CD8+ T lymphocytes and leukotriene B4:: Novel interactions in the persistence and progression of asthma

The contribution of CD8(+) T cells to the development of airway hyperresponsiveness and airway inflammation has received increased attention recently. CD8(+) T cells, which are capable of secreting T(H)2 cytokines, including IL-4, IL-5, and IL-13, have been described in asthmatic subjects and in animals sensitized and challenged with allergen. A subset of these IL-13-producing CD8(+) T cells, effector memory CD8(+) T cells in the mouse, express a high-affinity receptor for leukotriene B-4 (BLT1), and expression of this receptor is essential for their accumulation in the lung and development of airway hyperresponsiveness and airway inflammation. A similar subset of CD8(+)/BLT1(+)/IL-13(+) T cells has also been identified in the bronchoalveolar lavage fluid of asthmatic subjects, suggesting a pathogenic role for this unique subset of CD8(+) T cells in asthma.