Nineteen GSTM1 wild-type and eighteen GSTM1-null individuals with mild atopic asthma underwent methacholine and inhaled allergen challenges, and endobronchial allergen provocations through a bronchoscope.
We conclude that deletions of GSTM1 and GSTT1 could be risk factors for asthma and that the genes might have a protective role in the development of atopic asthma.