Chemical immunology and allergy最新文献

The earliest known evidence of peanut farming dates back 7,600 years. With a prevalence of roughly 1%, peanut allergy is a diagnostic and treatment challenge, but is also a very good model for studying all aspects of food allergy, including its molecular basis and pathomechanisms. Therefore, the very starting point for elucidating all these aspects is the identification of peanut allergens with subsequent clearing of their structure and their preparation as pure recombinant and/or natural allergens. This is the basis for in vitro diagnostic tests as well as the development of immunotherapeutic drugs. With regard to class I food allergy, peanut allergy affects by far the largest group of patients. In peanuts, 12 allergens have been identified and their molecular characteristics are described herein. Ara h 1, Ara h 3.01 and Ara h 3.02 (the former Ara h 4) belong to the cupin superfamily. The conglutins Ara h 2, Ara h 6 and Ara h 7, and the non-specific lipid transfer protein Ara h 9 belong to the prolamin superfamily. Ara h 5 (profilin) and Ara h 8 (Bet v 1-homologous protein) cause class II food allergies and are associated with inhalation allergy to pollen via the sequential and/or conformational similarity of molecules. Two peanut oleosins are listed as Ara h 10 and Ara h 11 and two defensins as Ara h 12 and Ara h 13 by the WHO/IUIS Allergen Nomenclature Subcommittee. The effect of the above-specified allergens has to be considered in the context of their matrix, which is influenced by processing factors and the individual's immune system.

The synthesis and the identification of histamine marked a milestone in both pharmacological and immunological research. Since Sir Henry Dale and Patrick Laidlaw described some of its physiological effects in vivo in 1910, histamine has been shown to play a key role in the control of gastric acid secretion and in allergic disorders. Using selective agonists and antagonists, as well as molecular biology tools, four histamine receptors (H1R, H2R, H3R and H4R) have been identified. The Nobel Prize in Physiology and Medicine was awarded to Daniel Bovet in 1957 for the discovery of antihistamines (anti-H1R) and to Sir James Black in 1988 for the identification of anti-H2R antagonists. Anti-H1R and anti-H2R histamine receptor antagonists have revolutionized the treatment of certain allergic disorders and gastric acid-related conditions, respectively. More recently, anti-H3R antagonists have entered early-phase clinical trials for possible application in obesity and a variety of neurologic disorders. The preferential expression of H4R by several immune cells and its involvement in the development of allergic inflammation provide the rationale for the use of anti-H4R antagonists in allergic and in other immune-related disorders.

Allergic diseases triggered by mite allergens include allergic rhinoconjunctivitis, asthma, atopic dermatitis and other skin diseases. Since the early discovery of the allergenic role of mites of the genus Dermatophagoides in the mid 1960s, numerous species have been described as the source of allergens capable of sensitizing and inducing allergic symptoms in sensitized and genetically predisposed individuals. The main sources of allergens in house dust worldwide are the fecal pellets of the mite species D. pteronyssinus, D. farinae, Euroglyphus maynei and the storage mites Blomia tropicalis, Lepidoglyphus destructor and Tyropahgus putrescentiae. Group 1 and 2 allergens are major house dust mite allergens. The main allergens in storage mites include fatty acid-binding proteins, tropomyosin and paramyosin homologues, apolipophorin-like proteins, α-tubulins and others, such as group 2, 5 and 7 allergens. Cross-reactivity is an important and common immunological feature among mites. Currently, purified native or recombinant allergens, epitope mapping, proteomic approaches and T cell proliferation techniques are being used to assess cross-reactivity. Mites contain potent enzymes capable of degrading a wide range of substrates. Most mite allergens are enzymes. Advances in genomics and molecular biology will improve our ability to understand the genetics of specific IgE responses to mites. Mite allergen avoidance and immunotherapy are the only two allergen-specific ways to treat mite-induced respiratory and cutaneous diseases.

Chronic allergic inflammatory diseases are characterized by tissue damage with consequent remodeling including fibrosis and angiogenesis. Eosinophils are usually recruited to sites of allergic inflammation infiltrating the tissues as fully differentiated cells. In the last two decades, these cells have been characterized as a proangiogenic. The inadequate blood supply together with a high consumption of oxygen by the infiltrated cells is the main cause of tissue hypoxia in inflammation. Infiltrated eosinophils respond to hypoxia by increasing their viability and proangiogenic potential and regulate the expression of receptors particularly CD300a.

The discovery of histamine, its physiological role and reversal of its pharmacological effects by antihistamines takes us on a journey through the origins of modern physiology and the rising understanding of pharmacology at the end of the 19th and the early part of the 20th centuries. This journey, which has been traced in the excellent historical review by Michael Emanuel [Clin Exp Allergy 1999;29:1-11], is populated by some of the greatest scientists of the era, including six Nobel laureates - Bovet, Dale, Ehrlich, Richet, Windaus and Black. In addition, it laid the basis of medicinal chemistry not only for antihistamines, but also for the discovery of a plethora of drugs still in use today.

Allergic contact dermatitis is one of the most important dermatologic disorders worldwide - it can cause significant morbidity and decreased quality of life, as well as having major economic implications and loss of vocational productivity. Patch testing is the most important discovery in allergic contact dermatitis and the best diagnostic modality to date; the thin-layer rapid- use epicutaneous (TRUE) test is a more recent patch test development which has improved the convenience and feasibility of the test. The future of allergic contact dermatitis is bright as we continue to learn more about the science of the disorder, as well as ways to improve diagnosis and patient care. Furthermore, it is important to remember, in this global age, that cooperation between health care providers worldwide is essential.

Before the arrival of modern pharmacotherapy, drug hypersensitivity reactions were virtually unknown. Toxicity from the many plant-, animal- and inorganic material-derived remedies must have been much more common. One famous example is the intoxications from mercury, which has been used in many ailments, but particularly for the treatment of syphilis. It was only in the 19th century when more and more active principles from e.g. plants were identified, and when the observations of skin reactions became more prevalent. In 1877, Heinrich Köbner used for the first time the term 'drug exanthema' (Arznei-Exanthem). Since then, many different types of exanthemas from the mild macular-papular forms to the severe life-threatening bullous exanthemas such as toxic epidermal necrolysis have been observed from numerous drugs. The systematic investigation of severe drug reactions has only started in the second half of the 20th century, parallel to the increasing knowledge in immunology. Drug hypersensitivity reactions still remain one of the most challenging problems in allergology due to their manifold clinical manifestations and their very diverse pathophysiology. The introduction of new drugs and in turn the emergence of new hypersensitivity reactions will remain a challenge in the future.

Basophils were discovered by Paul Ehrlich in 1879 and account for less than 1% of blood leukocytes, which suggests a tightly controlled regulation of basopoiesis. The conservation of basophils in a wide spectrum of the animal kingdom suggests a non-redundant role in innate and adaptive immunity. In the early 1990s, it was demonstrated that murine and human basophils synthesize interleukin (IL)-4 and IL-13, thereby suggesting that these cells are important for Th2 polarization and IgE synthesis. Human basophils also synthesize IL-3, VEGFs and other pro-angiogenic molecules. Recently, various groups have introduced the use of basophil-depleting antibodies or have developed transgenic mice that constitutively lack basophils by more than 90%. These models have highlighted previously unrecognized roles of basophils, distinct from those played by mast cells, in innate and adaptive immunity. Although the physiologic role of basophils remains unknown, there is now compelling evidence that basophils, despite their small numbers in peripheral blood and inflamed tissues, are critically involved in a wide spectrum of immunologic disorders (allergic, autoimmune and infectious diseases, immunodeficiencies and cancer). It is not inconceivable that basophils and/or their products could be promising therapeutic targets for such disorders.