ATG4D and chronic obstructive pulmonary disease: Similar statistically significant values were encountered in the immunoexpression of ATG4A (p = 0.0036, Figure 2A), ATG4B (p = 0.0054, Figure 2B), ATG4C (p = 0.0064, Figure 2C), ATG4D (p = 0.0084, Figure 2D), ATG5 (p = 0.0088, Figure 2E), and ATG7 (p = 0.018, Figure 2F) in alveolar lining of stable COPD compared to CS and CNS patients.