Cord blood allergen-specific IgE is associated with reduced IFN-gamma production by cord blood cells: the Protection against Allergy-Study in Rural Environments (PASTURE) Study.

BACKGROUND: It is currently discussed whether allergic sensitization may start in utero under the influence of the maternal immune system and environmental determinants. OBJECTIVE: To investigate the relationship between allergen-specific cord blood (CB) IgE levels, parental sensitization, CB cytokine production, and environmental influences. METHODS: As part of an ongoing multicenter birth cohort study, allergen-specific IgE antibodies against 20 common seasonal, perennial, and food allergens were measured in blood samples from 922 neonates, 922 mothers, and 835 fathers. Supernatants from stimulated CB cells were assessed for the production of IL-5, IFN-gamma, IL-10, and TNF-alpha. RESULTS: Allergen-specific IgE antibodies were detectable in 23.9% of newborns. Contamination with maternal serum was excluded by several means of analyses, including the absence of IgA antibodies. Clear correlation between maternal and fetal IgE was found only for hen's egg, cow's milk, and soybean allergen. Fetal IgE correlated negatively with the level of IFN-gamma production, but not with IL-5 and IL-10. CONCLUSION: Allergen-specific IgE antibodies most probably of fetal origin are detectable in CB and correlate with a lowered CB IFN-gamma production.

Analysis of cytokine levels in human lymphangiomas.

BACKGROUND: Different theories concerning the origin of lymphangiomas have been formulated but their precise pathogenesis is still unknown. This study aimed to analyze the levels of different cytokines in lymphangioma cyst fluids. MATERIALS AND METHODS: Fluid aspirates from lymphangioma cysts of five patients were obtained. The intracystic levels of interleukin (IL)-6, IL-8, IL-2R and tumor necrosis factor alpha (TNFalpha) were determined in four cases before and one case after OK-432 administration using an immunometric assay. RESULTS: Increased IL-6 levels were observed in all cases. Moreover, elevated IL-2R and TNFalpha levels were observed in three out of four and elevated IL-8 levels in two out of four untreated cases. There was a 25-fold increase in IL-6 after repeated OK-432 injections while IL-8, IL-2R and TNFalpha levels did not change significantly. CONCLUSION: These findings suggest that cytokines may be involved in the pathogenesis of lymphangiomas.

Effective prevention and therapy of experimental allergic asthma using a GATA-3-specific DNAzyme.

BACKGROUND: Allergic bronchial asthma is a chronic inflammatory disease of the airways. The transcription factor GATA-3 was shown to play an important role in TH2 cell activation, but also in the regulation of other cell types involved in bronchial asthma including mast cells, eosinophils, and epithelial cells. DNAzymes represent a new class of antisense molecules that combines the specificity of DNA base pairing with an inherent RNA-cleaving enzymatic activity. OBJECTIVE: To develop a GATA-3 mRNA-specific DNAzyme and analyze its allergy-preventing activity in murine models of experimental allergic asthma. METHODS: The most active DNAzyme (termed gd21) was selected by in vitro cleavage assays. Allergic airway inflammation was assessed by inflammatory cell and cytokine analysis within bronchoalveolar lavage. Lung histology, including goblet cell hyperplasia and lung function, was analyzed using head-out body-plethysmography. RESULTS: Intranasal administration of gd21 prevented airway inflammation and mucus production and inhibited development of airway hyperresponsiveness to methacholine in models of acute allergic airway inflammation. Similar effects were also detected in a model of chronic experimental asthma. Interestingly, gd21 was at least as effective as other antisense molecules, and off-target effects were not detected. Further experiments indicated that pulmonary surfactant may facilitate the cellular uptake of gd21 by acting as an endogenous transfectant. CONCLUSION: These results indicate that topical application of the GATA-3-specific DNAzyme is a promising novel approach for the treatment of allergic bronchial asthma.

Immunomodulatory effects of viral TLR ligands on experimental asthma depend on the additive effects of IL-12 and IL-10.

Based on epidemiological data, the hygiene hypothesis associates poor hygienic living conditions during childhood with a lower risk for the development of allergic diseases such as bronchial asthma. The role of viral infections, and especially of viral TLR ligands, within this context remains to be clarified. Viral TLR ligands involve dsRNA and ssRNA which are recognized by TLR-3 or TLR-7, respectively. In this study, we evaluated the impact of TLR-3 or TLR-7 activation on experimental asthma in mice. Systemic application of the synthetic TLR-3 or TLR-7 ligands polycytidylic-polyinosinic acid (p(I:C)) or R-848, respectively, during the sensitization phase prevented the production of OVA-specific IgE and IgG1 Abs and subsequently abolished all features of experimental asthma including airway hyperresponsiveness and allergic airway inflammation. Furthermore, administration of p(I:C) or R-848 to animals with already established primary allergic responses revealed a markedly reduced secondary response following allergen aerosol rechallenges. In contrast to wild-type animals, application of p(I:C) or R-848 to IL-12p35(-/-) mice had no effect on airway inflammation, goblet cell hyperplasia, and airway hyperresponsiveness. However, in the absence of IL-12, the numbers of eosinophils and lymphocytes in bronchoalveolar lavage fluids were still significantly reduced. These partial effects could also be abolished by neutralizing anti-IL-10 Abs in IL-12p35(-/-) mice. These data indicate that TLR-3 or TLR-7 activation by viral TLR ligands has both preventive as well as suppressive effects on experimental asthma which is mediated by the additive effects of IL-12 and IL-10.

Anti-ulcer treatment during pregnancy induces food allergy in mouse mothers and a Th2-bias in their offspring.

The treatment of dyspeptic disorders with anti-acids leads to an increased risk of sensitization against food allergens. As these drugs are taken by 30-50% of pregnant women due to reflux and heartburn, we aimed here to investigate the impact of maternal therapy with anti-acids on the immune response in the offspring in a murine model. Codfish extract as model allergen was fed with or without sucralfate, an anti-acid drug, to pregnant BALB/c mice during pregnancy and lactation. These mothers developed a codfish-specific allergic response shown as high IgG1 and IgE antibody levels and positive skin tests. In the next step we analyzed whether this maternal sensitization impacts a subsequent sensitization in the offspring. Indeed, in stimulated splenocytes of these offspring we found a relative Th2-dominance, because the Th1- and T-regulatory cytokines were significantly suppressed. Our data provide evidence that the anti-acid drug sucralfate supports sensitization against food in pregnant mice and favors a Th2-milieu in their offspring. From these results we propose that anti-acid treatment during pregnancy could be responsible for the increasing number of sensitizations against food allergens in young infants.

Effects of a low-molecular-weight CCR-3 antagonist on chronic experimental asthma.

Eosinophils represent one of the main effector cell populations of allergic airway inflammation and allergic bronchial asthma. Their infiltration correlates with many characteristics of the disease, including airway hyperresponsiveness (AHR) and increased mucus production. CCR-3 is the principle chemokine receptor involved in eosinophil attraction into inflamed tissue. Therefore, antagonizing CCR-3 could be a novel promising approach toward asthma therapy. We investigated the effect of a low-molecular-weight CCR-3 antagonist on established airway inflammation in a chronic model of experimental bronchial asthma. For this purpose, BALB/c mice intraperitoneally sensitized with ovalbumin (OVA) were chronically challenged with OVA aerosol to induce chronic airway inflammation and airway remodeling. The effect of antagonizing CCR-3 on asthma pathology was examined in BAL and lung histology. Airway reactivity was assessed by head-out body plethysmography. Treatment with the CCR-3 antagonist resulted in a marked reduction of eosinophils in the bronchoalveolar lumen and in airway wall tissue, whereas infiltration of lymphocytes or macrophages remained unchanged. The reduction in eosinophil infiltration was accompanied by normalization of AHR and prevention of goblet cell hyperplasia, indicating reduced mucus production. Furthermore, antagonizing CCR-3 prevented airway remodeling as defined by subepithelial fibrosis and increased accumulation of myofibrocytes in the airway wall of chronically challenged mice. These data demonstrate that antagonism of CCR3 reduces eosinophil numbers, which is accompanied by diminution of asthma pathology in a mouse model of established chronic experimental asthma. Therefore, antagonizing CCR-3 represents a new approach toward a promising asthma therapy.

Treatment of allergic asthma by targeting transcription factors using nucleic-acid based technologies.

There is considerable evidence that T-helper 2 (Th2) cells play a central role in the pathogenesis of allergic diseases such as bronchial asthma, hay fever or food allergy. The differentiation of naïve T cells into Th2 cells producing a specific pattern of cytokines is tightly controlled and regulated by transcription factors. Thus down-regulation of mRNA-levels of a single transcription factor leads to a "knock-down" of several mediators simultaneously, representing an advantage compared to earlier approaches involving down-regulation of one intercellular inflammatory mediator, which is unlikely to influence all pathophysiological aspects of the disease. We review the impact of specific and master transcription factors involved in Th2 cell commitment and evaluate approaches for the down-regulation of these proteins by degradation of their mRNA using nucleic-acid based technologies including antisense oligonucleotides, ribozymes, DNAzymes, decoys oligonucleotides and RNA interference.

The immunological basis of the hygiene hypothesis.

The dramatic increase of allergic disorders in the last decades made their study an imperious demand. The increasing incidence of the development of allergic disorders seems to be associated with the modern westernized lifestyle, but causal reasons and the underlying mechanisms are far from being completely understood. Evidences suggest that priming of the immune responses against allergens happens already in utero. In addition, early life events are essential in shaping the immune answer towards the Th1- or Th2-profile, associated with a nonallergic or allergic phenotype, respectively. The hygiene hypothesis suggests that an early life environment rich in normal microbial flora primes the immune system in the Th1 direction towards clinical balance while a 'sterile' environment rather promotes the development of pathological immune phenotypes. In this review we collect epidemiological evidence for this concept. The data suggest an association between environment, lifestyle and the development of allergic diseases. This is the basis for the development of new hypotheses regarding the underlying pathomechanisms. The current view of cellular and molecular mechanisms underlying these phenomena includes fine-balancing between innate immune mechanisms and Th1, Th2 and regulatory T cells. These novel immunoregulatory events may explain the hygiene hypothesis by an interaction of environmental factors with innate immune mechanisms and various subtypes of T-cell responses.

A role for brain-derived neurotrophic factor in B cell development.

In the present study, we demonstrated a significant reduction of B lymphocytes in the blood, spleen and bone marrow of BDNF deficient mice. The observed developmental block in bone marrow B cell development was linked specifically to the Pre-BII stage. B lymphocytes express the BDNF receptors p75NTR and TrkB(gp95), while no BDNF expression was found. However, a strong BDNF expression was demonstrated in bone marrow stromal cells. An increase of intracellular free calcium [Ca2+]i in B lymphocytes after BDNF application confirms a direct responsiveness of B lymphocytes to BDNF. In conclusion, these results suggest a role of BDNF for normal B lymphocyte development through paracrine effects in the bone marrow.