Tumor Necrosis Factor- α Gene Polymorphism in Chronic Bronchitis

Abstract

Airway inflammation is an important pathologic feature in chronic bronchitis, and we hypothesized that individuals with greater inflammatory responses may be more likely to acquire the disease. A polymorphism at -308 position of the tumor necrosis factor-alpha (TNF-alpha) gene has been described, with the rarer allele, TNF2, demonstrated to have higher inducibility in vitro. We investigated the distribution of this polymorphism in a case-control study. The genotype was determined in 42 male patients with chronic bronchitis, 42 sex-, age-, and smoking index-matched control subjects, and 99 random-sampled schoolchildren. We report here that the TNF2 allele is overrepresented in the patient group. The allele frequency of TNF2 is 5.1% in the schoolchildren, 2.4% in the control group, and 19% in the bronchitis group (p < 0.01). Carriage of the TNF2 allele confers a higher risk to the development of chronic bronchitis (odds ratio = 11.1, 95% CI = 2.89-42.57). The results demonstrate the important pathologic role of TNF-alpha in chronic bronchitis and suggest that greater inflammatory response may predispose an individual to this disease.