A Multi-Institutional Validation of the Prognostic Value of the Neutrophil-to-Lymphocyte Ratio in Patients With Diffuse Large B-Cell Lymphoma: A Study From The Latin American Group of Lymphoproliferative Disorders (GELL).

Introduction: We aimed at investigating the prognostic role of the neutrophil-to-lymphocyte ratio (NLR) in 2 independent cohorts of Latin American patients with diffuse large B-cell lymphoma (DLBCL) treated with chemoimmunotherapy.

Patients And Methods: The learning cohort was composed of 274 patients and the validation cohort of 323 patients, for a total of 597 patients. An optimal NLR cutoff ≥ 4 was determined using receiver operating characteristic analysis.

Thioperamide induces CD4 CD25 Foxp3 regulatory T lymphocytes in the lung mucosa of allergic mice through its action on dendritic cells.

Background: Histamine is an important mediator in the development of allergic reactions. The biological effects of histamine are mediated through four histaminergic receptors. In recent years, an important role has been assigned to the proinflammatory functions of histamine regarding the H4 receptor.

Impaired function of dendritic cells deficient in angiotensin II type 1 receptors.

Dendritic cells (DC) are highly specialized antigen-presenting cells with a unique ability to activate resting T lymphocytes and initiate primary immune responses. Angiotensin II (AII) is involved in key events of the inflammatory response. Because our previous work implicated an effect of AII on differentiation and function of murine and human DC, we investigated the impact of AII type 1 receptor (AT(1)) deficiency on the phenotypical and functional properties of mouse DC in vitro and in vivo.

Histamine-treated dendritic cells improve recruitment of type 2 CD8 T cells in the lungs of allergic mice.

Histamine controls the function of dendritic cells (DCs). It appears to be required for the normal development of DCs. It also induces the chemotaxis of immature DCs and promotes the differentiation of CD4(+) T cells into cells with a T helper type 2 (Th2) profile.

Regulation of neutrophil apoptosis by cytokines, pathogens and environmental stressors.

As a key component of the innate immune response, neutrophils play a major role in host protection against bacterial and fungi infections. Neutrophils are short-lived phagocytic cells and, as a first line of defense against host insult, they are rapidly and massively recruited from the circulation into inflammatory sites, where the expression of their apoptotic program can be regulated by a number of agents such as cytokines, pathogens and environmental stressors. Apoptosis of neutrophils is central to homoeostasis and the resolution of inflammation.

Histamine improves antigen uptake and cross-presentation by dendritic cells.

Previous studies have shown that histamine is able to modulate the function of dendritic cells (DCs). Histamine seems to be required for the normal differentiation of DCs. Moreover, it is capable of stimulating the chemotaxis of immature DCs and of promoting the differentiation of T CD4+ cells into a Th2 profile.

Extracellular acidosis triggers the maturation of human dendritic cells and the production of IL-12.

Although the development of an acidic tissue environment or acidosis is a hallmark of inflammatory processes, few studies analyze the effect of extracellular pH on immune cells. We have previously shown that exposure of murine dendritic cells (DCs) to pH 6.5 stimulates macropinocytosis and cross-presentation of extracellular Ags by MHC class I molecules.

Immune complexes inhibit differentiation, maturation, and function of human monocyte-derived dendritic cells.

The interaction between immune complexes (IC) and the receptors for the Fc portion of IgG (FcgammaRs) triggers regulatory and effector functions in the immune system. In this study, we investigated the effects of IC on differentiation, maturation, and functions of human monocyte-derived dendritic cells (DC). When IC were added on day 0, DC generated on day 6 (IC-DC) showed lower levels of CD1a and increased expression of CD14, MHC class II, and the macrophage marker CD68, as compared with normally differentiated DC.

Extracellular acidosis induces neutrophil activation by a mechanism dependent on activation of phosphatidylinositol 3-kinase/Akt and ERK pathways.

Inflammation in peripheral tissues is usually associated with the development of local acidosis; however, there are few studies aimed at analyzing the influence of acidosis on immune cells. We have shown previously that extracellular acidosis triggers human neutrophil activation, inducing a transient increase in intracellular Ca2+ concentration, a shape change response, the up-regulation of CD18 expression, and a delay of apoptosis. In this study, we analyzed the signaling pathways responsible for neutrophil activation.

The impact of extracellular acidosis on dendritic cell function.

Dendritic cells (DCs) are the most efficient antigen-presenting cells. They are activated in the periphery by conserved pathogen molecules and by inflammatory mediators produced by a variety of cell types in response to danger signals. It is widely appreciated that inflammatory responses in peripheral tissues are usually associated with the development of acidic microenvironments.

Analysis of the mechanisms involved in the stimulation of neutrophil apoptosis by tumour necrosis factor-alpha.

We have previously reported that human neutrophils pretreated with tumour necrosis factor-alpha (TNF-alpha) and then exposed to a variety of agents such as immune complexes, zymosan, phorbol 12-myristate 13-acetate (PMA), C5a, fMLP, or granulocyte-macrophage colony-stimulating factor (GM-CSF), undergo a dramatic stimulation of apoptosis, suggesting that TNF-alpha is able to prime an apoptotic death programme which can be rapidly triggered by different stimuli. We report here that this response involves the participation of Mac-1 (CD11b/CD18), is dependent on caspases 3, 8 and 9, and is associated with both a loss of mitochondrial transmembrane potential and a down-regulation in expression of the anti-apoptotic protein, Mcl-1. Interestingly, we also found that the anti-apoptotic cytokine interleukin-1 (IL-1) improves the ability of TNF-alpha to promote apoptosis, supporting the notion than TNF-alpha, acting together with IL-1, may favour the depletion of neutrophils from the inflammatory areas during the course of acute inflammation.

Acidosis improves uptake of antigens and MHC class I-restricted presentation by dendritic cells.

It is widely appreciated that inflammatory responses in peripheral tissues are usually associated to the development of acidic microenvironments. Despite this, there are few studies aimed to analyze the effect of extracellular pH on immune cell functions. We analyzed the impact of acidosis on the behavior of dendritic cells (DCs) derived from murine bone marrow.

Bacterial DNA activates human neutrophils by a CpG-independent pathway.

Bacterial DNA stimulates macrophages, monocytes, B lymphocytes, NK cells, and dendritic cells in a CpG-dependent manner. In this work we demonstrate that bacterial DNA, but not mammalian DNA, induces human neutrophil activation as assessed by L-selectin shedding, CD11b upregulation, and stimulation of cellular shape change, IL-8 secretion, and cell migration. Induction of these responses is not dependent on the presence of unmethylated CpG motifs, as neutrophil stimulatory properties were neither modified by CpG-methylation of bacterial DNA nor reproduced by oligonucleotides bearing CpG motifs.

Control of dendritic cell differentiation by angiotensin II.

Here we analyze the role of the angiotensinergic system in the differentiation of dendritic cells (DC). We found that human monocytes produce angiotensin II (AII) and express AT1 and AT2 receptors for AII. DC differentiated from human monocytes in the presence of AT1 receptor antagonists losartan or candesartan show very low levels of CD1a expression and poor endocytic and allostimulatory activities.

Stimulation of neutrophil apoptosis by immobilized IgA.

In the current study, we analyzed whether immunoglobulin A (IgA) is able to modulate neutrophil apoptosis. We found that culture of neutrophils on immobilized plasma IgA (iIgAp) or secretory IgA (iIgAs) induced a marked increase in apoptotic rates. By contrast, soluble IgAp, IgAs, or aggregated IgAp exerted no effect.

Nonpeptide antagonists of AT1 receptor for angiotensin II delay the onset of acute respiratory distress syndrome.

We have previously reported that losartan, a selective antagonist of AT1 receptors for angiotensin II (AII), strongly suppresses the activation of neutrophils by N-formylmethionyl-leucyl-phenylalanine (fMLP) through a mechanism that does not involve inhibition of AT1 receptors. Herein, we analyze whether losartan would prevent the development of the acute respiratory distress syndrome (ARDS) triggered by lung bacterial infection. We found that losartan (0.

Promotion of neutrophil apoptosis by TNF-alpha.

We examined the ability of TNF-alpha to modulate human neutrophil apoptosis. Neutrophils cultured with TNF-alpha alone undergo a low but significant increase in the number of apoptotic cells. More interestingly, when neutrophils were pretreated with TNF-alpha for 1-2 min at 37 degrees C and then were exposed to a variety of agents such as immobilized IgG, IgG-coated erythrocytes, complement-treated erythrocytes, zymosan, PMA, zymosan-activated serum, fMLP, Escherichia coli, and GM-CSF for 3 h at 37 degrees C, a marked stimulation of apoptosis was observed.

Losartan, a selective inhibitor of subtype AT1 receptors for angiotensin II, inhibits neutrophil recruitment in the lung triggered by fMLP.

We have shown that losartan, a selective inhibitor of AT1 receptors for angiotensin II (AII), inhibits the binding of [3H]fMLP to neutrophil receptors (FPR). Here, we analyze, in Wistar rats, the effect of losartan on neutrophil recruitment in the lung triggered by fMLP. We found that i.

Acidic pH increases the avidity of FcgammaR for immune complexes.

The interaction of immunoglobulin G (IgG) antibodies with FcgammaR constitutes a critical mechanism through which IgG antibody effector functions are mediated. In the current work we have examined whether human neutrophil FcgammaR exhibit pH dependence in their association with IgG. Binding assays were performed in culture medium adjusted to different pH values.

Extracellular acidification induces human neutrophil activation.

In the current work, we evaluated the effect of extracellular acidification on neutrophil physiology. Neutrophils suspended in bicarbonate-buffered RPMI 1640 medium adjusted to acidic pH values (pH 6.5-7.

Effect of nitric oxide donors on oxygen-dependent cytotoxic responses mediated by neutrophils.

We analyzed the effect of nitric oxide (NO) on oxygen-dependent cytotoxic responses mediated by neutrophils against unopsonized erythrocytes using three NO donors: S-nitrosoglutathione (GSNO), S-nitroso-N-acetylpenicillamine (SNAP), and sodium nitroprusside (SNP). Neutrophils were treated with these compounds for 1-2 min at 37 degrees C and cytotoxicity was then triggered in the presence of NO donors by precipitating immune complexes, aggregated IgG, the chemotactic peptide FMLP, or opsonized zymosan. GSNO induced, in all cases, a marked increase in cytotoxic responses, while SNAP moderately increased cytotoxicity triggered by immune complexes, aggregated IgG, or Z, opsonized zymosen, without modifying those responses induced by FMLP.

Modulation of human neutrophil apoptosis by immune complexes.

In the present study we examined whether immune complexes (IC) are able to modulate human neutrophil apoptosis. We observed different effects depending on the type of IC employed. Precipitating IC (pIC) and Ab-coated erythrocytes (E-IgG) triggered a marked stimulation of apoptosis, while heat-aggregated IgG and soluble IC, significantly delayed spontaneous apoptosis.

Inhibition of human neutrophil apoptosis by platelets.

In the absence of appropriate stimuli, polymorphonuclear neutrophils rapidly undergo characteristic changes indicative of programmed cell death or apoptosis. We report here that neutrophils cultured in the presence of platelets (neutrophil:platelet ratios of 1:50, 1:25, and 1:10) show a dramatic inhibition of apoptosis compared with neutrophils cultured alone. Similar degrees of apoptosis delay were induced by viable unstimulated platelets, fixed unstimulated platelets, or fixed activated (1 U/ml thrombin) platelets.

Neutrophil apoptosis induced by proteolytic enzymes.

In this study, we show that three proteolytic enzymes of different specificity-pronase, chymotrypsin, and trypsin-induced a dramatic stimulation of neutrophil apoptosis as shown by morphologic characteristics, analysis of cell DNA content, and presence of a characteristic "ladder" pattern of DNA fragmentation. The action of either chymotrypsin or trypsin was completely prevented by the serine protease inhibitor aprotinin, indicating that the proteolytic activity of the enzymes accounts for apoptosis induction. Stimulation of neutrophil apoptosis by proteases was observed in culture medium supplemented with either inactivated fetal calf serum (0.

Effect of nitric oxide donors on neutrophil responses induced by immune complexes.

The present study characterizes the effect of two nitric oxide (NO) donors, S-nitrosoglutathione (GSNO) and sodium nitroprusside (SNP), on the ability of neutrophils to perform different responses triggered by immune complexes (IC). Pretreatment of neutrophils with either GSNO or SNP exerted a biphasic action on antibody-dependent cellular cytotoxicity (ADCC) performed against erythrocytes (E) coated with IgG antibodies (IgG-E), depending on the amount of IgG employed. While with high amounts of antibodies ADCC was markedly inhibited, at low amounts of antibodies it was significantly increased.