RESUMEN
Chronic tobacco smoking is a major risk factor in the development of COPD. However, it is estimated that only 10-20% of chronic heavy smokers will develop symptomatic COPD. This indicates the possible contribution of environmental or genetic cofactors to the development of COPD in smokers. The present work aimed to study the relationship between GST polymorphism and susceptibility to and severity of COPD in smokers. A case control study was done on 140 patients with COPD and 140 matched controls. All subjects were smokers or exsmokers. The GSTM1 and GSTT1 genotypes were identified by polymerase chain reaction in peripheral blood DNA samples. Analysis of data was done by IBM computer using SPSS program. Results shown that the proportion of GSTMl-null genotypes was significantly higher in patients with COPD than in control subjects [62.2% versus 32.2%]. The odds ratio was 3.5 [95% confidence interval [CI] = 2.1-5.7]. Moreover the patients with GSTM1 null genotype were at high risk of developing the severe type of COPD. The odds ratio was 3.2 and [95% CI = 1.5-6.7]. However the genotype frequencies of GSTTl-null genotype did not show significant difference between groups. Our data provide evidence that smokers with null genotype of GSTM1 were more susceptible to develop the severe type of COPD