CD8A and chronic obstructive pulmonary disease: CS has been shown to reduce the levels of IL‐8, TNF‐α, TGF‐β1, MDA, Th17/Treg, Th17, and CD8 + ; increase CD3 + , CD4 + , CD4 + /CD8 + , and SOD levels; and regulate the PI3K/Akt and CAMP signalling pathways to alleviate symptoms of COPD [31].