“The presence of nitrotyrosine in the airway epithelium (r= −0.841, P < 0.0001; r = −0.771, P = 0.0004) and inflammatory cells (r= −0.727, P = 0014; r= −0.681, P = 0.004) correlated inversely with methacholine PC20 and forced expiratory volume in 1 s, respectively.”