HDAC2 and chronic obstructive pulmonary disease: As already discussed, the cells of COPD patients, in response to oxidative stress, present reduced HDAC2 activity which has been linked to increased acetylation of the antioxidant transcription factor Nuclear respiratory factor 2 (Nrf 2), impairing Nrf 2 activity, and to the upregulation of antioxidant enzymes [91].