Neutrophil granulocyte function in bacterial infections

Interrogating the sepsis host immune response using cytomics

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2023. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2023 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

Glycine induces enhancement of bactericidal activity of neutrophils

Severe bacterial infections are frequently accompanied by depressed neutrophil functions. Thus, agents that increase the microbicidal activity of neutrophils could add to a direct antimicrobial therapy. Lysophosphatidylcholine augments neutrophil bactericidal activity via the glycine (Gly)/glycine receptor (GlyR) α2/TRPM2/p38 mitogen-activated protein kinase (MAPK) pathway. However, the direct effect of glycine on neutrophil bactericidal activity was not reported. In this study, the effect of glycine on neutrophil bactericidal activity was examined. Glycine augmented bactericidal activity of human neutrophils (EC₅₀ = 238 μM) in a strychnine (a GlyR antagonist)-sensitive manner. Glycine augmented bacterial clearance in mice, which was also blocked by strychnine (0.4 mg/kg, s.c.). Glycine enhanced NADPH oxidase-mediated reactive oxygen species (ROS) production and TRPM2-mediated [Ca²⁺]_i increase in neutrophils that had taken up E. coli. Glycine augmented Lucifer yellow uptake (fluid-phase pinocytosis) and azurophil granule-phagosome fusion in neutrophils that had taken up E. coli in an SB203580 (a p38 MAPK inhibitor)-sensitive manner. These findings indicate that glycine augments neutrophil microbicidal activity by enhancing azurophil granule-phagosome fusion via the GlyRα2/ROS/calcium/p38 MAPK pathway. We suggest that glycine could be a useful agent for increasing neutrophil bacterial clearance.

Emerging drugs for the treatment of sepsis

Septic shock still places a major burden on the healthcare system, although recent years have been marked by the demonstration that corticosteroids and activated protein C may substantially improve survival in selected populations. This review discusses the current management of septic shock and the potential development of new therapeutics following impressive advances in the pathomechanisms of septic shock.

Neutrophil apoptosis, activation and anti-inflammatory cytokine response in granulocyte colony-stimulating factor-treated patients with community-acquired pneumonia

BACKGROUND

Despite antibiotic treatment, the mortality of severe community-acquired pneumonia (CAP), especially in patients with severe comorbidity, remains high. Innate defense mechanisms including polymorphonuclear neutrophil (PMN) activation and survival, orchestrated by cytokines, are primarily responsible for the elimination of bacterial organisms from the alveolus.

OBJECTIVES

The aim of this study was to evaluate the effect of granulocyte colony-stimulating factor (G-CSF) on PMN activation, apoptosis and cytokine response in patients with CAP.

METHODS

Patients received a single dose of G-CSF (1 x 300 or 480 microg s.c.) prior to standard antibiotic treatment (n=8) or standard treatment only (n=8). Apoptosis rate and expression of CD11b, CD66b, CD64 and CD114 surface molecules on systemic PMN were assessed using fluorescence-activated cell sorter analysis. Levels of the interleukin-1 receptor antagonist (IL-1 RA), the soluble tumor necrosis factor receptor inhibitor (sTNF-p55) and G-CSF were measured by ELISA.

RESULTS

In the treatment group, 12 h after G-CSF application, neutrophil count increased, neutrophil activation marker CD11b was stimulated (CD11b: 48.6+/-9.7 vs. 71.2+/-17.7, p<0.01), neutrophil apoptosis decreased (apoptosis: 1.36+/-0.27 vs. 0.2+/-0.12%, p <.01) and the concentration of IL-1RA and sTNF-p55 increased (IL-1RA 136.4+/-72.2 vs. 340.1+/-194.6 ng/ml, p<0.01; sTNF-p55,382+/-4,243 vs. 632+/-4,714 ng/ml, p<0.01; control group nonsignificant). These effects were not seen in the control group.

CONCLUSIONS

The application of a single dose of G-CSF in patients with CAP caused a prolonged survival and increased activation of neutrophils combined with a sustained release of anti-inflammatory cytokines.

Is there a place for granulocyte colony-stimulating factor in non-neutropenic critically ill patients?

Immunoparalysis, characterised by impairments in neutrophil and monocyte/macrophage function, is common in critically ill patients. The theoretical ability of granulocyte colony-stimulating factor (G-CSF) to improve the functions of both neutrophils and monocytes/macrophages provides a rationale for G-CSF therapy in non-neutropenic critically ill patients with infection or a high risk of nosocomial infection. The expression of the receptors that mediate G-CSF effects in neutrophils and monocytes/macrophages is regulated by bacterial products, cytokines and endogenous G-CSF levels, accounting for the variables effects of G-CSF on the neutrophil functions of critically ill patients. This variability should be taken into account when designing studies on the use of G-CSF in ICU-patients. Studies are still needed to identify the subset of patients who may benefit from G-CSF therapy.

Bactericidal activity response of blood neutrophils from critically ill patients to in vitro granulocyte colony-stimulating factor stimulation

OBJECTIVE

Neutrophil function impairment is common in nonneutropenic critically ill patients. Whether granulocyte colony-stimulating factor (G-CSF) may be useful for preventing nosocomial infection in these patients is debated. The response of blood neutrophils from critically ill patients to G-CSF was investigated in vitro.

DESIGN AND SETTING

Prospective study, laboratory investigation in two intensive care units.

PATIENTS

52 critically ill patients without immunosuppression.

MEASUREMENTS

Neutrophils obtained from 52 patients on the 5th day of their intensive care unit stay were incubated with and without G-CSF (1, 10, 100 ng/ml). Reactive oxygen species (ROS) release and bactericidal activity against Staphylococcus aureus and Pseudomonas aeruginosa were evaluated. Plasma cytokines (interleukin 10, tumor necrosis factor alpha, and G-CSF) were measured.

RESULTS

Median values (25th-75th percentiles) indicated no stimulatory effect of G-CSF on neutrophil bactericidal activity against either organism: S. aureus, 100% (95-109) of the unstimulated condition with 1 ng/ml G-CSF, and P. aeruginosa, 102% (98-109) with 1 ng/ml G-CSF. However, wide interindividual variability was found, ranging from marked inhibition to marked stimulation. Similar variability was found for ROS release. No correlations were found between ROS release and bactericidal activities against either bacterial strain. Inhibition of neutrophil bactericidal activity by G-CSF was associated with significantly higher plasma interleukin 10 concentrations. Plasma G-CSF levels were significantly higher in patients whose neutrophil bactericidal activity was unresponsive to G-CSF, suggesting G-CSF receptor downregulation.

CONCLUSIONS

The effect of G-CSF on in vitro neutrophil bactericidal activity varied widely, depending on endogenous levels of G-CSF and was not predictable based on severity scores.

Granulocyte colony-stimulating factor enhances host defenses against bacterial pneumonia following peritonitis in nonneutropenic rats

OBJECTIVE

Polymorphonuclear cell functions frequently are impaired in critically ill patients, and restoration of normal functions could help to prevent nosocomial infections. The aim of this study was to evaluate the effects of pretreatment with granulocyte colony-stimulating factor (G-CSF) on bacterial pneumonia induced 48 hrs after peritonitis (cecal ligation and puncture [CLP]) in rats.

DESIGN

Controlled animal study.

SETTING

Research laboratory of an academic institution.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

First, the CLP model was characterized. Second, alveolar endotoxin instillation allowed us to evaluate the ability of neutrophils to migrate to airspaces after CLP was assessed. In the last set of experiments, CLP was followed by G-CSF treatment as a preventive therapy for subsequent bacterial superinfection induced by alveolar instillation.

MEASUREMENTS AND MAIN RESULTS

CLP induced a brief increase in proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta) at the 6th hr followed by a longer-lived anti-inflammatory response (interleukin-10 increase from days 1 to 3) in plasma, compared with healthy rats. Impaired neutrophil migration to alveolar spaces denoting immunoparalysis was evidenced after endotracheal endotoxin instillation following CLP, compared with non-CLP rats challenged with endotoxin. No such impairment was found when G-CSF (100 microg/kg: glycosylated recombinant human G-CSF, Lenograstim) was given before endotoxin. G-CSF (100 microg/kg 24 and 48 hrs after CLP) given before endotracheal instillation increased bacterial clearance, as shown by counts in both bronchoalveolar lavage (8.9 x 10 +/- 2.8 x 10 colony-forming units/mL vs. 3.3 x 10 +/- 1.5 x 10 colony-forming units/mL with saline) and lung tissue (4.2 x 10 +/- 1.0 x 10 colony-forming units/g vs. 1.5 x 10 +/- 0.6 x 10 colony-forming units/g with saline). Furthermore, G-CSF pretreatment kept clearance in CLP rats similar to that in non-CLP rats challenged with.

CONCLUSION

These results suggest that G-CSF (Lenograstim) may enhance host defenses in rats with peritonitis and immunoparalysis.

Impairment of polymorphonuclear neutrophil functions precedes nosocomial infections in critically ill patients

OBJECTIVE

A postinjury immunodepression involving neutrophil functions has been described in critically ill patients. The aim of this prospective study was to search for a relationship between an impairment of neutrophil functions and the subsequent development of nosocomial infection.

DESIGN

Twenty-one severely ill (simplified acute physiology score II >20 on admission), nonimmunosuppressed patients who were receiving no antibiotics active against methicillin-resistant Staphylococcus aureus and highly resistant Pseudomonas aeruginosa were included. Twelve healthy subjects constituted a control group.

MEASUREMENTS

Neutrophil functions (phagocytosis and bactericidal activity toward S. aureus and P. aeruginosa in homologous plasma, reactive oxygen species secretion) were studied at day 4 +/- 1 after admission, and occurrence of nosocomial infection was prospectively recorded over the following 5 days. Interleukin-10 concentration was assessed by enzyme-linked immunosorbent assay. Results are expressed as median (25th-75th percentiles).

MAIN RESULTS

Six out of the 21 patients acquired a nosocomial infection during the 5 days after blood sampling (infected group). Compared with the patients who did not acquire nosocomial infection (noninfected group, n = 15), the neutrophils of the infected group demonstrated a higher percentage of intracellular bacterial survival (17% [2% to 67%] vs. infected: 62% [22% to 100%], p <.05), leading to an impairment of S. aureus killing in homologous plasma (killed bacteria: 4.93 log(10) colony forming units/mL [4.24-5.29] vs. infected: 3.62 log(10) colony forming units/mL [0.00-4.58], p <.05). Interleukin-10 plasma concentration was higher in infected patients (78 pg/mL [60-83]) compared with noninfected patients (22 pg/mL [14-58], p <.05). By contrast, P. aeruginosa killing was similar in patients whether or not they acquired a nosocomial infection.

CONCLUSION

A decrease in S. aureus killing capabilities of neutrophils can be evidenced within the days before occurrence of a nosocomial infection.

Oxidative metabolism and release of myeloperoxidase from polymorphonuclear leukocytes obtained from blood sedimentation in a Ficoll-Hypaque gradient

Polymorphonuclear neutrophils (PMN) have an important role in the host defence response to infection. These cells produce large amounts of reactive oxygen species (O(2).(-), H(2)O(2) and ONOO(-)) with microbicidal activity. PMN are commonly isolated from peripheral blood by sedimentation through a gradient of density (Ficoll-Hypaque gradient and dextran), yielding a highly homogeneous cellular population. However, some cellular activation due to membrane perturbation is also expected. We studied how the production of reactive oxygen species and release of myeloperoxidase (MPO) from blood PMN are affected by the use of the Ficoll-Hypaque density gradient. PMN isolated by spontaneous sedimentation and total blood were used for comparisons. Lucigenin- and luminol-enhanced chemiluminescence was used to estimate the production of reactive oxygen from intact cells and shown to be higher for cells isolated by density gradient both in the absence and presence of added stimuli. The release of MPO, estimated by the chemiluminescence of the luminol/H(2)O(2) reaction in the supernatant of PMN incubated in the absence and presence of stimuli and absence and presence of cytochalasin B, was also higher for PMN isolated by a density gradient. In conclusion, it was shown that the PMN isolation procedure affects reactive oxygen species production and MPO release and in some cases may cause a misinterpretation of results.

Effects of rhG-CSF on neutrophil functions and survival in sepsis induced diabetic rats

Diabetic patients are more prone to infection and evidence for an immunologic defect superimposed upon the metabolic abnormalities of diabetes is convincing. Neutrophils play a critical role in the host defense mechanism against various bacterial infections, and it is suggested that impaired neutrophil functions cause susceptibility to infections in diabetic patients. To explore the possibility that Granulocyte colony-stimulating factor (G-CSF) may be useful to prevent the morbidity and mortality caused by infections in diabetics. We studied the effect of G-CSF against septicemia in diabetic rats. Forty eight rats were divided into seven equal groups. The IInd, IVth-VIth groups were made diabetic by single intraperitoneal injection of streptozotocin. Fourth, VIth and VIIth groups were made septicemic by cecal ligation and perforation at the end of the second week of streptozotocin injection. G-CSF was subcutaneously injected into IIIrd, Vth and VIth groups. White blood cell count, neutrophil counts and function were determined. Rats in all groups were also observed for seven days for survival. White blood cells, neutrophil and lymphocyte counts and the neutrophil phagocytosis index decreased but neutrophil adherence rate was not different in diabetic group II (p<0.05). All these variables were significantly diminished in diabetes and sepsis-induced group IV (p<0.05). G-CSF injections improved all variables except neutrophil adherence. Cumulative survival ratio was better in G-CSF-injected group VI than in ceftriaxon-administrated group VII (p<0.05). In conclusion, G-CSF increased neutrophil counts, developed neutrophil functions and improved survival. These results suggest that G-CSF may be useful as a drug to prevent bacterial infection in diabetic patients.

Abnormal phagocytic function in children under one year of age

The action of white blood cells (WBC) against Proteus mirabilis was assayed in 22 children following meningitis or septicaemia and compared with that in control groups of: (1) adult volunteers, (2) children undergoing minor surgical procedures for non-infective conditions, and (3) children being investigated for suspected renal disease. WBC bacterial killing tests were normal in all 55 adult volunteers. Abnormal results were obtained in 11 of 22 (50%) children with meningitis or septicaemia, 10 of 21 (47.6%) children undergoing surgery and six of 13 (46%) children with suspected renal disease, thereby indicating that there were no significant differences in phagocytic function among these three groups. Of children aged 1 year or less, 75% had abnormal phagocytic function. The significance of this finding is discussed.

Infections related to the menstrual cycle. A study of five otherwise healthy women with recurrent abscesses and a review of the literature

The purpose of the study was to investigate the in vitro bactericidal function of blood polymorphonuclear leucocytes (PMN) in various phases of the menstrual cycle from otherwise healthy women with recurrent cutaneous abscesses related to the premenstrual phase of the menstrual cycle compared with the bactericidal activity of PMN from healthy women with no inconveniences related to the menstrual cycle. The bactericidal activity against Staphylococcus aureus 502A was investigated and when possible against the patients' own strain. No variation in bactericidal activity was observed during the different phases of the menstrual cycle. PMN from five women with recurrent abscesses related to the premenstrual phase tended to kill fewer S. aureus 502A than PMN from three women in the control group. The literature of immunological defence mechanisms and the occurrence of infections related to the menstrual cycle is reviewed.

Oxidative metabolic products released from polymorphonuclear leukocytes in middle ear fluid during experimental pneumococcal otitis media

To determine whether oxidative metabolic products of phagocytic cells are present in the middle ear during experimental pneumococcal otitis media, we measured the concentration of myeloperoxidase (MPO) in middle ear fluid (MEF) and the capacity of neutrophils isolated from MEF and peripheral blood to produce MPO and superoxide anion (O2-) after in vitro stimulation. Free MPO in MEF was significantly increased 24 and 48 h after either viable or nonviable pneumococci were inoculated into the middle ear. In vitro-stimulated production of MPO and O2- from middle ear neutrophils was significantly less than that from peripheral blood neutrophils 24 h after nonviable pneumococci were inoculated but similar to it after 48 h. Twenty-four hours after viable pneumococci were inoculated, middle ear neutrophils stimulated in vitro produced less MPO but the same amount of O2- as did blood neutrophils. Oxidative metabolic products, therefore, are released from phagocytic cells into the MEF during pneumococcal otitis media, and future studies will need to define the contribution of these products to acute and chronic middle ear tissue injury.

Intraabdominal sepsis: effects on polymorphonuclear leukocyte Fc receptor-mediated phagocytosis

In vitro studies have shown that phagocytic cells are capable of undergoing activation in response to inflammatory signals and that the activation process is quite complex. A relationship between polymorphonuclear leukocyte (PMN) Fc receptor-mediated phagocytosis and oxidative metabolism has been seen in humans. We have sequentially examined circulating polymorphonuclear leukocytes (PMNs) from a total of 13 postoperative swine with either no sepsis, untreated intraabdominal sepsis, or treated intraabdominal sepsis to determine phagocytic activity over 8 postoperative days (POD). Products of the oxidative burst (i.e., myeloperoxidase) reduced the phagocytic activity of nonseptic swine PMN. Phagocytic activity was augmented by inhibiting the nonseptic swine oxidative burst with 10 mM sodium azide (an inhibitor of myeloperoxidase). In swine with untreated intraabdominal sepsis, PMN Fc receptor-mediated phagocytosis exhibited a biphasic response. An initial (between POD1 and POD4) increase in PMN function was followed by a subsequent (between POD4 and POD8) decrease in PMN function. Partial preservation of phagocytic capability was seen when swine were reexplored on POD4 and had their intraabdominal sepsis treated. These results indicate that (1) as in humans, nonseptic swine PMN Fc receptor-mediated phagocytosis is augmented by inhibition of the PMN respiratory burst; (2) untreated intraabdominal sepsis produces an initial increase and subsequent decrease in PMN Fc receptor-mediated phagocytosis; (3) early treatment of intraabdominal sepsis results in partial restoration of PMN Fc receptor-mediated phagocytosis.

Studies on phagocytosis in patients with acute bacterial infections

Polymorphonuclear leukocytes (PMN) and monocytes from 20 patients with acute bacterial infections were examined for phagocytic function. PMN of patients expressed markedly enhanced phagocytosis as measured by the ingestion of erythrocyte (E)IgG and IgG/C3b-coated E. Phagocytosis of E coated with C3b alone was not seen, while low levels of ingestion of iC3b-E by patients' PMNs was noted. Monocytes from patients and controls expressed similar phagocytic activity in a fixed endpoint assay; however, the kinetics of phagocytosis by patients' monocytes was strikingly faster. Superoxide anion (O2.) and myeloperoxidase activities were similar to controls in PMN of four patients studied on day 1 of admission. PMN from two of three patients studied longitudinally showed an initial elevation in EIgG phagocytosis, which fell to normal levels by day 4, concomitantly with increased O2. generation and clinical improvement. Phagocytosis remained elevated in the third patient who did not clear his septicemia. Surface membrane FcRII, FcRIII, CR1, and CR3 were similar on patient and control PMN. In contrast, FcRI was increased on PMN of five of seven patients by monomeric IgG binding, and on two of two patients by monoclonal anti-FcRI binding. Thus, PMN and monocytes of patients with acute bacterial infections are either upregulated with regard to phagocytic function or are less susceptible to downregulation than are normal cells. This presumably would have a beneficial effect on host defenses during infection.

Effects of two macrolide antibiotics on human leukocyte membrane receptors and functions

Polymorphonuclear granulocytes (PMNs) and lymphocytes from healthy persons were incubated in varying concentrations of erythromycin and RU 28965, a new macrolide antibiotic. Incubation in erythromycin - even in high dilutions - caused a significant increase in the percentage of PMNs bearing receptors for the Fc portion of IgG (Fc gamma R) and for C3b (C3bR) as measured by rosette formation with EA (erythrocyte-antibody) and EAC (erythrocyte-antibody-complement) indicator cells. This effect could not be removed by extended washing of the cells. Incubation in RU 28965 had a similar effect, except for a decrease in EA and EAC rosetting cells at high concentrations (200 mg/l). Phagocytosis, as measured by chemiluminescence, and random migration of PMNs were unaffected by erythromycin. Chemotaxis under agarose was decreased after incubation in erythromycin or RU 28965. Erythromycin incubation increased the percentage of lymphocytes bearing receptors for sheep erythrocytes (E), but had no effect on the proportion of lymphocytes rosetting with EA or EAC, or on lymphocyte responses to mitogens PHA, conA, or PWM.

Impaired neutrophil function in intestinal lymphangiectasia

Impaired neutrophil chemotaxis and phagocytosis were shown in three patients with intestinal lymphangiectasia. Abnormalities in cell associated and serum derived activity occurred, and possible mechanisms are suggested.

Oxygen radical production by neutrophils from patients with bacterial infection and rheumatoid arthritis. Measurement of hydrogen peroxide may most accurately represent enhancement of oxygen radical production during infection

The production of three kinds of oxygen radicals (superoxide, hydrogen peroxide, and hydroxyl radicals) by neutrophils from patients with bacterial infection or rheumatoid arthritis was measured. The stimulators used in this study were opsonized zymosan (1 mg/ml), phorbol myristate acetate (20 ng/ml), A23187 (1 microM), and platelet activating factor (1 microM). Oxygen radical production by neutrophils from patients with rheumatoid arthritis was not significantly different from that of the control group. Hydrogen peroxide production by the neutrophils from patients with bacterial infection was significantly enhanced by only opsonized zymosan, but the production of the other kinds of oxygen radicals was not. Cytochalasin B reduced the production of hydrogen peroxide induced by opsonized zymosan more markedly than that of any other kind of oxygen radical. The measurement of hydrogen peroxide is suggested to be the most accurate indicator of the enhancement of intracellular production of oxygen radicals by neutrophils during infection.

Comparison of blood and peritoneal neutrophil activity in rabbits with and without peritonitis

The neutrophil (polymorphonuclear cell, or PMN) function is an essential component of the host defense against infection. However, infection itself may alter PMN activity. To investigate both the effects of infection on PMN activity and PMN activity on survival, we evaluated control and infected blood and peritoneal PMN phagocytosis, chemotaxis, and superoxide anion production in rabbits with and without peritonitis. Control blood and peritoneal PMNs were obtained from noninfected rabbits which were subjected to intraperitoneal infusion of sterile hypertonic saline. Infected blood and peritoneal PMNs were obtained from rabbits which had undergone appendiceal devascularization and ligation 18 hr earlier. Phagocytosis was similar in all groups except for a threefold increase in normal peritoneal PMNs. Chemotaxis was inhibited by infection in the blood and peritoneal PMNs. Normal peritoneal PMNs also had decreased chemotaxis. Superoxide anion production was comparable in the infected and control blood; however, both control and infected peritoneal PMNs had elevated superoxide anion production. Of the infected rabbits, four died in 5 days or less. Of the six that lived, two developed intraabdominal abscesses. Blood and peritoneal PMN activity was similar in all rabbits despite their outcome. We conclude that (1) blood and peritoneal PMNs have different basal activities and responses to infection; (2) the milieu of the peritoneal cavity appears to alter the PMNs present; and (3) PMN activity did not predict morbidity or mortality.

Modification of the neutrophil Fc receptor by neutrophil granule products: its significance for phagocytosis and bactericidal activity

Preincubation of neutrophils with various amounts of autologous neutrophil granule products induced a dose-dependent decrease in neutrophil Fc receptor expression. However, neutrophil granule products did not affect the neutrophil phagocytic and bactericidal activities.

Gram-negative bacillary infections. Pathogenic and pathophysiologic correlates

Gram-negative bacillary infections continue to be extremely important. Escherichia coli is the single most frequently encountered pathogen, followed by organisms belonging to the tribe Klebsiella-Enterobacter-Serratia and Proteus-Providencia. Pseudomonas aeruginosa, although it receives considerable (perhaps excessive) attention, is found relatively less frequently, occurring principally in the hospitalized patient who is immunocompromised. Many factors, both host and microbial, are responsible for invasiveness, virulence, and pathogenicity of gram-negative bacilli, but their relative roles, importance, and the pathophysiologic reactions they trigger are yet to be precisely defined. Certain aspects of many (but certainly not all) of the pathogenic correlates considered important in gram-negative bacillary infections, such as microbial flora, local barriers, surface and serum antibodies, complement, cell-mediated immunity, slime production, capsules, pili, endotoxin, cell wall components, extracellular products, and inoculum size are discussed herein. Points at which preventive or therapeutic strategies might be developed are offered. The benefits of antibiotics in managing susceptible gram-negative bacillary infections appear to be plateauing. If further advances are to be made in the therapy of these infections, new approaches to rapidly identifying the responsible etiologic agent and a better understanding of the factors responsible for invasiveness, virulence, and pathogenicity are needed.

[Anomalies of the membrane receptors of blood phagocytic cells in nosocomial pulmonary infections]

Patients in intensive care units have frequent and severe opportunistic bacterial pneumoniae, even if they were previously free from respiratory disease. A search was made in these patients for possible immune deficiencies. Granulocyte and monocyte phagocytic activities were studied separately in 17 patients with bacterial bronchopneumonia (male: 13, female: 4; age: 41 +/- 5 yr). The ability of three types of particles (opsonized zymosan, immunoglobulin coated and glutaraldehyde-treated sheep red cells) to trigger ingestion was measured. Cells were tested either in normal AB serum or in the presence of patient's serum. A substantial 40% decrease of the fraction of granulocytes ingesting zymosan was found in our experimental conditions (p less than 0.001). Activity with the other particles was not significantly altered. Patients' sera were at least as efficient as a pool of normal sera in opsonizing zymosan. Furthermore, no phagocytic inhibitor was found in the patients tested. Underlying mechanisms for these abnormalities remain unknown, but a better understanding of the aetiology of the altered bactericidal function of phagocytic cells is required before suggesting immunomodulating treatments.

Differences in phagocytic/adherence properties between normal neutrophils

Neutrophils, serum opsonins and staphylococci were incubated at 37 degrees C with continuous end-over-end rotation. The observed frequency of neutrophils with 0, 1, 2... staphylococci deviated systematically from that expected for a Poisson distribution. This suggests marked differences in phagocytosis/adherence between the neutrophils, indicating different neutrophil populations.

In vitro function of canine neutrophils during experimental inflammatory disease

The effect of acute inflammation on neutrophil function in the dog was studied by measuring in vitro phagocytosis and killing of Staphylococcus aureus. Phagocytosis was not impaired after 30 or 60 minutes and bactericidal activity was not impaired after 60 minutes incubation. However, average bactericidal activity after 30 minutes incubation was diminished significantly (P less than 0.01). Wide variations in bactericidal activity after 30 minutes incubation during the course of the inflammation did not correlate with neutrophil count, number of toxic neutrophils, or clinical course of the inflammation. These results indicate that a defect in bactericidal activity can occur in dogs with severe inflammatory disease, and that repeated assays, rather than single determinations, may be needed to detect this dysfunction.

Membrane receptors on human neutrophils in oral bacterial infections

Experiments were performed to examine the function of neutrophil membrane receptors in oral bacterial infections. For this purpose, Fc and C3b receptors on human peripheral blood neutrophils and exudate neutrophils obtained from subcutaneous abscesses were studied by using the rosette-forming method.

Combined neutrophil and T-cell deficiency: initial report of a kindred with features of the hyper-IgE syndrome and chronic granulomatous disease

A six year old female presented with a recent history of pyoderma gangrenosum involving her legs and arms associated with an episode of Mycoplasma-like pneumonia. This was followed by Aspergillus osteomyelitis involving her left ulna and right femur. Both the skin lesions and the osteomyelitis responded to prolonged treatment with antifungal and antibiotic agents. Investigation of this patient revealed (1) an elevated serum IgE (4,800 units/ml), (2) defect in neutrophil chemotaxis that appeared to be due to immune complexes, (3) an abnormal nitroblue tetrazolium (NBT) result (0 percent stimulated and unstimulated), and (4) depressed mitogen responses to concanavalin A, phytohemagglutinin, and pokeweed mitogen, negative results of intradermal skin tests, and negative dinitrochlorobenzene (DNCB) sensitization. The patient's clinically unaffected sibling had similar findings except for a positive DNCB response. In both children, intracellular bacterial killing of catalase-positive and negative organisms was normal. Kindred studies revealed widespread T-cell abnormalities consistent with autosomal dominant inheritance. Tissue typing studies showed that affected siblings shared the A1, B8, DR3 haplotype. This kindred is unique in that both the proband and the sibling have abnormalities of both the hyper-IgE syndrome and chronic granulomatous disease.

Polymorphonuclear leukocyte function in bacterial and viral infections

Chemiluminescence (CL) production by polymorphonuclear leukocytes (PMNLs) was examined in 63 patients with bacterial infections and 63 healthy controls. The production was significantly higher in the patients (mean +/- standard error = 134.5 +/- 5.0 X 10(3) cpm) than in the controls (118.9 +/- 2.5 X 10(3) cpm; p less than 0.05). In 38 patients CL values were within the normal range and in 19 patients above. CL production below that of any control occurred in 6 patients: 3 (of 4) with staphylococcal endocarditis, 2 (of 4) with pneumococcal meningitis and 1 with salmonella septicaemia and osteomyelitis. PMNL hexose monophosphate shunt activity as measured by glucose metabolism correlated with CL production. Patients with low CL production more often had large numbers of juvenile and immature myeloid cells in the peripheral blood than patients with normal or high CL values. 3/6 patients with low CL values died, 2/38 with normal and 0/19 with high values. Directed and spontaneous PMNL migration was examined in 39 of the 63 patients with bacterial infections. 13 patients had PMNLs with higher directed and 16 with higher spontaneous migration capacity than their corresponding controls. The remaining patients had PMNLs with lower migration capacity. 2 of the 39 patients died. Each had PMNLs with low migration capacity. CL production by PMNLs was examined in 16 patients with viral infections and 16 healthy controls. The production was significantly lower in the patients (mean +/- standard error = 105.5 +/- 6.6 X 10(3) cpm) than in the controls (129.1 +/- 5.3 X 10(3) cpm; p less than 0.01). 15 patients had lower values than their corresponding controls. The PMNL migration capacity was also lower in the patients. These findings indicate that the majority of patients with bacterial infections have PMNLs with normal or increased function. However, some patients have reduced PMNL function and this reduction may contribute to a fatal outcome of the disease. Patients with viral infections usually have reduced PMNL function.

Effects of surgery on neutrophil granulocyte function

The high incidence of postoperative infections raises the possibility of a reduced defense to infection during this period. For this reason, neutrophil function and enzyme activity were investigated after surgical trauma. The microbicidal ability of neutrophils was markedly impaired within 2 h of elective abdominal hysterectomy, but phagocytosis was unaffected. Loss of microbicidal activity was associated with loss of the lysosomal enzyme myeloperoxidase. It is suggested that these changes are due to activation and partial degranulation of circulating neutrophils. Defective microbial killing by individual cells should be compensated by an accompanying rise in the number of circulating neutrophils.

Neutrophil function in infection-prone children

Seven variables connected with the function of the neutrophil granulocyte were studied in 24 children who had undue susceptibilities to infections. The phagocytosis rate of IgG-coated latex particles by the patients' neutrophils was significantly reduced compared with an age-matched control group. The chemokinetic effect of patients' sera on normal polymorphonuclear neutrophil leucocytes was reduced too, especially in heated (56 degrees C, 30 min) serum. Spontaneous chemotactic activity in the patients' sera was significantly lower than in sera from healthy adults and from the age-matched control group. A functional index based on the 7 variables of neutrophil function was constructed. The score of the functional index was correlated to the severity of the patients' clinical condition and discriminated well between normal children and those with undue susceptibility to infections.

Defective bactericidal function of polymorphonuclear neutrophils in children with measles

Killing capacities of polymorphonuclear neutrophils (PMN) and the serum opsonic activity were investigated in 15 children with measles. Seven of them had bacterial infection secondary to the measles. The mean values for killing capacities of the patients were significantly impaired when they were compared with those of the control group which consisted of 15 healthy age-matched children (p less than 0.001). These defects were found to be present during the early stages of the measles. The serum opsonic activity was found to be normal.

Impaired neutrophil function and myeloperoxidase deficiency in pregnancy

The ability of neutrophils to phagocytose and kill Candida guilliermondii was investigated in 28 pregnant women and compared wtih 29 healthy controls. Phagocytosis was normal, but the ability to kill and digest Candida was reduced to 65% of normal. Quantitative myeloperoxidase measurement revealed a considerable reduction of this enzyme (55% of normal) while neutrophil alkaline phosphatase levels were nearly twice as high as in normals. It is suggested that both lack of myeloperoxidase and impaired candidacidal ability result from the discharge of the neutrophil's granules during previous phagocytosis of antibody-antigen complexes in the circulation.

[Oxygen-dependent influence of lipopolysaccharide endotoxin on polymorphonuclear leukocytes (author's transl)]

In in vitro experiments the effect of bacterial endotoxin (Lipopolysaccharide E. coli O 26 :B 6) on the ingestion, NBT reduction, and the formation of cytoplasmic vacuoles of polymorphonuclear leukocytes in the atmosphere of 21 vol-% O2 and 99.9 vol-% N2, respectively, was tested. High concentrations of endotoxin in O2-atmosphere cause an inhibition of the functions and a stimulation of vacuole formation, N2 atmosphere shows these effects of endotoxin on the ingestion and vacuole formation, if at all, in a lesser degree. These results show that endotoxin in high concentrations possibly causes an auto-oxidation of the polymorphonuclear leukocytes. This interpretation of the results is in accord with findings of other authors.

Cytochemical investigation of neutral proteases in polymorphonuclear (PMN) neutrophils in acute inflammatory diseases

Neutral proteases can be released from PMN neutrophils in blood smears from healthy subjects by incubation with NaCl-borate buffer. The activity of the PMN proteases can be revealed by the degradation of erythrocytes and plasma within ring-shaped areas centered around each neutrophil (halo effect). During the acute stage of various inflammatory diseases (pneumonia, meningitis, cholecystitis, etc.) the activity of neutral PMN proteases is substantially reduced, as reflected by reduced halo formation. After recovery, halo formation returns to normal. Temporary lowering of neutral PMN proteases is thus one of a series of functional defects of PMN neutrophils which are detectable in the course of acute infectious diseases. These include reduced phagocytosis, altered chemotaxis and reduced bactericidal function. The cytochemical test for neutrophilic granulocyte function used in the present investigation is especially practical by comparison with the other techniques: it saves time and is simple to perform.

Sequestration of staphylococci at an inaccessible focus

The persistence of staphylococcal arthritis in a patient treated with nafcillin was attributed to intracellular sequestration of staphylococci. These intraphagocytic organisms were protected against bactericidal activity. The infection was cleared by rifampin--an agent which can penetrate leucocyte membranes. When clinical infections do not respond to seemingly adequate antimicrobial treatment, intracellular persistence of bacteria should be considered.

Activation of the bactericidal capacity of polymorphonuclear granulocytes after surgery, measured with a new in vitro assay

A classic in vitro polymorphonuclear (PMN) granulocyte bactericidal system was used alongside a newly developed modification to see whether the new assay would increase the possibility to detect a stimulation of PMN bactericidal functions. In the new assay each granulocyte was provided with 30--40 bacteria, which is quite close to the maximal killing capacity (usually 60 bacteria per PMN). Granulocytes were obtained from 8 patients the day before, the day after and 2 d after they underwent thoracotomy with cardiopulmonary by-pass (CPS). The granulocytes from all patients showed an increased capacity to kill Staph. aureus in vitro 2 d after the operation, compared to before, when the submaximal bacterial concentration per granulocyte was used, whereas no change was observed with the standard bacterial concentration (3--4 bacteria per granulocyte). Thus, the new assay might make it possible to observe an enhanced PMN bactericidal ability.

Recurrent Pseudomonas infection associated with neutrophil dysfunction

A 72-year-old male is described with a history of 4 episodes of Pseudomonas aeruginosa sepsis and chronic otitis media caused by pseudomonas species. In vitro testing of the patient's polymorphonuclear leukocytes (PMNs) revealed profoundly abnormal chemotactic responses and defective intracellular killing of Ps. aeruginosa, Staphylococcus aureus and Escherichia coli. Chemiluminescence production by the patient's PMNs in response to opsonized zymosan as well as endotoxin stimulated nitroblue tetrazolium dye reduction were markedly depressed. These data indicate the presence of a profound, apparently acquired, defect in PMN function in an elderly male. Detailed evaluation of adult patients with recurrent infections may reveal similar, apparently acquired defects in PMN function.

A cerebrospinal fluid leucocidin in pyogenic meningitis

Cerebrospinal fluid (CSF) samples were tested for their cytotoxicity to polymorphonuclear neutrophil leucocytes (PMN) using a 51Cr release assay. Most samples from patients with pyogenic meningitis damaged PMN while normal CSF samples did not. No difference was found between the cytotoxic activity of CSF from patients with pneumococcal meningitis and from patients with meningococcal meningitis. It is, therefore, unlikely that a CSF leucocidin plays an important part in producing the high mortality of pneumococcal meningitis.

Neutrophil and eosinophil granulocytes in bacterial infection: sequential studies of cellular and serum levels of granule proteins

The intraneutrophilic concentrations of lactoferrin, myeloperoxidase, collagenase and chymotrypsin-like cationic proteins were measured sequentially during acute bacterial infection. The serum levels of lactoferrin and myeloperoxidase were also followed as well as the 'eosinophil' cationic protein as a marker for eosinophil leucocytes. During the early course of infection there was a profound but reversible decrease of intraneutrophilic lactoferrin. The levels of cellular collagenase and chymotrypsin-like cationic proteins also tended to decrease reversibly during day 2-8 in most cases; myeloperoxidase levels were normal except for two cases. Serum myeloperoxidase and lactoferrin correlated with blood neutrophil counts. In spite of the absence of peripheral eosinophils the 'eosinophil' cationic proteins of serum were increased on the first day of infection, which may reflect increased eosinophil turnover.

Impaired neutrophil function and myeloperoxidase deficiency in myeloid metaplasia

The ability of neutrophils to phagocytose and kill Candida guilliermondii was investigated in 12 patients with myeloid metaplasia (MM). Following ingestion there was a considerable impairment in the ability of MM neutrophils to kill and digest Candida which was not explained by the very mild impairment in phagocytosis. Quantitative myeloperoxidase measurement revealed an overall deficiency of this enzyme in MM neutrophils and a highly significant correlation between low myeloperoxidase levels and impaired candidacidal activity. Neutrophils from patients with myeloid metaplasia show a pattern of defective microbial killing, high alkaline phosphatase activity and low myeloperoxidase activty which is similar to that seen in severe infections and distinct from chronic granulocytic leukaemia. The cells of one patient with particularly low myeloperoxidase and defective microbial killing were further studied both cytochemically and by electron microscopy. The azurophilic granules of his neutrophils were present in normal numbers and contained normal amounts of acid phosphatase but they lacked myeloperoxidase.

Obesity, plasma lipids and polymorphonuclear (PMN) granulocyte functions

20 obese subjects were compared with 20 controls with normal weight regarding their polymorphonuclear (PMN) granulocyte functions, and plasma lipids. The obese subjects showed a significantly decreased PMN bactericidal capacity, and increased PMN adherence. No differences were found in their mean PMN chemotaxis and opsonic capacity of plasma. The values of plasma triglycerides and free fatty acids were higher in the obese, while plasma cholesterol and phospholipids corresponded to the control values. The changes in granulocyte function did not correlate significantly to plasma lipid levels or to body weight and Broca's index in either group. --It is concluded that changes in granulocyte function occur in obesity, but are not related to plasma lipids or degree of overweight.

Cryopreservation of human granulocytes in liquid nitrogen

Human granulocytes (PMNL) were successfully cryopreserved for up to 14 months. The PMNL (1-2 X 10(7)/ml) were stored in 2-ml ampoules in the gas phase of liquid nitrogen at a temperature between -160 degrees C and -196 degrees C using dimethylsulphoxide (DMSO 10%) as cryoprotectant. Morphology and phagocytic and bactericidal capacity were best preserved by adding fetal calf serum to the freezing mixture, by using an interrupted cooling process, by washing the thawed PMNL in fresh freeze-dried plasma, and centrifuging at 600 g for no more than two minutes. Careful post-thaw handling of the cells was an important factor in preserving function. These preliminary studies indicate that useful numbers of PMNL can be recovered in a functional state after storage for long periods in liquid nitrogen.