Gael Tavernier

Exposure to Dust and Endotoxin in Textile Processing Workers

BACKGROUND Inhalation of cotton-based particulate has been associated with respiratory symptoms and overt lung disease related to endotoxin exposure in some studies. This cross-sectional study measures personal exposure to inhalable dust and endotoxin in the textile industry of Nepal. METHODS This study was conducted in four sectors (garment making, carpet making, weaving, and recycling) of the textile industry in Kathmandu, Nepal. Personal exposure to inhalable dust and airborne endotoxin was measured during a full-shift for 114 workers.   RESULTS Personal exposure to cotton dust was generally low [geometric mean (GM) 0.81 mg m(-3)) compared to the UK workplace exposure limit (WEL) (2.5 mg m(-3)) but with nearly 18% (n = 20) of the workers sampled exceeding the limit. Exposures were lowest in the weaving and the garment sector (GM = 0.30 mg m(-3)), higher in the carpet sector (GM = 1.16 mg m(-3)), and highest in the recycling sector (GM = 3.36 mg m(-3)). Endotoxin exposures were high with the overall data (GM = 2160 EU m(-3)) being more than 20-fold higher than the Dutch health-based guidance value of 90 EU m(-3). The highest exposures were in the recycling sector (GM = 5110 EU m(-3)) and the weaving sector (GM = 2440 EU m(-3)) with lower levels in the garment sector (GM = 157 EU m(-3)). The highest endotoxin concentrations expressed as endotoxin units per milligram inhalable dust were found in the weaving sector (GM = 165 EU mg(-1)). There was a statistically significant correlation between inhalable dust concentrations and endotoxin concentrations (r = 0.37; P < 0.001) and this was particularly strong in the garment (r = 0.82; P = 0.004) and the carpet sector (r = 0.81; P < 0.001).   CONCLUSIONS Inhalable dust exposures measured in the weaving, carpet, and garment sectors were all below the UK WEL for cotton dust. A significant proportion of the measurements from the cotton recycling sector were above the UK WEL suggesting that better hygiene control measures are required. Airborne endotoxin concentrations in all sectors were found to exceed the Dutch health-based guidance limit of 90 EU m(-3) and may be associated with respiratory health effects.

Indoor Air Quality, Environmental Tobacco Smoke and Asthma: A Case Control Study of Asthma in a Community Population

In recent decades the prevalence of asthma has been increasing in Western countries. Altered environment and lifestyle conditions have been implicated but the underlying mechanisms remain unclear. The Indoor Pollutants, Endotoxin, Allergens, Damp and Asthma (IPEADAM) study is a cross-sectional, case control study designed to analyse the home environments of 200 children in Manchester. In this paper the home concentrations and relationships to asthma development have been examined for a variety of indoor agents including environmental tobacco smoke (ETS), nitrogen dioxide (NO2), formaldehyde, volatile organic compounds (VOCs) and damp, which have been reported as potential factors in the development or the exacerbation of asthma. Levels of respirable particles and tobacco specific particles were found to be significantly higher in the homes with smokers present, but there were no differences in the levels of NO2, formaldehyde or VOCs. However, there were no significant differences in the levels of tobacco related pollutants in the homes of children with and without asthma. Similarly there were no statistically significant differences in the levels of NO2, formaldehyde, VOCs, temperature or relative humidity between the homes of children with and without asthma. This study has demonstrated that few differences exist between the home environments of English children, between 4-16 years of age, with asthma and those without the disease. The parameters examined in this study are unlikely to be related to the development of asthma. Avoidance of these pollutants may not be beneficial in preventing the development of asthma in this age group.

An extracellular matrix fragment drives epithelial remodeling and airway hyperresponsiveness

The matrikine PGP is a mediator of pathological epithelial remodeling in asthma. Extracellular matrix extends its influence in asthma The interplay between immune cells and smooth muscle cells in asthma pathogenesis and response to treatment is under increasing scrutiny. Patel et al. focused on how leukotrienes can modulate immune inflammation and airway hypersensitivity. Mice lacking leukotriene A4 hydrolase had exaggerated epithelial remodeling but dampened immune responses in a house dust mite model of asthma. This was due to release of Pro-Gly-Pro (PGP), a component of the extracellular matrix, which was also elevated in the sputum from severe asthmatics in two clinical cohorts. Their results showcase how the extracellular matrix is a dynamic player in disease and reveal a mediator to be targeted in asthma therapy. It is anticipated that bioactive fragments of the extracellular matrix (matrikines) can influence the development and progression of chronic diseases. The enzyme leukotriene A4 hydrolase (LTA4H) mediates opposing proinflammatory and anti-inflammatory activities, through the generation of leukotriene B4 (LTB4) and degradation of proneutrophilic matrikine Pro-Gly-Pro (PGP), respectively. We show that abrogation of LTB4 signaling ameliorated inflammation and airway hyperresponsiveness (AHR) in a murine asthma model, yet global loss of LTA4H exacerbated AHR, despite the absence of LTB4. This exacerbated AHR was attributable to a neutrophil-independent capacity of PGP to promote pathological airway epithelial remodeling. Thus, we demonstrate a disconnect between airway inflammation and AHR and the ability of a matrikine to promote an epithelial remodeling phenotype that negatively affects lung function. Subsequently, we show that substantial quantities of PGP are detectable in the sputum of moderate-severe asthmatics in two distinct cohorts of patients. These studies have implications for our understanding of remodeling phenotypes in asthma and may rationalize the failure of LTA4H inhibitors in the clinic.

Nonadherence with inhaled preventer therapy in severe asthmatic patients on long-term omalizumab

We read with interest the paper by Lee et al. [1], reporting on the high rate of nonadherence in a group of severe asthma patients who were potentially suitable for biological therapy or bronchial thermoplasty. In our experience the issue of nonadherence is not confined to patients under active consideration for biological therapy. We have identified significant rates of nonadherence in a group of patients on long-term Omalizumab therapy. Nonadherence with inhaled preventer therapy is prevalent in previously adherent patients on long-term omalizumab http://ow.ly/5wdE30kp0MM

P243 Specific antibody deficiency to streptococcus pneumoniae and haemophilus influenzae in asthma and fungal disease

Introduction Recurrent exacerbations are a characteristic feature of uncontrolled asthma, often due to viral or bacterial infections. We have reported in a retrospective study that immune deficiency is common in asthma and correlates with reduced lung function. We set up a prospective study to determine if this predisposes to a more severe disease. Aim Our aim is to ascertain if immune deficiency is associated with a more severe disease potentially with radiological changes and clinically with low lung function and frequent exacerbations. Methods We prospectively collected data from new patients attending the regional asthma and fungal clinics. Demographics, markers of disease severity and specific antibody levels to Haemophilus iInfluenzae (HI), and Streptococcus pneumoniae (SP), were recorded. Patients with specific antibody deficiency (HI: ≤ 0.15 iu and SP: ≤ 0.35 iu to 6+ of 12 strains tested) received appropriate vaccination(s) in primary care (Pneumovax® and Meniotrix®), with repeat samples collected two months later. We also recorded blood and sputum eosinophil counts, radiological findings such as bronchiectasis and bronchial wall thickening, total IgE, smoking status, exacerbations in the last year and ITU admissions. Results 101 patients were followed up (69 asthma, 32 fungal) 67 female, mean (SD) age 53 (15) years, FEV1 69 (21.9)% predicted, ICS dose 1818 (1244) μg, and BMI 29.9 (8.9) kg/m2. Specific antibody levels and responses to vaccination are presented in Figure 1. Immune deficiency at baseline and post vaccination did not correlate with lung function, radiological findings such as bronchial wall thickening or exacerbation frequency. Conclusion Specific antibody deficiency is commonly seen in patients with asthma and fungal disease. Vaccination can provide protection and should be considered in this patient group. We need further analysis with a larger cohort of patients to study the association between antibody deficiency, lung function, radiological changes and disease progression. Abstract P243 Figure 1 Specific antibody levels at baseline and following vaccination for Haemophilus influenza and streptococcus pneumonia

S130 Axl receptor tyrosine kinase on airway macrophages has a key role in lung immune homeostasis

Rationale Apoptotic cell uptake (efferocytosis) by airway macrophages (AMs) is critical for lung immune homeostasis and is defective in chronic lung diseases, including asthma,1 although the molecular mechanism behind this remains unknown. The TAM (Tyro3, Axl, MerTK) receptor tyrosine kinases are one of the main receptor classes that mediate efferocytosis but little is known about their regulation and function in inflammatory lung diseases. Aim To investigate expression profile of TAM receptors and their ligand Gas6 in human AMs and analyse potential defects in TAM receptor expression in chronic lung inflammation. Methods AMs from the sputum of patients with asthma (BTS step 3–5) (n = 30) or healthy donors (HD) (n = 12) were enriched by plastic adhesion. Monocytes were isolated from matched whole blood samples by CD14 positive selection and differentiated into monocyte-derived macrophages (MDMs). Total RNA was extracted from all purified cell populations and mRNA expression analysed by qPCR. HD MDMs were stimulated with Th2 cytokines in vitro and TAM receptor expression was analysed using qPCR and ELISA.Abstract S130 Figure 1 mRNA expression of Axl in airway macrophages of healthy donors and patients with asthma Main results Axl was the dominant TAM receptor expressed in HD AMs whereas monocytes and MDMs predominantly expressed MerTK. Axl expression was significantly reduced in AMs from patients with asthma compared to HD (p < 0.0001), while mRNA levels of MerTK and Gas6 was similar in both groups. We found no differences in Axl and MerTK expression in monocytes and MDMs from HD and patients with asthma, indicating that the observed differences were restricted to the site of inflammation. In vitro, MDM stimulation with IL-4 or IL-13 downregulated Axl mRNA and protein expression in a time-dependent manner. Conclusions We have shown for the first time that Axl is the principal TAM receptor expressed in human AMs. Significant reduction of Axl expression in AMs from patients with asthma might be responsible for inefficient clearance of apoptotic cells from the inflamed airways and contribute to persistent airway inflammation. Strategies aimed at restoration of Axl expression or activity may represent a novel therapeutic strategy in asthma and other chronic lung diseases. Reference 1 Simpson JL, Gibson PG, Yang IA et al. Impaired macrophage phagocytosis in non-eosinophilic asthma. Clin Exp Allergy. 2013;43:29–35

P159 The use of omalizumab in severe asthma is associated with a decline in blood eosinophils

Introduction/aim Omalizumab (Xolair) is a recombinant humanised monoclonal antibody licensed for the treatment of severe allergic asthma patients with IgE mediated disease. The mechanism of action of omalizumab is to bind to IgE preventing interaction with FCERI (high affinity receptors) upon the surface of mast cells and basophils, thereby reducing the activation of the inflammatory cascade and associated clinical symptoms. Although blood eosinophilia is a useful measure of airway inflammation, the correlation between blood eosinophils and omalizumab treatment has not been described outside clinical trial. Therefore, our aims were to identify whether the introduction of omalizumab is associated with a change in the blood eosinophil count within our cohort of patients with severe asthma. Methods We collected measurements of blood eosinophils in patients maintained on omalizumab for periods 12 months pre and post, and (where available) 24 months pre and post initiation of therapy. We also investigated any correlation between blood eosinophils pre and post treatment versus clinical parameters including total IgE and omalizumab dose. Results Complete data sets including 12-month blood eosinophil data were available for 49 of our current cohort of 92 patients on treatment. The mean blood eosinophil count dropped from 0.33 × 109cells/l (IQR 0.37) × 109cells/l pre-treatment to 0.22 × 109cells/l (IQR 0.30) post treatment (p = <0.001). Additionally, we widened the window to 24 months pre and post initiation of treatment, if blood eosinophil data was not available at 12 months. Data for 59 patients demonstrated similar significant reduction in mean blood eosinophil, 0.34 × 109cells/l (IQR 0.34) pre-treatment to 0.23 × 109cells/l (IQR 0.29) ( p = 0 .003). No association was seen between the changes in mean blood eosinophil counts post treatment versus total monthly omalizumab dose and baseline total IgE. Conclusion Our data demonstrates a significant reduction in blood eosinophils in patients who are receiving omalizumab treatment when comparing blood eosinophils at 12 and 24 months pre and post treatment. Future work should investigate whether this is a direct result of omalizumab therapy, due to confounding by other treatment, or a marker of improved asthma control.

P74 Prevalence of Specific Antibody Deficiency in Severe Asthma

Introduction Patients with asthma are prone to recurrent infective exacerbations, due to viral or bacterial infections. We have previously presented retrospective data, demonstrating significantly reduced lung function in severe asthma patients with specific antibody deficiency. The prevalence and impact of specific antibody deficiency in this patient group is not known. Aim We aimed to determine the prevalence of specific antibody deficiency and its association with markers of disease severity. Methods We prospectively collected data from all new patients attending the regional severe asthma clinic. We recorded demographic details and markers of disease severity including: BTS treatment step, inhaled corticosteroid (ICS) dose, spirometry, blood and sputum eosinophil count, radiological findings such as bronchiectasis and bronchial wall thickening, exacerbations in the last year and ITU admissions. Specific antibody levels to Haemophilus Influenzae (Streptococcus Pneumoniae (<0.35 μg/ml to at least 6 of the 12 serotypes classed as deficient) were measured. Results Data for 53 patients (39F), mean (SD) age 49.6 (15.9) years were available. Mean (SD) FEV1 was 69 (22)% predicted, ICS dose 1914 (1337) micrograms, and BMI 31.5 (8.6) kg/m2. All were at BTS step 3–5. Information on specific antibody levels was available for 43 and 45 patients for H Influenzae and S pneumoniae respectively and for both in 42 patients. Overall out of the 42 patients 35 (83%) were deficient to one or both the organisms. Of these 13 (31%) were deficient to H Influenzae alone, 5(12%) to S pneumoniae alone, and 17 (40.5%) to both. Looking at each organism separately 30 (70%) out of 43 were deficient to H Influenzae and 23 out of 45 (51%) were deficient to S pneumoniae. Of the 32 patients for whom data were available 20 (63%) had 7 or more exacerbations in the preceding year and two thirds of these had bronchial wall thickening on their CT scans. A third of patients (30%) reported at least one ITU admission. The presence of specific antibody deficiency did not correlate with any clinical or radiological findings.Abstract P74 Table 1 Prevalence of specific antibody deficiency and associated patient characteristics Prevalence Bronchial wall thickening on CT chest Bronchiectasis on CT chest ≥7 Exacerbations past year Total ITU admissions Percentage predicted FEV1 (%) Inhaled steroid (BDP equivalent) µg n = 45 n (%) n (%) n (%) n (%) n (%) Mean (SD) Mean (SD) Total H. influenzae deficient 30 (70) H. influenzae deficient alone 13 (31) 8 (23) 5 (5) - 14 4 (3) - 17 3 (3) - 18 57 (16) 2540 (2240) Total S. pneumoniae deficient 23(51) S. pneumoniae deficient alone 5 (12) 3 (8.5) 2 (2) - 6 1 (0) - 4 0 (2) - 0 77 (8) 1933 (1101) Combined Deficiency 17 (40) 11 (31) 6 (10) - 17 8 (3) - 33 4 (2) - 24 73 (23) 1837 (900) Competent Specific Antibody Levels 7 (13) 2 (6) 3 (2) - 8.5 2 (3) - 6 0 (3) - 0 70 (32) 1840 (607) Conclusion Specific antibody deficiency to H influenza and S pneumoniae is remarkably common in moderate to severe asthma. Further studies are required to determine the clinical significance of this finding.

P73 A pilot study to investigate the use of serum inhaled corticosteroid concentration as a potential marker of treatment adherence in severe asthma

Background Inhaled anti-inflammatory therapy is fundamental to asthma management, but adherence is very poor. This increases the risk of exacerbations and poor symptom control. Currently there is no direct way of assessing adherence to inhaled steroids accurately. The primary aim of this project was to determine whether liquid chromatography tandem mass spectrometry could be used to detect fluticasone propionate (FP) in human serum as a potential aid to therapeutic monitoring. The secondary aim was to relate serum levels of FP to markers of asthma severity. Methods We collected blood samples over an 8 hr period from inpatients with severe asthma on a stable dose of inhaled FP. Following baseline (trough) sampling, patients were observed using their inhaler, with inhaler technique documented. Subsequent samples were obtained 1, 2s, 4 and 8 hrs post inhalation. Demographic details and spirometry were also recorded. Results Thirteen patients were recruited: 8 males, 5 females; age range 22–64 yrs; FEV1 range 53–101% predicted; 10 patients on 1000 mcg/day, and three on 2000 mcg/day FP. The mean concentration of FP at 1 hr post inhaler (peak in 7/13 patients) was 95.5 (SD 89.1) ng/L. The mean pre-dose trough concentration was 32.9 (SD 41.5) ng/L. Two patients were noted to have poor inhaler technique; these patients had some of the lowest serum FP levels recorded. The FEV1% predicted was found to be strongly correlated with the peak serum FP concentration (Pearson’s r = 0.8, p = 0.001). Conclusion We have demonstrated that FP can be detected in the blood of patients with severe asthma following directly observed therapy; this could have a potential future application as a direct measure of adherence and perhaps inhaler technique. We also demonstrated a profound effect of reduced lung function predicting low serum FP levels. Future work will explore whether poor absorption reflects relatively poor efficacy in the most severe patients.Abstract P73 Figure 1 Serum concentration of FP at sampling timepoints; dashed lines represent individual patients; solid line group mean

P180 Sputum eosinophil positivity to tailor steroid management of severe asthmatics

The use of sputum eosinophil count in asthma clinics is rapidly expanding as it has been reported as being a useful indicator of the worsening of asthma symptoms and that its normalisation reduces asthma exacerbations and admissions. Without additional steroids, levels of sputum eosinophils have been shown to be highly variable in severe asthmatic patients. Furthermore, precise patient phenotyping is increasingly becoming important as our understanding of the physiopathology of severe asthma widens. We introduced sputum differential cell counting in our severe asthma clinic, with a view to first reducing sputum eosinophils below 3% by augmenting anti-inflammatory therapy, and attempting steroid withdrawal once patients became sputum eosinophil negative (E−). To date, 264 patients have been investigated for sputum eosinophils, using induction with nebulised sodium chloride if necessary and suitable. This paper presents our yearly update of the anti-inflammatory (steroid) therapy of the first successive patients with at least two successful sputum counts (current n=71), specifically investigating patients’ management in the light of their positive sputum eosinophil levels at baseline assessment. Twenty patients were sputum eosinophil positive (E+) on their initial visit and 25 had reduced eosinophil levels (p=0.001) on a subsequent visit, including 14 becoming E−. Nineteen were offered a trial of steroid augmentation: 11 patients with a trial of IM triamcinolone (all patients had subsequent reduced eosinophils levels, 9 becoming E−, p=0.003); 5 patients with increased oral prednisolone treatment (four patients with reduced eosinophils levels, one becoming E−); 3 with increased inhaled steroid therapy (all with reduced eosinophil levels, 1 becoming E−). 66% of patients with uncontrolled sputum eosinophilia were treated with an increase in anti-inflammatory maintenance therapy. Sputum eosinophil levels decreased for 95% of these as already reported, but only 11/19 achieved full control of sputum eosinophilia with 2/11 failing to normalise eosinophils despite IM triamcinolone (representing a population of confirmed steroid resistance. Sputum eosinophil negativity used as a surrogate marker for asthma control has been shown to be an essential tool in identification and management of patients with asthma at risk of deterioration and admission.