House dust mite allergen characterisation: implications for T-cell responses and immunotherapy.

T cells are central regulators and mediators of allergic sensitisation and disease. The house dust mite allergens are a biochemically diverse group of proteins which are present in extracts and the environment in a wide range of concentrations. Here the importance of ascertaining the contribution of the different allergens to Th2 lymphokine production and the development of allergy is discussed as well as the effect of allelic polymorphisms and inter-species sequence diversity on T-cell activation. The imbalances in allergen concentrations in commercial extracts, the sequence variations from allergens in the environment and the poor discrimination of allergy due to different mite species points to areas of improvement and the development of novel immunotherapeutic strategies and reagents.