Cross-reactivity between cockroach allergens and arthropod, nematode and mammalian allergens

Cockroaches (CRs) are major indoor allergens that can pose a serious risk f or respiratory allergies in sensitized subjects. Recent evidence suggests t hat CR allergens crossreact with allergens present in insect and other inve rtebrates. IgE antibodies of insect-allergic subjects were shown to react w ith silverfish, CR and chironomid extracts. Cross-reactivity between house dust mites, silverfish, CR and chironomids and between cockroach and the re duviid, German CR and chironomids, and CRs crustacea species was establishe d by RAST inhibition. There is some evidence that CR cross-reacts with the nematodes Anisakis and Ascaris. No cross-reactivity has been demonstrated b etween CR and mammalian allergens. The protein implicated in the cross-reac tivity of CR with invertebrate allergens is tropomyosin. Tropomyosin has be en identified as a major allergen in shrimp and other crustacea, CR, dust m ites, and squid; these tropomyosins show substantial amino acid homology as well as immunological cross-reactivity. Clinical relevance of these cross- reactivities is suggested.