[On the association of tumor necrosis factor-alpha gene polymorphisms with the susceptibility to silicosis]

To find out whether -308 and -238 locus (G --> A) mutation within the tumor necrosis factor-alpha gene (TNF-alpha) promoter region are associated with susceptibility to silicosis in the Han population of southwest China.

Governed by the principles of voluntatiness and cooperation, 75 patients with silicosis and 137 control with silica-exposure but without silicosis were recruited, and additionally, 140 elderly patients with silicosis and 135 healthy elderly (retired) controls were recruited in this case-control study. 5 ml peripheral vein blood was drawn from each subject. By means of polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) and sequencing techniques, TNF-alpha gene polymorphisms of all subjects were analyzed.

The frequencies of TNF-alpha -308A and -238A in the 75 patients with silicosis were higher than those in the 137 controls (P < 0.01). After being adjusted for confounding factors, the -308A and the -238A were still associated with the presence of silicosis (P < 0.01). But the frequency of TNF-alpha -308A in the 140 elderly patients was significantly lower than that in the controls (P < 0.001).

TNF-alpha gene -308 and -238 locus (G --> A) mutation might be related to the occurrence of silicosis and the severity of pulmonary fibrosis in silicosis among the Han population of southwest China, and TNF2 (-308A) allele might increase the risk of the disease.