[Immunology in medical practice. XXIX. Pathogenesis of allergic and immunologic pulmonary diseases]

Recently acquired insights into the complex functions of the immune system in the airways and lungs shed new light on the importance of local immunologic defence mechanisms in the maintenance of a normal lung function. Prolonged exposure to inhaled allergens or to aspecific injurious substances in the environment, in particular, may give rise to the onset of immunopathology that may manifest itself only years later. Clinically, the most common of such diseases is allergic asthma. This results from the interaction of an unknown number of genes with specific and aspecific environmental factors. In chronic obstructive pulmonary disease, exposure to such aspecific factors (cigarette smoking) is the most important aetiological factor. Immune-mediated diseases may also develop in the presence of congenital or acquired immunodeficiencies and in idiopathic diffuse pulmonary disorders. In addition, pulmonary disease is often a component of collagen diseases, occupational diseases and idiopathic pulmonary fibrosis. Recently developed investigational techniques such as bronchoalveolar lavage (BAL), cloning experiments on cells obtained by BAL, and ex vivo studies on cytokine production patterns are making an important contribution to the acquired understanding of the immunopathogenesis of pulmonary diseases.