Antigen-presenting Monocytes Research Articles

Factors associated with genetic markers for rotator cuff disease in patients with atraumatic rotator cuff tears.

For atraumatic rotator cuff tears, genetics contributes to symptomatic tear risk and may influence rotator cuff healing after surgical repair. But little is known about how genetic factors influence rotator cuff tear patient characteristics at presentation. We collected saliva samples for genotyping from atraumatic rotator cuff tear patients. We examined nine single nucleotide polymorphisms (SNPs) associated with cuff tears in prior literature. We estimated associations of SNP dosage with (1) age at tear diagnosis, (2) bilateral atraumatic tear prevalence, and (3) tear size. Linear regression was used to estimate associations with diagnosis age adjusted for sex and principal components. Logistic regression and ordinal logistic regression were used to estimate associations with bilateral tear prevalence and tear size category, respectively, adjusting for age, sex, and principal components. Of 344 eligible patients, 336 provided sufficient samples for genotyping. Median age at tear diagnosis was 61, 22% (N = 74) had bilateral atraumatic tears, and 9% (N = 29) had massive tears. SNP rs13107325 in the SLC39A8 gene and rs11850957 in the STXBP6 gene were associated with younger diagnosis age even after accounting for multiple comparisons (rs13107325: -4 years, 95% CI = -6.5, -1.4; rs11850957: -2.7 years, 95% CI = -4.3, -1.1). No other significant associations were observed with diagnosis age, tear size, or bilateral tear prevalence. SLC39A8 encodes a Mn transporter. STXBP6 may play a role in inflammatory responses by altering phagocytosis and antigen presentation of monocytes and macrophages. Further research is needed to determine if genetic markers can be used alongside patient characteristics to aid in identifying optimal surgical repair candidates.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

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.

A CCL5 chemokine trail laid down by migratory dendritic cells directs CCR5 +antigen-presenting monocytes into draining lymph nodes

Abstract Antigen presenting dendritic cells (DCs) and monocytes capture and transport antigens from barrier tissues for presentation to antigen-specific T cells in the draining-lymph nodes (LNs). While DCs enter LNs through afferent lymphatics in a CCR7-dependent manner, how exactly antigen-carrying monocytes reach LNs is less clear since monocytes do not express CCR7 and can also enter LNs via the bloodstream. In steady state, and following injection of several PAMPs, scRNA-seq data on LN mononuclear phagocytes identified LN resident versus migratory type 1 and type 2 conventional (c)DCs despite downregulation of DC subset-defining transcripts, such as Xcr1, Clec9a, H2-Ab1, Sirpa, and Clec10a on migratory cDCs. Migratory cDCs gained expression of transcripts controlling cellular migration such as Ccr7, Ccl17, Ccl22, and Ccl5, while migratory monocytes expressed Ccr5 without Ccr7. Using two tracking methods and a gating strategy that clearly distinguishes migratory CD88 hiCD26 lomonocytes from CD88 −CD26 hicDCs, we found that both captured antigens in the lung and migrated to lung draining LNs. Using global and mixed-chimeric Ccl5-, Ccr2-, Ccr5-, Ccr7-, and Batf3-deficient mice, we found that CCR5 +monocytes follow CCL5-secreting migratory cDCs to reach the draining LN via lymphatic vessels. In a model of asthma, such recruited monocytes regulated the induction of type 2 immunity. Overall, our data suggest that CCL5-secreting migratory cDCs lay down the chemokine trail for CCR5+ antigenpresenting monocytes to reach draining lymph nodes and regulate adaptive immunity. This work was supported by National Institutes of Health grants R01 HL115334, R01 HL135001, and R35 HL155458 (CVJ)

Vaccination Ameliorates Cellular Inflammatory Responses in SARS-CoV-2 Breakthrough Infections.

Data on cellular immune responses in persons with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection following vaccination are limited. The evaluation of these patients with SARS-CoV-2 breakthrough infections may provide insight into how vaccinations limit the escalation of deleterious host inflammatory responses. We conducted a prospective study of peripheral blood cellular immune responses to SARS-CoV-2 infection in 21 vaccinated patients, all with mild disease, and 97 unvaccinated patients stratified based on disease severity. We enrolled 118 persons (aged 50 years [SD 14.5 years], 52 women) with SARS-CoV-2 infection. Compared to unvaccinated patients, vaccinated patients with breakthrough infections had a higher percentage of antigen-presenting monocytes (HLA-DR+), mature monocytes (CD83+), functionally competent T cells (CD127+), and mature neutrophils (CD10+); and lower percentages of activated T cells (CD38+), activated neutrophils (CD64+), and immature B cells (CD127+CD19+). These differences widened with increased disease severity in unvaccinated patients. Longitudinal analysis showed that cellular activation decreased over time but persisted in unvaccinated patients with mild disease at 8-month follow-up. Patients with SARS-CoV-2 breakthrough infections exhibit cellular immune responses that limit the progression of inflammatory responses and suggest mechanisms by which vaccination limits disease severity. These data may have implications for developing more effective vaccines and therapies. Clinical Trials Registration. NCT04401449.

Translatome analyses by bio-orthogonal non-canonical amino acid labeling reveal that MR1-activated MAIT cells induce an M1 phenotype and antiviral programming in antigen-presenting monocytes.

MAIT cells are multifunctional innate-like effector cells recognizing bacterial-derived vitamin B metabolites presented by the non-polymorphic MHC class I related protein 1 (MR1). However, our understanding of MR1-mediated responses of MAIT cells upon their interaction with other immune cells is still incomplete. Here, we performed the first translatome study of primary human MAIT cells interacting with THP-1 monocytes in a bicellular system. We analyzed the interaction between MAIT and THP-1 cells in the presence of the activating 5-OP-RU or the inhibitory Ac-6-FP MR1-ligand. Using bio-orthogonal non-canonical amino acid tagging (BONCAT) we were able to enrich selectively those proteins that were newly translated during MR1-dependent cellular interaction. Subsequently, newly translated proteins were measured cell-type-specifically by ultrasensitive proteomics to decipher the coinciding immune responses in both cell types. This strategy identified over 2,000 MAIT and 3,000 THP-1 active protein translations following MR1 ligand stimulations. Translation in both cell types was found to be increased by 5-OP-RU, which correlated with their conjugation frequency and CD3 polarization at MAIT cell immunological synapses in the presence of 5-OP-RU. In contrast, Ac-6-FP only regulated a few protein translations, including GSK3B, indicating an anergic phenotype. In addition to known effector responses, 5-OP-RU-induced protein translations uncovered type I and type II Interferon-driven protein expression profiles in both MAIT and THP-1 cells. Interestingly, the translatome of THP-1 cells suggested that activated MAIT cells can impact M1/M2 polarization in these cells. Indeed, gene and surface expression of CXCL10, IL-1β, CD80, and CD206 confirmed an M1-like phenotype of macrophages being induced in the presence of 5-OP-RU-activated MAIT cells. Furthermore, we validated that the Interferon-driven translatome was accompanied by the induction of an antiviral phenotype in THP-1 cells, which were found able to suppress viral replication following conjugation with MR1-activated MAIT cells. In conclusion, BONCAT translatomics extended our knowledge of MAIT cell immune responses at the protein level and discovered that MR1-activated MAIT cells are sufficient to induce M1 polarization and an anti-viral program of macrophages.

Monocyte antigen-presenting capacity to iNKT cells is influenced by the blood collection conditions

It is widely accepted that different blood collection conditions, including anticoagulants, influence leukocyte phenotype and function. Buffy Coats originated from a donated whole blood bag unit are commonly used in immunological research as a source of leukocytes. They are a residual product of healthy donor whole blood processing. The preservative solution present in the blood bag unit and consequently in the derived Buffy Coat is Citrate-Phosphate-Dextrose (CPD), in which citrate is the anticoagulant. There is a lack of information on the possible difference in the functionality of leukocytes from Buffy Coats originated from a blood bag unit vs leukocytes isolated from blood collection tubes with various anticoagulants.Herein, we aimed at studying monocyte function when the monocytes are isolated from Buffy Coats originated from a blood bag unit vs blood collection tube containing EDTA, CPD with adenine (CPDA), or sodium citrate. The function of monocytes, isolated 20 h after blood collection, to present lipid antigens to invariant Natural Killer T (iNKT) cells was investigated. iNKT cells are activated by lipids bound to CD1d, a non-polymorphic MHC-class I-like molecule, present on the surface of antigen-presenting cells.A striking result showed that monocytes isolated from EDTA blood tubes have a lower capacity to present lipid antigens to iNKT cells than monocytes isolated from Buffy Coats originated from a blood bag unit. No differences were found between monocytes isolated from sodium citrate or CPDA and the ones isolated from Buffy Coats originated from a blood bag unit. This was accompanied by a decrease in viability of the EDTA-isolated monocytes. Expression of the surface markers CD1d and CD86 was higher for monocytes isolated from EDTA than those isolated from Buffy Coats.In conclusion, EDTA-containing blood tubes are not the ideal choice of anticoagulant for monocyte antigen presentation assays. We advise that the blood collection condition and the time between biospecimen collection and analysis should be carefully considered when designing experimental procedures.

Immune response and homeostasis mechanism following administration of BBIBP-CorV SARS-CoV-2 inactivated vaccine

The BBIBP-CorV severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivated vaccine has been authorized for emergency use and widely distributed. We used single-cell transcriptome sequencing to characterize the dynamics of immune responses to the BBIBP-CorV inactivated vaccine. In addition to the expected induction of humoral immunity, we found that the inactivated vaccine induced multiple, comprehensive immune responses, including significantly increased proportions of CD16+ monocytes and activation of monocyte antigen presentation pathways; Tcell activation pathway upregulation in CD8+ Tcells, along with increased activation of CD4+ Tcells; significant enhancement of cell-cell communications between innate and adaptive immunity; and the induction of regulatory CD4+ Tcells and co-inhibitory interactions to maintain immune homeostasis after vaccination. Additionally, comparative analysis revealed higher neutralizing antibody levels, distinct expansion of naive Tcells, a shared increased proportion of regulatory CD4+ Tcells, and upregulated expression of functional genes in booster dose recipients with a longer interval after the second vaccination. Our research will support a comprehensive understanding of the systemic immune responses elicited by the BBIBP-CorV inactivated vaccine, which will facilitate the formulation of better vaccination strategies and the design of new vaccines.

An immunotherapy response prediction model derived from proliferative CD4+ T cells and antigen-presenting monocytes in ccRCC.

Most patients with clear cell renal cell carcinoma (ccRCC) have an impaired response to immune checkpoint blockade (ICB) therapy. Few biomarkers can predict responsiveness, and there is insufficient evidence to extend them to ccRCC clinical use. To explore subtypes and signatures of immunocytes with good predictive performance for ICB outcomes in the ccRCC context, we reanalyzed two ccRCC single-cell RNA sequencing (scRNA-seq) datasets from patients receiving ICB treatment. A subtype of proliferative CD4+ T cells and regulatory T cells and a subtype of antigen-presenting monocytes that have good predictive capability and are correlated with ICB outcomes were identified. These findings were corroborated in independent ccRCC ICB pretreatment bulk RNA-seq datasets. By incorporating the cluster-specific marker genes of these three immunocyte subtypes, we developed a prediction model, which reached an AUC of 93% for the CheckMate cohort (172 samples). Our study shows that the ICB response prediction model can serve as a valuable clinical decision-making tool for guiding ICB treatment of ccRCC patients.

Role of DNA-LL37 complexes in the activation of plasmacytoid dendritic cells and monocytes in subjects with type 1 diabetes

Initiation of type 1 diabetes (T1D) is marked by the infiltration of plasmacytoid dendritic cells (pDCs) and monocytes in pancreatic islets. Dying beta cells release self-DNA, which forms complexes with antimicrobial peptide, LL37, and its delayed clearance can activate pDCs and monocytes. Here, we studied the phenotypic effects of DNA-LL37 complexes on pDCs and monocytes in 55 recently diagnosed T1D and 25 healthy control (HC) subjects. Following in vitro stimulation with DNA-LL37 complexes, T1D group demonstrated higher frequency and mean fluorescence intensity (MFI) of pDCs expressing IFN-α. Similarly, the monocytes in T1D group showed an increase in MFI of IFN-α. Post-stimulation, an increase in the antigen presentation and co-stimulatory ability of pDCs and monocytes was observed in T1D group, as indicated by higher expression of HLA-DR, CD80 and CD86. Upon co-culture, the stimulated monocytes and pDCs, particularly in the T1D group were able to further activate autologous CD4 + T cells, with increase in expression of CD69 and CD71. Finally, in a transwell assay, the stimulated pDCs and monocytes induced an increase in apoptosis of 1.1B4 beta cells. Additionally, we observed reduced expression of indoleamine 2,3-dioxygenase 1 (IDO1) in pDCs and monocytes of T1D subjects. Our results suggest that DNA-LL37 complexes activate pDCs and monocytes towards a proinflammatory phenotype during pathogenesis of T1D.

OX40 Regulates Both Innate and Adaptive Immunity and Promotes Nonalcoholic Steatohepatitis

Both innate and adaptive immune cells are involved in the pathogenesis of nonalcoholic steatohepatitis (NASH), but the crosstalk between innate and adaptive immunity is largely unknown. Here we show that compared with WT mice, OX40-/- mice exhibit decreased liver fat accumulation, lobular inflammation, and focal necrosis after feeding with diets that induce NASH. Mechanistically, OX40 deficiency suppresses Th1 and Th17 differentiation, and OX40 deficiency in Tcells inhibits monocyte migration, antigen presentation, and M1 polarization. Soluble OX40 stimulation alone upregulates antigen presentation, chemokine receptor expression, and proinflammatory cytokine secretion by liver monocytes. Furthermore, plasma soluble OX40 levels are positively associated with NASH in humans, suggesting clinical relevance of the findings. In conclusion, we show a mechanism for Tcell regulation of innate immune cells. OX40 is a key regulator of both intrahepatic innate and adaptive immunity, generates two-way signals, and promotes both proinflammatory monocyte and macrophage and Tcell function, resulting in NASH development.

Reactivity toward Bifidobacterium longum and Enterococcus hirae demonstrate robust CD8+ T cell response and better prognosis in HBV-related hepatocellular carcinoma

Recent studies suggest that several bacterial species are involved in tumor immunosurveillance and antitumor immunity. The role of bacteria in immune responses in HBV-related hepatocellular carcinoma (HCC) patients is still unknown. In this study, we examined the bacteria-reactive CD8+ T cell response in patients with HBV-related HCC. We found that circulating CD8+ T cells from healthy individuals demonstrated minimal or zero specificity toward a series of commensals and bacteria previously associated with antitumor effects, including Escherichia coli, Enterococcus faecium, Bifidobacterium longum, Bacteroides fragilis, and Enterococcus hirae. In contrast, the circulating CD8+ T cells from HBV-related HCC patients presented significantly elevated bacteria-reactive responses, albeit with high variations among different HCC individuals. Reactivity toward bacteria was also identified in tumor-infiltrating CD8+ T cells. These bacteria-reactive responses were not primarily induced by TLR ligand, but were dependent on the presence of antigen-presenting monocytes, and were MHC class I-restricted. Interestingly, we observed that the CD8+ T cell-to-Foxp3+ regulatory T cell ratio was positively correlated with the proportions of Bifidobacterium longum-reactive and Enterococcus hirae-reactive CD8+ T cells, while the frequency of PD-1+ CD8+ T cells was negatively correlated with the frequency of Enterococcus hirae-reactive CD8+ T cells. Furthermore, the disease-free survival time of HCC patients after tumor resection was positively correlated with the frequencies of Bifidobacterium longum-reactive and Enterococcus hirae-reactive CD8+ T cells. Together, these results suggested that certain bacterial species might present valuable antitumor effects.

A novel in vitro model reveals distinctive modulatory roles of Plasmodium falciparum and Plasmodium vivax on na\xefve cell-mediated immunity

BackgroundTo date, human peripheral blood mononuclear cells (PBMCs) have been used mainly in immune stimulation assays and the interpretation of data can be influenced by the previous immunological history of donors and cross reactivity with other infectious agents. Resolving these limitations requires an alternative in vitro model to uncover the primary response profiles.MethodsA novel in vitro model of mononuclear cells (MNCs) generated from haematopoietic stem cells (HSCs) was developed and these cells were then co-cultured with various antigens from Plasmodium falciparum and Plasmodium vivax to investigate the response of naïve immune cells to malaria antigens by flow cytometry.ResultsIn vitro stimulation of naïve lymphocytes showed that CD4+ and CD8+ T lymphocytes were significantly reduced (P < 0.01) by exposure to lysates of infected erythrocytes or intact erythrocytes infected with P. falciparum. The depletion was associated with the expression of CD95 (Fas receptor) on the surface of T lymphocytes. Maturation of T lymphocytes was affected differently, showing elevated CD3+CD4+CD8+ and CD3+CD4−CD8− T lymphocytes after stimulation with cell lysates of P. falciparum and P. vivax, respectively. In addition, antigen presenting monocytes and dendritic cells derived from haematopoietic stem cells showed impaired HLA-DR expression as a consequence of exposure to different species of malaria parasites.ConclusionThese results suggest that naïve mononuclear cells differentiated in vitro from HSCs could provide a valid model for the assessment of immunity. P. falciparum and P. vivax malaria parasites could modulate various populations of immune cells starting from newly differentiated mononuclear cells.

Coordinated immune activation by distinct mononuclear phagocytes subtypes against the mismatch of minor antigens

Abstract Recently, we identified that Batf3-dependent DCs were solely responsible for the rejection of minor antigen-mismatched grafts, and demonstrated in Batf3−/− female mice, lacking Batf3-dependent DCs, the complete acceptance of minor antigen-mismatched male cells, which are normally rejected in WT female mice. Intriguingly, this rejection occurs in the absence of PAMPs, leading to considerable uncertainty of how endogenous APC subtypes become activated and licensed to induce an adaptive immune response against male cells in female mice. Investigating this gap in knowledge is the main goal of this study. Rejection of minor antigen-mismatched grafts involves all branches of the immune system: adaptive immunity (T cells), humoral immunity (B cells) and innate immunity (DCs and antigen-presenting monocytes). Although we showed that depletion of one cell type dampens or omits the inflammatory outcome of minor antigen-mismatched graft rejection, here we show how lymphoid and myeloid cell subtypes act sequentially and in concert for the induction of minor antigen-mismatched graft rejection without the presence of PAMPs. In conclusion, we believe that understanding the mechanisms of action against minor antigen-mismatched graft rejection will also apply more broadly to other diseases such as autoimmunity and cancer, in which an immune response is elicited against self-associated minor antigens.

Ex vivo virotherapy with myxoma virus does not impair hematopoietic stem and progenitor cells

BackgroundRelapsing disease is a major challenge after hematopoietic cell transplantation for hematological malignancies. Myxoma virus (MYXV) is an oncolytic virus that can target and eliminate contaminating cancer cells from auto-transplant grafts. The aims of this study were to examine the impact of MYXV on normal hematopoietic stem and progenitor cells and define the optimal treatment conditions for ex vivo virotherapy. MethodsBone marrow (BM) and mobilized peripheral blood stem cells (mPBSCs) from patients with hematologic malignancies were treated with MYXV at various time, temperature and incubation media conditions. Treated BM cells from healthy normal donors were evaluated using flow cytometry for MYXV infection, long-term culture-initiating cell (LTC-IC) assay and colony-forming cell (CFC) assay. ResultsMYXV initiated infection in up to 45% of antigen-presenting monocytes, B cells and natural killer cells; however, these infections were uniformly aborted in >95% of all cells. Fresh graft sources showed higher levels of MYXV infection initiation than cryopreserved specimens, but in all cases less than 10% of CD34+ cells could be infected after ex vivo MYXV treatment. MYXV did not impair LTC-IC colony numbers compared with mock treatment. CFC colony types and numbers were also not impaired by MYXV treatment. MYXV incubation time, temperature or culture media did not significantly change the percentage of infected cells, LTC-IC colony formation or CFC colony formation. ConclusionsHuman hematopoietic cells are non-permissive for MYXV. Human hematopoietic stem and progenitor cells were not infected and thus unaffected by MYXV ex vivo treatment.

History and perspectives of the monocyte-macrophage system

The macrophage cell system was identified by Metchnikoff on the basis of its phagocytic ability. Later on, the reticulohistiocytic system was defined as being composed of antigen-presenting reticulum cells and macrophages. Van Furth proposed that the mononuclear phagocyte system includes all tissue macrophages as well as antigen-presenting cells and blood monocytes as their precursors. Recent findings have shown that blood monocytes are not just transient forms involved in the recruitment of macrophages but that different dendritic and monocytic subpopulations can be observed in blood. In tissue, self-renewing macrophages derived from the yolk sac as well as monocyte-derived dendritic cells and monocyte-derived macrophages can be distinguished. Due to their plasticity and polarization, under inflammatory conditions monocyte-derived macrophages may be beneficial for the reestablishment of homeostasis or may contribute to mostly chronic diseases. Because of their ubiquitous distribution, monocytes and macrophages are increasingly considered to be possible therapeutic targets.

Immune cells and cardiovascular health in premenopausal women of rural India chronically exposed to biomass smoke during daily household cooking

Changes in cells of the immune system are important indicators of systemic response of the body to air pollution. The aim of this study was to investigate the immunological changes in rural women who have been cooking exclusively with biomass for the past 5years or more and compare the findings with women cooking exclusively with liquefied petroleum gas (LPG). We conducted a cross-sectional analysis of the associations between indices of indoor air pollution (IAP) and a set of immune assays. Biomass users illustrated marked suppression in the total number of T-helper (CD4+) cells and B (CD19+) cells while appreciable rise was documented in the number of CD8+ T-cytotoxic cells and CD16+CD56+ natural killer (NK) cells. A consistent finding among biomass users was rise in regulatory T (Treg) cells. Among biomass users, peripheral lymphocyte subpopulations, Treg cells, and the number of typical monocytes (CD16−CD64+ cells), antigen presenting types (CD16+CD64− cells) and plasmacytoid cells (CD16−CD64− cells) were found to be significantly altered in those who daily cooked with dung in comparison to wood and crop residue users (p<0.05). Biomass users who cooked in kitchens adjacent to their living areas had significant changes in peripheral lymphocyte subpopulations, typical monocytes (CD16−CD64+) with high phagocytic activity and antigen presenting monocytes (CD16+CD64−) against women who cooked in separate kitchens (p<0.01). This study has shown that women who cooked exclusively with biomass fuel had alterations in immune defense compared with their neighbors who cooked with LPG.

Cecal Ligation Puncture Procedure

Human sepsis is characterized by a set of systemic reactions in response to intensive and massive infection that failed to be locally contained by the host. Currently, sepsis ranks among the top ten causes of mortality in the USA intensive care units. During sepsis there are two established haemodynamic phases that may overlap. The initial phase (hyperdynamic) is defined as a massive production of proinflammatory cytokines and reactive oxygen species by macrophages and neutrophils that affects vascular permeability (leading to hypotension), cardiac function and induces metabolic changes culminating in tissue necrosis and organ failure. Consequently, the most common cause of mortality is acute kidney injury. The second phase (hypodynamic) is an anti-inflammatory process involving altered monocyte antigen presentation, decreased lymphocyte proliferation and function and increased apoptosis. This state known as immunosuppression or immune depression sharply increases the risk of nocosomial infections and ultimately, death. The mechanisms of these pathophysiological processes are not well characterized. Because both phases of sepsis may cause irreversible and irreparable damage, it is essential to determine the immunological and physiological status of the patient. This is the main reason why many therapeutic drugs have failed. The same drug given at different stages of sepsis may be therapeutic or otherwise harmful or have no effect. To understand sepsis at various levels it is crucial to have a suitable and comprehensive animal model that reproduces the clinical course of the disease. It is important to characterize the pathophysiological mechanisms occurring during sepsis and control the model conditions for testing potential therapeutic agents. To study the etiology of human sepsis researchers have developed different animal models. The most widely used clinical model is cecal ligation and puncture (CLP). The CLP model consists of the perforation of the cecum allowing the release of fecal material into the peritoneal cavity to generate an exacerbated immune response induced by polymicrobial infection. This model fulfills the human condition that is clinically relevant. As in humans, mice that undergo CLP with fluid resuscitation show the first (early) hyperdynamic phase that in time progresses to the second (late) hypodynamic phase. In addition, the cytokine profile is similar to that seen in human sepsis where there is increased lymphocyte apoptosis (reviewed in). Due to the multiple and overlapping mechanisms involved in sepsis, researchers need a suitable sepsis model of controlled severity in order to obtain consistent and reproducible results.

Cecal Ligation Puncture Procedure

Human sepsis is characterized by a set of systemic reactions in response to intensive and massive infection that failed to be locally contained by the host. Currently, sepsis ranks among the top ten causes of mortality in the USA intensive care units 1. During sepsis there are two established haemodynamic phases that may overlap. The initial phase (hyperdynamic) is defined as a massive production of proinflammatory cytokines and reactive oxygen species by macrophages and neutrophils that affects vascular permeability (leading to hypotension), cardiac function and induces metabolic changes culminating in tissue necrosis and organ failure. Consequently, the most common cause of mortality is acute kidney injury. The second phase (hypodynamic) is an anti-inflammatory process involving altered monocyte antigen presentation, decreased lymphocyte proliferation and function and increased apoptosis. This state known as immunosuppression or immune depression sharply increases the risk of nocosomial infections and ultimately, death. The mechanisms of these pathophysiological processes are not well characterized. Because both phases of sepsis may cause irreversible and irreparable damage, it is essential to determine the immunological and physiological status of the patient. This is the main reason why many therapeutic drugs have failed. The same drug given at different stages of sepsis may be therapeutic or otherwise harmful or have no effect 2,3. To understand sepsis at various levels it is crucial to have a suitable and comprehensive animal model that reproduces the clinical course of the disease. It is important to characterize the pathophysiological mechanisms occurring during sepsis and control the model conditions for testing potential therapeutic agents. To study the etiology of human sepsis researchers have developed different animal models. The most widely used clinical model is cecal ligation and puncture (CLP). The CLP model consists of the perforation of the cecum allowing the release of fecal material into the peritoneal cavity to generate an exacerbated immune response induced by polymicrobial infection. This model fulfills the human condition that is clinically relevant. As in humans, mice that undergo CLP with fluid resuscitation show the first (early) hyperdynamic phase that in time progresses to the second (late) hypodynamic phase. In addition, the cytokine profile is similar to that seen in human sepsis where there is increased lymphocyte apoptosis (reviewed in 4,5). Due to the multiple and overlapping mechanisms involved in sepsis, researchers need a suitable sepsis model of controlled severity in order to obtain consistent and reproducible results.

Severity of the compensatory anti-inflammatory response determined by monocyte HLA-DR expression may assist outcome prediction in cirrhosis

To investigate variations in expression of the monocyte antigen presentation molecule HLA-DR in cirrhosis. HLA-DR expression was measured by flow cytometry in 100 patients within 48 h of admission and repeated a week later in 21 patients admitted to ICU. IL-10, TNF-α and IFN-γ secretion in response to lipopolysaccharide and recall antigens were measured by enzyme-linked immunosorbent spot (ELISPOT) assay in 12 patients (7 with clinical immunoparesis, 5 stable). HLA-DR level was 71% in stable patients, 53% with single organ dysfunction and 34% with multiple organ failure (p < 0.02). Within these groups, no significant differences in admission HLA-DR were seen between survivors and non-survivors. HLA-DR expression less than 40% predicted 90-day mortality with a specificity of 80% and sensitivity of 59% [area under the receiver operator curve (AUROC) 0.76]. HLA-DR less than 40% was an independent predictor of prognosis in multivariate analysis with a relative risk of 2.35 (p = 0.04), although sequential organ failure assessment score (SOFA) score displaced HLA-DR when included. In those admitted to intensive care failure to increase HLA-DR expression was predictive of death within 30 days (risk ratio 6.9, p = 0.007). Follow-up values predicted outcome with similar accuracy to acute physiology and chronic health evaluation II (APACHE II)/SOFA scores (AUROC 0.88). Response to endotoxin and recall antigen was characterised by an anti-inflammatory cytokine secretion profile, and was associated with impairment in recall antigen presentation capacity. HLA-DR expression less than 40% and a failure of recovery predict poor outcome in decompensated cirrhosis, but overall prognostic power remains inferior to conventional markers. Ex vivo experiments demonstrate reduced Th1 response to antigenic stimulation and an exaggerated counter-inflammatory cytokine secretion profile.

Hypothermia and Surgery

To examine cellular and immunologic mechanisms by which intraoperative hypothermia affects surgical patients. Avoidance of perioperative hypothermia has recently become a focus of attention as an important quality performance measure, aimed at optimizing the care of surgical patients. Anesthetized surgical patients are particularly at risk for hypothermia, which has been directly linked to the development of sequelae, such as coagulopathy, infection, morbid myocardial events, and death after surgery. However, many of the underlying immunologic mechanisms remain unclear. Venous blood samples from healthy volunteers were exposed for up to 4 hours to various temperatures following the addition of a 1 ng/mL lipopolysaccharide challenge. Innate immune function, assessed by the ability of monocytes to present antigen and coordinate cytokine release, was determined by qualitative and quantitative measurements of HLA-DR surface expression 2 hours following incubation, and proinflammatory tumor necrosis factor-alpha (TNF-alpha) and anti-inflammatory (IL-10) cytokine release in the first 4 hours. Monocyte incubation at hypothermic temperatures (34 degrees C) reduced HLA-DR surface expression, delayed TNF-alpha clearance, and increased IL-10 release. Conversely, hyperthermia (40 degrees C) increased monocyte antigen presentation and resulted in rapid decay of TNF-alpha. However, IL-10 release was also increased. Normothermia (37 degrees C) attenuated IL-10 release following the initial proinflammatory surge. Hypothermia exerts multiple effects at the cellular level, which impair innate immune function, and are associated with increased septic complications and mortality. These findings provide a physiological basis for perioperative temperature monitoring, which is a valid surgical performance measure that can be used to reduce surgical complications associated with avoidable hypothermia.