Derek Chu

McMaster University | McMaster · Department of Medicine

Background Allergen exposure at lung and gut mucosae can lead to aberrant TH2 immunity and allergic disease. The epithelium-associated cytokines thymic stromal lymphopoietin (TSLP), IL-25, and IL-33 are suggested to be important for the initiation of these responses. Objective We sought to investigate the contributions of TSLP, IL-25, and IL-33 in...

Determining the cellular and molecular phenotypes of inflammation in asthma can identify patient populations that may best benefit from targeted therapies. Although elevated IL-6 and polymorphisms in IL-6 signalling are associated with lung dysfunction in asthma, it remains unknown if elevated IL-6 levels are associated with a specific cellular inf...

Background A number of food allergies (e.g. fish, shellfish, nuts) are lifelong, without any disease-transforming therapies and unclear in their underlying immunology. Clinical manifestations of food allergy are largely mediated by IgE. Although persistent IgE titres have conventionally been attributed to long-lived IgE+ plasma cells (PCs), this h...

Background: Supplemental oxygen is often administered liberally to acutely ill adults, but the credibility of the evidence for this practice is unclear. We systematically reviewed the efficacy and safety of liberal versus conservative oxygen therapy in acutely ill adults. Methods: In the Improving Oxygen Therapy in Acute-illness (IOTA) systematic r...

Background: Oral immunotherapy is an emerging experimental treatment for peanut allergy, but its benefits and harms are unclear. We systematically reviewed the efficacy and safety of oral immunotherapy versus allergen avoidance or placebo (no oral immunotherapy) for peanut allergy. Methods: In the Peanut Allergen immunotherapy, Clarifying the Evide...

Objective This article describes GRADE guidance for assessing imprecision when rating the certainty of the evidence from network meta-analysis. Study design and setting A project group within the GRADE working group conducted iterative discussions, computer simulations, and presentations at GRADE working group meetings to produce and obtain approv...

Food allergies are antigen-driven diseases that can lead to IgE-mediated reactions of immediate hypersensitivity (eg. anaphylaxis triggered by a single food), or non-IgE reactions of delayed hypersensitivity such as eosinophilic esophagitis (EoE; eg. inability to eat multiple foods manifesting as abdominal pain, choking, dysphagia, vomiting, reflux...

Network meta‐analyses (NMAs) simultaneously estimate effects of multiple possible treatment options for a given clinical presentation. For allergists to benefit optimally from NMAs they must understand the process and be able to interpret the results. Through a worked example published in Pediatric Allergy and Immunology, we summarize how to identi...

Concerns for anaphylaxis may hamper SARS-CoV-2 immunization efforts. We convened a multi-disciplinary group of international experts in anaphylaxis comprised of allergy, infectious disease, emergency medicine, and front-line clinicians to systematically develop recommendations regarding SARS-CoV-2 vaccine immediate allergic reactions. Medline, EMBA...

Allergen immunotherapy (AIT), the gradually increasing repeated administration of high doses of allergens to allergic patients, offers the potential for immune tolerance against reactions to the natural exposures to specific allergens. AIT may lead to the long-lasting remission of allergic symptoms and is the only disease-modifying intervention in...

Background Observational comparative effectiveness studies in allergen immunotherapy (AIT) represent an important evidence source answering research questions that can be challenging to obtain from randomized controlled trials (RCTs), such as long-term benefits of AIT, the effects on asthma prevention and the onset of new allergen sensitizations. H...

Importance The benefits and harms of adding long-acting muscarinic antagonists (LAMAs) to inhaled corticosteroids (ICS) and long-acting β2-agonists (LABAs) for moderate to severe asthma remain unclear. Objective To systematically synthesize the outcomes and adverse events associated with triple therapy (ICS, LABA, and LAMA) vs dual therapy (ICS pl...

Food allergy management in child care centers and schools is a controversial topic, for which evidence-based guidance is needed. Following the Grading of Recommendations Assessment, Development, and Evaluation approach, we conducted systematic literature reviews of the anticipated health effects of selected interventions for managing food allergy i...

Objective: To determine and compare the effects of drug prophylaxis on SARS-CoV-2 infection and covid-19. Design: Living systematic review and network meta-analysis. Data sources: World Health Organization covid-19 database, a comprehensive multilingual source of global covid-19 literature to 25 March 2021, and six additional Chinese databases...

Older adults, especially men and/or those with diabetes, hypertension and/or obesity, are prone to severe COVID‐19. In some countries, older adults, particularly those residing in nursing homes, have been prioritised to receive COVID‐19 vaccines due to high risk of death. In very rare instances,the COVID‐19 vaccines can induce anaphylaxis, and the...

Background Although there are many asymptomatic patients, one of the problems of COVID‐19 is early recognition of the disease. COVID‐19 symptoms are polymorphic and may include upper respiratory symptoms. However, COVID‐19 symptoms may be mistaken withthe common cold or allergic rhinitis. An ARIA‐EAACI study group attempted to differentiate upper r...

Background Data are sparse regarding clinical characteristics and management of fruit-induced anaphylaxis Objective To assess clinical characteristics and management of patients with fruit-induced anaphylaxis and determine factors associated with severe reactions and epinephrine use. Methods Over 9 years, children and adults presenting with anaph...

Objective To determine and compare the effects of drug prophylaxis on severe acute respiratory syndrome coronavirus virus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (covid-19). Design Living systematic review and network meta-analysis. Data sources WHO covid-19 database, a comprehensive multilingual source of global covid-19 literature t...

Although there is a considerable body of knowledge about allergen immunotherapy (AIT), there is a lack of data on the reliability of real‐world evidence (RWE) in AIT and consequently, a lack of information on how AIT effectively works in real life. To address the current unmet need for an appraisal of the quality of RWE in AIT, the European Academy...

Although there is a considerable body of knowledge about allergen immunotherapy (AIT), there is a lack of data on the reliability of real-world evidence (RWE) in AIT and consequently, a lack of information on how AIT effectively works in real life. To address the current unmet need for an appraisal of the quality of RWE in AIT, the European Academy...

The rapidly unfolding Coronavirus Disease of 2019 (COVID-19) pandemic and an ever-increasing volume of relevant literature presents considerable strain for decision makers. Those decision makers are interested in information not only about benefits and harms of interventions but also contextual information such as people’s values and preferences, c...

Background: IgE production against innocuous food antigens can result in anaphylaxis, a severe life-threatening consequence of allergic reactions. The maintenance of IgE immunity is primarily facilitated by IgG + memory B cells (MBCs), as IgE + MBCs and IgE + plasma cells are extremely scarce and short-lived, respectively. Objective:To investigate...

Introduction In an attempt to improve outcomes for patients with coronavirus disease 19 (COVID-19), several drugs, such as remdesivir, hydroxychloroquine (with or without azithromycin), and lopinavir/ritonavir, have been evaluated for treatment. While much attention focuses on potential benefits of these drugs, this must be weighed against their ad...

Objective: To propose an approach for developing trustworthy recommendations as part of urgent responses (1-2 weeks) in the clinical, public health, and health systems fields. Study design and setting: We conducted a review of the literature, outlined a draft approach, refined the concept through iterative discussions, a workshop by the GRADE Rapi...

Background: It is not established whether the risk of anaphylaxis induced by peanuts or tree nuts in children increases at specific times of the year. We aimed to evaluate the risk of peanut-and tree-nut-induced anaphylaxis during certain cultural holidays in Canadian children. Methods: We collected data on confirmed pediatric cases of anaphylax...

Given the burden of disease and the consequences of a diagnosis of peanut allergy, it is important that peanut allergy be accurately diagnosed so that an appropriate treatment plan can be developed. However, a test that indicates there is peanut sensitization present (e.g., a “positive” test) is not always associated with clinical reactivity. This...

Objective To compare the effects of treatments for coronavirus disease 2019 (covid-19). Design Living systematic review and network meta-analysis. Data sources US Centers for Disease Control and Prevention COVID-19 Research Articles Downloadable Database, which includes 25 electronic databases and six additional Chinese databases to 20 July 2020....

Digital anamorphosis is used to define a distorted image of health and care that may be viewed correctly using digital tools and strategies. MASK digital anamorphosis represents the process used by MASK to develop the digital transformation of health and care in rhinitis.It strengthens the ARIA change management strategy in the prevention and manag...

Severe asthma imposes a significant burden on patients, families and healthcare systems. Management is difficult, due to disease heterogeneity, comorbidities, complexity in care pathways and differences between national or regional healthcare systems. Better understanding of the mechanisms has enabled a stratified approach to the management of seve...

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and is spread person-to-person through close contact. We aimed to investigate the effects of physical distance, face masks, and eye protection on virus transmission in health-care and non-health-care (eg, community) settings. Methods We did a systematic review...

Background: Mechanical ventilation is used to treat respiratory failure in coronavirus disease 2019 (COVID-19). Purpose: To review multiple streams of evidence regarding the benefits and harms of ventilation techniques for coronavirus infections, including that causing COVID-19. (PROSPERO registration: CRD42020178187). Data sources: 21 standar...

Introduction Proper strategies to minimise the risk of infection in individuals handling the bodies of deceased persons infected with 2019 novel coronavirus (2019-nCoV) are urgently needed. The objective of this study was to systematically review the literature to scope and assess the effects of specific strategies for the management of the bodies....

Introduction: There are few large-scale studies assessing the true risk of epinephrine use during anaphylaxis in adults. We aimed to assess the demographics, clinical characteristics, and secondary effects of epinephrine treatment and to determine factors associated with major and minor secondary effects associated with epinephrine use among adults...

IgE production against innocuous antigens can lead to life-threatening reactions such as anaphylaxis. While IgE levels drastically decline with strict allergen avoidance, the ability to regenerate IgE can persist for a lifetime, as is the case for peanut allergy. The mechanism by which IgE regenerates remains unresolved. A novel culture system and...

Objective To review GRADE methodology and discuss the clinical application of conditional recommendations in clinical guidelines, specifically in the context of anaphylaxis. Data Sources Articles describing GRADE, evidence synthesis, evidence to recommendation frameworks, and shared decision making were used to discuss conditional recommendations...

Eosinophils have emerged as multifaceted cells that contribute to tissue homeostasis. However, the impact of the microbiota on their frequency and function at mucosal sites remains unclear. Here, we investigated the role of the microbiota in the regulation of enteric eosinophils. We found that small intestinal (SI) eosinophilia was significantly gr...

Anaphylaxis is an acute systemic allergic reaction that can be life threatening. In adults, the most common causes of anaphylaxis are foods, drugs, and insect stings. This article reviews the definition, classification, evaluation, differential diagnosis, prognosis, complications, and management of anaphylaxis. Tailored for internists, the article...

Aims Mobile Airways Sentinel NetworK (MASK) belongs to the Fondation Partenariale MACVIA-LR of Montpellier, France and aims to provide an active and healthy life to rhinitis sufferers and to those with asthma multimorbidity across the life cycle, whatever their gender or socio-economic status, in order to reduce health and social inequities incurre...

Background: In all societies, the burden and cost of allergic and chronic respiratory diseases are increasing rapidly. Most economies are struggling to deliver modern health care effectively. There is a need to support the transformation of the health care system into integrated care with organizational health literacy. Main body: As an example...

The selection of pharmacotherapy for patients with allergic rhinitis aims to control the disease and depends on many factors. Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines have considerably improved the treatment of allergic rhinitis. However, there is an increasing trend toward use of real-world evidence to i...

Background Aspirin desensitization is increasingly recommended for the treatment of aspirin‐exacerbated respiratory disease (AERD). The objective of this study is to systematically review the efficacy and safety of aspirin desensitization in patients with AERD. Methods We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Tria...

Allergen immunotherapy (AIT) is a proven therapeutic option for the treatment of allergic rhinitis and/or asthma. Many guidelines or national practice guidelines have been produced but the evidence‐based method varies, many are complex and none propose care pathways. This paper reviews care pathways for AIT using strict criteria and provides simple...

A 52-year-old man presented with chronic urticaria that was refractory to standard chronic spontaneous urticaria (CSU) treatment. Over time, he developed systemic symptoms including fatigue, weight loss, arthralgia and bone pain. His laboratory investigations also became significant for microcytic anaemia, neutrophilia and elevated C reactive prote...

Eosinophils have emerged as multifaceted cells that contribute to tissue homeostasis. However, the factors that control their frequency and function at mucosal sites remain unclear. Here, we investigated the role of the microbiota in regulating enteric eosinophils. We found that small intestinal (SI) eosinophilia was significantly greater in germ-f...

What is the best way to use oxygen therapy for patients with an acute medical illness? A systematic review published in the Lancet in April 2018 found that supplemental oxygen in inpatients with normal oxygen saturation increases mortality. Its authors concluded that oxygen should be administered conservatively, but they did not make specific recom...

Background The generation of IgE‐mediated food allergy in humans is silent, and only diagnosed upon manifestation of clinical symptoms. While experimental models have been used to investigate some mechanisms of allergic sensitization, the generation of humoral immunity and memory remain to be elucidated. Here, we defined the evolution of allergen‐s...

In contrast with Th1 immune responses against pathogenic viruses and bacteria, the incipient events that generate Th2 responses remain less understood. One difficulty in the identification of universal operating principles stems from the diversity of entities against which cellular and molecular Th2 responses are produced. Such responses are launch...

In contrast to Th1 immune responses against pathogenic viruses and bacteria, the incipient events that generate Th2 responses remain less understood. Part of the difficulty in identifying universal operating principles stems from the diversity of entities against which cellular and molecular Th2 responses are produced. Indeed, such responses are la...

Th2 humoral immunity (IgE) is protective against venoms and parasites but detrimental when mounted against innocuous proteins such as food allergens. The generation of IgE immunity toward harmless allergens is initiated at the body barriers (i.e. mucosae and skin) where the allergen and the immune system first meet. Epithelial cytokines (such as TS...

Background: Patients with essential thrombocythemia (ET) are at high risk for both thrombosis and hemorrhage. Purpose: To evaluate the risks and benefits of antithrombotic therapy in adults with ET. Data sources: Multiple databases, including MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, through 4 March 2017. Study...

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Clinical and experimental studies have shown that estradiol (E2) confers protection against HIV and other sexually transmitted infections. Here, we investigated the underlying mechanism. Better protection in E2-treated mice, immunized against genital HSV-2, coincided with earlier recruitment and higher proportions of Th1 and Th17 effector cells in...

Background Food allergy, in particular peanut allergy, is a growing concern in Western countries. The prevalence of allergy to peanut, which currently stands at 1.4%, has nearly tripled between 1997 to 2008. Allergic sensitization is a particularly difficult process to study as it is clinically silent.Objective We sought to identify key pathways an...

Cigarette smoke has a broad impact on the mucosal environment with the ability to alter host defense mechanisms. Within the context of a bacterial infection, this altered host response is often accompanied by exacerbated cellular inflammation, characterized by increased neutrophilia. The current study investigated the mechanisms of neutrophil recru...

Eosinophils natively inhabit the small intestine, but a functional role for them there has remained elusive. Here, we show that eosinophil-deficient mice were protected from induction of Th2-mediated peanut food allergy and anaphylaxis, and Th2 priming was restored by reconstitution with il4+/+ or il4−/− eosinophils. Eosinophils controlled CD103+ d...

Intestinal T helper type 2 (Th2) immunity in food allergy results in IgG1 and IgE production, and antigen re-exposure elicits responses such as anaphylaxis and eosinophilic inflammation. Although interleukin-4 (IL-4) is critically required for allergic sensitization, the source and control of IL-4 during the initiation of Th2 immunity in vivo remai...

Allergic asthma is a chronic immune-inflammatory disease of the airways. Despite aeroallergen exposure being universal, allergic asthma affects only a fraction of individuals. This is likely related, at least in part, to the extent of allergen exposure. Regarding house dust mite (HDM), we previously identified the threshold required to elicit aller...

Microbiota regulates eosinophils in the small intestine R. Jimenez-Saiz1, T. Walker1, M.E. Gordon1, W.S. Ahmed1, B. Dale1, T.S. Mandur1, J. Kong1, D.K. Chu1, R. Kolbeck2, A.A. Humbles2, E.F. Verdu3, M. Jordana1. 1McMaster Immunology Research Centre (MIRC), 3 Farcombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON,...

The origins of allergic asthma, particularly in infancy, remain obscure. Respiratory viral infections and allergen sensitization in early life have been associated with asthma in young children. However, a causal link has not been established. We investigated whether an influenza A infection in early life alters immune responses to house dust mite...

Food-induced anaphylaxis is often a severe allergic reaction characterized by multiorgan dysfunction and a potentially fatal outcome. We sought to investigate the relative contribution of immunoglobulin-dependent effector pathways to anaphylactic responses to food (ie, peanut). Wild-type and various mutant mice were sensitized with peanut protein a...