House-dust mites (HDM) are important sources of indoor allergens, and the frequency of sensitization to these allergens can be as high as 40% in the general population. HDM sensitization may give rise to allergic rhinitis, and it markedly increases the risk for asthma in the individual. Cross-reactivity between house dust mite allergens and other allergens, in particular those from other invertebrates (mites, insects, mollusks, and crustaceans) has long been suspected to cause or worsen food allergy, inhalation allergy, and local skin reactions.
House Dust Mites allergens:
The majority of HDM-allergic patients are co-sensitized to both Dermatophagoides pteronyssinus and Dermatophagoides farinae. These are the most prevalent HDMs, and allergens from both species are normally present in samples of house dust from temperate and tropical zones. HDMs contain at least 12 major allergenic proteins; in children, reactivity to Der p 1 and Der p 2 predominate whereas in newly diagnosed adults, other HDM allergens (Der p 3 and Der p 4) are major contributors to sensitization. Similarly, Der p 23 is a novel major allergen of HDM with a high reported prevalence among Dermatophagoides pteronyssinus-sensitized patients. Specific immunoglobulin E (sIgE) to Der p 23 is associated with many of the perennial asthmatic respiratory symptoms. Finally, Der p 10 is a tropomyosin and can cause cross-reaction with other related tropomyosins from crustaceans and mollusks. Across Dermatophagoides, there is a high sequence identity for Der p 10 and other tropomyosins.
Storage Mite allergens:
Storage mites are microbial grazers on decaying biologic matter and are routinely seen infesting various stored food products. A typical allergy test panel is comprised of four main storage mites including Acarus siro, Tyrophagus putrescentiae, Lepidoglyphus destructor, and Glycyphagus domesticus. Most reports confirm that HDM extracts can inhibit storage-mite-specific IgE-binding suggesting that the mites of these two families are closely related. What is the relationship between house dust mites and these other allergens? Like HDM, storage mites appear to have homologues for Der p 1 and Der p 2 that are more than 40% similar by DNA sequence. For HDMs, the tropomyosins are evolutionarily closer within the Dermatophagoides genus than to other storage mites; however, sensitization to Der p 10 can results in similar sensitization to storage mites.
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Cockroach allergens:
Many cockroach species exist worldwide (approximately 4,000 species), but only few are present in residential settings. Two species, the German (Blattella germanica) and American cockroach (Periplaneta americana) predominate in temperate and tropical areas; these cockroaches represent one of the most common sources of indoor allergens worldwide, and 40%-60% of asthma patients in urban areas possess IgE antibodies to cockroach allergens. It has been suggested that five primary cockroach proteins (Bla g 1, Bla g 2, Bla g 4, Bla g 5, and Bla g 7) trigger sensitization in 50–64% of allergic patients and these proteins can be related to HDM allergens for most sensitized patients. For example, antibodies raised against tropomyosin from HDM (Der p 10) react with Cockroach tropomyosin (Bla g 7), suggesting that this is one of the proteins involved in the cross-reactivity.
Crustacean allergens:
For shellfish, the major allergen is tropomyosin. Among 13 allergens studied from the shrimp Penaeus aztecus, the tropomyosin deemed Pen a1 was found to be present in nearly 80% of sensitized patients. In an epidemiological study with patients allergic to “shellfish” 82% appeared to also be sensitized to HDM, suggesting that a common reactivity amongst tropomyosin from invertebrates and HDMs. Based on this, the high structural homology present between allergenic proteins from apparently unrelated sources such as HDMs and crustaceans seem to play an important role in IgE-mediated poly sensitization and covariation of sensitization.
Tropomyosins are highly conserved in invertebrates and are among the major allergenic proteins causing a significant proportion of invertebrate allergies. Tropomyosins from mites, many crustaceans, and some domestic insects such as cockroaches are structurally very similar and share similar IgE-binding epitopes. This may therefore be a cause of clinically reported cross-reactivity.
The relationship between house dust mites and other allergens can affect patients year round. The peak breeding season for dust mites is May-October, but heating systems can stir up dust and circulate throughout the house. The proteins involved in cross-reactivity between house dust mites, including cockroach and crustacuean allergies, are likewise non-seasonal. NOVEOS is the the new standard in routine IgE testing allowing you to pinpoint true allergy triggers with accurate results. »Learn More
Available tests on NOVEOS:
Whole Allergen extract:
House Dust Mite | Dermatophagoides pteronyssinus | D001
House Dust Mite | Dermatophagoides farinae | D002
House Dust Mite | Dermatophagoides microceras | D003
Storage Mite | Acarus siro | D070
Storage Mite | Lepidoglyphus destructor | D071
Storage Dust Mite | Tyrophagus putrescentiae | D072
Storage Dust Mite | Glycyphagus domesticus | D073
House Dust Mite | Blomia tropicalis | D201
German Cockroach | Blattella germánica | I006
Allergen Component:
nDer p 1, House Dust Mite | Dermatophagoides pteronyssinus | D202
rDer p 2, House Dust Mite | Dermatophagoides pteronyssinus | D203
rDer p 10, Tropomyosin, House Dust Mite | Dermatophagoides pteronyssinus | D205
rDer p 23, House Dust Mite | Dermatophagoides pteronyssinus | D209
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