Humoral immunity alterations after environmental asbestos exposure.

The inhabitants of Metsovo in northwestern Greece have been environmentally exposed to asbestos from childhood because they had been using a tremolite-containing material for whitewash, without knowing its consistency. As a result, they have a very high incidence of calcified pleural plaques and malignant pleural mesothelioma but no pulmonary fibrosis. In the present study we examined certain aspects of the humoral immunity in the serum of 109 individuals: levels of immunoglobulins, C-reactive protein and complement components, as well as the presence of antinuclear antibodies, rheumatoid factor, antibodies to extractable nuclear antigens, to ds-DNA and to cardiolipin. Our results show that, compared to controls, those exposed to asbestos have increased IgG and C3 levels. Those with pleural plaques have, in addition, increased IgA levels and an increased incidence of antinuclear antibodies. The results of the study suggest that nonoccupational asbestos exposure affects humoral immunity. The presence of pleural plaques accentuates this effect.