TLR4 Asp299Gly and Thr399Ile polymorphisms are very rare in the Chinese population

Endotoxin is an important component of bio-aerosols that contribute to airway inflammation and airflow obstruction. Toll-like receptor 4 (TLR4) mediates the host response to bacterial lipopolysaccharide (LPS), and the Asp299Gly and Thr399Ile polymorphisms have been associated with the development of respiratory diseases. We hypothesized that TLR4 polymorphisms may be associated with a decline of lung function in cotton workers who were exposed continuously to endotoxin. We investigated these two polymorphisms in our 20-year longitudinal cohort of Han Chinese cotton and silk textile workers. The two polymorphisms were genotyped using TaqMan and PCR-restriction fragment length polymorphism methods. No homozygous or heterozygous variant genotypes of the Asp299Gly and Thr339Ile polymorphisms were detected in 491 samples of this population. Our results suggest that the TLR4 Asp299Gly and Thr339Ile polymorphisms are very rare in the Chinese population.