SOD1 and chronic obstructive pulmonary disease: Despite no difference in Nrf2 / Keap-1 protein or gene expression in alveolar macrophages, we showed an increase in the expression of classic Nrf2 target proteins NQO1 and HMOX1 and other anti-oxidants SOD1 and TXNRD1 in alveolar macrophages from COPD patients.