Abstract:
Chronic obstructive pulmonary disease (COPD) and silicosis are common disease
entities in Thailand. Environmental factors especially cigarette smoking and occupational
exposures are the greatest contributors to the disease development. Based on the evidence that
only a minority of cigarette smokers develops COPD and genetic background may contribute
to the disease pathogenesis. This is likely in silicosis that not all individuals develop severe
lung fibrosis despite having similar work histories. Although the major determinant of silicosis
is the level of exposure to silica containing dust, individual susceptibility to the disease may
also play an important role.
Tumor necrosis factor-alpha (TNF-), a potent proinflammatory cytokine, can damage
lung structure and/or sustaining neutrophilic inflammation. It also promotes bronchial smooth
muscle proliferation and alters smooth muscle function. The increment of sputum TNF-
levels and TNF- immunoreactivity in the airways of COPD patients were well recognized.
There is also evidence that TNF- plays an important role in the pathogenesis of silicosis and
the experimental inhibition of TNF receptors has been shown to protect mice from the
inflammatory and fibrotic effects of silica.
The promoter polymorphism of TNF- gene was associated with COPD and silicosis in
different study populations. The aim of the present study was to evaluate the frequency of
TNF- gene promotor polymorphisms in Thai patients with COPD and silicosis, and compare
them with the frequencies in appropriate control subjects; PCR-SSP was used to detect the
frequencies of TNF-. There were no significant differences in the distribution of TNF- gene
promoter among patient with COPD, smoker control subjects, and normal population control
subjects. But the distribution of TNF- -308 allele was significantly different between silicosis
patients and population control subjects (p<0.05).