Rationale: Tissue Factor (TF) is a transmembrane glycoprotein that canonically functions as the initiator of the coagulation cascade. Increased levels of TF have been associated with inflammatory airway diseases. Since lipopolysaccharide (LPS) is known to elicit and inflammatory response in airway epithelium, we hypothesized that airway epithelial cells release TF when exposed to LPS. Since TF aids in local wound healing, we also hypothesized that inhibition of TF would decrease NHBE growth. The specific aim of this work was to evaluate the effects of LPS exposure on TF production and release from airway epithelia and determine the signaling pathways involved. A secondary aim was to evaluate the effects of TF inhibition on NHBE growth. Methods: Normal human bronchial epithelial cells were grown in submerged cell culture and exposed to LPS as well as several intracellular signaling pathway agonist and inhibitors. Measurements: Tissue Factor mRNA and protein were measured in culture media and cell lysate by reverse-transcriptase polymerize chain reaction and enzyme-linked immunosorbent assay, respectively. Signaling pathways were evaluated using selective agonists and inhibitors. Main results: TF protein levels increased nearly two-fold in cell media after exposure to LPS (p < 0.01). This did not occur in the presence of an MEK/ERK inhibitor (PD98059) or a SMAD inhibitor (SB431542). TF protein levels also increased nearly ten-fold in the presence of TGF-beta (p < 0.05). mRNA of TF and TGF-beta was not altered by LPS or TGF-beta exposure. NHBE grown in the presence of Tissue Factor Pathway Inhibitor grew significantly slower than those grown in standard media (P < 0.05). Conclusions: NHBE release TF when exposed to LPS. This phenomenon is post-translational and may be mediated by an autocrine mechanism involving MEK/ERK signaling that increases TGF-beta which then leads to the release of TF. Our data suggest that this airway epithelium release of TF serves as a local repair function.

Children with life threatening food allergies live with the constant threat of a fatal reaction, and caregivers must always be prepared to treat with an epinephrine auto-injector (EAI). This interpretive phenomenological study explored parents’ perceptions and lived experiences with prescribed EAI use for their child. The purposive sample included 10 parents of five children under 12 years of age, diagnosed with a food allergy and prescribed with an EAI who recently experienced anaphylaxis. Eight main themes emerged: perception of anaphylaxis, life challenges, isolation, anxiety, hesitation, guilt, influence of health care, and lessons learned. Parents described multiple life challenges and feelings of isolation, anxiety and hesitation during a reaction that lead to subsequent guilt. Handling reactions correctly provided parents with confidence to treat subsequent reactions. Witnessing the effects of an EAI and receiving positive feedback from health care providers further strengthened their confidence to quickly and competently intervene in future reactions. / February 2017

Fluvastatin, the HMG-CoA reductase inhibitor known for its role in the treatment of hypercholesterolemia and cardiovascular disease, has more recently been shown to play a role in the immune response. Given the critical role that mast cells play in allergy and inflammatory diseases such as asthma, which effects one third of America’s population, we assessed the effect of fluvastatin on mast cell and basophils function. We demonstrate that fluvastatin downregulated IgE-mediated cytokine production. Additionally, in vivo studies showed that fluvastatin suppressed IgE-mediated anaphylaxis. Interestingly, the effects of fluvastatin showed dependence on genetic background, as C57BL/6 mast cells were sensitive, while 129/Sv mast cells were resistant to fluvastatin. Characterizing the role of fluvastatin on mast cells may prove to be therapeutically important.

This study shows for the first time the effect that L-(+)-lactic acid has on mast cell activation. Lactic acid is a byproduct of anaerobic glycolysis and is associated with inflammatory environments such as wounds, tumors and, asthma. In this study, pre-treatment with lactic acid altered cytokine production by bone marrow-derived mast cells (BMMC). Specifically, lactic acid enhanced cytokine secretion following IgE cross-linking, but decreased IL-33 mediated cytokine production. These effects were altered by genetic background, since C57BL/6 mast cells demonstrated the aforementioned result, but lactic acid had no effect on IgE-mediated cytokine production in 129/SvJ mast cells. The affected cytokines included IL-6, TNF, MCP-1, MIP-1α, IL-13, and VEGF. Lactic acid pretreatment promoted a G0/G1 cell cycle arrest. Investigation into the IL-33 signaling pathway showed lactic acid decreased TAK1 and JNK phosphorylation, while increasing phosphorylated AKT levels. Blocking JNK and TAK1 with a small molecule inhibitor mimicked the effects of lactic acid. Interestingly, lactic acid significantly increased IL-33 mediated VEGF. An in vitro angiogenesis assay confirmed that mast cells were pro-angiogenic in a lactic acid-rich environment. Taken together, these data show that lactic acid impacts mast cell function, possibly promoting a pro-angiogenic, anti-inflammatory phenotype.

TGFβ is involved in many pathological conditions, including autoimmune disorders, cancer, and cardiovascular and allergic diseases. We have previously found that TGFβ can suppress IgE-mediated mast cell activation in human and mouse mast cells in vitro. IL-33 is a recently discovered member of the IL-1 family capable of inducing mast cell responses and enhancing IgE-mediated activation. In this study, we investigated the effects of TGFβ on IL-33-mediated mast cell activation. Bone marrow-derived mast cells cultured in TGFβ -1, -2, or -3 showed reduced IL-33-mediated production of TNF, IL-6, IL-13 and MCP-1, in a concentration-dependent manner. Furthermore, TGFβ also reduced expression of the T1/ST2 receptor as well as IL-33-mediated TAK1 and ERK phosphorylation. TGF-ß1 injection suppressed IL-33-mediated production of systemic inflammatory cytokines in vivo. The role of IL-33 in the pathogenesis of allergic diseases is incompletely understood. These findings, consistent with our previously reported effects of TGFβ on IgE-mediated activation, demonstrate that TGFβ can provide broad and substantial inhibitory signals to activated mast cells.

Through underexpression and overexpression studies, CD23 has been shown to negatively regulate IgE production. To investigate CD23 destabilization and its effects on CD23 shedding and IgE synthesis in vivo, we utilized an anti-CD23 stalk monoclonal (19G5) which has previously been shown to enhance proteolysis of CD23 in vitro. Compared to isotype control-treated mice, mice injected with 19G5 displayed enhanced serum soluble CD23 and IgE. Because 19G5 injection substantially enhanced CD23 shedding, it was useful in investigating the identity of the CD23 sheddase. 19G5 enhanced CD23 shedding in ADAM8-/-, ADAM9-/-ADAM15-/-, and ADAM9-/-ADAM12-/-ADAM15-/- mice, ruling out these ADAMs as candidate CD23 sheddases. Through the use of an ADAM10 inhibitor, we blocked CD23 shedding from murine B cells while increasing CD23 surface levels, and thus we identified ADAM10 as the CD23 sheddase. During the course of the ADAM investigation, we discovered that the 129/SvJ inbred mouse strain carried five amino acid substitutions within its CD23 gene. The mutations resulted in reduced CD23 surface expression and hyper IgE levels in vivo. The hyper IgE phenotype was consistent with a more rapid clearance of Nippostrongylus brasiliensis from the gut of 129/SvJ mice. B cells from 129/SvJ spleens proliferated more rapidly than those from BALB/c after stimulation with IL-4 and CD40 ligand trimer in vitro. However, in vitro IgE levels in supernatants from 129/SvJ B cells were significantly reduced, suggesting that the B cells were no longer responsive to IL-4 in vitro. Although the affinity of the IgE-129/SvJ CD23 interaction was similar to that of the BALB/c, 129/SvJ B cells exhibited a reduced number of IgE binding sites, demonstrating that high levels of CD23 are essential for controlling IgE synthesis. This finding was further confirmed in another disease model, namely the mouse asthma model. Mice overexpressing CD23 displayed suppressed allergic lung inflammation and reduced levels of IgE and Th2 cytokines and chemokines. Overall, the data provide a direct demonstration for CD23's role in regulating IgE production in vivo and suggest that therapies aimed at stabilizing cell surface CD23 would inhibit proteolysis and increase surface expression, and thus would be beneficial in controlling allergic disease.

La première partie de ce travail se centre sur la recherche de tests sanguins (reposant sur les granulocytes) de dépistage, de suivi et d’efficacité thérapeutique dans différentes maladies allergiques. Elle débute par un travail réalisé dans la maladie asthmatique. Elle se poursuit par l’étude du rôle des granulocytes (polynucléaires neutrophiles et/ou polynucléaires éosinophiles et/ou basophiles) dans deux maladies allergiques : l’oesophagite à éosinophiles et les allergies alimentaires. Chez des patients atteints d’oesophagite à éosinophiles, nous avons étudier le profil d’activation des éosinophiles sanguins et de l’œsophage. Nous nous sommes focalisés sur certains marqueurs d’activation de surface (CD66b) et sur certains phosphoépitopes d’intérêt (Ph-STAT1 et Ph-STAT6). Nous avons démontré que les éosinophiles sanguins avaient un profil spécifique dans cette maladie. Enfin, cette première partie s’achève par deux études portant sur les basophiles sanguins dans les allergies alimentaires, plus précisément, dans les allergies aux fruits à coques ; Nous avons développé de nouveaux potentiels tests de dépistage de patients atteints d’allergies alimentaires, d’identification des allergènes responsables ainsi que de potentiels marqueurs d’évaluation d’efficacité de nouvelles thérapeutiques dans les allergies alimentaires par l’utilisation des marqueurs d’activation de surface des basophiles.La deuxième partie se centre principalement sur le rôle des polynucléaires neutrophiles (PNN) du sang et des voies aériennes des patients atteints de mucoviscidose. La mucoviscidose est la maladie génétique autosomique récessive la plus fréquente dans l’Europe du nord. Son pronostic est étroitement lié à l’atteinte pulmonaire, qui se caractérise par des infections à répétition, une obstruction et une inflammation à PNN. Notre équipe a tout d’abord démontré que les PNN sanguins de patients atteints de mucoviscidose présentaient un déficit en glutathion. Nous avons donc réaliser un essai clinique de phase IIa ou, N-acétyl-cystéine (précurseur du glutathion) était donné, à forte dose et par voie orale à des patients atteints de mucoviscidose. Ce traitement par N-acétyl-cystéine pendant douze semaines a permis une correction du déficit des PNN sanguins en glutathion. Cette correction de l’excès de stress oxydatif au sein des PNN a permis une diminution significative du nombre d’exacerbation chez les patients atteints de mucoviscidose. En revanche, possiblement en raison de la courte durée de ce traitement, aucune différence significative ne fut observée au niveau des paramètres de fonction respiratoire, tels que le VEMS. De plus, nous avons démontré que les PNN des voies aériennes des patients atteints de mucoviscidose dysfonctionnaient. En effet, alors qu’il était rapporté dans la littérature que les PNN nécrotiques des voies aériennes larguaient de manière passive l’élastase et la myélopéroxidase, nous avons démontré que les PNN vivants larguaient de manière active ces deux enzymes, dont la présence est en étroite corrélation avec le déclin de la fonction pulmonaire.. Nous avons alors émis l’hypothèse que les PNN, lors de leur migration du sang vers les voies aériennes, s’activaient anormalement. Nous avons donc décider d’étudier leurs cascade d’activations intracellulaire. Nous avons ainsi démontré que les PNN des voies aériennes des patients atteints de mucoviscidose présentaient une régulation positive de la voie mTOR. mTOR étaient possiblement activé par la pléthore d’acides aminés présents dans le poumon mucoviscidosique. mTOR pourrait refléter une possible survie prolongée des PNN des voies aériennes du poumon mucoviscidosique. Ces PNN pourraient aussi secréter de nouvelles protéines, alors même qu’ils sont « conventionnellement » définis comme cellules terminallement différenciées. [...] / Summary of the first part. We hypothesized that granulocytes were not only playing an effector role in atopic diseases, but also a regulatory role. Furthermore, we proposed that granulocytes, due to their rapid activation response, could be used in rapid non-invasive whole blood assays for Allergic Asthma (AA), Food Allergy (FA) and Eosinophillic Esophagitis (EoE), three allergic diseases. We first studied asthma. Then, we explored the profil of activation of blood eosinophils in patients with EoE. We explored some activation surface markers (CD66b) and some intracellular phosphoepitopes of interest (Ph-STAT1 and Ph-STAT6). We then focused our attention on blood basophils in food allergy. We developped a potential blood basophil assay (based on two basophil activation surface markers, CD203c and CD63), which could discriminate a patient with food allergy, which could also identify the offending allergen and, which could monitor the effect of new therapy.Summary of the second part. We focused our attention on the role of the blood and sputum neutrophils in cystic fibrosis (CF). Cystic fibrosis is the most frequent disease in Caucasians. While CF affects all exocrine organs throughout the body, its lung manifestation represents the main cause of morbidity and mortality. We first discovered that blood neutrophils were deficient in glutathion. We therefore started a clinical phase IIa, where N-acetyl-cystein were given orally in high dose to patients with CF for twelve weeks. Thanks to this regimen, the deficit in glutathion in blood PNN disappeared. The number of exacerbations significantly decreased, however, no positive effect were observerd on the lung function. Furthermore, we demonstrated that profound functional and signaling changes readily occur within viable PNN recruited to CF airways, compared to their blood counterparts. For a long time, neutrophil dysfunction in CF airways has been equated with necrosis and passive release of elastase, DNA and, actin. However, we established recently by direct ex vivo analysis of airway neutrophils from CF patients that a large fraction of these cells are viable and appear to actively release these enzymes-containing granules. We also show that neutrophils that entered CF airways have increased phosphorylation of key effectors in the amino acid-regulated mammalian target of rapamycin (mTOR) pathway. An upregulation of the mTOR pathway might reflect an increase of the survival of the neutrophils in the airways. Another common view of peripheral neutrophils is that of terminally differentiated population, with little if any ability to become anabolic. However, we outlined the ability of human neutrophils to modify their transcriptional profile upon migration to the lung in CF. The last part of these thesis is a combination of knowledge that we acquired on the blood basophils in food allergy and on the neutrophils from the airways of patients with CF. We are currently trying to develop an unmet need blood (basophil) test which could discrimate the CF patients with allergic bronchopulmonary aspergillosis. We are also trying to understand the role of airways neutrophils and eosinophils in the pathogenese of these disease.

Doctor of Philosophy / Department of Hospitality Management and Dietetics / Deborah D. Canter / Junehee Kwon / Food allergies affect 1 in 25 school-aged children in the U.S., and Child Nutrition Professionals (CNPs) need more vigilance serving them. To assess CNPs’ knowledge, attitudes about food allergies including barriers to providing food allergy training, as well as current training practices; an online survey was conducted with randomly selected 1,500 CNPs nationwide. The survey instrument was developed based on focus groups, pilot-tested, and sent to the sample via email. About 24% or 340 CNPs completed the survey. Descriptive and inferential statistics including hierarchical and logistic regressions were calculated using SPSS. A majority of respondents currently provide allergen free meals in their districts (n=256). The mean food allergy knowledge score of CNPs was 31.9 (Standard Deviation=3.3) of 39. Respondents scored lowest on recognizing symptoms of food allergic reactions and understanding food allergen-related terminology. Years of managerial experience and previous food allergy training were positively associated with the knowledge scores. Most participants viewed food allergy as an important issue, but they faced challenges fulfilling last-minute allergen-free meal requests and purchasing allergen-free products. Sixty percent (n=200) did not provide any food allergy training. Of those who provided some sorts of training (n=140), the training was provided in groups (n=96), “one-on-one” basis (n=30), or combination of both methods (n=14). The employees were trained annually (n=76), once a year if they worked directly with the students with food allergies (n=52), and/or when they were newly hired (n=33). Lack of time and funding were barriers to providing food allergy training. Previous food allergic reactions and regulatory requirements served as cues to providing food allergy training. Previous food allergy training, knowledge, and self-efficacy were factors differentiating if food allergy training had or had not been provided in past 12 months. Systematic and regular food allergy training may be needed to ensure allergen-free meals are properly prepared. Food allergy training for CNPs to improve knowledge and self-efficacy may increase food allergy training at school food service establishments.

Allergien sind häufige Erkrankungen in vielen industrialisierten Ländern. Ihre Entstehung beruht auf einem komplexen Zusammenspiel von genetischen und umweltassoziierten Einflüssen. Eine Vielzahl möglicher Faktoren ist beschrieben, die das Auftreten von AllerT gien beeinflussen können, etwa das Alter oder das Geschlecht. Es gibt allerdings nur sehr wenige Daten zur Verbreitung allergischer Erkrankungen in der älteren Bevölkerung. Das Ziel der vorliegenden Arbeit ist es, eine Übersicht zur Prävalenz allergischer ErkranT kungen und Sensibilisierungen in einer Stichprobe der 40T79Tjährigen Bevölkerung Leipzigs zu geben. Hierzu wurden insgesamt 4088 Probanden der zweiten ZwischenausT wertung (1. November 2011 bis 12. Juni 2013) der LIFETStudie untersucht. LIFE (Leipziger Forschungskomplex für Zivilisationserkrankungen) ist eine Kohortenstudie zur Erfassung von lebensstilT und umweltassoziierten Erkrankungen, beispielsweise Allergien, und mögT lichen Einflussfaktoren. In der vorliegenden Arbeit werden allergische Erkrankungen (alT lergische Rhinitis, Asthma bronchiale, atopisches Ekzem, Urtikaria, Anaphylaxie, NahT rungsmittelT und Insektengiftallergien) anhand eines AllergieTInterviews erfragt; SensibiliT sierungen werden mittels IgETDiagnostik für InhalationsT (SX1T) und NahrungsmittelallerT gene (FX5TScreeningtest) bzw. mittels Hautpricktest (Birke, Wiesenlieschgras, Beifuß, Dermatophagoides pteronyssinus, Alternaria alternata und Ambrosia) erfasst, weiterhin wird das GesamtTIgE bestimmt. Als mögliche Einflussfaktoren werden das Geschlecht, das Alter, der sozioökonomische Status und die allergologische Familienanamnese unterT sucht, hierzu werden neben den Prävalenzen auch OddsTRatios berechnet. Allergien sind häufige Erkrankungen in vielen industrialisierten Ländern. Ihre Entstehung beruht auf einem komplexen Zusammenspiel von genetischen und umweltassoziierten Einflüssen. Eine Vielzahl möglicher Faktoren ist beschrieben, die das Auftreten von Allergien beeinflussen können, etwa das Alter oder das Geschlecht. Es gibt allerdings nur sehr wenige Daten zur Verbreitung allergischer Erkrankungen in der älteren Bevölkerung. Das Ziel der vorliegenden Arbeit ist es, eine Übersicht zur Prävalenz allergischer Erkrankungen und Sensibilisierungen in einer Stichprobe der 40-79-jährigen Bevölkerung Leipzigs zu geben. Hierzu wurden insgesamt 4088 Probanden der zweiten Zwischenauswertung (1. November 2011 bis 12. Juni 2013) der LIFE-Studie untersucht. LIFE (Leipziger Forschungskomplex für Zivilisationserkrankungen) ist eine Kohortenstudie zur Erfassung von lebensstil- und umweltassoziierten Erkrankungen, beispielsweise Allergien, und möglichen Einflussfaktoren. In der vorliegenden Arbeit werden allergische Erkrankungen (allergische Rhinitis, Asthma bronchiale, atopisches Ekzem, Urtikaria, Anaphylaxie, Nahrungsmittel- und Insektengiftallergien) anhand eines Allergie-Interviews erfragt; Sensibilisierungen werden mittels IgE-Diagnostik für Inhalations- (SX1-) und Nahrungsmittelallergene (FX5-Screeningtest) bzw. mittels Hautpricktest (Birke, Wiesenlieschgras, Beifuß, Dermatophagoides pteronyssinus, Alternaria alternata und Ambrosia) erfasst, weiterhin wird das Gesamt-IgE bestimmt. Als mögliche Einflussfaktoren werden das Geschlecht, das Alter, der sozioökonomische Status und die allergologische Familienanamnese untersucht, hierzu werden neben den Prävalenzen auch Odds-Ratios berechnet. Insgesamt zeigt sich, dass allergische Erkrankungen und Sensibilisierungen in der untersuchten Stichprobe häufig sind. Die Einflussfaktoren zeigen unterschiedliche Effekte für das Risiko einer Allergie. Beispielsweise geht eine positive allergologische Familienanamnese mit einem erhöhten Risiko einher. Die möglichen Ursachen für Prävalenzunterschiede bei den allergischen Erkrankungen im Vergleich mit der Literatur und das Verhalten der Einflussfaktoren werden, ebenso wie die bestehenden Limitationen von LIFE, kritisch diskutiert. In der vorliegenden Arbeit wird erstmalig der Status quo von allergischen Erkrankungen in einer Probandengruppe der älteren Leipziger Bevölkerung gezeigt. Allergien sind bei den älteren Teilnehmern weniger häufig als bei den jüngeren, aber immer noch weit verbreitet. Weitere Untersuchungen sind notwendig, um mögliche Prävalenzänderungen zu dokumentieren und weitere Einflussfaktoren zu untersuchen. LIFE und seine geplanten Nachuntersuchungen bieten hierfür passende Möglichkeiten.

Les maladies allergiques sont en constante augmentation tant en prévalence qu’en gravité. Les éosinophiles sont fortement impliqués dans le dommage et le dysfonctionnement tissulaire et participent à l’entretien de l’inflammation allergique. Différentes cellules de l’immunité innée sont impliquées dans le contrôle de la réaction allergique. Parmi elles, les cellules NK, connues essentiellement pour leurs fonctions anti-tumorales et anti-microbiennes, pourraient réguler différents aspects de la réaction. Dans le sang périphérique de patients asthmatiques, les cellules NK présentent des capacités cytotoxiques accrues, ainsi qu’une prédominance de cellules NK2 comparativement à la prédominance de cellules NK1 chez les sujets non allergiques. Chez des patients atteints de dermatite atopique, le nombre et la cytotoxicité des cellules NK périphériques sont diminués, ainsi que leur capacité à produire de l’IFN-g. De plus, le dialogue entre les cellules NK et les cellules dendritiques est moins efficace chez le sujet asthmatique, menant ainsi à une capacité réduite de production d’IFN-g par les cellules NK. Dans des modèles murins d’inflammation pulmonaire, la déplétion en cellules NK par l’anti-NK1.1 ou l’anti-ASGM1 avant l’immunisation inhibe l’éosinophilie pulmonaire, l’infiltrat des LT CD3+ et l’augmentation des taux d’IL-4, IL-5 et IL-12 dans le LBA. Néanmoins, la déplétion avec l’anti-ASGM1 après l’établissement de l’inflammation éosinophilique retarde sa résolution, suggérant un rôle double des cellules NK dans l’inflammation allergique. Le recrutement et la fonction des cellules NK humaines dans l’allergie par le biais de l’analyse in vitro du rôle de CCL18 sur les cellules NK a été analysé. Cette chimiokine est préférentiellement produite au niveau du poumon et possède une double fonction dans la pathologie allergique puisqu’elle recrute les LTh2, mais également les LT reg et génère des DCs tolérogènes capables d’induire des LT reg, uniquement chez des donneurs non allergiques. Nous avons évalué la réponse des cellules NK de sujets allergiques vis-à-vis de CCL18 et l’avons comparée à celle de cellules NK provenant de sujets non allergiques. Nos travaux ont montré que CCL18 attire in vitro les cellules NK de sujets non allergiques et induit leur cytotoxicité, de façon dépendante des protéines G. Par contre, les cellules NK de sujets allergiques ne répondent pas au CCL18. La deuxième partie du travail s’est basée sur l’hypothèse d’un dialogue entre les cellules NK et les éosinophiles qui modifierait leurs fonctions respectives. Des cellules NK et des éosinophiles autologues ont été cocultivés pendant 3 et 12h, à différents ratios. Nous avons montré que les cellules NK activent directement les éosinophiles comme en témoignent l’augmentation de la libération de l’ECP, l’EDN, et de l’expression du CD63, du CD69 et la diminution de l’expression du CD62L sur les éosinophiles. De plus, les cellules NK induisent l’apoptose et la mortalité des éosinophiles dès la première heure de coculture. Cependant l’apoptose et la mortalité des cellules NK ne sont pas modifiées. La fixation des cellules NK empêche presque totalement l’activation et l’apoptose des éosinophiles, suggérant l’implication de molécules de surface et peut être de facteurs solubles. Les interactions entre molécules de surface restent à déterminer, et l’IFN-g et le TGF-β ne sont pas impliqués. Cependant, les voies de signalisation p38MAPkinase, ERK, JNK et PI3kinase interviennent dans l’activation des éosinophiles. La voie mitochondriale et ROS sont impliquées dans l’apoptose des éosinophiles induite par les cellules NK.En résumé, ces travaux ont permis de montrer que les cellules NK de sujets allergiques présentent un dysfonctionnement dans la réponse vis-à-vis de CCL18 comparativement aux sujets non-allergiques. De plus, nos résultats suggèrent que les cellules NK pourraient réguler l’inflammation à éosinophiles en induisant leur activation et/ou leur apoptose. / Allergic diseases are steadily increasing both in prevalence and severity. Known physiopathological mechanisms involve the induction of a Th2 response by dendritic cells, leading to IgE production and inflammation, in particular linked to the recruitment of eosinophils. Eosinophils are heavily involved in injury and tissue dysfunction and contribute to the maintenance of inflammation. Different cells of innate immunity were shown to be involved in the control of allergic reaction. Among them, (NK) cells, primarily known for their anti-tumor and anti-microbial functions, may regulate different aspects of allergic reaction as suggested by studies in humans or mice. In the peripheral blood of patients with asthma, NK cells exhibit increased cytotoxic capacity, and a predominance of NK2 cells compared to the prevalence of NK1 cells in non-allergic subjects. In patients with atopic dermatitis, the number and cytotoxicity of peripheral NK cells are reduced, as well as their ability to produce IFN-g. Moreover, the dialogue between NK cells and dendritic cells is less effective in asthmatic patients, leading to a reduced capacity of IFN-g production by NK cells. In murine models of pulmonary inflammation, depletion of NK cells by anti-NK1.1 or anti-ASGM1 before immunization inhibits pulmonary eosinophilia, the infiltration of CD3+ T cells and increased levels of IL-4, IL-5 and IL-12 in the bronchoalveolar lavage. However, depletion with anti-ASGM1 after the establishment of eosinophilic inflammation delays its resolution, suggesting a dual role of NK cells in allergic inflammation.We studied the recruitment and function of human NK cells in allergy through in vitro analysis of the role of CCL18 on NK cells. This chemokine is preferentially produced in the lungs and has a dual role in allergic diseases since it recruits Th2 cells but also regulatory T cells and generates tolerogenic DCs capable of inducing regulatory T cells only from non-allergic donors. We evaluated the response of NK cells in allergic subjects towards CCL18 and compared it to that of NK cells from non-allergic donors. We showed that CCL18 attracts NK cells from non-allergic subjects and induces their cytotoxicity in a G protein dependent pathway. However, NK cells from allergic subjects did not respond to CCL18. This chemokine has no effect on the proliferation of NK cells, but may negatively regulate IFN-g production.The second part of the thesis is based on the hypothesis of a dialogue between NK cells and eosinophils which would modify their respective functions. NK cells and autologous eosinophils were cocultured during 3 and 12 hours, at different ratios. We showed that NK cells directly activate eosinophils as evidenced by the increased release of ECP, eosinophil derived neurotoxin EDN, and the expression of CD63, CD69, and reduced expression of CD62L on living eosinophils. In addition, coculture with NK cells induced apoptosis and mortality of eosinophils in the first hours of coculture. However, apoptosis and death of NK cells were not changed. Fixation of NK cells prevented almost completely the activation and apoptosis of eosinophils, suggesting the involvement of surface molecules, however soluble factors cannot be excluded. These interactions require cell contact, but the molecules involved remain to be determined. Concerning soluble factors, IFN-g and TGF-β are not involved in these mechanisms. However, the signaling pathways p38MAPkinase, ERK, JNK and PI3-kinase are involved in eosinophils activation. Concerning eosinophil apoptosis induced by NK cells, the mitochondrial pathway is more involved than the caspase pathway.In summary, our studies show that NK cells from allergic patients exhibit a defect in their response towards CCL18 compared to non-allergic subjects. In addition, these results suggest that NK cells may regulate eosinophilic inflammation by inducing their activation and / or apoptosis.