Frequent IgE recognition of Blomia tropicalis allergen molecules in asthmatic children and young adults in equatorial Africa

Abstract

BackgroundAsthma is not well investigated in equatorial Africa and little is known about the disease-associated allergen molecules recognized by IgE from patients in this area. The aim was to study the molecular IgE sensitization profile of asthmatic children and young adults in a semi-rural area (Lambaréné) of an equatorial African country (Gabon), to identify the most important allergen molecules associated with allergic asthma in equatorial Africa.MethodsFifty-nine asthmatic patients, mainly children and few young adults, were studied by skin prick testing to Dermatophagoides pteronyssinus (Der p), D. farinae (Der f), cat, dog, cockroach, grass, Alternaria and peanut. Sera were obtained from a subset of 35 patients, 32 with positive and 3 with negative skin reaction to Der p and tested for IgE reactivity to 176 allergen molecules from different allergen sources by ImmunoCAP ISAC microarray technology and to seven recombinant Blomia tropicalis (Blo t) allergens by IgE dot blot assay.ResultsThirty-three of the 59 patients (56%) were sensitized to Der p and 23 of them (39%) were also sensitized to other allergen sources, whereas 9 patients (15%) were only sensitized to allergen sources other than Der p. IgE serology analyses (n=35) showed high IgE-binding frequencies to the Blo t allergens Blo t 5 (43%), Blo t 21 (43%) and Blo t 2 (40%), whereas the Der p allergens rDer p 2, rDer p 21 and rDer p 5 (34%, 29% and 26%) were less frequently recognized. Only few patients showed IgE reactivity to allergens from other allergen sources, except to allergens containing carbohydrate determinants (CCDs) or to wasp venom allergens (i.e., antigen 5).ConclusionOur results thus demonstrate that IgE sensitization to mite allergens is very prevalent in asthmatics in Equatorial Africa with B. tropicalis allergen molecules representing the most important ones associated with allergic asthma.

Mite allergen sensitization patterns in Turkish children: Age‐related changes and molecular correlations

“…For example, DP is serodominant in sensitized allergic patients in the UK and New Zealand, while DF dominates in certain regions of the United States, and Blomia tropicalis is prevalent in South America and other tropical areas. 22,25,26 In our study, we found that DF was slightly more dominant compared with DP among sensitized individuals, with the leading allergen being Der f 2 and Der f 1, respectively.…”

Predicting Blomia tropicalis allergens using a multiomics approach

“…tropicalis allergens are considered major allergens, rBlo t 5 and rBlo t 21, which show IgE reactivity to 93% and 89% of sera from adult asthma patients, respectively 10 . A recent study showed high IgE‐binding frequencies for rBlo t 21 (43%) and rBlo t 2 (40%), whereas the other tested allergens were only recognized in the samples of a few patients (rBlo t 10, 6%; rBlo t 12, 3%) 11 . Overall, 27 antigen‐antibody precipitin complexes have been identified in B .…”

“… 10 A recent study showed high IgE‐binding frequencies for rBlo t 21 (43%) and rBlo t 2 (40%), whereas the other tested allergens were only recognized in the samples of a few patients (rBlo t 10, 6%; rBlo t 12, 3%). 11 Overall, 27 antigen‐antibody precipitin complexes have been identified in B . tropicalis by crossed radioimmunoelectrophoresis.…”