Dominique Bullens

Bio: Dominique Bullens is an academic researcher from Katholieke Universiteit Leuven. The author has contributed to research in topics: T cell & Asthma. The author has an hindex of 36, co-authored 118 publications receiving 3950 citations. Previous affiliations of Dominique Bullens include Université catholique de Louvain & Catholic University of Leuven.

IL-17 mRNA in sputum of asthmatic patients: linking T cell driven inflammation and granulocytic influx?

Abstract: The role of Th2 cells (producing interleukin (IL-)4, IL-5 and IL-13) in allergic asthma is well-defined. A distinct proinflammatory T cell lineage has recently been identified, called Th17 cells, producing IL-17A, a cytokine that induces CXCL8 (IL-8) and recruits neutrophils. Neutrophilic infiltration in the airways is prominent in severe asthma exacerbations and may contribute to airway gland hypersecretion, bronchial hyper-reactivity and airway wall remodelling in asthma. to study the production of IL-17 in asthmatic airways at the mRNA level, and to correlate this with IL-8 mRNA, neutrophilic inflammation and asthma severity. We obtained airway cells by sputum induction from healthy individuals (n = 15) and from asthmatic patients (n = 39). Neutrophils were counted on cytospins and IL-17A and IL-8 mRNA expression was quantified by real-time RT-PCR (n = 11 controls and 33 asthmatics). Sputum IL-17A and IL-8 mRNA levels are significantly elevated in asthma patients compared to healthy controls. IL-17 mRNA levels are significantly correlated with CD3γ mRNA levels in asthmatic patients and mRNA levels of IL-17A and IL-8 correlated with each other and with sputum neutrophil counts. High sputum IL-8 and IL-17A mRNA levels were also found in moderate-to-severe (persistent) asthmatics on inhaled steroid treatment. The data suggest that Th17 cell infiltration in asthmatic airways links T cell activity with neutrophilic inflammation in asthma.

Impaired barrier function in patients with house dust mite-induced allergic rhinitis is accompanied by decreased occludin and zonula occludens-1 expression.

Abstract: Background Tight junction (TJ) defects have recently been associated with asthma and chronic rhinosinusitis. The expression, function, and regulation of nasal epithelial TJs remain unknown in patients with allergic rhinitis (AR). Objective We investigated the expression, function, and regulation of TJs in the nasal epithelium of patients with house dust mite (HDM)–induced AR and in an HDM-induced murine model of allergic airway disease. Methods Air-liquid interface cultures of primary nasal epithelial cells of control subjects and patients with HDM-induced AR were used for measuring transepithelial resistance and passage to fluorescein isothiocyanate–dextran 4 kDa (FD4). Ex vivo transtissue resistance and FD4 permeability of nasal mucosal explants were measured. TJ expression was evaluated by using real-time quantitative PCR and immunofluorescence. In addition, the effects of IL-4, IFN-γ, and fluticasone propionate (FP) on nasal epithelial cells were investigated in vitro . An HDM murine model was used to study the effects of allergic inflammation and FP treatment on transmucosal passage of FD4 in vivo . Results A decreased resistance in vitro and ex vivo was found in patients with HDM-induced AR, with increased FD4 permeability and reduced occludin and zonula occludens-1 expression. AR symptoms correlated inversely with resistance in patients with HDM-induced AR. In vitro IL-4 decreased transepithelial resistance and increased FD4 permeability, whereas IFN-γ had no effect. FP prevented IL-4–induced barrier dysfunction in vitro . In an HDM murine model FP prevented the allergen-induced increased mucosal permeability. Conclusion We found impaired nasal epithelial barrier function in patients with HDM-induced AR, with lower occludin and zonula occludens-1 expression. IL-4 disrupted epithelial integrity in vitro , and FP restored barrier function. Better understanding of nasal barrier regulation might lead to a better understanding and treatment of AR.

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

Abstract: 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)-γ) 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-γ 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-γ 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 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-γ indicate asthma severity. The technique is a promising tool for use in further studies of asthma severity and disease activity.

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

Abstract: 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.

Defective CD4+CD25+ regulatory T cell functioning in collagen-induced arthritis: an important factor in pathogenesis, counter-regulated by endogenous IFN-γ

Abstract: Mice with a deficiency in IFN-γ or IFN-γ receptor (IFN-γR) are more susceptible to collagen-induced arthritis (CIA), an experimental autoimmune disease that relies on the use of complete Freund's adjuvant (CFA). Here we report that the heightened susceptibility of IFN-γR knock-out (KO) mice is associated with a functional impairment of CD4+CD25+ Treg cells. Treatment of wild-type mice with depleting anti-CD25 antibody after CFA-assisted immunisation with collagen type II (CII) significantly accelerated the onset of arthritis and increased the severity of CIA. This is an indication of a role of Treg cells in the effector phase of CIA. IFN-γR deficiency did not affect the number of CD4+CD25+ T cells in the central and peripheral lymphoid tissues. In addition, CD4+CD25+ T cells isolated from naive IFN-γR KO mice had a normal potential to suppress T cell proliferation in vitro. However, after immunisation with CII in CFA, the suppressive activity of CD4+CD25+ T cells became significantly more impaired in IFN-γR-deficient mice. Moreover, expression of the mRNA for Foxp3, a highly specific marker for Treg cells, was lower. We further demonstrated that the effect of endogenous IFN-γ, which accounts for more suppressive activity in wild-type mice, concerns both Treg cells and accessory cells. Our results demonstrate that the decrease in Treg cell activity in CIA is counter-regulated by endogenous IFN-γ.

European Position Paper on Rhinosinusitis and Nasal Polyps 2020

Abstract: The European Position Paper on Rhinosinusitis and Nasal Polyps 2020 is the update of similar evidence based position papers published in 2005 and 2007 and 2012. The core objective of the EPOS2020 guideline is to provide revised, up-to-date and clear evidence-based recommendations and integrated care pathways in ARS and CRS. EPOS2020 provides an update on the literature published and studies undertaken in the eight years since the EPOS2012 position paper was published and addresses areas not extensively covered in EPOS2012 such as paediatric CRS and sinus surgery. EPOS2020 also involves new stakeholders, including pharmacists and patients, and addresses new target users who have become more involved in the management and treatment of rhinosinusitis since the publication of the last EPOS document, including pharmacists, nurses, specialised care givers and indeed patients themselves, who employ increasing self-management of their condition using over the counter treatments. The document provides suggestions for future research in this area and offers updated guidance for definitions and outcome measurements in research in different settings. EPOS2020 contains chapters on definitions and classification where we have defined a large number of terms and indicated preferred terms. A new classification of CRS into primary and secondary CRS and further division into localized and diffuse disease, based on anatomic distribution is proposed. There are extensive chapters on epidemiology and predisposing factors, inflammatory mechanisms, (differential) diagnosis of facial pain, allergic rhinitis, genetics, cystic fibrosis, aspirin exacerbated respiratory disease, immunodeficiencies, allergic fungal rhinosinusitis and the relationship between upper and lower airways. The chapters on paediatric acute and chronic rhinosinusitis are totally rewritten. All available evidence for the management of acute rhinosinusitis and chronic rhinosinusitis with or without nasal polyps in adults and children is systematically reviewed and integrated care pathways based on the evidence are proposed. Despite considerable increases in the amount of quality publications in recent years, a large number of practical clinical questions remain. It was agreed that the best way to address these was to conduct a Delphi exercise . The results have been integrated into the respective sections. Last but not least, advice for patients and pharmacists and a new list of research needs are included. The full document can be downloaded for free on the website of this journal: http://www.rhinologyjournal.com.

Immunology of asthma and chronic obstructive pulmonary disease

Abstract: Asthma and chronic obstructive pulmonary disease (COPD) are both obstructive airway diseases that involve chronic inflammation of the respiratory tract, but the type of inflammation is markedly different between these diseases, with different patterns of inflammatory cells and mediators being involved As described in this Review, these inflammatory profiles are largely determined by the involvement of different immune cells, which orchestrate the recruitment and activation of inflammatory cells that drive the distinct patterns of structural changes in these diseases However, it is now becoming clear that the distinction between these diseases becomes blurred in patients with severe asthma, in asthmatic subjects who smoke and during acute exacerbations This has important implications for the development of new therapies

Meta-analysis identifies 29 additional ulcerative colitis risk loci, increasing the number of confirmed associations to 47.

Abstract: Genome-wide association studies and candidate gene studies in ulcerative colitis have identified 18 susceptibility loci. We conducted a meta-analysis of six ulcerative colitis genome-wide association study datasets, comprising 6,687 cases and 19,718 controls, and followed up the top association signals in 9,628 cases and 12,917 controls. We identified 29 additional risk loci (P < 5 × 10(-8)), increasing the number of ulcerative colitis-associated loci to 47. After annotating associated regions using GRAIL, expression quantitative trait loci data and correlations with non-synonymous SNPs, we identified many candidate genes that provide potentially important insights into disease pathogenesis, including IL1R2, IL8RA-IL8RB, IL7R, IL12B, DAP, PRDM1, JAK2, IRF5, GNA12 and LSP1. The total number of confirmed inflammatory bowel disease risk loci is now 99, including a minimum of 28 shared association signals between Crohn's disease and ulcerative colitis.

Psychometric validity of the 22-item Sinonasal Outcome Test.

Abstract: Objectives: We set out to determine the psychometric validation of a disease-specific health related quality of life instrument for use in chronic rhinosinusitis, the 22 item Sinonasal Outcome Test (SNOT-22), a modification of a pre-existing instrument, the SNOT-20. Design, setting and participants: The National Comparative Audit of Surgery for Nasal Polyposis and Chronic Rhinosinusitis was a prospective cohort study collecting data on 3128 adult patients undergoing sinonasal surgery in 87 NHS hospitals in England and Wales. Data were collected preoperatively and at 3 months after surgery, and analysed to determine validity of the SNOT-22. Test–retest reliability was assessed in a separate cohort of patients in a single centre. Main outcome measures: The SNOT-22, a derivative of the SNOT-20 was the main outcome measure. Patients were also asked to report whether they felt better, the same or worse following surgery. To evaluate the SNOT-22, the internal consistency, responsiveness, known group differences and validity were analysed. Results: Preoperative SNOT-22 scores were completed by 2803 patients. 3-month postoperative SNOT-22 scores were available for 2284 patients of all patients who completed a preoperative form (81.5% response rate). The Cronbach’s alpha scores for the SNOT-22 were 0.91 indicating high internal consistency. The test–retest reliability coefficient was 0.93, indicating high reliability of repeated measures. The SNOT-22 was able to discriminate between patients known to suffer with chronic rhinosinusitis and a group of healthy controls (P < 0.0001, t = 85.3). It was also able to identify statistically significant differences in sub-groups of patients with chronic rhinosinusitis. There was a statistically significant (P < 0.0001, t = 39.94) decrease in patient reported SNOT-22 scores at 3 months. At 3 months the overall effect size in all patients was 0.81, which is considered large. We found the minimally important difference that is the smallest change in SNOT-22 score that can be detected by a patient, to be 8.9 points. Conclusions: We have found the SNOT-22 to be valid and easy to use. It can be used to facilitate routine clinical practice to highlight the impact of chronic rhinosinusitis on the patient’s quality of life, and may also be used to measure the outcome of surgical intervention. The minimally important difference allows us to interpret scores in a clinical context, and may help to improve patient selection for surgery.

Targeting IL-17 and TH17 cells in chronic inflammation.

Abstract: The key role of interleukin-17 (IL-17) and T helper 17 (T(H)17) cells in tissue inflammation, autoimmunity and host defence led to the experimental targeting of these molecules in mouse models of diseases as well as in clinical settings. Moreover, the demonstration that IL-17 and T(H)17 cells contribute to local and systemic aspects of disease pathogenesis, as well as the finding that the IL-17-T(H)17 cell pathway is regulated by IL-23, prompted the identification of inhibitors. These inhibitors include biotechnology products that target IL-23 as well as the leading member of the IL-17 family, IL-17A, and one of its receptors, IL-17 receptor A. Several clinical trials of these inhibitors are underway, and positive results have been obtained in psoriasis, rheumatoid arthritis and ankylosing spondylitis. This Review focuses on the current knowledge of the IL-17-T(H)17 cell pathway to better understand the positive as well as potential negative consequences of targeting them.