Circulating myeloid-derived MMP8 in stress susceptibility and depression.

Psychosocial stress has profound effects on the body, including the immune system and the brain1,2. Although a large number of pre-clinical and clinical studies have linked peripheral immune system alterations to stress-related disorders such as major depressive disorder (MDD)3, the underlying mechanisms are not well understood. Here we show that expression of a circulating myeloid cell-specific proteinase, matrix metalloproteinase 8 (MMP8), is increased in the serum of humans with MDD as well as in stress-susceptible mice following chronic social defeat stress (CSDS). In mice, we show that this increase leads to alterations in extracellular space and neurophysiological changes in the nucleus accumbens (NAc), as well as altered social behaviour. Using a combination of mass cytometry and single-cell RNA sequencing, we performed high-dimensional phenotyping of immune cells in circulation and in the brain and demonstrate that peripheral monocytes are strongly affected by stress. In stress-susceptible mice, both circulating monocytes and monocytes that traffic to the brain showed increased Mmp8 expression following chronic social defeat stress. We further demonstrate that circulating MMP8 directly infiltrates the NAc parenchyma and controls the ultrastructure of the extracellular space. Depleting MMP8 prevented stress-induced social avoidance behaviour and alterations in NAc neurophysiology and extracellular space. Collectively, these data establish a mechanism by which peripheral immune factors can affect central nervous system function and behaviour in the context of stress. Targeting specific peripheral immune cell-derived matrix metalloproteinases could constitute novel therapeutic targets for stress-related neuropsychiatric disorders.

Neutrophil-Lymphocyte Ratio and Lymphocyte-Monocyte Ratio correlate with Chronic Prosthetic Joint Infection but are not useful markers for diagnosis.

PURPOSE: To investigate reported correlations between Neutrophil-to-Lymphocyte (NLR) and Lymphocyte-to-Monocyte (LMR) ratios and their value in diagnosis of chronic prosthetic joint infection (PJI) in a large cohort of patients from a single specialist hospital. METHODS: Diagnostic aspirations of 362 patients under investigation for PJI were identified. Of the included patients 185 patients received a final diagnosis of PJI and 177 were classed as aseptic. Established criteria (ICM 2018) were employed to define PJI. Included in the analysis are differential white cell counts, C-Reactive Protein (CRP), Synovial Leukocyte Count, Synovial Alpha-defensin ELISA and Synovial Leukocyte esterase activity. Receiver-operator characteristic (ROC) curves were calculated for each of the available diagnostic tests together with the corresponding area under the curve values (AUC). Youden's index was utilized to identify the optimal diagnostic threshold point for the NLR and LMR. Other diagnostic tests were evaluated as per the threshold values previously defined in the literature and specified in the ICM criteria. RESULTS: Using Youden's Index to identify the optimal NLR cut-off within our cohort we established a value of 2.93. This yielded a sensitivity of 0.60 and specificity of 0.64. The area under the curve (AUC) of a receiving operator characteristics (ROC) curve was 0.625. Regarding the LMR the results demonstrate similar findings; a positive correlation with a diagnosis of infection but poor sensitivity and specificity. The AUC for LMR was 0.633 and was not superior to NLR (P = 0.753). CONCLUSIONS: There is a significant correlation between higher Neutrophil-Lymphocyte and Lymphocyte-Monocyte ratios, and a diagnosis of PJI. The sensitivity and specificity of this calculation is poor and the does not add value to the diagnostic algorithm for PJI. LEVEL OF EVIDENCE: Level III Retrospective Cohort analysis.

Monocyte to lymphocyte ratio and hemoglobin level to predict tuberculosis after antiretroviral therapy initiation.

OBJECTIVE: To determine the performance of the baseline monocyte to lymphocyte ratio (MLR), baseline anemia severity and combination of these biomarkers, to predict tuberculosis (TB) incidence in people with HIV (PWH) after antiretroviral therapy (ART) initiation. DESIGN: Multicenter, retrospective cohort study. METHODS: We utilized the data from study A5175 (Prospective Evaluation of Antiretroviral Therapy in Resource-limited Settings: PEARLS). We assessed the utility of MLR, anemia severity and in combination, for predicting TB in the first year after ART. Cox regression was used to assess associations of MLR and anemia with incident TB. Harrell's C index was used to describe single model discrimination. RESULTS: A total of 1455 participants with a median age of 34 [interquartile range (IQR) 29, 41] were included. Fifty-four participants were diagnosed with TB. The hazard ratio (HR) for incident TB was 1.77 [95% confidence interval (CI) 1.01-3.07]; P  = 0.04 for those with MLR ≥0.23. The HR for mild/mod anemia was 3.35 (95% CI 1.78-6.29; P  < 0.001) and 18.16 (95% CI 5.17-63.77; P  < 0.001) for severe anemia. After combining parameters, there were increases in adjusted HR (aHR) for MLR ≥0.23 to 1.83 (95% CI 1.05-3.18), and degrees of anemia to 3.38 (95% CI 1.80-6.35) for mild/mod anemia and 19.09 (95% CI 5.43-67.12) for severe anemia. CONCLUSIONS: MLR and hemoglobin levels which are available in routine HIV care can be used at ART initiation for identifying patients at high risk of developing TB disease to guide diagnostic and management decisions.

Correlation between C-reactive protein and the inflammatory ratios in acute schizophrenia inpatients: are they associated?

C-reactive protein (CRP) and inflammatory ratios have been proposed to study immune dysregulation in schizophrenia. Nevertheless, links between CRP and inflammatory ratios in acute SCZ inpatients have been understudied. This study investigated the relationship between CRP and inflammatory ratios (Neutrophil-Lymphocyte Ratio [NRL], Platelet-Lymphocyte Ratio [PLR], Monocyte-Lymphocyte ratio [MLR] and Basophil-Lymphocyte Ratio [BLR]) in a total of 698 acute SCZ inpatients; and analysed how this relationship is affected by sex and type of episode. CRP correlated with NLR (rs = 0.338, p < 0.001), PLR (rs = 0.271, p < 0.001) and MLR (rs = 0.148, p < 0.001) but not with BLR (rs = 0.059, p = 0.121). Multiple lineal regression analysis showed that high levels of NLR, MLR and PLR but not BLR were independently associated with high CRP levels. No sex-related variations were found. Significant associations were maintained for NLR and MLR in first-episode and multiepisode SCZ, although the strength of the association was stronger in multiepisode SCZ. Again, no sex-related differences were found in these associations. In conclusion, inflammatory ratios were low to moderately associated with CRP in acute SCZ inpatients. NLR and multiepisode SCZ showed the highest associations with CRP. Future studies should consider inflammatory ratios not as a substitute for CRP but as a complementary biomarker.

Single-cell transcriptome profiling of sepsis identifies HLA-DRlowS100Ahigh monocytes with immunosuppressive function.

BACKGROUND: Sustained yet intractable immunosuppression is commonly observed in septic patients, resulting in aggravated clinical outcomes. However, due to the substantial heterogeneity within septic patients, precise indicators in deciphering clinical trajectories and immunological alterations for septic patients remain largely lacking. METHODS: We adopted cross-species, single-cell RNA sequencing (scRNA-seq) analysis based on two published datasets containing circulating immune cell profile of septic patients as well as immune cell atlas of murine model of sepsis. Flow cytometry, laser scanning confocal microscopy (LSCM) imaging and Western blotting were applied to identify the presence of S100A9+ monocytes at protein level. To interrogate the immunosuppressive function of this subset, splenic monocytes isolated from septic wild-type or S100a9-/- mice were co-cultured with naïve CD4+ T cells, followed by proliferative assay. Pharmacological inhibition of S100A9 was implemented using Paquinimod via oral gavage. RESULTS: ScRNA-seq analysis of human sepsis revealed substantial heterogeneity in monocyte compartments following the onset of sepsis, for which distinct monocyte subsets were enriched in disparate subclusters of septic patients. We identified a unique monocyte subset characterized by high expression of S100A family genes and low expression of human leukocyte antigen DR (HLA-DR), which were prominently enriched in septic patients and might exert immunosuppressive function. By combining single-cell transcriptomics of murine model of sepsis with in vivo experiments, we uncovered a similar subtype of monocyte significantly associated with late sepsis and immunocompromised status of septic mice, corresponding to HLA-DRlowS100Ahigh monocytes in human sepsis. Moreover, we found that S100A9+ monocytes exhibited profound immunosuppressive function on CD4+ T cell immune response and blockade of S100A9 using Paquinimod could partially reverse sepsis-induced immunosuppression. CONCLUSIONS: This study identifies HLA-DRlowS100Ahigh monocytes correlated with immunosuppressive state upon septic challenge, inhibition of which can markedly mitigate sepsis-induced immune depression, thereby providing a novel therapeutic strategy for the management of sepsis.

Diagnostic value of monocyte-lymphocyte ratio and red cell distribution width- lymphocyte ratio against other biomarkers in children with acute appendicitis, cross-sectional study.

Our study aims to ascertain the diagnostic value of the Monocyte-lymphocyte ratio (MLR) and red cell distribution width (RDW)-lymphocyte ratio (RLR) by comparing them with other biomarkers in distinguishing patients with and without acute appendicitis (AA). A total of 223 children were recruited in the study conducted according to the Cross-Sectional Study design. Patients under 18 years were assigned to 3 groups; AA, nonspecific abdominal pain (NAP), and a control group. According to the outcome of our research, while C-reactive protein (CRP), white blood cell (WBC), neutrophil count (NEU), neutrophil to lymphocyte ratio (NLR), and MLR had excellent diagnostic power, RLR had acceptable diagnostic power, and platelet to lymphocyte ratio (PLR) had only fair diagnostic power. MLR and NLR, which are simple, inexpensive, and easily accessible parameters, can be recommended to be used together with other biomarkers in diagnosing AA in children.

Association of C-reactive Protein/Albumin, Procalcitonin/Albumin, Platelet/Lymphocyte, and Lymphocyte/Monocyte Ratio with Mortality in Hospitalised COVID-19 Patients.

OBJECTIVE: To investigate and compare complete blood count and biochemistry parameters such as c-reactive protein/albumin (CRP/ALB) ratio, procalcitonin/albumin (PRO/ALB) ratio, lymphocyte/monocyte (LYM/MON) ratio, platelet/lymphocyte (PLT/LYM) ratio of the recovered/deceased, and ICU (intensive care unit) /ward patients with COVID-19. STUDY DESIGN: An observational study. PLACE AND DURATION OF STUDY: Department of Internal Medicine, Sakarya University Training and Research Hospital, Turkey, from April 2020 to January 2021. METHODOLOGY: The study was conducted with 590 diagnosed patients with COVID-19. The patients were divided into 2 groups as deceased (n = 294) /survivor (n = 296) and those in need of ICU (n= 418) /ward (n = 172). The information was obtained from the hospital information system and analysed retrospectively. The relationships of crp/alb, pro/alb, lym/mon, and PLT/LYM ratios with patient groups were investigated. RESULTS: Of the total 590 patients in the study, 358 (60.6%) were males. The total mean age was 65.63 ±14.9 years. The mean age of survivor and deceased groups was 71.32±10.9 and 59.97±16.2 years, respectively (p.

Poor performance of monocyte-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio, and fibrinogen when screening for occult infection among patients with sequelae of suppurative hip arthritis before total hip arthroplasty.

BACKGROUND: Total hip arthroplasty (THA) is considered the best treatment for sequelae of suppurative hip arthritis, but such patients are more likely to have occult infection and therefore to suffer post-operative periprosthetic joint infection. Our study examined (1) the occult infection rate among patients with sequelae of suppurative hip arthritis, and whether (2) neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), or fibrinogen levels can be used to screen such patients for occult infection before THA. METHODS: We retrospectively enrolled 428 patients who underwent primary THA at our hospital between 2010 and 2021, of whom 31 had occult infection and 397 did not. The maximum sensitivity and specificity were determined for the three indicators using receiver operating characteristic curves, and positive and negative predictive values were calculated. RESULTS: Patients with occult infection showed significantly higher erythrocyte sedimentation rate (ESR) and higher levels of C-reactive protein (CRP) and fibrinogen than those without occult infection. The various potential indicators gave the following areas under the receiver operating characteristic curves: ESR, 0.586; CRP, 0.599; interleukin-6, 0.651; NLR, 0.506; MLR, 0.600; and fibrinogen, 0.589. Sensitivity and specificity were as follows: ESR, 30.8% and 92.5%; CRP, 50.0% and 70.2%; interleukin-6, 57.7% and 67.5%; NLR, 46.7% and 62.9%; MLR, 60.0% and 61.7%; and fibrinogen, 43.3% and 81.7%. CONCLUSION: The rate of occult infection was 7.24% among our patients. ESR, NLR, MLR, and levels of CRP, interleukin-6, and fibrinogen may be unreliable for screening such patients for occult infection before THA according to sensitivity and specificity.

Usefulness of monocyte distribution width (MDW) as a sepsis biomarker.

Sepsis is one of the main causes of mortality in the emergency department (ED), due to the fact that signs and symptoms are common to other acute diseases, and this can result in delayed detection. This diagnostic complexity has a huge impact on an entity in which early recognition determined treatment, as wells as enhance the patient's prognosis. Therefore, it is crucial to improve early identification. Different analytical tools arise from this approach, such as biomarkers: procalcitonin, C-reactive protein or MR-proadrenomedullin. In this review we will focus on a newer biomarker, the monocyte distribution width. The main objectives are to evaluate the usefulness of monocyte distribution width (MDW) in sepsis identification in ED, its limitations, and to compare it with other biomarker.

Nanoplastics affect the inflammatory cytokine release by primary human monocytes and dendritic cells.

So far, the human health impacts of nano- and microplastics are poorly understood. Thus, we investigated whether nanoplastics exposure induces inflammatory processes in primary human monocytes and monocyte-derived dendritic cells. We exposed these cells in vitro to nanoplastics of different shapes (irregular vs. spherical), sizes (50-310 nm and polydisperse mixtures) and polymer types (polystyrene; polymethyl methacrylate; polyvinyl chloride, PVC) using concentrations of 30-300 particles cell-1. Our results show that irregular PVC particles induce the strongest cytokine release of these nanoplastics. Irregular polystyrene triggered a significantly higher pro-inflammatory response compared to spherical nanoplastics. The contribution of chemicals leaching from the particles was minor. The effects were concentration-dependent but varied markedly between cell donors. We conclude that nanoplastics exposure can provoke human immune cells to secrete cytokines as key initiators of inflammation. This response is specific to certain polymers (PVC) and particle shapes (fragments). Accordingly, nanoplastics cannot be considered one homogenous entity when assessing their health implications and the use of spherical polystyrene nanoplastics may underestimate their inflammatory effects.

Comprehensive Immune Profiling Reveals CD56+ Monocytes and CD31+ Endothelial Cells Are Increased in Severe COVID-19 Disease.

Immune response dysregulation plays a key role in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogenesis. In this study, we evaluated immune and endothelial blood cell profiles of patients with coronavirus disease 2019 (COVID-19) to determine critical differences between those with mild, moderate, or severe COVID-19 using spectral flow cytometry. We examined a suite of immune phenotypes, including monocytes, T cells, NK cells, B cells, endothelial cells, and neutrophils, alongside surface and intracellular markers of activation. Our results showed progressive lymphopenia and depletion of T cell subsets (CD3+, CD4+, and CD8+) in patients with severe disease and a significant increase in the CD56+CD14+Ki67+IFN-γ+ monocyte population in patients with moderate and severe COVID-19 that has not been previously described. Enhanced circulating endothelial cells (CD45-CD31+CD34+CD146+), circulating endothelial progenitors (CD45-CD31+CD34+/-CD146-), and neutrophils (CD11b+CD66b+) were coevaluated for COVID-19 severity. Spearman correlation analysis demonstrated the synergism among age, obesity, and hypertension with upregulated CD56+ monocytes, endothelial cells, and decreased T cells that lead to severe outcomes of SARS-CoV-2 infection. Circulating monocytes and endothelial cells may represent important cellular markers for monitoring postacute sequelae and impacts of SARS-CoV-2 infection during convalescence and for their role in immune host defense in high-risk adults after vaccination.

Usefulness of peripheral blood monocyte count to predict relapse in patients with inflammatory bowel disease: a prospective longitudinal cohort study

Background: monocytes play an important role in the pathogenesis of inflammatory bowel disease but data are scarce regarding activity biomarkers, above all in patients under biologic therapies.Objective: the aim of this study was to evaluate the value of monocyte measurements in predicting flares in inflammatory bowel disease patients under maintenance treatment with anti-TNF.Methods: a prospective, observational cohort study was designed. Relapse was defined as a Harvey-Bradshawscore > 4 in Crohn’s disease, and a partial Mayo score ≥ 2 in ulcerative colitis. Monocyte concentration was quantifiedat 4-month intervals for twelve months. A total of 95 consecutive patients were included. Median age was 42 years,50.5 % were female, and 75 % had Crohn’s disease.Results: sixteen months after inclusion, 65 (68.4 %) patients remained in clinical remission. Mean monocyte count preceding a relapse was 563 (standard deviation: 144) compared to 405 (standard deviation: 177) in patients who remained in remission. Final monocyte count was significantly different between relapse and remission in Crohn’s disease (0.82; 95 % CI: 0.71-0.90; p < 0.005). According to the multivariate analysis, only monocytes and fecal calprotectin were related to more relapses. (AU)

Usefulness of peripheral blood monocyte count to predict relapse in patients with inflammatory bowel disease: a prospective longitudinal cohort study.

BACKGROUND: monocytes play an important role in the pathogenesis of inflammatory bowel disease but data are scarce regarding activity biomarkers, above all in patients under biologic therapies. OBJECTIVE: the aim of this study was to evaluate the value of monocyte measurements in predicting flares in inflammatory bowel disease patients under maintenance treatment with anti-TNF. METHODS: a prospective, observational cohort study was designed. Relapse was defined as a Harvey-Bradshaw score > 4 in Crohn's disease, and a partial Mayo score ≥ 2 in ulcerative colitis. Monocyte concentration was quantified at 4-month intervals for twelve months. A total of 95 consecutive patients were included. Median age was 42 years, 50.5 % were female, and 75 % had Crohn's disease. RESULTS: sixteen months after inclusion, 65 (68.4 %) patients remained in clinical remission. Mean monocyte count preceding a relapse was 563 (standard deviation: 144) compared to 405 (standard deviation: 177) in patients who remained in remission. Final monocyte count was significantly different between relapse and remission in Crohn's disease (0.82; 95 % CI: 0.71-0.90; p < 0.005). According to the multivariate analysis, only monocytes and fecal calprotectin were related to more relapses. CONCLUSION: in conclusion, in inflammatory bowel disease patients under anti-TNF therapy, repeat monocyte counts could help monitor patients, at least in Crohn's disease.

Inflammation protein quantification by multiple reaction monitoring mass spectrometry in lipopolysaccharide-stimulated THP-1 cells.

RATIONALE: Inflammation is a cascade of events mediated by a cytokine network triggering the cellular response. In order to monitor the modulation of the crucial inflammatory proteins, e.g., Tumour Necrosis Factor-α (TNF-α), Interferon-γ (INF-γ), Interleukin-8 (IL-8) and Interleukin-10 (IL-10), upon stimulation with endotoxins, differentiated and undifferentiated THP-1 cells were treated with lipopolysaccharides (LPSs) from E. coli, key cell wall components of Gram-negative bacteria. METHODS: The multiple reaction monitoring mass spectrometry (MRM-MS) method was optimized by using the standard proteins to be quantified, in order to construct external calibration curves and define the analytical parameters. The developed method was used to quantify the above-mentioned inflammatory proteins in THP-1 differentiated cells upon stimulation with LPSs with high accuracy, sensitivity, and robustness. RESULTS: The analysis of such proteins in MRM mode allowed the kinetics of stimulation along the time up to 24 h to be followed and the MS results were found to be comparable with those obtained by Western-blotting. A significant increase in TNF-α release triggered a cascade mechanism leading to the production of INF-γ and IL-8. IL-10, instead, was found to be constant throughout the process. CONCLUSIONS: The developed MRM-MS method allowed the quantification of TNF-α, INF-γ, IL-8 and IL-10 along a time-course from 2 to 24 h. Hence, a trace of the kinetics of the inflammatory response in THP-1 cells upon stimulation with E. coli LPSs was obtained. Finally, the extensibility of the developed MRM method to serum samples and other matrices demonstrated the versatility of the approach and the possibility to quantify multiple target proteins in different biological samples by using a few microliters in a single analysis.

Differential response of immobile (pneumocytes) and mobile (monocytes) barriers against 2 types of metal oxide nanoparticles.

BACKGROUND: Inhaled nanoparticles (NPs) challenges mobile and immobile barriers in the respiratory tract, which can be represented by type II pneumocytes (immobile) and monocytes (mobile) but what is more important for biological effects, the cell linage, or the type of nanoparticle? Here, we addressed these questions and we demonstrated that the type of NPs exerts a higher influence on biological effects, but cell linages also respond differently against similar type of NPs. DESIGN: Type II pneumocytes and monocytes were exposed to tin dioxide (SnO2) NPs and titanium dioxide (TiO2) NPs (1, 10 and 50 µg/cm2) for 24 h and cell viability, ultrastructure, cell granularity, molecular spectra of lipids, proteins and nucleic acids and cytoskeleton architecture were evaluated. RESULTS: SnO2 NPs and TiO2 NPs are metal oxides with similar physicochemical properties. However, in the absence of cytotoxicity, SnO2 NPs uptake was low in monocytes and higher in type II pneumocytes, while TiO2 NPs were highly internalized by both types of cells. Monocytes exposed to both types of NPs displayed higher number of alterations in the molecular patterns of proteins and nuclei acids analyzed by Fourier-transform infrared spectroscopy (FTIR) than type II pneumocytes. In addition, cells exposed to TiO2 NPs showed more displacements in FTIR spectra of biomolecules than cells exposed to SnO2 NPs. Regarding cell architecture, microtubules were stable in type II pneumocytes exposed to both types of NPs but actin filaments displayed a higher number of alterations in type II pneumocytes and monocytes exposed to SnO2 NPs and TiO2 NPs. NPs exposure induced the formation of large vacuoles only in monocytes, which were not seen in type II pneumocytes. CONCLUSIONS: Most of the cellular effects are influenced by the NPs exposure rather than by the cell type. However, mobile, and immobile barriers in the respiratory tract displayed differential response against SnO2 NPs and TiO2 NPs in absence of cytotoxicity, in which monocytes were more susceptible than type II pneumocytes to NPs exposure.

Can Routine Blood Biochemistry Parameters be Predictive Prognostic Marker(s) in Operated Patients with Meningioma WHO Grade 1?

Background Today, there is a need for new and independent additional advanced markers that can predict the prognosis of meningioma patients, postoperatively. The present study aimed to find out postoperative short-term prognostic markers in patients with meningioma using their demographic data and routine blood biochemistry findings evaluated preoperatively. Methods The Glasgow Coma Scale (GCS), and Glasgow Outcome Scale (GOS) scores of the patients were recorded. Additionally, preoperatively obtained serum glucose, Creactive protein (CRP), sodium, potassium, creatinine, blood urea nitrogen, aspartate aminotransferase (AST), alanine aminotransferase, and hemoglobin level values, platelet, leukocyte, neutrophil, lymphocyte, eosinophil, basophil, andmonocyte count results, erythrocyte sedimentation rate (ESR), neutrophil-lymphocyte ratio, plateletlymphocyte ratio (PLR) and lymphocyte-monocyte ratio (LMR) values were evaluated. Results In the present study, 23 operated patients with meningioma World Health Organization (WHO) grade 1 (17 females, 6 males) were included. Correlation test results revealed that the GCS score, platelet count, and serum potassium level values could directly predict the short-term prognosis of these patients. Additionally, these test results suggested that the lymphocyte, monocyte, and eosinophil count values, PLR, LMR, ESR, serum glucose, CRP, and AST level values could be indirect markers in predicting the short-term prognosis. However, likelihood ratio test results revealed that only monocyte count value, LMR value, and serum CRP level value could be the markers for prediction of the short-term prognosis. Conclusion At the end of the present study, it was concluded that the monocyte count value, LMR value, and serum CRP level value could be the best markers in predicting the short-term prognosis of the operated meningioma patients.

Sex differences in concentrations of HMGB1 and numbers of pigmented monocytes in infants and young children with malaria.

Sex remains a key biological variable affecting human innate and adaptive immune responses to infection and in pathogenesis of diseases. In malaria, females demonstrate higher concentrations of antibodies and rates of severe adverse events and mortality following malaria vaccination. Although monocytes/macrophages play a crucial role in disease and protection in malaria, no studies have investigated sex differences in their functions in production of proinflammatory cytokines and chemokines in malaria-infected subjects. Here, we show significant sex differences in serum concentrations of HMGB1, a non-histone chromatin-associated protein, and numbers of pigmented monocytes, which are both markers of severe malaria, in infants and young children <5 years old from a malaria endemic region in Northern Uganda. Female infants and young children with clinical malaria had significantly higher HMGB1 concentrations than males, and female infants and young children with asymptomatic malaria had significantly lower numbers of pigmented monocytes than males with asymptomatic malaria. There was (1) a significant correlation between HMGB1 concentrations and pigmented monocyte numbers in female but not male infants; and (2) a significant correlation between HMGB1 concentrations and parasite densities in female but not male infants. These findings suggest that female infants and young children with clinical malaria might be at a greater risk of morbidity characterized by higher serum HMGB1 levels.

Monocyte TREM-1 Levels Associate With Anti-TNF Responsiveness in IBD Through Autophagy and Fcγ-Receptor Signaling Pathways.

The expression of Triggering Receptor Expressed on Myeloid cells (TREM)-1 has been described as a predictive marker for anti-Tumor Necrosis Factor (TNF)-α monoclonal antibody (mAb) therapy responsiveness in patients with inflammatory bowel disease (IBD). Here we investigated expression of TREM-1 specifically in CD14+ monocytes in relation to anti-TNF response. The pretreatment TREM-1 expression levels of CD14+ monocytes of Crohn's disease (CD) patients were predictive of outcome to anti-TNF mAb therapy, with low TREM-1 expression associated with response to anti-TNF. FACSorting of CD14+ monocytes with different TREM-1 levels showed that differentiation towards regulatory CD206+ M2 type macrophages by anti-TNF was suppressed in CD14+ monocytes with high TREM-1 expression. Activity of the Fcγ-Receptor and autophagy pathway, both necessary for M2 type differentiation and the response to anti-TNF, were decreased in CD14+ monocytes with high expression of TREM-1. We confirmed that the activity of the Fcγ-Receptor pathway was decreased in the CD patients that did not respond to anti-TNF therapy and that it was negatively correlated with TREM-1 expression levels in the CD patient cohort. In conclusion, our results indicate that TREM-1 expression levels in CD14+ monocytes associate with decreased autophagy and FcγR activity resulting in decreased differentiation to M2 type regulatory macrophages upon anti-TNF mAb treatment, which may explain anti-TNF non-response in IBD patients with high expression levels of TREM-1.

Targeting Immune Cell Metabolism in the Treatment of Inflammatory Bowel Disease.

The cells of the immune system are highly dynamic, constantly sensing and adapting to changes in their surroundings. Complex metabolic pathways govern leukocytes' ability to fine-tune their responses to external threats. Mammalian target of rapamycin complex 1 and hypoxia inducible factor are important hubs of these pathways and play a critical role coordinating cell activation and proliferation and cytokine production. For this reason, these molecules are attractive therapeutic targets in inflammatory disease. Insight into perturbations in immune cell metabolic pathways and their impact on inflammatory bowel disease (IBD) progression are starting to emerge. However, it remains to be determined whether the aberrations in immune metabolism that occur in gut resident immune cells contribute to disease pathogenesis or are reflected in the peripheral blood of patients with IBD. In this review, we explore what is known about the metabolic profile of T cells, monocytes, macrophages, dendritic cells, and natural killer cells in IBD and discuss the potential of manipulating immune cell metabolism as a novel approach to treating IBD.