Peripheral Blood Monocyte Subpopulations Research Articles

M1/M2 macrophages: origin, phenotype, methods of production, interaction with natural killer cells and trophoblast

This review presents current data on the origin of monocytes/macrophages, the conditions necessary for the differentiation of monocytes into M1 or M2 macrophages. Three subpopulations of peripheral blood monocytes are described: (I) classical – the main subpopulation (85-90%), effectively carrying out phagocytosis; (II) intermediate monocytes (5-10%) – participate in antigen processing and presentation, in angiogenesis, vascular endothelium restoration; (III) non-classical monocytes (10%) - "patrol" vascular network, remove cellular debris, participate in tissue remodeling. The review provides detailed characteristics for each subclass of macrophages: pro-inflammatory (M1) and anti-inflammatory (M2), which play different roles in the initiation and resolution of inflammation; their phenotype, the spectrum of secreted cytokines, the expression of transcription factors, and the functions performed are described. For the M2 population, the features of the subpopulation are described in detail: M2a, M2b, M2c, M2d. The review presents methods and approaches to obtaining polarized macrophages in vitro from both peripheral blood monocytes and cells of transplanted cultures based on signals received by macrophages in vivo; the phenotype, cytokine production and functional properties of artificially polarized macrophages depending on the conditions of their production are given. The review examines in detail the features of contact and distant interaction of macrophages of various subclasses with microenvironment cells on the example of natural killer cells and trophoblast cells, provides information on changes in the phenotype, transcriptional and secretory profile of interacting cells. The mechanisms of trophoblast control of macrophage differentiation into a unique M2 population of decidual macrophages controlling both the development and functioning of the trophoblast and its apoptosis are described. The review examines in detail the currently known variants of the interaction of macrophage subpopulations with natural killers. The influence of Mf on NK cells manifests itself in a change in the expression of transcription factors by the latter, which determine not only their differentiation, but also their functional activity. Macrophages are considered as cells that actively influence the functional state and differentiation of natural killers. The review examines the mechanisms of the relationship of all three types of cells: macrophages, trophoblast and natural killers in the area of uteroplacental contact. The study of the interactions of these cells will shed light not only on the features of intercellular relationships in the area of uteroplacental contact, but also on the relationship of tumor cells with NK cells and macrophages.

Prediction of outcome using CD14++CD16-, CD14++CD16+ and CD14+CD16++ monocyte subpopulations in patients with complicated intra-abdominal infections.

There is still no study investigating the prognostic performance of CD14++CD16-, CD14++CD16+ and CD14+CD16++ monocyte subpopulations in complicated intra-abdominal infections (cIAIs); therefore, we aimed to evaluate the association between monocyte subtypes and outcome in such patients. A single-center prospective study was conducted at a University Hospital Stara Zagora between November 2018 and August 2021. Preoperatively and on the 3rd postoperative day (POD), we measured the levels of CD14++CD16-, CD14++CD16+ and CD14+CD16++ monocytes in peripheral blood using flow cytometry in 62 patients with cIAIs and 31 healthy controls. Nine of the 62 patients died during hospitalization. Survivors had higher pre-surgery percentages of CD14++CD16- classical monocytes and higher percentage of these cells predicted favorable outcome in ROC analysis (AUROC = 0.781, p = 0.008). The CD14++CD16+ intermediate monocyte percentages were higher in non-survivors both pre- and postoperatively but only the higher preoperative values predicted a lethal outcome (AUROC = 0.722, p = 0.035). For CD14+CD16++ non-classical monocytes, non-survivors had lower percentages on day 3 post-surgery and low percentage was predictive of lethal outcome (AUROC = 0.752, p = 0.046). Perioperative levels of monocyte subpopulations in peripheral blood show a great potential for prognostication of outcome in patients with cIAIs.

GLOBAL CHARACTERIZATION OF MONOCYTE REVEALS A STRESS SIGNATURE INDUCED BY MULTIPLE MYELOMA THROUGH SINGLE‐CELL RNA SEQUENCING

Background: A growing body of evidence has indicated impaired function or compositional changes of monocytes in inflammatory disorders, such as acute respiratory syndrome and covid-19. In myeloma tumor microenvironment, activation of type I interferon pathway and dysregulated expression of major histocompatibility complex type II genes are observed in classical monocytes, which result in loss of antigen presentation of monocytes. The proportions of BAFF+PD-L1+ monocytes in the bone marrow also correlate with survival of myeloma patients following chimeric antigen-receptor T cell therapy. Nevertheless, the mechanisms underlying PB and BM monocytes defects in myeloma remain poorly addressed, at least in part by the lack of large scale scRNA-seq studies. To resolve the heterogeneous bone marrow and peripheral blood monocyte subpopulations and their transcriptional factors between healthy donors and multiple myeloma patients. Methods: We conducted scRNA-seq on monocytes of 7 newly diagnosed myeloma patients and 12 healthy donors. Specifically, 3 and 5 bone marrow aspirates and 9 and 7 peripheral blood samples of 12 healthy controls and 7 newly diagnosed patients were obtained, respectively. Results: Heterogeneous bone marrow and peripheral blood monocyte subpopulations and their transcriptional factors were resolved. The function characteristics of monocyte were compared between MM patients and healthy donors, which indicated a stress signature induced by multiple myeloma. Furthermore, we identified two monocyte differentiation pathways, and discovered that bone marrow monocyte feature type I IFN-associated differentiation dysregulation in patients with MM as well as dysregulated patterns at transcriptome. Finally, we included 10 MM patients as a validation cohort, by tracking the stress signature over time in those patients undergoing first-line treatment, we founded that the stress signature was partially overcome by antitumor therapy. Conclusion: Our results provided further insight into transcriptional and differentiation changes occurring in the bone marrow and peripheral blood monocytes from patients with multiple myeloma and hint and mechanisms of immune evasion. Encore Abstract - previously submitted to EHA 2023 The research was funded by: This investigation was supported by the International Cooperation Projects of National Natural Science Foundation (grants 81920108006), CAMS Innovation Fund for Medical Sciences (CIFMS) (grants 2022-I2M-1-022), the National Natural Science Foundation (grants 81630007; grants 82270218, 81670202; grants 81900214), and the Atlas of Blood Cell Alliance. Keywords: genomics, epigenomics, and other -omics, microenvironment, multiple myeloma No conflicts of interests pertinent to the abstract.

Cytokine expression by CD163+ monocytes in healthy and Actinobacillus pleuropneumoniae-infected pigs

Distinct monocyte subpopulations have been previously described in healthy pigs and pigs experimentally infected with Actinobacillus pleuropneumoniae (APP). The CD163+ subpopulation of bone marrow (BM), peripheral blood (PB) and lung monocytes was found to play an important role in the inflammatory process. The inflammation is accompanied by elevation of inflammatory cytokines. The aim of the study was to evaluate the contribution of CD163+ monocytes and macrophages to cytokine production during APP-induced lung inflammation.Cytokine production was assessed by flow cytometry (FC) and quantitative PCR (qPCR) in CD163+ monocytes and by qPCR, immunohistochemistry/fluorescence in lungs and tracheobronchial lymph nodes (TBLN). Despite the systemic inflammatory response after APP infection, BM and PB CD163+ monocytes did not express elevated levels of a wide range of cytokines compared to control pigs. In contrast, significant amounts of IL-1β, IL-6, IL-8 and TNF-α were produced in lung lesions and IL-1β in the TBLN. At the protein level, TNF-α was expressed by both CD163+ monocytes and macrophages in lung lesions, whereas IL-1β, IL-6 and IL-8 expression was found only in CD163+ monocytes; no CD163+ macrophages were found to produce these cytokines. Furthermore, the quantification of CD163+ monocytes expressing the two cytokines IL-1β and IL-8 that were most elevated was performed. In lung lesions, 36.5% IL-1β positive CD163+ monocytes but only 18.3% IL-8 positive CD163+ monocytes were found.In conclusion, PB and BM CD163+ monocytes do not appear to contribute to the elevated cytokine levels in plasma. On the other hand, CD163+ monocytes contribute to inflammatory cytokine expression, especially IL-1β at the site of inflammation during the inflammatory process.

Philadelphia-negative myeloproliferative neoplasms display alterations in monocyte subpopulations frequency and immunophenotype.

Philadelphia-negative myeloproliferative neoplasms (MPN) are clonal hematological diseases associated with driver mutations in JAK2, CALR, and MPL genes. Moreover, several evidence suggests that chronic inflammation and alterations in stromal and immune cells may contribute to MPN’s pathophysiology. We evaluated the frequency and the immunophenotype of peripheral blood monocyte subpopulations in patients with polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (MF). Peripheral blood monocytes from PV (n = 16), ET (n = 16), and MF (n = 15) patients and healthy donors (n = 10) were isolated and submitted to immunophenotyping to determine the frequency of monocyte subpopulations and surface markers expression density. Plasma samples were used to measure the levels of soluble CD163, a biomarker of monocyte activity. PV, ET, and MF patients presented increased frequency of intermediate and non-classical monocytes and reduced frequency of classical monocytes compared to controls. Positivity for JAK2 mutation was significantly associated with the percentage of intermediate monocytes. PV, ET, and MF patients presented high-activated monocytes, evidenced by higher HLA-DR expression and increased soluble CD163 levels. The three MPN categories presented increased frequency of CD56+ aberrant monocytes, and PV and ET patients presented reduced frequency of CD80/86+ monocytes. Therefore, alterations in monocyte subpopulations frequency and surface markers expression pattern may contribute to oncoinflammation and may be associated with the pathophysiology of MPN.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12032-022-01825-6.

Red Blood Cell Released ATP Regulates Systemic Immune Response in Atherosclerosis

Our studies demonstrated that disturbed flow-induced ATP release from red blood cells (RBCs) via pannexin 1 (Panx1) channels plays a significant role in site-specific vascular inflammation and atherosclerosis. This is supported by a 40-60% reduction of atherosclerotic plaque observed in high fat diet (HFD)-fed ApoE-/- mice with RBC panx1 deletion that nearly abolished the release of ATP. Given the interplay of the immune system in atherosclerosis, we hypothesize that disturbed blood flow-induced release of ATP from RBCs at micromolar concentration is a major source of extracellular ATP (orders of magnitude higher than other ATP sources), which plays a crucial role in purinergic signaling-mediated local and systemic immune cell activation, cytokine production, and phenotypic transformation, serving as an important mediator in immune system-mediated initiation and progression of atherosclerosis. To test this hypothesis, we conducted experiments in 3 mouse groups (n = 4 to 12 per group): chow diet-fed wild type control, and 16 weeks HFD-fed ApoE-/- and ApoE-/-/RBC Panx1-/- mice. Plasma inflammatory cytokines were measured via ELISA. Subpopulations of peripheral blood monocytes (PBMCs) were characterized by flow cytometry, and the cytokine secretion capacity of T cells was examined by intracellular interferon-gamma (IFN-γ) staining in isolated splenocytes. Results showed that plasma IFN-γ and interleukin 1 beta (IL-1β) increased 10 and 8 fold, respectively, in HFD ApoE-/- mice when compared to the control group. These increases were reduced to levels close to the control in HFD ApoE-/-/RBC Panx1-/- mice. PBMCs analysis showed a significantly increased pro-inflammatory Ly6Chigh monocytes in HFD ApoE-/- mice from 2.9 ± 0.5% (control) to 19.2 ± 2.0%, while only 7.6 ± 1.0% was found in HFD ApoE-/-/RBC Panx1-/- mice. Intracellular IFN-γ staining of isolated splenocytes from HFD ApoE-/- mice showed a 5-fold increase in IFN-γ+ T cells (%) when compared to the control. In contrast, ApoE-/-/RBC Panx1-/- mice had significantly reduced percentage of IFN-γ+ T cells when compared with ApoE-/- mice (0.12 ± 0.03% vs 1.5 ± 0.48%, p < 0.05), especially in CD4+ T cells (0.06 ± 0.01% vs 0.79 ± 0.21%, p < 0.05). These cells further demonstrated their increased inflammatory potential, as stimulation with phorbol 12-myristate 13-acetate and Ionomycin yielded a markedly higher percentage of IFN-γ+ T cells in the HFD ApoE-/- group (40.4 ± 3.3%) than control (22.7 ± 1.8%) and ApoE-/-/RBC Panx1-/- group (26.6 ± 3.2%), and more prominent differences were found in CD4+ subgroup with values at 29.0 ± 2.5%, 11.1 ± 1.7%, and 14.5 ± 2.9%, respectively (p<0.05). In conclusion, our results indicate that shear stress-induced release of ATP from RBCs via Panx1 channels plays important roles in the immune cell recruitment, activation, and cytokine production, contributing to immune system-mediated vascular inflammation and the initiation and progression of atherosclerosis. Our findings provide novel mechanistic insight into local hemodynamics and systemic risk factor-mediated vascular pathogenesis and disease progression, directly benefiting clinical diagnosis and the prediction of atherosclerosis development.

Cellular markers of chronic obstructive pulmonary disease from exposure to nanoparticlecontaining aerosols

Introduction. The role of industrial aerosol nanoparticles in the development of chronic obstructive pulmonary disease is still poorly understood. The aim of study is to determine the distribution of monocyte subpopulations in patients with chronic obstructive pulmonary disease under the influence of industrial aerosols containing nanoparticles. Materials and methods. A single-center cohort observational study included patients with chronic obstructive pulmonary disease (COPD) (GOLD 2011 criteria) who were exposed to industrial aerosols (n=32), COPD patients, tobacco smokers (n=35), and conditionally healthy individuals without occupational hazards (n=29). Nanoparticles in the air of the working area were determined by inductively coupled plasma atomic emission spectrometry and scanning electron microscopy. Metal-containing nanoparticles (Pb, Fe, Cr) predominated in the casters' workplaces, while the grinders were mainly exposed to silicon dioxide nanoparticles. The groups were comparable by gender, age, and duration of COPD. Monocyte subpopulations in peripheral blood were determined by flow cytofluorometry. Results. In COPD patients who worked in contact with an industrial aerosol containing metal nanoparticles, the proportion of "classical" CD14+CD16- monocytes was increased, and the proportion of "intermediate" CD14+CD16+ and "non-classical" CD14dimCD16+ was reduced. The percentage of "non-classical" monocytes exposed to silicon dioxide nanoparticles was increased, and the percentage of "intermediate" monocytes was reduced. At the same time, the proportion of classical monocytes was highest in patients with COPD who worked under the influence of metal nanoparticles (84.3%±6.3%), intermediate monocytes - in patients with COPD due to tobacco smoking (6.1%±1.5%), non-classical monocytes - in the group of COPD and contact with silicon dioxide nanoparticles (20.45%±0.25%). Conclusions. COPD under the influence of industrial aerosol containing metal nanoparticles is characterized by an increase in the proportion of "classical' monocytes, and silicon dioxide nanoparticles - "non-classical”. The level of subpopulations of blood monocytes is a promising marker of professionally caused COPD.

The dysregulation of monocyte subpopulations in individuals at risk of developing rheumatoid arthritis.

Individuals carrying antibodies against citrullinated proteins (ACPA) are at high risk of developing RA. EULAR provided a clinical definition of individuals with arthralgia suspicious for progression to RA (clinically suspect arthralgia, CSA). The alteration of monocyte subpopulations in patients with established RA has been previously described. We analysed peripheral blood monocyte subpopulations in individuals with arthralgia at risk of RA. We included 70 at-risk individuals, defined as having arthralgia without arthritis and being either ACPA+ or meeting the clinical CSA definition, 23 patients with early RA (ERA) and 19 healthy controls (HCs). Monocytes classified as classical (CD14++CD16-), intermediate (CD14++CD16+/++) and nonclassical (CD14-/+CD16++) were analysed by flow cytometry. Of the 70 at-risk individuals, 46 were ACPA+ and 45 met the CSA definition. The at-risk individuals and, especially, ERA patients had a lower percentage of classical monocytes and a higher percentage of nonclassical monocytes than the HCs. ACPA positivity had no effect on the difference in the distribution of the monocyte subsets between at-risk individuals and ERA patients, but a difference was determined in those reaching the ERA phase. However, when compared with HCs, the shift of monocyte subsets was more significant in ACPA+ than in ACPA- individuals with arthralgia. This trend was observed in individuals who did not meet the CSA definition. This finding was, however, determined by a selection bias, as these individuals were solely ACPA+. The shift from classical to nonclassical monocyte subpopulations was observed already in individuals at risk of developing RA.

High CD163 Expression on Classical Monocytes Is Associated with Immune Control of HBV Infection in Noncirrhotic Patients

Background and Aims. The functional impairment of monocytes may contribute to the persistence of HBV infection. This study aims to assess monocyte subpopulations, monocyte expression of CD163, plasma sCD163, and sTWEAK in patients with chronic HBeAg-negative HBV infection at different phases of disease. Methods. Fifty-nine patients with CHB, 9 with a history of HBsAg/anti-HBs seroconversion, were enrolled. The control group consisted of 15 healthy volunteers. Subpopulations of peripheral blood monocytes were distinguished by CD14 and CD16. Membrane expression of CD163 was assessed by flow cytometry, plasma sCD163 concentration by ELISA, and sTWEAK by bead-based multiplexed immunoassay system. Results. CD163 expression was increased in classical and intermediate monocytes in CHB patients and those with HBsAg/anti-HBs seroconversion. CD163 expression on classical monocytes was associated with status of immune control and thus significant in HBV infection as compared to active hepatitis. Plasma sCD163 concentration was increased in CHB patients and those with HBsAg/anti-HBs seroconversion vs. the control group. Positive correlations between plasma sCD163 and ALT, as well as APRI, were observed. Plasma sTWEAK concentration was lower in CHB patients in comparison to patients with HBsAg/anti-HBs seroconversion. Conclusions. Exposure to HBV antigens alters monocyte subsets’ frequencies and activation. The expression of CD163 on classical monocytes increased in parallel with improved immune control of the HBV infection. Patients who seroconverted HBsAg had the highest expression of CD163 on monocytes, which suggests involvement of monocytes in immune control of HBV infection. Persistent inflammation is accompanied by higher CD163 expression and sCD163 level and lower sTWEAK level.

TNF-α Inhibitors Decrease Classical CD14hiCD16- Monocyte Subsets in Highly Active, Conventional Treatment Refractory Rheumatoid Arthritis and Ankylosing Spondylitis.

Monocytes are pivotal cells in inflammatory joint diseases. We aimed to determine the effect of TNF-α inhibitors (TNFi) on peripheral blood monocyte subpopulations and their activation in ankylosing spondylitis (AS) and rheumatoid arthritis (RA) patients with high disease activity. To address this, we studied 50 (32 AS, 18 RA) patients with highly active disease with no prior history of TNFi use who were recruited and assigned to TNFi or placebo treatment for 12 weeks. Cytometric and clinical assessment was determined at baseline, four, and 12 weeks after initiation of TNFi treatment. We observed that treatment with TNFi led to a significant decrease in CD14hiCD16− monocytes in comparison to placebo, while circulating CD14dimCD16+ monocytes significantly increased. The TNFi-induced monocyte subset shifts were similar in RA and AS patients. While the percentage of CD14dimCD16+ monocytes increased, expression of CD11b and CD11c integrins on their surface was significantly reduced by TNFi. Additionally, CD45RA+ cells were more frequent. The shift towards nonclassical CD14dimCD16+ monocytes in peripheral blood due to TNFi treatment was seen in both AS and RA. This may reflect reduced recruitment of these cells to sites of inflammation due to lower inflammatory burden, which is associated with decreased disease activity.

Residual Renal Function in Hemodialysis and Inflammation.

Residual renal function (RRF) has an important effect on uremic toxin clearance, on volume control, on quality of life, and on mortality. In patients with chronic kidney disease (CKD), microinflammation with an increased percentage of CD14+ /CD16++ inflammatory monocytes has been reported, even with no clinical evidence of inflammation. No correlation has been established between these and RRF in hemodialysis (HD) patients. Our objective was to assess the relationship between RRF and the inflammatory parameters in HD patients. Cross-sectional observational study was carried out on 69 adult patients on chronic HD for at least 6 months, from which demographic, analytic and HD-technique data were collected and the following were measured: (i) RRF with average urea and creatinine clearance ((CCr + CU)/2) in 24-h urine (if >1 mL/min and diuresis >100 mL/day, RRF was considered); (ii) Inflammation through biochemical parameters (C-reactive protein, β2 microglobulin, albumin) and monocyte subpopulations in peripheral blood. The average age was 70.9 [40-88] years old; 38 (55.1%) were male; and 25 (36.2%) were diabetic. 43.5% (30/69) presented RRF, with an average of ((CCr + CU)/2): 1.8 (2.6) mL/min and diuresis: 454.5 (569) mL /24 h. Patients with RRF presented lower concentrations of C-reactive protein (6.2 vs 21.4 mg/L) (P = 0.038) and a lower percentage of non-classical CD14+ /CD16++ monocytes (14.6 vs. 28.3%, P = 0.02). In our study, patients with RRF present lower concentrations of inflammatory parameters, which is another reason why its preservation is an essential objective in HD.

Abstract 3180: Chemotherapeutical agent triggers transient resistance of cancer cells by promoting ABCB1 intercellular transfer

Abstract Multidrug resistance remains a major impediment to successful chemotherapy. In clinical chemotherapy, some patients often develop chemoresistance quite rapidly, the underlying mechanism remains elusive. Herein, we report that a transient exposure to chemotherapeutic agents can acutely promote the intercellular transfer of ABCB1 through stimulating Rab8B-mediated secretion of microvesicles (MVs) containing ABCB1 in drug-resistant donor cells, and promoting parallelly the endocytic recycling of ABCB1 in recipient tumor cells via the downregulation of Rab5. Sensitive recipient cells take up these ABCB1-incorporated MVs by a clathrin- and dynamin 2- dependent endocytic pathway, thereby acquiring a transient resistance to chemotherapeutic agents which are ABCB1 substrates. More fascinatingly, ABCB1 molecules can locally or distantly transfer to recipient tumor cells and respond to chemotherapeutical drug in the xenograft tumor models. In some cases of patients with NSCLC, a variable increase of ABCB1 surface expression was also detected in the peripheral blood monocyte subpopulations after they received the first chemotherapy. Our findings proposed a novel molecular mechanism of how sensitive cancer cells rapidly acquire the emergency resistance to chemotherapeutic agents by stimulating intercellular transfer of ABCB1. The precise modulation of this process may provide a valid therapeutic strategy to alleviate the MDR phenotype for successful treatment. Citation Format: Xiaokun Wang, Dongjuan Qiao, Likun Chen, Liyan Huang, Meng Xu, Zhen Chen, Fang Wang, Zhesheng Chen, Musheng Zeng, Li-Wu Fu. Chemotherapeutical agent triggers transient resistance of cancer cells by promoting ABCB1 intercellular transfer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3180. doi:10.1158/1538-7445.AM2017-3180

Pivotal Role for CD16+ Monocytes in Immune Surveillance of the Central Nervous System.

Monocytes represent a heterogeneous population of primary immune effector cells. At least three different subsets can be distinguished based on expression of the low-affinity FcγRIII: CD14(++)CD16 -: classical monocytes, CD14(++)CD16(+) intermediate monocytes, and CD14(+)CD16 ++: non-classical monocytes. Whereas CD16 -: classical monocytes are considered key players in multiple sclerosis (MS), little is known on CD16(+) monocytes and how they contribute to the disease. In this study, we examined the frequency and phenotype of monocyte subpopulations in peripheral blood, cerebrospinal fluid (CSF), and brain biopsy material derived from MS patients and controls. Furthermore, we addressed a possible monocyte dysfunction in MS and analyzed migratory properties of monocyte subsets using human brain microvascular endothelial cells. Our ex vivo studies demonstrated that CD16(+) monocyte subpopulations are functional but numerically reduced in the peripheral blood of MS patients. CD16(+) monocytes with an intermediate-like phenotype were found to be enriched in CSF and dominated the CSF monocyte population under noninflammatory conditions. In contrast, an inversed CD16(+) to CD16 -: CSF monocyte ratio was observed in MS patients with relapsing-remitting disease. Newly infiltrating, hematogenous CD16(+) monocytes were detected in a perivascular location within active MS lesions, and CD16(+) monocytes facilitated CD4(+) T cell trafficking in a blood -: brain barrier model. Our findings support an important role of CD16(+) monocytes in the steady-state immune surveillance of the CNS and suggest that CD16(+) monocytes shift to sites of inflammation and contribute to the breakdown of the blood-brain barrier in CNS autoimmune diseases.

Regulation of peripheral classical and non-classical monocytes on infliximab treatment in patients with rheumatoid arthritis and ankylosing spondylitis

ObjectiveTo investigate the regulatory effect of tumour necrosis factor (TNF) blockade with infliximab on the distribution of peripheral blood monocyte subpopulations in patients with rheumatoid arthritis (RA) and ankylosing spondylitis...

Dopamine increases CD14+CD16+ monocyte migration and adhesion in the context of substance abuse and HIV neuropathogenesis.

Drug abuse is a major comorbidity of HIV infection and cognitive disorders are often more severe in the drug abusing HIV infected population. CD14+CD16+ monocytes, a mature subpopulation of peripheral blood monocytes, are key mediators of HIV neuropathogenesis. Infected CD14+CD16+ monocyte transmigration across the blood brain barrier mediates HIV entry into the brain and establishes a viral reservoir within the CNS. Despite successful antiretroviral therapy, continued influx of CD14+CD16+ monocytes, both infected and uninfected, contributes to chronic neuroinflammation and the development of HIV associated neurocognitive disorders (HAND). Drug abuse increases extracellular dopamine in the CNS. Once in the brain, CD14+CD16+ monocytes can be exposed to extracellular dopamine due to drug abuse. The direct effects of dopamine on CD14+CD16+ monocytes and their contribution to HIV neuropathogenesis are not known. In this study, we showed that CD14+CD16+ monocytes express mRNA for all five dopamine receptors by qRT-PCR and D1R, D5R and D4R surface protein by flow cytometry. Dopamine and the D1-like dopamine receptor agonist, SKF38393, increased CD14+CD16+ monocyte migration that was characterized as chemokinesis. To determine whether dopamine affected cell motility and adhesion, live cell imaging was used to monitor the accumulation of CD14+CD16+ monocytes on the surface of a tissue culture dish. Dopamine increased the number and the rate at which CD14+CD16+ monocytes in suspension settled to the dish surface. In a spreading assay, dopamine increased the area of CD14+CD16+ monocytes during the early stages of cell adhesion. In addition, adhesion assays showed that the overall total number of adherent CD14+CD16+ monocytes increased in the presence of dopamine. These data suggest that elevated extracellular dopamine in the CNS of HIV infected drug abusers contributes to HIV neuropathogenesis by increasing the accumulation of CD14+CD16+ monocytes in dopamine rich brain regions.

SAT0553 Correlation of the Frequency and Differentiation Potential of Osteoclast Progenitor Cells with Disease Activity and Response to Therapy in Patients with Rheumatoid Arthritis

BackgroundRheumatoid arthritis (RA) is marked by the persistent inflammation and osteodestruction, causing progressive disability. The mechanisms leading to joint destruction involve differentiation and activation of osteoclasts, multinucleated cells derived from...

36 Monocyte Subpopulations Counts and Associations with Global Longitudinal Strain in St-Elevation Myocardial Infarction Patients with Normal Ejection Fraction

IntroductionMonocytes, with 3 different subsets, are implicated in the initiation and progression of the atherosclerotic plaque contributing to plaque instability and rupture. Mon1 are the “classical” monocytes with inflammatory action,...

Leishmaniasis triggers changes in monocyte subsets in dogs. (VET2P.1048)

Abstract Peripheral blood monocytes are the largest group of circulating progenitor cells. Its functions have been revealed through the study of their subpopulations, especially in humans and mice in pathological processes. In Brazil, the parasite L. infantum is the cause of the canine visceral leishmaniasis. This study aimed to characterize subpopulations of peripheral blood monocytes from uninfected or L. infantum naturally infected dogs and compare their phenotypical and functional aspects. Blood samples were collected from uninfected and infected dogs, labeled by antibodies against different surface markers and analyzed by flow cytometry. It was observed two distinct populations according to CD14 expression: a population CD14High, constituting about 90% of the monocytes showing basophilic and horseshoe-shaped nucleus with greater phagocytic capacity, and another CD14Low, constituting about 10% of monocytes, showing less basophilic and kidney-shaped nucleus. The analysis of the other molecules showed different levels of expression between the two populations. In dogs with visceral leishmaniasis no difference in frequency was observed between populations, however there is an increase of CD14+ cells in infected dogs. We also noticed marked reduction of the expression of molecules related to the activation of monocytes, especially in the group of symptomatic dogs, indicating a possible inhibition on the capacity of these cells to control the disease.

Monocyte subset counts associations with left ventricular systolic function post ST elevation myocardial infarction

Background: Monocytes are implicated in the initiation and progression of theatherosclerotic plaque contributing to plaque instability and rupture. Little is knownof the role played by the 3 phenotypically and functionally different monocytesubpopulations in determining ventricular remodeling following ST elevation my-ocardial infarction (STEMI). Mon1 are classical inflammatory monocytes, whilstMon3 are considered reparative with fibroblast deposition ability. The function ofthe newly described Mon2 is yet to be elucidated. Method: STEMI patients (n=196, mean age 62±13 years; 72% male) treatedwith percutaneous revascularization were recruited within the first 24 hours. Pe-ripheral blood monocyte subpopulations were enumerated and characterizedusing flow cytometry after staining for CD14, CD16 and CCR2. Phenotypi-cally, monocyte subpopulations are defined as: CD14+CD16-CCR2+ (Mon1),CD14+CD16+CCR+ (Mon2) and CD14lowCD16+CCR2- (Mon3) cells. Transtho-racic 2D echocardiography was performed within 7 days and 6 months post infarctto assess ventricular volumes, mass, systolic, and diastolic functions. Results: Using linear regression analysis higher counts for Mon1, and lowercounts for Mon2 and Mon3 were significantly associated with the baseline leftventricular ejection fraction (LVEF) within seven days post infarction. At 6 monthspost STEMI lower counts of Mon2 remained positively associated with decreasedLVEF (p value= 0.002).Monocyte subsets correlation with LVEFMonocytes mean florescence Baseline left ventricular Left ventricular ejectionintensity (cells/μl) ejection fraction (%) fraction (%) at 6 months post infarctβ-value P-valueβ-value P-valueTotal Mon0.31 P<0.001 0.360.009Mon 10.019 0.020.070.62Mon 2−0.28 0.001 −0.420.002Mon 3−0.27 0.001 −0.180.21 Conclusion: Peripheral monocytes of all three subsets correlate with LVEF af-ter a myocardial infarction. High counts of the inflammatory Mon1 are associatedwith reduction in the baseline LVEF. Post remodelling, the convalescent EF wasindependently predicted by monocyte subpopulation 2. As lower counts depictednegative ventricular remodeling, this suggests a reparative role for the newly de-scribed Mon2, possibly via myofibroblast deposition and angiogenesis, in contrastto an anticipated inflammatory role.

043 MONOCYTE SUBPOPULATION COUNTS AND ASSOCIATIONS WITH LEFT VENTRICULAR EJECTION FRACTION POST ST ELEVATION MYOCARDIAL INFARCTION: Table 1

<h3>Background</h3> Monocytes are implicated in the initiation and progression of the atherosclerotic plaque contributing to plaque instability and rupture. Little is known about the role of the three phenotypically and functionally different monocyte subpopulations in determining ventricular remodelling following ST elevation myocardial infarction (STEMI). Mon1 are the ‘classical’ monocytes with inflammatory action, whilst Mon3 are considered reparative with fibroblast deposition ability. The function of the newly described Mon2 subset is yet to be fully described. <h3>Method</h3> STEMI patients (n=196, mean age 62±13 years; 72% male) treated with percutaneous revascularization were recruited within the first 24 h post-infarction. Peripheral blood monocyte subpopulations were enumerated and characterised using flow cytometry after staining for CD14, CD16 and CCR2. Phenotypically, monocyte subpopulations are defined as: CD14++CD16-CCR2+ (Mon1), CD14++CD16+CCR2+ (Mon2) and CD14+CD16++CCR2- (Mon3) cells. Transthoracic 2D echocardiography was performed within 7 days and at 6 months post infarct to assess ventricular volumes, mass, systolic, and diastolic functions as well as strain and strain rate. <h3>Results</h3> Using linear regression analysis higher counts for Mon1, and lower counts for Mon2 and Mon3 were significantly associated with the baseline left ventricular ejection fraction (LVEF) within 7 days post infarct (table&nbsp;1). At 6 months post STEMI lower counts of Mon2 remained positively associated with a decrease in LVEF at completion of remodelling (p=0.002). <h3>Conclusion</h3> Peripheral monocytes of all three subsets correlate with LVEF after a myocardial infarction. High counts of the inflammatory Mon1 are associated with the reduced baseline ejection fraction post infarction. After remodelling, the convalescent ejection fraction was independently predicted by monocyte subpopulation 2. As lower counts depicted negative ventricular remodelling, this suggests a possible myofibroblast deposition and angiogenesis role for the newly described intermediate monocyte subpopulation Mon2 as opposed to the previously anticipated inflammatory role.