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M Jutel

Publications and source records attributed to M Jutel.

At least 19 recordsLinked to original sources
PubMed2006

Highlights in cellular and molecular mechanisms of allergic diseases. XXVth Congress of the European Academy of Allergology and Clinical Immunology in Vienna.

This year, the annual congress of the European Academy of Allergology and Clinical Immunology was held on 10-14 June in Vienna. More than 6,000 delegates, practicing bench or bedside work or both, gathered from over 50 countries throughout the world. Health professionals, basic scientists and fellows in training could choose between a variety of activities in plenary, main, educational and workshop sessions, highlights of the past year, pros and cons, and oral abstract and poster sessions, and met with experts. A total of 1,713 abstracts, 31 symposia, and 54 workshops were presented, ranging from basic science to clinical trials and modern treatment of allergic diseases. Here, we summarize the highlights of cellular and molecular mechanisms of allergic disease.

Allergy and Immunology↗
PubMed2006

Mechanisms of allergen specific immunotherapy--T-cell tolerance and more.

Specific immune suppression and induction of tolerance are essential processes in the regulation and circumvention of immune defence. The balance between allergen-specific T-regulatory (Treg) cells and T helper 2 cells appears to be decisive in the development of allergic and healthy immune response against allergens. Treg cells consistently represent the dominant subset specific for common environmental allergens in healthy individuals. In contrast, there is a high frequency of allergen-specific T helper 2 cells in allergic individuals. A decrease in interleukin (IL)-4, IL-5 and IL-13 production by allergen-specific CD4+ T cells due to the induction of peripheral T cell tolerance is the most essential step in allergen-specific immunotherapy (SIT). Suppressed proliferative and cytokine responses against the major allergens are induced by multiple suppressor factors, such as cytokines like IL-10 and transforming growth factor (TGF)-beta and cell surface molecules like cytotoxic T lymphocyte antigen-4, programmed death-1 and histamine receptor 2. There is considerable rationale for targeting T cells to increase efficacy of SIT. Such novel approaches include the use of modified allergens produced using recombinant DNA technology and adjuvants or additional drugs, which may increase the generation of allergen-specific peripheral tolerance. By the application of the recent knowledge in Treg cells and related mechanisms of peripheral tolerance, more rational and safer approaches are awaiting for the future of prevention and cure of allergic diseases.

Administration, Sublingual↗
PubMed2005

Prevention and treatment of hymenoptera venom allergy: guidelines for clinical practice.

Based on the knowledge of the living conditions and habitat of social Aculeatae a series of recommendations have been formulated which can potentially greatly minimize the risk of field re-sting. After a systemic sting reaction, patients should be referred to an allergy specialist for evaluation of their allergy, and if necessary venom immunotherapy (VIT). An emergency medical kit should be supplied, its use clearly demonstrated and repeatedly practised until perfected. This should be done under the supervision of a doctor or a trained nurse. Epinephrine by intramuscular injection is regarded as the treatment of choice for acute anaphylaxis. H1-antihistamines alone or in combination with corticosteroids may be effective in mild to moderate reactions confined to the skin and may support the value of treatment with epinephrine in full-blown anaphylaxis. Up to 75% of the patients with a history of systemic anaphylactic sting reaction develop systemic symptoms once again when re-stung. Venom immunotherapy is a highly effective treatment for individuals with a history of systemic reaction and who have specific IgE to venom allergens. The efficacy of VIT in yellow jacket venom allergic patients has been demonstrated also by assessing health-related quality of life. If both skin tests and serum venom specific IgE turn negative, VIT may be stopped after 3 years. After VIT lasting 3-5 years, most patients with mild to moderate anaphylactic symptoms remain protected following discontinuation of VIT even with positive skin tests. Longer term or lifelong treatment should be considered in high-risk patients. Because of the small but relevant risk of re-sting reactions, in these patients, emergency kits, including epinephrine auto-injectors, should be discussed with every patient when stopping VIT.

Adult↗
PubMed2005

Histamine in chronic allergic responses.

In addition to its well-characterized effects in the acute inflammatory and allergic responses, histamine has been shown to affect chronic inflammation and regulate several essential events in the immune response. Histamine can selectively recruit the major effector cells into tissue sites and affect their maturation, activation, polarization, and effector functions leading to chronic inflammation. On the other hand histamine acting through its receptor (HR) type 2 positively interferes with the peripheral antigen tolerance induced by T regulatory (Treg) cells in several pathways. Histamine also regulates antigen-specific TH1 and TH2 cells, as well as related antibody isotype responses. These findings provide suitable explanation for the observations in the experimental model of asthma showing that allergic inflammatory responses and bronchial hyperresponsiveness may be susceptible to HR1 blockade. Apparently, the various effects of histamine on immune regulation are due to differential expression and regulation of 4 histamine receptors and their distinct intracellular signals. In addition, differences in affinities of these receptors is highly decisive on the biological effects of histamine and drugs that target histamine receptors. This article highlights novel discoveries in histamine immunobiology and discusses their relevance to the allergic inflammatory responses.

Histamine↗
PubMed2001

Histamine regulates T-cell and antibody responses by differential expression of H1 and H2 receptors.

Many pathological processes, including those causing allergies and autoimmune diseases, are associated with the presence of specialized subsets of T helper cells (TH1 and TH2) at the site of inflammation. The diversity of TH1 and TH2 function is not predetermined but depends on signals that drive the cells towards either subset. Histamine, released from effector cells (mast cells and basophils) during inflammatory reactions can influence immune response. Here we report that histamine enhances TH1-type responses by triggering the histamine receptor type 1 (H1R), whereas both TH1- and TH2-type responses are negatively regulated by H2R through the activation of different biochemical intracellular signals. In mice, deletion of H1R results in suppression of interferon (IFN)-gamma and dominant secretion of TH2 cytokines (interleukin (IL)-4 and IL-13). Mutant mice lacking H2R showed upregulation of both TH1 and TH2 cytokines. Relevant to T-cell cytokine profiles, mice lacking H1R displayed increased specific antibody response with increased immunoglobulin-epsilon (IgE) and IgG1, IgG2b and IgG3 compared with mice lacking H2R. These findings account for an important regulatory mechanism in the control of inflammatory functions through effector-cell-derived histamine.

Animals↗
PubMed2000

Histamine receptor expression on peripheral blood lymphocytes is influenced by specific and nonspecific activation.

Histamine is a physiological mediator which exerts both effector and regulatory functions through its receptors on various cells. The aim of the study was to investigate changes in histamine receptor expression on peripheral blood lymphocytes affected by stimulation with both specific and nonspecific stimuli. Lymphocytes were obtained from both healthy and allergic subjects. Cells were incubated with various allergens (mixed grass pollen, Lolium perenne, Dermatophagoides pteronyssinus 1, bee venom, phospholipase A2) and nonspecific (fMLP, PMA/ionomycin, LPS) stimuli. The percentage of histamine-binding cells was determined with a fluorescence microscope after incubation with histamine-fluorescein. In control subjects histamine binding after stimulation with allergens was not significantly changed. In contrast, in allergic subjects stimulation with specific allergens resulted in significantly increased histamine binding. Nonspecific stimulation caused increased histamine binding to lymphocytes in both allergic subjects and healthy controls. We conclude that specific and nonspecific activation of lymphocytes is associated with increased expression of histamine receptors.

Adolescent↗
PubMed1999

Heparin modulates migration of human peripheral blood mononuclear cells and neutrophils.

Evidence has now accumulated that heparin can significantly affect immune response including allergic inflammation. Cell motility is supposed to be very crucial in this process. Thus the aim of our study was to investigate whether heparin is a chemoattractant for some inflammatory cells and is also capable of influencing chemotaxis induced by typical chemoattractants. Peripheral blood mononuclear cells (PBMCs) and neutrophils from 10 healthy subjects were obtained by gradient centrifugation. Chemotaxis assays towards either heparin (molecular weight 16 kDa) or low molecular weight heparin--fraxiparine (molecular weight 5 kDa) were performed in Boyden chambers. We found that both heparin molecules are chemoattractants for both PBMCs and neutrophils in the wide concentration range (0.1-2000 microg/ml). However, maximal chemotaxis was observed at concentrations 50-100 microg/ml (fraxiparine) and 1-50 microg/ml (heparin). We also found that fraxiparine was able to significantly increase chemokinesis and decrease chemotaxis in the gradient of both fMLP and IL-8. These results indicate that heparin is a potent regulator of cell migration.

Adult↗
PubMed1996

Spontaneous motility and chemotaxis of neutrophils is influenced by glycocorticosteroid therapy.

The migration of neutrophils is an important part of the allergic inflammatory response. The aim of our study was to investigate the effect of glucocorticosteroids (GCS) on the stimulated and unstimulated migration of neutrophils. The study comprised 103 asthmatics including 44 subjects under GCS therapy (20 GCS resistant and 24 GCS sensitive) as well as 96 healthy control individuals. Unstimulated (random) motility as well as chemotactic response towards fMLP (10-8 mol/l) were determined after Boyden method. Neutrophil motility was determined by the distance of the leading front in filter. In both resistant and sensitive asthmatics under GCS therapy we observed significantly increased unstimulated motility as compared to normal controls (p < 0.001). However, this effect was not demonstrated in the GCS untreated group. Neutrophil chemotaxis towards fMLP was increased in GCS untreated group as compared to healthy controls (p < 0.05). In GCS sensitive subjects the chemotatic activity was decreased. In GCS resistant asthmatics it was moderately increased. We conclude that increased unstimulated neutrophil motility might be one of the immunosuppressive mechanisms of GCS by preventing the cell accumulation at the sites of inflammation.

Adult↗
PubMed1996

Influence of bee venom immunotherapy on degranulation and leukotriene generation in human blood basophils.

BACKGROUND: Rapid clinical tolerance can be induced over several hours by very fast bee venom immunotherapy (VIT) protocols. OBJECTIVE: To investigate the mechanisms underlying VIT we examined the changes of blood basophil responsiveness during VIT. METHODS: Seven bee venom allergic patients with a history of severe systemic reactions after a bee sting were investigated. A cumulative dose of 111.1 micrograms bee venom (BV) was administered sc over 3.5 h under intensive care conditions according to an ultra-rush protocol. The release of histamine and the formation of leukotrienes in response to BV, major BV allergen Phospholipase A2 (PLA), IgE receptor cross-linking with the use of monoclonal antibodies against IgE and IgE receptor, as well as IgE independent activation in response to C5a were determined in vitro before and after ultra-rush VIT. RESULTS: We demonstrated a decrease of total histamine in peripheral blood leucocytes just after VIT. Histamine release in response to all the stimuli used is not affected by ultra-rush VIT, if expressed as per cent release of total histamine. However, the absolute amount product released in response to stimulation was decreased, particularly with allergen (BV, PLA). We also found a significant reduction of LTC4 formation after VIT in samples stimulated with specific allergen (BV, PLA). CONCLUSION: Blood basophils are a target for VIT, which induces impaired release of both preformed and newly generated mediators. However, we believe the basic mechanisms of rapid clinical tolerance induced by ultra-rush VIT remain to be investigated.

Antibodies, Monoclonal↗
PubMed1995

Bee venom immunotherapy results in decrease of IL-4 and IL-5 and increase of IFN-gamma secretion in specific allergen-stimulated T cell cultures.

The mechanisms of bee venom immunotherapy (VIT) are largely unknown. The aim of this study was to follow the changes of T cell cytokine secretion during the course of VIT. Ten bee venom-allergic patients with a history of severe systemic reactions, positive skin tests, and bee venom (BV)-specific serum IgE Abs were treated as follows: on the first day, a cumulative dose of 111 micrograms, starting with 0.1 microgram, was administered s.c. under intensive care conditions. Further injections of 100 micrograms BV were given on day 7, day 21, and thereafter at intervals of 4 wk. Blood samples were obtained just before the initiation of VIT, after the last injection on the same day, and before the subsequent BV injections on days 7, 21, and 50 of VIT. Peripheral blood mononuclear cells (PBMC) were stimulated with phospholipase A (PLA), the major BV allergen, or with a control Ag tetanus toxoid (TT). Cytokine secretion was measured 24 h after restimulation of the cultures with solid-phase bound OKT3 F(ab')2 mAbs after 7 days of culture. In PLA-stimulated cultures, VIT resulted in decreased IL-4 and IL-5 and increased IFN-gamma secretion. In TT-stimulated cultures, we observed similar levels of cytokines before and during VIT. We conclude that ultra-rush VIT changes allergen-specific T cell reactivity.

Allergens↗
PubMed1995

Ultra rush bee venom immunotherapy does not reduce cutaneous weal responses to bee venom and codeine phosphate.

BACKGROUND: The rapid administration of bee venom in cumulative doses exceeding the quantity contained in one bee sting is well tolerated by most of the patients during 3.5 h of ultra-rush bee venom immunotherapy (VIT). The mechanism of this tolerance is unknown. OBJECTIVE: The aim of the study was to verify the hypothesis that either slow mediator depletion of mast cells or blockade of their surface receptor mechanisms by increasing doses of allergen might be the major mechanisms of tolerance induced by ultra-rush VIT. METHODS: Nine bee venom allergic patients with a history of severe systemic reactions after a bee sting, positive skin tests and bee venom specific serum IgE antibodies were treated as follows: on the first day a cumulative dose of 111 micrograms was administered over 3.5 h under intensive care conditions. Further injections were given on day 7, day 21 and thereafter at 4 week intervals. Intradermal tests with codeine phosphate (non-specific mast cell degranulation) and bee venom were performed before the initiation of VIT and 30 min after the last injection on the same day as well as before the subsequent bee venom injections. RESULTS: No significant changes of skin reactivity to both codeine phosphate and bee venom were observed on day 1 (before initiation of VIT and after the last injection on the same day). CONCLUSIONS: Ultra-rush VIT does not induce mediator depletion or surface receptor blockade in skin mast cells.

Bee Venoms↗
PubMed1995

Selective restimulation of antigen or allergen preactivated T cells using OKT3 F(ab)2 results in the secretion of TH-1 or TH-2-like cytokine patterns.

BACKGROUND: The synthesis of IgE is regulated by cytokines secreted from T-helper cells. The studies on cytokine secretion by peripheral blood mononuclear cells (PBMC) upon stimulation with antigen or allergen are difficult due to low levels of cytokines, especially of interleukin-4 (IL-4). OBJECTIVE: In this study we tried to establish a culture system, which could enable the measurement of the cytokine profiles in specifically activated cultures. METHODS: Three methods to potentiate cytokine secretion were evaluated: PBMC from bee venom or house dust mite (Dermatophagoides pteronyssinus) allergic patients as well as normal subjects were stimulated either with the major bee venom allergen phospholipase A2 (PLA) or with the major D. pteronyssinus allergen (Der p 1) or with the control antigens tetanus toxoid (TT) and purified protein derivate (PPD). After 7 days of culture the cells were restimulated either with plastic bound OKT3 F(ab)2 monoclonal antibodies (MoAbs), with the appropriate antigen + antigen presenting cells or with IL-2. The secretion of cytokines (IL-4, IFN gamma) was measured after restimulation of the cultures (day 8). RESULTS: While OKT3 F(ab)2 was unable to activate resting T cells, it could restimulate preactivated cells. Restimulation with OKT3 F(ab)2 induced higher IL-4 and IFN gamma secretion than restimulation with IL-2 or antigen. TT and PLA stimulated a similar cytokine secretion profile in normal and PLA allergic subjects with substantial levels of both IL-4 and IFN gamma. In contrast, PPD induced virtually only IFN gamma secretion. Der p 1 stimulated mainly IL-4 secretion but also IFN gamma production in some mite allergic patients. CONCLUSION: We have established a cell culture system, which combines antigen specificity with a strong cytokine inducing signal provided by anti-CD3 MoAbs. TH-1 and TH-2 characteristic cytokine patterns can be observed in short-term PBMC cultures already after 8 days of culture.

Allergens↗
PubMed1993

Specific allergen stimulates increased motility of peripheral blood lymphocytes and neutrophils from atopics; the effect of specific immunotherapy.

The chemotactic response of peripheral blood lymphocytes and neutrophils from pollinotics and healthy subjects in pollen allergen gradients, before and after specific immunotherapy was investigated using modified Boyden method. It was found that lymphocytes and neutrophils from allergic patients only responded in a chemotactic way in the gradient of the specific allergen. This effect could be demonstrated also in the period when the patients were asymptomatic. Preincubation of the cells with antibodies against human IgE results in abrogation of this effect only in lymphocytes. Specific immunotherapy results in the increased motility of lymphocytes and neutrophils in the gradient of specific allergen just after immunotherapy and significantly decreased motility of these cells during the next exposure to allergen (pollen season) as compared to the values observed in these subjects before immunotherapy. Thus the reactivity of these cells is the dynamic process largely dependent upon exposure to allergen.

Adult↗
PubMed1993

[Effect of bacteria on chemotaxis of peripheral blood lymphocytes from nonatopic asthmatics].

The chemotactic response of peripheral blood lymphocytes from nonatopic asthmatics and healthy subjects in the gradients of various bacterial strains obtained from the airways of the asthmatic patients was investigated. The dominant autologous strains were found to be effective chemoattractants for lymphocytes form the asthmatics. However, none of the bacterial strains investigated in this study induced increased motility of lymphocytes from healthy subjects. These findings might explain the mechanisms of the accumulation of lymphocytes in the airways of nonatopic asthmatics.

Adult↗
PubMed1993

[A comparative study on skin tests and allergen-specific IgE levels determined by enzyme allergo-sorbent testing (EAST)].

Ninety seven randomly selected subjects with bronchial asthma and allergic rhinitis were classified for the comparative studies. The level of allergen specific IgE determined by Enzyme Allergo-Sorbent Testing (EAST) was compared with skin tests. The statistically significant correlation was found for 9 selected allergens. However, the Spearman's rank correlation coefficient values varied largely, depending on a given allergen. They ranged from 0.74 (Dermatophagoides pteronyssinus) to 0.33 (Birch pollen) what might be, in the authors' opinion, a result of Bencard allergens use for skin tests and Kallestad allergens for EAST.

Adolescent↗
PubMed1992

Autologous bacteria induce chemotaxis of peripheral blood mononuclear cells (MNC) from non-atopic asthmatics.

The chemotactic response of peripheral blood MNC from healthy subjects and non-atopic asthmatics against the respective pathogen isolated and cultured from sputum of individual patients was investigated. We found that the wide range of concentrations of autologous bacteria induced chemotaxis of MNC from asthmatics but showed no influence on MNC from healthy subjects. This finding might explain the mechanism of lymphocyte accumulation in the lungs of non-atopic asthmatics.

Adolescent↗
PubMed1992

Specific allergen induced motility of peripheral blood mononuclear cells and polymorphonuclear leukocytes in insect sting allergy.

The motility of peripheral blood mononuclear cells (MNC) and polymorphonuclear (PMN) leukocytes from normal and bee venom allergic subjects was investigated by a modified Boyden micropore filter method. The study comprised MNC locomotion in bee venom and histamine gradients and PMN locomotion in bee venom and fMLP gradients. We demonstrated statistically significant increase in MNC and PMN motility towards bee venom in allergic patients group. This effect disappeared after the preincubation of MNC with anti-human IgE antibodies. We observed no such effect in PMN leukocytes. Increased MNC motility in histamine gradient was observed only in control subjects group. Similarly significant increase in PMN locomotion towards fMLP was found in both allergic and control subjects. The results here demonstrated suggest that a specific allergen might be a chemoattractant for peripheral blood MNC and PMN leukocytes from atopics and could be capable to induce non-infectious inflammatory reactions as a result of its interaction with these sensitive cells.

Adolescent↗