Macrophage activity in asbestos related diseases

This paper indicates some immunological aspects of asbestos-related diseases and especially concerns the activity of macrophages--cells of immunological surveillance. Macrophages establish a very important population of cells which initiate or suppress specific immune response; they are responsible for effective T-cell activation, express antitumour activity. The process of lung fibrosis generated by the inhalation and deposition of asbestos fibres is also closely related to macrophage activity. An open question which is still to be resolved concerns asbestos-induced fibrosis; it may arise as a consequence of tissue injury and repair or change collagen synthesis. Another question is, to what extent macrophages may be protective cells and when they become undesirable? Since their overstimulation or damage in the case of chronic exposure to asbestos dust may be the reason of the increased release of inflammatory mediators, reactive oxygen intermediates which may in turn cause tissue injury, fibrosis or, in final effect, cancer. If so, we could then say that lung response (expressed by e.g. alveolar macrophage activity) to chemical insult may cause further damage to this tissue.