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Polyinosinic:polycytidylic acid (poly IC), a double-stranded RNA, is an effective adjuvant in vivo. IFN-λs (also termed IL-28/29) are potent immunomodulatory and antiviral cytokines. We demonstrate that poly IC injection in vivo induces large amounts of IFN-λ, which depended on hematopoietic cells and the presence of TLR3 (Toll-like receptor 3), IRF3 (IFN regulatory factor 3), IRF7, IFN-I receptor, Fms-related tyrosine kinase 3 ligand (FL), and IRF8 but not on MyD88 (myeloid differentiation factor 88), Rig-like helicases, or lymphocytes. Upon poly IC injection in vivo, the IFN-λ production by splenocytes segregated with cells phenotypically resembling CD8α(+) conventional dendritic cells (DCs [cDCs]). In vitro experiments revealed that CD8α(+) cDCs were the major producers of IFN-λ in response to poly IC, whereas both CD8α(+) cDCs and plasmacytoid DCs produced large amounts of IFN-λ in response to HSV-1 or parapoxvirus. The nature of the stimulus and the cytokine milieu determined whether CD8α(+) cDCs produced IFN-λ or IL-12p70. Human DCs expressing BDCA3 (CD141), which is considered to be the human counterpart of murine CD8α(+) DCs, also produced large amounts of IFN-λ upon poly IC stimulation. Thus, IFN-λ production in response to poly IC is a novel function of mouse CD8α(+) cDCs and their human equivalents.

Infection with the yeast candida is a quite common disease. Its occurrence might be harmless, however, Candida infections often present with an underlying systemic disease. Thus, candidiasis in some cases can be considered as an indicator for e.g. diabetes mellitus or immune deficiency (i.e. HIV or leukaemia). Of note, we have to distinguish the colonisation and the infection with Candida because only the presence of the yeast together with clinical symptoms is an indication for treatment. The latter has to be adapted according to age, localisation and potentially underlying systemic disease. A special form of Candidiasis constitutes the chronic mucocutaneous candidiasis which can occur in line with hereditary immune deficiencies or also isolated. In the present review we discuss the current status of diagnostic and therapy of mucocutaneous candidiasis as well as the (patho-) immunologic background of yeast infections using the example of a special case of chronic mucocutaneous candidiasis., (Georg Thieme Verlag KG Stuttgart, New York.)

A subgroup of patients with atopic eczema develops acute eczematous reactions to type I allergy-inducing agents such as pollen that clinically resemble type IV allergies induced by haptens like metal ions. To clarify the underlying immunologic mechanisms, this study was designed to map the inflammatory in situ topoproteome of eczematous responses to grass/birch pollen and nickel by using atopy patch test (APT) and nickel patch test (NPT) as an appropriate clinical model, respectively. Biopsies from NPT (n = 6) and APT (n = 6) with positive reactions at 72 h were analysed by multiple epitope ligand cartography (MELC), which enabled to investigate coexpression of 49 different epitopes immunohistochemically in a single given tissue section. Colocalisation of IgE and FcepsilonRI was investigated by confocal microscopy. Compared with APT responses, NPT reactions were dominated by cytotoxic TIA-1 + and CD8 + T cells. In contrast, the immune response in APT reactions appeared more pleiotrope - as detected by colocalisation analysis. Multiple combinatorial molecular phenotype (CMP) motifs containing naive, early maturation and memory T cell (CD45RA, CD7, CD44, CD45R0), and general activation markers (CLA, HLA-DR, CD13, CD29, CD58, CD71, CD138) were significantly higher expressed in APT when compared with NPT reactions. APT response was confirmed to be accompanied by IgE bound to FcepsilonRI. In summary, our results demonstrate that the NPT reaction is clearly dominated by cytotoxic events, while the APT reaction to pollen grains is more heterogeneous and elicits a combined humoral and cellular immune reaction.

Chronic mucocutaneous candidiasis (CMC) defines a heterogeneous group of orphan and inherited syndromes characterised by chronic and recurrent infections of the skin and mucosa with the yeast Candida. Increasing evidence suggests that this inefficient defence against Candida species is reflected by a DC/T cell defect which results in an impaired Th17 and Th1 immune response and, consecutively, a failed immune instruction of tissue cells. Little is known about the incidence and prognosis of CMC. Clinically, the main complications are debilitating hands (Candida granuloma) and oesophageal stricture with potential mal-digestion/-absorption. Furthermore, the chronic infections are likely a risk factor for the development of squamous cell carcinoma. Since resistance to anti-mycotic drugs evolves rapidly, efficient and flexible therapeutic management is essential for CMC patients.

Th17 is a newly identified lineage of effector T cells involved in autoimmunity and immune responses to pathogens. We demonstrate in this study the pathogenic role of IL-17-producing CD4(+) T lymphocytes in allergic contact dermatitis (ACD) to skin-applied chemicals. IL-17(+) T cells infiltrate ACD reactions and predominantly distribute at the site of heavy spongiosis. Skin IL-17(+) T cells were functionally and phenotypically heterogeneous: although pure Th17 prevailed in ACD skin, hapten responsiveness was restricted to Th1/IL-17 (IFN-gamma(+)IL-17(+)) and Th0/IL-17 (IFN-gamma(+)IL-17(+)IL-4(+)) fractions, and to lesser extent Th2/IL-17 cells. In the IFN-gamma-dominated ACD environment, IL-17-releasing T cells affect immune function of keratinocytes by promoting CXCL8, IL-6, and HBD-2 production. In addition, compared with Th1, supernatants from Th1/IL-17 T cells were much more efficient in inducing ICAM-1 expression on keratinocytes and keratinocyte-T cell adhesiveness in vitro. As a consequence, exposure to combined IFN-gamma and IL-17 rendered keratinocytes susceptible to ICAM-1-dependent Ag nonspecific T cell killing. Thus, IL-17 efficiently amplifies the allergic reaction by rendering virtually all of the T lymphocytes recruited at the site of skin inflammation capable to directly contribute to tissue damage.

The present review aims at giving a condensed view on the current status of therapy of atopic eczema - a common chronically relapsing inflammatory skin disease. Atopic eczema is a multifactorial disease with a tendency for chronification. Owing to the associated genetic factors, therapeutic amelioration of skin symptoms is often only transient. Therefore, treatment basically focuses on symptomatic relief. Atopic treatment should more than any other disease be guided by an individualized approach taking not only the phenotype and genotype of the disease but also psychosocial and gender aspects into account. Significant gains have been made in our understanding of atopic eczema, especially recent insights into genetic and immunologic mechanisms, but still, there is no single treatment to date that has proven to be the quantum leap for atopic patients. Novel treatments have been developed and trialled, however, more studies on novel therapies such as biologicals addressing efficacy, optimum dose and duration of treatment and the target phenotype are urgently needed. Hopefully, the tremendous progress in basic research in the last years will provide new targets for prevention and treatment in the future.

Background: Evidence is accumulating that the pollen exsudate contains an array of non-allergenic, pro-inflammatory and immunomodulatory substances acting on the innate and adaptive immune system. In this context, pollen-associated E(1)-phytoprostanes (PPE(1)) were shown to licence human monocyte-derived dendritic cells for T-helper type 2 (Th2) polarization of naïve T cells., Objective: This study aims at analysing the impact of pollen-associated lipid mediators on cytokine secretion and maturation of 6-sulfo LacNAc(+) dendritic cells (slanDCs), the most abundant native dendritic cell (DC) in human peripheral blood, and further dissecting the biologically active substance(s) within aqueous pollen extracts., Results: Aqueous birch pollen extracts dose-dependently inhibited the lipopolysaccharide (LPS)-induced IL-12 p70 production, while the levels of IL-6 remained unaffected. PPE(1) inhibited secretion of both IL-12 p70 and IL-6. Aqueous pollen extracts, but not PPE(1) or F(1)-phytoprostanes significantly reduced the LPS-induced surface expression of the maturation markers CD80, CD83, CD40 and CCR-7, an effect that was independent of proteins and that was still present in a 3 kDa cut-off fraction of the pollen extract. These effects were observed irrespective of the atopy status of the donors. Finally, slanDCs exposed to aqueous pollen extracts were impaired in eliciting an IFN-gamma response in naïve CD4(+) T cells., Conclusion: Our data show that slanDCs, a subset of human blood DCs with constitutively high potency to induce Th1 responses, are susceptible to the Th2 polarizing effect of low molecular weight, non-protein factors derived from pollen.

Background: Epidemiologic studies reveal a dramatic increase in allergies in the last decades. Air pollution is considered to be one of the factors responsible for this augmentation. The aim of this study was to analyze the impact of urbanization on birch pollen. The birch pollen proteome was investigated in order to identify differences in protein abundance between pollen from rural and urban areas. The allergenicity of birch pollen from both areas was evaluated by assessing its chemotactic potency as well as its protein and allergen contents., Methods: Difference gel electrophoresis (DIGE) was used to analyze the pollen proteome. The chemotactic activity of aqueous pollen extracts was determined by migration assays of human neutrophils., Results: DIGE revealed 26 differences in protein spot intensity between pollen from urban and rural areas. One of these proteins was identified by de novo sequencing as the 14-3-3 protein, which resembles a stress-induced factor in other plant species. Furthermore, extracts from pollen collected in urban areas had higher chemotactic activity on human neutrophils compared to pollen from rural sites., Conclusions: The present study points to an impact of air pollution on allergen carrier proteome and release of chemotactic substances. The increment in proinflammatory substances such as pollen-associated lipid mediators might contribute to the described urban-rural gradient of allergy prevalence. Furthermore, our study suggests that allergenicity is determined by more than the sole allergen content.

Th subsets are defined according to their production of lineage-indicating cytokines and functions. In this study, we have identified a subset of human Th cells that infiltrates the epidermis in individuals with inflammatory skin disorders and is characterized by the secretion of IL-22 and TNF-alpha, but not IFN-gamma, IL-4, or IL-17. In analogy to the Th17 subset, cells with this cytokine profile have been named the Th22 subset. Th22 clones derived from patients with psoriasis were stable in culture and exhibited a transcriptome profile clearly separate from those of Th1, Th2, and Th17 cells; it included genes encoding proteins involved in tissue remodeling, such as FGFs, and chemokines involved in angiogenesis and fibrosis. Primary human keratinocytes exposed to Th22 supernatants expressed a transcriptome response profile that included genes involved in innate immune pathways and the induction and modulation of adaptive immunity. These proinflammatory Th22 responses were synergistically dependent on IL-22 and TNF-alpha. Furthermore, Th22 supernatants enhanced wound healing in an in vitro injury model, which was exclusively dependent on IL-22. In conclusion, the human Th22 subset may represent a separate T cell subset with a distinct identity with respect to gene expression and function, present within the epidermal layer in inflammatory skin diseases. Future strategies directed against the Th22 subset may be of value in chronic inflammatory skin disorders.

Background: A pathogenic role of serine protease inhibitor lymphoepithelial Kazal type-related inhibitor (LEKTI) in atopic dermatitis (AD) is currently in intense debate. Analyses of an association between genetic polymorphisms of SPINK5 and atopic diseases revealed contradictory results. Herein, we assessed the role of LEKTI in AD at an expressional and functional level., Methods: The expression of LEKTI and its inhibitory capacity was measured by real-time polymerase chain reaction and hydrolytic activity assay, respectively, in keratinocyte cell cultures of three AD patients in comparison to cultures of healthy individuals (5x) and Netherton (NS) patients (3x)., Results: Expression of LEKTI was significantly decreased in AD vs. healthy volunteers. Due to reduced protease inhibition, trypsin-like hydrolytic activity in AD was slightly increased, although not significantly., Conclusions: Even though the number of investigated subjects was small and hydrolytic activity was only slightly increased, the results denote that LEKTI might be diminished in AD. The study also disclosed the necessity of functional analyses in addition to genetic investigations to gain further and more detailed insights into the role of LEKTI in AD.

Pollen allergy is characterized by a T(H)2-biased immune response to pollen-derived allergens. However, pollen-exposed epithelia do not encounter pure allergen but rather a plethora of protein and non-protein substances. We demonstrated that pollen liberate lipids with chemical and functional similarities to leukotriens and prostaglandins--the pollen associated lipid mediators (PALMs). To date, two main groups of PALMs have been characterized: The immunostimulatory PALMs activating innate immune cells such as neutrophils and eosinophils, and the immunomodulatory E(1)-phytoprostanes blocking IL-12 production of dendritic cells, resulting in the preferential induction of T(H)2 responses. This article reviews our work in the field of PALMs and their effects on cells of the innate and adoptive immune system. From recent results a general picture starts to emerge in which PALMs (and possibly other pollen-associated substances) may--independently from protein allergens--propagate an overall T(H)2 favoring micromilieu in pollen exposed tissue of predisposed individuals.

Epithelial cells of both the respiratory tract and the skin form a tight barrier against environmental harm. They represent the site of first contact for airborne allergen carriers. Consequently, in this study, we analyzed the uptake of grass pollen allergens by epithelial cells: Phl p 1 was selected as a glycosylated allergen containing disulfide bridges whereas Phl p 6 lacks post-translational modifications. Allergen uptake by the respiratory epithelial cell line A549 reached a plateau at 2 hours, and both allergens were localized intracellularly in non-acidic vesicles. In addition, in A549 cells allergens were exocytosed, suggesting a transcytosis mechanism in the passage of allergens over the respiratory epithelial barrier. In contrast, allergens were predominately localized in lysosomes in keratinocytes, and allergen uptake did not reach a plateau up to 24 hours. Notably, keratinocytes from atopic patients showed a significantly increased uptake of Phl p 1 as compared with healthy donors. Preincubation of epithelial cells with IL-4 and/or IFN-gamma to simulate inflammatory status led to an increased allergen uptake only in keratinocytes. This higher engulfment of allergens by inflammatory-type keratinocytes suggests a higher susceptibility of inflamed skin for the uptake of allergens and consequently a potentially higher risk for sensitization under natural exposure conditions, such as chronic atopic eczema.

In a humid milieu such as mucosal surfaces, pollen grains do not only release allergens but also proinflammatory and immunomodulatory lipids, termed pollen-associated lipid mediators. Among these, the E(1)-phytoprostanes (PPE(1)) were identified to modulate dendritic cell (DC) function: PPE(1) inhibit the DC's capacity to produce IL-12 and enhance DC mediated T(H)2 polarization of naive T cells. The mechanism(s) by which PPE(1) act on DC remained elusive. We thus analyzed candidate signaling elements and their role in PPE(1)-mediated regulation of DC function. Aqueous birch pollen extracts induced a marked cAMP response in DC that could be blocked partially by EP2 and EP4 antagonists. In contrast, PPE(1) hardly induced cAMP and the inhibitory effect on IL-12 production was mostly independent of EP2 and EP4. Instead, PPE(1) inhibited the LPS-induced production of IL-12 p70 by a mechanism involving the nuclear receptor PPAR-gamma. Finally, PPE(1) efficiently blocked NF-kappaB signaling in DCs by inhibiting IkappaB-alpha degradation, translocation of p65 to the nucleus, and binding to its target DNA elements. We conclude that pollen-derived PPE(1) modulate DC function via PPAR-gamma dependent pathways that lead to inhibition of NFkappaB activation and result in reduced DC IL-12 production and consecutive T(H)2 polarization.

The question "What makes an allergen an allergen?" has puzzled generations of researchers, and we still do not have a conclusive answer. Despite increasing knowledge about the molecular and functional characteristics of allergens that have been identified, we still do not fully understand why some proteins are clinically relevant allergens and most are not. Different approaches have been taken to identify the structural and functional features of allergens, aiming at developing methods to predict allergenicity and thus to identify allergens. However, none of these methods has allowed a reliable discrimination between allergenic and nonallergenic compounds on its own. This review sums up diverse determinants that contribute to the phenomenon of allergenicity and outlines that in addition to the structure and function of the allergen, factors derived from allergen carriers, the environment, and the susceptible individual are of importance.

Background: Patients with atopic eczema (AE) regularly experience colonization with Staphylococcus aureus that is directly correlated with the severity of eczema. Recent studies show that an impaired IL-17 immune response results in diseases associated with chronic skin infections., Objective: We sought to elucidate the effect of IL-17 on antimicrobial immune responses in AE skin., Methods: T cells infiltrating atopy patch test (APT) reactions were characterized for IL-17 secretion to varying stimuli. IL-17-dependent induction of the antimicrobial peptide human beta-defensin 2 (HBD-2) in keratinocytes was investigated., Results: Approximately 10% of APT-infiltrating T cells secreted IL-17 after phorbol 12-myristate 13-acetate (PMA)/ionomycin stimulation. Among these, 33% belonged to the newly characterized subtype T(H)2/IL-17. Despite the capacity to secrete IL-17, specific T-cell clones released only low amounts of IL-17 on cognate allergen stimulation, whereas IL-4, IFN-gamma, or both were efficiently induced. IL-17 secretion was not enhanced by IL-23, IL-1 beta, or IL-6 but was enhanced by the S aureus-derived superantigen staphylococcal enterotoxin B. Both healthy and AE keratinocytes upregulated HBD-2 in response to IL-17, but coexpressed IL-4/IL-13 partially inhibited this effect. In vivo, additional application of staphylococcal enterotoxin B induced IL-17 in APT reactions, whereas IL-4, IFN-gamma, and IL-10 were marginally regulated. Induced IL-17 upregulated HBD-2 in human keratinocytes in vivo., Conclusion: IL-17-capable T cells, in particular T(H)2/IL-17 cells, infiltrate acute AE reactions. Although IL-17 secretion by specific T cells is tightly regulated, it can be triggered by bacteria-derived superantigens. The ineffective IL-17-dependent upregulation of HBD-2 in patients with AE is due to a partial inhibition by the type 2 microenvironment, which could partially explain why patients with AE do not clear S aureus.

Chronic mucocutaneous candidiasis (CMC) constitutes a selective inability to clear infection with the yeast Candida, resulting in persistent debilitating inflammation of skin, nails, and mucous membranes. The underlying defect is unknown. Only recently, IL-17-producing T cells have been reported to be involved in clearing Candida infections. In order to characterize T cellular immune response to Candida, we analyzed T-cell cytokine secretion to Candida antigen and mitogenic stimuli in CMC patients, immunocompetent patients suffering from acute Candida infection, and healthy volunteers. Peripheral blood mononuclear cells (PBMCs) from CMC patients produced significantly lower amounts of IL-17 and IL-22 mRNA and protein when stimulated with Candida albicans or mitogen in vitro compared with that in matched healthy individuals. Additionally, PBMCs from immunocompetent Candida-infected patients secreted more IL-17 and IL-22 than those of both CMC patients and healthy, non-infected controls. Flow cytometry revealed a decreased number of CCR6+ IL-17-producing T cells in CMC patients, whereas the amount of CCR6+/CCR4+ cells was not altered. Levels of differentiating cytokines for human Th17 cells, IL-1beta and IL-6, tended to be higher in CMC patients. The inability to clear C. albicans in CMC patients could be due to a defect in the immune response of IL-17-producing T cells.

The cyclic guanosine monophosphate (cGMP)/cGMP-dependent protein kinase type I (cGKI) pathway regulates many cellular functions. The current study shows that 8-Br-cGMP stimulates the number of attached primary but not that of subcultured murine vascular smooth muscle cells (VSMCs). These effects of 8-Br-cGMP require the presence of cGKI. In agreement with previous studies, cGKI inhibited the number of cells in repeatedly passaged murine VSMCs. Activation of the cGMP/cGKI pathway in freshly isolated primary VSMCs slightly decreased apoptosis and strongly increased cell adhesion. The stimulation of cell adhesion by cGKI involves an inhibition of the RhoA/Rho kinase pathway and increased exposure of beta(1) and beta(3) integrins on the cell surface. Together, these results identify a novel proadhesive function of cGMP/cGKI signaling in primary VSMCs and suggest that the opposing effects of this pathway on VSMC number depend on the phenotypic context of the cells.

Background: The release of the aeroallergen Bet v 1 from pollen is a major determinant in the etiology of allergic airway disease due to birch pollen., Objective: We determined the release of the major birch pollen allergen Bet v 1 from pollen of birch trees growing in 2 different geographic regions in Germany for 2 consecutive years., Methods: Catkins were collected during pollination in 2002 and 2003 from 82 healthy trees in South (Munich) and West Germany (North Rhine-Westphalia). The release of Bet v 1 from pollen samples was determined by a Bet v 1-specific ELISA., Results: Pollen from South Germany released about 3 times more Bet v 1 than those from West Germany in both 2002 and 2003 (p = 0.034 and p = 0.007, respectively). This was independent of the number of pollen during the pollen flight season. In 2003, the release of Bet v 1 from pollen was more than 5 times higher than in 2002 in both regions (South Germany 6.1 times, p < 0.001; West Germany 5.4 times, p = 0.003)., Conclusions: Despite large individual differences, there seem to be regional and year-to-year variations in Bet v 1 release from birch pollen. Therefore, the combination of pollen count and release of Bet v 1 from this pollen must be assessed to estimate Bet v 1 exposure reliably., (2007 S. Karger AG, Basel)

A 69-year-old woman with a history of acute generalized exanthematic pustulosis (AGEP) caused by metamizole is described. Furthermore, she had suffered from an untreated psoriasis since the age of 20. After an adequate therapy of both psoriasis and AGEP, yellow-brownish, static, coalescing, lucent nodules on the thighs and upper arms became apparent. Histology of skin biopsies revealed a prominent band of mature adipocytes in the dermis. We diagnosed a lipomatous metaplasia of the dermis and hypothesize that this metaplasia occurred as a consequence of the severe and chronic inflammation of the skin., (Copyright 2008 S. Karger AG, Basel.)

Introduction: Eczematous reactions to type I allergy-inducing antigens are documented in a subgroup of patients with atopic eczema. Yet, the underlying immunological mechanisms are not well understood., Material and Methods: To delineate the effect of native pollen grains on human skin of healthy and atopic individuals we performed patch tests (atopy patch test with native pollen grains, PPT). Nickel patch tests (NPT) served as an established model of contact dermatitis. Skin site biopsies were taken 6-96 h after allergen application and investigated immunohistochemically., Results: Histology of positive patch tests showed an influx of mononuclear cells (predominantly CD4+, CD25+, CD45RO+). This influx was detected earlier in the PPT reaction than in the immune response to nickel. A biphasic cytokine response could be detected in the PPT: IL-5 dominated in the early, IFN-gamma in the late phase. The NPT was continuously dominated by IFN-gamma. Dendritic cell subpopulations imitated the earlier kinetics of the mononuclear infiltrate., Discussion: Thus, pollen grains induce eczematous reactions in susceptible individuals. This reaction appears clinically and immunohistochemically similar to the contact hypersensitivity reaction to nickel but follows a faster kinetic and a biphasic course: Th2 and IgE in the early (24 h) and Th1 predominance in the late (96 h) phase., (2007 S. Karger AG, Basel)

Patients suffering from chronic mucocutaneous infections with the yeast Candida albicans (CMC) are discussed to have an underlying primary cellular immunodeficiency. In order to characterise cellular immunity in CMC patients, we analysed chemotaxis and myeloperoxidase (MPO) releases of neutrophils and T cell proliferation and cytokine production to Candida albicans. Patients with chronic mucocutaneous candidiasis (n = 4) and healthy volunteers of same sex and similar age (n = 14) were enrolled into the study. Neutrophil chemotaxis was assessed by transwell migration assay, and MPO release by ELISA. T cell proliferation capacity was investigated by thymidine incorporation and cytokine secretion in supernatants by ELISA. Neither neutrophil migration nor MPO release differed between CMC patients and healthy controls. The relative lymphocyte stimulation index (SI Candida/SI PHA) was heterogenous, but overall it was higher in CMC patients compared to controls. However, Candida-specific IFN-gamma production was significantly reduced in CMC patients. Notably, Candida-specific T cell IL-10 production was markedly higher in CMC patients. The inability to clear the yeast Candida albicans in our CMC patients does not seem to be due to an impaired neutrophil function or reduced antigen specific proliferation of lymphocytes. In fact, our patients tended to proliferate stronger to Candida antigen relative to PHA than healthy controls. However, the impaired Th1 cytokine production with an enhanced IL-10 production could play an important role in the pathogenesis of chronic mucocutaneous Candida infections.

Background: We recently demonstrated that pollen not only function as allergen carriers but also as rich sources of bioactive lipids, such as phytoprostanes, that modulate human dendritic cell (DC) function in a way that results in an enhanced T(H)2 polarization in vitro., Objective: Here we analyzed the immunomodulatory capacities of Betula alba (white birch) aqueous pollen extracts (Bet-APEs) and pollen-associated phytoprostanes in the murine system in vitro and in vivo., Methods: DC function was analyzed in vitro by using BALB/c bone marrow-derived DCs. T-cell responses were analyzed with DO11.10 peptide 323-339 from chicken ovalbumin (OVA)-specific CD4 T cells as responder cells. For in vivo studies, OVA-specific CD4 T cells were adoptively transferred into BALB/c mice. Twenty-four hours later, mice were challenged by means of intranasal application of OVA in the absence or presence of Bet-APEs or phytoprostanes. Polarization of T-cell responses in vivo was analyzed in draining lymph node cells., Results: In vitro Bet-APEs and E(1)-phytoprostanes dose-dependently inhibited LPS-induced IL-12p70 of DCs. In addition, Bet-APEs induced a T(H)2 polarization in vitro. Similarly, intranasal instillation of Bet-APEs in vivo, together with the antigen, lead to increased IL-4, IL-5, and IL-13 secretion and decreased IFN-gamma secretion from antigen-specific T cells in the draining lymph nodes. In contrast, intranasal E1- and F1-phytoprostanes downregulated both T(H)1 and T(H)2 cytokine production in vivo., Conclusion: Pollen release water-soluble factors that display T(H)2-polarizing capacities in vivo independently of E(1)- and F(1)-phytoprostanes., Clinical Implications: Identification of the underlying mechanisms might open new approaches for pharmacologic intervention.

The immune response of atopic individuals against allergens is characterized by increased levels of Th2 cytokines and chemokines. However, the way in which the cytokine/chemokine profile is matched to the type of invading allergen, and why these profiles sometimes derail and lead to disease, is not well understood. We recently demonstrated that pollen modulates dendritic cell (DC) function in a way that results in an enhanced capacity to initiate Th2 responses in vitro. Here, we examined the effects of aqueous birch pollen extracts (Bet.-APE) on chemokine receptor expression and chemokine production by human monocyte-derived DCs. Bet.-APE strongly induced expression and function of CXCR4 and reduced CCR1 and CCR5 expression on immature DCs. In addition, DC treatment with Bet.-APE significantly reduced LPS-induced production of CXCL10/IP-10, CCL5/RANTES; induced CCL22/macrophage-derived chemokine; and did not significantly change release of CCL17/thymus and activation-regulated chemokine. At a functional level, Bet.-APE increased the capacity of LPS-stimulated DCs to attract Th2 cells, whereas the capacity to recruit Th1 cells was reduced. Bet.-APE significantly and dose-dependently enhanced intracellular cAMP, suggesting that water-soluble factors from pollen grains bind a G(alphas)-protein-coupled receptor. E(1)-Phytoprostanes were identified to be one player in the Th2-polarizing potential of aqueous pollen extracts. In summary, our results demonstrate that pollen itself releases regulatory mediators which generate a Th2-promoting micromilieu with preferential recruitment of Th2 cells to the site of pollen exposure.

The interior of motor vehicles is made of a wide variety of synthetic materials, which emit volatile organic compounds (VOC). We tested the health effects of emissions from vehicles exposed to "parked in sunshine" conditions. A new and a 3 year old vehicle with identical interior were exposed to 14 000 W of light. Indoor air was analyzed by GC-MS. Toxicity of extracts of indoor air was assayed in human primary keratinocytes, human lung epithelial A549 cell line, and Chinese hamster V79 lung fibroblasts. In addition, toxicity after metabolic activation by CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, and CYP2E1 was assayed. The effect on type I allergic reaction (IgE-mediated immune response), type IV allergic reaction (T-cell mediated immune response), and irritative potential was evaluated also. A total of 10.9 and 1.2 mg/m(3) VOC were found in new and used motor vehicle indoor air, respectively. The major compounds in the new vehicle were o,m,p-xylenes, C3 and C4-alkylbenzenes, dodecane, tridecane, and methylpyrrolidinone. In the used vehicle they were acetone, methylpyrrolidinone, methylcyclohexane, acetaldehyde, o,m,p-xylenes, ethylhexanol, and toluene. No toxicity was observed in any cell line with or without metabolic activation. Neither did we find an effect on type IV sensitization or an irritative potential. A slight but statistically significant aggravating effect on IgE-mediated immune response of only the new vehicle indoor air was determined (p < 0.05). The IgE-response modulating effect of indoor air might be relevant for atopic individuals. Else no direct toxicity, no toxicity after metabolic activation by cytochrome P450, and no irritative or type IV sensitizing potential of motor vehicle indoor air were found, neither from the new nor used vehicle. Our investigations indicated no apparent health hazard of parked motor vehicle indoor air.

Background: In a subgroup of patients with atopic eczema (AE), aeroallergens are relevant eliciting factors. The atopy patch test (APT) was proposed as inflammation model for AE., Objective: It was the aim of this study to investigate the effect of pretreatment with 1% pimecrolimus cream (Elidel) on the APT and skin prick test (SPT)., Methods: In a randomized, controlled, double-blind study, 20 patients with AE and positive SPT and APT screening reaction to house dust mite Dermatophagoides pteronyssinus, cat dander, grass or birch pollen were enrolled (age 20 +/- 11 years, 55% males). For 2 weeks, patients twice daily applied pimecrolimus and vehicle control to marked fields on their backs and forearms. Then, APT was performed (200 index of reactivity/g extracts in petrolatum; Stallergènes, France) on both fields on the back and SPT was performed on the pretreated forearms., Results: Including only patients with different readings (n = 13), stronger APT suppression of at least 1 ETFAD (European Task Force on Atopic Dermatitis) grade in the pimecrolimus area versus intraindividual control was observed in 10 of these patients after 48 and 72 h (p < 0.05; 90% CI 50.5-93.4). Including all 20 subjects, the analysis still showed a borderline significance compared with the vehicle (p = 0.0564). SPT with histamine and aeroallergens showed a median 7.5-10% reduction in actively pretreated areas (p = 0.086). Immunohistochemical analysis in 2 patients revealed an induction of interferon-gamma in primecrolimus-pretreated skin., Conclusion: APT can be used as a model for AE skin inflammation. It was shown for the first time that pimecrolimus pretreatment has a potential to suppress the development of lesions induced by aeroallergen exposure in patients with AE.

Background: The role of regulatory T cells has been widely reported in the suppression of T-cell activation. A dysfunction in CD4(+)CD25(+) T-regulatory cell-specific transcription factor FoxP3 leads to immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome, often associated with atopic dermatitis. Increasing the number and activity of regulatory T cells in affected organs has been suggested as a remedy in various inflammatory diseases, including allergy., Objective: To determine the presence and function of regulatory T cells in atopic dermatitis., Methods: Immunohistochemistry of lesional atopic dermatitis skin and control skin conditions was used to demonstrate regulatory cells and cytokines in situ. The role of effector and regulatory T cells as well as their specific cytokines in apoptosis in human keratinocyte cultures and artificial skin equivalents was investigated., Results: Human T-regulatory type 1 cells, their suppressive cytokines, IL-10 and TGF-beta, as well as receptors for these cytokines were significantly expressed, whereas CD4(+)CD25(+)FoxP3(+) T-regulatory cells were not found in lesional and atopy patch test atopic dermatitis or psoriasis skin. Both subsets of regulatory T cells suppress the allergen-specific activation of T(H)1 and T(H)2 cells. In coculture and artificial skin equivalent experiments, subsets of T-regulatory cells neither induced keratinocyte death nor suppressed apoptosis induced by skin T cells, T(H)1 cells, IFN-gamma, or TNF-alpha., Conclusion: A dysregulation of disease-causing effector T cells is observed in atopic dermatitis lesions, in association with an impaired CD4(+)CD25(+)FoxP3(+) T-cell infiltration, despite the expression of type 1 regulatory cells in the dermis.

Pollen grains induce allergies in susceptible individuals by release of allergens upon contact with mucosal membranes of the upper respiratory tract. We recently demonstrated that pollen not only function as allergen carriers but also as rich sources of bioactive lipids that attract cells involved in allergic inflammation such as neutrophils and eosinophils. Here we demonstrate that soluble factors from birch (Betula alba L.) pollen activate human dendritic cells (DCs) as documented by phenotypical and functional maturation and altered cytokine production. Betula alba L. aqueous pollen extracts (Bet.-APE) selectively inhibited interleukin (IL)-12 p70 production of lipopolysaccharide (LPS)- or CD40L-activated DC, whereas IL-6, IL-10, and TNFalpha remained unchanged. Presence of Bet.-APE during DC activation resulted in DC with increased T helper type 2 (Th2) cell and reduced Th1 cell polarizing capacity. Chemical analysis of Bet.-APE revealed the presence of phytoprostanes (dinor isoprostanes) with prostaglandin E(1)-, F(1)-, A(1)-, or B(1)-ring systems of which only E(1)-phytoprostanes dose dependently inhibited the LPS-induced IL-12 p70 release and augmented the Th2 cell polarizing capacity of DC. These results suggest that pollen-derived E(1)-phytoprostanes not only resemble endogenous prostaglandin E(2) structurally but also functionally in that they act as regulators that modulate human DC function in a fashion that favors Th2 cell polarization.

The transfer of pollen from floral anther to recipient stigma is the critical reproductive event among higher plants--this is the botanical view of pollen. Proteins and glycoproteins from pollen can function as allergens, environmental molecules interacting with the human immune system to elicit an allergic response in susceptible individuals--this is how allergists and immunologists see pollen grains. Between 10 and 25% of the population now have symptoms of hay fever or allergic asthma and the incidence has more than doubled in the past three decades while the reason(s) for this increment are only hypothetical, but there is a multitude of them. Despite our natural focus on this impact of pollen on human health, pollen have to be considered in a larger context. First of all, to evaluate the bioavailability of allergens from pollen, we have to understand their function and their influence factors. Furthermore, pollen grains are not only releasing proteins eliciting specific immune responses, but they also liberate bioactive lipid mediators and this much more rapidly. And last but not least, recent observations indicate, that pollen do not only induce allergy and thus have a much broader impact on human health. This review is an attempt to favour this holistic view of pollen and their impact on human health., (Copyright 2003 S. Karger AG, Basel)

Since seven years, the 23-year-old woman suffered from severe dysphagia and cutaneous Candida-granulomas on the right side of the head, the nose and both hands. The therapy with different oral antimycotics was ineffective. Intravenously and orally administered high-dose fluconazole has induced healing of the mucocutaneous lesions. The esophageal stenosis, most likely caused by esophageal candidosis, was found as the origin of dysphagia. It was successfully treated by fluconazole and endoscopic dilatations.

Background: Under natural exposure conditions, pollen grains function as allergen carriers that release allergens from internal binding sites on contact with the aqueous phase of mucosa membranes. In addition, we recently demonstrated that pollen are a rich source of eicosanoid-like mediators, which are rapidly released on contact with the aqueous phase., Objective: The current study was designed to characterize the biochemical nature of pollen-derived lipid mediators in more detail and to delineate their biologic activity on polymorphonuclear granulocytes (PMNs)., Methods: Aqueous and lipid extracts from Phleum pratense L and Betula alba L pollen were analyzed by means of HPLC. PMNs were exposed to aqueous extracts or lipid fractions from pollen or to HPLC-purified lipid mediators identified in pollen extracts. Effects on PMNs were tested with transwell migration, calcium mobilization, and surface expression of CD11b., Results: Aqueous pollen extracts (APEs) contained predominantly monohydroxylated products derived of linoleic acid and linolenic acid. In chemotaxis assays PMNs displayed significant migration to APEs. Lipid extracts from pollen and the HPLC fraction containing 13-hydroxy-octadecadienoic acid/hydroxy-linoleic acid and 13-hydroxy-octadecatrienoic acid/hydroxy-linolenic acid induced migratory responses, although to a lesser degree than the APEs. In addition, APE, as well as lipid, extracts induced PMN activation, as documented by means of calcium mobilization and upregulation of CD11b., Conclusion: Pollen grains release mediators that recruit and activate PMNs in vitro. Similar mechanisms may be effective in vivo, suggesting that pollen-derived lipid mediators may act as adjuvants in the elicitation phase of allergic reactions.