Efficacy and safety of multiple doses of QGE031 (ligelizumab) versus omalizumab and placebo in inhibiting allergen-induced early asthmatic responses.

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 FcεRI 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 FEV1 (allergen PC15) 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 PC15 (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.

The effects of a CXCR1/CXCR2 antagonist on neutrophil migration in mild atopic asthmatic subjects.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

A nonsteroidal glucocorticoid receptor agonist inhibits allergen-induced late asthmatic responses.

RATIONALE: Effective antiinflammatory therapies are needed for the treatment of asthma, but preferably without the systemic adverse effects of glucocorticosteroids. OBJECTIVES: We evaluated the effect of an inhaled nonsteroidal glucocorticoid receptor agonist, AZD5423, on allergen-induced responses. METHODS: 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. MEASUREMENTS AND MAIN RESULTS: 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. CONCLUSIONS: 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).

Effects of interleukin-13 blockade on allergen-induced airway responses in mild atopic asthma.

RATIONALE: Extensive evidence in animal models supports a role for IL-13 in the pathobiology of asthma. IMA-638 and IMA-026 are fully humanized IgG(1) antibodies that bind to different epitopes and neutralize IL-13 bioactivity. OBJECTIVES: We hypothesized that anti-IL-13 treatment would inhibit allergen-induced late-phase asthmatic responses, airway hyperresponsiveness, and inflammation in subjects with asthma. METHODS: Fifty-six subjects with mild, atopic asthma were recruited for two double-blind, randomized, placebo-controlled, parallel group trials to compare IMA-638 and IMA-026 IL-13 antibody treatments with placebo treatment. Drug was administered on Days 1 and 8, and allergen challenges were performed on Days 14 and 35. The primary outcome variable was the late-phase area under the curve (AUC), and secondary outcome variables were the early- and late-phase maximum percent fall in FEV(1), early AUC, allergen-induced shift in airway hyperresponsiveness, and sputum eosinophils. MEASUREMENTS AND MAIN RESULTS: The treatment difference with IMA-638 on Day 14 was -19.1 FEV(1) × hour (95% confidence interval: -36.2, -1.9) for the allergen-induced early AUC and -23.8 FEV(1) × hour (95% confidence interval: -46.4, -1.2) for the late AUC (both P < 0.05), but this effect was lost by Day 35. Treatment with IMA-026 did not attenuate the asthmatic responses on Day 14 or Day 35. There was no effect of either antibody on allergen-induced airway hyperresponsiveness or sputum eosinophils. The frequency of adverse events after administration of the IL-13 antibodies was similar to placebo. CONCLUSIONS: IL-13 has a role in allergen-induced airway responses in humans. Further study is required to determine whether anti-IL-13 monoclonal antibodies will be beneficial clinically.

Secondary structure prediction for RNA sequences including N6-methyladenosine.

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 N6-methyladenosine (m6A), allowing secondary structure prediction for an alphabet of A, C, G, U, and m6A. The RNAstructure software now works with user-defined nucleotide alphabets of any size. We also report a set of nearest neighbor parameters for helices and loops containing m6A, using experiments. Interestingly, N6-methylation decreases folding stability for adenosines in the middle of a helix, has little effect on folding stability for adenosines at the ends of helices, and increases folding stability for unpaired adenosines stacked on a helix. We demonstrate predictions for an N6-methylation-activated protein recognition site from MALAT1 and human transcriptome-wide effects of N6-methylation on the probability of adenosine being buried in a helix.

Roflumilast attenuates allergen-induced inflammation in mild asthmatic subjects.

BACKGROUND: Phosphodiesterase 4 (PDE4) inhibitors increase intracellular cyclic adenosine monophosphate (cAMP), leading to regulation of inflammatory cell functions. Roflumilast is a potent and targeted PDE4 inhibitor. The objective of this study was to evaluate the effects of roflumilast on bronchoconstriction, airway hyperresponsiveness (AHR), and airway inflammation in mild asthmatic patients undergoing allergen inhalation challenge. METHODS: 25 subjects with mild allergic asthma were randomized to oral roflumilast 500 mcg or placebo, once daily for 14 days in a double-blind, placebo-controlled, crossover study. Allergen challenge was performed on Day 14, and FEV1 was measured until 7 h post challenge. Methacholine challenge was performed on Days 1 (pre-dose), 13 (24 h pre-allergen), and 15 (24 h post-allergen), and sputum induction was performed on Days 1, 13, 14 (7 h post-allergen), and 15. RESULTS: Roflumilast inhibited the allergen-induced late phase response compared to placebo; maximum % fall in FEV1 (p = 0.02) and the area under the curve (p = 0.01). Roflumilast had a more impressive effect inhibiting allergen-induced sputum eosinophils, neutrophils, and eosinophil cationic protein (ECP) at 7 h post-allergen (all p = 0.02), and sputum neutrophils (p = 0.04), ECP (p = 0.02), neutrophil elastase (p = 0.0001) and AHR (p = 0.004) at 24 h post-allergen. CONCLUSIONS: This study demonstrates a protective effect of roflumilast on allergen-induced airway inflammation. The observed attenuation of sputum eosinophils and neutrophils demonstrates the anti-inflammatory properties of PDE4 inhibition and supports the roles of both cell types in the development of late phase bronchoconstriction and AHR. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01365533.

Myeloid and plasmacytoid dendritic cells in induced sputum after allergen inhalation in subjects with asthma.

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.

Prolonged bronchoprotection against inhaled methacholine by inhaled BI 1744, a long-acting beta(2)-agonist, in patients with mild asthma.

BACKGROUND: Long-acting ss(2)-agonists are an established controller medication in asthma. BI 1744 is a novel L\long-acting ss(2)-agonist with a preclinical profile that suggests 24-hour bronchodilation and bronchoprotection may be achieved. OBJECTIVE: To examine the bronchoprotective effects of single doses of BI 1744 against methacholine provocation in subjects with mild asthma. METHODS: Thirty-one subjects with mild asthma were randomized to receive single doses of BI 1744 (2, 5, 10, 20 microg) or placebo on separate days according to a double-blind, 5-way crossover design. Methacholine challenges were performed at 30 minutes and at 4, 8, 24, and 32 hours after each single dose of medication, and the results were expressed as PC(20) FEV(1). RESULTS: All doses of BI 1744 produced statistically significant increases in the methacholine PC(20) compared with placebo as long as 32 hours. The mean (geometric SEM) methacholine PC(20) 24 hours after dosing with placebo was 1.73 (1.13) mg/mL, which increased after 2 microg to 3.86 (1.14) mg/mL, after 5 microg to 5.67 (1.14) mg/mL, after 10 microg to 9.42 (1.13) mg/mL, and after 20 microg to 13.71 (1.14) mg/mL (all P < .0001). After 32 hours, the methacholine PC(20) value remained significantly increased for all doses. No safety or tolerability concerns were identified. CONCLUSION: BI 1744 provides significant bronchoprotection against inhaled methacholine for up to 32 hours after single-dose administration.

Antisense therapy against CCR3 and the common beta chain attenuates allergen-induced eosinophilic responses.

RATIONALE: 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. OBJECTIVES: 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. METHODS: 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. MEASUREMENTS AND MAIN RESULTS: 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) (P > 0.05). No serious adverse events were reported. CONCLUSIONS: 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).

Methacholine Challenge: Comparison of Airway Responsiveness Produced by a Vibrating Mesh Nebulizer Versus a Jet Nebulizer.

BACKGROUND: 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 FEV1 (PD20) delivered by a given device. The standard English Wright (Wright) jet nebulizer recommended in the 1999 guidelines by the American Thoracic Society has become difficult to obtain and possesses some characteristics that complicate the calculation of dose delivery from this device (e.g. evaporation). Our objective was to determine if the Aerogen® Solo (Solo) vibrating mesh nebulizer provides similar methacholine challenge test results compared to the currently used Wright jet nebulizer. METHODS: Sixty 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 FEV1 (PC20) and the methacholine PD20 were calculated following each methacholine challenge. RESULTS: The geometric mean methacholine PC20 values for the Solo and the Wright differed statistically (0.65 mg/mL vs. 2.58 mg/mL, respectively, p < 0.00001) and clinically. Between-nebulizer geometric mean methacholine PD20 results are comparable by clinical standards [81.7 µg (Solo) vs. 64.7 µg (Wright)], although the slight difference in dose was statistically significant (p = 0.018). CONCLUSIONS: The comparability of PD20 values between the Solo and the Wright validates the importance of reporting airway responsiveness to methacholine in terms of dose and not concentration, as stressed in the latest testing guidelines. This finding along with several benefits associated with the Solo make it a promising nebulizer for performing MCT.

RNA Secondary Structure Prediction.

In this unit, protocols are provided for predicting RNA secondary structure with the user-friendly RNAstructure desktop computer program and the RNAstructure Web server. The minimum free energy structure and a set of suboptimal structures with similar free energies are predicted. Prediction of high-affinity oligonucleotide binding sites to a structured RNA target is also presented. © 2016 by John Wiley & Sons, Inc.

Environmental health hazards of e-cigarettes and their components: Oxidants and copper in e-cigarette aerosols.

To narrow the gap in our understanding of potential oxidative properties associated with Electronic Nicotine Delivery Systems (ENDS) i.e. e-cigarettes, we employed semi-quantitative methods to detect oxidant reactivity in disposable components of ENDS/e-cigarettes (batteries and cartomizers) using a fluorescein indicator. These components exhibit oxidants/reactive oxygen species reactivity similar to used conventional cigarette filters. Oxidants/reactive oxygen species reactivity in e-cigarette aerosols was also similar to oxidant reactivity in cigarette smoke. A cascade particle impactor allowed sieving of a range of particle size distributions between 0.450 and 2.02 µm in aerosols from an e-cigarette. Copper, being among these particles, is 6.1 times higher per puff than reported previously for conventional cigarette smoke. The detection of a potentially cytotoxic metal as well as oxidants from e-cigarette and its components raises concern regarding the safety of e-cigarettes use and the disposal of e-cigarette waste products into the environment.

Increased levels of airway neutrophils reduce the inhibitory effects of inhaled glucocorticosteroids on allergen-induced airway eosinophils.

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 glucocorticosteroids significantly attenuated the early and late asthmatic responses, and the number of allergen-induced sputum eosinophils (P<0.05). There was a significant negative relationship between the number of sputum neutrophils at baseline, and the per cent inhibition of allergen-induced sputum eosinophils measured at 7 h (r=-0.61, P<0.001) and 24 h (r=-0.73, P<0.0001) after challenge, suggesting that glucocorticosteroids are less effective in attenuating allergen-induced airway inflammation in subjects with high levels of neutrophils. There was no correlation between the number of sputum eosinophils at baseline and the per cent inhibition of allergen-induced responses. CONCLUSIONS: Baseline airway neutrophils, not eosinophils, can be used to predict the efficacy of inhaled steroids on allergen-induced sputum eosinophils.

Distance dependence of the charge transfer rate for peptide nucleic acid monolayers.

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.

Metal binding to bipyridine-modified PNA.

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.

Influence of metal coordination on the mismatch tolerance of ligand-modified PNA duplexes.

Recent studies on metal incorporation in ligand-modified nucleic acids have focused on the effect of metal coordination on the stability of metal-containing duplexes or triplexes and on the metal binding selectivity but did not address the effect of the sequence of the nucleic acid in which the ligands are incorporated. We have introduced 8-hydroxyquinoline Q in 10-mer PNA strands with various sequences and have investigated the properties of the duplexes formed from these strands upon binding of Cu(2+). Variable-temperature UV-vis spectroscopy shows that, in the presence of Cu(2+), duplexes are formed even from ligand-modified Q-PNA strands that have a large number of mismatches. Spectrophotometric titrations demonstrate that at any temperature, one Cu(2+) ion binds a pair of Q-PNA strands that each contain one 8-hydroxyquinoline, but below the melting temperature, the PNA duplex exerts a supramolecular chelate effect, which prevents the transformation in the presence of excess Cu(2+) of the 1:2 Cu(2+):Q-PNA complexes into 1:1 complexes. EPR spectroscopy gives further support for the existence in the duplexes of [CuQ(2)] moieties that are similar to the corresponding square planar synthetic complex formed between Cu(2+) and 8-hydroxyquinoline. As PNA duplexes show a preferred handedness due to the chiral induction effect of a C-terminal l-lysine, which is transmitted through stacking interactions within the duplex, only if the metal-containing duplex has complementary strands, does it show a chiral excess measured by CD spectroscopy. The strong effect of the metal-ligand moiety is suggestive of an increased correlation length in PNA duplexes that contain such moieties. These results indicate that strong metal-ligand alternative base pairs significantly diminish the importance of Watson-Crick base pairing for the formation of a stable PNA duplex and lead to high mismatch tolerance, a principle that can be used in the construction of hybrid inorganic-nucleic acid nanostructures.

Different profiles of T-cell IFN-gamma and IL-12 in allergen-induced early and dual responders with asthma.

BACKGROUND: IFN-gamma and IL-12 are anti-inflammatory cytokines released from various cells, including T cells. Allergen inhalation by atopic subjects with asthma results in 2 bronchoconstrictor phenotypes, termed isolated early and dual responders . Persistence of allergen-induced airway response and inflammation is a distinctive feature of dual responders. OBJECTIVE: To evaluate the roles of IFN-gamma and IL-12 in resolving allergen-induced airway inflammation by comparing T lymphocytes (CD4 + and CD8 + cells) producing these cytokines in isolated early and dual responders. METHODS: Twenty-four subjects with asthma (12 isolated early and 12 dual responders) were challenged with inhaled allergen. Peripheral blood and induced sputum were taken before and 1 day, 3 days, and 7 days after challenge. Frequency of IFN-gamma, IL-12, IL-4, and IL-13 producing CD4 + and CD8 + cells was assessed by using flow cytometry. RESULTS: After allergen, both CD4 + and CD8 + IFN-gamma positive cells in peripheral blood significantly decreased in dual responders only, whereas CD4 + and CD8 + IFN-gamma positive cells in induced sputum significantly increased in isolated early responders only. By contrast, IL-12 positive cells in peripheral blood significantly increased after allergen challenge only in isolated early responders. The ratio of CD4 + and CD8 + IL-4/IFN-gamma positive cells in peripheral blood significantly decreased in isolated early responders by 3 days and had recovered by 7 days. CONCLUSION: These results suggest that contrasting profiles of IFN-gamma and IL-12 production may be responsible for different time courses of allergen-induced airway responses between isolated early and dual responders.

Protection by budesonide and fluticasone on allergen-induced airway responses after discontinuation of therapy.

BACKGROUND: Treatment with inhaled steroids is an effective method of reducing bronchoconstriction and airway inflammation after allergen challenge. However, the duration of 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 microg of budesonide twice daily, 200 microg 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.