Lymphocytic alveolitis and pleural calcifications in nonoccupational asbestos exposure. Protection against neoplasia?

Inhabitants of the Metsovo area in Northwest Greece (population, 4,000) have been exposed to asbestos through the use of whitewash containing tremolite. This has resulted in endemic pleural calcifications (PCs) and increased incidence of malignant pleural mesothelioma (MPM). In order to evaluate the lung response to the fiber, bronchoalveolar lavage (BAL) was performed in 25 Metsovites; 14 with PCs, three with PCs and neoplasia, five without PCs, and three without PCs but with established neoplasia. There were no differences between the four groups with regard to age or exposure. Twelve Metsovites had lymphocytic alveolitis (BAL lymphocytes > 15%). Eleven belonged to the group with PCs and one belonged to the group without PCs. None of those with neoplasia had alveolitis. The lymphocytes were mainly helper T-cells, and activation markers were more frequent among those with PCs. We have previously reported on the relative absence of PCs in Metsovites with malignant pleural mesothelioma. This observation and the results of the present study suggest that lymphocytic alveolitis correlates with pleural calcifications, whereas both are rarely present in patients with neoplasia.