Objective: Fas/APO-1 (CD95) and Fas Ligand (FasL) is a major mediator system that activates programmed cell death (apoptosis) and is most important for pulmonary cellular homeostasis. Another form of Fas, circulating soluble Fas (sCD95), produced by alternative mRNA splicing antagonizes the cell-surface Fas function. It was the aim of the study to test the hypothesis that the Fas/FasL system is implicated in the development of silica-induced pulmonary nodular lesions.
Material and methods: We investigated the serum levels of sCD95 in 55 former hard coal miners. Coal workers' pneumoconiosis (CWP) was assumed when the profusion of small round opacities according to the ILO 2000 classification system was 1/1 or greater. Analyses of sCD95 were performed by a sandwich ELISA.
Results: Radiologic CWP was found in 34 of the 55 individuals. The age of subjects with and without CWP was similar (73.5 (SD 7.2) years vs. 73.5 (7.1) years; P = 0.924). sCD95 could be quantified in all samples; significantly higher levels were observed in subjects with radiologic signs of CWP (914 (752-1251) pg/ml vs. 632 (509-804) pg/ml, P < 0.001). However, there was no relationship between sCD95 serum concentrations and the quantity of profusion according to ILO.
Conclusions: The hypothesis of elevated sCD95 concentrations in CWP was corroborated. The usefulness of sCD95 for prevention and diagnosis of CWP and other forms of silica-induced fibrosis needs to be established by epidemiological studies.