OBJECTIVETo investigate the changes of levels and clinic significance of serum soluble Fas (sFas) and soluble FasL (sFasL) in coal workers' pneumonoconiosis.

METHODSSerum levels of sFas and sFasL were determined in 52 patients with silicosis, 57 coal workers' pneumonoconiosis, 46 healthy underground coal workers' (the underground control group) and 40 healthy volunteers working on the ground (the ground control group) with a sandwich ELISA.

RESULTSCompared to the underground control and the ground control group, the serum levels of sFas and sFasL in the patients with silicosis and the coal workers' pneumonoconiosis were significantly higher (P < 0.01). Serum levels of sFas and sFasL in the underground control group were significantly higher than those in the ground control group (P < 0.01); Serum sFas levels in coal workers' pneumonoconiosis was significantly higher than those in the patients with silicosis (P < 0.01). Although the serum sFasL levels was also increased, there was no significant difference (P > 0.05). In the patients with silicosis and the coal workers' pneumonoconiosis patients, the serum sFas levels in Phase I patients combined with emphysema and simple Phase II + III patients were significantly higher than those in simple Phase I patients (P < 0.01). There was no significant difference in the serum sFasL levels among various groups with different parameters of pneumonoconiosis. In the patients with silicosis and the coal workers' pneumonoconiosis, serum levels of sFas and sFasL were not significantly altered among different duration of exposure to dusts. There was no correlation between serum levels of sFas and sFasL in the patients with silicosis while there was a slightly positive correlation between sFas and sFasL levels in the coal workers' pneumonoconiosis (r = 0.479, P < 0.05).

CONCLUSIONIn the patients with silicosis and the coal workers' pneumonoconiosis, the serum levels of sFas and sFasL are abnormal and associated with the development of the pneumonoconiosis. The changes of serum sFas levels may indicate the development and progression of the pneumonoconiosis. The detection of the serum sFas level may be used in the differential diagnosis for the silicosis and the coal worker's pneumonoconiosis.