Study of lung antibodies in patients with silicosis.

The presence of lung antibodies was determined in a group of 68 patients with silicosis in various stages of evolution and in a control group of 35 healthy subjects, by the standard indirect immunofluorescent technique with fluorescent conjugate anti human gammaglobulin and monospecific fluorescent conjugates anti human IgG, IgA and IgM. In the group of patients investigated, lung antibodies were detected by means of fluorescent conjugate anti human gammaglobulin, in 47 cases of the 68 examined. As regards the investigations using monospecific fluorescent conjugates it was observed that all the 47 patients presented lung antibodies of the IgG class, 32 presented lung antibodies of the IgA class and 15 presented lung antibodies of the IgM class. The presence of lung antibodies in silicotic patients suggests the participation of acquired humoral immunity in the pathogeny of disease without, however, being directly responsible for the evolution of disease. The association of silicosis with various other autoimmune diseases pleads for the existence of an immune component in the evolution of this pneumoconiosis.