Chemical immunology and allergy最新文献

Given its increasing prevalence and potential severity, food allergy not only negatively impacts the health and quality of life of affected individuals but also carries a significant economic burden. To address these problems, a community approach including efforts to increase awareness of food allergy among the general public and the implementation of appropriate public policies to keep affected individuals safe is required. This chapter reviews the general public's knowledge and perceptions of food allergy, the disease's psychosocial impact on affected individuals, and the current state and future directions of food allergy public policy.

Despite a trend towards delayed weaning, food allergies (FAs) have increased in the past few decades and are now considered a public health concern, resulting in significant morbidity as well as occasional mortality. Whilst genetic factors are clearly important in the development of FA, a rise in FAs has occurred over a short period of time and is therefore unlikely to be due to germ-line genetic changes alone. Thus, it seems plausible that one or more environmental exposures may, via epigenetic changes, result in the interruption of the 'default immunologic state' of tolerance to foods. Strategies are therefore required for the prevention of FA: primary prevention seeks to prevent the onset of IgE-sensitisation; secondary prevention seeks to interrupt the development of FA in IgE-sensitised children; and tertiary prevention seeks to reduce the expression of 'end-organ' allergic disease in children with established FA. This chapter will outline the major findings in this field, with the aim of equipping the clinician with an evidence-based approach to a burgeoning yet poorly understood clinical problem. We also highlight the methodological challenges hindering the interpretation of existing FA studies. Fortunately, there are now robust studies underway, the results of which are expected to guide public health recommendations with respect to how and when to introduce major allergenic foods to children, regardless of allergic risk.

About 17% of German children and adolescents suffer from at least one of the following atopic illnesses: allergic rhinoconjunctivitis, atopic eczema or asthma. Consistent professional therapy is necessary to limit the health-related risks and improve these medical conditions. The consequences of a diagnosis often mean an additional task for the parents of diseased children, where they have to act simultaneously as an educator and therapist for their children. Structured educational programmes were developed for a few diseases such as asthma and atopic eczema in order to prepare parents and affected children to accept this important responsibility. Moreover, a structured programme for anaphylaxis is being developed. These proposals aim not only to transfer knowledge about the disease but also to effectively support self-reliant treatment and emotional coping with the disease as well as its collateral strain.

Molecular allergology is a breakthrough science that enables the quantification of IgE antibodies against individual allergen protein components at the molecular level. The diagnosis of IgE-mediated allergic disorders is based on the clinical history and on sensitization demonstrated through an allergy test. Identifying whether the sensitization is primary (species specific) or due to cross-reactivity with proteins with similar protein structures helps the clinician to judge the risk of allergic reaction. This is possible today because allergen component tests for food allergy are now available for clinicians to use in everyday practice.

The majority of research on food allergy has been bio-medical in orientation, focusing on issues such as the molecular structure of allergens, or aimed at methods of diagnosis. In the last decade, there has been a growing interest in the development of questionnaires that measure the impact of food allergy on health-related quality of life (HRQL). These studies have provided insight into the everyday burden of living with food allergy and have suggested ways that HRQL can be improved. The EuroPrevall project (europrevall@bbsrc.ac.uk) has given great impetus to research in the area of HRQL. In addition to clinical research on the prevalence, mechanisms and causes of food allergy, research output in the area of psycho-social impact has included HRQL measures for all age groups and examination of the socio-economic impact of food allergy. In this chapter, we review the literature on the impact of food allergy on children, teens and their parents; the majority of this data was generated over the life of the EuroPrevall project. We then examine both quantitative and qualitative research findings to provide an in-depth picture of the impact of food allergy on the concerns and everyday lives of children, teens, adults and parents. Research on factors that are related to and impact HRQL is also discussed. There is a strong emphasis throughout the chapter on developmental considerations of food allergy, spanning from infants to adults. We conclude by discussing methodological issues in relation to the measurement of HRQL in relation to food allergy. We offer some recommendations for future research and practice on HRQL so that HRQL measures can reach their full potential in research, practice and policy, with the help of the findings in this review. Overall, the findings suggest that food allergy has a strong impact on HRQL in terms of social, dietary, and psychological factors. 'Rules' and restrictions ostensibly apply to food, but because food is such an integral part of everyday life, these restrictions extend far beyond 'mealtimes'. Therefore, social events are experienced differently and have a different meaning for those living with food allergy, giving rise to feelings of exclusion and difference when compared to those without allergy. Children, teens, and parents need to cope with normal developmental changes as well as with the food allergy, placing them under increased psycho-social stress and leading to adverse effects on HRQL and coping. To address and attempt to alleviate such stressors, both quantitative and qualitative research suggests that targeting uncertainty should be a major goal for health professionals working with children, teens and families with a food allergy. Remarkable similarities in response to food allergy across countries suggest that policies and programmes that address quality of life issues may be relevant to many different populations. An in-depth understanding of the relationship between a diagnosis of food alle

Recent studies have suggested that the prevalence of food allergy is increasing in many parts of the world. However, many epidemiology studies have been based only on questionnaires without objective testing. The data from these studies do show that the pattern of food allergies is different across the world. In general, studies using objective testing reported a lower prevalence than those without objective testing. The most common food allergens are cow's milk, hen's egg, wheat, fish, shellfish, peanuts, and tree nuts. Recent evidence also suggested that some of these allergies might not persist longer than the childhood years. However, unlike milk and egg allergies, seafood allergy is more likely to persist into adulthood. Peanuts and tree nuts are some of the most common causes of anaphylaxis in developed countries, but these are rather rare in developing countries. Given the early evidence of an increasing prevalence of food allergies, continual monitoring of the changing prevalence and patterns in different countries should help us understand the true causes of food allergy.

The standardized therapeutic approach for food allergy is based on avoidance of allergens in foods. Oral immunotherapy (OIT) is a significant focus of food allergy research and appears to be effective in inducing desensitization. However, most patients receiving OIT have mild to moderate symptoms during the therapy, and it has not been clearly established whether OIT is effective in inducing permanent tolerance. Recently, novel therapeutic approaches for food allergy, or sublingual immunotherapy and epicutaneous immunotherapy using an anti-IgE monoclonal antibody (omalizumab), have been examined in some studies. These studies showed that the frequency of adverse reactions is lower than with OIT and that patients can increase their food tolerance. Other novel approaches, including the use of omalizumab in combination with OIT, may be useful in food allergy treatment. There is some evidence that a combination of OIT with omalizumab increases threshold doses of food without causing symptoms. OIT offers a new approach for treating food allergy, although further study is needed to demonstrate long-term safety and benefits in larger numbers of patients.

Dietary intervention is a crucial component of food allergy management but can negatively impact nutrient intake. A comprehensive nutrition assessment with appropriate intervention is warranted in all children with food allergies to meet nutrient needs and optimize growth. Nutrition assessment may also be indicated in adults with food allergy. Frequently, an elimination diet is absolutely necessary to prevent potentially life-threatening anaphylaxis. Allergen elimination can also improve chronic symptoms, such as atopic dermatitis, when a food is proven to trigger symptoms. Allergen elimination goals are to prevent acute and chronic food-allergic reactions in the safest and least restrictive environment to supply a balanced diet that promotes health in children and adults.

Fish and shellfish consumption has increased worldwide, and there are increasing reports of adverse reactions to fish and shellfish, with an approximate prevalence of 0.5-5%. Fish allergy often develops early in life, whilst shellfish allergy tends to develop later, from adolescence onwards. Little is known about the natural history of these allergies, but both are thought to be persistent. The clinical manifestations of shellfish allergy, in particular, may vary from local to life-threatening 'anaphylactic' reactions within an individual and between individuals. Parvalbumin and tropomyosin are the two major allergens, but several other allergens have been cloned and described. These allergens are highly heat and biochemically stable, and this may in part explain the persistence of these allergies. Diagnosis requires a thorough history, skin prick and in-vitro-specific IgE tests, and oral challenges may be needed for diagnostic confirmation. Strict avoidance of these allergens is the current standard of clinical care for allergic patients, and when indicated, an anaphylactic plan with an adrenaline auto-injector is prescribed. There are no published clinical trials evaluating specific oral immunotherapy for fish or shellfish allergy.

Although most food allergy patients have immediate-type reactions, some have delayed-type reactions. Unlike for the detection of food-specific IgE antibody in immediate-type (IgE-mediated) food allergies, only a few tests are currently available to aid in the diagnosis of delayed-type (non-IgE-mediated) food allergies. This chapter summarizes our current understanding of one in vitro test and one in vivo test for non-IgE-mediated food allergies: the lymphocyte stimulation test (LST) and the atopy patch test (APT). Although the LST is not yet standardized, a food protein-specific LST might be a useful tool for diagnosing delayed-type food allergies, and especially those manifesting with gastrointestinal symptoms but not skin symptoms. Various remaining issues - including basophil contamination of the peripheral blood mononuclear cell fraction and lipopolysaccharide contamination of food antigen preparations - are also discussed. The APT uses an epicutaneous patch technique to occlusively apply food antigens to the skin to induce inflammatory reactions at the patch application site. Because the APT shows modest sensitivity and specificity, the clinical benefit of the APT in the diagnosis of food allergies in patients with atopic dermatitis is limited. A position paper on the APT issued by the European Academy of Allergy and Clinical Immunology/Global Allergy and Asthma European Network in 2006 is briefly summarized, and several recent APT-related topics, including APT use for the diagnosis of food protein-induced enterocolitis syndrome, are discussed.