Absence Of Allergen Research Articles

Diagnostic de l’IgE-réactivité par analyse des composants moléculaires (test ISAC)

Specific IgE-reactivities have first been implemented by the use of allergenic extracts then purified or recombinant major allergens. The frequent cross-reactivity (CR) due to vegetal and insect carbohydrate determinants has been suppressed by the use of bacteria originated recombinant allergens. CR linked to homology of amino acid sequences leads to classification of allergens, either species specific or cross-reactive ones. The micro array technology (ISAC) makes a component-resolved diagnosis possible by the analysis of 103 allergens. The assessment of this technique may be applied to different pathologies. Negative tests in eight cases of idiopathic anaphylaxis are reported. The ISAC microassay applied to atopic dermatitis shows different polysensitization profiles in 22 children compared to adults. The extensive association of aeroallergen and food allergen sensitizations is a hallmark of eosinophilic esophagitis. Another indication is to set a patient-taylored immunotherapy to pollens and mites. Present restrictions are the CR without clinical relevance (PR-10 family and tropomyosins), the poor performance of certain allergens (wheat allergens, Ana c 2, Ana o 3), the absence of allergens from the following allergenic sources: mustard, lupine, lentils, almond, walnut, buckwheat. In the near future, ISAC could be applied to epidemiological studies and to the follow-up of immunotherapies studied by specific IgG4s. Present prospects are to conduct thorough investigations about the efficiency of the currently available allergens, and to develop computerized algorithms taking into account clinical profiles and patterns of sensitization to improve the diagnosis of clinically relevant sensitization and to achieve the prediction of persistence and severity.

Size Effects of Polystyrene Nanoparticles on Atopic Dermatitis-like Skin Lesions in NC/NGA Mice

Nano-sized particles are diffusing in the environment with the development of nanotechnology. Polystyrene (PS) nanoparticles are modified industrial products and pharmaceutical agents, however, adverse effects of PS nanoparticles remain to be elucidated. In the present study, we investigated the effects of PS nanoparticles with different sizes on the atopic dermatitis (AD)-like skin lesions in NC/Nga mice assumed to show the skin barrier defect/dysfunction in the presence or absence of mite allergen. Male NC/Nga mice were injected intradermally with three different-sized PS nanoparticles (25, 50, or 100 nm) and/or mite allergen into their right ears. We evaluated clinical scores, ear thickening, histological findings and the local protein expression of inflammatory molecules in the ear and Ig production in serum. PS nanoparticles aggravated AD-like skin lesions related to mite allergen, which was paralleled by the local protein levels of interleukin-4, CCL2/monocyte chemotactic protein-1, CCL3/macrophage inflammatory protein-1 alpha, and CCL4/macrophage inflammatory protein-1 beta. In contrast, PS nanoparticles decreased interferon-gamma expression. Furthermore, exposure to PS nanoparticles induced ear swelling and CC-chemokine expression in the absence of allergen. These effects were greater with the smaller PS nanoparticles than with the larger ones regarding overall trend. These results suggest that exposure to PS nanoparticles under skin barrier defect/dysfunction can exacerbate AD-like skin lesions related to mite allergen in a size-dependent manner. The enhancing effects may be accounted for by T helper 2-biased immune responses. Furthermore, PS nanoparticles can evoke skin inflammation via the overexpression of CC-chemokines even in the absence of allergen in atopic subjects.

Single-Walled and Multi-Walled Carbon Nanotubes Promote Allergic Immune Responses in Mice

The adjuvant effect of particles on allergic immune responses has been shown to increase with decreasing particle size and increasing particle surface area. Like ultrafine particles, carbon nanotubes (CNTs) have nano-sized dimensions and a large relative surface area and might thus increase allergic responses. Therefore, we examined whether single-walled (sw) and multi-walled (mw) CNTs have the capacity to promote allergic responses in mice, first in an sc injection model and thereafter in an intranasal model. Balb/cA mice were exposed to three doses of swCNT, mwCNT, as well as ultrafine carbon black particles (ufCBPs, Printex90) during sensitization with the allergen ovalbumin (OVA). Five days after an OVA booster, OVA-specific IgE, IgG1, and IgG2a antibodies in serum and the numbers of inflammatory cells and cytokine levels in bronchoalveolar lavage fluid (BALF) were determined. Furthermore, ex vivo OVA-induced cytokine release from mediastinal lymph node (MLN) cells was measured. In separate experiments, differential cell counts were determined in BALF 24 h after a single intranasal exposure to the particles in the absence of allergen. We demonstrate that both swCNT and mwCNT together with OVA strongly increased serum levels of OVA-specific IgE, the number of eosinophils in BALF, and the secretion of Th2-associated cytokines in the MLN. On the other hand, only mwCNT and ufCBP with OVA increased IgG2a levels, neutrophil cell numbers, and tumor necrosis factor-alpha and monocyte chemoattractant protein-1 levels in BALF, as well as the acute influx of neutrophils after exposure to the particles alone. This study demonstrates that CNTs promote allergic responses in mice.

Titanium Dioxide Nanoparticles Aggravate Atopic Dermatitis-Like Skin Lesions in NC/Nga Mice

Titanium dioxide (TiO(2)) nanoparticles are produced abundantly and used ubiquitously in various cosmetic products. However, it remains to be determined whether transdermal exposure to TiO(2) nanoparticles affects atopic dermatitis (AD), which has been increasing in developed countries. We investigated the effects of different sized TiO(2) nanoparticles on AD-like skin lesions induced to mite allergen in NC/Nga mice assumed to show skin barrier dysfunction/defect. Male mice were injected intradermally with TiO(2) nanoparticles of three sizes (15, 50, or 100 nm) and/or mite allergen into their right ears. We evaluated clinical scores, ear thickening, histological findings and the protein expression of T helper (Th) 1 and Th2 cytokines in the ear, and the levels of Ig and histamine in serum. TiO(2) nanoparticles aggravated AD-like skin lesions related to mite allergen in NC/ Nga mice. The enhancing effects are paralleled by the overproduction of IL-4 in the skin, the levels of total IgE and histamine in serum regarding the overall trend. In contrast, TiO(2) nanoparticles decreased the local expression of IFN-gamma in the presence of allergen. Additionally, TiO(2) nanoparticles alone significantly increased histamine levels in serum and IL-13 expression in the ear. However, different effects related to the size differences of TiO(2) nanoparticles were not observed. In conclusion, exposure to TiO(2) nanoparticles under skin barrier dysfunction/defect can exacerbate AD symptoms through Th2-biased immune responses. Furthermore, TiO(2) nanoparticles can play a significant role in the initiation and/or progression of skin diseases following the barrier dysfunction/defect by histamine release even in the absence of allergen.

Antagonists of the Prostaglandin D2 Receptor CRTH2

Prostaglandin D(2) (PGD(2)) is produced by mast cells, Th2 lymphocytes and dendritic cells and causes activation of Th2 lymphocytes, eosinophils and basophils through a high-affinity interaction with the G protein-coupled receptor chemoattractant homologous receptor expressed on Th2 cells (CRTH2, also known as DP(2)). Activation of CRTH2 induces chemotaxis of Th2 lymphocytes and eosinophils and has the unusual property of promoting cytokine production by Th2 lymphocytes in the absence of allergen or co-stimulation. The ability of supernatants from immunologically activated mast cells to activate Th2 cells and eosinophils is mediated by CRTH2. This receptor also plays an important role in amplifying allergic responses through paracrine activation of Th2 cells. Pharmacological blockade or genetic ablation of CRTH2 is associated with a reduction in airways inflammation and reduced levels of mucus, Th2 cytokines and immunoglobulin E. The central role played by CRTH2 in mediating these effects suggests that antagonism of this receptor is an attractive approach to the treatment of chronic allergic disease.

Effects of nano particles on cytokine expression in murine lung in the absence or presence of allergen

Particulate matter (PM) can exacerbate allergic airway diseases. Health effects of PM with a diameter of less than 100 nm, called nano particles, have been focused. We have recently demonstrated that carbon nano particles (14, 56 nm) exaggerate allergic airway inflammation in mice. In the present study, we investigated the effects of repeated pulmonary exposure to carbon nano particles on the expression of a variety of cytokines in the absence or presence of allergen in mice. ICR mice were divided into six experimental groups. Vehicle, two sizes of carbon nano particles, ovalbumin (OVA), and OVA + nano particles were administered intratracheally. Nano particles increased the lung protein levels of thymus and activation-regulated chemokine (TARC), macrophage inflammatory protein (MIP)-1alpha, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the absence or presence of allergen. The enhancement was more prominent with 14 nm of nano particles than with 56 nm of nano particles in overall trend. 14 nm nano particle exposure significantly enhanced the lung expressions of interleukin (IL)-2 and IL-10 in the presence of allergen as compared with allergen exposure. These results suggest that pulmonary exposure to nano particles can induce the lung expression of TARC, MIP-1alpha, GM-CSF in the absence of allergen and can enhance that of TARC, MIP-1alpha, GM-CSF, IL-2, and IL-10 in the presence of allergen. The enhancing effects are more prominent with smaller particles.

IgE-Dependent Activation of T cells by Allergen in Atopic Dermatitis: Pathophysiologic Relevance

The importance of interactions between allergen and IgE in allergen-mediated activation of T lymphocytes from patients with atopic dermatitis (AD) is unclear. A role for this interaction is implied by past evidence for IgE-facilitated presentation of allergen to T cells, but this phenomenon has only been demonstrated in specific in vitro systems biased to maximize the effect. It is therefore not known whether the process is relevant in patients. We now show that the responses to allergen of unmodified peripheral blood mononuclear cells (PBMC) from individual AD patients are significantly greater in the presence of fresh, unheated, IgE-containing autologous serum than the same serum heated under IgE-denaturing conditions or specifically depleted of IgE by immunoprecipitation. In six independent experiments, 59%-67% of the maximal in vitro PBMC response to allergen was found to be dependent upon the presence of IgE in autologous serum used at 5% final concentration. These data provide the first evidence that sufficient amounts of allergen-specific IgE and allergen-reactive T cells occur concomitantly in the blood of individual AD patients to allow IgE-enhanced T cell responses to allergen. We conclude that IgE-enhanced T cell responses are pathophysiologically relevant and a therapeutic target in AD.

Ambient air particles from four European cities increase the primary cellular response to allergen in the draining lymph node

In the RAIAP (respiratory allergy and inflammation due to ambient particles) project, qualitative properties of ambient air particles from Amsterdam, Oslo, Lodz and Rome were investigated in relation to inflammation and allergy. Most collected particle fractions were found to increase the allergen-specific IgE and IgG2a responses after subcutaneous injection of particles with allergen in mice. However, some fractions appeared to skew the antibody response towards more Th1- or Th2-associated antibody isotypes, and the fine fractions were found to be more potent than the coarse fractions with regard to IgE adjuvant activity. In the present study we investigated the cellular response in the draining lymph node 5 days after a subcutaneous injection of selected RAIAP particle fractions. The particles (100 microg) were injected into both hind footpads of BALB/cA mice, in the presence or absence of the allergen ovalbumin (OVA, 50 microg). We also studied if the coarse and fine RAIAP particle fractions affected the cellular responses to OVA differently. The number of lymph node cells, as well as the relative number of B and T lymphocytes and T helper cells were determined. Expression of cell surface molecules (MHC class II, CD86 and CD23) and ex vivo cytokine production (IL-4, IL-10 and IFN-gamma) by the lymph node cells were measured. Overall, particles in the presence of allergen enhanced the levels of the various cellular parameters compared to allergen alone or particles alone. In the absence of allergen, ambient air particles, in contrast to diesel exhaust particles, marginally affected some cellular parameters. By histological examination of the lymph node, the particles appeared to be scattered between the lymphocytes, often localised within macrophage-like (acid phosphatase positive) cells. The cell parameters measured could, for the individual sample, neither predict the degree of a Th2- or Th1-skewed antibody response, nor the stronger antibody adjuvant capacity of the fine than the coarse particle fractions. In conclusion, we have shown that coarse and fine ambient air particles from different European cities enhance the cellular response in the draining lymph node after injection with an allergen. In the absence of allergen, ambient particles only marginally affected the cellular parameters.

In vivo nasal challenge with diesel exhaust particles enhances expression of the CC chemokines rantes, MIP-1alpha, and MCP-3 in humans.

Diesel exhaust particles (DEP) enhance allergic inflammation by increasing in vivo IgE and cytokine production in the human upper respiratory mucosa. CC chemokines have been shown to play an important role in inflammation. We examined whether DEP could alter the production of CC chemokines by cells residing in the human nasal mucosa. At both 6 and 24 h following intranasal DEP challenge, the levels of nasal RANTES, MIP-1alpha, and MCP-3 were significantly elevated compared to baseline. In contrast, DEP did not enhance levels of Eotaxin at any time, demonstrating that the action of DEP was not simply a global effect on all CC chemokines. Challenge with saline resulted in no significant change in expression of any chemokine at any time. Challenge with DEP also resulted in an increase in total cell counts in nasal lavage fluids. Increases in lymphocyte, monocyte/macrophage, and neutrophil cells were observed but there was no change in eosinophil cell numbers. In contrast, there was a significant enhancement of ECP protein levels in washes performed 6 to 24 h after DEP challenge. Elevated specific nasal chemokine expression following exposure to DEP likely participates in the inflammation, cellular infiltration, and increase in IgE observed in the absence of allergen.

New insights into the pathogenesis of severe corticosteroid-dependent asthma

Severe asthma is characterized by persistent T-cell activation, as demonstrated in both peripheral blood and bronchial mucosa. Endobronchial biopsy specimens of patients with severe, corticosteroid-dependent asthma revealed increased expression of CD25+ on mucosal T cells. Increased immunoreactivity for IL-5 further supports the evidence that the inflammatory response is orchestrated by T H2-type T cells. Peripheral blood eosinophils and total serum IgE levels were increased in the absence of allergen and despite optimal treatment. The chemokine IL-8 may also be an aggravating factor in severe asthma; as well as being a potent chemotactic and activating factor for neutrophils, it may also be chemoattractant for eosinophils. We have recently detected increased levels of free IL-8 in the peripheral blood of patients with chronic severe asthma but not in healthy control subjects or in patients with mild asthma, even after allergen challenge. In patients with severe asthma there may be an imbalance between IL-8 production and the blocking capacity of IL-8 autoantibodies. Higher levels of IL-8 complexed to IgA autoantibody and increased numbers of activated T cells were also found in patients with unstable asthma compared with patients who had severe but stable disease. We conclude that IL-8 may provide an additional marker of asthma severity and corticosteroid responsiveness. (J A LLERGY C LIN I MMUNOL 1996;98:S22-6.)

New insights into the pathogenesis of severe corticosteroid-dependent asthma

Severe asthma is characterized by persistent T-cell activation, as demonstrated in both peripheral blood and bronchial mucosa. Endobronchial biopsy specimens of patients with severe, corticosteroid-dependent asthma revealed increased expression of CD25+ on mucosal T cells. Increased immunoreactivity for IL-5 further supports the evidence that the inflammatory response is orchestrated by TH2-type T cells. Peripheral blood eosinophils and total serum IgE levels were increased in the absence of allergen and despite optimal treatment. The chemokine IL-8 may also be an aggravating factor in severe asthma; as well as being a potent chemotactic and activating factor for neutrophils, it may also be chemoattractant for eosinophils. We have recently detected increased levels of free IL-8 in the peripheral blood of patients with chronic severe asthma but not in healthy control subjects or in patients with mild asthma, even after allergen challenge. In patients with severe asthma there may be an imbalance between IL-8 production and the blocking capacity of IL-8 autoantibodies. Higher levels of IL-8 complexed to IgA autoantibody and increased numbers of activated T cells were also found in patients with unstable asthma compared with patients who had severe but stable disease. We conclude that IL-8 may provide an additional marker of asthma severity and corticosteroid responsiveness. (J ALLERGY CLIN IMMUNOL 1996;98:S22-6.)

The effect of inhaled gallopamil, a potent calcium channel blocker, on the late-phase response in subjects with allergic asthma

The effect of gallopamil on the late-phase response to inhaled allergen was evaluated in six young adults with allergic asthma in a crossover manner. During 2 study days, subjects received 20 mg of inhaled gallopamil or placebo 30 minutes before challenge with the same dose of allergen. In addition, a histamine challenge was performed 1 1 2 hours before and 24 hours after allergen challenge. On 2 additional study days, in the absence of allergen, basal airway responsiveness to histamine was measured before and after gallopamil or placebo administration. During the early phase, the mean ± SD decrease in FEV 1 was 28.0% ± 11.3% after placebo and 25.1% ± 8.4% after gallopamil administration (p > 0.05; β = 0.14). During the late phase, the maximum decrease in FEV 1 was 26.9% ± 11.9% after placebo and 25.3% ± 10.3% after gallopamil administration (p > 0.05; β = 0.21). Airway reactivity to histamine 24 hours after allergen challenge could not be measured in three subjects after gallopamil administration and in one subject after placebo administration because of persistent bronchospasm. In contrast, basal responsiveness to histamine in the absence of allergen was modestly decreased by gallopamil. Since gallopamil is one of the most potent calcium channel blockers when it is administered by the inhaled route, it is unlikely that this group of drugs will be clinically useful for allergic asthma.

The indirect rat mast cell degranulation test reconsidered.

The indirect rat mast cell degranulation test for the detection of human reaginic antibodies was reinvestigated. When the mast cells were incubated with human reaginic serum at concentrations exceeding approximately 3%, a massive, non-specific histamine release occurred, irrespective of the presence or absence of allergen. At tolerated serum concentrations (below 3%), the allergen concentration did not influence the release process. We conclude that the indirect rat mast cell test is not applicable as an alternative test system for the study of immediate hypersensitivity in humans.

Allergic syndromes in the absence of allergens: Presidential address

Allergic syndromes in the absence of allergens: Presidential address