TGM2 and occupational asthma: Previous studies reported upregulation of TG2 in human asthmatic airways22, 23; in patients with exercise‐induced bronchoconstriction, TG2 expression was correlated with disease worsening.22, 23 Toluene diisocyanate, a well‐known inducer of occupational asthma, seems to activate TG2 in airway epithelial cells, resulting in airway inflammation.23