The immunology of extrinsic and intrinsic asthma.

It is now widely accepted that chronic mucosal inflammation plays an important role in the pathogenesis of asthma. This response involves the interaction of various cell types and is not the result of a single inflammatory cell acting in isolation. The present review describes the possible role of T lymphocytes in the inflammatory response of extrinsic (allergic) and intrinsic (nonallergic) asthma, focusing mainly on analysis of lymphocyte subpopulations, their activation state and cytokines produced in peripheral blood and bronchoalveolar lavages. Recent research suggests that there may be fundamental immunological differences between intrinsic and extrinsic asthma. In particular, intrinsic asthmatics have different patterns of T cell activation and cytokine production.