Fiona A Symon | University of Leicester (original) (raw)

Papers by Fiona A Symon

ABSTRACTRationaleThe effects of inhaled corticosteroids (ICS) on healthy airways are poorly defin... more ABSTRACTRationaleThe effects of inhaled corticosteroids (ICS) on healthy airways are poorly defined.ObjectivesTo delineate the effects of ICS on gene expression in healthy airways, without confounding caused by changes in disease-related genes and disease-related alterations in ICS-responsiveness.MethodsRandomised open-label bronchoscopy study of high dose ICS therapy in 30 healthy adult volunteers randomised 2:1 to i) fluticasone propionate 500 mcg bd or ii) no treatment, for 4 weeks. Laboratory staff were blinded to allocation. Biopsies and brushings were analysed by immunohistochemistry, bulk RNA sequencing, DNA methylation array and metagenomics.Measurements and main resultsICS induced small between-group differences in blood and lamina propria eosinophil numbers, but not in other immunopathological features, blood neutrophils, FeNO, FEV1, microbiome or DNA methylation. ICS treatment upregulated 72 genes in brushings and 53 genes in biopsies, and downregulated 82 genes in brushi...

Airway cell biology and immunopathology

Proceedings of the National Academy of Sciences, 2021

Significance Coexposure to airborne pollen enhances susceptibility to respiratory viral infection... more Significance Coexposure to airborne pollen enhances susceptibility to respiratory viral infections, regardless of the allergy status. We hypothesized this could be also true for SARS-CoV-2 infections. To investigate this, we tested for relationships between SARS-CoV-2 infection rates and pollen concentrations, along with humidity, temperature, population density, and lockdown effects. Our unique dataset derives from 130 sites in 31 countries and across five continents. We found that pollen, sometimes in synergy with humidity and temperature, explained, on average, 44% of the infection rate variability. Lockdown halved infection rates under similar pollen concentrations. As we cannot completely avoid pollen exposure, we suggest wide dissemination of pollen−virus coexposure information to encourage high-risk individuals to wear particle filter masks during high springtime pollen concentrations.

but not neutrophils, to human umbilical vein endothelial cells under flow

Blood, 2000

Selective eosinophil accumulation is a hallmark of diseases such as asthma. In a model of chronic... more Selective eosinophil accumulation is a hallmark of diseases such as asthma. In a model of chronic eosinophilic inflammation, we have previously shown that the tethering step in eosinophil adhesion is mediated by PSGL-1 binding to P-selectin. The Th2-associated cytokine IL-13 is of potential importance in allergic disease. We have therefore investigated whether IL-13 can mediate eosinophil binding to human umbilical vein endothelial cells (HUVEC) through P-selectin. IL-13 caused dose- and time-dependent increases of P-selectin expression, as assessed by flow and laser scanning cytometry. A similar degree of expression was observed with IL-4. There was no effect on E-selectin or ICAM-1 expression. Tumor necrosis factor- induced the expression of VCAM-1, E-selectin, and ICAM-1 but had no effect on P-selectin expression. IL-13 increased the production of mRNA for surface and soluble variants of P-selectin. Under flow conditions, eosinophils, but not neutrophils, showed enhanced binding...

Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology, Jan 10, 2017

Patients with severe asthma appear relatively corticosteroid resistant. Corticosteroid responsive... more Patients with severe asthma appear relatively corticosteroid resistant. Corticosteroid responsiveness is closely related to the degree of eosinophilic airway inflammation. The extent to which eosinophilic airway inflammation in severe asthma responds to treatment with systemic corticosteroids is not clear. To relate the physiological and inflammatory response to systemic corticosteroids in asthma to disease severity and the baseline extent of eosinophilic inflammation. Patients with mild/moderate and severe asthma were investigated before and after two-weeks of oral prednisolone (Clintrials. gov NCT00331058 and NCT00327197). We pooled the results from 2 studies with common protocols. The US study contained 2 independent centres and the UK 1 independent centre. The effect of oral corticosteroids on FEV1 , Pc20, airway inflammation and serum cytokines were investigated. Baseline measurements were compared with healthy subjects. 32 mild/moderate asthmatics, 50 severe asthmatics and 35 ...

Journal of immunology (Baltimore, Md. : 1950), Jun 15, 2016

Eosinophils play an important role in the pathogenesis of asthma and can be activated by extracel... more Eosinophils play an important role in the pathogenesis of asthma and can be activated by extracellular nucleotides released following cell damage or inflammation. For example, increased ATP concentrations were reported in bronchoalveolar lavage fluids of asthmatic patients. Although eosinophils are known to express several subtypes of P2 receptors for extracellular nucleotides, their function and contribution to asthma remain unclear. In this article, we show that transcripts for P2X1, P2X4, and P2X5 receptors were expressed in healthy and asthmatic eosinophils. The P2X receptor agonist α,β-methylene ATP (α,β-meATP; 10 μM) evoked rapidly activating and desensitizing inward currents (peak 18 ± 3 pA/pF at -60 mV) in healthy eosinophils, typical of P2X1 homomeric receptors, which were abolished by the selective P2X1 antagonist NF449 (1 μM) (3 ± 2 pA/pF). α,β-meATP-evoked currents were smaller in eosinophils from asthmatic patients (8 ± 2 versus 27 ± 5 pA/pF for healthy) but were enhanc...

Clinical Experimental Allergy, Nov 1, 1995

Eosinophil-derived inflammatory mediators including cytokines are considered to be important in t... more Eosinophil-derived inflammatory mediators including cytokines are considered to be important in the pathogenesis of allergic inflammation. Fibronectin (Fn) has been shown to be a physiological trigger of autocrine cytokine production by human eosinophils. Fn is encoded by a single gene, but alternate splicing of the primary RNA transcript results in polypeptide diversity in a cell type-specific fashion. Thus, tissue Fn contains approximately 50% more of the CS-1 cell binding region recognized by the integrin alpha 4 beta 1 compared with plasma Fn. Since eosinophils are predominantly tissue-dwelling cells we compared the effect of tissue and plasma Fn on eosinophil survival in culture. The viability and cytokine generation of eosinophils (> 99.9% pure) cultured for up to 4 days in 96 well plates coated with tissue Fn, plasma Fn or BSA was compared. There was a significant difference in the ability of tissue Fn to support eosinophil survival compared with plasma Fn (P < 0.01). Optimal survival with tissue Fn was seen at 25 micrograms/well (70% +/- 2.0% viability at 3 days vs 7% +/- 2.2% viability on BSA). Significant (P < 0.001) cell viability on tissue Fn was observed for up to 4 days in culture (54% +/- 6.0%) compared with BSA coated wells. Addition of autologous mononuclear cells (final concentration 0.5%, 1% or 2%) resulted in plasma Fn-dependent eosinophil survival comparable to that of 99.9% pure eosinophils adherent to tissue Fn. Tissue Fn-dependent survival was significantly inhibited by anti-interleukin-3, anti-granulocyte macrophage colony stimulating factor (GM-CSF) and anti-IL-5 monoclonal antibodies. Picogram quantities of these three cytokines were detected in supernatants from eosinophils cultured for 3 days on tissue Fn using specific enzyme-linked immunosorbent assays (ELISAs). Eosinophil survival on tissue Fn was significantly inhibited by anti-beta 1 and alpha 4 beta 1 monoclonal antibody (MoAb) and also by a MoAb specific for the CS-1 motif in the IIICS region of Fn. These observations show preferential survival of eosinophils cultured on tissue Fn as a result of alpha 4 beta 1-dependent interaction with the CS-1 region of tissue Fn triggering autocrine cytokine synthesis and release, thereby promoting their survival and persistence within the tissues.

Thorax, 1999

Background-Sputum induction is an important non-invasive technique for measuring airway inflammat... more Background-Sputum induction is an important non-invasive technique for measuring airway inflammation in asthma. Cell numbers are often too low for flow cytometric analysis. Laser scanning cytometry (LSC) is a novel technique that allows objective multicolour fluorescence analysis of cells on a microscope slide. Methods-LSC was used to determine sputum eosinophil and bronchial epithelial cell counts. We first confirmed that we could measure eosinophil counts accurately in peripheral blood using-major basic protein (MBP) immunofluorescent staining. Sputum induction was performed according to standard protocols. Sputum samples from eight normal controls and 12 asthmatic patients were analysed by LSC and manual counting by two independent observers. Octospot cytospins were fixed and stained with mouse-human-MBP monoclonal antibody or mouse-human-cytokeratin antibody and goat-mouse Oregon Green conjugated second antibody. Results-Sputum induction provided a mean (SE) of 0.99 (0.2) × 10 6 cells per donor. More than 3000 cells on three cytospins per slide were analysed per cell type. The intraclass correlation coefficient (R) and standard deviation (SD) of diVerences in eosinophils determined by manual counting and LSC were 0.9 and 2.1, respectively, and for bronchial epithelial cell counts they were 0.7 and 2.0. Selective detection of labelled cells was confirmed visually after relocation. Conclusion-Eosinophils and bronchial epithelial cells can be accurately and reproducibly counted in an objective manner. LSC is therefore a potentially powerful new method for immunophenotyping leucocytes and epithelial cells objectively in induced sputum in patients with asthma.

Thorax, 2003

Background: We have recently reported a strong association between organ specific autoimmune dise... more Background: We have recently reported a strong association between organ specific autoimmune disease and idiopathic chronic cough and have suggested that cough may be caused by airway inflammation secondary to aberrant homing of activated lymphocytes to the lung. An immunopathological study was undertaken to test the hypothesis that idiopathic chronic cough is associated with lymphocytic airway inflammation. Methods: Bronchoscopy, bronchial biopsies, bronchoalveolar lavage (BAL), and peripheral blood and BAL flow cytometry were performed in 19 patients with idiopathic chronic cough, 14 with explained chronic cough, and 11 normal subjects. Results: Organ specific autoimmune disease or positive autoantibodies were present in eight of the 19 patients with idiopathic cough, in one of the 14 patients with explained cough, and in one of the 11 normal subjects. Median BAL fluid differential lymphyocyte counts were significantly higher in patients with idiopathic cough (10.0%) than in normal subjects (6.3%, 95% confidence interval of difference 1.5 to 11.9, p = 0.01) or patients with explained cough (5.2%, 95% CI of difference 2.0 to 10.4, p = 0.001). There were no differences in bronchial biopsy T lymphocyte counts between the groups. The mean (SE) proportion of CD3+ peripheral blood mononuclear cells expressing CD4 was significantly higher in normal subjects than in patients with idiopathic cough (69 (3)% v 58 (3)%, mean difference 11%, 95% CI of difference 2 to 20, p,0.02) but not than those with explained chronic cough (63 (2)%). There were no differences in BAL T lymphocyte phenotype between groups. Conclusion: BAL fluid lymphocytosis occurs in some patients with idiopathic chronic cough. The association of idiopathic chronic cough with organ specific autoimmune disease raises the possibility that this might be caused by lymphocyte homing from the primary site of autoimmune inflammation or the result of an autoimmune process in the lung.

Thorax, 2003

Background: Eosinophilic bronchitis is a condition characterised by a corticosteroid responsive c... more Background: Eosinophilic bronchitis is a condition characterised by a corticosteroid responsive cough, sputum eosinophilia, and normal tests of variable airflow obstruction and airway responsiveness. We performed a detailed comparative immunopathological study to test the hypothesis that the different airway function in patients with eosinophilic bronchitis and asthma reflects differences in the nature of the lower airway inflammatory response. Methods: Exhaled nitric oxide was measured and induced sputum, bronchoscopy, bronchial wash (BW), bronchoalveolar lavage (BAL), and bronchial biopsy were performed in 16 subjects with eosinophilic bronchitis, 15 with asthma, and 14 normal controls. Results: Both eosinophilic bronchitis and asthma were characterised by an induced sputum, BW and BAL eosinophilia, an increased number of epithelial and subepithelial eosinophils, and increased reticular basement membrane thickness. The median concentration of exhaled nitric oxide was higher in those with eosinophilic bronchitis (12 ppb) or asthma (8.5 ppb) than normal controls (2 ppb) (95% CI of the difference 5 to 16, p<0.0001 and 2 to 11.3, p=0.004, respectively). There were no group differences in epithelial integrity or the number of subepithelial T lymphocytes, mast cells or macrophages. Conclusion: With the exception of our previously reported association of smooth muscle mast cell infiltration with asthma, the immunopathology of eosinophilic bronchitis and asthma are similar which suggests that eosinophilic airway inflammation, increased exhaled nitric oxide, and increased basement membrane thickening are regulated independently of airway hyperresponsiveness.

New England Journal of Medicine, 2002

Background Asthma and eosinophilic bronchitis are characterized by similar inflammatory infiltrat... more Background Asthma and eosinophilic bronchitis are characterized by similar inflammatory infiltrates in the submucosa of the lower airway. However, eosinophilic bronchitis differs from asthma in that there is no variable airflow obstruction or airway hyperresponsiveness in the former condition. We tested the hypothesis that there were differences between the two conditions in the microlocalization of mast cells within the airway smooth muscle. Methods Immunohistochemical analysis of bronchial-biopsy specimens was completed in 17 subjects with asthma, 13 subjects with eosinophilic bronchitis, and 11 normal controls recruited from two centers. Results Both groups with disease had a similar degree of submucosal eosinophilia and thickening of the basement membrane and lamina reticularis. By contrast, the number of tryptase-positive mast cells in the bundles of airway smooth muscle from subjects with asthma (median, 5.1 mast cells per square millimeter of smooth muscle [range, 0 to 33.3]) was substantially higher than that in subjects with eosinophilic bronchitis (median, 0 mast cells per square millimeter; range, 0 to 4.8) and that in normal controls (median, 0 mast cells per square millimeter [range, 0 to 6.4]; P<0.001 for the comparison among the three groups). T cells and eosinophils were not usually seen in the airway smooth muscle in any of the groups. Conclusions The infiltration of airway smooth muscle by mast cells is associated with the disordered airway function found in asthma. (

The Journal of Immunology, 2001

The lung is an important tertiary lymphoid organ with constant trafficking of T cells through the... more The lung is an important tertiary lymphoid organ with constant trafficking of T cells through the lung in both health and disease. T cell migration is controlled by a combination of adhesion receptors and chemokines expressed on vascular endothelium and in the tissue, often in an organ-specific manner. This leads to selective accumulation of different T cell subsets, a process called lymphocyte homing. There is evidence for a distinct lung-homing pathway, but no specific lung-homing receptors have been described. We analyzed the chemokine receptor profile of lung T cells to determine the extent to which lung T cells shared homing pathways with other organs such as the gut and skin. In addition, we compared expression of receptors in normal and asthmatic individuals to determine whether different pathways were used in health and disease. We observed that lung T cells expressed a profile of chemokine and adhesion receptors distinct from that of gut-and skin-homing T cells although no chemokine receptor specific for the lung was found. In particular, lung T cells expressed CCR5 and CXCR3, but not CCR9 or cutaneous lymphocyte Ag, and only low levels of CCR4 and ␣ 4 ␤ 7. No differences were observed between lung T cells from normal vs asthmatic subjects. This study provides added support for the concept of a lung-homing pathway separate from other mucosal organs such as the gut and suggests that the chemokine pathways that control T cell migration in normal homeostasis and Th2-type inflammatory responses are similar.

Journal of Experimental Medicine, 1994

Tissue eosinophilia is a characteristic feature of a number of inflammatory diseases including as... more Tissue eosinophilia is a characteristic feature of a number of inflammatory diseases including asthma and nasal polyposis. Eosinophil migration into tissues is controlled in part by interactions between eosinophil adhesion receptors and counter-structures on the vascular endothelium. To determine the receptors used by eosinophils to adhere to vascular endothelium in allergic inflammation we have adapted the Stamper-Woodruff frozen section assay (FSA) to study eosinophil adhesion to nasal polyp endothelium. Immunohistology indicated that intercellular adhesion molecule 1 (ICAM-1), E-selectin and P-selectin were well expressed by nasal polyp endothelium, whereas expression of vascular cell adhesion molecule 1 (VCAM-1) was weak or absent. Unstimulated human peripheral blood eosinophils adhered specifically to nasal polyp endothelium. Adherence was temperature and divalent cation-dependent and saturable at cell densities > 5 x 10(6) cells/ml. Eosinophil adhesion was almost completely...

Journal of Allergy and Clinical Immunology, 2002

Background: Asthma is characterized by variable airflow obstruction and airway hyperresponsivenes... more Background: Asthma is characterized by variable airflow obstruction and airway hyperresponsiveness in association with airway inflammation under the influence of T H 2 cytokines. Eosinophilic bronchitis has similar immunopathology to asthma but without disordered airway physiology. Whether eosinophilic bronchitis is associated with increased expression of T H 2 cytokines is unknown. Objective: We sought to assess the expression of T H 2 cytokines in eosinophilic bronchitis. Methods: Expression of activation markers and chemokine receptors from blood and bronchoalveolar lavage (BAL) fluid T cells and the T H 2 cytokine expression from these T cells and bronchial mucosa biopsy specimens were assessed from subjects with eosinophilic bronchitis, subjects with asthma, and healthy control subjects. Results: The proportion of resting (stimulated) CD4 BAL fluid T cells expressing intracellular IL-4 was significantly higher in the subjects with eosinophilic bronchitis 7.2% (11.4%) and subjects with asthma 5.3% (5.5%) than in healthy control subjects 2.8% (3.9%) (P = .03). The number of IL-4 + (P < .001) and IL-5 + (P = .003) cells per square millimeter of bronchial submucosa was significantly higher in the disease groups than in the healthy control subjects. Expression of intracellular IFN-γ was significantly higher in stimulated blood CD8 T cells from subjects with eosinophilic bronchitis (24%) and asthma (17%) than in the healthy control subjects (5%; P = .003). There were no between-group differences in expression of IFN-γ in the BAL fluid T cells or in the bronchial submucosa and no differences in expression of activation markers or chemokine receptors. Conclusion: These findings support the concept of asthma as a disease associated with activation of T H 2 lymphocytes in the airway and provide evidence that these cytokines play a role in the development of airway inflammation in eosinophilic bronchitis but suggest that the release of T H 2 cytokines is not sufficient for the elaboration of disordered airway physiology in asthma. (J Allergy Clin Immunol 2002;110:899-905.)

Journal of Allergy and Clinical Immunology, 2005

Background: The concept of the polarization of chemokine receptor expression by T H 1 and T H 2 c... more Background: The concept of the polarization of chemokine receptor expression by T H 1 and T H 2 cells provides an attractive mechanism for their differential recruitment to tissue, which could be subject to disease-specific therapeutic intervention. The paradigm that T H 1 cells preferentially express CXCR3 and CCR5 and T H 2 cells preferentially express CCR3, CCR4, and CCR8 has been well established in the setting of in vitro polarized cell lines; however, the situation in vivo appears less clear-cut. Objective: We sought to investigate whether this pattern of polarization can be demonstrated in human lung tissue. Methods: We used single-cell analysis to investigate the relationship between chemokine receptor expression and cytokine production on peripheral blood and bronchoalveolar lavage fluid T cells in patients with asthma, a putative T H 2 disease, as well as in healthy control subjects. Results: We have found in both asthmatic and control subjects that IL-4-expressing blood and bronchoalveolar lavage fluid T cells are significantly more likely to express the T H 2 type 2 chemokine receptors CCR3 and CCR4, with 10-fold and 2-fold differences in expression, respectively, compared with IFN-g-expressing cells. Conclusion: We have provided evidence that polarization of T H 2-type chemokine receptors on IL-4-expressing cells can be demonstrated in an in vivo setting and therefore that these cells might indeed be susceptible to differential patterns of recruitment as a result of expression of the relevant chemokines at inflammatory sites.

Journal of Allergy and Clinical Immunology, 2002

Eosinophilic bronchitis (EB) is a common cause of chronic cough characterised by a sputum eosinop... more Eosinophilic bronchitis (EB) is a common cause of chronic cough characterised by a sputum eosinophilia. In contrast to asthma there is no variable airflow obstruction or airway hyperresponsiveness. Eosinophilic airway inflammation in asthma is under the control ofTh2 cytokines, whereas the cytokine regulation of the inflammatory response in eosinophilic bronchitis is unknown. We hypothesised that the differences in airway pathophysiology between these two conditions may be related to cytokine expression by airway T-cells. From 10 subjects with EB, 9 with asthma and 9 normal controls 20ml of venous blood was taken and the subjects underwent a fibreoptic bronchoscopy and 180ml bronchoalveolar lavage (BAL) to the middle lobe. The peripheral blood mononuclear cell (PBMC) fraction was obtained by centrifugation on Ficoll. After washing PBMC and BAL cells were either stimulated with PMA, calcium ionophore and Brefeldin A or incubated in culture medium alone (resting) for 4hr at 37°C. The cells were fixed, incubated with CD3-F1TC/RPE and CD8-PerCP, permeabilised and labelled with IL-4-RPE and IFN-y-FITC or isotypic controls and analysed using three-colour flow cytometry. The median (range) % of stimulated CD4+ PBMC expressing IFN-y were increased in those subjects with EB 14 (2.8-52) and asthma 15 (7-30) compared to normals 3.3 (0.1-12) (Kruskal-Wallis p=0.024). Expression of 1L-4 was increased in EB and asthma compared to normals in both the resting (p=0.03) and stimulated (p=0.045) CD4+ BAL cells (Table). There were no between group differences in IL-4 expression in PBMC cells or IFN-yin BAL cells. In conclusion, increased Th2 cytokine expression by BAL T-cells is a feature of EB and asthma suggesting that they play a role in the airway inflammation observed in EB but that release of Th2 cytokines is not important in the development of disordered airway physiology in asthma. Median (range) % CD4+ BAL T-cells expressing intracellular cytokines

Airway cell biology and immunopathology

Proceedings of the National Academy of Sciences, 2021

but not neutrophils, to human umbilical vein endothelial cells under flow

Blood, 2000

Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology, Jan 10, 2017

Journal of immunology (Baltimore, Md. : 1950), Jun 15, 2016

Clinical Experimental Allergy, Nov 1, 1995

Thorax, 1999

Thorax, 2003

New England Journal of Medicine, 2002

The Journal of Immunology, 2001

Journal of Experimental Medicine, 1994

Journal of Allergy and Clinical Immunology, 2002

Journal of Allergy and Clinical Immunology, 2005

Journal of Allergy and Clinical Immunology, 2002