γδ T Cells in Asthma

In this issue of Annals, Spinozzi and colleagues [1] report their observations on γδ T cells in the lungs of asthmatic patients. This is the first report of increased γδ T cells in the bronchoalveolar fluid from patients with asthma. Although they did not detect any γδ T cells in samples from the lungs of their controls or from patients with sarcoidosis, extrinsic allergic alveolitis, cystic fibrosis, or anatomic malformations of the airways, the finding of increased γδ T cells in the blood or in lung samples in patients with sarcoidosis and extrinsic allergic alveolitis has been previously reported [2-4]. Nevertheless, the finding of increased T cells in patients with asthma raises questions about the nature of these cells and their potential role in asthma.

T cells are a class of lymphocytes that undergo differentiation in the thymus and are the major regulatory cells of the immune system. They can secrete various cytokines that are important for both cellular and humoral responses. T cells can now be divided into two distinct populations on the basis of the T-cell antigen receptor (that is, α β or γδ) that they express. γδ T cells are a lineage of relatively recently discovered T cells that have many characteristics in common with the more prevalent α β T cells [5]. …