GSTM1 and inflammatory response: Given the critical role airway epithelial cells play in the pathogenesis of airway inflammation, we manipulated GSTM1 levels in primary human bronchial epithelial cells (HBEC) from human volunteers with GSTM1 sufficient (GSTM1+) genotype using GSTM1 shRNA to determine whether GSTM1 deficiency could modulate DEP-induced pro-inflammatory response, herein, the over-expression of interleukin-8 (IL-8) and IL-1β proteins.