ELEVATED INTERLEUKIN-8 IN THE ALVEOLITIS OF INDIVIDUALS WITH ASBESTOSEXPOSURE

Asbestosis is a fibrotic and inflammatory interstitial lung disease oc curring after chronic occupational exposure to asbestos. An alveolitis has been described with activated alveolar macrophages and increased neutrophils as sampled by bronchoalveolar lavage (BAL). Animal models and in vitro studies demonstrate that asbestos can stimulate alveolar macrophages to release neutrophil chemotactic factor. We performed BAL on 18 nonsmoking individuals with asbestos exposure and observed a tw ofold increase in percent neutrophils recovered. Alveolar macrophages cultured in vitro from the asbestos-exposed individuals spontaneously released significant amounts of the neutrophil chemotaxin, interleukin -8 (IL-8). In addition, the alveolar macrophages expressed a 2.7-fold increase in steady state mRNA levels compared to unexposed normal cont rols utilizing the reverse transcriptase/polymerase chain reaction. In vitro experiments confirmed that crocidolite or chrysotile asbestos c ould stimulate the release of IL-8 from mononuclear phagocytes in a do se-dependent fashion. We conclude that asbestos exposure causes a mild neutrophilic alveolitis, and that IL-8 is one potential mediator capa ble of contributing to this inflammation in the lower respiratory trac t.