IgE sensitization to house dust mite and cockroach allergens in asthmatic and allergic patients in the tropics.

Introduction: House dust mite (HDM) allergens are major triggers of IgE-mediated asthma in tropical regions, yet the role of cockroach allergens and their cross-reactivity with HDM remains unclear. Cross-reactivity among invertebrate allergens is a common challenge in daily practice, especially to define primary sensitizers and reactions of clinical relevance. Multiplexed arrays in molecular allergology constitute a useful tool for better detection and interpretation of cross-reactions. Methods: We assessed specific IgE levels and skin prick test reactivity to the American cockroach and HDM allergens in cohorts of allergic and asthmatic patients from Cartagena, Colombia, using ImmunoCAP™, skin testing, and multiplex molecular allergology (ALEX2). Results: Cockroach sensitization was present in 29%-40% of patients but elicited significantly lower IgE responses and smaller skin test wheals compared with HDM. Most cockroach-sensitized individuals were cosensitized to HDM, with limited recognition of cockroach molecular components. Mean specific IgE levels to cockroach were 2.1 kU/L ranging from 0.1 to 25.8 kU/L. The majority of patients had IgE levels in Class 1 (0.35-0.70 kU/L) or Class 2 (0.70-3.5 kU/L). In the ALEX2 array, most cockroach-sensitized patients (by skin tests) did not recognize the Discussion: HDM allergens induce stronger IgE responses than cockroach in this tropical population, indicating HDM as the primary sensitizer. Cockroach sensitization often reflects cross-reactivity and requires careful clinical evaluation to determine its relevance.