Mugwort-sensitized individuals from North Europe, South Europe and North America show different IgE reactivity patterns.

BACKGROUND: Sensitization to weed pollen allergens at the molecular level is not fully understood. We studied IgE reactivity to the major mugwort allergen Art v 1 in relation to allergens from other weed pollen and cross-reactive components in mugwort-sensitized subjects. METHODS: Art v 1 and Amb a 1 were affinity purified and coupled to experimental ImmunoCAP® tests. Samples from North Europe (n = 50), South Europe (n = 19) and North America (n = 41) were analyzed for IgE against mugwort pollen, weed allergen components, pan-allergens and cross-reactive carbohydrate determinants (CCDs). RESULTS: The prevalence of IgE reactivity (>0.35 kU(A)/l) to Art v 1 was significantly higher in samples from North Europe than in those from North America. IgE to Amb a 1 was more common in North America than in North and South Europe, while IgE to Par j 2 was common in South Europe, less common in North America, and absent in North Europe. IgE to Art v 3 in mugwort-allergic patients was more common in North Europe than in South Europe and North America, while IgE to Sal k 1 was similar between the areas. Subjects with an Art v 1/mugwort-specific IgE ratio <0.5 had more often IgE to Amb a 1, profilin, polcalcin and CCDs than subjects with a ratio >0.5. CONCLUSIONS: Mugwort-sensitized subjects have different IgE reactivity profiles to weed allergens, reflecting their exposure to various pollens. Subjects with a low ratio between the IgE levels to Art v 1 and mugwort have a diverse IgE reactivity profile, indicating a role for cross-reactive allergens in their mugwort sensitization.

Accuracy of specific IgE antibody assays for diagnosis of cow's milk allergy.

OBJECTIVE: The primary objective of this report was to discuss the accuracy of specific immunoglobulin (Ig)E antibody determinations in the diagnosis and prognosis of reactions to allergens, especially cow's milk, in the context of other relevant clinical information. DATA SOURCES: A review was undertaken of the relevant literature on IgE antibody assays in conjunction with some unpublished information from the authors' investigations. STUDY SELECTION: The pertinent data for this article were selected on the basis of the expert opinion of the authors. RESULTS: IgE antibody formation and allergy commence early in life, which can be reflected by specific IgE antibody determinations in serum samples with use of particular systems developed for commercial use. After the first such system was introduced in 1974, development of the technology has ensued. Some systems using excess of allergen extracts of good quality have proven to yield highly accurate results over time. Assays that detect all antibodies present in the serum sample and that demonstrate parallelism between dilutions of specific IgE antibodies and total IgE concentration also allow quantitative determinations of specific IgE antibodies. Such specific IgE antibody data can be used not only for a dichotomized evaluation of the presence or absence of sensitization in an individual patient, but also for an evaluation of the relative risk for a clinical reaction to an allergen such as cow's milk. Thus, the specific IgE antibody information can be used in the diagnosis, prediction of the course, and followup management of allergic disease, particularly when sensitization to multiple allergens is present. CONCLUSIONS: Specific IgE antibodies can be accurately determined with certain technologic systems. Such determinations provide information, not available by other means, for the diagnosis, prognosis, and followup of patients with allergy-like symptoms.