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Wise et al.

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phenomena from true co-sensitization, resolve low-risk markers from high-risk markers of disease activity, and may improve the indication and selection of suitable allergens for AIT when compared to diagnosis based on SPT and/or sIgE determination with raw commercial extracts. 980-984 Indeed, changes in immunotherapy prescription aided by MD have been demonstrated to be cost-effective in some scenarios. 985 Certain patterns of sensitization to grass or olive pollen allergens may also identify patients with higher risk of adverse reaction during immunotherapy. 986,987 Nevertheless, all in vitro test results should be evaluated alongside the clinical history, since allergen sensitization does not necessarily imply clinical responsiveness. IgE to purified or recombinant allergens is usually measured by using a fluorescence enzyme immunoassay in singleplex platforms. However, a multiplex platform with 112 allergens is also available (ISAC, Thermo Fisher Scientific, Uppsala, Sweden). Results of singleplex and multiplex platforms are not interchangeable. When comparing the singleplex and multiplex assays, concordance of results vary between allergens tested, and the sensitivity of multiplex platform is lower than that of singleplex, particularly when sIgE levels are low. 983 Otherwise singleplex platforms are quantitative assays and multiplex are semiquantitative. Specific antigens.: In the case of mite sensitivity, markers of specific sensitization include Der p 1 and Der p 2 for Dermatophagoides pteronyssinus and Dermatophagoides farinae, 988 Lep d 2 for Lepidoglyphus destructor (storage mite, with limited cross-reactivity with other HDMs), 989 and Blo t 5 for Blomia tropicalis (non-Pyroglyphidae mite). 990 Der p 10, a tropomyosin from D. pteronyssinus , has been shown to be a good maker of clinical sensitivity to crustaceans but not a marker of sensitization to mites. 991,992 Can f 1, Can f 2, and Can f 5 are specific allergen components indicating specific sensitization to dog. 993 Interestingly, Can f 5, a prostatic kallikrein produced only by male dogs is responsible for monosensitivity in up to 25% to 38% of dog-allergic patients. 994,995 In these cases, patients can tolerate exposure to female dogs. Fel d 1 is the major allergen component in cat allergy, indicating specific sensitization. 996 Other cat allergens have some cross-reactivity with allergens from other sources; eg, Fel d 2 is likely to cross-react with other mammal albumins, such as dog Can f 3, horse Ecu c 3, pig Sus s PSA, and cow Bos d 6, 997 and Fel d 4 is shown to cross-react with major allergens from horse Equ c 1, dog, or cow. 998 Therefore, CRD for cat allergy provides more information about cross-reactivity and specificity of the diagnosis. Equ c 1, is the major allergen of horse dander and has some cross-reactivity with mouse Mus m 1 and cat Fel d 4. 999 Equ c 3 is a serum albumin showing cross-reactivity with other mammals’ serum albumins mentioned above (i.e. Fel d 2). In summary, CRD in patients with allergy to dog, cat, and horse are not only predictive markers of allergy, but may also help clinicians to predict clinical symptoms and their severity, since some patterns of sensitization are related to more severe rhinitis and asthma. 994,995 Allergens related to sensitization to cockroaches are Bla g 1, Bla g 2, Bla g 4, and Bla g 5, although in certain populations tropomyosins (Bla g 7 and/or Per a 7) can be important. 1000 Alt a 1 is a major allergen that is recognized in approximately 80% to 100% of Alternaria - allergic patients. 1001 Markers of sensitization to several pollen are summarized in Table

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Int Forum Allergy Rhinol . Author manuscript; available in PMC 2020 June 10.