Correlates of cockroach nasal challenge responsiveness among sensitized urban children with asthma.

Background: The nasal allergen challenge (NAC) is a tool for evaluating upper airway allergic responses. In the CRITICAL study, NAC with cockroach allergen was used to confirm clinical reactivity in sensitized individuals from urban environments before enrollment onto a subcutaneous immunotherapy trial. Objective: Immunologic and transcriptomic predictors of NAC responsiveness were identified. Methods: NAC was performed in 103 participants. Clinical responses were assessed by the Total Nasal Symptom Score (TNSS) and sneeze score (TSNEEZ), which scale positively with symptom severity. Baseline immunologic markers-including skin prick test wheal size, cockroach-specific IgE, IgG, and IgG Results: Larger skin prick test wheal sizes were significantly associated with positive NAC outcomes (2.2 mm larger than negative NAC) and lower reactive doses (hazard ratio = 1.10). Cockroach (i6 extract)-specific IgE levels were inversely correlated with TNSS, while levels of IgE, IgG, and IgG Conclusion: NAC responsiveness to cockroach extract is influenced by skin test reactivity, T- and B-cell regulation, and nasal gene expression. These findings highlight the role of both adaptive and innate immunity in allergic airway responses and suggest potential biomarkers for clinical reactivity.