Behçet's disease (BD) is a systemic vasculitis with unclear etiology and pathogenesis. Although several viral and bacterial causes have been investigated in detail for several years, of late it is widely accepted that microorganisms may play a role as a trigger, or as a cross-reactive antigens that interfere with self-antigens, ...

Human polymorphonuclear leukocytes (PMN) are a first line of defense against fungal infections. PMN express numerous pattern recognition receptors (PRR) that facilitate identification of invading microorganisms and ultimately promote resolution of disease. Dectin-1 (beta-glucan receptor) is a PRR expressed on several cell types and has been studied on monocytes and ...

Polymorphonuclear cells (PMNs) are essential for the innate immune response against invading bacteria. At the same time, modulation of PMNs' apoptosis or cell death by bacteria has emerged as a mechanism of pathogenesis. Wolbachia bacteria are Gram-negative endosymbionts of filarial nematodes and arthropods, phylogenetically related to the genera Anaplasma, Ehrlichia ...

Paracoccidioidomycosis, a deep mycosis endemic in Latin America, is a chronic granulomatous disease caused by the fungus Paracoccidioides brasiliensis. Phagocytic cells play a critical role against the fungus and several papers show the effects of activator and suppressive cytokines on macrophage and monocyte functions. However, the studies focusing on polymorphonuclear ...

Some cells, including neutrophils, accumulate high intracellular ascorbate concentrations, which suggests that they have an important function in these cells. In this study we have used L-gulono-gamma-lactone oxidase (Gulo)-/- mice, which are unable to synthesize ascorbate, to generate ascorbate-deficient neutrophils and have used these to investigate the effect of ascorbate ...

Lysosomal membrane permeabilization (LMP) is emerging as an important regulator of cell apoptosis. Human neutrophils are highly granulated phagocytes, which respond to pathogens by exhibiting increased production of reactive oxygen species (ROS) and lysosomal degranulation. In a previous study, we observed that intracellular, nonphagosomal generation of ROS triggered by adherent ...

BACKGROUND: Previously, we have demonstrated that surgical stress rapidly induced transient hyporesponsiveness of blood cells to endotoxin and that monocyte mCD14 and HLA-DR expression decreased soon after the start of surgery under general anaesthesia. This study was designed to investigate the effects of epidural anaesthesia on surgical stress-induced immunosuppression in ...

The recruitment and activation of neutrophils at infected tissues is essential for host defense against invading microorganisms. However, excessive neutrophil recruitment or activation can also damage the surrounding tissues and cause unwanted inflammation. Hence, the responsiveness of neutrophils needs to be tightly regulated. In this study, we have investigated the ...

To study the possible changes, neutrophils in 24 normal male Muslim adults were measured and compared before and after Ramadan, using chemiluminescence method. There were no significant effects of fasting on blood neutrophil function during Ramadan. Fasting during holy month of Ramadan does not change neutrophil functions and has no ...

The inhibition of neutrophil apoptosis plays a central role in human granulocytic anaplasmosis. Intracellular signaling pathways through which the obligatory intracellular bacterium Anaplasma phagocytophilum inhibits the spontaneous apoptosis of human peripheral blood neutrophils were investigated. In this paper, it was found that the decrease of bfl-1 mRNA expression and activation ...

Polymorphonuclear neutrophils are short-lived phagocytic cells that serve as cardinal early cellular effectors of innate immunity. Both oxidative and non-oxidative mechanisms contribute to microbial killing by the neutrophil. Neutrophil defence mechanisms are potent but non-specific, with the result that inadvertent injury to host tissues commonly accompanies the activation of a ...

Neutrophil-derived granule enzymes, oxidants, and mediators have been implicated in the pathogenesis of a variety of inflammatory diseases. Neutrophil apoptosis is associated with the loss of expression of adhesion molecules and greatly reduced responsiveness to external stimuli, so that these cells become functionally isolated from their environment. In contrast with ...

BACKGROUND: Previous studies suggest that rhythmic compression of the abdomen (abdominal lymphatic pump techniques, LPT) enhances immunity and resistance to infectious disease, but direct evidence of this has not been documented. In this study, the thoracic duct of eight anesthetized mongrel dogs was catheterized, so the immediate effects of LPT ...

Hypertonic sodium chloride (NaCl) solution has been shown to have beneficial effects on patients with hypovolemic shock. Therapy with hypertonic saline seems to neutralize or minimize the deleterious immune responses in these patients. In this study, we addressed how hypertonic NaCl solution affects the release of cytokines by isolated human ...

PURPOSE OF REVIEW: Neutrophils are an essential component of the innate immune response and a major contributor to inflammation. Consequently, neutrophil number in the blood is tightly regulated. Herein, we review recent studies that have greatly advanced our understanding of the mechanisms controlling neutrophil homeostasis. RECENT FINDINGS: Accumulating evidence shows ...

Interleukin (IL)-17 is a proinflammatory cytokine which induces differentiation and migration of neutrophils through induction of cytokines and chemokines including granulocyte-colony stimulating factor and CXCL8/IL-8. IL-17-producing CD4(+) T cells (Th17) have pivotal role in pathogenesis of autoimmune diseases. IL-17 is also involved in protective immunity against various infections. IL-17 has ...

Neutrophil (also known as polymorphonuclear leukocyte, or PMN) transepithelial migration and accumulation at mucosal surfaces is a hallmark of many inflammatory conditions. This process correlates directly with clinical disease activity and epithelial injury. Currently, the mechanisms that define PMN epithelial interactions during an inflammatory response are not completely understood. This ...

Reactive oxygen species formation or respiratory burst by the neutrophils helps to remove the invaded pathogens and thus constitute a major defense against pathogenic microorganisms. Production of these radicals by activated neutrophils at the site of inflammation however inflicts damage to the host tissue. Modulation of the neutrophil respiratory burst ...

In recent years, several studies have brought forward new and exciting discoveries in polymorphonuclear neutrophil research by establishing that the release of inflammatory cytokines constitutes a novel and important aspect of the biology of this cell. At present, neutrophils should no longer be regarded as cells that only release preformed ...

The crucial contribution of neutrophils to innate immunity extends well beyond their traditional role as professional phagocytes. Indeed, it is now well established that neutrophils generate a plethora of inflammatory cytokines and chemokines that are profoundly involved in the onset and evolution of the inflammatory reaction. Several recent studies have ...

Human neutrophils undergo autophagic-like cell death following Sialic acid binding immunoglobulin-like lectin-9 (Siglec-9) ligation and concurrent stimulation with certain, but not all, neutrophil survival cytokines. Caspase inhibition by these cytokines is required, but is not sufficient, to trigger this particular form of cell death. Additional mechanisms may involve reactive oxygen ...

BACKGROUND: Inflammation and nociceptive sensitization are hallmarks of tissue surrounding surgical incisions. Recent studies demonstrate that several cytokines may participate in the enhancement of nociception near these wounds. Since opioids like morphine interact with neutrophils and other immunocytes, it is possible that morphine exerts some of its antinociceptive action after ...

Chemoattractants induce neutrophil polarization through localized polymerization of F-actin at the leading edge. The suppression of rear and lateral protrusions is required for efficient chemotaxis and involves the temporal and spatial segregation of signaling molecules. We have previously shown that the intracellular calcium-dependent protease calpain is required for cell migration ...

To investigate the role of neutrophil apoptosis in the pathogenesis of chronic neutropenia, we examined constitutive and death receptor-mediated apoptosis ex vivo of peripheral blood neutrophils obtained from six chronic idiopathic neutropenia (CIN) patients and six healthy adult blood donors. Apoptosis was quantified based on phosphatidylserine externalization and caspase-3 activation ...

The contribution of the high abundance of inflammatory cells present in the human endometrium prior to and during menstruation is unknown with respect to endometrial repair and/or menstruation. In this study, the presence and localisation of markers for key inflammatory cells have been examined in a mouse model of endometrial ...

Candida albicans is a common cause of nosocomial infections whose virulence depends on the reversible switch from blastoconidia to hyphal forms. Neutrophils (or polymorphonuclear leukocytes (PMNs)) readily clear blastoconidia by phagocytosis, but filaments are too long to be ingested. Mechanisms regulating immune recognition and response to filamentous fungal pathogens are ...

Neutrophils are not simply scavenging phagocytes that clear extracellular spaces of rapidly proliferating microbes; they are also active in the control of infections by intracellular pathogens. Several mechanisms for nonphagocytic roles of neutrophils in protective immunity have been put forth over the years but further evidence has recently been accumulating ...

Neutrophils and monocytes play a central role in host defence. The invading leucocytes are capable of synthesizing and releasing a variety of proinflammatory mediators including cytokines. Given the importance of cytokines in the progression of chronic and acute inflammatory processes, we aimed to ascertain whether the release of interleukin (IL)-8, ...

The nucleosome is a major autoantigen in systemic lupus erythematosus (SLE); it can be detected as a circulating complex in the serum, and nucleosomes have been suggested to play a key role in disease development. In the present study, we show for the first time that physiological concentrations of purified ...

CD4+CD25+ T regulatory (Treg) cells play a central role in the suppression of immune response and prevention of autoimmune reactions. Pathogen recognition receptors expressed by immune cells, such as TLRs, may provide a critical link between the innate and adaptive immune systems. There is also evidence that TLR ligands can ...

Our previous studies demonstrated that i.p. injection of late apoptotic P388 cells caused phagocytosis by macrophages and transient infiltration of neutrophils into the peritoneal cavity. As neutrophils are known to function as effectors as well as regulators in the immune response, we examined the roles of infiltrating neutrophils in alloantigen-specific ...

Inflammation facilitates tumor progression including metastasis. Interleukin-8 (IL-8) is a chemokine that regulates polymorphonuclear neutrophil (PMN) mobilization and activity and we hypothesize that this cytokine influences tumor behavior. We have demonstrated that IL-8 is crucial for PMN-mediated melanoma extravasation under flow conditions. In addition, IL-8 is up-regulated in PMNs upon ...

In microbial infections polymorphnuclear neutrophils (PMN) constitute a major part of the innate host defence, based upon their ability to rapidly accumulate in inflamed tissues and clear the site of infection from microbial pathogens by their potent effector mechanisms. The recently described transmembrane receptor herpes virus entry mediator (HVEM) is ...

The role of neutrophils in the immune response has long been regarded as mainly phagocytic, but recent publications have indicated the production of several cytokines by polymorphonuclear leucocytes (PMN). The results of the individual reports, however, vary considerably. In this study, we established a cytokine profile of pure human neutrophils ...

Proteinase 3 (PR3) is found in granules of all neutrophils but also on the plasma membrane of a subset of neutrophils (mPR3). CD177, another neutrophil protein, also displays a bimodal surface expression. In this study, we have investigated the coexpression of these two molecules, as well as the effect of ...

We have previously shown that normal human peripheral blood polymorphonuclear neutrophils (PMNs) contain cytoplasmic 'stores' of three key molecules normally associated with antigen presentation and T-cell costimulation, i.e. major histocompatibility complex class II (DR) antigen, CD80 (B7-1) and CD86 (B7-2). These cytoplasmic molecules were found to translocate to the cell ...

Hepatic infiltration of polymorphonuclear leukocytes (neutrophils) is an early response to tissue injury, cellular stress or systemic inflammation. Neutrophil activation is vital for host-defense and the removal of cell debris but can also cause additional tissue damage or even liver failure. In order to prevent the detrimental effects of neutrophils ...

OBJECTIVE: To discuss the acute phase of inflammatory response with a focus on the neutrophilic response and its role in inflammation. We discuss the relative balance between the need for inflammation to stimulate repair and the need to limit inflammation because of the additional damage it causes. DATA SOURCES: We ...

It has been demonstrated that infections due to Shiga toxins (Stx) producing Escherichia coli are the main cause of the haemolytic uraemic syndrome (HUS). However, the contribution of the inflammatory response in the pathogenesis of the disease has also been well established. Neutrophils (PMN) represent a central component of inflammation ...

Diesel exhaust particles (DEP) are associated with respiratory disease and exposure to diesel exhaust induces an inflammatory response associated with marked leukocytic infiltration in the lung. This study examined whether neutrophils are activated by the active component of DEP (methanol extract of DEP [me-DEP]). The authors demonstrated that neutrophils exposed ...

The leukocyte activation marker CD69 functions as a negative regulator of the immune response, both in NK-dependent tumor rejection and in the inflammation associated with lymphocyte-dependent collagen-induced arthritis. In contrast, it has been reported that CD69-deficient mice are refractory to the neutrophil-dependent acute inflammatory response associated with anti-type II collagen ...

OBJECTIVE: Monosodium urate monohydrate (MSU) crystals have remarkable inflammatory potential. However, gouty inflammation is spontaneously self-limited, an occurrence recognized since antiquity. Gouty synovitis is driven and sustained by neutrophil influx. Importantly, macrophage phagocytosis of apoptotic (but not necrotic) neutrophils is antiinflammatory. Therefore, we tested the hypothesis that efficient clearance of ...

Delayed neutrophil apoptosis is characteristic of sepsis and may accentuate organ injury. It has been shown that PI-3K and MAPK pathways provide survival signaling in neutrophils. In this study, we demonstrate that neutrophils isolated from septic rats are resistant to apoptosis in comparison with the cells from normal animals. In ...

Neutrophils are critical in the inflammatory process by moving rapidly to tissue sites of inflammation. Members of the small Rho GTPase family, Rac1, Rac2, CDC42, and RhoA, are central regulators of cell migration by cytoskeleton rearrangement. The role of Rac1 in neutrophil migration related to inflammatory processes has remained elusive ...

Neutrophil spontaneous death plays essential roles in neutrophil homeostasis and resolution of inflammation, whereas the underlying molecular mechanisms are still ill-defined. Neutrophils die because of programmed cell death or apoptosis. However, treatment with inhibitor of caspases, which are responsible for the majority of apoptotic cell deaths, does not prevent the ...

Accumulating evidence support a role of neutrophils in coronary artery disease (CAD). However little is known about the action of neutrophils at a local inflammatory site represented by an atherosclerotic plaque. To gain insight into these issues, we applied a skin blister model that permits analyses of in vivo transmigrated ...

Neutrophil chemotaxis to sites of inflammation is a critical process during normal immune responses to tissue injury and infection and pathological immune responses leading to chronic inflammation. Although progress has been made in understanding the mechanisms that promote neutrophil recruitment to inflamed tissue, the mechanisms that regulate the resolution phase ...

Injured growth plate cartilage is often repaired by bony tissue, resulting in impaired bone growth in children. Previously, injury-induced, initial inflammatory response was shown to be an acute inflammatory event containing predominantly neutrophils. To examine potential roles of neutrophils in the bony repair, a neutrophil-neutralizing antiserum or control normal serum ...

The inflammatory response to tissue injury is a multi-faceted process. During this process, neutrophils migrate in the extravascular spaces, directed to the site of injury by chemical gradients generated by chemotactic molecules. S100A8, a protein associated with a wide variety of inflammatory conditions, is heavily over-expressed in association with inflammation. ...

Neutrophils play essential roles in several inflammatory reactions. Oxidant/antioxidant imbalance is thought to be partially involved in the pathogenesis of the disorders. Under the conditions of oxidative stress, superoxide dismutase (SOD) acts as an endogenous cellular defense system to degrade superoxide (O2-) into oxygen and hydrogen peroxide. Therefore, SOD is ...