Allergens insects

In general, sensitization to insects occurs in about 30% of individuals with high-risk exposure. Allergenic insects are not only found at home but frequently in various types of work places which favor the exposure to a number of insect species concurrently. Storage pests are also an important consideration in workers exposed at their workplace as demonstrated in recent studies from Spain and South Africa. Prevalence rates of up to 50% for insects such as cockroaches, mealworms, and mites were documented. While the sensitization to these insects most probably occurred via the inhalational route, cross-contamination of grain and subsequently the end-products can also be expected. 

Allergens Pollutants that may cause an allergy, including pollens, dusts, animal dander, insect debris, mold and fungi spores. 

The classical skin response to local release of histamine that results from contact with an allergen, irritant or following an insect bite. A central wheal develops as a direct result of local inflammation and the the oedema the follows the increased capillary permeability caused by histamine acting on HI-receptors on vascular-endothelial cells. 

Anaphylaxis most commonly starts with symptoms on the skin or the respiratory tract (table 2). The symptomatology is variable there is no obligatory involvement of all organ systems. A major characteristic of anaphylaxis is the rather rapid onset of symptoms after contact with the elicitor. The interval varies between a few seconds or minutes until 1 or 2 h, partly dependent upon the route of application (rapid onset after intravenous allergen exposure) and degree of sensitization. Experience in insect sting anaphylaxis in... 

A number of allergens from both honey bee and vespid venoms have been cloned and expressed by either Escherichia coli or baculovirus-infected insect cells (table 1) phospholipase Aj [20], hyaluronidase [21], acid phosphatase [13] and Api m6 [14] from honey bee venom, as well as antigen 5 [22], phospholipase A and hyaluronidase [23] from vespid venom, and dipeptidylpeptidases from both bee and Vespula venoms [15, 16]. Their reactivity with human-specific IgE antibodies to the respective allergens has been documented [11-16, 22, 23] and their specificity is superior... 

While in anaphylaxis caused by other frequent elicitors like food and drugs, allergen-specific immunotherapy is not established, immimotherapy with Hymenoptera venoms has been shown to be effective in three prospective controlled trials (table 4) [38-40] and also in a number of studies where patients were submitted to a sting challenge with the responsible insect during venom immimotherapy (table 5) [44]. While over 90% of vespid venom-allergic patients are fully protected and do not develop any... 

Grunwald T, Bockisch B, Spillner E, Ring J, Brede-horst R, Ollert M Molecular cloning and expression and expression in insect cells of honey bee venom allergen acid phosphatase (Api m3). J Allergy Clin Immunol 2006 117 848-854. 

If possible, refer patient to allergen-specific immunotherapy (e.g. insect venom anaphylaxis)... 

Blum MS (1984) Poisonous ants and their venoms. In Tu AT (ed) Handbook of natural toxins, vol 2. Insect poisons, allergens, and other invertebrate venoms. Marcel Dekker, New York, p 225... 

Witteman, A.M., et al. (1994). Identification of a cross-reactive allergen (presumably tropomyosin) in shrimp, mite and insects, Int. Arch. Allergy Immunol., 105, 1, 56-61. 

The tropomyosins of mite and insect species show some sequence identity (63-65%) with snail tropomyosin and share similar epitopes (EFSA, 2006 Fig. 4.1). Still, tropomyosin appears to play a minor role in the crossreactivity of dust mites and snails (Asturias et ah, 2002 Guilloux et ah, 1998 Van Ree et ah, 1996a). Other non-tropomyosin allergens are likely to be involved including Der p 4 (amylase), Der p 5, Der p 7, and hemocyanin (Martins et ah, 2005 Mistrello et ah, 1992 Van Ree et ah, 1996). While snail is the main molluscan shellfish species involved in cross-reactions with dust mites, some patients allergic to dust mites and snails are also sensitized to mussels (DeMaat-Bleeker et ah, 1995 Van Ree et ah, 1996b). In their study of 70 patients sensitized to molluscan shellfish, Wu and Williams (2004) noted that 90% were also sensitized to dust mites. However, the clinical significance of this sensitization was not documented. 

Compounds (I) through (IV) were assayed for their cytotoxic and allergenic potential on guinea pigs, which are effective indicators of contact allergenicity in humans (10). The same compounds were also tested on Tenebrlo sp. (mealworm beetles), an experimental Insect used to test the potential of insecticides. Geranyl-benzoquinone proved to be a very potent elicitor of allergic skin reactions as well as a potent insecticide (10). 

Tu, A.T., Insect Poisons, Allergens, and Other Invertebrate Venoms, Marcel Dekker, New York, 1984. 

Long before Bt crops were developed, Bt toxins in sprayable formulations were used to control insects. This fact allowed the EPA and FDA to consider twenty years of human exposure in assessing human safety before agreeing to register Bt corn for commercial use. In addition to these data, numerous toxicity and allergenicity tests were conducted on many different kinds of naturally occurring Bt toxins. Based on these tests and the history of Bt use on food crops, it was concluded that Bt corn is as safe as its conventional counterpart and therefore would not adversely effect human and animal health or the environment (Opinion on..., EFSA 2004). 

Diagnostic methods include SPT and quantification of specific IgE antibodies can be done using assays such as the ImmunoCAP or allergen-microarray. However, positive test results do not necessary confirm clinical sensitivity. Possible crossreactivity between tropomyosin from crustacean and mollusks with tropomyosin from insects and mites may have clinical significance and is discussed below. Sampson and Ho (1997) attempted to establish IgE values to predict clinical... 

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