Correlation between level of autophagy and frequency of CD8(+) T cells in patients with chronic obstructive pulmonary disease

OBJECTIVE: The pathogenesis of chronic obstructive pulmonary disease (COPD) remains elusive. Here, we assessed the correlation between CD8(+) T cell frequencies and autophagy in COPD patients. METHODS: Subjects were divided into three groups (n = 30 patients/group): (1) COPD patients in the stable phase; (2) smokers with normal lung function; and (3) non-smokers with normal lung function. Flow cytometry was used to enumerate CD8+ T cell subsets (CD8(+), CD8(+) effector, and CD8(+) memory T cells) and quantitate T-cell apoptosis. RT-PCR and western blotting were used to measure levels of LC3 and p62. RESULTS: Frequencies of CD8(+) T cell subsets and expression of p62 and LC3 II/I were significantly higher in COPD patients compared with the other two groups, while the rate of apoptosis was lower. In COPD patients, LC3 II/I and p62 expression were positively correlated with CD8(+) T cell subset frequencies. Moreover, a significant correlation was observed between LC3 II/I and p62 expression and T cell subset frequencies. CONCLUSION: Autophagy level is positively correlated with the frequencies of CD8(+) T cells, suggesting that autophagy might be involved in COPD pathogenesis.