GSTM1, GSTT1, and GSTP1 gene polymorphisms modify the effect of smoking on serum immunoglobulin E level

Abstract

Immunoglobulin E (IgE) plays an important role in the development of allergic disorders including asthma. Cigarette smoking was reported to elevate serum IgE level and air pollutants such as NO2 have been reported to modulate the immune system including inflammation. Moreover, genetic polymorphisms of glutathione S-transferases (GSTs) were reported to affect inflammatory diseases including asthma. Therefore, in the present study we tried to investigate whether tobacco smoke or NO2 exposure increases the level of IgE and the GST gene polymorphisms are associated with change of IgE level due to tobacco smoke or NO2 exposure. We measured urinary cotinine, personal NO2 exposure, and serum IgE levels in 300 healthy university students without allergic disorders. Allelic loss of the GSTM1 and GSTT1 and the GSTP1 (Ile105Val) polymorphism were determined by PCR and RFLP. Total serum IgE levels were significantly different according to urinary cotinine levels (P=0.046), while NO2 passive dosimeter level and genetic polymorphisms of three GSTs were not associated with total IgE level. Moreover, subjects with cotinine 500 mu g/g creatinine or more showed the highest level of total IgE when they had null type of GSTM1, null type of GSTT1, or variant type. of GSTP1 (P<0.05). When we considered IgE level according to urinary cotinine levels in strata with the combinations of GSTM1, GSTT1, and GSTP1 genetic polymorphisms, the subjects with GSTM1 null, GSTT1 null, and GSTP1 variant types showed the largest difference between IgE levels of subpopulations according to cotinine levels (P=0.030). However, there was no significant difference between IgE levels of subpopulations according to NO2 passive dosimeter levels in any group with combinations of GSTM1, GSTT1, and GSTP1 polymorphisms. This result suggests that smoking increases allergic response measured as IgE level and combinations of the GSTM1, GSTT1, and GSTP1 polymorphisms modify the effect of smoking on serum IgE level.