Control Polymorphonuclear Neutrophils Research Articles

Neutrophil Extracellular Traps Generation Relates with Early Stage and Vascular Complications in Systemic Sclerosis.

Systemic sclerosis (SSc) is a systemic disease characterized by a great clinical and immunological heterogeneity whose pathophysiology is still being unraveled. Recently, innate immunity has been proposed to participate to the pathogenesis of SSc. In this study, we investigated the release of neutrophil extracellular traps (NETs) according to patient phenotype. Polymorphonuclear neutrophils (PMN) from 34 SSc patients and 26 healthy controls were stimulated by serum from SSc or healthy subject. NETs were visualized using epifluorescence microscope after DNA, myeloperoxidase, and Histone H3 tagging. Area of NETs were quantified using an original macro running in ImageJ® software. PMN from SSc patients were significantly more prone to releasing NETs than control PMN after autologous stimulation. PMN from patients with severe vascular complications (pulmonary arterial hypertension, digital ulcers) produced more NETs than PMN from other SSc patients and their aberrant NET production appeared to be sustained over time. In patients with pulmonary interstitial disease or extensive cutaneous fibrosis, NET production was high at an early stage of the disease before progressively decreasing. Both serum factors and PMN activation status were involved in the enhanced production of NETs in SSc. Consequently, neutrophils and especially NETosis represent new physiopathological and therapeutic fields in SSc.

Heat-shock protein-90 prolongs septic neutrophil survival by protecting c-Src kinase and caspase-8 from proteasomal degradation.

The brief lifespan of the polymorphonuclear neutrophil (PMN) is regulated through its capacity to undergo apoptosis, a constitutive process that is actively inhibited during sepsis. We sought to define the cellular mechanisms through which Heat Shock Protein 90 (Hsp90) prolongs the survival of inflammatory PMN. We evaluated Hsp90 expression and interaction with client proteins in PMNs from patients with sepsis and in healthy control PMNs treated with LPS (1μg/mL). Hsp90 activity was inhibited pharmacologically using radicicol (Rad; 1 μM), and Hsp90 transcription was silenced in septic PMN using siRNA. PMN apoptosis was evaluated by flow cytometry and expression of cleaved caspase-8 and -3. Septic PMNs showed reduced rates of apoptosis compared with control PMNs 21h after isolation, and Hsp90-α mRNA was significantly more abundant in septic PMN. Caspase-8 coimmunoprecipitated with Hsp90, c-Src, and the p85 inhibitory subunit of PI3K in both septic and LPS-treated PMN. Inhibition of Hsp90 activity with Rad or its translation using siRNA restored basal rates of apoptosis in both septic and LPS-treated PMN. Radicicol further reduced c-Src protein abundance, increased the ubiquitination of caspase-8 and c-Src, and enhanced the cleavage of caspase-8 and -3. We conclude that Hsp90 prolongs the survival of activated neutrophils by stabilizing a molecular complex of c-Src kinase and caspase-8, preventing their ubiquitination, and resulting in inhibition of the catalytic activity of caspase-8 and -3.

Expression of functional tissue factor by neutrophil extracellular traps in culprit artery of acute myocardial infarction.

Neutrophil extracellular traps (NETs) are chromatin filaments released by activated polymorphonuclear neutrophils (PMNs) and decorated with granule proteins with various properties. Several lines of evidence implicate NETs in thrombosis. The functional significance and the in vivo relevance of NETs during atherothrombosis in humans have not been addressed until now. Selective sampling of thrombotic material and surrounding blood from the infarct-related coronary artery (IRA) and the non-IRA was performed during primary percutaneous revascularization in 18 patients with ST-segment elevation acute myocardial infarction (STEMI). Thrombi isolated from IRA contained PMNs and NETs decorated with tissue factor (TF). Although TF was expressed intracellularly in circulating PMNs of STEMI patients, active TF was specifically exposed by NETs obtained from the site of plaque rupture. Treatment of NET structures with DNase I abolished TF functionality measurement. In vitro treatment of control PMNs with plasma obtained from IRA and non-IRA was further shown to induce intracellular up-regulation of TF but not NET formation. A second step consisting of the interaction between PMNs and thrombin-activated platelets was required for NET generation and subsequent TF exposure. The interaction of thrombin-activated platelets with PMNs at the site of plaque rupture during acute STEMI results in local NET formation and delivery of active TF. The notion that NETs represent a mechanism by which PMNs release thrombogenic signals during atherothrombosis may offer novel therapeutic targets.

Increase in interleukin-8 production from circulating neutrophils upon antibiotic therapy in cystic fibrosis patients

BackgroundIt is not known whether antibiotic therapy for lung disease in cystic fibrosis (CF) has an influence on circulating polymorphonuclear neutrophil (PMN) function and apoptosis. Patients and methodsBlood PMNs were obtained from 14 CF patients before and after antibiotic treatment for an acute exacerbation, and from 10 healthy controls. PMNs were evaluated for production of reactive oxygen species (ROS) by spectrophotometry, of cytokines in the conditioned medium by ELISA, and apoptotic response by cytofluorimetry. ResultsROS and interleukin (IL)-8 were produced at higher levels by CF PMNs pre-therapy than control PMNs under basal conditions. IL-8 levels further increased after therapy. Early apoptotic response was higher in CF PMNs pre-therapy than in control PMNs, and this pattern did not change after antibiotic treatment. ConclusionsCirculating PMNs are primed in CF acute patients. Further studies are needed to consider PMN-produced IL-8 as a biomarker to evaluate response to antibiotic therapy in CF patients.

Apoptosis and Bax, Bcl-2, Mcl-1 expression in neutrophils of Crohnʼs disease patients

The etiology of Crohn's disease (CD) remains unknown, and the defective function of neutrophils appears to be associated with this pathology. Neutrophils undergo spontaneous apoptosis which, if not tightly regulated, can induce the development of chronic inflammatory disease. The Bcl-2 protein family is also involved in the regulation of neutrophil apoptosis. This study investigated the apoptosis and expression of some regulatory factors in CD patient and control polymorphonuclear neutrophils (PMN) in suspension and in adhesion on fibronectin, an extracellular matrix protein. These 2 conditions mimic circulating neutrophils before they are recruited at the intestinal levels, and their adhesion to tissue. Apoptosis in CD patient PMN was delayed in suspension and accelerated in adhesion, which is the opposite of what happens in controls. Higher levels of Bax, Bcl-2, and Mcl-1 proteins were registered in freshly isolated CD patient PMN, in contrast to controls, in which Bcl-2 protein was undetectable. Among the studied pro- and antiapoptotic factors, Bax levels seem to be mainly related to the difference in apoptosis between PMN of CD patients and controls. For the first time it has been demonstrated by direct experimental evidence that apoptosis in CD patient PMN is regulated differently from that of control PMN. Abnormal expression of regulating apoptosis proteins is shown in CD patient PMN. These data suggest that the defective functionality of neutrophils can be the early event responsible for the altered mucosal immune response in CD, and that neutrophil apoptosis may offer a new target for specific drugs and therapy tools.

Effect of acetate-free biofiltration and bicarbonate hemodialysis on neutrophil activation

Background: Activation of polymorphonuclear neutrophils (PMNs) and monocytes has been described during hemodialysis (HD), which results in the release of reactive oxygen species and cytokines. Acetate-free biofiltration (AFB) has been shown to cause less monocyte activation and cytokine release than bicarbonate HD (BHD). No data are available to date on the effect of AFB on PMN activation. Methods: We studied ex vivo superoxide anion release by PMNs isolated from nine patients treated in random order with AFB or BHD (three sessions each). Plasma interleukin-1β (IL-1β) levels and the nitric oxide (NO) synthetic pathway also were evaluated. A polyacrylonitrile (AN69; Hospal, Bologna, Italy) dialyzer was used for both treatments. Fourteen healthy volunteers were used as controls. Blood samples were drawn predialysis and 5 and 15 minutes after starting dialysis to obtain plasma and PMNs. Results: Neither ex vivo superoxide anion release nor blood PMN count was affected by AFB. Conversely, a peak in superoxide anion production associated with a decrease in PMN count was observed at 5 minutes during BHD. Results of superoxide anion production by control PMNs exposed in vitro to AFB or bicarbonate dialysis bath or Hank's balanced salt solution supplemented with bicarbonate or acetate indicated that BHD-induced PMN activation could be attributed to the amount of bicarbonate present in the dialysis bath. IL-1β plasma levels did not change during dialysis with AFB and were numerically higher at 5 and 15 minutes with respect to predialysis values during BHD. Uremic plasma obtained during either AFB or BHD induced greater NO synthesis by human umbilical vein endothelial cells than control plasma. Conclusion: AFB, unlike BHD, does not cause PMN and monocyte activation, which could have a positive impact on dialysis-associated cardiovascular disease of dialyzed patients. © 2002 by the National Kidney Foundation, Inc.

Effects of endotoxin on neutrophil-mediated I/R injury in isolated perfused rat hearts.

With the use of a syngeneic model, we demonstrate that rat polymorphonuclear neutrophils (PMNs) exacerbate ischemia-reperfusion injury in the isolated rat heart. However, PMNs (19 x 10(6) cells) from lipopolysaccharide (LPS)-treated rats (LPS-PMNs; 100 mg/kg administered 7 h before exsanguination) induce less reperfusion injury in the isolated heart. Average recovery of left ventricular developed pressure after 20 min of ischemia and 60 min of reperfusion was 51 +/- 4% in hearts receiving PMNs from saline-treated control rats (saline-PMNs) versus 78 +/- 2% in hearts receiving LPS-PMNs. Ischemic hearts reperfused with LPS-PMNs recovered to the same extent as did hearts reperfused with Krebs buffer only. LPS-PMNs and saline-PMNs showed no difference in basal or phorbol ester-induced superoxide production. Whereas twice the number of LPS-PMNs was positive for nitroblue tetrazolium, the percent positive for L-selectin, a receptor integral in PMN-adhesion to endothelium, was 50% less in LPS-PMNs than in controls. After reperfusion, three-fourths of the saline-PMNs remained within the hearts, whereas only one-fourth of LPS-PMNs were trapped. These data suggest that PMNs from LPS-treated rats do not exacerbate ischemia-reperfusion injury as do control PMNs, possibly, due to impaired PMN adhesion to endothelium as a result of decreased L-selectin receptors.

Time-dependent loss of Mac-1 from infiltrating neutrophils in the reperfused myocardium.

Numerous studies have shown that polymorphonuclear neutrophils (PMNs) infiltrate the myocardium immediately after reperfusion of infarcted tissue. Studies with mAbs in vivo and cellular studies in vitro suggest that PMN-induced injury of the cardiac myocyte involve Mac-1 adhesion to myocyte ICAM-1. In this study we demonstrate that PMNs that have infiltrated the ischemic area begin to lose Mac-1 within the first 3 h. By the fifth hour of reperfusion, minimal CD11b staining is seen on PMNs using immunostaining, whereas CD11a remained unchanged. Immunoreactivity of postreperfusion cardiac lymph with R15.7 (anti-CD18) or MY904 (anti-CD11b) was positive in all animals but not for CD11a (R7.1), indicating a specific loss of Mac-1. Immunoprecipitation with either R15.7 or MY904 resulted in identical peptides (a doublet at 190 kDa and a band at 80 kDa), suggesting that both alpha and beta subunits of Mac-1 heterodimer were released. Immunoprecipitation of control PMN lysates revealed bands of 198 kDa and 91 kDa slightly greater than those from the released Mac-1. An in vitro model of homotypic aggregation showed a similar loss of Mac-1 from PMNs; immunoprecipitates of the supernatant demonstrated peptide bands identical with those found in postischemic cardiac lymph. The appearance of soluble Mac-1 in vitro was prevented by anti-CD18 mAb, R15.7, and also by protease inhibition by PMSF. Thus, in vivo and in vitro, activated PMNs lose Mac-1 in a process that may be dependent upon adhesion and subsequent proteolysis.

Polytrauma induces increased expression of pyruvate kinase in neutrophils

Polytrauma (PT) leads to systemic activation of polymorphonuclear neutrophils (PMNs). Organ damage commonly found in these patients is ascribed to respiratory bursts of activated PMNs. With the use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, PMN extracts from PT patients were found to contain a clear protein band not seen in control PMNs from healthy volunteers. This band was identified by amino acid sequencing and Western blotting as pyruvate kinase (PK). Enzymatic assays revealed a 600-fold increase in PK activity in PMNs of PT patients, with the highest levels occurring between the fifth and seventh posttraumatic day. In lymphocytes, no such increase was detectable. As PK is a major regulatory enzyme in glycolysis, glucose-dependent lactate production in PMNs from PT patients was assayed. These cells showed a higher glycolytic lactate production than controls. It was additionally demonstrated that acute activation of respiratory burst activity depends mainly on breakdown of glucose to lactate via the pentose-phosphate pathway and glycolysis. In PMNs from PT patients, this glucose-dependent respiratory burst activity was more than twofold higher than in controls. The increase in expression and activity of PK in PMNs from PT patients may contribute to the high glucose-dependent respiratory burst activity seen in these cells.

Impaired granulocyte formylpeptide-induced superoxide generation in chronically ill, malnourished, elderly patients.

Protein-energy malnutrition (PEM), often occurring in patients with chronic disease, is associated with a decreased capacity to combat infections. In this study we assessed polymorphonuclear neutrophil (PMN) superoxide anion (*O2-) formation in elderly PEM patients with various chronic diseases. Nineteen patients (75+/-1 years), with body mass index 17.1+/-0.4, and 19 age-matched healthy controls were included. Fourteen patients and 14 controls were re-examined in a 3 month follow-up. A service of internal medicine at a university-affiliated hospital. Eight patients were prescribed a dietary liquid supplementation during the observation period. Superoxide production in PMN induced by fMLP (a receptor ligand) and phorbol myristate acetate (PMA), which acts directly on protein kinase C. fMLP-induced superoxide generation in the malnourished patients was 55+/-5% of that of the controls. However, the patients retained their capacity, 108+/-6% of control PMN generation, to respond to PMA. In those who received formula supplementation, fMLP-generated *O2- production levels were 48+/-8 and 73+/-13% (P = 0.12) of those of controls at the start and after 3 months, respectively. Corresponding figures in those who were not prescribed supplementation were 57+/-8 and 64+/-4% (P = 0.55). Possibly contributing to reduced host defence, receptor ligand-induced PMN generation of *O2 is significantly lower in chronically ill, elderly patients with PEM than in age-matched healthy controls.

Gamma interferon treatment of patients with chronic granulomatous disease is associated with augmented production of nitric oxide by polymorphonuclear neutrophils.

Treatment with gamma-interferon (IFN-gamma) is associated with reduced frequency and severity of infections in chronic granulomatous disease (CGD), but the mechanism is unknown. Since the inducible nitric oxide (NO) synthase can be amplified by IFN-gamma in murine macrophages, for example, we hypothesized that IFN-gamma might modulate NO release from polymorphonuclear neutrophils (PMNs) in patients with CGD. Eight patients with CGD and eight healthy controls were studied. Each patient was given either 50 or 100 microg of IFN-gamma per m2 on two consecutive days. The production of NO from N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PMNs was assessed as the NG-monomethyl-L-arginine-inhibitable oxidation of oxyhemoglobin to methemoglobin in the presence of catalase and superoxide dismutase. Prior to IFN-gamma treatment, the PMNs from CGD patients produced 372 +/- 27 (mean +/- standard error of the mean) pmol of NO/10(6) PMNs at 45 min, while the control PMNs produced 343 +/- 44 pmol. On day 1 after IFN-gamma treatment, NO production increased to 132% +/- 25% of that for controls, and on day 3 it reached 360% +/- 37% (P < 0.001) of that for controls. On day 8, the values still remained higher, 280% +/- 78% more than the control values. Likewise, the bactericidal capacity of PMNs increased on day 3. The present data show that IFN-gamma treatment of CGD patients is associated with an increased production of NO from PMNs when activated by fMLP. Since these PMNs lack the capacity to produce superoxide anions, it is conceivable that this increase in NO release could be instrumental in augmenting host defense.

Leukocyte Rolling In Vivo Is Mediated by P-Selectin Glycoprotein Ligand-1

Leukocyte rolling, an early and important step in the inflammatory response, is mediated by the selectin family of adhesion molecules. The selectins bind with low affinity to sialylated and fucosylated glycans such as sialyl Lewisx (sLex), but bind with high affinity to only a few specific glycoproteins on cell surfaces. One such glycoprotein is P-selectin glycoprotein ligand-1 (PSGL-1). The relative contributions of low- and high-affinity ligands to leukocyte rolling in vivo are unknown. We show here that a monoclonal antibody to PSGL-1 (PL1) dramatically reduces rolling of human polymorphonuclear neutrophils (PMN) and promyelocytic HL-60 cells in venules of acutely exteriorized rat mesentery. Control PMN and HL-60 cell rolling flux fractions were 39% +/- 3% and 33% +/- 5%, which were reduced by PL1 to 7% +/- 2% and 6% +/- 2%, respectively. Similar reductions were seen with F(ab) fragments of PL1. PL1-treated PMN rolled at significantly higher mean velocities than untreated PMN owing to intermittent rather that continuous interactions. These findings show that interaction of P-selectin with PSGL-1 is required for rolling of myeloid cells in mesenteric venules at physiologic shear stress in vivo.

The 47-kD protein increased in neutrophil actin dysfunction with 47- and 89-kD protein abnormalities is lymphocyte-specific protein

A male child born of related parents suffered recurrent infections because of neutrophil actin dysfunction with increased amounts of a 47- kD protein and decreased amounts of an 89-kD protein (NAD 47/89). The patient and family members were studied to define the nature of the abnormal proteins and to examine their role in the functional defects of neutrophil actin dysfunction (NAD) 47/89 polymorphonuclear neutrophils (PMNs). NAD 47/89 PMNs are defective in motility, microfilamentous cytoskeletal structure, and formyl peptide-induced actin polymerization and express increased amounts of a 47-kD protein and decreased amounts of an 89-kD proteins intermediate abnormality in amount of 47-kD and 89-kD proteins in PMNs from parents and a female sibling suggest the disease is an autosomal recessive disorder. Immunoblots with monoclonal antibody (MoAb1) and polyclonal antibody raised to 47-kD protein showed the 89-kD protein is antigenically distinct from the 47-kD protein and the 89-kD protein is not gelsolin. 125I-actin binding to one-dimensional (1 D) and 2 D gels of PMN proteins from NAD 47/89 proband, family members, and controls showed the 47-kD protein binds actin, is acidic (pl = 4.5 to 4.7), is recognized by the MoAb1, exists on 2-D gels as three distinct actin binding species (MWapp 52 kD, 47-kD, and 44-kD), and is present in control PMNs in lesser amount than in PMNs of NAD 47/89 proband or parents. Immunoaffinity purification of the 47 kD actin binding protein on MoAb1 matrix yielded a multimolecular complex with proteins of MWapp 180 kD, 71 kD, 47 kD and actin. Cloning, sequencing, and expression of a 1.58-kb cDNA selected for MoAb1 reactivity from a HL60 expression library and microsequence of native PMNs, 47-kD actin binding protein showed the overexpressed 47-kD protein is lymphocyte-specific protein 1 (LSP1), which is a known actin binding protein. The results show LSP1 is expressed in PMNs and suggest overexpression of LSP1 is related to the motility and cytoskeletal abnormalities in NAD 47/89 PMNs.

The 47-kD Protein Increased in Neutrophil Actin Dysfunction With 47- and 89-kD Protein Abnormalities Is Lymphocyte-Specific Protein

AbstractA male child born of related parents suffered recurrent infections because of neutrophil actin dysfunction with increased amounts of a 47-kD protein and decreased amounts of an 89-kD protein (NAD 47/89). The patient and family members were studied to define the nature of the abnormal proteins and to examine their role in the functional defects of neutrophil actin dysfunction (NAD) 47/89 polymorphonuclear neutrophils (PMNs). NAD47/89 PMNs are defective in motility, microfilamentous cytoskeletal structure, and formyl peptide-induced actin polymerization and express increased amounts of a 47-kD protein and decreased amounts of an 89-kD proteins intermediate abnormality in amount of 47-kD and 89-kD proteins in PMNs from parents and a female sibling suggest the disease is an autosomal recessive disorder. Immunoblots with monoclonal antibody (MoAbl) and polyclonal antibody raised to 47-kD protein showed the 89-kD protein is antigenically distinct from the 47-kD protein and the 89-kD protein is not gelsolin. 125l-actin binding to one-dimensional (1 D) and 2 D gels of PMN proteins from NAD 47/89 proband, family members, and controls showed the 47-kD protein binds actin, is acidic (pl = 4.5 to 4.7), is recognized by the MoAbl. exists on 2-D gels as three distinct actin binding species (MWapp 52 kD, 47-kD, and 44-kD), and is present in control PMNs in lesser amount than in PMNs of NAD 47/89 proband or parents. Immunoaffinity purification of the 47 kD actin binding protein on MoAbl matrix yielded a multi-molecular complex with proteins of MWapp 180 kD, 71 kD, 47 kD and actin. Cloning, sequencing, and expression of a 1.58-kb cDNA selected for MoAbl reactivity from a HL60 expression library and microsequence of native PMNs, 47-kD actin binding protein showed the overex-pressed 47-kD protein is lymphocyte-specific protein 1 (LSP1), which is a known actin binding protein. The results show LSP1 is expressed in PMNs and suggest overexpres-sion of LSP1 is related to the motility and cytoskeletal abnormalities in NAD 47/89 PMNs.

Neutrophil adherence-augmenting and chemotactic plasma activities in acute myocardial infarction: effect of fibrynolytic treatment

Polymorphonuclear neutrophils (PMNs) participate in the development of myocardial reperfusion injury during fibrynolytic treatment. In 40 patients with acute myocardial infarction, we evaluated the effect of streptokinase treatment on plasma activity augmenting PMN adherence and chemotactic plasma activity in peripheral venous blood with the use of neutrophils obtained from healthy donors. In all patients we observed the appearance of marked plasma chemotactic activity and plasma activity augmenting PMN adherence. Peak values of both plasma activities in the conventionally treated group were reached on the third day following the onset of symptoms. In streptokinase treated patients both plasma activities reached a peak on the second day after the onset of symptoms. Furthermore, streptokinase in vitro induced adherence of control PMNs in a dose-dependent manner, as well as increasing both chemotaxis and random migration of control cells. Thus, both chemotactic plasma activity and neutrophil adherence augmenting plasma activity may be used for monitoring the inflammatory response to myocardial infarction. However, during fibrynolytic treatment the presence of chemotactic stimuli in peripheral blood may be affected by streptokinase per se.

Metabolism of platelet-activating factor in neutrophils isolated from Pichinde virus-infected guinea pigs.

Metabolism of platelet-activating factor (PAF) was studied in cultured polymorphonuclear neutrophils (PMNs) obtained from Pichinde virus-infected strain 13 guinea pigs. Neutrophils obtained from control and infected guinea pigs on postinoculation days 10 and 14 were incubated with [3H]lyso-PAF, [3H]PAF, or [3H]acetate. After incubation for 1 h at 37 degrees C, formation of [3H]acyl-PAF from either [3H]lyso-PAF or [3H]PAF increased significantly in PMNs from infected guinea pigs compared to control PMNs. Furthermore, total radioactivity from [3H]lyso-PAF or [3H]PAF was higher in PMNs from infected animals than in those from controls. However, compared to PAF production by control PMNs, production of PAF by infected PMNs was unchanged. These results suggest that PMNs may not be the major source of increased blood PAF levels during Pichinde viral disease.

Oxidative activity of polymorphonuclear leukocytes after thermal injury.

Since defects in polymorphonuclear neutrophil (PMN) function are associated with an increased risk of infection, we measured the metabolic response of neutrophils from 23 burn patients with a mean burn size of 52%. Neutrophils from burn patients had a different pattern of oxygen consumption than control cells; the rate of QO2 at rest was higher, while the magnitude of the respiratory burst was lower in patient than in control PMNs, depending on whether the cells were incubated in media or normal serum. The burn-induced changes in patient PMN metabolism seem to be due to circulating factors, at least in part, since the pattern of increased resting and decreased stimulated QO2 could be transferred to control cells by incubating them in burn serum. Thus, a thermal injury alters neutrophil metabolism as well as systemic metabolism.

An in vivo hamster bioassay to assess the toxicity of particulates for the lungs

We have developed a short-term bioassay to predict the toxicity of particulates for the lungs using hamsters exposed by intratracheal instillation. After exposure the animals were killed, their lungs were lavaged, and the pulmonary damage was characterized by cellular and biochemical assays of lavage fluid: (a) changes in in situ phagocytic ability of macrophages; (b) damage to the air-blood barrier shown by increases in albumin and red blood cells; (c) inflammation shown by increases in polymorphonuclear neutrophils (PMNs) and macrophages; and (d) cellular damage, measured by the levels of lactate dehydrogenase (LDH), β- N-acetylglucosaminidase, peroxidase, and elastase in the extracellular supernatant fraction of the lavage fluid. The system was calibrated using toxic α-quartz and two nontoxic dusts, aluminum oxide and iron oxide. Increases in albumin and red blood cells one day after exposure were greater following quartz than aluminum oxide and iron oxide; in contrast, a large part of the LDH increase was a nonspecific response to increased dust within the lungs. Most of the indicators, including red blood cell numbers, glucosaminidase, and peroxidase, either approached or were at control levels 4 days after exposure to iron oxide or α-quartz. In α-quartz-exposed animals, macrophage and PMN numbers were more elevated at 4 days that at 1 day and remained elevated for at least 14 days. In contrast, in iron oxide-exposed hamsters, macrophage numbers did not differ from control levels and PMN numbers approached control levels with time. The ability to cause a prolonged infiltration of macrophages and PMNs may be an important determinant of the toxicity of mineral dusts.

The effect of an NADH oxidase inhibitor (hydrocortisone) on polymorphonuclear leukocyte bactericidal activity.

Polymorphonuclear neutrophils (PMN) from patients with chronic granulomatous disease of childhood have impaired bactericidal activity and are deficient in diphosphopyridine nucleotide, reduced form of, (NADH) oxidase. Since hydrocortisone had been shown to inhibit NADH oxidation, experiments were undertaken to determine the effect of hydrocortisone on several parameters of human PMN function. The phagocytic and bactericidal capacity of PMN with or without hydrocortisone (2.1 mM) was determined by quantitation of cell-free, cell-associated, and total bacteria. Phagocytosis of Staphylococcus aureus and several gram-negative rods was unimpaired by the presence of hydrocortisone in the media. In contrast, killing of bacteria was markedly impaired by hydrocortisone. After 30 min of incubation, there were 20-400 times as many bacteria surviving in hydrocortisone-treated PMN as in simultaneously run controls without hydrocortisone. The defect of intracellular killing noted in the presence of hydrocortisone was not related to impaired degranulation. Quantitative kinetic studies of degranulation revealed no difference in the release of granule associated acid phosphatase in hydrocortisone-treated and control PMN after phagocytosis. Electron microscopy of PMN also indicated that the presence of hydrocortisone had no effect on the extent of degranulation after phagocytosis. These observations were confirmed by studies using histochemical techniques to detect lysosomal enzymes. After phagocytosis, hydrocortisone-treated PMN demonstrated less NADH oxidase activity, oxygen consumption, and hydrogen peroxide production than postphagocytic control PMN. In addition, Nitro blue tetrazolium dye reduction was diminished in hydrocortisone-treated PMN.Thus, impairment of NADH oxidase activity in normal human PMN by hydrocortisone results in reduced intracellular killing of bacteria, diminished postphagocytic oxygen consumption, decreased ability to reduce Nitro blue tetrazolium, and decreased hydrogen peroxide production. These abnormalities are similar to those seen in the PMN of patients with chronic granulomatous disease of childhood.