Inhabitants of Metsovo, North-West Greece have been exposed to asbestos from use of a tremolite containing whitewash. As a result they have increased incidence of malignant pleural mesothelioma and pleural calcifications. However, those with calcifications have a much lower incidence of mesothelioma, than those without. Study of the two groups with bronchoalveolar lavage (BAL), revealed intense lymphocytic alveolitis, among those with calcifications. We suggested then, that this alveolitis may be somehow correlated with "protection" against neoplasia (S.H. Constantopoulos et al., Am Rev Respir Dis 1992). In the present report, we examine the liquid phase of BAL in the two groups. We evaluated 43 Metsovites with and 30 without pleural calcifications. The most obvious finding was the presence of two additional protein spots, corresponding to the electrophoretical site of immunoglobulin heavy chain and C4 component of complement. The two proteins were present in all Metsovites with pleural calcifications but in none without and also none of the control groups. Our study further separates two groups of Metsovites with different reaction to the asbestos fiber, possibly as a result of different activation of alveolar macrophages. This difference leads the first group to the formation of pleural calcifications, alveolitis and relatively low tendency to malignancy and the second group to no calcifications, no alveolitis, but also no "protection" against malignancy. Pneumon 2000, 13 (1): 14-22