OBJECTIVETo explore changes of Clara cell protein (CC16) and surfactant protein-D (SP-D) in the serum of patients with silicosis.

METHODThe concentrations of CC16 and SP-D were measured in the serum by sandwich enzyme-linked immunosorbent assays. The subjects consisted of 30 healthy volunteers and 90 silica-exposed workers including silica-exposed group, the silicosis of suspects group (0(+)) and the silicosis phase I group, 30 subjects each groups.

RESULTSThe concentrations of CC16 in the serum was significantly decreased in silica-exposed workers compared to controls (P < 0.01); The concentrations of CC16 in the serum were higher in lifelong nonsmokers than the current smokers in control subjects (P < 0.05), but they were no differences between lifelong nonsmokers and current smokers of 90 silica-exposed workers. Compared with control subjects, the levels of SP-D in the serum of silicosis suspects (0(+)) and silicosis phase I groups were significantly elevated (P < 0.01, respectively), which were also higher than silica-exposed group (P < 0.05 and P < 0.01, respectively), Discriminant equations set by CC16 and SP-D were used in diagnosis of silicosis, and the rate of accuracy in healthy volunteers, the silica-exposed group and the silicosis phase I group were 86.7%, 86.7% and 76.7%, respectively, The total rate of correct classification hit 84.2%.

CONCLUSIONThe serum CC16 of long-term silica-exposed workers is decreased, and SP-D is increased gradually.