Mite component–specific IgE repertoire and phenotypes of allergic disease in childhood: The tropical perspective

Abstract

Sensitization to perennial aeroallergens correlates with the risk of persistent asthma (AS) in children. In tropical Singapore, multiple codominant species of mites abound in the indoor environment, and preferential species-specific sensitization has been associated with different phenotypes of allergic disease. We investigated the pattern of mite component-specific IgE (mcsIgE) in children with different phenotypes of clinical allergic disease in an environment with multiple mite species exposure. A prospective evaluation of newly diagnosed patients with clinical diagnosis of allergic rhinitis (AR), atopic dermatitis (AD), or AS and sensitization to one or more aeroallergens were performed. Sera were tested for specific IgE against an extensive panel of Dermatophagoides pteronyssinus and Blomia tropicalis allergens. A total of 253 children were included, mean age 7.3 yr, 79% fulfilled criteria for AR, 46% AS, 71% AD, and 31% for all three. Sensitization to one or both mites was observed in 91% of children, 89% were sensitized to D. pteronyssinus, and 70% to B. tropicalis. The most common mite allergens recognized by these atopic children were Der p 1 (64%), Der p 2 (71%), Blo t 5 (45%), Blo t 7 (44%), and Blo t 21 (56%). Specific IgE responses to an increased number of distinct mite allergens correlated with the complexity of the allergic phenotype. In multivariate analysis, an increased risk for the multi-systemic phenotype (AR + AS + AD) was associated with sensitization to an increased repertoire of mite components (three or more) (OR 4.3, 95% CI 2.1-8.8, p = 0.001) and a positive parental history of AS (OR 2.4, 95% CI 1.2-2.9, p = 0.013). A highly pleiomorphic IgE response to the prevalent indoor mites is associated with the presence of a multi-systemic allergic phenotype in childhood in a tropical environment.

NMR Structure and IgE Epitopes of Blo t 21, a Major Dust Mite Allergen from Blomia tropicalis

“…All of the patient sera were preadsorbed with 5 mg/ml of GST protein before use. The sera used in this study were prescreened for IgE responses to Blo t 21 in our previous study (7). Wild-type Blo t 21, GST, and mutant proteins were diluted in PBS to 20 g/ml.…”

“…Blo t 21 is able to elicit a positive allergic response in 57.9% (286 of 494) of atopic patients attending outpatient allergy clinics over 1.5 years (5). Following this, the patterns of mite component-specific IgE were investigated in a total of 253 atopic children (7). The results revealed that the most common mite allergens recognized were Der p 2 (71%), Der p 1 (64%), Blo t 21 (56%), Blo t 5 (45%), and Blo t 7 (44%) (7).…”

“…Following this, the patterns of mite component-specific IgE were investigated in a total of 253 atopic children (7). The results revealed that the most common mite allergens recognized were Der p 2 (71%), Der p 1 (64%), Blo t 21 (56%), Blo t 5 (45%), and Blo t 7 (44%) (7). Quantitatively, Blo t 21, Blo t 5, and Blo t 7 represented, on average, 36.2, 21.0, and 18.1% of the total specific IgE against B. tropicalis allergens, respectively (7).…”

“…The results revealed that the most common mite allergens recognized were Der p 2 (71%), Der p 1 (64%), Blo t 21 (56%), Blo t 5 (45%), and Blo t 7 (44%) (7). Quantitatively, Blo t 21, Blo t 5, and Blo t 7 represented, on average, 36.2, 21.0, and 18.1% of the total specific IgE against B. tropicalis allergens, respectively (7). These results suggest that Blo t 21 is a group of major allergens that is equally or even more important than Blo t 5 in B. tropicalis.…”

“…In contrast, Der p 1 and 2 represented ϳ46 and 29% of the total specific IgE against D. pteronyssinus allergens, respectively. IgE binding to mid-range allergens, such as Der p 21, Der p 7, and Der p 5, generally occurs only in individuals with high titer specific IgE to D. pteronyssinus (7).…”