CD8A and chronic obstructive pulmonary disease: Our initial observations revealed that COPD was accompanied with promoted cell migration and invasion, decreased E-cadherin expression, the ratio of CD3+, CD4+, CD8+ and CD4+/CD8+T lymphocytes, and levels of IgG, IgA, and IgM, and elevated N-cadherin expression and levels of IL-6 and TNF-α.