The level of HDAC2 protein in skeletal muscle of COPD patients (HDAC2/β-actin ratio: 0.59 ± 0.34) was significantly lower than that SM (1.9 ± 1.1, p = 0.0007) and NS (1.2 ± 0.7, p = 0.029; Fig. 1a). This evidence concerns the gene HDAC2 and chronic obstructive pulmonary disease.