In a previous study, gp91phox-/- mouse had a spontaneous pro-inflammatory phenotype and then a more exaggerated emphysematous phenotype in a cigarette-smoke induced mouse model, while a DKO mouse lacking in both gp91phox and MMP12 failed to develop emphysema even after chronic cigarette smoke exposure for over a month. The gene discussed is CYBB; the disease is pulmonary emphysema.