[Host factors in asbestos-associated disease. A study in twins (author's transl)].

Observations in two pairs of identical twins illustrate the importance of genetic factors in determining the outcome of exposure to asbestos in relation to pleural plaques and bronchogenic carcinoma. The first pair of twins, laggers with french railroad (S.N.C.F.), were discovered fortuitously, after only several years exposure, to have bilateral pleural plaques and calcification at the same site on the axillary and diaphragmatic surfaces. The second set of twins developed epidermoïd bronchial carcinoma : one at the right hilum, the other postero-basally on the right in 1969 and 1977 respectively. Both were in ship-building and each had been exposed to asbestos in the same yard for 20 years between 1945 and 1965. Radiographs showed left sided pleural calcification and reticular shadowing at the bases in the two cases. These observations show the role of the host in the generation of asbestos disease. They are in keeping with studies on the presence of certain tissue types (HLA B27, and HLA B8) in those with asbestosis and of non-specific auto-antibodies (anti-nuclear factor, rheumatoid factor) in asbestosis, silicosis and the idiopathic pulmonary fibrosis. The relation between genetic factors and asbestos-induced cancer is suggested by the variable susceptibility of different kinds of animals to carcinogenesis in response to asbestos and by the increased inductibility of the enzyme system Aryl-hydrocarbon-hydroxylase in subjects exposed to this air-born contaminant who develop pleural tumours and/or bronchitis. There are only two other publications of bronchial carcinoma in twins in the literature.