Neutrophil function screening in patients with chronic granulomatous disease by a flow cytometric method

Current Flow Cytometric Assays for the Screening and Diagnosis of Primary HLH

Advances in flow cytometry have led to greatly improved primary immunodeficiency (PID) diagnostics. This is due to the fact that patient blood cells in suspension do not require further processing for analysis by flow cytometry, and many PIDs lead to alterations in leukocyte numbers, phenotype, and function. A large portion of current PID assays can be classified as “phenotyping” assays, where absolute numbers, frequencies, and markers are investigated using specific antibodies. Inherent drawbacks of antibody technology are the main limitation to this type of testing. On the other hand, “functional” assays measure cellular responses to certain stimuli. While these latter assays are powerful tools that can be used to detect defects in entire pathways and distinguish variants of significance, it requires samples with robust viability and also skilled processing. In this review, we concentrate on hemophagocytic lymphohistiocytosis (HLH), describing the principles and accuracies of flow cytometric assays that have been proven to assist in the screening diagnosis of primary HLH.

An adult autosomal recessive chronic granulomatous disease patient with pulmonary Aspergillus terreus infection

Background

Genetic mutations that reduce intracellular superoxide production by granulocytes causes chronic granulomatous disease (CGD). These patients suffer from frequent and severe bacterial and fungal infections throughout their early life. Diagnosis is usually made in the first 2 years of life but is sometimes only diagnosed when the patient is an adult although they may have suffered from symptoms since childhood.

Case presentation

A 26-year-old man was referred with weight loss, fever, hepatosplenomegaly and coughing. He had previously been diagnosed with lymphadenopathy in the neck at age 8 and prescribed anti-tuberculosis treatment. A chest radiograph revealed extensive right-sided consolidation along with smaller foci of consolidation in the left lung. On admission to hospital he had respiratory problems with fever. Laboratory investigations including dihydrorhodamine-123 (DHR) tests and mutational analysis indicated CGD. Stimulation of his isolated peripheral blood neutrophils (PMN) with phorbol 12-myristate 13-acetate (PMA) produced low, subnormal levels of reactive oxygen species (ROS). Aspergillus terreus was isolated from bronchoalveolar lavage (BAL) fluid and sequenced.

Conclusions

We describe, for the first time, the presence of pulmonary A. terreus infection in an adult autosomal CGD patient on long-term corticosteroid treatment. The combination of the molecular characterization of the inherited CGD and the sequencing of fungal DNA has allowed the identification of the disease-causing agent and the optimal treatment to be given as a consequence.

In vitro interferon γ improves the oxidative burst activity of neutrophils in patients with chronic granulomatous disease with a subtype of gp91phox deficiency

AIM OF THIS STUDY

Chronic granulomatous disease (CGD) is a genetically heterogeneous primary immunodeficiency caused by a defect in phagocyte production of oxygen metabolites, and resulting in infections produced by catalase-positive microorganisms and fungi. Interferon γ (IFN-γ) has a multitude of effects on the immune system. Although preliminary studies with CGD patients on treatment with IFN-γ showed that it enhanced phagocytosis and superoxide production, ongoing studies did not reveal a significant increase of this function. Here we investigated the oxidative capacity of phagocytes in different subtypes of CGD patients on treatment with IFN-γ in vitro.

MATERIAL AND METHODS

Fifty-seven patients with CGD from 14 immunology centres were enrolled to our multi-centre study. Twenty-one patients were studied as controls. Oxidative burst assay with dihydrorhodamine 123 (DHR) was used and the stimulation index (SI) was calculated with respect to CGD subtypes in both neutrophils and monocytes before, and then one and 24 hours after adding IFN-γ.

RESULTS

Upon comparison of the SIs of the patients' neutrophils before in vitro IFN-γ at hour 0, and after adding IFN-γ at hour 1 and 24 were compared, and the differences were determined between hours 0-24 and hours 1-24. This difference was especially apparent between hours 1-24. In CGD subtypes, particularly in gp91phox subtype, it was seen that, following in vitro IFN-γ, SIs of neutrophils began to increase after hour 1, and that increase became more apparent at hour 24.

CONCLUSIONS

Our study showed that IFN-γ treatment may increase the oxidative bursting activity by increasing the superoxide production in neutrophils, particularly in gp91phox subtype.

Immune deficiency disorders involving neutrophils

This review addresses current thinking on the diagnosis, causation and management of common and rare primary disorders of granulocytes. The genetic basis of many of these disorders is now understood. Increased awareness is necessary to ensure that these disorders are identified promptly and treated appropriately.

The Mammalian circadian clock gene per2 modulates cell death in response to oxidative stress

Living in the earth’s oxygenated environment forced organisms to develop strategies to cope with the damaging effects of molecular oxygen known as reactive oxygen species (ROS). Here, we show that Per2, a molecular component of the mammalian circadian clock, is involved in regulating a cell’s response to oxidative stress. Mouse embryonic fibroblasts (MEFs) containing a mutation in the Per2 gene are more resistant to cytotoxic effects mediated by ROS than wild-type cells, which is paralleled by an altered regulation of bcl-2 expression in Per2 mutant MEFs. The elevated survival rate and alteration of NADH/NAD⁺ ratio in the mutant cells is reversed by introduction of the wild-type Per2 gene. Interestingly, clock synchronized cells display a time dependent sensitivity to paraquat, a ROS inducing agent. Our observations indicate that the circadian clock is involved in regulating the fate of a cell to survive or to die in response to oxidative stress, which could have implications for cancer development and the aging process.

Activation of both protein kinase A (PKA) type I and PKA type II isozymes is required for retinoid-induced maturation of acute promyelocytic leukemia cells

Acute promyelocytic leukemia (APL) is characterized by granulopoietic differentiation arrest at the promyelocytic stage. In most cases, this defect can be overcome by treatment with all-trans-retinoic acid (ATRA), leading to complete clinical remission. Cyclic AMP signaling has a key role in retinoid treatment efficacy: it enhances ATRA-induced maturation in ATRA-sensitive APL cells (including NB4 cells) and restores it in some ATRA-resistant cells (including NB4-LR1 cells). We show that the two cell types express identical levels of the Cα catalytic subunit and comparable global cAMP-dependent protein kinase A (PKA) enzyme activity. However, the maturation-resistant NB4-LR1 cells have a PKA isozyme switch: compared with the NB4 cells, they have decreased content of the juxtanuclearly located PKA regulatory subunit IIα and PKA regulatory subunit IIβ, and a compensatory increase of the generally cytoplasmically distributed PKA-RIα. Furthermore, the PKA regulatory subunit II exists mainly in the less cAMP-responsive nonautophosphorylated state in the NB4-LR1 cells. By the use of isozyme-specific cAMP analog pairs, we show that both PKA-I and PKA-II must be activated to achieve maturation in NB4-LR1 as well as NB4 cells. Therefore, special attention should be paid to activating not only PKA-I but also PKA-II in attempts to enhance ATRA-induced APL maturation in a clinical setting.

Troubleshooting the dichlorofluorescein assay to avoid artifacts in measurement of toxicant-stimulated cellular production of reactive oxidant species

INTRODUCTION

The dichlorofluorescein (DCF) assay is a popular method for measuring cellular reactive oxidant species (ROS). Although caveats have been reported with the DCF assay and other compounds, the potential for artifactual results due to cell-free interactions between the DCF compound and toxicants has hardly been explored. We evaluated the utility of the DCF assay for measuring ROS generation by the toxicants mono-(2-ethylhexyl) phthalate (MEHP), and tetrabromobisphenol A (TBBPA).

METHODS

DCF fluorescence was measured spectrofluorometrically after a 1-h incubation of toxicants with 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate (carboxy-H2DCFDA). MEHP was incubated with carboxy-H2DCFDA in cell-free solutions of Hank's buffered salt solution (HBSS), or in Royal Park Memorial Institute (RPMI) medium with or without fetal bovine serum. TBBPA was incubated with carboxy-H2DCFDA in cell-free HBSS and with human trophoblast cells (HTR8/SVneo cells).

RESULTS

MEHP did not increase fluorescence in solutions of carboxy-H2DCFDA in HBSS or RPMI medium without serum. However, MEHP (90 and 180μM) increased DCF fluorescence in cell-free RPMI medium containing serum. Furthermore, serum-free and cell-free HBSS containing 25μM TBBPA exhibited concentration-dependent increased fluorescence with 5-100μM carboxy-H2DCFDA (p<0.05), but not 1μM carboxy-H2DCFDA. In addition, we observed increased fluorescence in HTR8/SVneo cell cultures exposed to TBBPA (0.5-25μM) (p<0.05), as we had observed in cell-free buffer.

DISCUSSION

MEHP demonstrated an interaction with serum in cell-free generation of DCF fluorescence, whereas TBBPA facilitated conversion of carboxy-H2DCFDA to the fluorescent DCF moiety in the absence of serum. Because TBBPA increased fluorescence in the absence of cells, the increased DCF fluorescence observed with TBBPA in the presence of cells cannot be attributed to cellular ROS and may, instead, be the result of chemical activation of carboxy-H2DCFDA to the fluorescent DCF moiety. These data illustrate the importance of including cell-free controls when using the DCF assay to study toxicant-stimulated cellular production of ROS.

Chronic granulomatous disease presenting as aseptic ascites in a 2-year-old child

Chronic granulomatous disease (CGD) is a rare inherited immunodeficiency syndrome that results from abnormal nicotinamide adenine dinucleotide phosphate (NADPH) oxidase function. This defect leads to recurrent catalase-positive bacterial and fungal infections as well as associated granuloma formation. We review the case of a 2-year-old boy who presented with ascites and fever of an unknown origin as manifestations of CGD. Cultures were negative for infection throughout his course, and CGD was suspected after identification of granulomas on peritoneal biopsy. Genetic testing revealed a novel mutation in the CYBB gene underlying his condition. This paper highlights the importance of considering CGD in the differential diagnosis of fever of unknown origin and ascites in children.

Chronic granulomatous disease: a review of the infectious and inflammatory complications

Chronic Granulomatous Disease is the most commonly encountered immunodeficiency involving the phagocyte, and is characterized by repeated infections with bacterial and fungal pathogens, as well as the formation of granulomas in tissue. The disease is the result of a disorder of the NADPH oxidase system, culminating in an inability of the phagocyte to generate superoxide, leading to the defective killing of pathogenic organisms. This can lead to infections with Staphylococcus aureus, Psedomonas species, Nocardia species, and fungi (such as Aspergillus species and Candida albicans). Involvement of vital or large organs can contribute to morbidity and/or mortality in the affected patients. Major advances have occurred in the diagnosis and treatment of this disease, with the potential for gene therapy or stem cell transplantation looming on the horizon.

Flow cytometric investigation of neutrophil oxidative burst and apoptosis in physiological and pathological situations

Flow cytometric analysis provides a rapid screen for abnormalities of polymorphonuclear neutrophils (PMN) function and reflect their behavior in vivo more accurately. This review summarizes the major fluorescent probes used to study PMN oxidative burst and apoptosis using flow cytometry (FCM). We also provide examples of FCM studies in physiological and pathological situations, illustrating the advantages of FCM for assessment of PMN oxidative burst and PMN apoptosis. These data point to the role of FCM in detecting primary immunodeficiencies such as IRAK4 deficiency and support the use of the assessment of the PMN oxidative burst for routine testing in patients with bacterial infections. We also demonstrate the utility of whole-blood analysis using FCM for a better understanding of PMN functionality, i.e., tuning PMN responses to inflammatory stimuli. Finally, FCM permits a simultaneous analysis of phenotypic, functional and morphometric parameters assessing whole-blood PMN apoptosis, in particular in response to Toll-like receptor agonists and during simian immunodeficiency virus infection.

Automation and validation of a rapid method to assess neutrophil and monocyte activation by routine fluorescence flow cytometry in vitro

The aim of the present study was to design an automated-gating hematology fluorescence flow cytometry methodology permitting the assessment of neutrophil and monocyte activation in EDTA-anticoagulated whole blood based on cell granularity, lipid membrane components, cell shape and volume, and total cell nucleic acid (NA) compounds. For particularly monitoring the proper functioning of patients' innate immune system as the first line defense against microbial invaders, the suitable test system should be rapid, simple, reliable by yielding reproducible results. It must be validated against established methods, and it must prove to work in selected clinical settings, e.g. in intensive care unit (ICU) environments. The adaptation of a routine hematology cell analyser utilizing fluorescence flow cytometry resulted in a potentially useful system for all requirements. It proved to detect in real-time and in a reliable and reproducible way the main cellular response reactions of neutrophils and monocytes during externally stimulated immune defense. Validation was successful when comparing it to established methods. The quantified activation effects were dose dependent from the applied activating agents. Cellular response kinetics could be measured and described and showed to be in line with the prevailing cell response models. Upon applying the test method to a healthy population of volunteers and a first cohort of ICU patients with and without evident immune depression, the test revealed excellent cellular responses to external activating cytotoxic stimuli (lipopolysaccharide; LPS) for the control group, slightly weaker response from ICU patients without immune depression and no response from patients with evident immune depression.We conclude that routine hematology fluorescence flow cytometry can accurately and reproducibly measure different activation steps of monocytes and polymorphonuclear neutrophilic granulocytes to defined external stimuli. This may potentially be applied as a STAT (Latin statim = immediately) and routine screening and surveillance method for inflammatory diseases.

DCFH2 interactions with hydroxyl radicals and other oxidants--influence of organic solvents

The oxidation of 2',7'-dichlorofluorescin (DCFH(2)) is widely used as a measure to detect the generation of reactive oxygen species (ROS) and to analyze oxidative stress. Other factors beside commonly known radicals may influence the results of such measurements. Therefore, the effects of H(2)O(2), KMnO(4,) decomposition products of AAPH, ethanol and DMSO, antioxidants like ascorbic acid, different ferrous ion chelates, and heme-containing proteins like cytochrome c, myoglobin, hemoglobin, and horseradish-peroxidase were comparatively analyzed with respect to their impact on DCFH(2) oxidation. The study evaluates the effects of various oxidants with different oxidative potentials regarding their ability to induce DCF-fluorescence. Furthermore, we analyzed the inhibitory effect of organic solvents like ethanol or DMSO on the oxidation of DCFH(2) by hydroxyl radicals. The results of our study indicate that the potential of an oxidant does not always correlate with its efficiency to generate DCF-fluorescence.

Mutations of chronic granulomatous disease in Turkish families

BACKGROUND

Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by impairment of intracellular microbicidal activity of phagocytes. Mutations in one of four known NADPH-oxidase components preclude generation of superoxide and related antimicrobial oxidants, leading to the phenotype of CGD. Defects in gp91-phox, encoded by CYBB, lead to X-linked CGD and have been reported to be responsible for approximately 70% of all CGD cases. The aim of this study was to identify the CGD mutations in a group of Turkish CGD patients and to evaluate the predominance of CGD mutations as X-linked or autosomal recessive (AR) within the Turkish CGD families with known mutations.

MATERIALS AND METHODS

Two Turkish CGD families were included in the study, and mutations were identified by sequence analysis of DNA and RNA from peripheral blood in the patients. Before mutation analysis, subgroup analysis of patients was made by flow cytometry with antibodies against NADPH oxidase components and with DHR-123 oxidase activity assay. For comparison, we included previously reported results from four other Turkish CGD families.

RESULTS

Two different mutations were identified, one of them a novel mutation g.700G>T located in exon 7 of CYBB, and the other a hot-spot mutation located in exon 2 of the NCF1 gene. These mutations were detected in three patients from two Turkish families.

CONCLUSIONS

Until now, we have altogether identified mutations in six Turkish CGD families. In this limited number of families our results show AR-CGD in two-thirds of the Turkish families investigated, in contrast to previous reports in the literature. This is probably due to the high rate of consanguineous marriages in Turkey. Consanguineous parents were found in 75% of the families with AR-CGD patients, which favours homozygous deficiencies.

Skewing of X-chromosome inactivation in three generations of carriers with X-linked chronic granulomatous disease within one family

BACKGROUND

Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by impairment of intracellular microbicidal activity of phagocytes. Mutations in one of the four known NADPH-oxidase components preclude generation of superoxide and related antimicrobial oxidants, leading to the phenotype of CGD. Defects in gp91-phox, encoded by CYBB, lead to X-linked CGD, responsible for approximately 70% of all CGD cases. The aim of the study was to evaluate the hypothesis that age-related skewing of X-chromosome inactivation, as described in several CGD families, is caused by preferential survival of bone marrow clones with an inactive NADPH oxidase.

MATERIALS AND METHODS

We studied the neutrophils from three patients and four carriers in three generations of a Turkish family with X-linked CGD. Carrier detection was carried out by the dihydrorhodamine (DHR)-1,2,3 assay, which measures on a per-cell basis the NADPH oxidase-dependent oxidation of DHR by phagocytes. The X-chromosome inactivation pattern was determined with the HUMARA assay in DNA from leucocytes as well as in DNA from a buccal smear of the four carriers.

RESULTS

The three patients were identified by a negative DHR test, and the mutation in their CYBB gene was characterized by DNA sequencing. Moreover, we found an age-related degree of skewing of X-chromosome inactivation in the leucocytes of the four X-CGD carriers, both at the protein level (NADPH oxidase activity) and at the DNA level (HUMARA assay). However, similar skewing of X-chromosome inactivation was found in the buccal DNA from these women.

CONCLUSIONS

These novel findings indicate that the age-related degree of skewing was probably a chance finding, not related to preferential survival of NADPH oxidase-deficient precursor cells, because this enzyme is not expressed in (buccal) epithelial cells.

Assessment of neutrophil activation in whole blood by flow cytometry

Flow cytometry methods currently used for measuring neutrophil activation involve sample manipulation, which may result in cellular depletion and artifactual activation. To design a new methodology for measurement of neutrophil activation with minimal sample manipulation. Oxidative burst and CD 11b neutrophil expression were simultaneously assessed by a new no-lyse no-wash technique and a standard lyse-method in 10 pediatric patients with recurrent infections and two patients with chronic granulomatous disease (CGD). The new technique was based on nucleic acid staining to discriminate erythrocytes and debris without requiring physical separation. Both methods served equally to confirm or eliminate the diagnosis of CGD and leukocyte adhesion deficiency type 1. The values of baseline CD11b and oxidative burst obtained using the lysis method were significantly higher than those obtained by the no-lyse no-wash method. After activation, the lysis method resulted in higher neutrophil depletion (41%vs. 19%, P = 0.03). When compared with standard methods, neutrophil activation assessment by a no-lyse no-wash method resulted in lower neutrophil depletion and differences in oxidative burst and CD11b neutrophil values.

Iodide excess induces apoptosis in thyroid cells through a p53-independent mechanism involving oxidative stress

Thyroid toxicity of iodide excess has been demonstrated in animals fed with an iodide-rich diet; in vitro iodide is cytotoxic, inhibits cell growth, and induces morphological changes in thyroid cells of some species. In this study, we investigated the effect of iodide excess in an immortalized thyroid cell line (TAD-2) in primary cultures of human thyroid cells and in cells of nonthyroid origin. Iodide displayed a dose-dependent cytotoxicity in both TAD-2 and primary thyroid cells, although at different concentrations, whereas it had no effect on cells of nonthyroid origin. Thyroid cells treated with iodide excess underwent apoptosis, as evidenced by morphological changes, plasma membrane phosphatidylserine exposure, and DNA fragmentation. Apoptosis was unaffected by protein synthesis inhibition, whereas inhibition of peroxidase enzymatic activity by propylthiouracil completely blocked iodide cytotoxicity. During KI treatment, reactive oxygen species were produced, and lipid peroxide levels increased markedly. Inhibition of endogenous p53 activity did not affect the sensitivity of TAD-2 cells to iodide, and Western blot analysis demonstrated that p53, Bcl-2, Bcl-XL, and Bax protein expression did not change when cells were treated with iodide. These data indicate that excess molecular iodide, generated by oxidation of ionic iodine by endogenous peroxidases, induces apoptosis in thyroid cells through a mechanism involving generation of free radicals. This type of apoptosis is p53 independent, does not require protein synthesis, and is not induced by modulation of Bcl-2, Bcl-XL, or Bax protein expression.

The use of flow cytometry to measure neutrophil function

Neutrophils are important professional phagocytic cells that provide the host with a first line of defense against acute bacterial and fungal diseases and recurrent, severe or unusual infections are associated with inherited defects of neutrophil function. Furthermore, abundant evidence links inappropriate neutrophil-mediated tissue damage to the pathogenesis of conditions such as acute respiratory distress syndrome, septicemia with multiorgan failure, ischemia-reperfusion injury and rheumatoid arthritis. Flow cytometry has been increasingly used to evaluate the functional capabilities of neutrophils. In this review, we discuss the use of flow cytometry to assess neutrophil functional responses including calcium mobilization, F-actin assembly, adhesion, aggregation, degranulation, phagocytosis and reactive oxygen species (ROS) production. The use of flow cytometry to identify neutrophil priming is also discussed. The advantage of flow cytometry is that the majority of neutrophil functions can be measured using a small volume of whole blood that reduces artifactual changes in function caused by purification procedures. The advent of numerous new fluorochromes and multiparametric analysis allows the simultaneous measurement of several neutrophil functions in the same population of cells. Flow cytometric analysis provides a rapid screen for abnormalities of neutrophil function and reflects more accurately their behavior in vivo.

Requirement of nuclear factor kappaB for the constitutive expression of nitric oxide synthase-2 and cyclooxygenase-2 in rat trophoblasts

Recently isolated trophoblasts express nitric oxide synthase 2 (NOS-2) and cyclooxygenase 2 (COX-2), decreasing the levels of the corresponding mRNAs when the cells were maintained in culture. The sustained expression of COX-2 and NOS-2 in trophoblasts was dependent on the activation of nuclear factor kappaB (NF-kappaB) since proteasome inhibitors and antioxidants that abrogated NF-kappaB activity suppressed the induction of both genes. The time-dependent fall of the mRNA levels of NOS-2 and COX-2 paralleled the inhibition of NF-kappaB, determined by electrophoretic mobility shift assays, and the increase of the IkappaBalpha and IkappaBbeta inhibitory proteins. Isolated trophoblasts synthesized reactive oxygen intermediates (ROI), a process impaired after culturing the cells, and that might be involved in the NF-kappaB activation process. Moreover, treatment of recently isolated cells with ROI scavengers suppressed the expression of COX-2 and NOS-2. Challenge of trophoblasts with interleukin-1beta up-regulated the expression of both proteins, an effect that was potentiated by lipopolysaccharide. These results indicate that the physiological expression of NOS-2 and COX-2 in trophoblasts involves a sustained activation of NF-kappaB which inhibition abrogates the inducibility of both genes.

Reactive oxygen species as mediators of photoreceptor apoptosis in vitro

Retinitis pigmentosa is a heterogeneous group of retinal degenerations characterized by a progressive loss of photoreceptors through the process of apoptosis. The apoptotic cell death of photoreceptors appears to represent a final common pathway in the pathology of retinitis pigmentosa. Previous studies have reported the ability of antioxidants to ameliorate light-induced retinal degeneration, suggesting a role for oxidative stress in photoreceptor cell death. This study demonstrates an early and sustained increase in intracellular reactive oxygen species accompanied by a rapid depletion of intracellular glutathione in an in vitro model of photoreceptor apoptosis. These early changes in the cellular redox state precede disruption of mitochondrial transmembrane potential, nuclear condensation, DNA nicking, and cell shrinkage, all of which are well-characterized events of apoptotic cell death. The ability of zinc chloride and pyrrolidine dithiocarbamate, two established antioxidants, to inhibit photoreceptor apoptosis through the scavenging of intracellular reactive oxygen species establishes a role for reactive oxygen species as possible mediators of in vitro photoreceptor apoptosis. This study provides a molecular basis for the inhibition of photoreceptor apoptosis by antioxidants.

U-101033E (2,4-diaminopyrrolopyrimidine), a potent inhibitor of membrane lipid peroxidation as assessed by the production of 4-hydroxynonenal, malondialdehyde, and 4-hydroxynonenal--protein adducts

4-Hydroxy-2-nonenal (4-HNE) and malondialdehyde (MDA) are major lipid peroxidation products generated by free radical attack on membranes and appear to contribute to the cytotoxic effects of oxidative stress by a mechanism involving adduct formation with cellular proteins. In the present studies, we investigated the relationship between lipid peroxidation and eventual inactivation of plasma membrane proteins using a model system consisting of purified red blood cell membranes and Fe2+/EDTA. Using this system, we also analyzed the ability of a novel antioxidant, U-101033E (2,4-diaminopyrrolopyrimidine), to inhibit lipid peroxidation and associated protein damage. Our results demonstrated that significant levels of MDA and 4-HNE are generated in this model system, and that both aldehydes are capable of cross-linking membrane proteins. In addition, we used a monoclonal antibody to demonstrate the presence of 4-HNE-protein adducts in this system. The generation of 4-HNE-protein adducts closely paralleled the time course of lipid peroxidation and membrane protein cross-linking, suggesting that 4-HNE may contribute to membrane protein cross-linking. Analysis of U-101033E in this system showed that this antioxidant inhibited lipid peroxidation, prevented the appearance of 4-HNE-protein adducts, and strongly reduced membrane protein cross-linking, with an EC50 of 0.5 microM. We also show that these antioxidant effects were not due to the scavenging of superoxide anion. Thus, these studies demonstrate the potential usefulness of U-101033E for treating certain disease processes where lipid peroxidation plays a role in disease pathogenesis.

Flow cytometric determination of oxidative burst activity of equine peripheral blood and bronchoalveolar lavage-derived leucocytes

Flow cytometric techniques were developed for the evaluation of oxidative burst activity in equine peripheral blood neutrophils and lymphocytes, as well as bronchoalveolar lavage derived pulmonary alveolar macrophages and lymphocytes. The oxidation of dichlorofluorescin was measured by the increased fluorescence of cells stimulated with phorbol myristate acetate or a variety of other stimulants. Flow cytometry was a suitable method for the evaluation of the intracellular oxidation in all cell populations evaluated. Analysis was rapid and cell separation before analysis was not required. Heterogenous cell populations with differing responsiveness to phorbol myristate acetate stimulated oxidative burst were identified in peripheral blood neutrophil and alveolar macrophage populations. The current study characterizes flow cytometric techniques for the evaluation of oxidative burst activity in equine peripheral blood and bronchoalveolar lavage-derived leucocytes.

Comparative study of neutrophil activation by chemiluminescence and flow cytometry

Neutrophil activation by phorbol 12-myristate 13-acetate (PMA) and zymosan was assessed by luminol-dependent chemiluminescence (CL) in a novel microtiter plate format and by flow cytometry (FC) based on the oxidation of dihydrorhodamine 123. The results of this comparison demonstrated striking differences in kinetic parameters between these two techniques for neutrophil activation by PMA and zymosan. PMA activation, as determined by FC, was found to be an all-or-none phenomenon in that below a critical concentration of PMA, few cells were positive. Above this concentration, almost all cells were positive; however, the fluorescence intensity of positive cells increased with an increasing PMA concentration until a plateau (maximal) level was reached. In contrast, increasing zymosan concentrations resulted in proportionate increases in the percentage of positive cells until close to 100% of cells were positive. However, the fluorescence intensity of positive cells remained about the same. CL activity increased proportionately with either PMA or zymosan concentration until a maximal level was achieved. The concentration of PMA required for half-maximal activity was about 10-fold higher for FC than for CL, whereas the analogous concentration of zymosan was about 30-fold higher for CL than for FC. In addition, opsonization had only a small negative effect on the ability of zymosan to activate neutrophils, as determined by FC, whereas it had a very large enhancing effect when determined by CL. The differences in kinetic parameters of activation suggest differential sensitivity to particulate (zymosan) versus soluble (PMA) stimulants for FC and CL.

Lupus erythematosus-like oral mucosal and skin lesions in a carrier of chronic granulomatous disease. Chronic granulomatous disease carrier genodermatosis

We present a case of a young female patient who for 8 years was believed to have discoid lupus erythematosus of the skin and oral mucosae. Only after her infant son had a near-fatal pulmonary infection was the diagnosis of chronic granulomatous disease made and her lupus erythematosus-like mucocutaneous lesions recognized as manifestations of her carrier status for chronic granulomatous disease. The purpose of this report is to raise awareness of and better characterize the mucocutaneous manifestations of carriers of chronic granulomatous disease. Early identification of carriers permits genetic counseling and prenatal diagnosis and forewarns pediatricians so that they can provide better care for affected infants.

Rapid whole-blood flow cytometry assay for diagnosis of chronic granulomatous disease

Chronic granulomatous disease (CGD) is characterized by defective killing of intracellular microorganisms due to mutations in one of the four known components of the NADPH oxidase system. This system is responsible for the generation of superoxide and related antimicrobial oxidants. Diagnosis of CGD requires the demonstration of an abnormal oxidase system in the leukocytes of affected patients. Recently, several flow cytometry-based procedures which measure various reactive oxygen intermediates generated by the NADPH oxidase system have been developed. Most of the procedures developed to date require time-consuming granulocyte isolation, washing, and counting procedures, or they lack sensitivity. We have modified an existing procedure such that cell labelling and stimulation are performed directly in whole blood. Optimization of this procedure and its use in the diagnosis of patients with CGD or X-linked carriers are presented.

Flow cytometric analysis of natural killer cell function as a clinical assay

The 51Cr release assay has been the method of choice in analyzing natural killer cell (NK) function. Previous FCM cytotoxicity assays of NK activity have had numerous disadvantages that discouraged clinicians from attempting to evaluate NK function by flow cytometry. We demonstrate the effectiveness of using PKH-26, a stable membrane dye, to label the K562 target cells and propidium iodide intercalation into killed target cell DNA to determine the percentage of target cells killed by effector NK cells from the peripheral blood or bone marrow. This method compares favorably with the 51Cr release assay and is quicker and easier to perform. The percentage of cytotoxicity of NK cells (CD3- CD56+ and/or CD16+) from 10 normal subjects and 10 HIV-infected children are reported to demonstrate the feasibility of studying NK function in clinical populations by FCM. The potentiation of cytolysis by alpha-interferon and interleukin 2 in vitro was also compared between these two study groups. In addition, a patient whose leukemic blasts expressed CD56+ was also studied for NK activity using this flow cytometric assay. The benefits of using this flow cytometric approach to clinically assess NK function are discussed.