Infant milk formulas differ regarding their allergenic activity and induction of T-cell and cytokine responses.

BACKGROUND: Several hydrolyzed cow's milk (CM) formulas are available for avoidance of allergic reactions in CM-allergic children and for prevention of allergy development in high-risk infants. Our aim was to compare CM formulas regarding the presence of immunoreactive CM components, IgE reactivity, allergenic activity, ability to induce T-cell proliferation, and cytokine secretion. METHODS: A blinded analysis of eight CM formulas, one nonhydrolyzed, two partially hydrolyzed (PH), four extensively hydrolyzed (EH), and one amino acid formula, using biochemical techniques and specific antibody probes was conducted. IgE reactivity and allergenic activity of the formulas were tested with sera from CM-allergic patients (n = 26) in RAST-based assays and with rat basophils transfected with the human FcεRI, respectively. The induction of T-cell proliferation and the secretion of cytokines in Peripheral blood mononuclear cell (PBMC) culture from CM allergic patients and nonallergic individuals were assessed. RESULTS: Immune-reactive α-lactalbumin and ß-lactoglobulin were found in the two PH formulas and casein components in one of the EH formulas. One PH formula and the EH formula containing casein components showed remaining IgE reactivity, whereas the other hydrolyzed formulas lacked IgE reactivity. Only two EH formulas and the amino acid formula did not induce T-cell proliferation and proinflammatory cytokine release. The remaining formulas varied regarding the induction of Th2, Th1, and proinflammatory cytokines. CONCLUSION: Our results show that certain CM formulas without allergenic and low proinflammatory properties can be identified and they may also explain different outcomes obtained in clinical studies using CM formulas.

Microarray and allergenic activity assessment of milk allergens.

BACKGROUND: Cow's milk is one of the most common causes of food allergy affecting approximately 2.5% of infants in the first years of their life. However, only limited information regarding the allergenic activity of individual cow's milk allergens is available. OBJECTIVE: To analyse the frequency of IgE reactivity and to determine the allergenic activity of individual cow's milk allergens. METHODS: A nitrocellulose-based microarray, based on purified natural and recombinant cow's milk allergens was used to determine IgE reactivity profiles using sera from 78 cow's milk-sensitized individuals of varying ages. The allergenic activity of the individual allergens was tested using patients' sera for loading rat basophil leukaemia cells (RBL) expressing the α-chain of the human receptor FcεRI. RESULTS: Using the microarray and the RBL assay, cow's milk allergens were assessed for frequency of IgE recognition and allergenic activity. Moreover, the RBL assay allowed distinguishing individuals without or with mild clinical reactions from those with severe systemic or gastrointestinal symptoms as well as persons who grew out cow's milk allergy from those who did not. CONCLUSIONS: Component-resolved testing using milk allergen microarrays and RBL assays seems to provide useful additional diagnostic information and may represent a basis for future forms of prophylactic and therapeutic strategies for cow's milk allergy.

Perinatal maternal application of Lactobacillus rhamnosus GG suppresses allergic airway inflammation in mouse offspring.

BACKGROUND: Clinical studies indicate that maternal exposure to probiotic bacteria may protect from the development of allergic disease later in life. OBJECTIVE: The purpose of this study was to analyse the effects of a perinatal Lactobacillus rhamnosus GG (LGG) supplementation on the development of allergic disorders in offspring. METHODS: Female BALB/c mice received intragastric LGG every other day before conception, during pregnancy and lactation (perinatal supplementation group) or before conception and during pregnancy only (prenatal supplementation group). Cytokine expression of placental tissues was examined. Offspring of LGG-supplemented and sham-exposed mothers were sensitized to Ovalbumin (OVA), followed by aerosol allergen challenges. Development of experimental asthma was assessed by bronchoalveolar lavage analysis, lung histology and lung function measurement. Cytokine production of splenic mononuclear cells was analysed following in vitro stimulation. RESULTS: Intestinal colonization with LGG was observed in mother mice only, but not in the offspring. However, a reduced expression of TNF-alpha, IFN-gamma, IL-5 as well as IL-10 was observed in mice derived from perinatally LGG-supplemented mothers, whereas IL-13 and IL-4 expression remained unchanged. Moreover, in offspring of prenatally or perinatally LGG-supplemented mothers allergic airway and peribronchial inflammation as well as goblet cell hyperplasia were significantly reduced as compared with mice derived from non-supplemented mothers. In contrast, airway hyperresponsiveness to methacholine was not affected. Exposure to LGG during pregnancy only shifted the placental cytokine expression pattern with a markedly increased TNF-alpha level. CONCLUSION: Our data suggest that LGG may exert beneficial effects on the development of experimental allergic asthma, when applied in a very early phase of life. Immunological effects are, at least in parts, mediated via the placenta, probably by induction of pro-inflammatory cell signals.

Deficiency in immunoglobulin G2 antibodies against staphylococcal enterotoxin C1 defines a subgroup of patients with atopic dermatitis.

BACKGROUND AND AIM: Atopic dermatitis (AD) is a common chronic inflammatory skin disease often accompanied by cutaneous Staphylococcus aureus colonization and, in this regard, especially complicated by the presence of superantigen-producing strains. Because IgG antibodies comprise an important defence mechanism of the adaptive immune system against bacteria, it was investigated whether AD patients have an abnormal pattern or distribution of superantigen-specific IgG subclass antibodies in association with disease severity and activity. METHODS: Staphylococcal enterotoxin B (SEB) and staphylococcal enterotoxin C1 (SEC1) specific IgG antibody subclasses were assessed in n=89 adult AD patients with mild to severe disease activity as determined by the SCORAD score and in n=28 healthy age-matched controls. Results were correlated with the current status of bacterial skin colonization and severity score. RESULTS: Thirty-eight per cent of the AD patients showed a selective deficiency in IgG2 antibodies against SEC1 compared with only 14% in the control group. The absence of these antibodies was found in both currently colonized and non-colonized AD patients and was associated with a severe phenotype (SCORAD more than 40 points in two-thirds of the deficient patients). However, these patients had normal production levels of IgG2 antibodies against pneumococcal capsular polysaccharide (PCP) and SEB, but higher IgG1 and IgG4 titres against SEC1. Except for elevated total IgG1, total IgG subclass levels were normal in this AD subgroup. Yet, peripheral blood mononuclear cells (PBMCs) derived from these patients clearly produced IL-4 and IL-5 upon SEC1 re-stimulation whereas PBMCs from those providing SEC1-specific IgG2 antibodies failed in the production of these cytokines. CONCLUSION: A subgroup of AD patients suffers from a selective deficiency to produce anti-SEC1 IgG2 antibodies. This patient group is characterized by a severe AD phenotype.

Prenatal lipopolysaccharide-exposure prevents allergic sensitization and airway inflammation, but not airway responsiveness in a murine model of experimental asthma.

BACKGROUND: Epidemiological evidence underlines the impact of prenatal environmental factors on the development of postnatal allergies. In this regard an inverse correlation between lipopolysaccharide (LPS) exposure and development of childhood allergy has been found. OBJECTIVE: To assess the impact of prenatal LPS exposure on the development of postnatal respiratory allergies in a mouse model of experimental asthma. METHODS: Female BALB/c mice were exposed to LPS before conception and during pregnancy. Several weeks after birth offspring were sensitized to ovalbumin (OVA) followed by aerosol allergen challenges. RESULTS: Prenatal, maternal LPS-exposure enhanced neonatal IFN-gamma, but not IL-4 and IL-2 production. OVA sensitization of prenatally LPS-exposed mice was accompanied by a marked suppression in anti-OVA IgG1 and IgE as well as unchanged IgG2a antibody responses, paralleled by a significant reduction in IL-5 and IL-13 levels following mitogenic stimulation of splenic leucocytes. Assessment of bronchoalveolar lavage fluids following allergen challenges revealed a marked reduction in eosinophils and macrophages in these mice. Surprisingly, development of airway hyper-responsiveness, a hallmark of bronchial asthma, was not affected. CONCLUSION: This study provides first experimental evidence that LPS may already operate in prenatal life in order to modulate the development of allergies in the offspring.

Harmonic lattice behavior of two-dimensional colloidal crystals.

Using positional data from videomicroscopy and applying the equipartition theorem for harmonic Hamiltonians, we determine the wave-vector-dependent normal mode spring constants of a two-dimensional colloidal model crystal and compare the measured band structure to predictions of the harmonic lattice theory. We find good agreement for both the transversal and the longitudinal modes. For q-->0, the measured spring constants are consistent with the elastic moduli of the crystal.

Increased airway responsiveness, allergy-type-I skin responses and systemic anaphylaxis in a humanized-severe combined immuno-deficiency mouse model.

BACKGROUND: In patients with allergic bronchial asthma, a strong relationship between elevated serum IgE antibody titres and the development of increased airway responsiveness (AR) has been demonstrated. To further elucidate the relationship between human (hu) IgE and development of increased AR, we developed an in vivo model utilizing immuno-compromised severe combined immuno-deficiency (SCID) mice. METHODS: SCID mice were either reconstituted with peripheral blood mononuclear cells (PBMC) from non-atopic, healthy or atopic individuals sensitized against house dust mite allergen (Der p), or passively sensitized with plasma from non-atopic, healthy or atopic individuals. RESULTS: In both systems, atopic hu-SCID mice developed increased AR. The following results suggest that these responses were mediated via IgE antibodies: increased AR did not occur after transfer of either PBMC or IgE-negative plasma from non-atopic individuals; increased AR occurred simultaneous with increased serotonin release detected 15 min after allergen-aerosol challenge in bronchoalveolar lavage fluid; and increased AR required at least two allergen-aerosol challenges. SCID mice reconstituted with serum containing anti-Der p IgE antibodies developed positive immediate-type skin test responses to intradermal injection of Der p as well as anti-hu-IgE antibody. In addition, IgE binding to skin mast cells was demonstrated by immunohistochemistry. Furthermore, intravenous challenge of hu anti-Der p positive SCID mice with Der p resulted in systemic anaphylaxis. CONCLUSION: These data provide evidence that passive immunization of SCID mice with hu IgE alters AR and that T cells and eosinophils were not a requirement for the development of increased AR in this model.

Significant correlation of matrix metalloproteinase and macrophage colony-stimulating factor serum concentrations in patients with head and neck cancer.

Serum matrix metalloproteinases (MMPs) and the macrophage colony-stimulating factor (M-CSF) are of potential interest as serum tumor markers in various malignancies. There is still a lack of reliable tumor markers in patients with squamous cell carcinoma of the head and neck (SCCHN). Therefore, the tumor marker potential of MMPs and M-CSF was investigated in these malignancies. Serum of 59 patients suffering from SCCHN and of 59 healthy volunteers was obtained. The concentration of MMP-3, MMP-8, MMP-9, and M-CSF was determined by sandwich enzyme immunoassays. The MMP- 3, -8, -9, as well as the M-CSF serum concentrations were significantly elevated in the patient group, compared to the healthy controls (p<0.001, p<0.05, p<0.001, p=0.002). There was significant correlation between the M-CSF and the MMP-3 serum concentration (p<0.0001), and between the M-CSF and the MMP-8 serum concentration (p=0.005). A significant correlation with the tumor stage was found only for MMP-8. MMP and M-CSF serum concentrations are of potential interest as serum tumor markers in SCCHN.

Murine models of asthma.

In vivo animal models can offer valuable information on several aspects of asthma pathogenesis and treatment. The mouse is increasingly used in these models, mainly because this species allows for the application in vivo of a broad range of immunological tools, including gene deletion technology. Mice, therefore, seem particularly useful to further elucidate factors influencing the response to inhaled allergens. Examples include: the role of immunoregulatory mechanisms that protect against T-helper cell type 2 cell development; the trafficking of T-cells; and the contribution of the innate immunity. However, as for other animal species, murine models also have limitations. Mice do not spontaneously develop asthma and no model mimics the entire asthma phenotype. Instead, mice should be used to model specific traits of the human disease. The present task force report draws attention to specific aspects of lung structure and function that need to be borne in mind when developing such models and interpreting the results. In particular, efforts should be made to develop models that mimic the lung function changes characteristic of asthma as closely as possible. A large section of this report is therefore devoted to an overview of airway function and its measurement in mice.

Macrophage colony-stimulating factor as a tumor marker for squamous cell carcinoma of the head and neck.

It has been demonstrated that in patients with epithelial ovarian cancer and malignant germ cell tumors of the ovary, macrophage colony-stimulating factor (M-CSF) is significantly elevated in the serum compared to healthy individuals. Therefore, M-CSF has been suggested as a tumor marker in these malignancies. In the present study, the tumor marker potential of the serum M-CSF concentration in patients with squamous cell carcinomas of the head and neck (SCCHN) was investigated. The serum M-CSF concentration was determined by a quantitative sandwich enzyme immunoassay in 59 patients suffering from SCCHN and 59 healthy controls. A significant difference in the mean serum concentration of M-CSF between the patients with SCCHN and the control group was found (p = 0.002). The M-CSF serum concentration correlated neither with the stage of disease nor with histopathological grading, and no correlation with serum C-reactive protein was found. The serum M-CSF concentration could be of interest as a tumor marker in SCCHN.

Tumor marker potential of serum matrix metalloproteinases in patients with head and neck cancer.

BACKGROUND: Elevated expression of matrix metalloproteinases (MMPs) is suggested to have tumor marker potential in various tumors. MMPs are capable of disintegrating the basement membrane, which is a main characteristic of tumor invasion. They are specifically inactivated by tissue inhibitors of metalloproteinases (TIMPs). Squamous cell carcinomas of the head and neck (SCCHN) are known to be highly invasive tumors with early locoregional metastatic spread. PATIENTS AND METHODS: To investigate the tumor marker potential of MMPs in SCCHN, MMP-2, -3, -8, -9, -13 and TIMP-1 serum levels were determined in 73 patients and compared to 74 controls. A correlation with T- and N-status, UICC-staging and grading was performed. Additionally, the influence of inflammation on the MMP serum concentration was examined. RESULTS: Significant differences between patients with SCCHN and controls were seen for MMP-3, -8 and -9. A significant correlation was found between MMP-8 concentration and T-status, N-status and UICC-staging. No correlation with the grading of the tumor was observed. Inflammatory diseases did not affect MMP and TIMP levels significantly. CONCLUSION: Some MMPs are elevated in the serum of patients with SCCHN and especially MMP-8 showed interesting tumor marker potential.

[Cytokine profile of a human bone marrow cell culture on exposure to titanium-aluminium-vanadium particles]. / Zytokinprofil einer humanen Knochenmarkszellkultur unter Exposition von Titan-Aluminium-Vanadium-Partikeln.

INTRODUCTION: The purpose of this study was to prove the effect of wear particles, especially Tivanium, in the mechanism of the aseptic loosening of total joint prostheses. MATERIALS AND METHODS: Therefore, human bone marrow cell cultures were incubated with titanium-aluminium-vanadium particles of different concentrations which were added after the seventh day of culture (10(9), 10(8), 10(7), 10(6) particles per ml medium). From this time starts the real culture period (2 weeks). During these two weeks the medium was changed and the supernatants were sampled. Using an ELISA the cytokine levels of interleukin-6, interleukin-1beta, TNF-alpha and LDH were measured approximately every second day (1, 3, 6, 8, 10, 14). As a marker for toxicity the activity of LDH was determined. RESULTS: Incubation of a human bone marrow cell culture with titanium-aluminium-vanadium particles led to a maximum release of interleukin-6, interleukin-1beta, and TNF-alpha at high particle concentration (10(9) particles per ml medium). An increase of interleukin-1beta was only detectable at particle concentrations of 10(9) per ml medium. Exposure of the human bone marrow cell culture to titanium-aluminium-vanadium particles was toxic for high particle concentrations (10(9) particles per ml medium), as reflected by release of the intracellular enzyme LDH. DISCUSSION: This study shows the ability of tivanium wear particles in a human bone marrow cell culture to induce a signfically higher release of proinflammatory and osteolytic mediators which are responsible for the aseptic loosening of prosthesis and the problem of revisions. In comparison to other cell studies, our results were explained by the human bone marrow cell culture. The human bone marrow is the real effector tissue source "in situ" because the prosthesis is localised intramedullarly.

The bidirectional capacity of bacterial antigens to modulate allergy and asthma.

In recent decades, the prevalence of allergic diseases including bronchial asthma, hay fever and atopic dermatitis, has risen steadily in high-income countries. The underlying mechanisms for this phenomenon remain largely unknown. Since the natural mutation rate is low, altered environmental and lifestyle conditions are thought to play an important role. Epidemiological and clinical studies have provided indirect evidence that infections may prevent the development of atopy and atopic disease. This is referred to as the "hygiene hypothesis". According to the hygiene hypothesis, viral and/or bacterial infections could inhibit the T-helper (Th)-2 immune response associated with atopic reactions by stimulating a Th-1 response involved in defence of bacterial infections and delayed-type hypersensitivity reactions. In particular, the prenatal period and early childhood are considered to be critical for the establishment and maintenance of a normal Th-1/Th-2 balance. On the other hand, several studies suggested that infections exacerbate established allergic diseases, e.g. bronchial asthma, airway hyperresponsiveness and atopic dermatitis. Therefore, viral and/or microbial infections and/or their products may have bidirectional effects on the development of allergy and asthma. This review will focus on recent findings related to the interaction between allergic disorders and infectious diseases, with the main emphasis on bacterial infections.

Long-term NO2 exposure induces pulmonary inflammation and progressive development of airflow obstruction in C57BL/6 mice: a mouse model for chronic obstructive pulmonary disease?

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation of the airways, development of emphysema and irreversible airway obstruction. Macrophages, neutrophils and CD8+ T cells and their products have been shown to play an important role in the initiation and maintenance of these processes. In contrast, the mechanisms underlying COPD pathogenesis still remain uncertain. This article focuses on the generation of an animal model that mirrors some features of human COPD in association with a progredient airflow limitation.

Intranasal treatment with a recombinant hypoallergenic derivative of the major birch pollen allergen Bet v 1 prevents allergic sensitization and airway inflammation in mice.

BACKGROUND: The major birch pollen allergen Bet v 1 represents one of the most prevalent environmental allergens responsible for allergic airway inflammation. OBJECTIVE: In the present study we sought to compare the complete recombinant Bet v 1 allergen molecule with genetically produced hypoallergenic fragments of Bet v 1 regarding mucosal tolerance induction in a mouse model of allergic asthma. METHODS: BALB/c mice were intranasally treated with recombinant Bet v 1 or with two recombinant Bet v 1 fragments (F I: aa 1-74; F II: aa 75-160) prior to aerosol sensitization with birch pollen and Bet v 1. RESULTS: Intranasal application of F II, containing the major T cell epitope, led to significant reduction of IgE/IgG1 antibody responses, in vitro cytokine production (IL-5, IFN-gamma, IL-10) and negative immediate cutaneous hypersensitivity reactions comparable to the pretreatment with the complete rBet v 1 allergen. Moreover, airway inflammation (eosinophilia, IL-5) was inhibited by the pretreatment with either the complete Bet v 1 or F II. However, for prevention of airway hyperresponsiveness the complete molecule was required. The mechanisms leading to immunosuppression seemed to differ in their dependence on the conformation of the molecules, since tolerance induced with the complete Bet v 1, but not with F II, was transferable with spleen cells and associated with increased TGF-beta mRNA levels. CONCLUSION: We conclude that mucosal tolerance induction with recombinant allergens and genetically engineered hypoallergenic derivatives thereof could provide a convenient and safe intervention strategy against type I allergy.

Sensitizing capacity and residual allergenicity of hydrolyzed cow's milk formulae: results from a murine model.

BACKGROUND: Cow's milk allergy is the most common cause of clinically relevant adverse reactions to food in infants and children. Partially and extensively hydrolyzed formulae are used for the therapy and prevention of cow's milk allergy. However, the immunogenic potency of hydrolyzed cow's milk formulae to induce and/or enhance the allergic phenotype in vivo is still under debate. The aim of this study was to assess the sensitizing capacity and residual allergenicity of various partially and extensively hydrolyzed cow's milk formulae in a murine model of cow's milk allergy. METHODS: BALB/c mice were immunized with either a cow's milk formula or various partially and extensively hydrolyzed formulae. Immediate cutaneous hypersensitivity reactions and allergen-specific antibody production were assessed. RESULTS: Although immunization with cow's milk resulted in 12/13 cases in a positive skin test response to intradermal injection of cow's milk formulae, only 1 mouse showed a positive skin test to one of the partially hydrolyzed formulae, and none showed positive reactions to other partially hydrolyzed formulae, any of the extensively hydrolyzed formulae, phosphate-buffered saline or the amino acid formula. However, 6 of 8 mice showed positive skin tests when immunized with partially hydrolyzed formulae and with one of the extensively hydrolyzed formulae. CONCLUSIONS: The residual allergenic potential is markedly reduced in many hydrolyzed formulae, but most of the formulae investigated could induce an allergic immune response in BALB/c mice. Our murine model seems to be suitable to investigate the sensitizing capacity of hydrolyzed formulae and to differentiate even between extensively hydrolyzed formulae.

Treatment of allergic airway inflammation and hyperresponsiveness by antisense-induced local blockade of GATA-3 expression.

Recent studies in transgenic mice have revealed that expression of a dominant negative form of the transcription factor GATA-3 in T cells can prevent T helper cell type 2 (Th2)-mediated allergic airway inflammation in mice. However, it remains unclear whether GATA-3 plays a role in the effector phase of allergic airway inflammation and whether antagonizing the expression and/or function of GATA-3 can be used for the therapy of allergic airway inflammation and hyperresponsiveness. Here, we analyzed the effects of locally antagonizing GATA-3 function in a murine model of asthma. We could suppress GATA-3 expression in interleukin (IL)-4-producing T cells in vitro and in vivo by an antisense phosphorothioate oligonucleotide overlapping the translation start site of GATA-3, whereas nonsense control oligonucleotides were virtually inactive. In a murine model of asthma associated with allergic pulmonary inflammation and hyperresponsiveness in ovalbumin (OVA)-sensitized mice, local intranasal administration of fluorescein isothiocyanate-labeled GATA-3 antisense oligonucleotides led to DNA uptake in lung cells associated with a reduction of intracellular GATA-3 expression. Such intrapulmonary blockade of GATA-3 expression caused an abrogation of signs of lung inflammation including infiltration of eosinophils and Th2 cytokine production. Furthermore, treatment with antisense but not nonsense oligonucleotides induced a significant reduction of airway hyperresponsiveness in OVA-sensitized mice to levels comparable to saline-treated control mice, as assessed by both enhanced pause (PenH) responses and pulmonary resistance determined by body plethysmography. These data indicate a critical role for GATA-3 in the effector phase of a murine asthma model and suggest that local delivery of GATA-3 antisense oligonucleotides may be a novel approach for the treatment of airway hyperresponsiveness such as in asthma. This approach has the potential advantage of suppressing the expression of various proinflammatory Th2 cytokines simultaneously rather than suppressing the activity of a single cytokine.

Allergic sensitization and allergen exposure during pregnancy favor the development of atopy in the neonate.

BACKGROUND: Several studies have considered that the in utero environment plays an important role in the onset of the allergic phenotype. We assessed whether allergic sensitization and allergen exposure during pregnancy favor the postnatal onset of allergy in the neonate. METHODS: BALB/c mice were sensitized to ovalbumin (OVA) before mating followed by allergen aerosol exposure during pregnancy. T and B cell responses in offspring were followed up until day 60 postpartum. At the age of 4 weeks offspring were exposed to a heterologous antigen, beta-lactoglobulin (BLG). RESULTS: Pregnant mice developed immediate hypersensitivity responses and Th-2/ Th-0 immunity following allergen aerosol exposure. At birth, T cells from offspring of nonsensitized BALB/c mice were characterized by an impaired IFN-gamma production, which was lowered even further in offspring of OVA-sensitized BALB/c mice. Offspring of OVA-sensitized BALB/c mice responded with immediate-type cutaneous hypersensitivity reactions to OVA which could be related to the pre- and postnatal transfer of maternal OVA-specific IgG1 antibodies. After exposure to BLG, offspring of OVA-sensitized BALB/c mice developed an accelerated Th-2-driven immune response compared to offspring from nonsensitized BALB/c mice as indicated by enhanced anti-BLG IgG1 antibody production and increased numbers of positive immediate-type cutaneous hypersensitivity reactions to BLG. CONCLUSION: Our data suggest that Th-2/Th-0 immunity present during pregnancy has a decisive impact on shaping the Th-1/Th-2 T cell profile in response to postnatal allergen exposure.

Effects of retinoids on in vitro and in vivo IgE production.

BACKGROUND: Retinoids modulate the growth and number of different cell types, including B cells. We could previously show that retinoic acid (RA) strongly inhibits CD40 + IL-4-mediated IgE production in vitro. The aim of the present study was to extend these findings regarding the potential use of retinoids for the treatment of allergic diseases. METHODS: In vitro IgE production was studied in anti-CD40 + IL-4-stimulated peripheral blood mononuclear cells (PBMC) from allergic donors in the presence of 10(-15)-10(-5) M all-trans and 13-cis RA and in ovalbumin (OVA)-sensitized BALB/c mice treated with RA (20 mg/kg) before and during sensitization. IgE and IgG1 levels were determined in the sera of the mice at day 21 after 2 injections (days 1 and 8) of aluminum hydroxide-absorbed OVA. RESULTS: All-trans and 13-cis RA inhibited in vitro IgE production from PBMC in a dose-dependent manner, but were more efficient in atopic dermatitis patients with low total serum IgE levels (< 400 kU/ml), maximal inhibition for all-trans RA at 10(-7) M (87%) and for 13-cis RA at 10(-5) M (96%) compared to patients with high serum IgE levels (>2,000 kU/ml), maximal inhibition for both all-trans and 13-cis RA at 10(-5) M (53 and 39%, respectively). In contrast, the in vivo data from OVA-sensitized mice revealed comparable total IgE and IgG1 levels in control versus all-trans RA or CD336-treated groups, specific IgE was even higher in the CD336-treated group (n = 10, 2,814 ng/ml), and was comparable in mice treated with OVA alone or with additional all-trans RA (n = 10, 1,447 and 1,354 ng/ml, respectively). CONCLUSIONS: These results indicate that the efficacy of retinoids to inhibit IgE production in vitro depends on the frequency of switched cells in the peripheral blood and that in an in vivo model using OVA-sensitized mice, retinoids fail to inhibit IgE production.

Mucosal tolerance induction with hypoallergenic molecules in a murine model of allergic asthma.

Type I allergy, frequently elicited by airborne allergens, has constantly increased within recent years. Birch pollen and its major allergen Bet v 1 represent a major source of type I allergens. By genetic engineering hypoallergenic Bet v 1 fragments were produced, which lost the IgE binding capacity but retained the T cell epitopes. We have established a murine model of aerosol sensitization to birch pollen and its major allergen Bet v 1, leading to type I allergic immune responses and airway hyperresponsiveness. In the present study we demonstrate that mucosal administration of recombinant Bet v 1 prior to sensitization led to allergen-specific suppression of B and T cell responses in vivo and in vitro, reduction of eosinophilic infiltration in the lungs and inhibition of airway hyperresponsiveness. Intranasal pretreatment with the nonanaphylactic fragments of Bet v 1 prevented allergic immune responses and airway inflammation to the same degree as the pretreatment with the complete molecule. We conclude from our studies that mucosal tolerance induction with hypoallergenic molecules could provide a safe and convenient treatment strategy against type I allergies.