Béatrice Descamps-Latscha

Neutrophils: molecules, functions and pathophysiological aspects.

I. NEUTROPHIL MOLECULES AND FUNCTIONS I.A. ADHESION AND MIGRATION I.A.1. Traffic and margination I.A.2. Adhesion to the Endothelial Wall Rolling and Tethering Neutrophil Priming During Rolling Firm Adhesion and Spreading I.A.3 Extravasation and Diapedesis Toward Inflammatory Stimuli Transendothelial Migration Migration Within Interstitial Tissues Signaling by Chemoattractants Transepithelial Migration I.B. PHAGOCYTOSIS, DEGRANULATION AND BACTERIA KILLING I.B.1. Phagocytosis I.B.2. Degranulation Granule Biogenesis Mechanisms of Degranulation I.B.3. Microbicidal Molecules NADPH-Derived Oxidants The H2O2-Myeloperoxidase System Nitric Oxide-Synthase-Derived Reactive Nitrogen Intermediates Granule Proteins Antimicrobial Proteins Proteases I.C. CYTOKINE SYNTHESIS I.C.1. TNF-a as a Proinflammatory Cytokine I.C.2. IL-1 and IL-1 Receptor Antagonist (IL-1-Ra) I.C.3. IL-8 as a Prototype of Chemokines I.C.4. Modulation of Cytokine Expression by Neutrophils IFN-g IL-10 IL-4 and IL-13 I.C.5. Molecular Regulation of Cytokine Production I.D. APOPTOSIS AND RESOLUTION OF ACUTE INFLAMMATION I.D.1. Progressive Decrease of Neutrophil Recruitment I.D.2. Apoptosis in Resolution of Inflammation II. NEUTROPHILS IN PATHOLOGY II.A. Bacterial Infection II.B. Tissue Injury-Induced Inflammation: IschemiaReperfusion Injury II.C. Crystal-Induced Inflammation II.D. Complement-Induced Inflammation and Oxidative Stress: Hemodialysis II.E. Immune Complex-Induced Inflammation: Antibody-Mediated Glomerunephritis II.F. Cytokine-Induced Inflammation: Rheumatoid Arthritis II.G. Antineutrophil Cytoplasmic Antibodies and Vasculitis: Autoimmunity Against Neutrophil Components II.H. Genetic Disorders of Neutrophil Regulations: Hereditary Periodic Fever Syndromes II.I. Cystic Fibrosis: The Paradox of an Exacerbation of Neutrophil-Mediated Tissue Damage and a Concomitant Persistence of Infection CONCLUSION

Iron Therapy, Advanced Oxidation Protein Products, and Carotid Artery Intima-Media Thickness in End-Stage Renal Disease

Background—Increased common carotid artery intima-media thickness (CCA-IMT) is a marker of early atherosclerosis. Low-grade inflammation is associated with the pathogenesis of atherosclerosis. Low-grade inflammation and increased CCA-IMT are observed in end-stage renal disease (ESRD). Oxidative stress is involved in uremia-related inflammation. Advanced oxidation protein products (AOPP) are markers of oxidant-mediated protein damage in ESRD. Intravenous iron given to patients on hemodialysis (HD) might induce oxidative stress. We investigated the relationships between AOPP, iron therapy, and CCA-IMT in stable HD patients. Methods and Results—Plasma AOPP and blood chemistry, including iron status, were analyzed in a cohort of 79 ESRD patients on HD. Measurements of CCA-IMT and CCA diameter, as assessed by B-mode ultrasonography, were obtained in 60 patients. AOPP levels were elevated in ESRD patients, and in univariate (r =0.42, P <0.0001) and multivariate analyses (r =0.38, P <0.001), they correlated with serum ferritin and with the intravenous iron dose received during the 12 months preceding the study (ferritin, P <0001; AOPP, P <0.01). Univariate and multivariate analyses identified the AOPP concentration as being significantly associated with CCA-IMT (P =0.0197) and CCA wall-to-lumen ratio (r =0.560, P <0.0001). Independently of AOPP concentration, cumulative iron dose was positively related to CCA-IMT (P =0.015) in patients <60 years. Conclusion—In ESRD patients, CCA-IMT and CCA wall-to-lumen ratio were associated with plasma AOPP, serum ferritin, and the annual intravenous iron dose administered. These findings support the concept of a role of oxidative stress in the early atherosclerosis of ESRD patients, which may be increased by the usually recommended doses of intravenous iron.

Establishing the Relationship between Complement Activation and Stimulation of Phagocyte Oxidative Metabolism in Hemodialyzed Patients: A Randomized Prospective Study

The present prospective study was conducted in order to establish the relationship between complement activation and stimulation of phagocyte oxidative metabolism observed in long-term hemodialysis (HD) patients during the early phase of dialysis with cellulosic membranes. Two groups of 10 randomized (HD) patients treated with cellulosic (Cuprophan, CUP) or synthetic polyacrilonitrile (PAN AN-69) membranes were studied. Leukocyte counts, C3a antigen plasma concentration and whole blood basal and stimulated chemiluminescence (CL) production were determined in blood samples drawn from the fistula before dialysis (T0) and from both the afferent and efferent lines of the dialyser at 15 min (T15) and at the end (Tend) of the dialysis session. This study confirms that, coincident with the nadir of leukopenia observed at T15, dialysis with CUP but not PAN membranes induces a marked rise in C3a antigen levels and profound alterations in whole blood CL production consisting of a dramatic increase in basal CL and a significant loss in CL response capacity to stimulating agents. It further demonstrates that a direct relationship exists between the variations in C3a antigen plasma levels and whole blood CL production observed in the CUP group of patients from T0 to T15 (delta 15) of dialysis. This relationship is characterized by a positive correlation between delta 15 C3a and delta 15 basal CL levels in afferent and efferent lines, and a negative correlation between delta 15 C3a and delta 15 CL response capacity values in the efferent but not afferent line. In contrast, no significant correlation with the type of dialysis membrane could be demonstrated between the variations in polymorphonuclear neutrophil counts and C3a antigen levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzodiazepine anethesia in humans modulates the interleukin-1β, tumor necrosis factor-α and interleukin-6 responses of blood monocytes

Abstract The influence of sedative and anxiolytic benzodiazepines on human monocyte function was assessed in 11 patients undergoing anesthesia prior to control endoscopy of the urinary tract. A single i.v. injection of 0.08 mg/kg midazolam induced a marked and delayed inhibition of the lipopolysaccharide-induced production of interleukin-1β, tumor necrosis factor-α and interleukin-6 by monocytes isolated from peripheral blood. Corticosteroids were not responsible for the observed immunosuppression. These studies demonstrate that, when administered in man, benzodiazepines markedly alter the capacity of monocytes to synthetize major mediators of the host inflammatory response.

Inflammation and CFTR: might neutrophils be the key in cystic fibrosis?

The aim of this hypothesis is to provide new insights into the still unclear mechanisms governing airway inflammation in cystic fibrosis. Although the genetic basis of cystic fibrosis as well as the molecular structure of cystic fibrosis transmembrane regulator (CFTR), the mutated protein which causes the disease, have been well defined, a clear relationship between the genetic defect and the pulmonary pathophysiology, especially chronic infections and neutrophil-dominated airway inflammation has not been established. Cystic fibrosis is thus a unique pathological situation in that neutrophils can be depicted as both an antiinfectious and a proinflammatory cell. In cystic fibrosis there is an emerging picture of an imbalance between these two roles with both a reduction in the antiinfectious efficacy and an augmentation of the proinflammatory functions. Better knowledge of fundamental defects in neutrophil function in cystic fibrosis as well as a novel cellular function of CFTR, which will be reviewed, will allow identification of potentially new clinical targets and aid selective therapeutic action aimed at counteracting the lethal neutrophil-induced airway inflammation. The rationale for colchicine therapy is a significant example of a drug which might act both at the molecular levels on CFTR expression in epithelial cells and on neutrophils to mediate antiinflammatory effects. Preliminary results are presented in this issue (Med Inflamm 1999; 8: 13-15).

Priming of Blood Neutrophils in Children with Cystic Fibrosis: Correlation between Functional and Phenotypic Expression of Opsonin Receptors before and after Platelet-Activating Factor Priming

Blood phagocyte opsonin receptor CR1 (CD35) and CR3 (CD11b) functions were examined in cystic fibrosis (CF) patients with endobronchial Staphylococcus aureus or Pseudomonas aeruginosa chronic infection, CF patients without infection, heterozygous, non-CF patients with chronic pulmonary infection, and healthy controls. Circulating and platelet-activating factor (PAF)-primed phagocyte luminol luminescence responses to complement-opsonized zymosan were increased in both groups of infected CF and non-CF children relative to uninfected CF children and healthy control children and adults. The ratio between circulating and PAF-primed phagocyte responses was significantly elevated in all children with CF, and in these, the ratio could serve as an indicator of response to antibiotic treatment. The ratios of circulating and PAF-primed phenotypic expression for CR1, CR3, and FcgammaRIII (CD16), but not FcgammaRII (CD32), correlated with the functional ratios. Phagocyte opsonin receptor response capacity might be used for evaluation of inflammation and infection in CF patients.

A monoclonal antibody against peripheral benzodiazepine receptor activates the human neutrophil NADPH-oxidase

A murine monoclonal antibody, mAb 8523, raised against whole human pro-monocytic U937 cells recognizes an 18 kDa antigen in human neutrophils (PMN), as determined by immunoprecipitation and by immunodetection on Western blots of SDS-PAGE of PMN membrane fractions. That is 18 kDa antigen corresponds to the phagocyte peripheral benzodiazepine receptor (PBZDR) is evidenced by its co-migration with the 18 kDa covalently labeled PBZDR, detected by autoradiography, and their co-modulation upon phorbol-myristate-acetate activation of PMN. Purified mAb 8523 (IgG2b) is able to dose-dependently and specifically stimulate both the basal and the FMLP-induced oxidative burst of intact human PMN, assessed by luminol-amplified chemiluminescence. This property of the first described monoclonal antibody against PBZDR supports the implication of this receptor in NADPH-oxidase activation and consequently in phagocyte-dependent host defense mechanisms.

Myeloperoxidase Promoter Polymorphism −463G Is Associated With More Severe Clinical Expression of Cystic Fibrosis Pulmonary Disease

The severity of cystic fibrosis (CF) pulmonary disease is not directly related to CFTR genotype but depends upon several parameters, including neutrophil-dominated inflammation. Identification of agents modulating inflammation constitutes a relevant goal. Myeloperoxidase (MPO) is involved in both microbicidal and proinflammatory neutrophil activities. The aim of this study was to evaluate whether the −463GA MPO promoter polymorphism is linked to clinical severity of CF-associated pulmonary inflammation. This polymorphism significantly affects the level of MPO gene expression in leukocytes and the G allele is more expressing than the A allele. We show that MPO genotype significantly influences the severity of pulmonary disease in early stages, prior to the development of chronic lung infections, with GG genotype being associated with more severe CF disease. Our findings indicate that the level of MPO gene expression influences the CF pathogenesis, presumably reflecting cellular damage by MPO-generated oxidants or other activity of MPO in airway inflammation.

Characterization of a recombinant proteinase 3, the autoantigen in Wegener's granulomatosis and its reactivity with anti-neutrophil cytoplasmic autoantibodies

Using the baculovirus/insect cells system, we have expressed a recombinant proteinase 3 (PR3) — the neutrophil‐derived serine protease autoantigen in Wegeners granulomatosis — as a glycosylated intracellular and membrane‐associated protein. Ollgosaccharides accounted for the difference in molecular weights between recombinant (34 kDa) and neutrophil‐PR3 (29 kDa). Whereas rabbit‐anti‐PR3 IgG recognized both recombinant and neutrophil‐derived PR3, autoantibodies from Wegener patient sera recognized only neutrophil‐derived PR3. Although oligosaccharides were not involved in PR3 epitope recognition, autoantibodies did not recognize the amino acid primary structure of recombinant PR3. Improper disulfide bond formation and/or lack of post‐translational events in insect cells, may affect the conformation of PR3, precluding its reactivity with sera from WG patients.

Induction of cytokines by dialysis membranes in normal whole blood: a new in vitro assay for evaluating membrane biocompatibility.

We investigated the capacity of cellulose cuprophane (CUP) and synthetic polyacrylonitrile dialysis membranes to induce the production of interleukin 1 (IL-1), interleukin 6 (IL-6), and tumor necrosis factor alpha using an in vitro model in which normal whole blood is incubated directly with calibrated membrane fragments. We found that only CUP membranes significantly increased plasma levels of IL-1, IL-6, and tumor necrosis factor alpha. The participation of lipopolysaccharide was excluded, since its addition to whole blood incubated with CUP led to a synergistic enhancement of IL-1 production, while the addition of polymyxin B had no significant effect. Transfer experiments showed that CUP-pretreated plasma was able to induce cytokine production by autologous monocytes. Inactivation of complement components prior to pretreatment abolished this effect. The participation of complement activation was further revealed by a correlation between cytokine and C5a plasma levels. Lastly, incubation of isolated monocytes with CUP but not with polyacrylonitrile also induced cytokine production, although to a lesser degree. In conclusion, our simple in vitro model can be used to evaluate the biocompatibility of dialysis membranes directly by using whole blood with greater relevance to the in vivo situation than models based on isolated blood components.