Targeting In Vivo Metabolic Vulnerabilities of Th2 and Th17 Cells Reduces Airway Inflammation.

T effector cells promote inflammation in asthmatic patients, and both Th2 and Th17 CD4 T cells have been implicated in severe forms of the disease. The metabolic phenotypes and dependencies of these cells, however, remain poorly understood in the regulation of airway inflammation. In this study, we show the bronchoalveolar lavage fluid of asthmatic patients had markers of elevated glucose and glutamine metabolism. Further, peripheral blood T cells of asthmatics had broadly elevated expression of metabolic proteins when analyzed by mass cytometry compared with healthy controls. Therefore, we hypothesized that glucose and glutamine metabolism promote allergic airway inflammation. We tested this hypothesis in two murine models of airway inflammation. T cells from lungs of mice sensitized with Alternaria alternata extract displayed genetic signatures for elevated oxidative and glucose metabolism by single-cell RNA sequencing. This result was most pronounced when protein levels were measured in IL-17-producing cells and was recapitulated when airway inflammation was induced with house dust mite plus LPS, a model that led to abundant IL-4- and IL-17-producing T cells. Importantly, inhibitors of the glucose transporter 1 or glutaminase in vivo attenuated house dust mite + LPS eosinophilia, T cell cytokine production, and airway hyperresponsiveness as well as augmented the immunosuppressive properties of dexamethasone. These data show that T cells induce markers to support metabolism in vivo in airway inflammation and that this correlates with inflammatory cytokine production. Targeting metabolic pathways may provide a new direction to protect from disease and enhance the effectiveness of steroid therapy.

Hyaluronan and Its Heavy Chain Modification in Asthma Severity and Experimental Asthma Exacerbation.

Hyaluronan (HA) is a large (>1500 kDa) polysaccharide of the extracellular matrix that has been linked to severity and inflammation in asthma. During inflammation, HA becomes covalently modified with heavy chains (HC-HA) from inter-α-inhibitor (IαI), which functions to increase its avidity for leukocytes. Our murine model of allergic pulmonary inflammation suggested that HC-HA may contribute to inflammation, adversely effecting lower airway remodeling and asthma severity. Our objective was to characterize the levels of HA and HC-HA in asthmatic subjects and to correlate these levels with asthma severity. We determined the levels and distribution of HA and HC-HA (i) from asthmatic and control lung tissue, (ii) in bronchoalveolar lavage fluid obtained from non-severe and severe asthmatics and controls, and (iii) in serum and urine from atopic asthmatics after an experimental asthma exacerbation. HC-HA distribution was observed (i) in the thickened basement membrane of asthmatic lower airways, (ii) around smooth muscle cells of the asthmatic submucosa, and (iii) around reserve cells of the asthmatic epithelium. Patients with severe asthma had increased HA levels in bronchoalveolar lavage fluid that correlated with pulmonary function and nitric oxide levels, whereas HC-HA was only observed in a patient with non-severe asthma. After an experimental asthma exacerbation, serum HA was increased within 4 h after challenge and remained elevated through 5 days after challenge. Urine HA and HC-HA were not significantly different. These data implicate HA and HC-HA in the pathogenesis of asthma severity that may occur in part due to repetitive asthma exacerbations over the course of the disease.

Medication Desensitization: Characterization of Outcomes and Risk Factors for Reactions.

BACKGROUND: Although its mechanisms are poorly understood, desensitization has been used to induce a temporary state of immune unresponsiveness in patients who have IgE-, non-IgE-, or pharmacologically mediated reactions when a drug has no alternatives. OBJECTIVES: The purpose of this study was to characterize the outcomes and identify risk factors for reactions during drug desensitization. METHODS: A retrospective review of electronic medical records of adult patients undergoing drug desensitization from January 1, 2011, to December 31, 2013, was conducted in 2 intensive care units at a tertiary medical center. We used multivariate analysis to determine if specified risk factors were associated with reacting during the desensitization. Reactions were classified according to the pretest probability prior to desensitization, and then, reactions during desensitization were classified based on the occurrence of cutaneous reactions as follows: successful with no reaction, mild reaction, moderate reaction, or failed. Failure could result from any systemic allergic or cutaneous reaction resulting in procedure termination. The desensitizations were also assessed to determine if the patient required de-escalation secondary to a reaction. RESULTS: A total of 88 desensitizations were performed in 69 patients. Desensitization was completed with no cutaneous reaction in 85% of patients. No baseline characteristic, medication class (P = 0.46), or indication for desensitization (P = 0.59) was associated with having a reaction. Reported histories of urticaria (P < 0.0001) and labored breathing (P = 0.003) during prior exposure were significant in identifying patients who might have a reaction during desensitization. However, neither history of urticaria nor labored breathing was independently associated with having a reaction in multivariate analysis (OR = 0.979, 95% CI = 0.325-2.952, P = 0.970, and OR = 1.626, 95% CI = 0.536-4.931, P = 0.739, respectively). CONCLUSIONS: Drug desensitization is safe for patients who have no alternative for therapy. Reported allergy histories of urticaria and labored breathing are both associated with having a reaction during the desensitization process.

Blockade of the programmed death-1 pathway restores sarcoidosis CD4(+) T-cell proliferative capacity.

RATIONALE: Effective therapeutic interventions for chronic, idiopathic lung diseases remain elusive. Normalized T-cell function is an important contributor to spontaneous resolution of pulmonary sarcoidosis. Up-regulation of inhibitor receptors, such as programmed death-1 (PD-1) and its ligand, PD-L1, are important inhibitors of T-cell function. OBJECTIVES: To determine the effects of PD-1 pathway blockade on sarcoidosis CD4(+) T-cell proliferative capacity. METHODS: Gene expression profiles of sarcoidosis and healthy control peripheral blood mononuclear cells were analyzed at baseline and follow-up. Flow cytometry was used to measure ex vivo expression of PD-1 and PD-L1 on systemic and bronchoalveolar lavage-derived cells of subjects with sarcoidosis and control subjects, as well as the effects of PD-1 pathway blockade on cellular proliferation after T-cell receptor stimulation. Immunohistochemistry analysis for PD-1/PD-L1 expression was conducted on sarcoidosis, malignant, and healthy control lung specimens. MEASUREMENTS AND MAIN RESULTS: Microarray analysis demonstrates longitudinal increase in PDCD1 gene expression in sarcoidosis peripheral blood mononuclear cells. Immunohistochemistry analysis revealed increased PD-L1 expression within sarcoidosis granulomas and lung malignancy, but this was absent in healthy lungs. Increased numbers of sarcoidosis PD-1(+) CD4(+) T cells are present systemically, compared with healthy control subjects (P < 0.0001). Lymphocytes with reduced proliferative capacity exhibited increased proliferation with PD-1 pathway blockade. Longitudinal analysis of subjects with sarcoidosis revealed reduced PD-1(+) CD4(+) T cells with spontaneous clinical resolution but not with disease progression. CONCLUSIONS: Analogous to the effects in other chronic lung diseases, these findings demonstrate that the PD-1 pathway is an important contributor to sarcoidosis CD4(+) T-cell proliferative capacity and clinical outcome. Blockade of the PD-1 pathway may be a viable therapeutic target to optimize clinical outcomes.

Asthmatic airway neutrophilia after allergen challenge is associated with the glutathione S-transferase M1 genotype.

RATIONALE: Asthma is a heterogeneous lung disorder characterized by airway inflammation and airway dysfunction, manifesting as hyperresponsiveness and obstruction. Glutathione S-transferase M1 (GSTM1) is a multifunctional phase II enzyme and regulator of stress-activated cellular signaling relevant to asthma pathobiology. A common homozygous deletion polymorphism of the GSTM1 gene eliminates enzyme activity. OBJECTIVES: To determine the effect of GSTM1 on airway inflammation and reactivity in adults with established atopic asthma in vivo. METHODS: Nineteen GSTM1 wild-type and eighteen GSTM1-null individuals with mild atopic asthma underwent methacholine and inhaled allergen challenges, and endobronchial allergen provocations through a bronchoscope. MEASUREMENTS AND MAIN RESULTS: The influx of inflammatory cells, panels of cytokines and chemokines linked to asthmatic inflammation, F(2)-isoprostanes (markers of oxidative stress), and IgE were measured in bronchoalveolar lavage fluid at baseline and 24 hours after allergen instillation. Individuals with asthma with the GSTM1 wild-type genotype had greater baseline and allergen-provoked airway neutrophilia and concentrations of myeloperoxidase than GSTM1-null patients. In contrast, the eosinophilic inflammation was unaffected by GSTM1. The allergen-stimulated generation of acute-stress and proneutrophilic mediators, tumor necrosis factor-α, CXCL-8, IL-1ß, and IL-6, was also greater in the GSTM1 wild-type patients. Moreover, post-allergen airway concentrations of IgE and neutrophil-generated mediators, matrix metalloproteinase-9, B-cell activating factor, transforming growth factor-ß1, and elastase were higher in GSTM1 wild-type individuals with asthma. Total airway IgE correlated with B-cell activating factor concentrations. In contrast, levels of F(2)-isoprostane were comparable in both groups. Finally, GSTM1 wild-type individuals with asthma required lower threshold concentrations of allergen to produce bronchoconstriction. CONCLUSIONS: The functional GSTM1 genotype promotes neutrophilic airway inflammation in humans with atopic asthma in vivo.

Exhaled breath condensate formate after inhaled allergen provocation in atopic asthmatics in vivo.

OBJECTIVE: The dual actions of S-nitrosoglutathione reductase comprise reduction of S-nitrosoglutathione, a potent endogenous airway smooth muscle relaxant that is depleted in asthmatics, and detoxification of formaldehyde to formate. Airway formate production is increased in children with asthma, suggesting increased activity of S-nitrosoglutathione reductase. We determined formate in exhaled breath condensate from adult atopic asthmatics with asthma exacerbation produced by inhaled allergen in vivo, METHODS: Twenty-two adult atopic asthmatics underwent inhaled allergen challenge using specific allergen. Exhaled breath condensate was collected at baseline, 1 h after inhalation of the provocative dose of allergen, and then every 2 h for 8 h during the challenge. Formate was analyzed by ion chromatography, RESULTS: Eleven asthmatics developed an isolated early airway response, and another 11 volunteers early response followed by late airway response (dual response). Formate concentrations doubled 1 h post-challenge in asthmatics with dual-airway response but essentially unchanged in patients with an isolated early reaction, CONCLUSIONS: Dual-airway response to allergen in atopic asthmatics could be associated with increased activity of S-nitrosoglutathione reductase as suggested by greater concentrations of formate in exhaled breath condensate. Measurement of formate in exhaled breath condensate could serve as a noninvasive biomarker of S-nitrosoglutathione reductase activity in vivo. Our results need to be confirmed in a larger group of asthmatics.

Low levels of tissue factor lead to alveolar haemorrhage, potentiating murine acute lung injury and oxidative stress.

BACKGROUND: Systemic blockade of tissue factor (TF) attenuates acute lung injury (ALI) in animal models of sepsis but the effects of global TF deficiency are unknown. We used mice with complete knockout of mouse TF and low levels (∼1%) of human TF (LTF mice) to test the hypothesis that global TF deficiency attenuates lung inflammation in direct lung injury. METHODS: LTF mice were treated with 10 µg of lipopolysaccharide (LPS) or vehicle administered by direct intratracheal injection and studied at 24 h. RESULTS: Contrary to our hypothesis, LTF mice had increased lung inflammation and injury as measured by bronchoalveolar lavage cell count (3.4×10(5) wild-type (WT) LPS vs 3.3×10(5) LTF LPS, p=0.947) and protein (493 µg/ml WT LPS vs 1014 µg/ml LTF LPS, p=0.006), proinflammatory cytokines (TNF-α, IL-10, IL-12, p<0.035 WT LPS vs LTF LPS) and histology compared with WT mice. LTF mice also had increased haemorrhage and free haemoglobin in the airspace accompanied by increased oxidant stress as measured by lipid peroxidation products (F(2) isoprostanes and isofurans). CONCLUSIONS: These findings indicate that global TF deficiency does not confer protection in a direct lung injury model. Rather, TF deficiency causes increased intra-alveolar haemorrhage following LPS leading to increased lipid peroxidation. Strategies to globally inhibit TF may be deleterious in patients with ALI.

Natural-source d-α-tocopheryl acetate inhibits oxidant stress and modulates atopic asthma in humans in vivo.

BACKGROUND: Asthma is associated with oxidant stress and diminished antioxidant defenses. Yet, the mechanistic role of oxidant stress and antioxidant supplementation in human asthmatics remains uncertain. We determined the effect of high doses of the antioxidant natural-source d-α-tocopheryl acetate for 16 weeks on allergen-induced airway oxidant stress, inflammation, and bronchial responsiveness to methacholine and allergen in atopic asthmatics in vivo. METHODS: Thirty-three mild atopic asthmatics underwent bronchoscopy with baseline bronchoalveolar lavage and segmental allergen challenge. The allergen-challenged airway was lavaged 24 h later. At least 3 weeks later, patients underwent inhaled challenges with methacholine and specific allergen. Volunteers took 1500 IU of natural-source d-α-tocopheryl acetate daily for at least 16 weeks. At the end of the treatment, the two bronchoscopies and inhaled methacholine and allergen challenges were repeated. F(2)-isoprostanes, specific markers of oxidant stress, and selected Th1 and Th2 cytokines were analyzed in the lavage fluid. RESULTS: Following supplementation of natural-source d-α-tocopheryl acetate, plasma concentrations of α-tocopherol increased and γ-tocopherol decreased. Both baseline and allergen-induced F(2)-isoprostanes significantly decreased, providing biochemical evidence for an antioxidant effect. Natural-source d-α-tocopheryl acetate reduced allergen-provoked concentrations of interleukin 3 and interleukin 4 and augmented levels of interleukin 12 in bronchoalveolar lavage fluid. Natural-source d-α-tocopheryl acetate improved airway responsiveness to methacholine but did not alter airway reactivity to specific allergen. CONCLUSIONS: Inhibition of oxidant stress by natural-source d-α-tocopheryl acetate modulates allergic inflammation and airway hyperresponsiveness in human atopic asthmatics in vivo. These results need to be confirmed by a randomized placebo-controlled trial.

Iloprost inhalation in mild asthma.

OBJECTIVE: To determine the feasibility of administering iloprost by inhalation in patients with mild atopic asthma. METHODS: Volunteers underwent supervised inhalation of iloprost in the clinic with measurement of spirometry and blood pressure for 2 hours. The volunteers then inhaled iloprost four times daily at a dose of 2.5 or 5 µg for 14 days. Spirometry, asthma questionnaires, peak flow diaries, measurement of methacholine responsiveness, and exhaled nitric oxide concentrations were obtained prior to and after the treatment period. RESULTS: Chronic inhalation of iloprost (2.5-5 µg) did not alter spirometry or methacholine responsiveness. CONCLUSION: Inhaled iloprost in carefully selected volunteers with mild asthma appears to be a suitable intervention to explore the effects of prostacyclin in human asthma.

Eosinophil and neutrophil extracellular DNA traps in human allergic asthmatic airways.

BACKGROUND: Asthma is a heterogeneous inflammatory airway disorder that involves eosinophilic and noneosinophilic phenotypes. Unlike in healthy lungs, eosinophils are often present in atopic asthmatic airways, although a subpopulation of asthmatic subjects predominantly experience neutrophilic inflammation. Recently, it has been demonstrated that eosinophils and neutrophils generate bactericidal extracellular traps consisting of DNA and cytotoxic granule proteins. OBJECTIVE: We sought to explore whether living eosinophils and neutrophils infiltrating human atopic asthmatic airways actively form extracellular DNA traps in vivo. METHODS: Quantitative analysis of eosinophils releasing DNA was performed in endobronchial biopsy specimens from 20 human subjects with mild atopic asthma at baseline and after local allergen challenge and 10 healthy subjects. DNA was stained with propidium iodine and major basic protein with specific antibody. Differential cell counts and cytokines/chemokines were assessed in bronchoalveolar lavage fluid. RESULTS: Asthmatic airways were infiltrated with a significantly higher number of eosinophils than healthy airways (39.3 ± 4.6 vs 0.4 ± 0.9, P < .0001). All asthmatic subjects but only 1 control subject expressed eosinophils releasing DNA that colocalized with major basic protein (33.65 ± 20.33 vs 0.3 ± 0.9 per high-power field, P < .0001). Four asthmatic subjects mostly expressed neutrophilic inflammation and neutrophil DNA traps. Allergen challenge had no significant quantitative effect on eosinophil or neutrophil DNA traps. Airway eosinophils or DNA traps did not correlate with either bronchoalveolar lavage levels of IL-5, IFN-γ, or eotaxin or the provoking doses of methacholine or allergen in asthmatic subjects. CONCLUSIONS: Extracellular DNA traps are generated by eosinophils and neutrophils in human atopic asthmatic airways in vivo. The mechanism and role of this new finding will necessitate further investigation.

Mitochondrial CaMKII inhibition in airway epithelium protects against allergic asthma.

Excessive ROS promote allergic asthma, a condition characterized by airway inflammation, eosinophilic inflammation, and increased airway hyperreactivity (AHR). The mechanisms by which airway ROS are increased and the relationship between increased airway ROS and disease phenotypes are incompletely defined. Mitochondria are an important source of cellular ROS production, and our group discovered that Ca2+/calmodulin-dependent protein kinase II (CaMKII) is present in mitochondria and activated by oxidation. Furthermore, mitochondrial-targeted antioxidant therapy reduced the severity of allergic asthma in a mouse model. Based on these findings, we developed a mouse model of CaMKII inhibition targeted to mitochondria in airway epithelium. We challenged these mice with OVA or Aspergillus fumigatus. Mitochondrial CaMKII inhibition abrogated AHR, inflammation, and eosinophilia following OVA and A. fumigatus challenge. Mitochondrial ROS were decreased after agonist stimulation in the presence of mitochondrial CaMKII inhibition. This correlated with blunted induction of NF-κB, the NLRP3 inflammasome, and eosinophilia in transgenic mice. These findings demonstrate a pivotal role for mitochondrial CaMKII in airway epithelium in mitochondrial ROS generation, eosinophilic inflammation, and AHR, providing insights into how mitochondrial ROS mediate features of allergic asthma.

Oxidant stress modulates murine allergic airway responses.

The allergic inflammation occurring in asthma is believed to be accompanied by the production of free radicals. To investigate the role of free radicals and the cells affected we turned to a murine model of allergic inflammation produced by sensitization to ovalbumin with subsequent aerosol challenge. We examined oxidant stress by measuring and localizing the sensitive and specific marker of lipid peroxidation, the F2-isoprostanes. F2-isoprostanes in whole lung increased from 0.30 +/- 0.08 ng/lung at baseline to a peak of 0.061 +/- 0.09 ng/lung on the ninth day of daily aerosol allergen challenge. Increased immunoreactivity to 15-F2t-IsoP (8-iso-PGF2alpha) or to isoketal protein adducts was found in epithelial cells 24 h after the first aerosol challenge and at 5 days in macrophages. Collagen surrounding airways and blood vessels, and airway and vascular smooth muscle, also exhibited increased immunoreactivity after ovalbumin challenge. Dietary vitamin E restriction in conjunction with allergic inflammation led to increased whole lung F2-isoprostanes while supplemental vitamin E suppressed their formation. Similar changes in immunoreactivity to F2-isoprostanes were seen. Airway responsiveness to methacholine was also increased by vitamin E depletion and decreased slightly by supplementation with the antioxidant. Our findings indicate that allergic airway inflammation in mice is associated with an increase in oxidant stress, which is most striking in airway epithelial cells and macrophages. Oxidant stress plays a role in the production of airway responsiveness.

Altered prostanoid production by fibroblasts cultured from the lungs of human subjects with idiopathic pulmonary fibrosis.

BACKGROUND: Prostanoids are known to participate in the process of fibrogenesis. Because lung fibroblasts produce prostanoids and are believed to play a central role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), we hypothesized that fibroblasts (HF) cultured from the lungs of patients with IPF (HF-IPF) have an altered balance between profibrotic (thromboxane [TX]A2) and antifibrotic (prostacyclin [PGI2]) prostaglandins (PGs) when compared with normal human lung fibroblasts (HF-NL). METHODS: We measured inducible cyclooxygenase (COX)-2 gene and protein expression, and a profile of prostanoids at baseline and after IL-1beta stimulation. RESULTS: In both HF-IPF and HF-NL COX-2 expression was undetectable at baseline, but was significantly upregulated by IL-1beta. PGE2 was the predominant COX product in IL-1beta-stimulated cells with no significant difference between HF-IPF and HF-NL (28.35 [9.09-89.09] vs. 17.12 [8.58-29.33] ng/10(6) cells/30 min, respectively; P = 0.25). TXB2 (the stable metabolite of TXA2) production was significantly higher in IL-1beta-stimulated HF-IPF compared to HF-NL (1.92 [1.27-2.57] vs. 0.61 [0.21-1.64] ng/10(6) cells/30 min, respectively; P = 0.007) and the ratio of PGI2 (as measured by its stable metabolite 6-keto-PGF1alpha) to TXB2 was significantly lower at baseline in HF-IPF (0.08 [0.04-0.52] vs. 0.12 [0.11-0.89] in HF-NL; P = 0.028) and with IL-1beta stimulation (0.24 [0.05-1.53] vs. 1.08 [0.51-3.79] in HF-NL; P = 0.09). CONCLUSION: An alteration in the balance of profibrotic and antifibrotic PGs in HF-IPF may play a role in the pathogeneses of IPF.

The prostaglandin E agonist, misoprostol, inhibits airway IL-5 production in atopic asthmatics.

BACKGROUND: Prostaglandin E2 is a potent immunomodulator that inhibits the early and late bronchoconstriction to inhaled allergen, as well as inhibiting the acute allergen-induced release of mediators into the human airway. To determine if the stable prostaglandin E agonist misoprostol could alter the late allergic formation of mediators we measured the appearance of eosinophils and key cytokines in the bronchoalveolar lavage fluid 24 h after allergen instillation. METHODS: Six atopic asthmatics underwent bronchoscopy, alveolar lavage and antigen instillation followed 24 h later by bronchoalveolar lavage. Eosinophil counts were done, together with measurements of IL-4, IL-5, eotaxin, RANTES and cysteinyl leukotrienes by immunoassay. The study was done in randomized blinded fashion while the volunteers took placebo or 600 microg of misoprostol four times a day (QID). RESULTS: Misoprostol significantly decreased the appearance of IL-5 late after allergen challenge. Eotaxin levels were reduced, but not statistically significantly. Eosinophil number, RANTES, eosinophil cationic protein and cysteinyl leukotrienes were not altered by misoprostol. CONCLUSIONS: Misoprostol reduces the formation of IL-5 late after allergen challenge, perhaps by inhibiting eosinophil, mast cell, and/or T lymphocyte production of IL-5. Despite decreases in IL-5 and eotaxin, eosinophils were recruited and activated by allergen.

CaMKII is essential for the proasthmatic effects of oxidation.

Increased reactive oxygen species (ROS) contribute to asthma, but little is known about the molecular mechanisms connecting increased ROS with characteristic features of asthma. We show that enhanced oxidative activation of the Ca(2+)/calmodulin-dependent protein kinase (ox-CaMKII) in bronchial epithelium positively correlates with asthma severity and that epithelial ox-CaMKII increases in response to inhaled allergens in patients. We used mouse models of allergic airway disease induced by ovalbumin (OVA) or Aspergillus fumigatus (Asp) and found that bronchial epithelial ox-CaMKII was required to increase a ROS- and picrotoxin-sensitive Cl(-) current (ICl) and MUC5AC expression, upstream events in asthma progression. Allergen challenge increased epithelial ROS by activating NADPH oxidases. Mice lacking functional NADPH oxidases due to knockout of p47 and mice with epithelial-targeted transgenic expression of a CaMKII inhibitory peptide or wild-type mice treated with inhaled KN-93, an experimental small-molecule CaMKII antagonist, were protected against increases in ICl, MUC5AC expression, and airway hyperreactivity to inhaled methacholine. Our findings support the view that CaMKII is a ROS-responsive, pluripotent proasthmatic signal and provide proof-of-concept evidence that CaMKII is a therapeutic target in asthma.

Vitamin E prevents NRF2 suppression by allergens in asthmatic alveolar macrophages in vivo.

Asthma is a chronic inflammatory airway disease associated with increased generation of reactive oxidant species and disturbed antioxidant defenses. NRF2 is the master transcription factor that regulates the expression of Phase II antioxidant and detoxifying enzymes. Disruption of NRF2 augments oxidative stress and inflammation in a mouse model of asthma, suggesting a protective role for NRF2 in the lungs in vivo. Yet, little is known about the regulation and function of NRF2 in human asthmatics. Using segmental allergen challenge, a well-established experimental model of IgE-mediated asthma exacerbation in human atopic asthmatics, we investigated the effects of a specific allergen and the modulatory role of vitamin E on NRF2 and a NRF2-target gene, superoxide dismutase, in alveolar macrophages recovered from the airways at 24h after allergen instillation in vivo. Allergen-provoked airway inflammation in sensitive asthmatics caused a profound inhibition of macrophage NRF2 activity and superoxide dismutase, rendering them incapable of responding to the NRF2 inducers. Prolonged treatment with high doses of the antioxidant vitamin E lessened this allergen-induced drop in alveolar macrophage NRF2. These results are the first to demonstrate that NRF2 expression in human asthmatics is compromised upon allergen challenge but can be rescued by vitamin E in vivo.

Effect of allergen challenge on the percentage of natural killer T cells in patients with atopic asthma.

BACKGROUND: Invariant natural killer T (iNKT) cells produce cytokines that can influence the immune response to infection or allergen. Controversy surrounds their role in exacerbations of human atopic asthma. OBJECTIVES: To determine the effect of allergen challenge on iNKT cells' mobilization to the airways and blood and to establish the relationship between airway iNKT cells and bronchial sensitivity to methacholine and allergen in patients with atopic asthma. METHODS: We performed flow cytometry analysis for the iNKT cell receptor Va24 and V311 on bronchoalveolar lavage (BAL) cells at baseline and 24 hours after segmental antigen challenge (SAC) (n = 8) and on peripheral blood mononuclear cells (PBMCs) at baseline and 6 to 7 hours after inhaled allergen (n = 10). Challenges were performed using standardized protein allergens to which the participants were sensitive. RESULTS: The number of BAL eosinophils increased 24 hours after SAC. The low mean (SEM) baseline percentage of iNKT cells in the population of BAL CD4' T cells remained unchanged 24 hours after SAC (0.035% [0.01%] vs 0.049% [0.02%]; n = 8; P = .50). Likewise, the mean (SEM) percentage of iNKT cells in PBMCs was unchanged after inhaled allergen provocation (0.068% [0.033%] vs 0.057% [0.026%]; n = 10; P = .10). No correlation was found between iNKT cells in BAL and the sensitivity to inhaled methacholine or allergen. CONCLUSIONS: The percentages of both BAL and peripheral blood iNKT cells did not increase during allergen provoked asthmatic responses. Determination of iNKT cells in airway biopsy specimens would allow conclusively ruling against mobilization of iNKT cells in allergen-induced asthma exacerbation in humans.

Use of olopatadine ophthalmic solution and reactivity of histamine skin testing.

The significant morbidity of allergic rhinitis and allergic conjunctivitis necessitates that diagnosis must be as accurate as possible. However, the very drugs used to treat allergic symptoms have been found to suppress histamine-induced skin testing, making the diagnosis very challenging. Oral formulations of antihistamines are well known to diminish skin test reactivity, but ocular application has never been studied to our knowledge. This study was performed to evaluate whether olopatadine hydrochloride 0.2% ophthalmic solution suppressed histamine-induced wheals and flares on skin-prick testing. A randomized, double-blinded, placebo-controlled, single-center, cross-over pilot study was performed that compared histamine-induced wheal and flare areas after 7-10 days of treatment with both olopatadine 0.2% ophthalmic solution and artificial tears, allowing for a 7- to 10-day washout period between medications. From a total of 24 patients randomized, 21 subjects completed the study, 86% of whom were female. There were no statistically significant differences among both the wheal and the flare areas when comparing treatment with olopatadine and placebo, under the 5% significance level. Although characterized by a small sample size and a preponderance of female subjects, our data suggest that olopatadine does not suppress wheal and flare areas during allergy testing, and discontinuation in preparation for skin-prick testing does not appear to be necessary.