Background: Enzymes that contribute to the local detoxification in alveoli and bronchioles have an important role in the defence mechanism against tobacco smoke. It has been suggested that genetic susceptibility to smoking injury may confer a risk for the development of chronic obstructive pulmonary disease (COPD). The polymorphisms in glutathione S-transferase P1 (GSTP1), a xenobiotic metabolising enzyme, were investigated in patients with COPD.
Methods: Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were performed to genotype GSTP1 polymorphisms in exon 5 (Ile105Val) and exon 6 (Ala114Val). Blood samples were taken from 53 patients with COPD and 50 control subjects at the Tokyo University Hospital, the Juntendo University Hospital, and the Tokyo Kenbikyoin Clinic for use in the study.
Results: The proportion of GSTP1/Ile105 homozygotes was significantly higher in the patients with COPD than in the control subjects (79% vs 52%). The odds ratio for GSTP1/Ile105 homozygotes versus all other genotypes was 3.5 (95% CI 2.7 to 4.6) for COPD. Polymorphism at residue 114 of GSTP1 was not found in either group.
Conclusions: Genetic polymorphism of exon 5 of GSTP1 may be associated with COPD because the GSTP1/Ile105 genotype is predominantly found in COPD. It is suggested that the GSTP1/Ile105 genotype may be less protective against xenobiotics in tobacco smoke.