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There is increasing interest in the roles of covalently modified nucleotides in RNA. There has been, however, an inability to account for modifications in secondary structure prediction because of a lack of software and thermodynamic parameters. We report the solution for these issues for N

Background CCR3 is the cognate receptor for major human eosinophil chemoattractants from the eotaxin family of proteins that are elevated in asthma and correlate with disease severity. Objective This proof-of-mechanism study examined the effect of AXP1275, an oral, small-molecule inhibitor of CCR3, on airway responses to inhaled allergen challenge. Methods Twenty-one subjects with mild atopic asthma and documented early and late asthmatic responses to an inhaled aeroallergen completed a randomized double-blind cross-over study to compare early and late allergen-induced asthmatic responses, methacholine PC20 , blood and sputum eosinophils and exhaled nitric oxide after 2 weeks of treatment with once-daily doses of AXP1275 (50 mg) or placebo. Results There was a significant increase in methacholine PC20 after 12 days of AXP1275 treatment compared to placebo (increase of 0.92 doubling doses versus 0.17 doubling doses, P = .01), but this protection was lost post-allergen challenge. There was no effect of AXP1275 on allergen-induced late asthmatic responses, or eosinophils in blood and sputum. The early asthmatic response and exhaled nitric oxide levels were slightly lower with AXP1275, but this did not reach statistical significance. The number of subjects who experienced treatment-emergent adverse events while receiving AXP1275 was comparable placebo. Conclusions & clinical relevance AXP1275 50 mg administered daily was safe and well tolerated, and there was no difference in the type, severity or frequency of treatment-emergent adverse events in subjects while receiving AXP1275 compared to placebo. AXP1275 increased the methacholine PC20 ; however, the low and variable exposure to APX1275 over a short treatment period may have contributed to poor efficacy on other outcomes.

Neutrophils are effector cells recruited to airways in patients with asthma. Migration of neutrophils occurs predominantly through activation of the CXCR1 and CXCR2 receptors by CXC chemokines, including IL-8 and Gro-α. The dual CXCR1/CXCR2 antagonist SCH 527123 has been developed to target neutrophil migration to alleviate airway neutrophilia. This study investigated the effects of SCH 527123 on neutrophil levels within the bone marrow, peripheral blood and airways, and on isolated bone marrow and peripheral blood neutrophil migration from mild allergic asthmatics.Thirteen subjects with mild allergic asthma completed a double blind, placebo-controlled, multi-center crossover study and were randomized to daily dosing of 30 mg SCH 527123 and placebo for 8 days. Subjects provided bone marrow, peripheral blood and sputum samples pre-dosing and on the last day of dosing. Neutrophil numbers were quantified in all samples and chemotaxis assays were performed on neutrophils purified from bone marrow and peripheral blood.Neutrophil numbers fell significantly in the peripheral blood and sputum following treatment with SCH 527123 compared to placebo treatment. No change in neutrophil numbers was observed in bone marrow. SCH 527123 reduced IL-8-induced migration of purified peripheral blood neutrophils (p 0.05), but had limited effects on migration of neutrophils purified from bone marrow.The results from this study demonstrate that oral administration of the dual CXCR1/CXCR2 antagonist SCH 527123 reduces neutrophil levels in the circulation and airways through inhibition of migration. There were no toxic effects of SCH 527123 on granulocytic progenitor cells in the bone marrow.

Background Omalizumab is an established anti-IgE therapy for the treatment of allergic diseases that prevents IgE from binding to its receptor. QGE031 is an investigational anti-IgE antibody that binds IgE with higher affinity than omalizumab. Objective This study compared the effects of QGE031 with those of omalizumab on clinical efficacy, IgE levels, and FceRI expression in a clinical model of allergic asthma. Methods Thirty-seven patients with mild allergic asthma were randomized to subcutaneous omalizumab, placebo, or QGE031 at 24, 72, or 240 mg every 2 weeks for 10 weeks in a double-blind, parallel-group multicenter study. Inhaled allergen challenges and skin tests were conducted before dosing and at weeks 6, 12, and 18, and blood was collected until 24 weeks after the first dose. Results QGE031 elicited a concentration- and time-dependent change in the provocative concentration of allergen causing a 15% decrease in FEV 1 (allergen PC 15 ) that was maximal and approximately 3-fold greater than that of omalizumab ( P = .10) and 16-fold greater than that of placebo ( P = .0001) at week 12 in the 240-mg cohort. Skin responses reached 85% suppression at week 12 in the 240-mg cohort and were maximal at week 18. The top doses of QGE031 consistently suppressed skin test responses among subjects but had a variable effect on allergen PC 15 (2-fold to 500-fold change). QGE031 was well tolerated. Conclusion QGE031 has greater efficacy than omalizumab on inhaled and skin allergen responses in patients with mild allergic asthma. These data support the clinical development of QGE031 as a treatment of asthma.

Dendritic cells (DCs) are antigen-presenting cells essential for the initiation of T-cell responses. Allergen inhalation increases the number of airway DCs and the release of epithelial-derived cytokines, such as IL-33 and thymic stromal lymphopoietin (TSLP), that activate DCs.To examine the effects of inhaled allergen on bone marrow production of DCs and their trafficking into the airways in subjects with allergic asthma, and to examine IL-33 and TSPL receptor expression on DCs.Bone marrow, peripheral blood, bronchoalveolar lavage (BAL), and bronchial biopsies were obtained before and after inhalation of diluent and allergen from subjects with asthma that develop allergen-induced dual responses. Classical DCs (cDCs) were cultured from bone marrow CD34(+) cells. cDC1s, cDC2s, and plasmacytoid DCs were measured in bone marrow aspirates, peripheral blood, and BAL by flow cytometry, and cDCs were quantified in bronchial biopsies by immunofluorescence staining.Inhaled allergen increased the number of cDCs grown from bone marrow progenitors, and cDCs and plasmacytoid DCs in bone marrow aspirates 24 hours after allergen. Allergen also increased the expression of the TSLP receptor, but not the IL-33 receptor, on bone marrow DCs. Finally, inhaled allergen increased the percentage of cDC1s and cDC2s in BAL but only cDC2s in bronchial tissues.Inhaled allergen increases DCs in bone marrow and trafficking of DCs into the airway, which is associated with the development airway inflammation in subjects with allergic asthma. Inhaled allergen challenge also increases expression of TSLP, but not IL-33, receptors on bone marrow DCs.

Rationale: IL-25 is an epithelial-derived cytokine, whose effects are mediated by the IL-25 receptor (IL-17RB), and that has been implicated in the pathogenesis of allergic disease and airway viral responses. Airway myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) are professional antigen-presenting cells. pDCs may play a protective role in asthma and are key players in the innate immune response through recognition of microbial products via Toll-like receptors (TLRs). The effects of inhaled allergens on the expression of IL-17RB by mDCs and pDCs, and the effects of IL-25 on pDCs, are unknown.Objectives: To evaluate allergen-induced changes in IL-17RB expression by mDCs and pDCs and to investigate the effects of IL-25 on pDCs.Methods: Patients with mild atopic asthma (n = 13) were challenged with inhaled allergen. Blood and sputum DCs were enumerated and IL-17RB expression was determined by flow cytometry before and 7 and 24 hours after allergen challenge. The effects of IL-25 on pDC...

INTRODUCTION: Intubated patients with acute respiratory distress syndrome are thought to have a 5-12% incidence of barotrauma, even with protective ventilation However, little is known about the incidence of barotrauma in COVID-19 Due to high rates of observed barotrauma at this center, this retrospective cohort study aims to better characterize the incidence of barotrauma and identify predisposing factors such as inflammatory markers and disease severity indices for this high-mortality complication METHODS: Inclusion criteria were as follows: age over 18 years, positive RT-PCR for SARS-CoV2, admission to the ICU between 03/15/2020 and 06/15/2020, and a score of 5 or higher on the World Health Organization's Ordinal Scale or respiratory rate over 30 breaths per minute on admission Data were collected for the following categories developed by an internal committee of pulmonary/critical care faculty and housestaff based on similar studies: age, sex, body mass index, ferritin, d-dimer, APACHE II score, SOFA score, blood gas, ventilation mode and settings Patients with evidence of barotrauma (pneumothorax, pneumomediastinum, pneumopericardium, subcutaneous emphysema) on imaging had additional respiratory data points collected RESULTS: 78 patients met inclusion Among 38 patients who received invasive mechanical ventilation (IMV) 12 had barotrauma (32%) Of 40 patients who did not receive IMV 3 had barotrauma (8%) Of 15 cases of barotrauma, 8 had pneumothorax (2 bilateral, 6 unilateral), 9 had pneumomediastinum, 4 had pneumopericardium, 6 had subcutaneous emphysema 8 were found incidentally on imaging for non-respiratory indication Mortality in the barotrauma group was 72% for IMV & 50% for non-IMV (3 patients transferred to other hospital, 3 remain hospitalized) compared to 50% for IMV & 8% for non-IMV in patients without barotrauma Further analysis pending at submission, data to be finalized prior to presentation CONCLUSIONS: Barotrauma may be an underappreciated complication of COVID-19, perhaps serving as an independent predictor of disease severity or low lung compliance Many theories have been presented for the physiology of COVID-19 respiratory failure, but barotrauma could be evidence of or a herald sign for the low compliance phenotype

Background: Interleukin (IL)-6 signalling has been implicated in allergic asthma by animal, genetic association and clinical studies. In this study, we tested the hypothesis that tocilizumab (TCZ), a human monoclonal antibody that blocks IL-6 signalling, can prevent the development of allergen-induced bronchoconstriction in humans. Methods: We performed a randomised, double-blind, placebo-controlled study, with eligible participants completing two allergen inhalation challenge tests, conducted before and after treatment with a single dose of TCZ or placebo. The primary efficacy endpoint was the magnitude of the late asthmatic response recorded between 3 and 7 after allergen challenge. The secondary efficacy endpoint was the early asthmatic response, measured 20 min to 2 h after allergen challenge. Results: A total of 66 patients enrolled between September 2014 and August 2017, when the trial was stopped for futility based on results from an interim analysis. Eleven patients fulfilled all eligibility criteria assessed at baseline and were subsequently randomised to the TCZ (n = 6) or placebo (n = 5) groups. Both the primary and secondary efficacy endpoints were not significantly different between the two groups. Five patients reported adverse events (AEs), three in the TCZ group (11 AEs) and two in the placebo group (four AEs). Only one AE was TCZ-related (mild neutropenia), and there were no serious AEs. Significant treatment effects were observed for serum levels of C-reactive protein, IL-6 and soluble IL-6R levels. Conclusion: In a small proof-of-concept clinical trial, we found no evidence that a single dose of tocilizumab was able to prevent allergen-induced bronchoconstriction. (Trial registered in the Australian New Zealand Clinical Trials Registry, number ACTRN12614000123640).

Background Cough is a common and troublesome symptom in asthmatic patients, but little is known about the neuronal pathways that trigger cough. The mechanisms by which airway inflammation, airway hyperresponsiveness, and variable airflow obstruction cause cough are unclear. Objective We sought to investigate the effects of allergen exposure on cough reflex sensitivity. Methods We performed a 9-visit, randomized, single-blind, placebo-controlled, 2-way crossover study comparing cough responses to inhaled capsaicin in patients with mild atopic asthma after allergen challenge compared with diluent control. Full-dose capsaicin challenge was performed at screening to determine the capsaicin dose inducing a half-maximal response, which was subsequently administered at 30 minutes and 24 hours after inhaled allergen/diluent challenge. Spontaneous coughing was measured for 24 hours after allergen/diluent. Methacholine challenge and sputum induction were performed before and after allergen/diluent challenge. Results Twelve steroid-naive subjects completed the study (6 female subjects; mean age, 34.8 years). Allergen inhalation caused both an early (mean ± SD, 38.2% ± 13.0%) and late (mean ± SD, 23.7% ± 13.2%) decrease in FEV1 and an increase in sputum eosinophil counts 24 hours later (after diluent: median, 1.9% [interquartile range, 0.8% to 5.8%]; after allergen: median, 14.9% [interquartile range, 8.9% to 37.3%]; P = .005). There was also an increase in capsaicin-evoked coughs after allergen exposure compared with diluent at both 30 minutes (geometric mean coughs, 21.9 [95% CI, 16.5-29.20] vs 12.1 [95% CI, 8.3-17.7]; P Conclusion Allergen-induced bronchoconstriction and airway eosinophilia result in increased cough reflex sensitivity to capsaicin associated with an increase in 24-hour spontaneous coughing.

BACKGROUND: An unresolved issue in T regulatory (Treg) cell biology is the lack of consensus on phenotypic markers that accurately define the natural Treg (nTreg) population. OBJECTIVES: To examine nTreg frequency and functional capacity in healthy controls, and their frequency in asthmatic subjects using three different phenotypic strategies. We hypothesized that phenotypically different nTreg are quantitatively and functionally different. METHODS: 34 healthy, non-asthmatic and 17 asthmatic subjects were studied. Three nTreg phenotypes were defined: nTreg1 (CD4(+) CD25(+) Foxp3(+) ), nTreg2 (CD4(+) CD25(+) CD127(low) Foxp3(+) ), and nTreg3 (CD4(+) CD25(high) Foxp3(+) ). The flow cytometric determination of nTreg frequency in peripheral blood (PB) and bronchoalveolar lavage (BAL) was performed using fluorescently labelled antibodies. PB nTreg functional capacity was assessed using a CFSE-based suppression assay. RESULTS: There was a significantly lower frequency of peripheral blood nTreg3 compared to nTreg2 and nTreg1 (p

OX40-OX40L interactions and thymic stromal lymphopoietin (TSLP) are important in the induction and maintenance of Th2 responses in allergic disease, whereas T regulatory cells (Treg) have been shown to suppress pro-inflammatory Th2 responses. Both OX40L and TSLP have been implicated in the negative regulation of Treg. The effect of anti-asthma therapies on Treg is not well known. Our aim was to assess the effects of two monoclonal antibody therapies (anti-OX40L and anti-TSLP) on Treg frequency using a human model of allergic asthma. We hypothesized that the anti-inflammatory effects of these therapies would result in an increase in circulating Treg (CD4(+) CD25(+) CD127(low) Foxp3(+) cells) frequency. We measured Treg using flow cytometry, and our results showed that neither allergen challenge nor monoclonal antibody therapy altered circulating Treg frequency. These data highlight the need for assessment of airway Treg and for a more complete understanding of Treg biology so as to develop pharmacologics/biologics that modulate Treg for asthma therapy.

Effective antiinflammatory therapies are needed for the treatment of asthma, but preferably without the systemic adverse effects of glucocorticosteroids.We evaluated the effect of an inhaled nonsteroidal glucocorticoid receptor agonist, AZD5423, on allergen-induced responses.Twenty subjects with mild allergic asthma were randomized to receive 7 days of treatment with nebulized AZD5423 (75 or 300 μg) once daily, budesonide 200 μg twice daily via Turbuhaler, or placebo in a double-blind, four-period, crossover design study. Allergen challenge was performed on Day 6.FEV1 was measured repeatedly for 7 hours after allergen challenge for early and late asthmatic responses. Sputum inflammatory cells was measured before and at 7 and 24 hours after allergen challenge, and methacholine airway responsiveness was measured before and 24 hours after allergen challenge. AZD5423 significantly attenuated the fall in FEV1 during the late asthmatic response (both doses led to an 8.7% fall) versus placebo (14% fall) (P 0.05) with no effect of budesonide (12.5% fall) versus placebo (P 0.05). There was no effect on the fall in FEV1 during early asthmatic response. AZD5423 300 and 75 μg significantly attenuated allergen-induced sputum eosinophilia by 63 and 61% at 7 hours, respectively, and by 46 and 34% at 24 hours after allergen challenge, respectively, versus placebo (all P 0.05). Budesonide did not reduce allergen-induced sputum eosinophilia versus placebo. AZD5423 at 300 μg significantly attenuated allergen-induced airway hyperresponsiveness at 24 hours after allergen challenge versus placebo (P 0.05). Both doses of AZD5423 were well tolerated.Seven-day treatment with inhalation of the nonsteroidal glucocorticoid receptor agonist AZD5423 effectively reduced allergen-induced responses in subjects with mild allergic asthma. Clinical trial registered with www.clinicaltrials.gov (NCT01225549).

The latest methacholine challenge testing (MCT) guidelines published by the European Respiratory Society recommend the characterization of nebulizers before their use in clinics and research. Such investigations are necessary for accurately determining the provocative dose of methacholine causing a 20% fall in FEVSixty mild-to-moderate asthmatics were studied across three research sites in a randomized crossover study. Both methacholine challenges were completed at least 24 hours apart within a 2-week period. Testing with the Wright device was performed as per the 2-minute tidal breathing protocol. The Solo study arm followed the same procedure except for a shorter inhalation time of 1 minute. The provocative concentration of methacholine causing a 20% fall in FEVThe geometric mean methacholine PCThe comparability of PD

BACKGROUND: Dendritic cells (DCs) are professional antigen-presenting cells that mediate the response to inhaled allergen. A major division in DC ontogeny exists between myeloid DCs (mDCs) and plasmacytoid DCs (pDCs). A subtype of mDC expressing thrombomodulin, termed myeloid DCs type 2 (mDC2s), has been identified in both the circulation and lung and has recently been suggested to have a role in allergic asthma. OBJECTIVE: To investigate changes in circulating and sputum mDC2s after allergen inhalation in subjects with asthma. METHODS: Peripheral blood and induced sputum were obtained before and 3, 7, and 24�h after inhalation of diluent and allergen from allergic asthmatic subjects who develop both allergen-induced early- and late-phase responses. mDC2s were measured by flow cytometry. Soluble BDCA-3 (thrombomodulin) was measured in sputum by ELISA. RESULTS: The number of sputum mDC2s significantly increased 24�h after allergen challenge compared with diluent. The expression of BDCA-3 on sputum mDCs also increased, albeit non-significantly, at 7 and 24�h after allergen. Soluble BDCA-3 in sputum and the number of circulating mDC2s were not different between allergen and diluent. CONCLUSIONS AND CLINICAL RELEVANCE: Myeloid DCs type 2 (mDC2s) increase in the sputum of subjects with asthma after allergen challenge, suggesting this subtype of mDC is involved in the regulation of allergen responses in the lung.

Peroxisome proliferator-activated receptor (PPAR) agonists have been suggested as novel therapeutics for the treatment of inflammatory lung disease, such as allergic asthma. Treatment with PPAR agonists has been shown to inhibit airway eosinophilia in murine models of allergic asthma, which can occur through several mechanisms including attenuated generation of chemoattractants (e.g. eotaxin) and decreased eosinophil migrational responses. In addition, studies report that PPAR agonists can inhibit the differentiation of several cell types. To date, no studies have examined the effects of PPAR agonists on interleukin-5 (IL-5) -induced eosinophil differentiation from haemopoietic progenitor cells. Non-adherent mononuclear cells or CD34+ cells isolated from the peripheral blood of allergic subjects were grown for 2 weeks in Methocult® cultures with IL-5 (10 ng/ml) and IL-3 (25 ng/ml) in the presence of 1–1000 nm PPARα agonist (GW9578), PPARβ/δ agonist ({"type":"entrez-nucleotide","attrs":{"text":"GW501516","term_id":"289075981","term_text":"GW501516"}}GW501516), PPARγ agonist (rosiglitazone) or diluent. The number of eosinophil/basophil colony-forming units (Eo/B CFU) was quantified by light microscopy. The signalling mechanism involved was assessed by phosphoflow. Blood-extracted CD34+ cells cultured with IL-5 or IL-5 + IL-3 formed Eo/B CFU, which were significantly inhibited by rosiglitazone (100 nm, P < 0·01) but not GW9578 or {"type":"entrez-nucleotide","attrs":{"text":"GW501516","term_id":"289075981","term_text":"GW501516"}}GW501516. In addition, rosglitazone significantly inhibited IL-5-induced phosphorylation of extracellular signal-regulated kinase 1/2. We observed an inhibitory effect of rosiglitazone on eosinophil differentiation in vitro, mediated by attenuation of the extracellular signal-regulated kinase 1/2 signalling pathway. These findings indicate that the PPARγ agonist can attenuate tissue eosinophilia by interfering with local differentiative responses.

Summary Background TPI ASM8 contains two modified phosphorothioate antisense oligonucleotides (AON), one targeting the common beta chain (βc) of the IL-3/IL-5/GM-CSF receptors and the other targeting the chemokine receptor CCR3. Inhalation of TPI ASM8 significantly improves lung function and sputum eosinophilia after allergen inhalation challenge in asthmatics. Objective This study assessed whether TPI ASM8 reduces airway levels of haemopoietic progenitor cells. Methods This open-label study was conducted in 14 stable, allergic mild asthmatic subjects with early- and late-phase allergen-induced bronchoconstriction. Subjects underwent allergen challenges after 4-day treatment with placebo, 4 mg b.i.d. and 8 mg o.d. of TPI ASM8. Sputum was induced before, 7 and 24 h after allergen challenges for progenitor measurements. Treatments were separated by 2–3 weeks. Results TPI ASM8 reduced allergen-induced sputum eosinophils, and the early and late asthmatic responses (P

Summary Background Smoking asthmatics experience more severe symptoms, require more rescue medication and have more asthma-related hospitalizations than non-smoking asthmatics. However, studies in mice suggest that mainstream cigarette smoke may reduce airway inflammation and may attenuate airway hyperresponsiveness. A comparison of allergen-induced airway inflammatory responses of smoking and non-smoking atopic asthmatics has not been examined previously. Objectives To determine whether allergen-induced airway responses and inflammatory profiles are attenuated in smoking when compared with non-smoking mild allergic asthmatic subjects. Methods Allergen inhalation challenges were performed in 13 smoking and 19 non-smoking mild allergic asthmatic subjects. The forced expired volume in 1 s (FEV1) was measured up to 7 h after allergen inhalation. Methacholine airway responsiveness was measured before and at 24 h after allergen and sputum was induced before and at 7 and 24 h after allergen. Results Both the smoking and non-smoking groups developed similar allergen-induced falls in FEV1 during the early and late asthmatic responses and similar increases in allergen-induced airway eosinophils. The mean maximum fall in FEV1 during the late response was 16.3±4.3% in non-smokers and 12.9±7.2% in smokers. The smoking asthmatics, however, did not develop allergen-induced methacholine airway hyperresponsiveness, whereas the non-smoking controls developed a 1.18 doubling dose shift in methacholine PC20 (P

To cite this article: Gauvreau GM, Pageau R, Seguin R, Carballo D, Gauthier J, D’Anjou H, Campbell H, Watson R, Mistry M, Parry-Billings M, Killian K, Renzi PM. Dose–response effects of TPI ASM8 in asthmatics after allergen. Allergy 2011; 66: 1242–1248. Abstract Background: TPI ASM8 contains two modified antisense oligonucleotides (AON) targeting the beta subunit (βc) of the IL-3, IL-5, GM-CSF receptors and the chemokine receptor CCR3. A previous study suggested that TPI ASM8 had broader effects than just inhibition of eosinophils in asthmatics. Objective: We assessed whether TPI ASM8 caused a dose-dependent attenuation in the inflammatory and physiological changes after inhaled allergen challenge (AIC). Methods: This single-center, open-label, stepwise-ascending dose study was conducted in fourteen stable, mild allergic asthmatics. Following placebo AIC, subjects underwent AIC after 4 days treatment with 1, 2, and 4 mg BID and finally 8 mg once daily (OD) of TPI ASM8, inhaled via the I-Neb™ nebuliser. Treatments were separated by 2–3-week washout periods. Results: TPI ASM8 was safe and well tolerated at all doses. TPI ASM8 8 mg OD reduced eosinophils in sputum after AIC (by 60.9% at 7 h and 68.4% at 24 h post-AIC, P = 0.016 and P = 0.007, respectively). Additionally, TPI ASM8 8 mg OD significantly attenuated the early and late airway responses as shown by the reduction in the area under the curve by 45% (P = 0.016) and 59%, (P = 0.0015), respectively, the increase in eosinophil cationic protein (ECP) by up to 57% (P = 0.021), and airway responsiveness to methacholine by more than 1 doubling dose (P = 0.012). A dose–response relationship was noted, and efficacy was maintained with once per day administration. Conclusions: TPI ASM8 attenuated a broad range of inflammatory and physiological changes after AIC, suggesting that CCR3, IL-3, and GM-CSF also are important targets for the management of asthma.

To cite this article: Imaoka H, Gauvreau GM, Watson RM, Strinich T, Obminksi GL, Howie K, Killian KJ, O’Byrne PM. Sputum inflammatory cells and allergen-induced airway responses in allergic asthmatic subjects. Allergy 2011; 66: 1075–1080. Abstract Background: Allergen inhalation causes early and late bronchoconstrictor responses, airway hyperresponsiveness and airway inflammation in allergic asthmatics. The role of airway inflammatory cells in causing allergen-induced bronchoconstriction and airway hyperresponsiveness is controversial. The objective of this study was to examine the relationships between allergen-induced increases in airway inflammatory cells, early and late bronchoconstrictor responses and methacholine airway hyperresponsiveness. Methods: Allergen inhalation challenge was conducted in 50 allergic asthmatics. Changes in the forced expired volume in 1 s (FEV1%) were followed for 7 h, induced sputum was obtained at 7 and 24 h, and the provocative concentration of methacholine causing a 20% fall in FEV1 (MCh PC20) was measured at 24 h. Results: There was a significant negative correlation between the baseline methacholine PC20 and baseline sputum eosinophils (r = −0.512, P = 0.0001). Allergen-induced changes in methacholine PC20 were also significantly negatively correlated to allergen-induced change in sputum eosinophils at 24 h (r = −0.434, P = 0.002), but not to changes in any other inflammatory cells. There were no significant correlations between sputum eosinophils or other inflammatory cells and the allergen-induced early or late asthmatic responses. Conclusion: Allergen-induced increases in airway eosinophils in asthmatic dual responders may contribute to allergen-induced changes in methacholine PC20, but not the late asthmatic responses.

BACKGROUND: Dendritic cells are professional antigen presenting cells that mediate the response to inhaled allergens. In animal models, the induction and maintenance of allergic airway inflammation is primarily a function of myeloid dendritic cells, whereas the tolerization to inhaled allergens is likely a function of plasmacytoid dendritic cells. OBJECTIVE: To investigate changes in sputum myeloid and plasmacytoid dendritic cells after allergen inhalation in subjects with asthma. Also, the number of myeloid and plasmacytoid dendritic cells expressing both CCR6 and 7 and their chemokine ligands macrophage inflammatory protein (MIP)-3alpha and 3beta were measured in sputum supernatants. METHODS: Sputum was induced from 12 dual-responder subjects with allergic asthma before and 7 hours, 24 hours, and 72 hours after inhalation of diluent and allergen. Dendritic cells were enumerated via flow cytometry and the chemokines by using ELISAs. RESULTS: The number of sputum myeloid dendritic cells was significantly higher 24 hours after allergen challenge compared with diluent. Similarly, sputum plasmacytoid dendritic cells increased significantly at 24 hours after allergen challenge. Also, a significant increase in CCR6(+) myeloid dendritic cells numbers occurred 72 hours after allergen challenge. In contrast, CCR7(+) myeloid dendritic cells, as well as the number of CCR6(+) and CCR7(+) plasmacytoid dendritic cells, were not different between challenges. Finally, allergen challenge increased sputum levels of MIP-3alpha, but not MIP-3beta, compared with baseline. CONCLUSIONS: Both myeloid and plasmacytoid dendritic cells increase in the sputum of subjects with asthma after allergen challenge, suggesting that both subsets are involved in the pathogenesis of allergen responses in asthma.

Charge transfer studies have been performed for self-assembled monolayers of single-stranded and double-stranded peptide nucleic acids (PNAs) having a C-terminus cysteine and an N-terminus ferrocene group as a redox reporter. The decay of the charge transfer rate with distance was strong for short single-stranded PNA molecules and weak for long single-stranded and double-stranded PNAs. Possible mechanisms for this "softening" of the distance dependence are discussed. The nature of the mechanism change can be explained by a transition of the charge transport mechanism from superexchange-mediated tunneling for short PNAs to a "hopping" mechanism for long PNAs.

Montelukast and desloratadine synergistically inhibit the allergen-induced early asthmatic response. Montelukast also suppresses the allergen-induced late asthmatic response, but there are no reports on the effect of desloratadine or the combination on the allergen-induced late asthmatic response. Atopic asthmatics (n = 10) completed a multicentric randomised double-blind crossover study comparing single-dose placebo, 5 mg desloratadine, 10 mg montelukast and the combination administered 2 h prior to allergen inhalation challenge. Methacholine challenges were performed 24 h before and after allergen challenge. Exhaled nitric oxide measurements and sputum inflammatory cell counts were also carried out. All active treatments significantly decreased the late asthmatic response area under the curve. Combination therapy provided the greatest inhibition compared to desloratadine and montelukast. Montelukast was nonsignificantly better than desloratadine but not as effective as the combination. There was a trend towards a decrease in airway responsiveness following montelukast and combination. Montelukast, but not desloratadine or the combination, decreased exhaled NO levels 24 h after allergen. The allergen-induced increase in sputum eosinophil numbers was significantly suppressed at 7 h with desloratadine and combination therapy, and at 24 h with montelukast and combination therapy. Single-dose co-administration of desloratadine and montelukast 2 h prior to allergen inhalation clinically abolished the late asthmatic response and eosinophil recruitment.

The drug product TPI ASM8 contains two modified phosphorothioate antisense oligonucleotides designed to inhibit allergic inflammation by down-regulating human CCR3 and the common beta chain (beta(c)) of IL-3, IL-5, and granulocyte-macrophage colony-stimulating factor receptors.This study examined the effects of inhaled TPI ASM8 on sputum cellular influx, CCR3 and beta(c) mRNA and protein levels, and the airway physiologic response after inhaled allergen.Seventeen subjects with mild atopic asthma were randomized in a crossover study to inhale 1,500 microg TPI ASM8 or placebo by nebulizer, once daily for 4 days. On Day 3, subjects underwent allergen inhalation challenge. Sputum samples were collected before and after allergen. CCR3 and beta(c) protein levels were measured by flow cytometry, mRNA was measured using real-time quantitative polymerase chain reaction, and the FEV1 was measured over 7 hours after challenge.Compared with placebo, TPI ASM8 inhibited sputum eosinophil influx by 46% (P = 0.02) and blunted the increase in total cells (63%) after allergen challenge. TPI ASM8 significantly reduced the early asthmatic response (P = 0.04) with a trend for the late asthmatic response (P = 0.08). The allergen-induced (Day 2 to Day 3) levels of beta(c) mRNA and CCR3 mRNA in sputum-derived cells were inhibited by TPI ASM8 (P = 0.039 and P = 0.054, respectively), with no significant effects on the cell surface protein expression of CCR3 and beta(c) (P0.05). No serious adverse events were reported.TPI ASM8 attenuates the allergen-induced increase in target gene mRNA and airway responses in subjects with mild asthma. Clinical trial registered with www.clinicaltrials.gov (NCT 00264966).

Self-assembled monolayers (SAMs) of single-stranded peptide nucleic acids (PNAs) containing 3 to 7 thymine (T) nucleotides, a C-terminus cysteine, and an N-terminus ferrocene group were formed on gold electrodes. The existence of two redox environments for the ferrocene was detected by cyclic voltammetry and was attributed to the presence of “lying-down” and “standing-up” PNA molecules. By exploiting the chemical instability of the ferrocenium ion, electrochemical cycling was used to destroy the ferrocene of “lying-down” molecules while keeping the ferrocene in the “standing-up” molecules intact. Electrochemical measurements were used to determine the electron-transfer rate through the “standing-up” PNA molecules. The tunneling decay constant for these SAMs was determined to be about 0.9 A-1.

Background: Dendritic cells are key contributors to initiation and maintenance of T-cell immunity to inhaled allergen. The purpose of this study was to enumerate the changes in peripheral blood myeloid (mDCs) and plasmacytoid dendritic cells (pDCs), the DCs expressing chemokine receptor 6 (CCR6) and chemokine receptor 7 (CCR7), following diluent and allergen inhalation in asthmatic subjects. Methods: Peripheral blood was obtained from 16 allergic asthmatic subjects before and at 0.5, 1, 2, 3, 4, 6, 24, and 48 h after inhaled diluent and allergen challenges. Dendritic cells were enumerated using flow cytometry. Results: Allergen inhalation significantly reduced mDCs at 6 h (21.3 ± 2.0 vs 15.0 ± 1.8/μl blood; P

Background The use of combination inhaled budesonide and formoterol as maintenance and reliever therapy significantly improves the risk and the time to exacerbations in asthma. Objectives To explore the mechanisms underlying the effect of the reliever dose on exacerbations by examining the effect of combination therapy on the allergen challenge model when given after allergen exposure. Methods In a randomized, double-blind crossover study, single doses of budesonide/formoterol (400/12 μg), formoterol (12 μg), budesonide (400 μg), or placebo were administered during the acute bronchoconstriction response (early airway response) immediately after allergen inhalation in 15 patients with mild asthma. Allergen-induced late airway response (LAR), sputum inflammatory markers, airway hyperresponsiveness, and exhaled nitric oxide were measured. Results All active treatments significantly attenuated the LAR, with budesonide/formoterol significantly better than its monocomponents (maximum FEV 1 fall: placebo, [mean ± SEM] 21.2% ± 3.1%; budesonide/formoterol, 4.2% ± 1.4%; formoterol, 7.5% ± 1.7%; budesonide, 10.4% ± 1.6%). Allergen-induced change in methacholine PC 20 was significantly attenuated by budesonide/formoterol, but not by its monocomponents. Sputum cell counts and exhaled nitric oxide increased significantly after all allergen challenges, with no significant attenuation by any of the treatments. Therapy with combination and formoterol alone, but not budesonide, significantly reduced the early airway response. Conclusion A single dose of budesonide/formoterol was superior to its monocomponents in attenuating the allergen-induced LAR and airway hyperresponsiveness. These effects may represent the contribution of the reliever dose to the budesonide/formoterol maintenance and reliever regimen. Clinical implications The protective effect against allergic airway responses with a single reliever dose of budesonide/formoterol is predominantly related to greater functional antagonism of airway smooth muscles.

Aim: QGE031 is a high-affinity humanized anti-IgE antibody in development for treatment of uncontrolled severe asthma. We predicted steady-state dose responses by fitting a mathematical model to PKPD data. Methods: Subjects with mild, atopic asthma (N=37) were randomised to 3 s.c. doses (240mg,N=8; 72mg,N=8; 24mg,N=8) of QGE031 every 2 weeks (wks) for 12wks, Omalizumab (OMA) (N=6; US dosing table) or placebo (N=7). Allergen challenges were conducted 6, 12 and 18 wks after the first dose. Mathematical functions were fitted to full time course drug, total IgE and basophil data. After curve fitting, 0-6 month responses of ∼1000 patients, each receiving an array of 4 wkly administrations of QGE031 (0-1200mg) and OMA (US dosing table), were simulated. Results: The model fitted the response data, down regulation of basophil FceR1 and surface IgE, and inhibition of bronchial and skin allergen reactivity from subjects treated with QGE031 and OMA. QGE031 36mg, dosed every 4 wks, was predicted to give similar skin wheal and allergen PC15 responses to OMA. Higher doses of QGE031 would be required for patients with higher baseline IgE. Conclusion: QGE031 is more effective than OMA in inhibiting bronchial and skin allergen response in a clinical setting. This mathematical model could allow better planning and prediction of future trial outcomes.

BACKGROUND: The predominance of T-helper type 2 (Th2) lymphocytes is thought to underlie the pathogenesis of asthma. Allergen inhalation challenge in atopic asthmatic subjects is associated with decreased interferon-gamma (IFN-gamma) positive CD4+ and CD8+ lymphocytes in peripheral blood and induced sputum. OBJECTIVE: This study examined the effects of an inhaled corticosteroid on these previously described allergen-induced changes in circulating Th1 and Th2 lymphocytes. METHODS: Subjects were randomized to 7 days of placebo, 40 or 80 micro g ciclesonide in a crossover study. Airway responses and peripheral blood were measured before and after treatment, and 24 h after allergen challenge. RESULTS: Ciclesonide 40 and 80 micro g significantly attenuated the late response and sputum eosinophils at 8 h post-allergen (P

Substitution of natural nucleobases in PNA oligomers with ligands is a strategy for directing metal ion incorporation to specific locations within a PNA duplex. In this study, we have synthesized PNA oligomers that contain up to three adjacent bipyridine ligands and examined the interaction with Ni2+ and Cu2+ of these oligomers and of duplexes formed from them. Variable-temperature UV spectroscopy showed that duplexes containing one terminal pair of bipyridine ligands are more stable upon metal binding than their nonmodified counterparts. While binding of one metal ion to duplexes that contain two adjacent bipyridine pairs makes the duplexes more stable, additional metal ions lower the duplex stability, with electrostatic repulsions being, most likely, an important contributor to the destabilization. UV titrations showed that the presence of several bipyridine ligands in close proximity of each other in PNA oligomers exerts a chelate effect. A supramolecular chelate effect occurs when several bipyridines are brought next to each other by hybridization of PNA duplexes. EPR spectroscopy studies indicate that even when two Cu2+ ions coordinate to a PNA duplex in which two bipyridine pairs are next to each other, the two metal-ligand complexes that form in the duplex are far enough from each other that the dipolar coupling is very weak. EXAFS and XANES show that the Ni2+-bipyridine bond lengths are typical for [Ni(bipy)2]2+ and [Ni(bipy)3]2+ complexes.

Background: Inhalation of allergens by sensitized patients with asthma induces reversible airway obstruction, airway hyperresponsiveness, and eosinophilic airway inflammation. Attenuation of allergen-induced bronchoconstriction and inflammation has been used to examine the efficacy of therapeutic agents such as inhaled corticosteroids in asthma. Ciclesonide, a nonhalogenated inhaled corticosteroid being developed for the treatment of persistent asthma, remains inactive until cleaved by esterases in the lung.Objective: This study examined the effect of low doses of inhaled ciclesonide, 40 Kg and 80 mu g, on allergen-induced bronchoconstriction, serum eosinophil cationic protein, and eosinophilic airway inflammation.Methods: Twenty-one nonsmokers with mild atopic asthma completed a multicenter, randomized, 3-way crossover study comparing the effects of 7-day treatment of ciclesomide or placebo. Allergen-induced responses, including the early and late fall in FEV1, peripheral blood eosinophils, serum eosinophil cationic protein levels, and eosinophils in induced sputum were measured.Results: Ciclesonide 80 jig attenuated the early and late asthmatic responses, including the change in FEV1, serum eosinophil cationic protein, and sputum eosinophils measured at 24 hours postchallenge (P Conclusion: With the exception of 24-hour postchallenge peripheral blood eosinophils, a low dose of ciclesonide, 80 mu g, was effective in blocking all allergen-induced responses measured.

Background Treatment with inhaled steroids is an effective method of reducing bronchoconstriction and airway inflammation after allergen challenge. However, the durationof the protective effects of inhaled steroids after discontinuation of therapy has not been established. Objective We sought to evaluate the protective effect of 1 week of inhaled steroid therapy against inhaled allergen challenge 12 hours after discontinuation of therapy. Methods In this randomized, double-blind, placebo-controlled crossover trial, 26 asthmatic subjects (>18 years old) not using inhaled steroids were administered 200 μg of budesonide twice daily, 200 μg of fluticasone twice daily, or placebo twice daily for 1 week. Twelve hours after discontinuation of therapy, subjects were administered an inhaled allergen challenge. Each treatment period was separated by a 3-week washout period. Results When compared with placebo (26% ± 14%), there was a slight but significant protection against the allergen-induced early response after fluticasone treatment (19% ± 10%, P =.001) but not after budesonide treatment (23% ± 13%, P =.08). However, when the area under the curve for the early airway response was examined, there was no difference between the 2 drugs in the amount of protection ( P =.62). Partial protection was demonstrated against the late-response allergen-induced sputum eosinophilia with both treatments ( P =.001). By contrast, no protection was observed against allergen-induced airway hyperresponsiveness for either treatment. Conclusions The protective effects of inhaled steroids against allergen-induced early responses, airway eosinophilia, and allergen-induced airway hyperresponsiveness are partially or completely lost as early as 12 hours after discontinuation of therapy.

Background CCR3 expression on CD34 + cells mediates migration to eotaxin in vitro . CXCR4 and stromal cell–derived factor (SDF)–1α are important for stem cell homing to hemopoietic compartments. Objective To study chemokine-mediated progenitor cell traffic in allergic inflammation. Methods Bone marrow (BM) aspirates were obtained at baseline from normal subjects; atopic subjects without asthma; and subjects with asthma before, 5 hours after, and 24 hours after allergen inhalation (dual and early responders). Changes in chemokine receptor expression and migration were assessed. Results Expression of CXCR4, but not CCR3, on BM CD34 + cells was greater in normal subjects compared with atopic subjects with asthma. Likewise, SDF-1α, but not eotaxin, stimulated a greater migrational response by BM CD34 + cells from normal subjects compared with subjects with asthma. For all subjects, a positive correlation was found between intensity of CXCR4 expression and magnitude of CD34 + cell response to SDF-1α. Allergen inhalation attenuated both intensity of CXCR4 expression and SDF-1α levels in marrow from dual compared with early responders 24 hours postallergen. In contrast, the intensity of CCR3 expression on BM CD34 + cells increased in dual compared with early responders at 24 hours postallergen. In addition, an increase in migrational responsiveness of BM CD34 + cells to eotaxin and a decrease to SDF-1α 24 hours postallergen was found in dual responder subjects with asthma. Conclusion After allergen inhalation in subjects with asthma, a downregulation in CXCR4 intensity on BM CD34 + cells and a reduction in BM SDF-1α levels may reduce progenitor retention to marrow stroma promoting peripheral egress, possibly mediated by the CCR3/eotaxin axis.

Background Dendritic cells are important antigen-presenting cells. After an allergen inhalation, their numbers rapidly decrease in circulation and increase in the airway mucosa. Objective To investigate whether allergen-induced changes in the number of circulating dendritic cells are mediated by cysteinyl leukotrienes. Methods In a randomized, double-blind, crossover study, we examined the effects of 2 weeks of treatment with pranlukast (a cysteinyl leukotriene 1 [CysLT 1 ] receptor antagonist) 300 mg twice daily and placebo on allergen-induced changes in airway responses and circulating dendritic cells in 15 subjects with mild asthma. We examined by flow cytometry, before and at 3 hours and 24 hours after allergen inhalation, the proportion of myeloid (CD33 + ) and plasmacytoid (CD123 + ) dendritic cells (HLA-DR + , CD14 – , CD16 – ) among all peripheral blood mononuclear cells. The fraction of dendritic cells expressing CysLT 1 receptor was also determined. Results Compared with placebo, pranlukast significantly attenuated both the maximum early (by 55%) and the late (by 39%) asthma responses, the allergen-induced methacholine airway hyperresponsiveness, and the increase in macrophage inflammatory protein 1α and 3α in induced sputum. A significantly greater proportion of CD33 + cells (55%) expressed CysLT 1 receptor compared with CD123 + cells (11%). Consistent with this, pranlukast prevented the allergen-induced decrease in CD33 + dendritic cells at 3 hours postallergen (mean Δ from baseline, +4.4%) compared with placebo (mean Δ, −8.4; P + cells. Conclusion Pretreatment with pranlukast attenuated allergen-induced airway responses and the decrease in circulating myeloid dendritic cells, demonstrating a novel role of cysteinyl leukotrienes in dendritic cell trafficking.

Allergen inhalation is associated with increased eosinophil/basophil progenitors in bone marrow 24 hours after allergen inhalation. This study examined the kinetics of eosinophilopoiesis in dual (n = 14), compared with isolated early, responders (n = 12). Dual responders, in contrast to isolated early responders, develop significant sputum and blood eosinophilia and prolonged airway hyperresponsiveness. Bone marrow aspirates were taken before and 5, 12, 24, and 48 hours after allergen inhalation. In dual responders, increases in interleukin (IL)-3–responsive progenitors were detected as early as 5 hours after allergen inhalation, and IL-5–responsive progenitors were detected at 12 and 24 hours. No changes were detected in isolated early responders. Bone marrow IL-5 protein levels increased at 12 and 24 hours in dual responders only and these increases correlated with increases in IL-5–responsive progenitors. In addition, bone marrow IFN-γ levels increased in dual responders at 48 hours. These data demonst...

There is increasing evidence that primitive progenitors migrate from the bone marrow (BM) via the peripheral circulation to tissue sites where they undergo in situ differentiation to provide a continued source of effector cells, such as eosinophils, during an allergic inflammatory response. To study mechanisms of progenitor cell mobilization in allergic reactions, we investigated fluctuations in the expression of the eotaxin receptor, CC chemokine receptor 3 (CCR3), on CD34+ cells from stable asthmatics following allergen (i.e. antigen) challenge. BM aspirates were taken from seven early responder (ER) and 10 dual responder (DR) asthmatics who, following antigen challenge developed only an early bronchoconstrictor response and an early and late- bronchoconstrictor response, respectively. Expression of CCR3 was detected on primitive (CD34+ cells) and eosinophil-lineage committed progenitors (CD34+ interleukin-5 receptor alpha-subunit+ cells) by flow cytometry and confirmed by co-localization of CCR3 messenger RNA to CD34 immunopositive cells using in situ hybridization. When preantigen levels were compared to 24-hr postantigen levels, significant increases in BM CD34+ CCR3+ cells were detected in DR, who also developed a significant sputum and blood eosinophilia and increased methacholine airway responsiveness. In contrast, a significant attenuation of BM CD34+ CCR3+ cells was observed in ER. In a dose-dependent manner eotaxin, but not interleukin (IL)-5, stimulated CD34+ progenitor cell migration in vitro. This migrational response to eotaxin was abrogated by anti-CCR3 monoclonal antibody and primed by preincubation with IL-5. We propose that fluctuations in CCR3 expression on human BM CD34+ cells may facilitate chemokine-mediated progenitor cell mobilization to the peripheral circulation and the resultant development of pulmonary eosinophilia, a cardinal feature of asthma.

Inhaled corticosteroids are effective antiinflammatory therapy for asthma; however, they do not completely abolish allergen-induced airway inflammation. Leukotriene modifiers attenuate both early and late allergen responses and have antiinflammatory properties. We reasoned that treatment with budesonide and montelukast in combination might provide greater antiinflammatory effects than either drug alone, and the purpose of this study was to compare the effects of treatment with budesonide and montelukast, alone or in combination, on outcome variables after allergen inhalation. Ten subjects with asthma with dual responses after allergen inhalation were included in this randomized, double-blind, crossover study. Outcomes included early and late asthmatic responses, and changes in airway responsiveness and sputum eosinophilia, measured before and after challenge. Treatment with montelukast attenuated the maximal early asthmatic response compared with placebo (p < 0.001) and budesonide (p = 0.002). Both budesonide and montelukast, alone and in combination, attenuated the maximal late asthmatic response compared with placebo (p < 0.01). Budesonide and montelukast, alone and in combination, afforded protection against allergen-induced airway hyperresponsiveness (p < 0.05), although the treatment effect of budesonide was greater than that of montelukast (p < 0.05). Treatment with budesonide and montelukast, alone and in combination, also attenuated allergen-induced sputum eosinophilia. Thus, montelukast and budesonide attenuated allergen-induced asthmatic responses, airway hyperresponsiveness, and sputum eosinophilia, although combination treatment did not provide greater antiinflammatory effects than either drug alone.

Inhaled allergen challenge of subjects with atopic asthmatic increases bone marrow eosinophil progenitor cells. Interleukin-5 (IL-5) specifically induces growth and maturation of eosinophils. This study examined the effect of allergen challenge on the number of bone marrow total and CD3+ cells expressing IL-5 protein and IL-5 mRNA in subjects with asthma who developed either allergen-induced isolated early responses, or early and late asthmatic responses (dual responders). At 24 hours after allergen challenge, dual responders had significantly greater blood and airway eosinophilia compared with early responders. There were significant increases in the percentage of bone marrow CD3+ cells (p0.005) in both groups. However, there were significant differences in the increases in bone marrow IL-5 mRNA+ (p0.005), CD3+ (p0.005), and IL-5 mRNA+ CD3+ (p0.005) cells between the dual and early responder groups. These results suggest that, in subjects with atopic asthma, inhaled allergen causes trafficking of T lymphocytes to the bone marrow, and that in subjects who develop late responses and greater blood and airway eosinophilia after inhalation of allergen, there is a significant increase in the ability of bone marrow cells, particularly T lymphocytes, to produce IL-5.

BACKGROUND: Treatment with inhaled glucocorticosteroids attenuates allergen-induced airway inflammation but is less effective in people with asthma who have noneosinophilic airway inflammation.OBJECTIVE: Studies in which glucocorticosteroid treatment was used before allergen challenges were re-examined to determine whether the efficacy of steroid treatment could be predicted by baseline levels of sputum inflammatory cells.PATIENTS AND METHODS: Twenty-eight nonsmoking subjects with atopic asthma controlled by beta2-agonists participated in only one of three studies, each carried out with a double-blind, placebo controlled, randomized, crossover design. Subjects were treated with glucocorticosteroids or placebo for six to eight days and then underwent allergen inhalation challenge. Spirometry was measured for 7 h after allergen challenge, and then sputum inflammatory cells were measured. Sputum inflammatory cells were also measured before and after treatment, and 24 h after allergen challenge. The per cent inhibition of the allergen-induced airway responses by glucocorticosteroids was calculated.RESULTS: Inhaled gluticocorticosteroids significantly attenuated the early and late asthmatic responses, and the number of allergen-induced sputum eosinophils (PCONCLUSIONS: Baseline airway neutrophils, not eosinophils, can be used to predict the efficacy of inhaled steroids on allergen-induced sputum eosinophils.

To the Editors: The inflammatory process in allergic asthma is initiated by T-helper (Th) type-2 cells, which produce a repertoire of cytokines, including interleukin (IL)-4, IL-5, IL-9 and IL-13, which are necessary for immunoglobulin (Ig)E production, airway eosinophilia and goblet cell hyperplasia [1]. IL-18 is another pro-inflammatory cytokine, initially described as interferon (IFN)-γ-inducing factor [2]. IL-18 can act as a cofactor for Th2 cell development and IgE production [3]. Recently, an IL-18 gene polymorphism was reported to be associated with asthma severity and higher serum IL-18 levels: the rs5744247 variant, which has higher transcriptional activity than the wildtype allele [4]. In addition, the IL-18 receptor (IL-18R) gene (on 2q21) has been identified as a candidate gene associated with increased susceptibility to asthma in children [5], and polymorphisms of the gene have been associated with allergic asthma and airway hyperresponsiveness (AHR) [6]. We have evaluated serum levels of IL-18 and the expression of IL-18Rα, as well as other Th2-associated cytokines, in stable allergic asthmatic subjects, compared with allergic nonasthmatic subjects and healthy controls. We studied 36 subjects, which included 15 allergic asthmatic subjects, 11 nonasthmatic allergic subjects and 10 healthy controls (table 1). All subjects underwent a methacholine inhalation challenge [7] and had skin-prick tests to a panel of 16 environmental allergens. Total IgE, and serum IL-18, IL-4, IL-10, IL-12, IL-13 and IFN-γ were measured using commercially available ELISA kits (Medical and Biological Laboratories Co., Nagoya, Japan; RD DRG International Inc., Mountainside, NJ, USA). The allergic subjects were studied outside …