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Increased Serum Soluble ST2 In Asthmatic Children and Recurrent Early Wheezers
AB238 Abstracts
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Asthma Susceptibility Due To Environmental Programming Of Innate Immunity In Utero Sarah Manners, BS1, Rafeul Alam, MD, PhD, FAAAAI1, David A. Schwartz, MD2, Magdalena M. Gorska, MD, PhD1; 1National Jewish Health, Denver, CO, 2University of Colorado Denver School of Medicine, Aurora, CO. RATIONALE: Most asthma begins in first years of life. This early onset cannot be merely attributed to genetic defects as asthma prevalence is increasing. Instead, epidemiological studies suggest the role of prenatal and early childhood environmental exposures, including exposure to diesel exhaust. Despite compelling epidemiological evidence, limited progress has been made to understand mechanisms. The key obstacle is paucity of animal models. Animal models are essential as intentional prenatal exposures of humans are unethical. The goal of this study was to establish a mouse model of asthma susceptibility through prenatal diesel exhaust exposure. METHODS: Pregnant C57BL/6 females repeatedly received intranasal applications of diesel exhaust particles (DEP) or phosphate-buffered saline (PBS). Offspring underwent suboptimal immunization and challenge with ovalbumin (OVA) or received PBS. Pups were examined for features of asthma and transcription from DEP-sensitive loci. RESULTS: Maternal DEP exposure made offspring hypersensitive to OVA. These pups demonstrated airway inflammation and hyperresponsiveness, elevated serum OVA-specific IgE and increased pulmonary and systemic Th2/Th17-type cytokines. These cytokines were primarily produced by natural killer (NK) cells. Antibody-mediated depletion of NK cells prevented airway inflammation. Asthma susceptibility was associated with augmented levels of the aryl hydrocarbon receptor (AhR) signature transcripts and transcripts characteristic of the oxidative stress response. Features of asthma were either marginal or absent in OVA-treated pups of PBS-exposed females. CONCLUSIONS: We developed a mouse model linking maternal DEP exposure to asthma in progeny. Asthma in offspring is driven by NK cells and is characterized by increased transcription from AhR and oxidative stress–regulated loci.
MONDAY
821
Rhinovirus Challenge Augments Allergen Responsiveness In Basophils Of Atopic Asthmatics Rachana Agrawal, PhD, Thomas A. E. Platts-Mills, MD, PhD, FAAAAI, Peter W. Heymann, MD, Judith A. Woodfolk, MBChB, PhD, FAAAAI; University of Virginia, Charlottesville, VA. RATIONALE: Rhinovirus infections result in asthma exacerbations in atopic asthmatics; however, the mechanisms for this remain unclear. Binding of allergen to IgE receptor on the surface of basophils and dendritic cells (DCs) plays a pivotal role in driving Th2 responses in atopic asthma. We sought to test how in vivo rhinovirus exposure impacts the IgE pathway. METHODS: PBMCs from atopic asthmatics and non-atopic controls were cultured for 24 hours with allergen, and markers downstream of IgE receptor (Syk and TSLP receptor) were then analyzed in DCs and basophils by flow cytometry. A subset of asthmatics were challenged intranasally with human rhinovirus 16 and cell phenotypes analyzed in PBMC cultures established immediately before challenge, and at days 4 and 21 postchallenge. RESULTS: Basophils and DCs from atopic asthmatics (geometric mean total IgE5553 IU/ml [361-848 IU/ml]) showed a propensity to markedly upregulate TSLP receptor on their surface in response to IgE receptor ligation. In rhinovirus infected asthmatics, this effect was augmented in basophils, but not DCs, and was only observed 21 days post-challenge. Fluxes in intracellular Syk levels were observed 4 days post-infection in both basophils and DCs, and levels were restored at day 21. No changes in surface levels of IgE receptor or serum levels of total IgE or allergenspecific IgE antibodies occurred. CONCLUSIONS: Rhinovirus infection influences intracellular Syk levels and promotes the IgE/TSLP receptor axis in basophils. These findings provide new insight into how rhinovirus and IgE might interact
J ALLERGY CLIN IMMUNOL FEBRUARY 2014
during the acute and chronic phase of rhinovirus infection in atopic asthmatics.
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Der p 3 Allergen Activated Ano-1 Channel On Afferent Airway Nerves Regulates Th2 Cell Responses Mr. Mayur Patil, MS1, Dr. Edward G. Brooks, MD2, Dr. Michael Henry, DDS, PhD1, Dr. Armen Akopian, PhD3; 1UTHSCSA, san antonio, TX, 2Univ. Texas Health Science Center San Antonio, San Antonio, TX, 3 UTHSCSA, San Antonio, TX. RATIONALE: Afferent airway nerves could contribute to the initiation, development and maintenance of airway inflammation, a characteristic of many pulmonary diseases. This ‘‘axon reflex’’ theory implies that afferent airway nerves recognize environmental cues, including allergens, and trigger maladaptive transformation of the respiratory immune system. The aims of this study were to identify channel(s) activated by Der p 3 allergen, and examine its role in Der p 3 and HDM-induced asthma. METHODS: We used pharmacological approach coupled with electrophysiology and Ca2+-imaging to identify the channels mediating Der p 3 responses in airway neurons of nodose/jugular ganglia. Channel-specific antagonists were employed to evaluate the channels role in development of Der p 3 and HDM-induced asthma in mouse models. Th2 responses were evaluated by total and differential immune cell counts from BALF, measuring cytokine release in BALF and examining lung pathology. Data were analyzed using one-way or two-way ANOVA. RESULTS: We demonstrate that Ano-1, a Ca2+-dependent Cl-channel, mediates Der p 3, but not HDM responses in airway neurons. Ano-1 also controls allergen-evoked neuropeptide release in bronchi. Administration of Ano-1 antagonists during the sensitization and challenge steps by Der p 3 resulted in a significant reduction in eosinophilia and certain cytokines. Ano-1 did not alter the HDM asthma model phenotypes. CONCLUSIONS: Ano-1 mediates Der p 3 responses in airway nerves and contributes to development Th2 response by Der p 3, but not HDM in mouse asthma models. Our observation provides novel therapeutic opportunities for the treatment of asthma induced by certain allergens.
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Increased Serum Soluble ST2 In Asthmatic Children and Recurrent Early Wheezers Prof. Hai Lee Chung, MD, PhD, Dr. Eun Joo Lee; Catholic University of Taegu, Taegu, South Korea. RATIONALE: Soluble ST2 (sST2) has been reported to regulate Th2 response. In this study, serum levels of sST2, Th1, and Th2 cytokines were measured in recurrent early wheezers and asthmatic children. We aimed to investigate if there is any difference or similarities in immune responses between those two patient groups. METHODS: Fifty-nine patients admitted with exacerbation of wheezing or asthma were enrolled. Two patient groups were defined: children with _6yrs, N521) and recurrent early wheezers (< _2yrs, N538). atopic asthma (> Recurrent early wheezers were divided based on their atopic status: 19 were atopic and 19 were non-atopic. sST2, IL-33, IL-5, and IFN-r were measured in serum samples from two patient groups. sST2 and cytokine levels in both patient groups were compared with their age-matched controls. Their relationships with blood eosinophils, serum IgE levels, and severity of symptom were also evaluated. RESULTS: sST2 and IL-5 were significantly increased both in asthmatic children (P50.02, P50.004) and recurrent early wheezers (P50.01, P50.001) compared to their age-matched controls. IL-5 was significantly higher in atopic wheezers compared with non-atopic wheezers (P50.04). Severity score showed a positive correlation with sST2 and IFN-r in asthmatic children, but only with IFN-r in early wheezers. There was an inverse correlation between sST2 and blood eosinophil counts both in asthmatic children and atopic recurrent wheezers. CONCLUSIONS: Our study suggests that sST2 might regulate allergic inflammation by suppressing eosinophilia and play an important role in pathophysiology of acute exacerbation of wheezing or asthma both in asthmatic children and early wheezers.
820
Asthma Susceptibility Due To Environmental Programming Of Innate Immunity In Utero Sarah Manners, BS1, Rafeul Alam, MD, PhD, FAAAAI1, David A. Schwartz, MD2, Magdalena M. Gorska, MD, PhD1; 1National Jewish Health, Denver, CO, 2University of Colorado Denver School of Medicine, Aurora, CO. RATIONALE: Most asthma begins in first years of life. This early onset cannot be merely attributed to genetic defects as asthma prevalence is increasing. Instead, epidemiological studies suggest the role of prenatal and early childhood environmental exposures, including exposure to diesel exhaust. Despite compelling epidemiological evidence, limited progress has been made to understand mechanisms. The key obstacle is paucity of animal models. Animal models are essential as intentional prenatal exposures of humans are unethical. The goal of this study was to establish a mouse model of asthma susceptibility through prenatal diesel exhaust exposure. METHODS: Pregnant C57BL/6 females repeatedly received intranasal applications of diesel exhaust particles (DEP) or phosphate-buffered saline (PBS). Offspring underwent suboptimal immunization and challenge with ovalbumin (OVA) or received PBS. Pups were examined for features of asthma and transcription from DEP-sensitive loci. RESULTS: Maternal DEP exposure made offspring hypersensitive to OVA. These pups demonstrated airway inflammation and hyperresponsiveness, elevated serum OVA-specific IgE and increased pulmonary and systemic Th2/Th17-type cytokines. These cytokines were primarily produced by natural killer (NK) cells. Antibody-mediated depletion of NK cells prevented airway inflammation. Asthma susceptibility was associated with augmented levels of the aryl hydrocarbon receptor (AhR) signature transcripts and transcripts characteristic of the oxidative stress response. Features of asthma were either marginal or absent in OVA-treated pups of PBS-exposed females. CONCLUSIONS: We developed a mouse model linking maternal DEP exposure to asthma in progeny. Asthma in offspring is driven by NK cells and is characterized by increased transcription from AhR and oxidative stress–regulated loci.
MONDAY
821
Rhinovirus Challenge Augments Allergen Responsiveness In Basophils Of Atopic Asthmatics Rachana Agrawal, PhD, Thomas A. E. Platts-Mills, MD, PhD, FAAAAI, Peter W. Heymann, MD, Judith A. Woodfolk, MBChB, PhD, FAAAAI; University of Virginia, Charlottesville, VA. RATIONALE: Rhinovirus infections result in asthma exacerbations in atopic asthmatics; however, the mechanisms for this remain unclear. Binding of allergen to IgE receptor on the surface of basophils and dendritic cells (DCs) plays a pivotal role in driving Th2 responses in atopic asthma. We sought to test how in vivo rhinovirus exposure impacts the IgE pathway. METHODS: PBMCs from atopic asthmatics and non-atopic controls were cultured for 24 hours with allergen, and markers downstream of IgE receptor (Syk and TSLP receptor) were then analyzed in DCs and basophils by flow cytometry. A subset of asthmatics were challenged intranasally with human rhinovirus 16 and cell phenotypes analyzed in PBMC cultures established immediately before challenge, and at days 4 and 21 postchallenge. RESULTS: Basophils and DCs from atopic asthmatics (geometric mean total IgE5553 IU/ml [361-848 IU/ml]) showed a propensity to markedly upregulate TSLP receptor on their surface in response to IgE receptor ligation. In rhinovirus infected asthmatics, this effect was augmented in basophils, but not DCs, and was only observed 21 days post-challenge. Fluxes in intracellular Syk levels were observed 4 days post-infection in both basophils and DCs, and levels were restored at day 21. No changes in surface levels of IgE receptor or serum levels of total IgE or allergenspecific IgE antibodies occurred. CONCLUSIONS: Rhinovirus infection influences intracellular Syk levels and promotes the IgE/TSLP receptor axis in basophils. These findings provide new insight into how rhinovirus and IgE might interact
J ALLERGY CLIN IMMUNOL FEBRUARY 2014
during the acute and chronic phase of rhinovirus infection in atopic asthmatics.
822
Der p 3 Allergen Activated Ano-1 Channel On Afferent Airway Nerves Regulates Th2 Cell Responses Mr. Mayur Patil, MS1, Dr. Edward G. Brooks, MD2, Dr. Michael Henry, DDS, PhD1, Dr. Armen Akopian, PhD3; 1UTHSCSA, san antonio, TX, 2Univ. Texas Health Science Center San Antonio, San Antonio, TX, 3 UTHSCSA, San Antonio, TX. RATIONALE: Afferent airway nerves could contribute to the initiation, development and maintenance of airway inflammation, a characteristic of many pulmonary diseases. This ‘‘axon reflex’’ theory implies that afferent airway nerves recognize environmental cues, including allergens, and trigger maladaptive transformation of the respiratory immune system. The aims of this study were to identify channel(s) activated by Der p 3 allergen, and examine its role in Der p 3 and HDM-induced asthma. METHODS: We used pharmacological approach coupled with electrophysiology and Ca2+-imaging to identify the channels mediating Der p 3 responses in airway neurons of nodose/jugular ganglia. Channel-specific antagonists were employed to evaluate the channels role in development of Der p 3 and HDM-induced asthma in mouse models. Th2 responses were evaluated by total and differential immune cell counts from BALF, measuring cytokine release in BALF and examining lung pathology. Data were analyzed using one-way or two-way ANOVA. RESULTS: We demonstrate that Ano-1, a Ca2+-dependent Cl-channel, mediates Der p 3, but not HDM responses in airway neurons. Ano-1 also controls allergen-evoked neuropeptide release in bronchi. Administration of Ano-1 antagonists during the sensitization and challenge steps by Der p 3 resulted in a significant reduction in eosinophilia and certain cytokines. Ano-1 did not alter the HDM asthma model phenotypes. CONCLUSIONS: Ano-1 mediates Der p 3 responses in airway nerves and contributes to development Th2 response by Der p 3, but not HDM in mouse asthma models. Our observation provides novel therapeutic opportunities for the treatment of asthma induced by certain allergens.
823
Increased Serum Soluble ST2 In Asthmatic Children and Recurrent Early Wheezers Prof. Hai Lee Chung, MD, PhD, Dr. Eun Joo Lee; Catholic University of Taegu, Taegu, South Korea. RATIONALE: Soluble ST2 (sST2) has been reported to regulate Th2 response. In this study, serum levels of sST2, Th1, and Th2 cytokines were measured in recurrent early wheezers and asthmatic children. We aimed to investigate if there is any difference or similarities in immune responses between those two patient groups. METHODS: Fifty-nine patients admitted with exacerbation of wheezing or asthma were enrolled. Two patient groups were defined: children with _6yrs, N521) and recurrent early wheezers (< _2yrs, N538). atopic asthma (> Recurrent early wheezers were divided based on their atopic status: 19 were atopic and 19 were non-atopic. sST2, IL-33, IL-5, and IFN-r were measured in serum samples from two patient groups. sST2 and cytokine levels in both patient groups were compared with their age-matched controls. Their relationships with blood eosinophils, serum IgE levels, and severity of symptom were also evaluated. RESULTS: sST2 and IL-5 were significantly increased both in asthmatic children (P50.02, P50.004) and recurrent early wheezers (P50.01, P50.001) compared to their age-matched controls. IL-5 was significantly higher in atopic wheezers compared with non-atopic wheezers (P50.04). Severity score showed a positive correlation with sST2 and IFN-r in asthmatic children, but only with IFN-r in early wheezers. There was an inverse correlation between sST2 and blood eosinophil counts both in asthmatic children and atopic recurrent wheezers. CONCLUSIONS: Our study suggests that sST2 might regulate allergic inflammation by suppressing eosinophilia and play an important role in pathophysiology of acute exacerbation of wheezing or asthma both in asthmatic children and early wheezers.