A 'Difficult' Insect Allergy Patient
A 'Difficult' Insect Allergy Patient
There are many species of Hymenoptera capable of inducing anaphylaxis; commercially available extracts exist for only a small proportion of these. Although there is substantial cross-reactivity among venoms of closely related species of Hymenoptera, some species do have unique antigens that do not cross-react with other members of the genus. One notable example is the unique antigenicity of Vespula squamosa (Southern Yellow Jacket) among the other yellow-jacket venoms studied. The commercially available extracts for Vespula in North America consist of mixtures of venom from multiple yellow-jacket species. While V. squamosa is included in the commercially available yellow-jacket venom extract mixes, it highlights the possibility that species not included in the mixes may result in missed identification of venom-sensitized patients. These mixes do contain other European species that are invasive globally, and therefore may be used to identify Vespula-sensitized patients in other countries. The possibility, however, remains that native species not included in this mixture may be the primary sensitizer of patients in other countries. Species composition varies geographically, even within North America.
Missing sensitized patients is less problematic with species of Dolichovespula because of the smaller number of closely related species. Of the five species in North America, only two species (D. arnenaria and D. maculata) are commonly encountered and linked to hypersensitivity reactions. There are commercially available extracts to both of these species. North American Dolichovespula are presumed to overlap in antigens with species common in Europe (D. media, D. saxonica and D. sylvestris).
As with Vespula extracts, the commercially available extracts of Polistes venom in North America are mixes from a handful of species, venom from the majority of the 21 North American species not included. Because of the close phylogenetic relationship of these North American paper wasps, the mixes are expected to identify most cases of hypersensitivity. The possibility of missing sensitization, however, exists in those species that are less commonly encountered that are not included in these mixes. Because of difficulty in collecting all species for the yellow-jacket and paper wasp venom mixes, not all lots contain every species (according to the Hollister–Steir insert) (Table 1).
Unfortunately, there is limited cross-reactivity between the North American species and European species of paper wasp. This is of major concern in selecting extracts in countries outside North America. In addition, Polistes dominulus (European paper wasp) is now a widespread, invasive species in North America, with no commercially available extracts for this species available in North America and elsewhere. This species highlights the growing concern for invasive species in which phylogenetically distinct insects may not be identified using extracts from native species.
Anaphylaxis to Vespa crabro (the invasive European hornet), another invasive species to North America, appears to be rare, although there are no commercially available extracts to conduct skin testing for this species in North America. Because of extensive cross-sensitization, Vespula extracts may be useful in diagnosing and desensitizing patients with Vespa crabro sensitization; however, it is not clear whether this can be extended to other Vespa species.
Failure to identify venom-sensitized patients is a particular challenge in those sensitized to bumble bee, where there are no commercially available extracts for any of the 54 native species encountered in North America, and to Bombus terrestris, an imported European species used for commercial pollination. Bumble bee-induced anaphylaxis is best described for those with occupational exposure; however, the possibility exists that others may be missed when only honey bee venom is used in diagnostics. There is incomplete cross-reactivity in these different genera.
Venom Content
There are many species of Hymenoptera capable of inducing anaphylaxis; commercially available extracts exist for only a small proportion of these. Although there is substantial cross-reactivity among venoms of closely related species of Hymenoptera, some species do have unique antigens that do not cross-react with other members of the genus. One notable example is the unique antigenicity of Vespula squamosa (Southern Yellow Jacket) among the other yellow-jacket venoms studied. The commercially available extracts for Vespula in North America consist of mixtures of venom from multiple yellow-jacket species. While V. squamosa is included in the commercially available yellow-jacket venom extract mixes, it highlights the possibility that species not included in the mixes may result in missed identification of venom-sensitized patients. These mixes do contain other European species that are invasive globally, and therefore may be used to identify Vespula-sensitized patients in other countries. The possibility, however, remains that native species not included in this mixture may be the primary sensitizer of patients in other countries. Species composition varies geographically, even within North America.
Missing sensitized patients is less problematic with species of Dolichovespula because of the smaller number of closely related species. Of the five species in North America, only two species (D. arnenaria and D. maculata) are commonly encountered and linked to hypersensitivity reactions. There are commercially available extracts to both of these species. North American Dolichovespula are presumed to overlap in antigens with species common in Europe (D. media, D. saxonica and D. sylvestris).
As with Vespula extracts, the commercially available extracts of Polistes venom in North America are mixes from a handful of species, venom from the majority of the 21 North American species not included. Because of the close phylogenetic relationship of these North American paper wasps, the mixes are expected to identify most cases of hypersensitivity. The possibility of missing sensitization, however, exists in those species that are less commonly encountered that are not included in these mixes. Because of difficulty in collecting all species for the yellow-jacket and paper wasp venom mixes, not all lots contain every species (according to the Hollister–Steir insert) (Table 1).
Unfortunately, there is limited cross-reactivity between the North American species and European species of paper wasp. This is of major concern in selecting extracts in countries outside North America. In addition, Polistes dominulus (European paper wasp) is now a widespread, invasive species in North America, with no commercially available extracts for this species available in North America and elsewhere. This species highlights the growing concern for invasive species in which phylogenetically distinct insects may not be identified using extracts from native species.
Anaphylaxis to Vespa crabro (the invasive European hornet), another invasive species to North America, appears to be rare, although there are no commercially available extracts to conduct skin testing for this species in North America. Because of extensive cross-sensitization, Vespula extracts may be useful in diagnosing and desensitizing patients with Vespa crabro sensitization; however, it is not clear whether this can be extended to other Vespa species.
Failure to identify venom-sensitized patients is a particular challenge in those sensitized to bumble bee, where there are no commercially available extracts for any of the 54 native species encountered in North America, and to Bombus terrestris, an imported European species used for commercial pollination. Bumble bee-induced anaphylaxis is best described for those with occupational exposure; however, the possibility exists that others may be missed when only honey bee venom is used in diagnostics. There is incomplete cross-reactivity in these different genera.
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