Mucosal regulatory T cells in airway hyperresponsiveness

Interest in regulatory T cells (Treg) and their role in immune regulation has grown almost exponentially over the last 10 years, though the notion of a suppressive population of T cells has been in existence since the early 1970s. Recent reports have highlighted the potential role of populations of Treg in control of T-cell-mediated inflammation in tissues, including the lung. In particular, there is now evidence to suggest that Treg form a fundamental part of the regulatory axis operating within the respiratory mucosa and that the number of Treg recruited to the airways may be crucial for the inhibition of airways hyperresponsiveness associated with exacerbations of asthma. A discussion of these concepts is the focus of this chapter.