HDAC2 and chronic obstructive pulmonary disease: Macrolide antibiotics have been proven effective in treating CRS patients with GCR.[190,191] The study has demonstrated that theophylline can effectively restore HDAC2 activity in macrophages of patients with COPD to normal levels, thus reversing GCR.[192] After being exposed to cigarette smoke, mice exhibiting GC-resistant inflammatory reactions have shown a reversal of their symptoms upon administration of theophylline.