[Pathogenesis of interstitial pulmonary changes with collagen diseases--therapeutic implications]

Autoantibodies, immune complexes and autoreactive lymphocytes represent the initial steps in the pathogenic events leading to interstitial pulmonary manifestations of collagen vascular diseases. Vascular damage caused by deposition of immune complexes in the vascular wall and chemotactic factors result in an influx of neutrophils and mononuclear cells leading to inflammatory phenomena like vasculitis and alveolitis. Finally, persistent activation of lung fibroblasts may result in interstitial pulmonary fibrosis characterized by nearly identical histopathological findings independent of the underlying disease. Several inflammatory mediators, e.g. cytokines, are markedly involved in the regulation of different pathogenic mechanisms. Furthermore, different pathogenic mechanisms exert variable roles depending on the specificity of the underlying disease. Therefore, disease-specific effective pharmacotherapy, which in most cases will be a combination therapy, has to take into consideration not only the predominant pathogenic mechanisms but also drug-specific efficacy.