T-cell co-stimulatory molecules: their role in allergic immune reactions.

The development of allergic diseases, such as allergic asthma, depends upon the initiation and maintenance of T-helper cell type-2-skewed allergen-specific immune reactions. Although it is clear that susceptibility to this process is under genetic and environmental control, the fine-tuning and regulation of the type-2 T-helper cell immune response is not yet fully understood. In this second article in the present series, current understanding regarding the involvement of T-cells and antigen-presenting cells is summarised, with emphasis on the interaction between these two types of immune regulatory cells by means of co-stimulatory molecules.