Concept: Allergen immunotherapy
An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen
- Allergy, asthma, and clinical immunology : official journal of the Canadian Society of Allergy and Clinical Immunology
- Published over 2 years ago
Cats are the major source of indoor inhalant allergens after house dust mites. The global incidence of cat allergies is rising sharply, posing a major public health problem. Ten cat allergens have been identified. The major allergen responsible for symptoms is Fel d 1, a secretoglobin and not a lipocalin, making the cat a special case among mammals.
Allergy immunotherapy targets the immunological cause of allergic rhinoconjunctivitis and allergic asthma and has the potential to alter the natural course of allergic disease.
Anaphylaxis is an acute severe reaction involving multiple systems that results from a rapid release of inflammatory mediators. Patients with asthma and prior allergic reactions are at risk for anaphylaxis. Infants can present a special challenge, as the hallmark symptoms and signs of anaphylaxis may be mistaken as normal findings. These include drooling, vomiting or diarrhea, scratching, and drowsiness. The clinical manifestations of anaphylaxis are broad, as a result of it being a systemic response to an external agent. Among infants and children, there are often respiratory and cutaneous findings. There also can be subtle signs and symptoms, which can often be missed or the findings misinterpreted as normal for developmental age. The incidence of anaphylaxis has increased globally among children presenting with allergic reactions. Early recognition of the signs and symptoms is crucial to effective diagnosis and treatment. This is particularly true among infants 13 months of age or younger who are nonverbal and may have subtle signs and symptoms of a life-threatening reaction to allergens. The purpose of this article is to highlight the differential clinical presentations of young children with anaphylaxis.
The National Academies of Sciences, Engineering, and Medicine convened an expert, ad hoc committee to examine critical issues related to food allergy. The authors of the resulting report, “Finding a Path to Safety in Food Allergy: Assessment of the Global Burden, Causes, Prevention, Management, and Public Policy,” evaluated the scientific evidence on the prevalence, diagnosis, prevention, and management of food allergy and made recommendations to bring about a safe environment for those affected. The committee recommended approaches to monitor prevalence, explore risk factors, improve diagnosis, and provide evidence-based health care. Regarding diagnostics, emphasis was placed on utilizing allergy tests judiciously in the context of the medical history because positive test results are not, in isolation, diagnostic. Evidence-based prevention strategies were advised (for example, a strategy to prevent peanut allergy through early dietary introduction). The report encourages improved education of stakeholders for recognizing and managing as well as preventing allergic reactions, including an emphasis on using intramuscular epinephrine promptly to treat anaphylaxis. The report recommends improved food allergen labeling and evaluation of the need for epinephrine autoinjectors with a dosage appropriate for infants. The committee recommended policies and guidelines to prevent and treat food allergic reactions in a various settings and suggested research priorities to address key questions about diagnostics, mechanisms, risk determinants, and management. Identifying safe and effective therapies is the ultimate goal. This article summarizes the key findings from the report and emphasizes recommendations for actions that are applicable to pediatricians and to the American Academy of Pediatrics.
Molecular-based allergy (MA) diagnostics is an approach used to map the allergen sensitization of a patient at a molecular level, using purified natural or recombinant allergenic molecules (allergen components) instead of allergen extracts. Since its introduction, MA diagnostics has increasingly entered routine care, with currently more than 130 allergenic molecules commercially available for in vitro specific IgE (sIgE) testing.MA diagnostics allows for an increased accuracy in allergy diagnosis and prognosis and plays an important role in three key aspects of allergy diagnosis: (1) resolving genuine versus cross-reactive sensitization in poly-sensitized patients, thereby improving the understanding of triggering allergens; (2) assessing, in selected cases, the risk of severe, systemic versus mild, local reactions in food allergy, thereby reducing unnecessary anxiety for the patient and the need for food challenge testing; and (3) identifying patients and triggering allergens for specific immunotherapy (SIT).Singleplex and multiplex measurement platforms are available for MA diagnostics. The Immuno-Solid phase Allergen Chip (ISAC) is the most comprehensive platform currently available, which involves a biochip technology to measure sIgE antibodies against more than one hundred allergenic molecules in a single assay. As the field of MA diagnostics advances, future work needs to focus on large-scale, population-based studies involving practical applications, elucidation and expansion of additional allergenic molecules, and support for appropriate test interpretation. With the rapidly expanding evidence-base for MA diagnosis, there is a need for allergists to keep abreast of the latest information. The aim of this consensus document is to provide a practical guide for the indications, determination, and interpretation of MA diagnostics for clinicians trained in allergology.
- Current opinion in allergy and clinical immunology
- Published over 7 years ago
PURPOSE OF REVIEW: Nonspecific lipid transfer protein (LTP) is the main cause of primary food allergy in adults living in the Mediterranean area. The way allergic patients get sensitized to this protein is all but established, and the clinical expression of sensitization is extremely variable, ranging from long-lasting symptomless sensitization to severe anaphylaxis. Such variability is seemingly due to the presence/absence of a number of cofactors. RECENT FINDINGS: The possibility that LTP sensitization occurs via the inhalation of LTP-containing pollen particles seems unlikely; in contrast, peach particles containing the protein seem able to sensitize both via the airways and the skin. Cosensitization to pollen allergens as well as to labile plant food allergens makes LTP allergy syndrome less severe. In some LTP sensitized subjects clinical food allergy occurs only in the presence of cofactors such as exercise, NSAIDs, or chronic urticaria. SUMMARY: Lipid transfer protein allergy syndrome shows some peculiarities that are unique in the primary food allergy panorama: geographical distribution, frequent asymptomatic sensitization, frequent need for cofactors, and reduced severity when pollen allergy is present. Future studies will have to address these points as the results may have favorable effects on other, more severe, types of food allergy.
Peamaclein - A new peach allergenic protein: similarities, differences and misleading features compared to Pru p 3
- Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology
- Published over 7 years ago
Among the peach-derived allergens which are already known, the lipid transfer protein (Pru p 3) seems to be the one to exert severe allergic reactions.
A symposium entitled “Advances in Food Allergen Detection” was held at the 243rd American Chemical Society Meeting in March 2012 in San Diego, CA and was sponsored by the ACS Division of Agricultural and Food Chemistry. The purpose of the symposium was to convene the leaders in the food allergen analysis field for presentations on, and discussions of, the state of the art, new developments, and critical challenges in the detection and quantitation of allergenic proteins in foods. Twenty-five presentations were delivered by speakers representing academic, government and industrial institutions in ten countries. The presentations covered all aspects of food allergens, including a historical progress review, regulatory policies, clinical practices, food processing effects, food production equipment cross-contamination and cleaning, and the performance of several food allergen analytical strategies and technologies. This article is intended to provide a brief summary of the presentations as well as a record of the proceedings of the symposium, which was deemed a great success in advancing food allergen analysis.
ETHNOPHARMACOLOGICAL RELEVANCE: Xylopia aethiopica has been traditionally used in the form of the dried fruit decoction to treat bronchitis, asthma, arthritis and rheumatism in Ghana, Nigeria and Cameroon. AIM OF THE STUDY: To evaluate the anti-anaphylactic and anti-inflammatory effects of a 70% aqueous ethanol extract of the fruits of Xylopia aethiopica MATERIALS AND METHODS: Systemic anaphylaxis was induced by the injection of either compound 48/80 or lipopolysaccharide, LPS and survival rates of mice monitored for 1h or 7 days respectively while IgE-mediated anaphylaxis in a local allergic reaction was studied in the pinnal inflammation model in mice. Clonidine-induced catalepsy in mice was used to evaluate the indirect antihistamine effect of Xylopia aethiopica, XAE. The effects of XAE assessed on the maximal and total oedema responses in the carrageenan-induced paw oedema in mice was used to evaluate the anti-inflammatory action of the extract. RESULTS: Administered at 30,100,300 and 1000mgkg(-1) p.o., XAE dose dependently suppressed compound 48/80-induced mouse systemic anaphylactic shock and offered 63% protection to mice against LPS-induced endotoxic shock at a dose of 300mgkg(-1). In addition, the extract (30-300mgkg(-1)) in a dose dependent manner significantly inhibited by 23-62% the mouse pinnal inflammation. Clonidine-induced catalepsy in mice was significantly suppressed in a dose and time dependent manner when administered both prophylactically and therapeutically. In the same doses, when administered before the induction of the mouse carrageenan-induced paw oedema, the mean maximal swelling attained during 6h was reduced to 41.02±6.94%, 35.61±4.30%, and 29.09±4.90% of the inflamed control response respectively and total paw swellings induced over the 6h were also dose-dependently and significantly suppressed to 74.84±14.84%, 63.95±9.37%, and 48.13±10.90% of the inflamed control response respectively. Administered after the induction of the carrageenan paw oedema the mean maximal swelling attained during 6h was suppressed to 49.84±3.95%, 43.62±1.01%, and 35.97±1.34% of the inflamed control response respectively while the total paw swellings induced over the 6h were also dose-dependently and significantly suppressed at 100 and 300mgkg(-1) to 72.39±4.38% and 60.81±3.25% of the inflamed control response respectively CONCLUSION: These findings suggest that XAE inhibits mast cell-dependent immediate allergic reactions and exhibit anti-inflammatory actions through the inhibition of histamine release from mast cells via stabilizing the cell membrane. Our results contribute towards validation of the traditional use of Xylopia aethiopica in the treatment of bronchitis, asthma, arthritis and rheumatism.
Allergens produced by domestic mites (DM) are among the most common allergic sensitizers and risk factors for asthma. To compare exposure levels between workplaces and living areas a new assay able to measure airborne DM antigen concentrations was developed.