IL-5 T-cell responses to house dust mite are associated with the development of allergen-specific IgE responses and asthma in the first 5 years of life

Background: Allergen-specific T(H)2-like cytokine responses are considered to be important in sensitization and allergic diseases. Objective: To examine the profile of house dust mite (HDM) stimulated T-cell cytokines and their relationship to allergic disease in children over the period of the first 5 years of life. Methods: Subjects with a family history of asthma who were enrolled antenatally in the Childhood Asthma Prevention Study and had skin prick tests, clinical evaluation for asthma and eczema, and in vitro assessment of lymphocyte cytokine responses to HDM extract performed at ages 18 months (n = 281), 3 years (n = 349), and 5 years (n = 370). IL-13 at 3 and 5 years and IL-5, IL-10, and IFN-gamma at 18 months, 3 years, and 5 years were measured by ELISA. Results: House dust mite-specific cytokine responses increased with age for all cytokines except IFN-gamma. HDM-specific IL-5 responses at 3 years and 5 years were significantly positively related to skin prick test positivity at 5 years. IL-5 responses at 5 years were also significantly related to asthma at 5 years. Other HDM-specific cytokine responses were not related to asthma or eczema at 5 years. Responses were not altered by a HDM avoidance intervention. Conclusion: IL-5 responses to HDM, the dominant local inhalant allergen, are related to the expression of clinical illness at age 5 years. Clinical implications: The T-cell response to HDM, as reflected in IL-5 production, is acquired over the first years of life and may play a role in the expression of allergic airways disease.