MeDALL (Mechanisms of the Development of ALLergy): an integrated approach from phenotypes to systems medicine

Fungi: the neglected allergenic sources

Allergic diseases are considered the epidemics of the twentieth century estimated to affect more than 30% of the population in industrialized countries with a still increasing incidence. During the past two decades, the application of molecular biology allowed cloning, production and characterization of hundreds of recombinant allergens. In turn, knowledge about molecular, chemical and biologically relevant allergens contributed to increase our understanding of the mechanisms underlying IgE-mediated type I hypersensitivity reactions. It has been largely demonstrated that fungi are potent sources of allergenic molecules covering a vast variety of molecular structures including enzymes, toxins, cell wall components and phylogenetically highly conserved cross-reactive proteins. Despite the large knowledge accumulated and the compelling evidence for an involvement of fungal allergens in the pathophysiology of allergic diseases, fungi as a prominent source of allergens are still largely neglected in basic research as well as in clinical practice. This review aims to highlight the impact of fungal allergens with focus on asthma and atopic dermatitis.

The human IgE repertoire

IgE is a key mediator in allergic diseases. However, in strong contrast to other antibody isotypes, many details of the composition of the human IgE repertoire are poorly defined. The low levels of human IgE in the circulation and the rarity of IgE-producing B cells are important reasons for this lack of knowledge. In this review, we summarize the current knowledge on these repertoires both in terms of their complexity and activity, i.e. knowledge which despite the difficulties encountered when studying the molecular details of human IgE has been acquired in recent years. We also take a look at likely future developments, for instance through improvements in sequencing technology and methodology that allow the isolation of additional allergen-specific human antibodies mimicking IgE, as this certainly will support our understanding of human IgE in the context of human disease in the years to come.

Communication of results and disclosure of incidental findings in longitudinal paediatric research

BACKGROUND

Communicating results to research participants is an issue frequently discussed in terms of ethics. It has specific features when involving large-scale paediatric cohorts. High-throughput biological explorations reveal also incidental findings of medical relevance. This work analyses existing frameworks for managing such issues and proposes a policy grounded in the experience acquired in the FP7 EU project MeDALL-Mechanisms of the Development of ALLergy.

METHODS

A bibliographical analysis was performed using law, ethics and academic documentation. Empirical data were acquired through informed consent forms from 9 of the 13 cohorts used in MeDALL and from replies to a general questionnaire (n = 10) on ethical issues sent to consortium members. Group discussions and expert consultations were conducted during project meetings.

RESULTS

The notions of research results and incidental findings remain ambiguous as no agreed definition exists. The most appropriate terms are communication of results and disclosure of incidental findings. No legal norm and no specific guidance govern these issues in paediatric research at European level. Relevant policies depend on decisions in each cohort or project. The policy proposed states that these issues should be discussed during the informed consent process, with due attention to involvement of children, and a balance of interests between children, parents and society. A moral duty for researchers to communicate such information only applies if certain medical and social criteria are met.

CONCLUSIONS

As there is no consensus within European Birth cohorts how to deal with results and incidental findings, we propose a general policy.

Impact of early diagnosis and control of chronic respiratory diseases on active and healthy ageing. A debate at the European Union Parliament

A debate at the European Union Parliament was held on 13 November 2012 on the Impact of early diagnosis and control of chronic respiratory diseases on Active and Healthy Ageing (AHA). The debate was held under the auspices of the Cyprus Presidency of the European Union (2012) and represents a follow-up of the priorities of the Polish Presidency of the European Union (2011). It highlighted the importance of early life events on the occurrence of chronic respiratory diseases later in life and their impact on active and healthy ageing. Epidemiologic evidence was followed by actions that should be taken to prevent and manage chronic respiratory diseases in children. The debate ended by practical, feasible and achievable projects, demonstrating the strength of the political action in the field. Three projects will be initiated from this debate: The first will be a meeting sponsored by the Région Languedoc-Roussillon on the developmental origins of chronic diseases and ageing: from research to policies and value creation. The second project is being led by the WHO Collaborating Centre for Asthma and Rhinitis: Prevention of Asthma, Prevention of Allergy (PAPA). The third project is the GA(2)LEN sentinel network.

Effects of persistent organic pollutants on the developing respiratory and immune systems: a systematic review

BACKGROUND

Disruption of developing immune and respiratory systems by early-life exposure to persistent organic pollutants (POPs) could result into reduced capacity to fight infections and increased risk to develop allergic manifestations later in life.

OBJECTIVES

To systematically review the epidemiologic literature on the adverse effects of early-life exposure to POPs on respiratory health, allergy and the immune system in infancy, childhood and adolescence.

METHODS

Based on published guidelines for systematic reviews, two independent researchers searched for published articles in MEDLINE and SCOPUS using defined keywords on POPs and respiratory health, immune function and allergy. Study eligibility criteria were defined to select the articles.

RESULTS

This review of 41 studies finds limited evidence for prenatal exposure to DDE, PCBs and dioxins and risk of respiratory infections. Evidence was limited also for postnatal exposure to PCBs, specifically ndl-PCBs, and reduced immune response after vaccination in childhood. The review indicates lack of association between postnatal exposure to PCBs/ndl-PCBs and risk of asthma-related symptoms. For the other exposure-outcome associations reviewed evidence was inadequate.

DISCUSSION AND CONCLUSION

Current epidemiological evidence suggests that early-life exposure to POPs can adversely influence immune and respiratory systems development. Heterogeneity between studies in exposure and outcome assessment and the small number of studies for any given exposure-outcome relationship currently make comparisons difficult and meta-analyses impossible. Also, mechanisms remain largely unexplored. Recommendations for significantly improving our understanding thus include harmonization of exposure and outcome assessment between studies, conduct of larger studies, long-term assessment of respiratory infections and asthma symptoms in order to identify critical periods of susceptibility, integration of the potential immunotoxic mechanisms of POPs, and use of new statistical tools to detangle the role of multiple exposures on multiple outcomes.

Pooling birth cohorts in allergy and asthma: European Union-funded initiatives - a MeDALL, CHICOS, ENRIECO, and GA²LEN joint paper

Long-term birth cohort studies are essential to understanding the life course and childhood predictors of allergy and the complex interplay between genes and the environment (including lifestyle and socioeconomic determinants). Over 100 cohorts focusing on asthma and allergy have been initiated in the world over the past 30 years. Since 2004, several research initiatives funded under the EU Framework Program for Research and Technological Development FP6-FP7 have attempted to identify, compare, and evaluate pooling data from existing European birth cohorts (GA(2)LEN: Global Allergy and European Network, FP6; ENRIECO: Environmental Health Risks in European Birth Cohorts, FP7; CHICOS: Developing a Child Cohort Research Strategy for Europe, FP7; MeDALL: Mechanisms of the Development of ALLergy, FP7). However, there is a general lack of knowledge about these initiatives and their potentials. The aim of this paper is to review current and past EU-funded projects in order to make a summary of their goals and achievements and to suggest future research needs of these European birth cohort networks.

Allergic Rhinitis and its Impact on Asthma (ARIA): achievements in 10 years and future needs

Allergic rhinitis (AR) and asthma represent global health problems for all age groups. Asthma and rhinitis frequently coexist in the same subjects. Allergic Rhinitis and its Impact on Asthma (ARIA) was initiated during a World Health Organization workshop in 1999 (published in 2001). ARIA has reclassified AR as mild/moderate-severe and intermittent/persistent. This classification closely reflects patients' needs and underlines the close relationship between rhinitis and asthma. Patients, clinicians, and other health care professionals are confronted with various treatment choices for the management of AR. This contributes to considerable variation in clinical practice, and worldwide, patients, clinicians, and other health care professionals are faced with uncertainty about the relative merits and downsides of the various treatment options. In its 2010 Revision, ARIA developed clinical practice guidelines for the management of AR and asthma comorbidities based on the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system. ARIA is disseminated and implemented in more than 50 countries of the world. Ten years after the publication of the ARIA World Health Organization workshop report, it is important to make a summary of its achievements and identify the still unmet clinical, research, and implementation needs to strengthen the 2011 European Union Priority on allergy and asthma in children.

The Finnish Allergy Programme 2008-2018 - scientific rationale and practical implementation

There are no nationwide, comprehensive public health programmes on allergic disorders with set goals and systematic follow-up. The Finnish initiative is based on the idea that the so called allergy epidemic in modern, urban societies is caused by inadequately developed or broken tolerance. The immune system is not trained to make the difference between danger and non-danger (allergy) or the difference between self and non-self (autoimmune diseases). The immune dysfunction leads to inappropriate inflammatory responses and clinical symptoms. The 10-year implementation programme is aimed to reduce burden of allergies both at the individual and societal levels. This is done by increasing both immunological and psychological tolerance and changing attitudes to support health instead of medicalising common and mild allergy symptoms. Severe forms of allergy are in special focus, e.g. asthma attacks are prevented proactively by improving disease control with the help of guided self-management. Networking of allergy experts with primary care doctors and nurses as well with pharmacists is the key for effective implementation. Non-governmental organizations have started a campaign to increase allergy awareness and knowledge among patients and general public. It is time to act, when allergic individuals are becoming a majority of Western populations and their numbers are in rapid increase worldwide. The first results of the Finnish Programme indicate that allergy burden can be reduced with relatively simple means.

Risk factors and characteristics of respiratory and allergic phenotypes in early childhood

BACKGROUND

Unsupervised approaches can be used to analyze complex respiratory and allergic disorders.

OBJECTIVE

We investigated the respiratory and allergic phenotypes of children followed in the Pollution and Asthma Risk: An Infant Study (PARIS) birth cohort.

METHODS

Information on respiratory and allergic disorders, medical visits, and medications was collected during medical examinations of children at 18 months of age; biomarker data were also collected (total and allergen-specific IgE levels and eosinophilia). Phenotypes were determined by using latent class analysis. Associated risk factors were determined based on answers to questionnaires about environmental exposures.

RESULTS

Apart from a reference group, which had a low prevalence of respiratory symptoms or allergies (n=1271 [69.4%]), 3 phenotypes were identified. On the basis of clinical signs of severity and use of health care resources, we identified a mild phenotype (n=306 [16.7%]) characterized by occasional mild wheeze and 2 severe phenotypes separated by atopic status. The atopic severe phenotype (n=59 [3.2%]) included 49 (83%) children with wheezing and was characterized by a high prevalence of atopy (61% with allergenic sensitization) and atopic dermatitis (78%). In contrast, atopy was rare among children with the nonatopic severe phenotype (n=195 [11%]); this group included 88% of the children with recurrent wheezing. Risk factors for respiratory disease included parental history of asthma, male sex, siblings, day care attendance, exposure to tobacco smoke or molds, indoor renovations, and being overweight, although these factors did not have similar affects on risk for all phenotypes.

CONCLUSION

Atopy should be taken into account when assessing the risk of severe exacerbations (that require hospital-based care) in wheezing infants; precautions should be taken against respiratory irritants and molds and to prevent children from becoming overweight.

Severe chronic allergic (and related) diseases: a uniform approach--a MeDALL--GA2LEN--ARIA position paper

Concepts of disease severity, activity, control and responsiveness to treatment are linked but different. Severity refers to the loss of function of the organs induced by the disease process or to the occurrence of severe acute exacerbations. Severity may vary over time and needs regular follow-up. Control is the degree to which therapy goals are currently met. These concepts have evolved over time for asthma in guidelines, task forces or consensus meetings. The aim of this paper is to generalize the approach of the uniform definition of severe asthma presented to WHO for chronic allergic and associated diseases (rhinitis, chronic rhinosinusitis, chronic urticaria and atopic dermatitis) in order to have a uniform definition of severity, control and risk, usable in most situations. It is based on the appropriate diagnosis, availability and accessibility of treatments, treatment responsiveness and associated factors such as comorbidities and risk factors. This uniform definition will allow a better definition of the phenotypes of severe allergic (and related) diseases for clinical practice, research (including epidemiology), public health purposes, education and the discovery of novel therapies.

Pathophysiology of asthma: lessons from genetic research with particular focus on severe asthma

There is good evidence that both inherited and environmental factors influence the risk of developing asthma. Only recently, large well-designed studies have been undertaken with the power to identify the genetic causes for asthma, and methods developed in parallel with the Human Genome Project, such as gene expression and epigenetic studies, have made large-scale analyses of functional genetics possible. In this review, we discuss the recent findings from genetic and genomic research studies of asthma, particularly severe asthma, and highlight specific genes for which there are multiple lines of evidence for involvement in asthma pathogenesis. Bio-ontologic enrichment analyses of the most recently identified asthma-related genes point to attributes such as 'molecular and signal transducer activity' and 'immune system processes', which indicates the importance of immunoregulation and inflammatory response in the pathogenesis of asthma. Finally, we discuss how genetic and environmental factors jointly influence asthma susceptibility and summarize how the results may increase understanding of the pathophysiology of asthma-related diseases.

Prevention and control of childhood asthma and allergy in the EU from the public health point of view: Polish Presidency of the European Union

The leading priority for the Polish Presidency of the Council of the European Union was to reduce health inequalities across European societies, and, within its framework, prevention and control of respiratory diseases in children. This very important paper contain proposal of international cooperation on the prevention, early detection and monitoring of asthma and allergic diseases in childhood which will be undertaken by the EU member countries as a result of EU conclusion developed during the Polish Presidency of the Council of the European Union. This will result in collaboration in the field of chronic diseases, particularly respiratory diseases, together with the activity of the network of national institutions and NGOs in this area. Paper also contains extensive analysis of the socio-economic, political, epidemiological, technological and medical factors affecting the prevention and control of childhood asthma and allergy presented during Experts presidential conference organized in Warsaw-Ossa 21–22 September 2011.

Understanding the complexity of IgE-related phenotypes from childhood to young adulthood: a Mechanisms of the Development of Allergy (MeDALL) seminar

Mechanisms of the Development of Allergy (MeDALL), a Seventh Framework Program European Union project, aims to generate novel knowledge on the mechanisms of initiation of allergy. Precise phenotypes of IgE-mediated allergic diseases will be defined in MeDALL. As part of MeDALL, a scientific seminar was held on January 24, 2011, to review current knowledge on the IgE-related phenotypes and to explore how a multidisciplinary effort could result in a new integrative translational approach. This article provides a summary of the meeting. It develops challenges in IgE-related phenotypes and new clinical and epidemiologic approaches to the investigation of allergic phenotypes, including cluster analysis, scale-free models, candidate biomarkers, and IgE microarrays; the particular case of severe asthma was reviewed. Then novel approaches to the IgE-associated phenotypes are reviewed from the individual mechanisms to the systems, including epigenetics, human in vitro immunology, systems biology, and animal models. The last chapter deals with the understanding of the population-based IgE-associated phenotypes in children and adolescents, including age effect in terms of maturation, observed effects of early-life exposures and shift of focus from early life to pregnancy, gene-environment interactions, cohort effects, and time trends in patients with allergic diseases. This review helps to define phenotypes of allergic diseases in MeDALL.

The investigation of asthma phenotypes

PURPOSE OF REVIEW

Asthma is a heterogeneous disease constituted by overlapping separate syndromes. This review discusses recent published data relevant to asthma and severe asthma classification, resting either on the 'candidate' approach based on criteria chosen by experts or on the 'exploratory' approach based on unsupervised statistical methods.

RECENT FINDINGS

Following the 'candidate' approach, groups of experts recently reviewed the classification of severe asthma to be applicable in low-income, milddle-income, and high-income countries and provided a systematic algorithm to diagnose severe refractory asthma. The concept of asthma endotypes involving different biological mechanisms has recently being proposed. Results from the 'exploratory' approach support the clinical heterogeneity in severe asthma and the need for new approaches for the classification of asthma severity. The novel childhood and adult asthma phenotypes recently identified using the exploratory approach were supported by first evidence of validity (replication in independent studies, assessment of their discriminative properties, and effect on clinical prognosis).

SUMMARY

Research on asthma phenotypes has increased exponentially in the last year. The main focus has been on severe asthma, likely due to its clinical and socioeconomic burden. Interestingly, many of the phenotypes identified are stable across populations and methodological approaches. Further analyses on the asthma phenotypes are needed to address their stability over time and their relevance from clinical and etiological perspectives.

Systems medicine and integrated care to combat chronic noncommunicable diseases

We propose an innovative, integrated, cost-effective health system to combat major non-communicable diseases (NCDs), including cardiovascular, chronic respiratory, metabolic, rheumatologic and neurologic disorders and cancers, which together are the predominant health problem of the 21st century. This proposed holistic strategy involves comprehensive patient-centered integrated care and multi-scale, multi-modal and multi-level systems approaches to tackle NCDs as a common group of diseases. Rather than studying each disease individually, it will take into account their intertwined gene-environment, socio-economic interactions and co-morbidities that lead to individual-specific complex phenotypes. It will implement a road map for predictive, preventive, personalized and participatory (P4) medicine based on a robust and extensive knowledge management infrastructure that contains individual patient information. It will be supported by strategic partnerships involving all stakeholders, including general practitioners associated with patient-centered care. This systems medicine strategy, which will take a holistic approach to disease, is designed to allow the results to be used globally, taking into account the needs and specificities of local economies and health systems.