Abstract: To investigate the relations among the genetic polymorphism of human Heme Oxygenase1 promoter region, tumor necrosis factorα and susceptibility of chronic obstructive pulmonary disease(COPD). Method: The genetypes of 45 severe, earlyonset COPD patients, 60 common COPD patients and 60 control subjects were tested with PCRRFLP to analyse the GT repeat in HO1 promoter region and the polymorphism of TNFα308. Results: There were no difference between severe, earlyonset COPD patients and common COPD patients about cigarette smoking (OR 3.64 vs 4.75)， while both groups had a significant difference when comparing with control subjects separately. The L type allele frequencies in HO1 promoter region and the A type allele frequencies in TNFα308 of severe, earlyonset COPD patients and common COPD patients all showed a statistical significance compared with the control subjects; The A type allele frequencies in TNFα308 of severe, earlyonset COPD patients had a higher odds ratio（11.88 vs 3.30）. Both the HO1L type allele frequencies in promoter region and the A type allele frequencies in TNFα308 of the two groups played an interactive role with cigarette smoking. Conclusions: The L type allele of HO1 promoter region and the A type allele of TNFα308 are associated with earlyonset COPD and increase the risk of developing earlyonset

Key words: Lung diseases, obstructive, Severe, earlyonset, Heme oxygenase, Tumor necrosis factor, Geneticpredisposition to disease