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Wise et al.

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VIII.F.6. Sensitization to profilin has been associated with more severe respiratory symptoms in grass-allergic patients, as well as sensitization to the minor olive allergens Ole e 7 and Ole e 9. 987,1002 IgE antibodies to Phl p 1 and/or Phl p 5 can be used as specific markers of sensitization to grass pollen and Phl p 4 as a marker of sensitization to non Pooideae grasses. However, Phl p 6 is contained only in Pooideae grasses. Allergens from groups 1, 2, 5 and 6 are only expressed in grasses but not in other plants, so they detect a genuine sensitization to grasses. 981 In summary, CRD in patients with AR can help to better define the sensitization to inhalant allergens, especially in those who are polysensitized, have unclear symptoms and/or sensitization patterns, or who do not respond to treatment. On the contrary, monosensitized patients with a clear case history and symptom profile may not benefit from CRD compared to traditional diagnostic tests. Nevertheless, CRD remains a third-level approach, not to be used as a screening method in current practice. One of the most useful aspects of CRD is that it can help clinicians to better select patients and allergens for prescribing AIT, 1003 and in some cases, predict the risk of adverse reactions. The pattern of sensitization to allergens may predict the severity of the disease and could potentially predict the efficacy of AIT, provided these immunotherapy products contain a sufficient amount of allergen. As there are multiple individual allergens available for CRD and several different uses for CRD, extensive evidence grading is not undertaken in this document. Sensitization vs allergy— Although IgE-mediated sensitization has been consistently shown to be an important risk factor for rhinitis, 520,1004 the strength of this association is not consistent. 1005,1006 In epidemiology and clinical practice, patients are typically diagnosed as being “sensitized” based on a positive SPT (usually ≥3 mm wheal diameter), or a positive specific serum IgE (usually ≥0.35 kU/L [specific IgEs are reported in arbitrary units, thus the unit kU]). 1007,1008 However, both of these tests can be positive in the absence of any symptoms, and neither positive SPT nor IgE can confirm the expression of rhinitis symptoms upon allergen exposure. 1009,1010 Thus, a clear distinction has to be made between “sensitization” (which usually refers to positive allergy tests, irrespective of any symptoms), and clinical allergic disease such as AR, which denotes the presence of sensitization and related clinical symptoms. “Positive” allergy test vs sIgE titer or SPT wheal size— Quantification of atopic sensitization by using the level of sIgE antibodies or the size of SPT wheals increases the specificity of allergy tests in relation to the presence and severity of rhinitis. 893,1004 This has changed the way we interpret the results of allergy tests, with a move from dichotomization (labeling patients as being sensitized based on a “positive” test using arbitrary criteria), to quantification of blood or skin tests using sIgE titer and SPT wheal size. 893,1010-1012 Whole-allergen extract vs individual allergenic molecules— Homologous proteins present in the whole-allergen extracts from different allergen sources may be cross-reactive (eg, profilins and PR-10 proteins in various plants, or tropomyosin present in mites, various insects, and shrimp). Thus, a positive test to the whole-allergen extract may reflect

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VIII.G. Sensitization vs clinical allergy

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