Background: Sensitization to Blomia tropicalis is associated with asthma in various tropical and subtropical countries; however, information about the specific molecular components associated with this disease is scarce.
Objective: Using molecular diagnosis, we sought to identify B tropicalis allergens associated with asthma in Colombia.
Methods: Specific IgE (sIgE) to 8 B tropicalis recombinant allergens (Blo t 2, 5, 7, 8, 10, 12, 13, and 21) was determined using an in-house ELISA system in asthma patients (n=272) and controls (n=298) recruited in a national prevalence study performed in several Colombian cities (Barranquilla, Bogotá, Medellín, Cali, and San Andrés). The study sample included children and adults (mean [SD] age, 28 [17] years). Cross-reactivity between Blo t 5 and Blo t 21 was evaluated using ELISA-inhibition.
Results: Sensitization to Blo t 21 (aOR, 1.9; 95%CI, 1.2-2.9) and Blo t 5 (aOR, 1.6; 95%CI, 1.1-2.5), but not Blo t 2, was associated with asthma. sIgE levels to Blo t 21 and to Blo t 5 were significantly higher in the disease group. Cross-reactivity between Blo t 21 and Blo t 5 is on average moderate in frequency; however, analysis of individual cases indicates that it may be very frequent (>50%) in some cases.
Conclusions: Although Blo t 5 and Blo t 21 are considered common sensitizers, this is the first report of their association with asthma. Both components should be included in molecular panels for diagnosis of allergy in the tropics.

Key words: Asthma, Molecular diagnosis, Component-resolved diagnostics, Allergy, Blomia tropicalis, IgE, Recombinant allergens, Multiplex platform, House dust mites, Case-control study, Precision medicine