the immune profile of MDR-TB patients at different time points before and after pharmacological therapy. For this purpose, we focused on the leukocyte expression of chemokine receptors, distribution of different monocyte and lymphocyte subsets, plasma levels of chemotactic factors, and in vitro migration capacity of immune cells. Our comparative cohort consisted of DS-TB patients and healthy volunteer donors (HD). Our results demonstrate some unique features of leukocyte migration dynamics during MDR-TB. These include increased and prolonged circulation of CD3+ monocytes, CCR4+ monocytes, EM CD4+ T cells, EM/CM CD8+ T cells, and CXCR1+CXCR3+ T cells that is sustained even after the administration of anti-TB drugs. We also observed shared characteristics of both MDR-TB and DS-TB that include CCR2+ monocyte depletion in the blood; high plasma levels of MPC-1, CCL-7, and IP-10; and increased responsiveness of leukocytes to chemotactic signals in vitro. Our study contributes to a better understanding of the MDR-TB pathobiology and uncovers immunological readouts of treatment efficacy.

Immune and vascular contributions to organogenesis of the testis and ovary

Gonad development is a highly regulated process that coordinates cell specification and morphogenesis to produce sex-specific organ structures that are required for fertility, such as testicular seminiferous tubules and ovarian follicles. While sex determination occurs within specialized gonadal supporting cells, sexual differentiation is evident throughout the entire organ, including within the interstitial compartment, which contains immune cells and vasculature. While immune and vascular cells have been traditionally appreciated for their supporting roles during tissue growth and homeostasis, an increasing body of evidence supports the idea that these cell types are critical drivers of sexually dimorphic morphogenesis of the gonad. Myeloid immune cells, such as macrophages, are essential for multiple aspects of gonadogenesis and fertility, including for forming and maintaining gonadal vasculature in both sexes at varying stages of life. While vasculature is long known for supporting organ growth and serving as an export mechanism for gonadal sex steroids in utero, it is also an important component of fetal testicular morphogenesis and differentiation; additionally, it is vital for ovarian corpus luteal function and maintenance of pregnancy. These findings point toward a new paradigm in which immune cells and blood vessels are integral components of sexual differentiation and organogenesis. In this review, we discuss the state of the field regarding the diverse roles of immune and vascular cells during organogenesis of the testis and ovary and highlight outstanding questions in the field that could stimulate new research into these previously underappreciated constituents of the gonad.

Monocyte Subset Recruitment Marker Profile Is Inversely Associated With Blood ApoA1 Levels

Dyslipidemia promotes development of the atherosclerotic plaques that characterise cardiovascular disease. Plaque progression requires the influx of monocytes into the vessel wall, but whether dyslipidemia is associated with an increased potential of monocytes to extravasate is largely unknown. Here (using flow cytometry) we examined recruitment marker expression on monocytes from generally healthy individuals who differed in lipid profile. Comparisons were made between monocyte subsets, participants and relative to participants’ lipid levels. Monocyte subsets differed significantly in their expression of recruitment markers, with highest expression being on either the classical or non-classical subsets. However, these inter-subset differences were largely overshadowed by considerable inter-participant differences with some participants having higher levels of recruitment markers on all three monocyte subsets. Furthermore, when the expression of one recruitment marker was high, so too was that of most of the other markers, with substantial correlations evident between the markers. The inter-participant differences were explained by lipid levels. Most notably, there was a significant inverse correlation for most markers with ApoA1 levels. Our results indicate that dyslipidemia, in particular low levels of ApoA1, is associated with an increased potential of all monocyte subsets to extravasate, and to do so using a wider repertoire of recruitment markers than currently appreciated.

Monocyte Regulation in Homeostasis and Malignancy

Monocytes are progenitors to macrophages and a subclass of dendritic cells (monocyte-derived dendritic cells, MoDCs), but they also act as circulating sensors that respond to environmental changes and disease. Technological advances have defined the production of classical monocytes in the bone marrow through the identification of lineage-determining transcription factors (LDTFs) and have proposed alternative routes of differentiation. Monocytes released into the circulation can be recruited to tissues by specific chemoattractants where they respond to sequential niche-specific signals that determine their differentiation into terminal effector cells. New aspects of monocyte biology in the circulation are being revealed, exemplified by the influence of cancer on the systemic alteration of monocyte subset abundance and transcriptional profiles. These changes can act to enhance the metastatic spread of primary cancers and may offer therapeutic opportunities.

Recent Advances in Camel Immunology

Camels are domesticated animals that are highly adapted to the extreme desert ecosystem with relatively higher resistance to a wide range of pathogens compared to many other species from the same geographical region. Recently, there has been increased interest in the field of camel immunology. As the progress in the analysis of camel immunoglobulins has previously been covered in many recent reviews, this review intends to summarize published findings related to camel cellular immunology with a focus on the phenotype and functionality of camel leukocyte subpopulations. The review also describes the impact of different physiological (age and pregnancy) and pathological (e.g. infection) conditions on camel immune cells. Despite the progress achieved in the field of camel immunology, there are gaps in our complete understanding of the camel immune system. Questions remain regarding innate recognition mechanisms, the functional characterization of antigen-presenting cells, and the characterization of camel NK and cytotoxic T cells.

Deciphering the complex circulating immune cell microenvironment in chronic lymphocytic leukaemia using patient similarity networks

The tissue microenvironment in chronic lymphocytic leukaemia (CLL) plays a key role in the pathogenesis of CLL, but the complex blood microenvironment in CLL has not yet been fully characterised. Therefore, immunophenotyping of circulating immune cells in 244 CLL patients and 52 healthy controls was performed using flow cytometry and analysed by multivariate Patient Similarity Networks (PSNs). Our study revealed high inter-individual heterogeneity in the distribution and activation of bystander immune cells in CLL, depending on the bulk of the CLL cells. High CLL counts were associated with low activation on circulating monocytes and T cells and vice versa. The highest activation of immune cells, particularly of intermediate and non-classical monocytes, was evident in patients treated with novel agents. PSNs revealed a low activation of immune cells in CLL progression, irrespective of IgHV status, Binet stage and TP53 disruption. Patients with high intermediate monocytes (> 5.4%) with low activation were 2.5 times more likely (95% confidence interval 1.421–4.403, P = 0.002) to had shorter time-to-treatment than those with low monocyte counts. Our study demonstrated the association between the activation of circulating immune cells and the bulk of CLL cells. The highest activation of bystander immune cells was detected in patients with slow disease course and in those treated with novel agents. The subset of intermediate monocytes showed predictive value for time-to-treatment in CLL.

Monocyte/Macrophage-Mediated Innate Immunity in HIV-1 Infection: From Early Response to Late Dysregulation and Links to Cardiovascular Diseases Onset

Although monocytes and macrophages are key mediators of the innate immune system, the focus has largely been on the role of the adaptive immune system in the context of human immunodeficiency virus (HIV) infection. Thus more attention and research work regarding the innate immune system-especially the role of monocytes and macrophages during early HIV-1 infection-is required. Blood monocytes and tissue macrophages are both susceptible targets of HIV-1 infection, and the early host response can determine whether the nature of the infection becomes pathogenic or not. For example, monocytes and macrophages can contribute to the HIV reservoir and viral persistence, and influence the initiation/extension of immune activation and chronic inflammation. Here the expansion of monocyte subsets (classical, intermediate and non-classical) provide an increased understanding of the crucial role they play in terms of chronic inflammation and also by increasing the risk of coagulation during HIV-1 infection. This review discusses the role of monocytes and macrophages during HIV-1 pathogenesis, starting from the early response to late dysregulation that occurs as a result of persistent immune activation and chronic inflammation. Such changes are also linked to downstream targets such as increased coagulation and the onset of cardiovascular diseases.

Mechanistic consideration of the effect of perioperative volatile anesthetics on phagocytes

A growing literature has shown that volatile anesthetics are promiscuous molecules targeting multiple molecules, some of which are critical for immunological functions. We focused on studies that delineated target molecules of volatile anesthetics on immune cells and summarized the effects of volatile anesthetics on immune functions. We also presented the perspectives of studying volatile anesthetics-mediated immunomodulation.

Migrating Lung Monocytes Internalize and Inhibit Growth of Aspergillus fumigatus Conidia

Monocytes are important players to combat the ubiquitously present fungus Aspergillus fumigatus. Recruitment of monocytes to sites of fungal A. fumigatus infection has been shown in vivo. Upon exposure to A. fumigatus in vitro, purified murine and human blood monocytes secrete inflammatory cytokines and fungicidal mediators. Mononuclear tissue phagocytes are phenotypically and functionally different from those circulating in the blood and their role in antifungal defenses is much less understood. In this study, we identified a population of migrating CD43⁺ monocytes in cells isolated from rat distal lungs. These cells are phenotypically different from alveolar macrophages and show distinct locomotory behavior on the surface of primary alveolar cells resembling previously described endothelial patrolling monocytes. Upon challenge, the CD43⁺ monocytes internalized A. fumigatus conidia resulting in inhibition of their germination and hyphal growth. Thus, migrating lung monocytes might play an important role in local defense against pulmonary pathogens.

Hypotheses about sub-optimal hydration in the weeks before coronavirus disease (COVID-19) as a risk factor for dying from COVID-19

To address urgent need for strategies to limit mortality from coronavirus disease 2019 (COVID-19), this review describes experimental, clinical and epidemiological evidence that suggests that chronic sub-optimal hydration in the weeks before infection might increase risk of COVID-19 mortality in multiple ways. Sub-optimal hydration is associated with key risk factors for COVID-19 mortality, including older age, male sex, race-ethnicity and chronic disease. Chronic hypertonicity, total body water deficit and/or hypovolemia cause multiple intracellular and/or physiologic adaptations that preferentially retain body water and favor positive total body water balance when challenged by infection. Via effects on serum/glucocorticoid-regulated kinase 1 (SGK1) signaling, aldosterone, tumor necrosis factor-alpha (TNF-alpha), vascular endothelial growth factor (VEGF), aquaporin 5 (AQP5) and/or Na⁺/K⁺-ATPase, chronic sub-optimal hydration in the weeks before exposure to COVID-19 may conceivably result in: greater abundance of angiotensin converting enzyme 2 (ACE2) receptors in the lung, which increases likelihood of COVID-19 infection, lung epithelial cells which are pre-set for exaggerated immune response, increased capacity for capillary leakage of fluid into the airway space, and/or reduced capacity for both passive and active transport of fluid out of the airways. The hypothesized hydration effects suggest hypotheses regarding strategies for COVID-19 risk reduction, such as public health recommendations to increase intake of drinking water, hydration screening alongside COVID-19 testing, and treatment tailored to the pre-infection hydration condition. Hydration may link risk factors and pathways in a unified mechanism for COVID-19 mortality. Attention to hydration holds potential to reduce COVID-19 mortality and disparities via at least 5 pathways simultaneously.

Up-Regulation of CD163 Expression in Subpopulations of Blood Monocytes After Kidney Allograft Transplantation

M2 macrophages expressing CD163 are known to suppress immune responses but have been also found in biopsies of patients with chronic kidney allograft injury associated with interstitial fibrosis. The aim of our study was to evaluate the expression of CD163 in blood monocytes, precursors of tissue macrophages, in kidney allograft recipients with uncomplicated outcome (n=94) compared with those developing acute rejection (n=44). Blood samples were collected before the transplantation and at 1 week, 1 month and 1 year. The expression of CD163 increased during the first week after the transplantation not only in classical (CD14+CD16-) but also in intermediate (CD14+CD16+) and nonclassical (CD14lowCD16+) monocytes in all patients regardless of their rejection status. In patients developing acute rejection, higher pre-transplant expression of CD163 on blood monocytes was found. In vitro experiments confirmed strong induction of membrane CD163 on monocytes together with CD206 (an alternative marker of M2 macrophages) in response to IL-10. We assume from our data that dramatic upregulation of CD163 by peripheral blood monocytes may have a pathophysiological role in early phases after kidney allograft transplantation and high pre-transplant expression of CD163 on blood monocytes might be involved in events leading to acute rejection.

Increased proportion and altered properties of intermediate monocytes in the peripheral blood of patients with lower risk Myelodysplastic Syndrome

Immune deregulation has a critical role in the pathogenesis of lower risk myelodysplastic syndromes (MDS). The cells of the macrophage/monocyte lineage have been reported to contribute to the inflammatory process in MDS through impaired phagocytosis of the apoptotic hemopoietic cells and abnormal production of cytokines. In the present study we assessed the number of peripheral blood (PB) monocyte subsets, namely the classical CD14^bright/CD16^-, intermediate CD14^bright/CD16⁺ and non-classical CD14^dim/CD16⁺ cells, in patients with lower risk (low/intermediate-I) MDS (n = 32). We also assessed the production of tumor necrosis factor (TNF)α by patient PB monocytes in response to immune stimulus as well as their transcriptome profile. Compared to age- and sex-matched healthy individuals (n = 19), MDS patients had significantly lower number of classical and increased number of intermediate monocytes. Patient intermediate monocytes displayed increased production of TNFα following stimulation with lipopolysaccharide, compared to healthy individuals. Transcriptional profiling comparison of CD16⁺ monocytes from patients and controls revealed 43 differentially expressed genes mostly associated with biological pathways/processes relevant to hemopoiesis, immune signaling and cell adhesion. These data provide evidence for the first-time that distinct monocyte subsets display abnormal quantitative and functional characteristics in lower risk MDS substantiating their role in the immune deregulation associated with the disease.

Low-density granulocytes and monocytes as biomarkers of cardiovascular risk in systemic lupus erythematosus

OBJECTIVE

The aim was to evaluate the most relevant cell populations involved in vascular homeostasis as potential biomarkers of SLE-related cardiovascular disease (CVD).

METHODS

Low-density granulocytes (LDGs), monocyte subsets, endothelial progenitor cells, angiogenic T (Tang) cells, CD4+CD28null and Th1/Th17 lymphocytes and serum cytokine levels were quantified in 109 SLE patients and 33 controls in relationship to the presence of subclinical carotid atheromatosis or cardiovascular disease. A second cohort including 31 recent-onset SLE patients was also included.

RESULTS

Raised monocyte and LDG counts, particularly those LDGs negative for CD16/CD14 expression (nLDGs), in addition to the ratios of monocytes and nLDGs to high-density lipoprotein-cholesterol (HDLc) molecules (MHR and nLHR, respectively), were present in SLE patients with traditional risk factors or subclinical atheromatosis but not in those who were CV-free, thus revealing their value in the identification of patients at risk of CVD, even at the onset of disease. Accordingly, nLDGs were correlated positively with carotid intima-media thickness (cIMT) and with inflammatory markers (CRP and IL-6). A bias towards more differentiated monocyte subsets, related to increased IFN-α and IL-17 serum levels, was also observed in patients. Intermediate monocytes were especially expanded, but independently of their involvement in CVD. Finally, CD4+CD28null, Th17 and Th1 lymphocytes were increased, with CD4+CD28null and Th17 cells being associated with cIMT, whereas endothelial progenitor and Tang cell levels were reduced in all SLE patients.

CONCLUSION

The present study highlights the potential use of MHR and nLHR as valuable biomarkers of CVD risk in SLE patients, even at diagnosis. The increased amounts of nLDGs, monocytes, Th17 and senescent-CD28null subsets, coupled with reduced pro-angiogenic endothelial progenitor cells and Tang cells, could underlie the development of atheromatosis in SLE.

Leukocyte populations in peripheral blood of dromedary camels with clinical endometritis

Endometritis represents the main cause of reproductive failure in dromedary camels. In dromedary camels, associations between endometritis-causing pathogen-species, disease severity, and systemic changes in the immune system have not been evaluated. In the current study, there was use of flow cytometry and immunofluorescence of membrane proteins for the evaluation of leukocyte subsets and the cellular phenotype in blood of camels with clinical endometritis and evaluations of associations with disease severity and endometritis-causing pathogens. Animals with endometritis had markedly larger numbers of total leukocytes and neutrophils. Although total lymphocyte and monocyte counts did not differ between camels with and without clinical endometritis, there were lesser numbers of total and effector CD4-positive T cells in camels with endometritis. Among monocytes, number of camel inflammatory monocytes (Mo-II) was markedly greater, whereas Mo-III numbers were less in the blood of camels with clinical endometritis. Number of inflammatory monocytes was also indicative of endometritis severity grade. Among camels with clinical endometritis, E. coli- and S. aureus-infected animals had similar endometritis grades and comparable phenotype and composition patterns of leukocytes. Neutrophils and monocytes of camels with clinical endometritis had fewer cell adhesion molecules (i.e., CD11a and CD18). Collectively, the results from the current study allowed for identification of associations between endometritis severity grade and larger numbers of inflammatory monocytes. The results also indicate there is no association between endometritis pathogen-species and changes in phenotype or composition of blood leukocytes.

Blood Monocyte Subsets with Activation Markers in Relation with Macrophages in Non-Small Cell Lung Cancer

Simple Summary

This study characterized monocyte subtypes: classical, intermediate, and non-classical with the expression of surfaces markers: CD62L, CD11c, CD18, HLA-DR in non-small cell lung cancer patients (NSCLC) compared to healthy controls and correlations between monocyte subtypes and macrophages in the lung cancer microenvironment. We confirmed the presence of various monocyte subtypes in the blood with predominance of classic monocytes and a higher proportion of classical and intermediate monocytes in NSCLC patients than in healthy subjects. Our observation that intermediate monocytes with CD11c+ and HLA-DR+ expression correlation with the amount of macrophages from the lung cancer microenvironment may indicate role of these cells in cancer immunity. A high proportion of monocytes with low expression of CD62L indicates participation of monocytes in attenuation of anticancer response. The detection and monitoring of the presented monocyte subsets in the blood might be a useful test in lung cancer.

Abstract

(1) The cells from the monocyte line play an important role as regulators of cancer development and progression. Monocytes present pro- and anti-tumor immunity and differentiation into macrophages. Macrophages are predominant in the lung cancer environment and could be evaluated by bronchoalveolar lavage fluid (BALF). (2) The aim of the study was analysis of monocytes: classical, intermediate and non-classical with expression of: CD62L, CD11c, CD18, HLA-DR in non-small cell lung cancer (NSCLC) and their correlation with BALF macrophages from lungs with cancer (clBALF) and healthy lungs (hlBALF). (3) A total of 24 patients with NSCLC and 20 healthy donors were investigated. Monocyte subtyping and macrophage counts were performed by flow cytometry. (4) There are three types in peripheral blood (PB): classical monocytes (CD14++CD16-), intermediate (CD14+CD16+) and non-classical (CD14-/+CD16++). We noticed a higher proportion of classical and intermediate monocytes in lung cancer than in healthy donors (76.2 vs. 67.3, and 7.9 vs. 5.2 p < 0.05). We observed a higher proportion of macrophages in clBALF then in hlBALF. A higher CD62L expression on all monocyte subtypes in healthy donors than in study group was found. There were positive correlations between: classical CD11c+, intermediate CD11c+, intermediate HLA-DR+ monocytes in PB with macrophages in clBALF. We did not observe these correlations with macrophages from hlBALF. (5) A predominance of classical and intermediate monocytes in lung cancer and the correlation between intermediate monocytes with CD11c+ and HLA-DR+ and macrophages from the NSCLC milieu support a role of monocyte-line cells in cancer immunity. A high proportion of monocytes with low expression of CD62L indicates the participation of monocytes in attenuation of anticancer response.