Nasal hyperreactivity in allergic rhinitis and chronic rhinosinusitis with polyps: a role for neuronal pathways.

BACKGROUND: Nasal hyperreactivity (NHR) is prevalent in all chronic upper airway inflammatory phenotypes, including allergic rhinitis (AR) and chronic rhinosinusitis with nasal polyps (CRSwNP). Although NHR in patients with non-allergic rhinitis is mediated by neuronal pathways, AR and CRSwNP are mainly characterized by type 2 inflammation. METHODS: Eighteen healthy controls and 45 patients with symptomatic AR/CRSwNP underwent a cold, dry air (CDA) provocation test for objective diagnosis of NHR. Before and after, questionnaires were filled out and nasal secretions and biopsies were collected. Markers for neurogenic inflammation (substance P, calcitonin gene-related peptide, neurokinin A), epithelial activation (IL-33), and histamine were measured in secretions by ELISA; and expression of neuronal markers PGP9.5, TRPV1, and TRPM8 was studied in biopsies by RT-q-PCR. Effects of histamine on TRPV1/A1 were studied with Ca2+-imaging using murine trigeminal neurons. RESULTS: CDA-provocation reduced peak nasal inspiratory flow (PNIF) of patients with subjective NHR but not of non-NHR controls/patients CDA-provocation reduced peak nasal inspiratory flow (PNIF) of patients with subjective NHR but not of non-NHR controls/patients. Subjective (subjectively reported effect of CDA) and objective (decrease in PNIF) effects of CDA were significantly correlated. Levels of neuropeptides and histamine in nasal secretions and mRNA expression of PGP9.5, TRPV1, and TRPM8 correlated with CDA-induced PNIF-reduction. CDA-provocation induced an increase in IL-33-levels. Both TRPV1 and TRPA1 expressed on afferent neurons were sensitized by exposure to histamine. CONCLUSION: NHR is not an on/off phenomenon but spans a continuous spectrum of reactivity. A neurogenic inflammatory background and increased histamine-levels are risk factors for NHR in AR/CRSwNP.

Nasal symptoms, epithelial injury and neurogenic inflammation in elite swimmers.

BACKGROUND: A high burden of lower airway symptoms is found in elite swimmers. To what extent elite swimmers suffer from upper airway symptoms and how these associate with nasal inflammation is less clear. We here aimed to evaluate upper airway symptoms and nasal inflammation in elite athletes. METHODOLOGY: Elite swimmers, indoor athletes and age-matched controls were recruited. Upper airway symptoms were assessed by sino-nasal outcome test (SNOT)-22 questionnaire. Visual Analogue score (VAS) for nasal symptoms as well as neurogenic and inflammatory mediators in nasal fluid were assessed at baseline, immediately and 24-hours after sport-specific training. The effect of hypochlorite on nasal epithelial cells was evaluated in vitro. RESULTS: Baseline SNOT-22 and VAS for nasal itch and impaired smell were significantly higher in swimmers compared to controls. Nasal substance P and uric acid levels were increased in elite swimmers 24-hours after swimming compared to baseline. In elite swimmers, uric acid levels 24-hours post-exercise correlated with baseline SNOT-22. As increased symptoms and inflammation were found in swimmers but not in indoor athletes, we hypothesized that hypochlorite exposure might be the underlying mechanism. In vitro, the highest dose of hypochlorite decreased nasal epithelial cell integrity and induced release of uric acid. CONCLUSION: Upper airway symptoms are frequently reported in elite swimmers. Intensive swimming resulted in a delayed increase of epithelial injury and neurogenic inflammation.

Feasibility to apply eucapnic voluntary hyperventilation in young elite athletes.

INTRODUCTION: Exercise-induced bronchoconstriction (EIB) is more common in athletes compared to the general population. The eucapnic voluntary hyperventilation test is used to detect EIB in adult athletes. It is however unclear whether this technique is also applicable to young athletes. METHODS: Young athletes (basketball (n = 13), football (n = 19), swimming (n = 12)) were recruited at the start of their elite sports career (12-14 years). Eight age-matched controls were also recruited. Eucapnic voluntary hyperventilation test was performed according to ATS guidelines in all subjects. A second (after 1 year, n = 32) and third (after 2 years, n = 39) measurement was performed in a subgroup of athletes and controls. RESULTS: At time of first evaluation, 3/13 basketball players, 4/19 football players, 5/11 swimmers and 1/8 controls met criteria for EIB (fall in FEV1≥10% after EVH). A ventilation rate of >85% of the maximal voluntary ventilation (MVV) is recommended by current guidelines (for adults) but was only achieved by a low number of individuals (first occasion: 27%, third occasion: 45%) However, MVV in young athletes corresponds to 30 times FEV1, which is equivalent to 85% of MVV in adults. A threshold of 70% of MVV (21 times FEV1) is feasible in the majority of young athletes. CONCLUSION: EIB is present in a substantial number of individuals at the age of 12-14 years, especially in swimmers. This underscores the importance of screening for EIB at this age. EVH is feasible in young elite athletes, however target ventilation needs to be adjusted accordingly.

Damage-associated molecular pattern and innate cytokine release in the airways of competitive swimmers.

BACKGROUND: Daily intensive exercise by elite athletes can result in exercise-induced asthma especially in elite swimmers and this may be linked to epithelial damage. OBJECTIVE: To study airway epithelial damage and release of damage-associated molecular patterns (DAMPs) after intensive exercise in elite athletes and controls. METHODS: We recruited competitive swimmers (n = 26), competitive indoor athletes (n = 13) and controls (n = 15) without any history of asthma. Lung function was measured before, immediately after and 24 h after a 90-min intensive exercise protocol. Sputum induction was performed at baseline and 24 h after exercise. Exercise-induced bronchoconstriction (EIB) was assessed by the eucapnic voluntary hyperventilation test. RESULTS: Baseline sputum uric acid, high mobility group box-1, CXCL8 mRNA, sputum neutrophils and serum Clara cell protein-16 (CC-16) were significantly higher in competitive swimmers compared with controls. Intensive swimming for 90 min resulted in an increase of sputum IL-1ß, IL-6 and TNF mRNA in competitive swimmers, and of sputum IL-6 mRNA and sputum neutrophils in controls. Although all participants were asymptomatic, seven competitive swimmers, one indoor athlete and one control met the criteria for EIB. CONCLUSION: Our findings show that the intensive training combined with exposure to by-products of chlorination induces airway epithelial damage in competitive swimmers. This is associated with increased damage-associated molecular patterns, innate cytokine release and neutrophilic airway inflammation.

Low cord blood Foxp3/CD3γ mRNA ratios: a marker of increased risk for allergy development.

BACKGROUND: Data from birth cohort studies suggest that increased cord blood total IgE and reduced cord blood regulatory T cells increase the risk of developing allergic sensitization and atopic dermatitis. OBJECTIVE: We here addressed whether serum total IgE and hen's egg-specific IgE levels at birth and at age 1 year differed between healthy and allergic children in a Belgian birth cohort (FONIA). We furthermore studied whether these parameters as well as cord blood Foxp3/CD3γ mRNA levels might predict the allergic outcome. METHODS AND RESULTS: Children (n = 84) were clinically assessed at the ages of 6, 12, 18, and 24 months and at 6 years. Cord blood total IgE levels above 0.35 kU/L predicted early (i.e. before or at the age of 2 years) allergy development. Presence of serum IgE antibodies to hen's egg (cut-off 0.05 Ua/mL) at the age of 1 year was associated with early as well as late (i.e. between the age of 2 and 6 years) allergy development. Cord blood Foxp3/CD3γ mRNA ratios were significantly lower in early allergic children and levels below 0.32 predicted the allergic outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Low cord blood Foxp3/CD3γ mRNA ratios are highly predictive for early allergy development, whereas specific IgE levels to hen's egg white above 0.05 Ua/mL at age 1 year predict allergy development in general.

Sputum cytokine mapping reveals an 'IL-5, IL-17A, IL-25-high' pattern associated with poorly controlled asthma.

BACKGROUND AND OBJECTIVE: Asthma is a heterogeneous disease with various clinical, inflammatory and molecular phenotypes. We studied sputum cytokine mRNA expression patterns in an unselected group of adult asthma patients to characterize the underlying inflammatory process. METHODS: Differential cell counts and cytokine mRNA (quantified by real-time PCR) were analysed on sputum from 40 controls and 66 asthmatic adults. A 'cytokine-high' profile was defined if mRNA levels for that particular cytokine exceeded the 90th percentile value in the control population. Radar graphs were used to visualize cytokine profiles. RESULTS: Sputum mRNA analysis confirmed heterogeneity of cytokine patterns among patients. Thirty-six patients (55%) had a Th2 cytokine pattern: 'IL-5-high' (n = 13), 'IL-4-high' (n = 17) or 'IL-4- and IL-5-high' (n = 6). The 'IL-5-high' asthma profile (n = 13) coincided with the 'IL-25-high' (10/13) and surprisingly also with the 'IL-17A-high' (11/13) profile. The 'IL-5-/IL-25-/IL-17A-high profile was different from the 'IL-4-high' pattern. Patients with the 'IL-5, IL-17A, IL-25-high' pattern had significantly worse lung function parameters. Uncontrolled asthmatics [Asthma Control Test (ACT) < 20] had higher sputum IL-5, IL-17A and IL-25 mRNA levels compared to controlled asthmatics (P = 0.002; P = 0.002; P = 0.066) and uncontrolled asthma is more common among 'IL-5- and IL-17A-high' asthmatics compared to 'IL-5-, IL-17A-low' asthmatics (χ(2) = 3.7, P = 0.027; relative risk (RR): 1.8, 95% CI = 1.1-3.1). CONCLUSIONS AND CLINICAL RELEVANCE: Patients with the 'IL-5, IL-17A, IL-25-high' airway inflammatory pattern are often uncontrolled asthmatics, despite daily treatment. It seems worthwhile to evaluate whether measuring sputum cytokine levels might be used to assess the response to increased doses of steroids in patients with asthma.

Impact of lipoteichoic acid modification on the performance of the probiotic Lactobacillus rhamnosus GG in experimental colitis.

While some probiotic strains might have adjuvant effects in the therapy for inflammatory bowel diseases (IBD), these effects remain controversial and cannot be generalized. In this study, a dltD mutant of the model probiotic Lactobacillus rhamnosus GG (LGG), having a drastic modification in its lipoteichoic acid (LTA) molecules, was analysed for its effects in an experimental colitis model. Dextran sulphate sodium (DSS) was used to induce either moderate to severe or mild chronic colitis in mice. Mice received either phosphate-buffered saline (PBS), LGG wild-type or the dltD mutant via the drinking water. Macroscopic parameters, histological abnormalities, cytokine and Toll-like receptor (TLR) expression were analysed to assess disease activity. LGG wild-type did not show efficacy in the different experimental colitis set-ups. This wild-type strain even seemed to exacerbate the severity of colitic parameters in the moderate to severe colitis model compared to untreated mice. In contrast, mice treated with the dltD mutant showed an improvement of some colitic parameters compared to LGG wild-type-treated mice in both experimental models. In addition, treatment with the dltD mutant correlated with a significant down-regulation of Toll-like receptor-2 expression and of downstream proinflammatory cytokine expression in the colitic mice. These results show that molecular cell surface characteristics of probiotics are crucial when probiotics are considered for use as supporting therapy in IBD.

Type III IFN-lambda mRNA expression in sputum of adult and school-aged asthmatics.

BACKGROUND: The increased susceptibility of asthmatics to rhinovirus infection has recently been related to deficient IFN-lambda 1 (IL-29) and IFN-lambda 2/3 (IL-28) production by bronchial epithelial cells and macrophages. OBJECTIVES: Here, we studied IFN-lambda mRNA expression in the airways of stable asthmatics in comparison with healthy subjects and in relation to asthma symptoms, non-invasive parameters of airway inflammation and lung function parameters. METHODS: Airway cells were obtained by sputum induction, in 14 healthy and 35 asthmatic adults and 12 asthmatic school-aged children. IFN-lambda was studied at the mRNA level by quantitative RT-PCR. RESULTS: Asthmatic adults have increased sputum IL-28 mRNA but similar IL-29 mRNA expression in comparison with healthy subjects. In asthmatics, both sputum IL-28 and IL-29 mRNA expression correlate with the sputum CD3 gamma mRNA expression (reflecting infiltrated T cells). IL-28 (but not IL-29) mRNA levels correlate with the relative and absolute number of eosinophils present in the sputum sample. Sputum IL-29 mRNA (but not IL-28) correlates negatively with asthma symptoms in steroid-naive patients and is significantly higher in steroid-treated than in steroid-naive patients. Finally, both IL-28 and IL-29 mRNA levels are higher in asthmatic children than in asthmatic adults. CONCLUSION: Our results show that asthmatic subjects have substantial type III IFN-lambda mRNA levels in the airways. Our data furthermore suggest that IL-29 could have an immunoprotective role in the lower airways.

The role of interleukin-17 during acute rejection after lung transplantation.

Acute rejection (AR) is an important complication that can occur after lung transplantation and constitutes a risk factor for bronchiolitis obliterans syndrome, which is characterised by a neutrophilic airway inflammation. The specific aim of this study was to investigate the role of interleukin (IL)-17, which promotes chemotaxis of neutrophils by inducing IL-8 production, in AR. Cell differentials, mRNA and protein levels were quantified in bronchoalveolar lavages (BALs) taken from patients at 28 and 90 days after lung transplantation. The patient's rejection status was assessed by transbronchial biopsy. An AR was found in nine out of the 26 patients examined, 28 days after transplantation. The number of BAL neutrophils and lymphocytes were increased in these patients. IL-17 mRNA and protein levels in the BAL were increased in patients with AR. Analysis of BAL obtained at day 90 after transplantation, demonstrated that the increase in IL-17 had disappeared, whereas the increase in neutrophils and lymphocytes persisted. These data showed that interleukin-17 is temporarily upregulated in bronchoalveolar lavage during acute rejection. The number of lymphocytes and neutrophils are increased in bronchoalveolar lavage during acute rejection and may persist up to 2 months after acute rejection. These findings suggest that interleukin-17 is important in the pathophysiology of acute lung rejection.

Evaluation of airway inflammation by quantitative Th1/Th2 cytokine mRNA measurement in sputum of asthma patients.

BACKGROUND: Asthma is a chronic inflammatory disorder of the airways driven by T cell activation. Th2 cells and their cytokines are thought to play a role in the pathophysiology of allergic as well as non-allergic asthma. METHODS: Airway cells were obtained by sputum induction from 15 healthy and 39 asthmatic individuals and the airway T cell cytokine profiles (interleukin (IL)-4, IL-5, IL-13, IL-10 and interferon (IFN)-gamma) at the mRNA level were studied by real time RT-PCR. RESULTS: Asthma patients had increased expression of IL-5 (p = 0.001) and IL-13 (p = 0.03) mRNA in sputum compared with non-asthmatic controls. IL-4 mRNA and IFN-gamma mRNA were detectable in the sputum of 44% and 21% of patients, respectively, but not in controls. Sputum IL-10 mRNA levels did not differ significantly between patients and controls. Sputum mRNA expression levels of IL-4, IL-5, and IL-13 were significantly correlated with the percentage of eosinophils and were higher in subjects with allergic asthma than in those with non-allergic asthma (p = 0.03, p = 0.02 and p = 0.0002, respectively); they did not differ between mild asthmatic subjects and those with moderate to severe asthma. In contrast, IFN-gamma mRNA expression was higher in non-allergic than in allergic patients (p = 0.04) and higher in patients with moderate to severe asthma than in those with mild asthma (p<0.01). Sputum IL-5 mRNA levels (but not the other cytokine mRNA levels) were also correlated with exhaled nitric oxide (eNO) and with bronchial hyperreactivity expressed as the histamine concentration resulting in a 20% decrease in forced expiratory volume in 1 second. CONCLUSION: Real time RT-PCR analysis of mRNA in induced sputum confirms a predominance of Th2 cytokines in both allergic and non-allergic asthma. IL-5 levels reflect eosinophil infiltration as well as eNO levels and hyperreactivity, and levels of the Th1 cytokine IFN-gamma indicate asthma severity. The technique is a promising tool for use in further studies of asthma severity and disease activity.

House dust mite-specific T cells in healthy non-atopic children.

BACKGROUND: T-helper type 2 (Th2) cells play an important role in the pathogenesis of allergic diseases. Recent studies have demonstrated that allergen-specific T cells can also be found in the blood of healthy individuals. Both IL-10 and IFN-gamma might modulate the induction and maintenance of allergen-specific tolerance. AIM: To study the phenotype and functional characteristics of allergen-specific T cells in healthy non-atopic children. METHODS: Peripheral blood mononuclear cells (PBMC) from 13 symptomatic house dust mite (HDM)-allergic children and from nine matched healthy control children were stimulated with recombinant (r)Der p 2, a major allergen from HDMs. RESULTS: Stimulation with rDer p 2 resulted in Th2 cytokine production in cultures of PBMC from allergic but not from healthy children. In contrast, IL-10 and IFN-gamma were induced in PBMC cultures from both healthy and HDM-allergic children. Intracellular staining revealed that IL-10 and IFN-gamma are largely produced by the same T cells. Stimulation of T cells from healthy children with rDer p 2 also induced expression of inducible costimulator (ICOS) on a small T cell subset. CONCLUSION: Allergen-specific memory T cells from healthy non-atopic children produce IL-10 and IFN-gamma (but not Th2 cytokines) and express ICOS upon stimulation. These cells might be responsible for a normal immune balance after allergen encounter in non-atopics.

Allergen-specific T cells from birch-pollen-allergic patients and healthy controls differ in T helper 2 cytokine and in interleukin-10 production.

BACKGROUND: T helper (Th)2 cells play an important role in the development of IgE-mediated diseases, with local overproduction of Th2 cytokines (IL-4, IL-5 and IL-13) at the site of allergic inflammation. Furthermore, IL-10 has been suggested to play a modulatory role in the induction and maintenance of allergen-specific tolerance in human atopic diseases. AIM: We studied whether circulating allergen-specific Th2 cells persist outside the season of exposure in patients mono-sensitized to birch pollen and whether healthy control individuals also have allergen-specific Th2 cells. We also studied whether IL-10-producing allergen-specific T cells can be found in circulation either in healthy controls or in allergic patients. METHODS: Blood was drawn outside the birch-pollen season from 15 birch-pollen-allergic patients, with seasonal respiratory symptoms and with (n=12) or without (n=3) oral allergy syndrome, and from 10 matched healthy controls. Peripheral blood mononuclear cells (PBMCs) were stimulated in vitro with recombinant Bet v 1 allergen, control antigen tetanus toxoid (TT) and anti-CD3/CD80. In part of the cultures, rIL-4 was added in order to reinforce the allergen-specific Th2 cell responses. RESULTS: In the presence of rBet v 1, T cells from allergic patients, but not from healthy controls, produced IL-4, IL-5 and IL-13. IL-5 production by patients' T cells was further enhanced by adding more IL-4. In contrast, rBet v 1 together with IL-4-induced significant IL-10 production in control subjects but not in patients. Both Th1 and Th2 cytokines were equally induced by polyclonal stimulation in allergic patients and controls, but in the presence of IL-4, polyclonally induced IL-10 production was lower in the patient group. CONCLUSION: rBet v 1-specific Th2 cells circulate outside the season of exposure in the blood of birch-pollen-allergic subjects but not in healthy controls. Allergen-specific T cells were also demonstrated in controls but these cells produce IL-10 when stimulated with rBet v 1 in the presence of IL-4. Our data reveal a different allergen-induced cytokine profile in birch-pollen-allergic patients vs. controls, and suggest that a regulatory mechanism involving IL-4-induced allergen-specific IL-10 production might be defective in allergic subjects.