Sensitization to molecular dog allergens in an adult population: Results from the West Sweden Asthma Study

Abstract

Background: As the prevalence of dog allergy rises, component resolved diagnosis might improve the diagnosis, understanding of the clinical outcomes and the effectiveness of immunotherapy. Considering the paucity of data in adults, the current study characterized the patterns of sensitization to dog molecular allergens in an adult population.

Methods: Data were derived from the West Sweden Asthma Study, a population-based and representative sample of adults from western Sweden. Of the 2006 subjects clinically examined, 313 participants sensitized to whole dog allergen extract were measured for specific immunoglobulin E (sIgE) levels to Can f 1, Can f 2, Can f 3, Can f 4, Can f 5 and Can f 6 using ImmunoCAP™. Polysensitization was defined as sensitization to ≥3 components. Overlapping sensitization was defined as having concomitant sensitization to at least two dog molecular allergen families (lipocalin, albumin or prostatic kallikrein).

Results: Of 313, 218 (70%) subjects tested positive to at least one dog allergen component. Sensitization to Can f 1 (43%) was the most common, followed by Can f 5 (33%) among molecular allergens, while sensitization to lipocalins (56%) was the most common among component families. Polysensitization was found in 22% of all participants and was more common in participants with than in those without asthma. Subjects with asthma were less likely to be monosensitized to Can f 5 than those without asthma. Subjects with asthma had higher IgE levels of Can f 3, Can f 4 and Can f 6 than those without asthma. Overlapping sensitizations also differed between those with asthma and allergic rhinitis and those without.

Conclusion: Increased knowledge about the sensitization patterns of dog allergen components can aid in defining their role in asthma and rhinitis. In complex clinical cases of dog allergy, a detailed analysis of dog allergen components can provide additional information on the nature of sensitization.

Keywords: Can f 1; Can f 5; component resolved diagnostics; dog allergy; dog dander sensitization; dog molecular allergen components; furry animal allergy.

FIGURE 1

Venn diagram of the sIgE positivity for lipocalins (Can f 1, Can f 2, Can f 4 and Can f 6), albumin (Can f 3), and prostatic kallikrein (Can f 5) among those being found sensitized to at least one dog allergen component (A); among subjects with asthma (B); and without asthma (C). %, percentage of those sensitized to respective allergen components within each group; sIgE, specific immunoglobulin E. *Of note, one person can be sensitized to several dog allergen components and thus, the same person can be included in several of the groups.

FIGURE 2

Higher levels of sIgE to dog allergen components a seen more often in subjects with asthma than subjects without asthma. Venn diagram of the sIgE positivity to dog allergen components in subjects with asthma (A) and without asthma (B). Comparison of median sIgE levels to each dog allergen component by the presence of asthma vs non‐asthma (asthma n = 221, non‐asthma n = 92) in all study group (C). Comparison of median sIgE levels to each dog allergen component by the presence of asthma vs non‐asthma (asthma n = 160, non‐asthma n = 58) among subjects sensitized to at least one dog allergen component (D). e5, dog dander immunoglobulin E; sIgE, specific immunoglobulin E. In (C,D) data are presented as median, and whiskers indicate the minimum and maximum values. *Of note, one person can be sensitized to several dog allergen components and thus, the same person can be included in several of the groups. Whiskers indicate the minimum and maximum values.

FIGURE 3

Higher levels of Can f 5 are seen more often in subjects with allergic rhinitis than those without allergic rhinitis. Venn diagram of the sIgE positivity to lipocalin, albumin and prostatic kallikrein in subjects with allergic rhinitis (A), without allergic rhinitis (B). Comparison of median sIgE levels to each dog allergen component by the presence of allergic rhinitis (AR) vs without AR (AR n = 245, no AR n = 68) in all study group (C). Comparison of median sIgE levels to each dog allergen component by the presence of allergic rhinitis vs without AR (AR n = 174, no AR n = 44) among subjects sensitized to at least one dog allergen component (D). %, percentage of those sensitized to respective allergen components within each group; e5, dog dander immunoglobulin E; sIgE, specific immunoglobulin E. In (C,D) data are presented as median, and whiskers indicate the minimum and maximum values. *Of note, one person can be sensitized to several dog allergen components. and thus the same person can be included in several of the groups.

FIGURE 4

Current dog owners show increased levels of sIgE to Can f 3 and Can f 5. Venn diagram of the sIgE positivity for lipocalins, albumin and prostatic kallikrein among non‐current dog owners (A); among current dog owners (B). Comparison of median sIgE levels to each dog allergen component by current dog ownership (current dog owners n = 46, non‐current dog owners, n = 267) in all study group (C). Comparison of median sIgE levels to each dog allergen component by current dog ownership (current dog owners n = 35, non‐current dog owners, n = 183) among subjects sensitized to at least one dog allergen component (D). %, percentage of those sensitized to respective allergen components within each group. D, current dog ownership; e5, dog dander immunoglobulin E; sIgE, specific immunoglobulin E. In (C,D) data are presented as median, and whiskers indicate the minimum and maximum values. *Of note, one person can be sensitized to several dog allergen components and thus, the same person can be included in several of the groups.

FIGURE 5

Polysensitized subjects display increased levels of sIgE to each molecular allergen component compared to non‐polysensitized subjects. Comparison of median sIgE levels to dog allergen components by polysensitization (n = 68) vs no polysensitization (n = 245) in all study group (A). Comparison of median sIgE levels to dog allergen components by polysensitization (n = 68) vs no polysensitization (n = 150) among subjects sensitized to at least one dog allergen component (B). e5, dog dander immunoglobulin E; PS, polysensitization; sIgE, specific immunoglobulin E. Data are presented as median, and the minimum and maximum values.