Differentially methylated regions were detected in parenchymal fibroblasts in COPD, located in genes such as TMEM44 (Transmembrane protein 44), RPH3AL (Rabphilin 3 A like), WNT3A (Wnt family member 3 A), HLA-DP1 (Major histocompatibility complex, class II, DP beta 1), and HLA-DRB5 (Major histocompatibility complex, class II, DR beta 5) [47]. Here, HLA-DRB5 is linked to chronic obstructive pulmonary disease.