Time course of IL-13 and IL-31 in ipsilateral nasal secretions after unilateral nasal allergen challenge. The IL-13 (A, B) and IL-31 (C, D) concentrations (A, C) and contents (B, D) in ipsilateral nasal secretions are shown. Nasal secretions were collected before and at all time-points following allergen challenge. The dashed line represents values obtained after control challenge on a separate day using the same protocol. Values presented are means ± SEM (n = 7; *p < 0.05).