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Background Omalizumab, a recombinant anti-IgE antibody, effectively treats chronic spontaneous urticaria. Evidence is lacking in patients with chronic inducible urticarias (CIndUs), which are frequently H 1 -antihistamine resistant. Objective From the current published literature, we aimed to determine the strength of evidence for omalizumab efficacy and safety in the treatment of CIndUs. Methods We performed a PubMed search to identify evidence on omalizumab use in the following 9 CIndU subtypes: symptomatic dermographism, cold urticaria, delayed-pressure urticaria, solar urticaria, heat urticaria, vibratory angioedema, cholinergic urticaria, contact urticaria, and aquagenic urticaria. Results Forty-three trials, case studies, case reports, and analyses were identified. Our review indicates that omalizumab has substantial benefits in patients with various CIndUs. The evidence is strongest for symptomatic dermographism, cold urticaria, and solar urticaria. Little/no evidence was available on vibratory angioedema and aquagenic and contact urticaria. Our review supports rapid onset of action demonstrated through early symptom control in most cases, sometimes within 24 hours. Many patients gained complete/partial symptom relief and substantially improved quality of life. Adverse events were generally low, with omalizumab being well tolerated by most patients, including children. Conclusions A strong body of evidence supports the use of omalizumab in the treatment of patients with therapy-refractory CIndU. More data from randomized controlled studies are warranted. [ABSTRACT FROM AUTHOR]

Background: Patients with chronic idiopathic urticaria/chronic spontaneous urticaria (CIU/CSU) often continue to experience symptoms despite receiving standard-of-care therapy with H1-antihistamines along with 1 or more add-on therapies. Objectives: We sought to evaluate the safety and efficacy of 24 weeks of treatment with omalizumab in patients with persistent CIU/CSU despite treatment with H1-antihistamines at up to 4 times the approved dose plus H2-antihistamines, leukotriene receptor antagonists, or both. Methods: In this phase III study patients were randomized to receive 6 subcutaneous injections at 4-week intervals of either 300 mg of omalizumab or placebo, followed by a 16-week observation period. The primary objective of the study was to evaluate the overall safety of omalizumab compared with placebo. Efficacy (itch severity, hive, and urticaria activity scores) was evaluated at weeks 12 and 24. Results: The overall incidence and severity of adverse events and serious adverse events were similar between omalizumab and placebo recipients; the safety profile was consistent with omalizumab in patients with allergic asthma. At week 12, the mean change from baseline in weekly itch severity score was −8.6 (95% CI, −9.3 to −7.8) in the omalizumab group compared with −4.0 (95% CI, −5.3 to −2.7) in the placebo group (P < .001). Significant improvements were seen for additional efficacy end points at week 12; these benefits were sustained to week 24. Conclusion: Omalizumab was well tolerated and reduced the signs and symptoms of CIU/CSU in patients who remained symptomatic despite the use of H1-antihistamines (up to 4 times the approved dose) plus H2-antihistamines, leukotriene receptor antagonists, or both. [Copyright &y& Elsevier]

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. [Copyright &y& Elsevier]

Background: Primary cellular immunodeficiencies are a group of genetic disorders in which 1 or more components of the cellular immune system are lacking or dysfunctional. Objective: We sought to identify novel mouse mutants that display primary cellular immunodeficiencies. Methods: Genome-wide N-ethyl-N-nitrosourea mutagenesis was performed in mice, followed by a phenotype screen of immunologic blood parameters. Results: We identified novel mouse mutants with isolated B-cell deficiency, combined block in early B- and T-cell development, combined T-cell and natural killer cell reduction, and 3 different forms of T-cell deficiencies. One of the mutants, designated ΔT3, displayed a combined phenotype of increased IgE, absence of peripheral T cells, and block in late thymocyte differentiation. In addition, ΔT3 mice were unable to mount specific humoral immune responses. Chromosomal mapping and sequencing of candidate genes revealed a novel point mutation in the kinase domain of the T-cell receptor ζ chain–associated protein kinase (Zap70). In contrast to Zap70-deficient mice, ΔT3 mutants displayed normal Zap70 mRNA and residual Zap70 protein levels. Complementation studies with Zap70-deficient mice confirmed that the point mutation found in Zap70 was causative for the ΔT3 phenotype, including increased IgE plasma levels, a phenotype that has not been associated with altered Zap70 function in the past. Conclusion: Random genome-wide mutagenesis combined with a phenotype screen can be used to generate novel mouse mutants with primary cellular immunodeficiencies. [Copyright &y& Elsevier]

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 TH2 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 E1–phytoprostanes dose-dependently inhibited LPS-induced IL-12p70 of DCs. In addition, Bet-APEs induced a TH2 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-γ secretion from antigen-specific T cells in the draining lymph nodes. In contrast, intranasal E1- and F1–phytoprostanes downregulated both TH1 and TH2 cytokine production in vivo. Conclusion: Pollen release water-soluble factors that display TH2-polarizing capacities in vivo independently of E1- and F1–phytoprostanes. Clinical implications: Identification of the underlying mechanisms might open new approaches for pharmacologic intervention. [Copyright &y& Elsevier]

Background: Epidemiologic studies show that exposure to particulate air pollution is associated with asthma exacerbation. Ultrafine particles (diameter <100 nm) may contribute to these adverse effects. Objective: To investigate potential adjuvant activity of inhaled elemental carbon ultrafine particles (EC-UFPs) on allergic airway inflammation. Methods: The effects of ultrafine particle inhalation on allergic airway inflammation was analyzed in ovalbumin-sensitized mice and nonsensitized controls. Particle exposure (526 μg/m3, 24 hours) was performed 24, 96, or 168 hours before or 24 or 72 hours after ovalbumin aerosol challenge. Allergic inflammation was analyzed at different time points after allergen challenge by means of bronchoalveolar lavage cell count and cytokine/total protein assays, lung histology, and airway hyperresponsiveness. Results: In sensitized mice, inhalation of ultrafine particles 24 hours before allergen challenge caused a significant increase of bronchoalveolar lavage inflammatory cell infiltrate, protein, IL-4, IL-5, and IL-13 compared with relevant controls. These adjuvant effects were dose- and time-dependent and were still present when particle exposure was performed 4 days before allergen challenge. The adjuvant effect of ultrafine particles was also documented by increased mucus production, peribronchiolar and perivascular inflammation, and enhanced airway hyperresponsiveness. In contrast, particle exposure in sensitized mice after allergen challenge caused only moderate effects, such as a delay of inflammatory infiltrate and a reduction of cytokines in bronchoalveolar lavage fluid. Conclusion: Exposure to ultrafine carbon particles before allergen challenge exerts strong adjuvant effects on the manifestation of allergic airway inflammation. Allergen-sensitized individuals may therefore be more susceptible to detrimental health effects of ultrafine particles. [Copyright &y& Elsevier]

Background: Interactions with microbial pathogens are crucial for the maturation of the immune system. The nucleotide-binding oligomerization domain protein 1 (NOD1) is a cytosolic receptor sensing a muropeptide found mostly in gram-negative bacterial peptidoglycans. NOD1 is located on chromosome 7p14-p15, a region that has been linked with atopy. Recently, polymorphisms of the closely related NOD2 have been associated with atopy-related traits. Objectives: Within a large population-based cohort of German adults (n=1417), a case-control population for atopic eczema (n=454), and a large cohort of parent-offspring trios for atopic eczema (189 trios), we evaluated 11 NOD1 polymorphisms for associations with atopic phenotypes. Methods: Subjects were phenotyped by standardized questionnaires and interviews, skin examination, and serum IgE measurements. Genotyping was performed by using matrix-assisted laser desorption ionization–time of flight mass spectrometry. Results: Analyses revealed significant association of one NOD1 haplotype with atopic eczema in the population-based cohort (P =.004) and the case-control population (P =.003). Another NOD1 haplotype was associated with decreased total IgE (P =.008). In addition, significant associations with total serum IgE levels were observed for polymorphisms rs2907748 (P =.006), rs2907749 (P =.012), and rs2075822 (P =.018). These polymorphisms were significantly associated with atopic eczema and asthma in the family-based association analyses (P =.001-.043). Seven polymorphisms showed significant transmission distortion for total IgE levels (P values < .0001-.029). Conclusion: These data indicate that genetic variants within NOD1 are important determinants of atopy susceptibility. [Copyright &y& Elsevier]

Allergic contact dermatitis and atopic eczema are common skin diseases that seriously affect the patient''s quality of life. Disease models are important for understanding the complex disease mechanisms and for developing better therapeutic strategies. In this review, the latest disease models for studying the pathophysiology and treatment modalities, as well as models used for predictive testing of substances with contact sensitizing potential are discussed. [Copyright &y& Elsevier]

Adherens junctions are sites of contact between epithelial cells in which adhesion is mediated by homophilic interactions of classical cadherins that are linked to the cytoskeleton via catenins. E-cadherin constitutes the major adhesion molecule in adherens junctions of keratinocytes (KC) and mediates the binding of Langerhans cells to KC in vitro. To characterize structures responsible for E-cadherin-mediated binding of Langerhans cells, we utilized Langerhans cells-like fetal skin-derived dendritic cells (FSDDC) capable of E-cadherin-mediated adhesion. Confocal microscopy of FSDDC aggregates demonstrated colocalization of E-cadherin and catenins to areas of cell–cell contact. Immunopreciptiation confirmed a physical association of E-cadherin with intracellular catenins (α-, β-, γ-catenin/plakoglobin and p120CAS). Transmission electron microscopy of FSDDC aggregates revealed structures with features of adherens junctions in areas of cell–cell contact, and post-embedding immunoelectron microscopy localized β-catenin to these regions. To characterize junctions that accounted for the adhesion of Langerhans cells-like dendritic cells and KC, disaggregated FSDDC were cocultured with primary murine KC. Transmission electron microscopy analysis of cocultures demonstrated FSDDC-KC contacts that were analogous to those seen in FSDDC aggregates. Confocal microscopy demonstrated focal accumulations of E-cadherin and colocalization of β-catenin in areas of contact between KC and immature (Langerhans cell-like) dendritic cells, but not in areas of contact between KC and mature (lymph node dendritic cell-like) dendritic cells. E-cadherin in Langerhans cells appears to be localized in structures that resemble adherens junctions formed by nonpolarized epithelial cells. Loss of ability to form or maintain these structures after the induction of Langerhans cells activation/maturation likely results in the attenuation of... [ABSTRACT FROM AUTHOR]

Venom-induced anaphylaxis (VIA) is a common, potentially life-threatening hypersensitivity reaction associated with (1) a specific symptom profile, 2) specific cofactors, and 3) specific management. Identifying the differences in phenotypes of anaphylaxis is crucial for future management guidelines and development of a personalized medicine approach. This study aimed to evaluate the phenotype and risk factors of VIA. Using data from the European Anaphylaxis Registry (12,874 cases), we identified 3,612 patients with VIA and analyzed their cases in comparison with sex- and age-matched anaphylaxis cases triggered by other elicitors (non-VIA cases [n = 3,605]). VIA more frequently involved more than 3 organ systems and was associated with cardiovascular symptoms. The absence of skin symptoms during anaphylaxis was correlated with baseline serum tryptase level and was associated with an increased risk of a severe reaction. Intramuscular or intravenous epinephrine was administered significantly less often in VIA, in particular, in patients without a history of anaphylaxis. A baseline serum tryptase level within the upper normal range (8-11.5 ng/mL) was more frequently associated with severe anaphylaxis. Using a large cohort of VIA cases, we have validated that patients with intermediate baseline serum tryptase levels (8-11 ng/mL) and without skin involvement have a higher risk of severe VIA. Patients receiving β-blockers or angiotensin-converting enzyme inhibitors had a higher risk of developing severe cardiovascular symptoms (including cardiac arrest) in VIA and non-VIA cases. Patients experiencing VIA received epinephrine less frequently than did cases with non-VIA. [ABSTRACT FROM AUTHOR]

Background Component resolution recently identified distinct sensitization profiles in honey bee venom (HBV) allergy, some of which were dominated by specific IgE to Api m 3 and/or Api m 10, which have been reported to be underrepresented in therapeutic HBV preparations. Objective We performed a retrospective analysis of component-resolved sensitization profiles in HBV-allergic patients and association with treatment outcome. Methods HBV-allergic patients who had undergone controlled honey bee sting challenge after at least 6 months of HBV immunotherapy (n = 115) were included and classified as responder (n = 79) or treatment failure (n = 36) on the basis of absence or presence of systemic allergic reactions upon sting challenge. IgE reactivity to a panel of HBV allergens was analyzed in sera obtained before immunotherapy and before sting challenge. Results No differences were observed between responders and nonresponders regarding levels of IgE sensitization to Api m 1, Api m 2, Api m 3, and Api m 5. In contrast, Api m 10 specific IgE was moderately but significantly increased in nonresponders. Predominant Api m 10 sensitization (>50% of specific IgE to HBV) was the best discriminator (specificity, 95%; sensitivity, 25%) with an odds ratio of 8.444 (2.127-33.53; P = .0013) for treatment failure. Some but not all therapeutic HBV preparations displayed a lack of Api m 10, whereas Api m 1 and Api m 3 immunoreactivity was comparable to that of crude HBV. In line with this, significant Api m 10 sIgG 4 induction was observed only in those patients who were treated with HBV in which Api m 10 was detectable. Conclusions Component-resolved sensitization profiles in HBV allergy suggest predominant IgE sensitization to Api m 10 as a risk factor for treatment failure in HBV immunotherapy. [ABSTRACT FROM AUTHOR]

Background: Recurrent bacterial and fungal infections, eczema, and increased serum IgE levels characterize patients with the hyper-IgE syndrome (HIES). Known genetic causes for HIES are mutations in signal transducer and activator of transcription 3 (STAT3) and dedicator of cytokinesis 8 (DOCK8), which are involved in signal transduction pathways. However, glycosylation defects have not been described in patients with HIES. One crucial enzyme in the glycosylation pathway is phosphoglucomutase 3 (PGM3), which catalyzes a key step in the synthesis of uridine diphosphate N-acetylglucosamine, which is required for the biosynthesis of N-glycans. Objective: We sought to elucidate the genetic cause in patients with HIES who do not carry mutations in STAT3 or DOCK8. Methods: After establishing a linkage interval by means of SNPchip genotyping and homozygosity mapping in 2 families with HIES from Tunisia, mutational analysis was performed with selector-based, high-throughput sequencing. Protein expression was analyzed by means of Western blotting, and glycosylation was profiled by using mass spectrometry. Results: Mutational analysis of candidate genes in an 11.9-Mb linkage region on chromosome 6 shared by 2 multiplex families identified 2 homozygous mutations in PGM3 that segregated with disease status and followed recessive inheritance. The mutations predict amino acid changes in PGM3 (p.Glu340del and p.Leu83Ser). A third homozygous mutation (p.Asp502Tyr) and the p.Leu83Ser variant were identified in 2 other affected families, respectively. These hypomorphic mutations have an effect on the biosynthetic reactions involving uridine diphosphate N-acetylglucosamine. Glycomic analysis revealed an aberrant glycosylation pattern in leukocytes demonstrated by a reduced level of tri-antennary and tetra-antennary N-glycans. T-cell proliferation and differentiation were impaired in patients. Most patients had developmental delay, and many had psychomotor retardation. Conclusion: Impairment of PGM3 function leads to a novel primary (inborn) error of development and immunity because biallelic hypomorphic mutations are associated with impaired glycosylation and a hyper-IgE–like phenotype. [Copyright &y& Elsevier]

Background: Detection of IgE to recombinant Hymenoptera venom allergens has been suggested to improve the diagnostic precision in Hymenoptera venom allergy. However, the frequency of sensitization to the only available recombinant honeybee venom (HBV) allergen, rApi m 1, in patients with HBV allergy is limited, suggesting that additional HBV allergens might be of relevance. Objective: We performed an analysis of sensitization profiles of patients with HBV allergy to a panel of HBV allergens. Methods: Diagnosis of HBV allergy (n = 144) was based on history, skin test results, and allergen-specific IgE levels to HBV. IgE reactivity to 6 HBV allergens devoid of cross-reactive carbohydrate determinants (CCD) was analyzed by ImmunoCAP. Results: IgE reactivity to rApi m 1, rApi m 2, rApi m 3, nApi m 4, rApi m 5, and rApi m 10 was detected in 72.2%, 47.9%, 50.0%, 22.9%, 58.3%, and 61.8% of the patients with HBV allergy, respectively. Positive results to at least 1 HBV allergen were detected in 94.4%. IgE reactivity to Api m 3, Api m 10, or both was detected in 68.0% and represented the only HBV allergen–specific IgE in 5% of the patients. Limited inhibition of IgE binding by therapeutic HBV and limited induction of Api m 3– and Api m 10–specific IgG4 in patients obtaining immunotherapy supports recent reports on the underrepresentation of these allergens in therapeutic HBV preparations. Conclusion: Analysis of a panel of CCD-free HBV allergens improved diagnostic sensitivity compared with use of rApi m 1 alone, identified additional major allergens, and revealed sensitizations to allergens that have been reported to be absent or underrepresented in therapeutic HBV preparations. [Copyright &y& Elsevier]

Background: Allergic contact dermatitis is one of the most common occupational diseases. A main protective mechanism in those who do not develop allergic contact dermatitis is tolerance induction by repeated exposure to low doses of contact allergen, which is termed low zone tolerance (LZT). The mechanisms that determine the tolerance induction in subjects with LZT are still elusive. Objective: We performed analysis of the role of CD4+CD25+ forkhead box protein 3 (FOXP3)–positive regulatory T (Treg) cells and dendritic cells (DCs) in mice with LZT. Methods: Mechanisms of tolerance induction were analyzed in a murine model of LZT by using FOXP3 and IL-10 reporter mice, as well as mice that allow the selective depletion of Treg cells or DCs. Results: Depletion of CD4+CD25+FOXP3+ Treg cells during tolerance induction completely abolishes the development of LZT, resulting in a pronounced contact hypersensitivity response. Adoptive transfer experiments, depletion studies, and use of cell type–specific deficient mice revealed that IL-10 production is critical for the suppressor function of Treg cells in mice with LZT and that tolerogenic CD8+CD11c+ DCs located in the skin-draining lymph nodes are essential for LZT. In the absence of Treg cells, DCs did not develop tolerogenic functions, indicating that activated IL-10+ Treg cells might imprint the tolerogenic DC phenotype. Cell communication analysis revealed that the education of tolerogenic DCs might involve a direct interaction with Treg cells mediated by gap junctions. Subsequently, induction of tolerogenic CD11c+ DCs leads to the generation of hapten-specific CD8+ Treg cells, which protect against contact hypersensitivity. Conclusions: Our data demonstrate critical interactions between CD4+CD25+FOXP3+ Treg cells and tolerogenic CD8+CD11c+ DCs during the induction of LZT. [Copyright &y& Elsevier]

Background: A subgroup of patients with chronic spontaneous urticaria (CU) exhibits IgE antibodies directed against autoantigens, such as thyroperoxidase (TPO). We conducted this study to investigate whether such patients with CU with IgE against TPO benefit from treatment with omalizumab, a humanized anti-IgE mAb licensed for the treatment of severe persistent allergic (IgE-mediated) asthma. Objectives: We sought to assess the efficacy of omalizumab treatment in patients with CU with IgE autoantibodies against TPO. Methods: In this multicenter, randomized, double-blind, placebo-controlled study patients with CU (male/female, 18-70 years of age) with IgE autoantibodies against TPO who had persistent symptoms (wheals and pruritus) despite standard antihistamine therapy were randomized to receive either omalizumab (75-375 mg, dose determined by using the approved asthma dosing table) or placebo subcutaneously once every 2 or 4 weeks for 24 weeks. The primary end point was the change from baseline in mean weekly urticaria activity score after 24 weeks of treatment, as calculated from patients’ diaries. The safety and tolerability of omalizumab were also assessed. Results: Of the 49 randomized patients (omalizumab, n = 27; placebo, n = 22), 42 completed the study. At week 24, patients demonstrated a mean reduction in the weekly urticaria activity score from baseline of 17.8 with omalizumab and 7.9 with placebo (P = .0089). Complete protection from wheal development was observed in 19 (70.4%) patients in the omalizumab group compared with only 1 (4.5%) patient in the placebo group. The rate of adverse events was similar in both groups. Conclusions: The results of this study indicate that omalizumab is an effective treatment option for patients with CU with IgE autoantibodies against TPO who are refractory to conventional treatment. [ABSTRACT FROM AUTHOR]

Honeybee ( Apis mellifera ) venom (HBV) represents an ideal model to study the role of particular venom components in allergic reactions in sensitized individuals as well as in the eusociality of Hymenoptera species. The aim of this study was to further characterize the HBV components C1q-like protein (C1q) and PDGF/VEGF-like factor 1 (PVF1). C1q and PVF1 were produced as recombinant proteins in insect cells. Their allergenic properties were examined by determining the level of specific IgE antibodies in the sera of HBV-allergic patients (n = 26) as well as by their capacity to activate patients' basophils (n = 11). Moreover, the transcript heterogeneity of PVF1 was analyzed. It could be demonstrated that at least three PVF1 variants are present in the venom gland, which all result from alternative splicing of one transcript. Additionally, recombinant C1q and PVF1 from Spodoptera frugiperda insect cells exhibited specific IgE reactivity with approximately 38.5% of sera of HBV-allergic patients. Interestingly, both proteins were unable to activate basophils of the patients, questioning their role in the context of clinically relevant sensitization. Recombinant C1q and PVF1 can build the basis for a deeper understanding of the molecular mechanisms of Hymenoptera venoms. Moreover, the conflicting results between IgE sensitization and lack of basophil activation, might in the future contribute to the identification of factors that determine the allergenic potential of proteins. [ABSTRACT FROM AUTHOR]

T H 2-biased immunity to parasites and allergens is often associated with increased levels of antigen-specific and high affinity IgE. The role in reacting against minute amounts of target structures and to provoke severe anaphylactic reactions renders IgE a mechanistically outstanding isotype. IgE represents the least abundant serum antibody isotype and exhibits a variety of peculiarities including structure, extensive glycosylation and effector functions. Despite large progress in antibody technologies, however, the recombinant access to isotypes beyond IgG such as IgE still is scarce. The capacity of expression systems has to meet the complex structural conformations and the extensive posttranslational modifications that are indispensable for biological activity. In order to provide alternatives to mammalian expression systems with often low yield and a more complex glycosylation pattern we established the recombinant production of the highly complex IgE isotype in insect cells. Recombinant IgE (rIgE) was efficiently assembled and secreted into the supernatant in yields of >30 mg/L. Purification from serum free medium using different downstream processing methods provided large amounts of rIgE. This exhibited a highly specific interaction with its antigen, therapeutic anti-IgE and its high affinity receptor, the FcεRI. Lectins and glyco-proteomic analyses proved the presence of prototypic insect type N -glycans on the epsilon heavy chain. Mediator release assays demonstrated a biological activity of the rIgE comparable to IgE derived from mammalian cells. In summary the expression in insect cells provides rIgE with variant glycosylation pattern, but retained characteristics and biological activity. Therefore our data contribute to the understanding of functional and structural aspects and potential use of the IgE isotype. [ABSTRACT FROM AUTHOR]

Api m 10 has recently been established as novel major allergen that is recognized by more than 60% of honeybee venom (HBV) allergic patients. Previous studies suggest Api m 10 protein heterogeneity which may have implications for diagnosis and immunotherapy of HBV allergy. In the present study, RT-PCR revealed the expression of at least nine additional Api m 10 transcript isoforms by the venom glands. Two distinct mechanisms are responsible for the generation of these isoforms: while the previously known variant 2 is produced by an alternative splicing event, novel identified isoforms are intragenic chimeric transcripts. To the best of our knowledge, this is the first report of the identification of chimeric transcripts generated by the honeybee. By a retrospective proteomic analysis we found evidence for the presence of several of these isoforms in the venom proteome. Additionally, we analyzed IgE reactivity to different isoforms by protein array technology using sera from HBV allergic patients, which revealed that IgE recognition of Api m 10 is both isoform- and patient-specific. While it was previously demonstrated that the majority of HBV allergic patients display IgE reactivity to variant 2, our study also shows that some patients lacking IgE antibodies for variant 2 display IgE reactivity to two of the novel identified Api m 10 variants, i.e. variants 3 and 4. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which discusses case studies related to the skin disease punctuate palmoplantar keratoderma (PPK).

Abstract: The endocannabinoid system (ECS) consists of two cannabinoid (CB) receptors, namely CB1 and CB2 receptor, and their endogenous (endocannabinoids) and exogenous (cannabinoids, e.g. delta-9-tetrahydrocannabinol (THC)) ligands which bind to these receptors. Based on studies suggesting a role of THC and the ECS in inflammation, the objective of this study was to examine their involvement in type I hypersensitivity using a murine model of allergic airway inflammation. THC treatment of C57BL/6 wildtype mice dramatically reduced airway inflammation as determined by significantly reduced total cell counts in bronchoalveolar lavage (BAL). These effects were greatest when mice were treated during both, the sensitization and the challenge phase. Furthermore, systemic immune responses were significantly suppressed in mice which received THC during sensitization phase. To investigate a role of CB1/2 receptors in this setting, we used pharmacological blockade of CB1 and/or CB2 receptors by the selective antagonists and moreover CB1/CB2 receptor double-knockout mice (CB1 −/−/CB2 −/−) and found neither significant changes in the cell patterns in BAL nor in immunoglobulin levels as compared to wildtype mice. Our results indicate that the activation of the ECS by applying the agonist THC is involved in the development of type I allergies. However, CB1/CB2 receptor-independent signalling seems likely in the observed results. [Copyright &y& Elsevier]